From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001
From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Date: Fri, 4 Sep 2026 10:43:19 +0200
Subject: selftests/bpf: Reject graph kptr use after RCU unlock

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 drivers/video/fbdev/cirrusfb.c | 2954 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 2954 insertions(+)
 create mode 100644 drivers/video/fbdev/cirrusfb.c

(limited to 'drivers/video/fbdev/cirrusfb.c')

diff --git a/drivers/video/fbdev/cirrusfb.c b/drivers/video/fbdev/cirrusfb.c
new file mode 100644
index 000000000..2693b5cc0
--- /dev/null
+++ b/drivers/video/fbdev/cirrusfb.c
@@ -0,0 +1,2954 @@
+/*
+ * drivers/video/cirrusfb.c - driver for Cirrus Logic chipsets
+ *
+ * Copyright 1999-2001 Jeff Garzik <jgarzik@pobox.com>
+ *
+ * Contributors (thanks, all!)
+ *
+ *	David Eger:
+ *	Overhaul for Linux 2.6
+ *
+ *      Jeff Rugen:
+ *      Major contributions;  Motorola PowerStack (PPC and PCI) support,
+ *      GD54xx, 1280x1024 mode support, change MCLK based on VCLK.
+ *
+ *	Geert Uytterhoeven:
+ *	Excellent code review.
+ *
+ *	Lars Hecking:
+ *	Amiga updates and testing.
+ *
+ * Original cirrusfb author:  Frank Neumann
+ *
+ * Based on retz3fb.c and cirrusfb.c:
+ *      Copyright (C) 1997 Jes Sorensen
+ *      Copyright (C) 1996 Frank Neumann
+ *
+ ***************************************************************
+ *
+ * Format this code with GNU indent '-kr -i8 -pcs' options.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ *
+ */
+
+#include <linux/aperture.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/delay.h>
+#include <linux/fb.h>
+#include <linux/init.h>
+
+#ifdef CONFIG_ZORRO
+#include <linux/zorro.h>
+#endif
+#ifdef CONFIG_PCI
+#include <linux/pci.h>
+#endif
+#ifdef CONFIG_AMIGA
+#include <asm/amigahw.h>
+#endif
+
+#include <video/vga.h>
+#include <video/cirrus.h>
+
+/*****************************************************************
+ *
+ * debugging and utility macros
+ *
+ */
+
+/* disable runtime assertions? */
+/* #define CIRRUSFB_NDEBUG */
+
+/* debugging assertions */
+#ifndef CIRRUSFB_NDEBUG
+#define assert(expr) \
+	if (!(expr)) { \
+		printk("Assertion failed! %s,%s,%s,line=%d\n", \
+		#expr, __FILE__, __func__, __LINE__); \
+	}
+#else
+#define assert(expr)
+#endif
+
+#define MB_ (1024 * 1024)
+
+/*****************************************************************
+ *
+ * chipset information
+ *
+ */
+
+/* board types */
+enum cirrus_board {
+	BT_NONE = 0,
+	BT_SD64,	/* GD5434 */
+	BT_PICCOLO,	/* GD5426 */
+	BT_PICASSO,	/* GD5426 or GD5428 */
+	BT_SPECTRUM,	/* GD5426 or GD5428 */
+	BT_PICASSO4,	/* GD5446 */
+	BT_ALPINE,	/* GD543x/4x */
+	BT_GD5480,
+	BT_LAGUNA,	/* GD5462/64 */
+	BT_LAGUNAB,	/* GD5465 */
+};
+
+/*
+ * per-board-type information, used for enumerating and abstracting
+ * chip-specific information
+ * NOTE: MUST be in the same order as enum cirrus_board in order to
+ * use direct indexing on this array
+ * NOTE: '__initdata' cannot be used as some of this info
+ * is required at runtime.  Maybe separate into an init-only and
+ * a run-time table?
+ */
+static const struct cirrusfb_board_info_rec {
+	char *name;		/* ASCII name of chipset */
+	long maxclock[5];		/* maximum video clock */
+	/* for  1/4bpp, 8bpp 15/16bpp, 24bpp, 32bpp - numbers from xorg code */
+	bool init_sr07 : 1; /* init SR07 during init_vgachip() */
+	bool init_sr1f : 1; /* write SR1F during init_vgachip() */
+	/* construct bit 19 of screen start address */
+	bool scrn_start_bit19 : 1;
+
+	/* initial SR07 value, then for each mode */
+	unsigned char sr07;
+	unsigned char sr07_1bpp;
+	unsigned char sr07_1bpp_mux;
+	unsigned char sr07_8bpp;
+	unsigned char sr07_8bpp_mux;
+
+	unsigned char sr1f;	/* SR1F VGA initial register value */
+} cirrusfb_board_info[] = {
+	[BT_SD64] = {
+		.name			= "CL SD64",
+		.maxclock		= {
+			/* guess */
+			/* the SD64/P4 have a higher max. videoclock */
+			135100, 135100, 85500, 85500, 0
+		},
+		.init_sr07		= true,
+		.init_sr1f		= true,
+		.scrn_start_bit19	= true,
+		.sr07			= 0xF0,
+		.sr07_1bpp		= 0xF0,
+		.sr07_1bpp_mux		= 0xF6,
+		.sr07_8bpp		= 0xF1,
+		.sr07_8bpp_mux		= 0xF7,
+		.sr1f			= 0x1E
+	},
+	[BT_PICCOLO] = {
+		.name			= "CL Piccolo",
+		.maxclock		= {
+			/* guess */
+			90000, 90000, 90000, 90000, 90000
+		},
+		.init_sr07		= true,
+		.init_sr1f		= true,
+		.scrn_start_bit19	= false,
+		.sr07			= 0x80,
+		.sr07_1bpp		= 0x80,
+		.sr07_8bpp		= 0x81,
+		.sr1f			= 0x22
+	},
+	[BT_PICASSO] = {
+		.name			= "CL Picasso",
+		.maxclock		= {
+			/* guess */
+			90000, 90000, 90000, 90000, 90000
+		},
+		.init_sr07		= true,
+		.init_sr1f		= true,
+		.scrn_start_bit19	= false,
+		.sr07			= 0x20,
+		.sr07_1bpp		= 0x20,
+		.sr07_8bpp		= 0x21,
+		.sr1f			= 0x22
+	},
+	[BT_SPECTRUM] = {
+		.name			= "CL Spectrum",
+		.maxclock		= {
+			/* guess */
+			90000, 90000, 90000, 90000, 90000
+		},
+		.init_sr07		= true,
+		.init_sr1f		= true,
+		.scrn_start_bit19	= false,
+		.sr07			= 0x80,
+		.sr07_1bpp		= 0x80,
+		.sr07_8bpp		= 0x81,
+		.sr1f			= 0x22
+	},
+	[BT_PICASSO4] = {
+		.name			= "CL Picasso4",
+		.maxclock		= {
+			135100, 135100, 85500, 85500, 0
+		},
+		.init_sr07		= true,
+		.init_sr1f		= false,
+		.scrn_start_bit19	= true,
+		.sr07			= 0xA0,
+		.sr07_1bpp		= 0xA0,
+		.sr07_1bpp_mux		= 0xA6,
+		.sr07_8bpp		= 0xA1,
+		.sr07_8bpp_mux		= 0xA7,
+		.sr1f			= 0
+	},
+	[BT_ALPINE] = {
+		.name			= "CL Alpine",
+		.maxclock		= {
+			/* for the GD5430.  GD5446 can do more... */
+			85500, 85500, 50000, 28500, 0
+		},
+		.init_sr07		= true,
+		.init_sr1f		= true,
+		.scrn_start_bit19	= true,
+		.sr07			= 0xA0,
+		.sr07_1bpp		= 0xA0,
+		.sr07_1bpp_mux		= 0xA6,
+		.sr07_8bpp		= 0xA1,
+		.sr07_8bpp_mux		= 0xA7,
+		.sr1f			= 0x1C
+	},
+	[BT_GD5480] = {
+		.name			= "CL GD5480",
+		.maxclock		= {
+			135100, 200000, 200000, 135100, 135100
+		},
+		.init_sr07		= true,
+		.init_sr1f		= true,
+		.scrn_start_bit19	= true,
+		.sr07			= 0x10,
+		.sr07_1bpp		= 0x11,
+		.sr07_8bpp		= 0x11,
+		.sr1f			= 0x1C
+	},
+	[BT_LAGUNA] = {
+		.name			= "CL Laguna",
+		.maxclock		= {
+			/* taken from X11 code */
+			170000, 170000, 170000, 170000, 135100,
+		},
+		.init_sr07		= false,
+		.init_sr1f		= false,
+		.scrn_start_bit19	= true,
+	},
+	[BT_LAGUNAB] = {
+		.name			= "CL Laguna AGP",
+		.maxclock		= {
+			/* taken from X11 code */
+			170000, 250000, 170000, 170000, 135100,
+		},
+		.init_sr07		= false,
+		.init_sr1f		= false,
+		.scrn_start_bit19	= true,
+	}
+};
+
+#ifdef CONFIG_PCI
+#define CHIP(id, btype) \
+	{ PCI_VDEVICE(CIRRUS, id), .driver_data = (btype) }
+
+static struct pci_device_id cirrusfb_pci_table[] = {
+	CHIP(PCI_DEVICE_ID_CIRRUS_5436, BT_ALPINE),
+	CHIP(PCI_DEVICE_ID_CIRRUS_5434_8, BT_SD64),
+	CHIP(PCI_DEVICE_ID_CIRRUS_5434_4, BT_SD64),
+	CHIP(PCI_DEVICE_ID_CIRRUS_5430, BT_ALPINE), /* GD-5440 is same id */
+	CHIP(PCI_DEVICE_ID_CIRRUS_7543, BT_ALPINE),
+	CHIP(PCI_DEVICE_ID_CIRRUS_7548, BT_ALPINE),
+	CHIP(PCI_DEVICE_ID_CIRRUS_5480, BT_GD5480), /* MacPicasso likely */
+	CHIP(PCI_DEVICE_ID_CIRRUS_5446, BT_PICASSO4), /* Picasso 4 is 5446 */
+	CHIP(PCI_DEVICE_ID_CIRRUS_5462, BT_LAGUNA), /* CL Laguna */
+	CHIP(PCI_DEVICE_ID_CIRRUS_5464, BT_LAGUNA), /* CL Laguna 3D */
+	CHIP(PCI_DEVICE_ID_CIRRUS_5465, BT_LAGUNAB), /* CL Laguna 3DA*/
+	{ 0, }
+};
+MODULE_DEVICE_TABLE(pci, cirrusfb_pci_table);
+#undef CHIP
+#endif /* CONFIG_PCI */
+
+#ifdef CONFIG_ZORRO
+struct zorrocl {
+	enum cirrus_board type;	/* Board type */
+	u32 regoffset;		/* Offset of registers in first Zorro device */
+	u32 ramsize;		/* Size of video RAM in first Zorro device */
+				/* If zero, use autoprobe on RAM device */
+	u32 ramoffset;		/* Offset of video RAM in first Zorro device */
+	zorro_id ramid;		/* Zorro ID of RAM device */
+	zorro_id ramid2;	/* Zorro ID of optional second RAM device */
+};
+
+static const struct zorrocl zcl_sd64 = {
+	.type		= BT_SD64,
+	.ramid		= ZORRO_PROD_HELFRICH_SD64_RAM,
+};
+
+static const struct zorrocl zcl_piccolo = {
+	.type		= BT_PICCOLO,
+	.ramid		= ZORRO_PROD_HELFRICH_PICCOLO_RAM,
+};
+
+static const struct zorrocl zcl_picasso = {
+	.type		= BT_PICASSO,
+	.ramid		= ZORRO_PROD_VILLAGE_TRONIC_PICASSO_II_II_PLUS_RAM,
+};
+
+static const struct zorrocl zcl_spectrum = {
+	.type		= BT_SPECTRUM,
+	.ramid		= ZORRO_PROD_GVP_EGS_28_24_SPECTRUM_RAM,
+};
+
+static const struct zorrocl zcl_picasso4_z3 = {
+	.type		= BT_PICASSO4,
+	.regoffset	= 0x00600000,
+	.ramsize	= 4 * MB_,
+	.ramoffset	= 0x01000000,	/* 0x02000000 for 64 MiB boards */
+};
+
+static const struct zorrocl zcl_picasso4_z2 = {
+	.type		= BT_PICASSO4,
+	.regoffset	= 0x10000,
+	.ramid		= ZORRO_PROD_VILLAGE_TRONIC_PICASSO_IV_Z2_RAM1,
+	.ramid2		= ZORRO_PROD_VILLAGE_TRONIC_PICASSO_IV_Z2_RAM2,
+};
+
+
+static const struct zorro_device_id cirrusfb_zorro_table[] = {
+	{
+		.id		= ZORRO_PROD_HELFRICH_SD64_REG,
+		.driver_data	= (unsigned long)&zcl_sd64,
+	}, {
+		.id		= ZORRO_PROD_HELFRICH_PICCOLO_REG,
+		.driver_data	= (unsigned long)&zcl_piccolo,
+	}, {
+		.id	= ZORRO_PROD_VILLAGE_TRONIC_PICASSO_II_II_PLUS_REG,
+		.driver_data	= (unsigned long)&zcl_picasso,
+	}, {
+		.id		= ZORRO_PROD_GVP_EGS_28_24_SPECTRUM_REG,
+		.driver_data	= (unsigned long)&zcl_spectrum,
+	}, {
+		.id		= ZORRO_PROD_VILLAGE_TRONIC_PICASSO_IV_Z3,
+		.driver_data	= (unsigned long)&zcl_picasso4_z3,
+	}, {
+		.id		= ZORRO_PROD_VILLAGE_TRONIC_PICASSO_IV_Z2_REG,
+		.driver_data	= (unsigned long)&zcl_picasso4_z2,
+	},
+	{ 0 }
+};
+MODULE_DEVICE_TABLE(zorro, cirrusfb_zorro_table);
+#endif /* CONFIG_ZORRO */
+
+#ifdef CIRRUSFB_DEBUG
+enum cirrusfb_dbg_reg_class {
+	CRT,
+	SEQ
+};
+#endif		/* CIRRUSFB_DEBUG */
+
+/* info about board */
+struct cirrusfb_info {
+	u8 __iomem *regbase;
+	u8 __iomem *laguna_mmio;
+	enum cirrus_board btype;
+	unsigned char SFR;	/* Shadow of special function register */
+
+	int multiplexing;
+	int doubleVCLK;
+	int blank_mode;
+	u32 pseudo_palette[16];
+
+	void (*unmap)(struct fb_info *info);
+};
+
+static bool noaccel;
+static char *mode_option = "640x480@60";
+
+/****************************************************************************/
+/**** BEGIN PROTOTYPES ******************************************************/
+
+/*--- Interface used by the world ------------------------------------------*/
+static int cirrusfb_pan_display(struct fb_var_screeninfo *var,
+				struct fb_info *info);
+
+/*--- Internal routines ----------------------------------------------------*/
+static void init_vgachip(struct fb_info *info);
+static void switch_monitor(struct cirrusfb_info *cinfo, int on);
+static void WGen(const struct cirrusfb_info *cinfo,
+		 int regnum, unsigned char val);
+static unsigned char RGen(const struct cirrusfb_info *cinfo, int regnum);
+static void AttrOn(const struct cirrusfb_info *cinfo);
+static void WHDR(const struct cirrusfb_info *cinfo, unsigned char val);
+static void WSFR(struct cirrusfb_info *cinfo, unsigned char val);
+static void WSFR2(struct cirrusfb_info *cinfo, unsigned char val);
+static void WClut(struct cirrusfb_info *cinfo, unsigned char regnum,
+		  unsigned char red, unsigned char green, unsigned char blue);
+#if 0
+static void RClut(struct cirrusfb_info *cinfo, unsigned char regnum,
+		  unsigned char *red, unsigned char *green,
+		  unsigned char *blue);
+#endif
+static void cirrusfb_WaitBLT(u8 __iomem *regbase);
+static void cirrusfb_BitBLT(u8 __iomem *regbase, int bits_per_pixel,
+			    u_short curx, u_short cury,
+			    u_short destx, u_short desty,
+			    u_short width, u_short height,
+			    u_short line_length);
+static void cirrusfb_RectFill(u8 __iomem *regbase, int bits_per_pixel,
+			      u_short x, u_short y,
+			      u_short width, u_short height,
+			      u32 fg_color, u32 bg_color,
+			      u_short line_length, u_char blitmode);
+
+static void bestclock(long freq, int *nom, int *den, int *div);
+
+#ifdef CIRRUSFB_DEBUG
+static void cirrusfb_dbg_reg_dump(struct fb_info *info, caddr_t regbase);
+static void cirrusfb_dbg_print_regs(struct fb_info *info,
+				    caddr_t regbase,
+				    enum cirrusfb_dbg_reg_class reg_class, ...);
+#endif /* CIRRUSFB_DEBUG */
+
+/*** END   PROTOTYPES ********************************************************/
+/*****************************************************************************/
+/*** BEGIN Interface Used by the World ***************************************/
+
+static inline int is_laguna(const struct cirrusfb_info *cinfo)
+{
+	return cinfo->btype == BT_LAGUNA || cinfo->btype == BT_LAGUNAB;
+}
+
+static int opencount;
+
+/*--- Open /dev/fbx ---------------------------------------------------------*/
+static int cirrusfb_open(struct fb_info *info, int user)
+{
+	if (opencount++ == 0)
+		switch_monitor(info->par, 1);
+	return 0;
+}
+
+/*--- Close /dev/fbx --------------------------------------------------------*/
+static int cirrusfb_release(struct fb_info *info, int user)
+{
+	if (--opencount == 0)
+		switch_monitor(info->par, 0);
+	return 0;
+}
+
+/**** END   Interface used by the World *************************************/
+/****************************************************************************/
+/**** BEGIN Hardware specific Routines **************************************/
+
+/* Check if the MCLK is not a better clock source */
+static int cirrusfb_check_mclk(struct fb_info *info, long freq)
+{
+	struct cirrusfb_info *cinfo = info->par;
+	long mclk = vga_rseq(cinfo->regbase, CL_SEQR1F) & 0x3f;
+
+	/* Read MCLK value */
+	mclk = (14318 * mclk) >> 3;
+	dev_dbg(info->device, "Read MCLK of %ld kHz\n", mclk);
+
+	/* Determine if we should use MCLK instead of VCLK, and if so, what we
+	 * should divide it by to get VCLK
+	 */
+
+	if (abs(freq - mclk) < 250) {
+		dev_dbg(info->device, "Using VCLK = MCLK\n");
+		return 1;
+	} else if (abs(freq - (mclk / 2)) < 250) {
+		dev_dbg(info->device, "Using VCLK = MCLK/2\n");
+		return 2;
+	}
+
+	return 0;
+}
+
+static int cirrusfb_check_pixclock(struct fb_var_screeninfo *var,
+				   struct fb_info *info)
+{
+	long freq;
+	long maxclock;
+	struct cirrusfb_info *cinfo = info->par;
+	unsigned maxclockidx = var->bits_per_pixel >> 3;
+
+	/* convert from ps to kHz */
+	freq = PICOS2KHZ(var->pixclock ? : 1);
+
+	maxclock = cirrusfb_board_info[cinfo->btype].maxclock[maxclockidx];
+	cinfo->multiplexing = 0;
+
+	/* If the frequency is greater than we can support, we might be able
+	 * to use multiplexing for the video mode */
+	if (freq > maxclock) {
+		var->pixclock = KHZ2PICOS(maxclock);
+
+		while ((freq = PICOS2KHZ(var->pixclock)) > maxclock)
+			var->pixclock++;
+	}
+	dev_dbg(info->device, "desired pixclock: %ld kHz\n", freq);
+
+	/*
+	 * Additional constraint: 8bpp uses DAC clock doubling to allow maximum
+	 * pixel clock
+	 */
+	if (var->bits_per_pixel == 8) {
+		switch (cinfo->btype) {
+		case BT_ALPINE:
+		case BT_SD64:
+		case BT_PICASSO4:
+			if (freq > 85500)
+				cinfo->multiplexing = 1;
+			break;
+		case BT_GD5480:
+			if (freq > 135100)
+				cinfo->multiplexing = 1;
+			break;
+
+		default:
+			break;
+		}
+	}
+
+	/* If we have a 1MB 5434, we need to put ourselves in a mode where
+	 * the VCLK is double the pixel clock. */
+	cinfo->doubleVCLK = 0;
+	if (cinfo->btype == BT_SD64 && info->fix.smem_len <= MB_ &&
+	    var->bits_per_pixel == 16) {
+		cinfo->doubleVCLK = 1;
+	}
+
+	return 0;
+}
+
+static int cirrusfb_check_var(struct fb_var_screeninfo *var,
+			      struct fb_info *info)
+{
+	int yres;
+	/* memory size in pixels */
+	unsigned int pixels;
+	struct cirrusfb_info *cinfo = info->par;
+
+	switch (var->bits_per_pixel) {
+	case 1:
+		var->red.offset = 0;
+		var->red.length = 1;
+		var->green = var->red;
+		var->blue = var->red;
+		break;
+
+	case 8:
+		var->red.offset = 0;
+		var->red.length = 8;
+		var->green = var->red;
+		var->blue = var->red;
+		break;
+
+	case 16:
+		var->red.offset = 11;
+		var->green.offset = 5;
+		var->blue.offset = 0;
+		var->red.length = 5;
+		var->green.length = 6;
+		var->blue.length = 5;
+		break;
+
+	case 24:
+		var->red.offset = 16;
+		var->green.offset = 8;
+		var->blue.offset = 0;
+		var->red.length = 8;
+		var->green.length = 8;
+		var->blue.length = 8;
+		break;
+
+	default:
+		dev_dbg(info->device,
+			"Unsupported bpp size: %d\n", var->bits_per_pixel);
+		return -EINVAL;
+	}
+
+	pixels = info->screen_size * 8 / var->bits_per_pixel;
+	if (var->xres_virtual < var->xres)
+		var->xres_virtual = var->xres;
+	/* use highest possible virtual resolution */
+	if (var->yres_virtual == -1) {
+		var->yres_virtual = pixels / var->xres_virtual;
+
+		dev_info(info->device,
+			 "virtual resolution set to maximum of %dx%d\n",
+			 var->xres_virtual, var->yres_virtual);
+	}
+	if (var->yres_virtual < var->yres)
+		var->yres_virtual = var->yres;
+
+	if (var->xres_virtual * var->yres_virtual > pixels) {
+		dev_err(info->device, "mode %dx%dx%d rejected... "
+		      "virtual resolution too high to fit into video memory!\n",
+			var->xres_virtual, var->yres_virtual,
+			var->bits_per_pixel);
+		return -EINVAL;
+	}
+
+	/* truncate xoffset and yoffset to maximum if too high */
+	if (var->xoffset > var->xres_virtual - var->xres)
+		var->xoffset = var->xres_virtual - var->xres - 1;
+	if (var->yoffset > var->yres_virtual - var->yres)
+		var->yoffset = var->yres_virtual - var->yres - 1;
+
+	var->red.msb_right =
+	    var->green.msb_right =
+	    var->blue.msb_right =
+	    var->transp.offset =
+	    var->transp.length =
+	    var->transp.msb_right = 0;
+
+	yres = var->yres;
+	if (var->vmode & FB_VMODE_DOUBLE)
+		yres *= 2;
+	else if (var->vmode & FB_VMODE_INTERLACED)
+		yres = (yres + 1) / 2;
+
+	if (yres >= 1280) {
+		dev_err(info->device, "ERROR: VerticalTotal >= 1280; "
+			"special treatment required! (TODO)\n");
+		return -EINVAL;
+	}
+
+	if (cirrusfb_check_pixclock(var, info))
+		return -EINVAL;
+
+	if (!is_laguna(cinfo))
+		var->accel_flags = FB_ACCELF_TEXT;
+
+	return 0;
+}
+
+static void cirrusfb_set_mclk_as_source(const struct fb_info *info, int div)
+{
+	struct cirrusfb_info *cinfo = info->par;
+	unsigned char old1f, old1e;
+
+	assert(cinfo != NULL);
+	old1f = vga_rseq(cinfo->regbase, CL_SEQR1F) & ~0x40;
+
+	if (div) {
+		dev_dbg(info->device, "Set %s as pixclock source.\n",
+			(div == 2) ? "MCLK/2" : "MCLK");
+		old1f |= 0x40;
+		old1e = vga_rseq(cinfo->regbase, CL_SEQR1E) & ~0x1;
+		if (div == 2)
+			old1e |= 1;
+
+		vga_wseq(cinfo->regbase, CL_SEQR1E, old1e);
+	}
+	vga_wseq(cinfo->regbase, CL_SEQR1F, old1f);
+}
+
+/*************************************************************************
+	cirrusfb_set_par_foo()
+
+	actually writes the values for a new video mode into the hardware,
+**************************************************************************/
+static int cirrusfb_set_par_foo(struct fb_info *info)
+{
+	struct cirrusfb_info *cinfo = info->par;
+	struct fb_var_screeninfo *var = &info->var;
+	u8 __iomem *regbase = cinfo->regbase;
+	unsigned char tmp;
+	int pitch;
+	const struct cirrusfb_board_info_rec *bi;
+	int hdispend, hsyncstart, hsyncend, htotal;
+	int yres, vdispend, vsyncstart, vsyncend, vtotal;
+	long freq;
+	int nom, den, div;
+	unsigned int control = 0, format = 0, threshold = 0;
+
+	dev_dbg(info->device, "Requested mode: %dx%dx%d\n",
+	       var->xres, var->yres, var->bits_per_pixel);
+
+	switch (var->bits_per_pixel) {
+	case 1:
+		info->fix.line_length = var->xres_virtual / 8;
+		info->fix.visual = FB_VISUAL_MONO10;
+		break;
+
+	case 8:
+		info->fix.line_length = var->xres_virtual;
+		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
+		break;
+
+	case 16:
+	case 24:
+		info->fix.line_length = var->xres_virtual *
+					var->bits_per_pixel >> 3;
+		info->fix.visual = FB_VISUAL_TRUECOLOR;
+		break;
+	}
+	info->fix.type = FB_TYPE_PACKED_PIXELS;
+
+	init_vgachip(info);
+
+	bi = &cirrusfb_board_info[cinfo->btype];
+
+	hsyncstart = var->xres + var->right_margin;
+	hsyncend = hsyncstart + var->hsync_len;
+	htotal = (hsyncend + var->left_margin) / 8;
+	hdispend = var->xres / 8;
+	hsyncstart = hsyncstart / 8;
+	hsyncend = hsyncend / 8;
+
+	vdispend = var->yres;
+	vsyncstart = vdispend + var->lower_margin;
+	vsyncend = vsyncstart + var->vsync_len;
+	vtotal = vsyncend + var->upper_margin;
+
+	if (var->vmode & FB_VMODE_DOUBLE) {
+		vdispend *= 2;
+		vsyncstart *= 2;
+		vsyncend *= 2;
+		vtotal *= 2;
+	} else if (var->vmode & FB_VMODE_INTERLACED) {
+		vdispend = (vdispend + 1) / 2;
+		vsyncstart = (vsyncstart + 1) / 2;
+		vsyncend = (vsyncend + 1) / 2;
+		vtotal = (vtotal + 1) / 2;
+	}
+	yres = vdispend;
+	if (yres >= 1024) {
+		vtotal /= 2;
+		vsyncstart /= 2;
+		vsyncend /= 2;
+		vdispend /= 2;
+	}
+
+	vdispend -= 1;
+	vsyncstart -= 1;
+	vsyncend -= 1;
+	vtotal -= 2;
+
+	if (cinfo->multiplexing) {
+		htotal /= 2;
+		hsyncstart /= 2;
+		hsyncend /= 2;
+		hdispend /= 2;
+	}
+
+	htotal -= 5;
+	hdispend -= 1;
+	hsyncstart += 1;
+	hsyncend += 1;
+
+	/* unlock register VGA_CRTC_H_TOTAL..CRT7 */
+	vga_wcrt(regbase, VGA_CRTC_V_SYNC_END, 0x20);	/* previously: 0x00) */
+
+	/* if debugging is enabled, all parameters get output before writing */
+	dev_dbg(info->device, "CRT0: %d\n", htotal);
+	vga_wcrt(regbase, VGA_CRTC_H_TOTAL, htotal);
+
+	dev_dbg(info->device, "CRT1: %d\n", hdispend);
+	vga_wcrt(regbase, VGA_CRTC_H_DISP, hdispend);
+
+	dev_dbg(info->device, "CRT2: %d\n", var->xres / 8);
+	vga_wcrt(regbase, VGA_CRTC_H_BLANK_START, var->xres / 8);
+
+	/*  + 128: Compatible read */
+	dev_dbg(info->device, "CRT3: 128+%d\n", (htotal + 5) % 32);
+	vga_wcrt(regbase, VGA_CRTC_H_BLANK_END,
+		 128 + ((htotal + 5) % 32));
+
+	dev_dbg(info->device, "CRT4: %d\n", hsyncstart);
+	vga_wcrt(regbase, VGA_CRTC_H_SYNC_START, hsyncstart);
+
+	tmp = hsyncend % 32;
+	if ((htotal + 5) & 32)
+		tmp += 128;
+	dev_dbg(info->device, "CRT5: %d\n", tmp);
+	vga_wcrt(regbase, VGA_CRTC_H_SYNC_END, tmp);
+
+	dev_dbg(info->device, "CRT6: %d\n", vtotal & 0xff);
+	vga_wcrt(regbase, VGA_CRTC_V_TOTAL, vtotal & 0xff);
+
+	tmp = 16;		/* LineCompare bit #9 */
+	if (vtotal & 256)
+		tmp |= 1;
+	if (vdispend & 256)
+		tmp |= 2;
+	if (vsyncstart & 256)
+		tmp |= 4;
+	if ((vdispend + 1) & 256)
+		tmp |= 8;
+	if (vtotal & 512)
+		tmp |= 32;
+	if (vdispend & 512)
+		tmp |= 64;
+	if (vsyncstart & 512)
+		tmp |= 128;
+	dev_dbg(info->device, "CRT7: %d\n", tmp);
+	vga_wcrt(regbase, VGA_CRTC_OVERFLOW, tmp);
+
+	tmp = 0x40;		/* LineCompare bit #8 */
+	if ((vdispend + 1) & 512)
+		tmp |= 0x20;
+	if (var->vmode & FB_VMODE_DOUBLE)
+		tmp |= 0x80;
+	dev_dbg(info->device, "CRT9: %d\n", tmp);
+	vga_wcrt(regbase, VGA_CRTC_MAX_SCAN, tmp);
+
+	dev_dbg(info->device, "CRT10: %d\n", vsyncstart & 0xff);
+	vga_wcrt(regbase, VGA_CRTC_V_SYNC_START, vsyncstart & 0xff);
+
+	dev_dbg(info->device, "CRT11: 64+32+%d\n", vsyncend % 16);
+	vga_wcrt(regbase, VGA_CRTC_V_SYNC_END, vsyncend % 16 + 64 + 32);
+
+	dev_dbg(info->device, "CRT12: %d\n", vdispend & 0xff);
+	vga_wcrt(regbase, VGA_CRTC_V_DISP_END, vdispend & 0xff);
+
+	dev_dbg(info->device, "CRT15: %d\n", (vdispend + 1) & 0xff);
+	vga_wcrt(regbase, VGA_CRTC_V_BLANK_START, (vdispend + 1) & 0xff);
+
+	dev_dbg(info->device, "CRT16: %d\n", vtotal & 0xff);
+	vga_wcrt(regbase, VGA_CRTC_V_BLANK_END, vtotal & 0xff);
+
+	dev_dbg(info->device, "CRT18: 0xff\n");
+	vga_wcrt(regbase, VGA_CRTC_LINE_COMPARE, 0xff);
+
+	tmp = 0;
+	if (var->vmode & FB_VMODE_INTERLACED)
+		tmp |= 1;
+	if ((htotal + 5) & 64)
+		tmp |= 16;
+	if ((htotal + 5) & 128)
+		tmp |= 32;
+	if (vtotal & 256)
+		tmp |= 64;
+	if (vtotal & 512)
+		tmp |= 128;
+
+	dev_dbg(info->device, "CRT1a: %d\n", tmp);
+	vga_wcrt(regbase, CL_CRT1A, tmp);
+
+	freq = PICOS2KHZ(var->pixclock);
+	if (var->bits_per_pixel == 24)
+		if (cinfo->btype == BT_ALPINE || cinfo->btype == BT_SD64)
+			freq *= 3;
+	if (cinfo->multiplexing)
+		freq /= 2;
+	if (cinfo->doubleVCLK)
+		freq *= 2;
+
+	bestclock(freq, &nom, &den, &div);
+
+	dev_dbg(info->device, "VCLK freq: %ld kHz  nom: %d  den: %d  div: %d\n",
+		freq, nom, den, div);
+
+	/* set VCLK0 */
+	/* hardware RefClock: 14.31818 MHz */
+	/* formula: VClk = (OSC * N) / (D * (1+P)) */
+	/* Example: VClk = (14.31818 * 91) / (23 * (1+1)) = 28.325 MHz */
+
+	if (cinfo->btype == BT_ALPINE || cinfo->btype == BT_PICASSO4 ||
+	    cinfo->btype == BT_SD64) {
+		/* if freq is close to mclk or mclk/2 select mclk
+		 * as clock source
+		 */
+		int divMCLK = cirrusfb_check_mclk(info, freq);
+		if (divMCLK)
+			nom = 0;
+		cirrusfb_set_mclk_as_source(info, divMCLK);
+	}
+	if (is_laguna(cinfo)) {
+		long pcifc = fb_readl(cinfo->laguna_mmio + 0x3fc);
+		unsigned char tile = fb_readb(cinfo->laguna_mmio + 0x407);
+		unsigned short tile_control;
+
+		if (cinfo->btype == BT_LAGUNAB) {
+			tile_control = fb_readw(cinfo->laguna_mmio + 0x2c4);
+			tile_control &= ~0x80;
+			fb_writew(tile_control, cinfo->laguna_mmio + 0x2c4);
+		}
+
+		fb_writel(pcifc | 0x10000000l, cinfo->laguna_mmio + 0x3fc);
+		fb_writeb(tile & 0x3f, cinfo->laguna_mmio + 0x407);
+		control = fb_readw(cinfo->laguna_mmio + 0x402);
+		threshold = fb_readw(cinfo->laguna_mmio + 0xea);
+		control &= ~0x6800;
+		format = 0;
+		threshold &= 0xffc0 & 0x3fbf;
+	}
+	if (nom) {
+		tmp = den << 1;
+		if (div != 0)
+			tmp |= 1;
+		/* 6 bit denom; ONLY 5434!!! (bugged me 10 days) */
+		if ((cinfo->btype == BT_SD64) ||
+		    (cinfo->btype == BT_ALPINE) ||
+		    (cinfo->btype == BT_GD5480))
+			tmp |= 0x80;
+
+		/* Laguna chipset has reversed clock registers */
+		if (is_laguna(cinfo)) {
+			vga_wseq(regbase, CL_SEQRE, tmp);
+			vga_wseq(regbase, CL_SEQR1E, nom);
+		} else {
+			vga_wseq(regbase, CL_SEQRE, nom);
+			vga_wseq(regbase, CL_SEQR1E, tmp);
+		}
+	}
+
+	if (yres >= 1024)
+		/* 1280x1024 */
+		vga_wcrt(regbase, VGA_CRTC_MODE, 0xc7);
+	else
+		/* mode control: VGA_CRTC_START_HI enable, ROTATE(?), 16bit
+		 * address wrap, no compat. */
+		vga_wcrt(regbase, VGA_CRTC_MODE, 0xc3);
+
+	/* don't know if it would hurt to also program this if no interlaced */
+	/* mode is used, but I feel better this way.. :-) */
+	if (var->vmode & FB_VMODE_INTERLACED)
+		vga_wcrt(regbase, VGA_CRTC_REGS, htotal / 2);
+	else
+		vga_wcrt(regbase, VGA_CRTC_REGS, 0x00);	/* interlace control */
+
+	/* adjust horizontal/vertical sync type (low/high), use VCLK3 */
+	/* enable display memory & CRTC I/O address for color mode */
+	tmp = 0x03 | 0xc;
+	if (var->sync & FB_SYNC_HOR_HIGH_ACT)
+		tmp |= 0x40;
+	if (var->sync & FB_SYNC_VERT_HIGH_ACT)
+		tmp |= 0x80;
+	WGen(cinfo, VGA_MIS_W, tmp);
+
+	/* text cursor on and start line */
+	vga_wcrt(regbase, VGA_CRTC_CURSOR_START, 0);
+	/* text cursor end line */
+	vga_wcrt(regbase, VGA_CRTC_CURSOR_END, 31);
+
+	/******************************************************
+	 *
+	 * 1 bpp
+	 *
+	 */
+
+	/* programming for different color depths */
+	if (var->bits_per_pixel == 1) {
+		dev_dbg(info->device, "preparing for 1 bit deep display\n");
+		vga_wgfx(regbase, VGA_GFX_MODE, 0);	/* mode register */
+
+		/* SR07 */
+		switch (cinfo->btype) {
+		case BT_SD64:
+		case BT_PICCOLO:
+		case BT_PICASSO:
+		case BT_SPECTRUM:
+		case BT_PICASSO4:
+		case BT_ALPINE:
+		case BT_GD5480:
+			vga_wseq(regbase, CL_SEQR7,
+				 cinfo->multiplexing ?
+					bi->sr07_1bpp_mux : bi->sr07_1bpp);
+			break;
+
+		case BT_LAGUNA:
+		case BT_LAGUNAB:
+			vga_wseq(regbase, CL_SEQR7,
+				vga_rseq(regbase, CL_SEQR7) & ~0x01);
+			break;
+
+		default:
+			dev_warn(info->device, "unknown Board\n");
+			break;
+		}
+
+		/* Extended Sequencer Mode */
+		switch (cinfo->btype) {
+
+		case BT_PICCOLO:
+		case BT_SPECTRUM:
+			/* evtl d0 bei 1 bit? avoid FIFO underruns..? */
+			vga_wseq(regbase, CL_SEQRF, 0xb0);
+			break;
+
+		case BT_PICASSO:
+			/* ## vorher d0 avoid FIFO underruns..? */
+			vga_wseq(regbase, CL_SEQRF, 0xd0);
+			break;
+
+		case BT_SD64:
+		case BT_PICASSO4:
+		case BT_ALPINE:
+		case BT_GD5480:
+		case BT_LAGUNA:
+		case BT_LAGUNAB:
+			/* do nothing */
+			break;
+
+		default:
+			dev_warn(info->device, "unknown Board\n");
+			break;
+		}
+
+		/* pixel mask: pass-through for first plane */
+		WGen(cinfo, VGA_PEL_MSK, 0x01);
+		if (cinfo->multiplexing)
+			/* hidden dac reg: 1280x1024 */
+			WHDR(cinfo, 0x4a);
+		else
+			/* hidden dac: nothing */
+			WHDR(cinfo, 0);
+		/* memory mode: odd/even, ext. memory */
+		vga_wseq(regbase, VGA_SEQ_MEMORY_MODE, 0x06);
+		/* plane mask: only write to first plane */
+		vga_wseq(regbase, VGA_SEQ_PLANE_WRITE, 0x01);
+	}
+
+	/******************************************************
+	 *
+	 * 8 bpp
+	 *
+	 */
+
+	else if (var->bits_per_pixel == 8) {
+		dev_dbg(info->device, "preparing for 8 bit deep display\n");
+		switch (cinfo->btype) {
+		case BT_SD64:
+		case BT_PICCOLO:
+		case BT_PICASSO:
+		case BT_SPECTRUM:
+		case BT_PICASSO4:
+		case BT_ALPINE:
+		case BT_GD5480:
+			vga_wseq(regbase, CL_SEQR7,
+				  cinfo->multiplexing ?
+					bi->sr07_8bpp_mux : bi->sr07_8bpp);
+			break;
+
+		case BT_LAGUNA:
+		case BT_LAGUNAB:
+			vga_wseq(regbase, CL_SEQR7,
+				vga_rseq(regbase, CL_SEQR7) | 0x01);
+			threshold |= 0x10;
+			break;
+
+		default:
+			dev_warn(info->device, "unknown Board\n");
+			break;
+		}
+
+		switch (cinfo->btype) {
+		case BT_PICCOLO:
+		case BT_PICASSO:
+		case BT_SPECTRUM:
+			/* Fast Page-Mode writes */
+			vga_wseq(regbase, CL_SEQRF, 0xb0);
+			break;
+
+		case BT_PICASSO4:
+#ifdef CONFIG_ZORRO
+			/* ### INCOMPLETE!! */
+			vga_wseq(regbase, CL_SEQRF, 0xb8);
+#endif
+		case BT_ALPINE:
+		case BT_SD64:
+		case BT_GD5480:
+		case BT_LAGUNA:
+		case BT_LAGUNAB:
+			/* do nothing */
+			break;
+
+		default:
+			dev_warn(info->device, "unknown board\n");
+			break;
+		}
+
+		/* mode register: 256 color mode */
+		vga_wgfx(regbase, VGA_GFX_MODE, 64);
+		if (cinfo->multiplexing)
+			/* hidden dac reg: 1280x1024 */
+			WHDR(cinfo, 0x4a);
+		else
+			/* hidden dac: nothing */
+			WHDR(cinfo, 0);
+	}
+
+	/******************************************************
+	 *
+	 * 16 bpp
+	 *
+	 */
+
+	else if (var->bits_per_pixel == 16) {
+		dev_dbg(info->device, "preparing for 16 bit deep display\n");
+		switch (cinfo->btype) {
+		case BT_PICCOLO:
+		case BT_SPECTRUM:
+			vga_wseq(regbase, CL_SEQR7, 0x87);
+			/* Fast Page-Mode writes */
+			vga_wseq(regbase, CL_SEQRF, 0xb0);
+			break;
+
+		case BT_PICASSO:
+			vga_wseq(regbase, CL_SEQR7, 0x27);
+			/* Fast Page-Mode writes */
+			vga_wseq(regbase, CL_SEQRF, 0xb0);
+			break;
+
+		case BT_SD64:
+		case BT_PICASSO4:
+		case BT_ALPINE:
+			/* Extended Sequencer Mode: 256c col. mode */
+			vga_wseq(regbase, CL_SEQR7,
+					cinfo->doubleVCLK ? 0xa3 : 0xa7);
+			break;
+
+		case BT_GD5480:
+			vga_wseq(regbase, CL_SEQR7, 0x17);
+			/* We already set SRF and SR1F */
+			break;
+
+		case BT_LAGUNA:
+		case BT_LAGUNAB:
+			vga_wseq(regbase, CL_SEQR7,
+				vga_rseq(regbase, CL_SEQR7) & ~0x01);
+			control |= 0x2000;
+			format |= 0x1400;
+			threshold |= 0x10;
+			break;
+
+		default:
+			dev_warn(info->device, "unknown Board\n");
+			break;
+		}
+
+		/* mode register: 256 color mode */
+		vga_wgfx(regbase, VGA_GFX_MODE, 64);
+#ifdef CONFIG_PCI
+		WHDR(cinfo, cinfo->doubleVCLK ? 0xe1 : 0xc1);
+#elif defined(CONFIG_ZORRO)
+		/* FIXME: CONFIG_PCI and CONFIG_ZORRO may be defined both */
+		WHDR(cinfo, 0xa0);	/* hidden dac reg: nothing special */
+#endif
+	}
+
+	/******************************************************
+	 *
+	 * 24 bpp
+	 *
+	 */
+
+	else if (var->bits_per_pixel == 24) {
+		dev_dbg(info->device, "preparing for 24 bit deep display\n");
+		switch (cinfo->btype) {
+		case BT_PICCOLO:
+		case BT_SPECTRUM:
+			vga_wseq(regbase, CL_SEQR7, 0x85);
+			/* Fast Page-Mode writes */
+			vga_wseq(regbase, CL_SEQRF, 0xb0);
+			break;
+
+		case BT_PICASSO:
+			vga_wseq(regbase, CL_SEQR7, 0x25);
+			/* Fast Page-Mode writes */
+			vga_wseq(regbase, CL_SEQRF, 0xb0);
+			break;
+
+		case BT_SD64:
+		case BT_PICASSO4:
+		case BT_ALPINE:
+			/* Extended Sequencer Mode: 256c col. mode */
+			vga_wseq(regbase, CL_SEQR7, 0xa5);
+			break;
+
+		case BT_GD5480:
+			vga_wseq(regbase, CL_SEQR7, 0x15);
+			/* We already set SRF and SR1F */
+			break;
+
+		case BT_LAGUNA:
+		case BT_LAGUNAB:
+			vga_wseq(regbase, CL_SEQR7,
+				vga_rseq(regbase, CL_SEQR7) & ~0x01);
+			control |= 0x4000;
+			format |= 0x2400;
+			threshold |= 0x20;
+			break;
+
+		default:
+			dev_warn(info->device, "unknown Board\n");
+			break;
+		}
+
+		/* mode register: 256 color mode */
+		vga_wgfx(regbase, VGA_GFX_MODE, 64);
+		/* hidden dac reg: 8-8-8 mode (24 or 32) */
+		WHDR(cinfo, 0xc5);
+	}
+
+	/******************************************************
+	 *
+	 * unknown/unsupported bpp
+	 *
+	 */
+
+	else
+		dev_err(info->device,
+			"What's this? requested color depth == %d.\n",
+			var->bits_per_pixel);
+
+	pitch = info->fix.line_length >> 3;
+	vga_wcrt(regbase, VGA_CRTC_OFFSET, pitch & 0xff);
+	tmp = 0x22;
+	if (pitch & 0x100)
+		tmp |= 0x10;	/* offset overflow bit */
+
+	/* screen start addr #16-18, fastpagemode cycles */
+	vga_wcrt(regbase, CL_CRT1B, tmp);
+
+	/* screen start address bit 19 */
+	if (cirrusfb_board_info[cinfo->btype].scrn_start_bit19)
+		vga_wcrt(regbase, CL_CRT1D, (pitch >> 9) & 1);
+
+	if (is_laguna(cinfo)) {
+		tmp = 0;
+		if ((htotal + 5) & 256)
+			tmp |= 128;
+		if (hdispend & 256)
+			tmp |= 64;
+		if (hsyncstart & 256)
+			tmp |= 48;
+		if (vtotal & 1024)
+			tmp |= 8;
+		if (vdispend & 1024)
+			tmp |= 4;
+		if (vsyncstart & 1024)
+			tmp |= 3;
+
+		vga_wcrt(regbase, CL_CRT1E, tmp);
+		dev_dbg(info->device, "CRT1e: %d\n", tmp);
+	}
+
+	/* pixel panning */
+	vga_wattr(regbase, CL_AR33, 0);
+
+	/* [ EGS: SetOffset(); ] */
+	/* From SetOffset(): Turn on VideoEnable bit in Attribute controller */
+	AttrOn(cinfo);
+
+	if (is_laguna(cinfo)) {
+		/* no tiles */
+		fb_writew(control | 0x1000, cinfo->laguna_mmio + 0x402);
+		fb_writew(format, cinfo->laguna_mmio + 0xc0);
+		fb_writew(threshold, cinfo->laguna_mmio + 0xea);
+	}
+	/* finally, turn on everything - turn off "FullBandwidth" bit */
+	/* also, set "DotClock%2" bit where requested */
+	tmp = 0x01;
+
+/*** FB_VMODE_CLOCK_HALVE in linux/fb.h not defined anymore ?
+    if (var->vmode & FB_VMODE_CLOCK_HALVE)
+	tmp |= 0x08;
+*/
+
+	vga_wseq(regbase, VGA_SEQ_CLOCK_MODE, tmp);
+	dev_dbg(info->device, "CL_SEQR1: %d\n", tmp);
+
+#ifdef CIRRUSFB_DEBUG
+	cirrusfb_dbg_reg_dump(info, NULL);
+#endif
+
+	return 0;
+}
+
+/* for some reason incomprehensible to me, cirrusfb requires that you write
+ * the registers twice for the settings to take..grr. -dte */
+static int cirrusfb_set_par(struct fb_info *info)
+{
+	cirrusfb_set_par_foo(info);
+	return cirrusfb_set_par_foo(info);
+}
+
+static int cirrusfb_setcolreg(unsigned regno, unsigned red, unsigned green,
+			      unsigned blue, unsigned transp,
+			      struct fb_info *info)
+{
+	struct cirrusfb_info *cinfo = info->par;
+
+	if (regno > 255)
+		return -EINVAL;
+
+	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
+		u32 v;
+		red >>= (16 - info->var.red.length);
+		green >>= (16 - info->var.green.length);
+		blue >>= (16 - info->var.blue.length);
+
+		if (regno >= 16)
+			return 1;
+		v = (red << info->var.red.offset) |
+		    (green << info->var.green.offset) |
+		    (blue << info->var.blue.offset);
+
+		cinfo->pseudo_palette[regno] = v;
+		return 0;
+	}
+
+	if (info->var.bits_per_pixel == 8)
+		WClut(cinfo, regno, red >> 10, green >> 10, blue >> 10);
+
+	return 0;
+
+}
+
+/*************************************************************************
+	cirrusfb_pan_display()
+
+	performs display panning - provided hardware permits this
+**************************************************************************/
+static int cirrusfb_pan_display(struct fb_var_screeninfo *var,
+				struct fb_info *info)
+{
+	int xoffset;
+	unsigned long base;
+	unsigned char tmp, xpix;
+	struct cirrusfb_info *cinfo = info->par;
+
+	/* no range checks for xoffset and yoffset,   */
+	/* as fb_pan_display has already done this */
+	if (var->vmode & FB_VMODE_YWRAP)
+		return -EINVAL;
+
+	xoffset = var->xoffset * info->var.bits_per_pixel / 8;
+
+	base = var->yoffset * info->fix.line_length + xoffset;
+
+	if (info->var.bits_per_pixel == 1) {
+		/* base is already correct */
+		xpix = (unsigned char) (var->xoffset % 8);
+	} else {
+		base /= 4;
+		xpix = (unsigned char) ((xoffset % 4) * 2);
+	}
+
+	if (!is_laguna(cinfo))
+		cirrusfb_WaitBLT(cinfo->regbase);
+
+	/* lower 8 + 8 bits of screen start address */
+	vga_wcrt(cinfo->regbase, VGA_CRTC_START_LO, base & 0xff);
+	vga_wcrt(cinfo->regbase, VGA_CRTC_START_HI, (base >> 8) & 0xff);
+
+	/* 0xf2 is %11110010, exclude tmp bits */
+	tmp = vga_rcrt(cinfo->regbase, CL_CRT1B) & 0xf2;
+	/* construct bits 16, 17 and 18 of screen start address */
+	if (base & 0x10000)
+		tmp |= 0x01;
+	if (base & 0x20000)
+		tmp |= 0x04;
+	if (base & 0x40000)
+		tmp |= 0x08;
+
+	vga_wcrt(cinfo->regbase, CL_CRT1B, tmp);
+
+	/* construct bit 19 of screen start address */
+	if (cirrusfb_board_info[cinfo->btype].scrn_start_bit19) {
+		tmp = vga_rcrt(cinfo->regbase, CL_CRT1D);
+		if (is_laguna(cinfo))
+			tmp = (tmp & ~0x18) | ((base >> 16) & 0x18);
+		else
+			tmp = (tmp & ~0x80) | ((base >> 12) & 0x80);
+		vga_wcrt(cinfo->regbase, CL_CRT1D, tmp);
+	}
+
+	/* write pixel panning value to AR33; this does not quite work in 8bpp
+	 *
+	 * ### Piccolo..? Will this work?
+	 */
+	if (info->var.bits_per_pixel == 1)
+		vga_wattr(cinfo->regbase, CL_AR33, xpix);
+
+	return 0;
+}
+
+static int cirrusfb_blank(int blank_mode, struct fb_info *info)
+{
+	/*
+	 * Blank the screen if blank_mode != 0, else unblank. If blank == NULL
+	 * then the caller blanks by setting the CLUT (Color Look Up Table)
+	 * to all black. Return 0 if blanking succeeded, != 0 if un-/blanking
+	 * failed due to e.g. a video mode which doesn't support it.
+	 * Implements VESA suspend and powerdown modes on hardware that
+	 * supports disabling hsync/vsync:
+	 *   blank_mode == 2: suspend vsync
+	 *   blank_mode == 3: suspend hsync
+	 *   blank_mode == 4: powerdown
+	 */
+	unsigned char val;
+	struct cirrusfb_info *cinfo = info->par;
+	int current_mode = cinfo->blank_mode;
+
+	dev_dbg(info->device, "ENTER, blank mode = %d\n", blank_mode);
+
+	if (info->state != FBINFO_STATE_RUNNING ||
+	    current_mode == blank_mode) {
+		dev_dbg(info->device, "EXIT, returning 0\n");
+		return 0;
+	}
+
+	/* Undo current */
+	if (current_mode == FB_BLANK_NORMAL ||
+	    current_mode == FB_BLANK_UNBLANK)
+		/* clear "FullBandwidth" bit */
+		val = 0;
+	else
+		/* set "FullBandwidth" bit */
+		val = 0x20;
+
+	val |= vga_rseq(cinfo->regbase, VGA_SEQ_CLOCK_MODE) & 0xdf;
+	vga_wseq(cinfo->regbase, VGA_SEQ_CLOCK_MODE, val);
+
+	switch (blank_mode) {
+	case FB_BLANK_UNBLANK:
+	case FB_BLANK_NORMAL:
+		val = 0x00;
+		break;
+	case FB_BLANK_VSYNC_SUSPEND:
+		val = 0x04;
+		break;
+	case FB_BLANK_HSYNC_SUSPEND:
+		val = 0x02;
+		break;
+	case FB_BLANK_POWERDOWN:
+		val = 0x06;
+		break;
+	default:
+		dev_dbg(info->device, "EXIT, returning 1\n");
+		return 1;
+	}
+
+	vga_wgfx(cinfo->regbase, CL_GRE, val);
+
+	cinfo->blank_mode = blank_mode;
+	dev_dbg(info->device, "EXIT, returning 0\n");
+
+	/* Let fbcon do a soft blank for us */
+	return (blank_mode == FB_BLANK_NORMAL) ? 1 : 0;
+}
+
+/**** END   Hardware specific Routines **************************************/
+/****************************************************************************/
+/**** BEGIN Internal Routines ***********************************************/
+
+static void init_vgachip(struct fb_info *info)
+{
+	struct cirrusfb_info *cinfo = info->par;
+	const struct cirrusfb_board_info_rec *bi;
+
+	assert(cinfo != NULL);
+
+	bi = &cirrusfb_board_info[cinfo->btype];
+
+	/* reset board globally */
+	switch (cinfo->btype) {
+	case BT_PICCOLO:
+		WSFR(cinfo, 0x01);
+		udelay(500);
+		WSFR(cinfo, 0x51);
+		udelay(500);
+		break;
+	case BT_PICASSO:
+		WSFR2(cinfo, 0xff);
+		udelay(500);
+		break;
+	case BT_SD64:
+	case BT_SPECTRUM:
+		WSFR(cinfo, 0x1f);
+		udelay(500);
+		WSFR(cinfo, 0x4f);
+		udelay(500);
+		break;
+	case BT_PICASSO4:
+		/* disable flickerfixer */
+		vga_wcrt(cinfo->regbase, CL_CRT51, 0x00);
+		mdelay(100);
+		/* mode */
+		vga_wgfx(cinfo->regbase, CL_GR31, 0x00);
+		fallthrough;
+	case BT_GD5480:
+		/* from Klaus' NetBSD driver: */
+		vga_wgfx(cinfo->regbase, CL_GR2F, 0x00);
+		fallthrough;
+	case BT_ALPINE:
+		/* put blitter into 542x compat */
+		vga_wgfx(cinfo->regbase, CL_GR33, 0x00);
+		break;
+
+	case BT_LAGUNA:
+	case BT_LAGUNAB:
+		/* Nothing to do to reset the board. */
+		break;
+
+	default:
+		dev_err(info->device, "Warning: Unknown board type\n");
+		break;
+	}
+
+	/* make sure RAM size set by this point */
+	assert(info->screen_size > 0);
+
+	/* the P4 is not fully initialized here; I rely on it having been */
+	/* inited under AmigaOS already, which seems to work just fine    */
+	/* (Klaus advised to do it this way)			      */
+
+	if (cinfo->btype != BT_PICASSO4) {
+		WGen(cinfo, CL_VSSM, 0x10);	/* EGS: 0x16 */
+		WGen(cinfo, CL_POS102, 0x01);
+		WGen(cinfo, CL_VSSM, 0x08);	/* EGS: 0x0e */
+
+		if (cinfo->btype != BT_SD64)
+			WGen(cinfo, CL_VSSM2, 0x01);
+
+		/* reset sequencer logic */
+		vga_wseq(cinfo->regbase, VGA_SEQ_RESET, 0x03);
+
+		/* FullBandwidth (video off) and 8/9 dot clock */
+		vga_wseq(cinfo->regbase, VGA_SEQ_CLOCK_MODE, 0x21);
+
+		/* "magic cookie" - doesn't make any sense to me.. */
+/*      vga_wgfx(cinfo->regbase, CL_GRA, 0xce);   */
+		/* unlock all extension registers */
+		vga_wseq(cinfo->regbase, CL_SEQR6, 0x12);
+
+		switch (cinfo->btype) {
+		case BT_GD5480:
+			vga_wseq(cinfo->regbase, CL_SEQRF, 0x98);
+			break;
+		case BT_ALPINE:
+		case BT_LAGUNA:
+		case BT_LAGUNAB:
+			break;
+		case BT_SD64:
+#ifdef CONFIG_ZORRO
+			vga_wseq(cinfo->regbase, CL_SEQRF, 0xb8);
+#endif
+			break;
+		default:
+			vga_wseq(cinfo->regbase, CL_SEQR16, 0x0f);
+			vga_wseq(cinfo->regbase, CL_SEQRF, 0xb0);
+			break;
+		}
+	}
+	/* plane mask: nothing */
+	vga_wseq(cinfo->regbase, VGA_SEQ_PLANE_WRITE, 0xff);
+	/* character map select: doesn't even matter in gx mode */
+	vga_wseq(cinfo->regbase, VGA_SEQ_CHARACTER_MAP, 0x00);
+	/* memory mode: chain4, ext. memory */
+	vga_wseq(cinfo->regbase, VGA_SEQ_MEMORY_MODE, 0x0a);
+
+	/* controller-internal base address of video memory */
+	if (bi->init_sr07)
+		vga_wseq(cinfo->regbase, CL_SEQR7, bi->sr07);
+
+	/*  vga_wseq(cinfo->regbase, CL_SEQR8, 0x00); */
+	/* EEPROM control: shouldn't be necessary to write to this at all.. */
+
+	/* graphics cursor X position (incomplete; position gives rem. 3 bits */
+	vga_wseq(cinfo->regbase, CL_SEQR10, 0x00);
+	/* graphics cursor Y position (..."... ) */
+	vga_wseq(cinfo->regbase, CL_SEQR11, 0x00);
+	/* graphics cursor attributes */
+	vga_wseq(cinfo->regbase, CL_SEQR12, 0x00);
+	/* graphics cursor pattern address */
+	vga_wseq(cinfo->regbase, CL_SEQR13, 0x00);
+
+	/* writing these on a P4 might give problems..  */
+	if (cinfo->btype != BT_PICASSO4) {
+		/* configuration readback and ext. color */
+		vga_wseq(cinfo->regbase, CL_SEQR17, 0x00);
+		/* signature generator */
+		vga_wseq(cinfo->regbase, CL_SEQR18, 0x02);
+	}
+
+	/* Screen A preset row scan: none */
+	vga_wcrt(cinfo->regbase, VGA_CRTC_PRESET_ROW, 0x00);
+	/* Text cursor start: disable text cursor */
+	vga_wcrt(cinfo->regbase, VGA_CRTC_CURSOR_START, 0x20);
+	/* Text cursor end: - */
+	vga_wcrt(cinfo->regbase, VGA_CRTC_CURSOR_END, 0x00);
+	/* text cursor location high: 0 */
+	vga_wcrt(cinfo->regbase, VGA_CRTC_CURSOR_HI, 0x00);
+	/* text cursor location low: 0 */
+	vga_wcrt(cinfo->regbase, VGA_CRTC_CURSOR_LO, 0x00);
+
+	/* Underline Row scanline: - */
+	vga_wcrt(cinfo->regbase, VGA_CRTC_UNDERLINE, 0x00);
+	/* ### add 0x40 for text modes with > 30 MHz pixclock */
+	/* ext. display controls: ext.adr. wrap */
+	vga_wcrt(cinfo->regbase, CL_CRT1B, 0x02);
+
+	/* Set/Reset registers: - */
+	vga_wgfx(cinfo->regbase, VGA_GFX_SR_VALUE, 0x00);
+	/* Set/Reset enable: - */
+	vga_wgfx(cinfo->regbase, VGA_GFX_SR_ENABLE, 0x00);
+	/* Color Compare: - */
+	vga_wgfx(cinfo->regbase, VGA_GFX_COMPARE_VALUE, 0x00);
+	/* Data Rotate: - */
+	vga_wgfx(cinfo->regbase, VGA_GFX_DATA_ROTATE, 0x00);
+	/* Read Map Select: - */
+	vga_wgfx(cinfo->regbase, VGA_GFX_PLANE_READ, 0x00);
+	/* Mode: conf. for 16/4/2 color mode, no odd/even, read/write mode 0 */
+	vga_wgfx(cinfo->regbase, VGA_GFX_MODE, 0x00);
+	/* Miscellaneous: memory map base address, graphics mode */
+	vga_wgfx(cinfo->regbase, VGA_GFX_MISC, 0x01);
+	/* Color Don't care: involve all planes */
+	vga_wgfx(cinfo->regbase, VGA_GFX_COMPARE_MASK, 0x0f);
+	/* Bit Mask: no mask at all */
+	vga_wgfx(cinfo->regbase, VGA_GFX_BIT_MASK, 0xff);
+
+	if (cinfo->btype == BT_ALPINE || cinfo->btype == BT_SD64 ||
+	    is_laguna(cinfo))
+		/* (5434 can't have bit 3 set for bitblt) */
+		vga_wgfx(cinfo->regbase, CL_GRB, 0x20);
+	else
+	/* Graphics controller mode extensions: finer granularity,
+	 * 8byte data latches
+	 */
+		vga_wgfx(cinfo->regbase, CL_GRB, 0x28);
+
+	vga_wgfx(cinfo->regbase, CL_GRC, 0xff);	/* Color Key compare: - */
+	vga_wgfx(cinfo->regbase, CL_GRD, 0x00);	/* Color Key compare mask: - */
+	vga_wgfx(cinfo->regbase, CL_GRE, 0x00);	/* Miscellaneous control: - */
+	/* Background color byte 1: - */
+	/*  vga_wgfx (cinfo->regbase, CL_GR10, 0x00); */
+	/*  vga_wgfx (cinfo->regbase, CL_GR11, 0x00); */
+
+	/* Attribute Controller palette registers: "identity mapping" */
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE0, 0x00);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE1, 0x01);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE2, 0x02);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE3, 0x03);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE4, 0x04);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE5, 0x05);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE6, 0x06);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE7, 0x07);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE8, 0x08);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTE9, 0x09);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTEA, 0x0a);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTEB, 0x0b);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTEC, 0x0c);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTED, 0x0d);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTEE, 0x0e);
+	vga_wattr(cinfo->regbase, VGA_ATC_PALETTEF, 0x0f);
+
+	/* Attribute Controller mode: graphics mode */
+	vga_wattr(cinfo->regbase, VGA_ATC_MODE, 0x01);
+	/* Overscan color reg.: reg. 0 */
+	vga_wattr(cinfo->regbase, VGA_ATC_OVERSCAN, 0x00);
+	/* Color Plane enable: Enable all 4 planes */
+	vga_wattr(cinfo->regbase, VGA_ATC_PLANE_ENABLE, 0x0f);
+	/* Color Select: - */
+	vga_wattr(cinfo->regbase, VGA_ATC_COLOR_PAGE, 0x00);
+
+	WGen(cinfo, VGA_PEL_MSK, 0xff);	/* Pixel mask: no mask */
+
+	/* BLT Start/status: Blitter reset */
+	vga_wgfx(cinfo->regbase, CL_GR31, 0x04);
+	/* - " -	   : "end-of-reset" */
+	vga_wgfx(cinfo->regbase, CL_GR31, 0x00);
+
+	/* misc... */
+	WHDR(cinfo, 0);	/* Hidden DAC register: - */
+	return;
+}
+
+static void switch_monitor(struct cirrusfb_info *cinfo, int on)
+{
+#ifdef CONFIG_ZORRO /* only works on Zorro boards */
+	static int IsOn = 0;	/* XXX not ok for multiple boards */
+
+	if (cinfo->btype == BT_PICASSO4)
+		return;		/* nothing to switch */
+	if (cinfo->btype == BT_ALPINE)
+		return;		/* nothing to switch */
+	if (cinfo->btype == BT_GD5480)
+		return;		/* nothing to switch */
+	if (cinfo->btype == BT_PICASSO) {
+		if ((on && !IsOn) || (!on && IsOn))
+			WSFR(cinfo, 0xff);
+		return;
+	}
+	if (on) {
+		switch (cinfo->btype) {
+		case BT_SD64:
+			WSFR(cinfo, cinfo->SFR | 0x21);
+			break;
+		case BT_PICCOLO:
+			WSFR(cinfo, cinfo->SFR | 0x28);
+			break;
+		case BT_SPECTRUM:
+			WSFR(cinfo, 0x6f);
+			break;
+		default: /* do nothing */ break;
+		}
+	} else {
+		switch (cinfo->btype) {
+		case BT_SD64:
+			WSFR(cinfo, cinfo->SFR & 0xde);
+			break;
+		case BT_PICCOLO:
+			WSFR(cinfo, cinfo->SFR & 0xd7);
+			break;
+		case BT_SPECTRUM:
+			WSFR(cinfo, 0x4f);
+			break;
+		default: /* do nothing */
+			break;
+		}
+	}
+#endif /* CONFIG_ZORRO */
+}
+
+/******************************************/
+/* Linux 2.6-style  accelerated functions */
+/******************************************/
+
+static int cirrusfb_sync(struct fb_info *info)
+{
+	struct cirrusfb_info *cinfo = info->par;
+
+	if (!is_laguna(cinfo)) {
+		while (vga_rgfx(cinfo->regbase, CL_GR31) & 0x03)
+			cpu_relax();
+	}
+	return 0;
+}
+
+static void cirrusfb_fillrect(struct fb_info *info,
+			      const struct fb_fillrect *region)
+{
+	struct fb_fillrect modded;
+	int vxres, vyres;
+	struct cirrusfb_info *cinfo = info->par;
+	int m = info->var.bits_per_pixel;
+	u32 color = (info->fix.visual == FB_VISUAL_TRUECOLOR) ?
+		cinfo->pseudo_palette[region->color] : region->color;
+
+	if (info->state != FBINFO_STATE_RUNNING)
+		return;
+	if (info->flags & FBINFO_HWACCEL_DISABLED) {
+		cfb_fillrect(info, region);
+		return;
+	}
+
+	vxres = info->var.xres_virtual;
+	vyres = info->var.yres_virtual;
+
+	memcpy(&modded, region, sizeof(struct fb_fillrect));
+
+	if (!modded.width || !modded.height ||
+	   modded.dx >= vxres || modded.dy >= vyres)
+		return;
+
+	if (modded.dx + modded.width  > vxres)
+		modded.width  = vxres - modded.dx;
+	if (modded.dy + modded.height > vyres)
+		modded.height = vyres - modded.dy;
+
+	cirrusfb_RectFill(cinfo->regbase,
+			  info->var.bits_per_pixel,
+			  (region->dx * m) / 8, region->dy,
+			  (region->width * m) / 8, region->height,
+			  color, color,
+			  info->fix.line_length, 0x40);
+}
+
+static void cirrusfb_copyarea(struct fb_info *info,
+			      const struct fb_copyarea *area)
+{
+	struct fb_copyarea modded;
+	u32 vxres, vyres;
+	struct cirrusfb_info *cinfo = info->par;
+	int m = info->var.bits_per_pixel;
+
+	if (info->state != FBINFO_STATE_RUNNING)
+		return;
+	if (info->flags & FBINFO_HWACCEL_DISABLED) {
+		cfb_copyarea(info, area);
+		return;
+	}
+
+	vxres = info->var.xres_virtual;
+	vyres = info->var.yres_virtual;
+	memcpy(&modded, area, sizeof(struct fb_copyarea));
+
+	if (!modded.width || !modded.height ||
+	   modded.sx >= vxres || modded.sy >= vyres ||
+	   modded.dx >= vxres || modded.dy >= vyres)
+		return;
+
+	if (modded.sx + modded.width > vxres)
+		modded.width = vxres - modded.sx;
+	if (modded.dx + modded.width > vxres)
+		modded.width = vxres - modded.dx;
+	if (modded.sy + modded.height > vyres)
+		modded.height = vyres - modded.sy;
+	if (modded.dy + modded.height > vyres)
+		modded.height = vyres - modded.dy;
+
+	cirrusfb_BitBLT(cinfo->regbase, info->var.bits_per_pixel,
+			(area->sx * m) / 8, area->sy,
+			(area->dx * m) / 8, area->dy,
+			(area->width * m) / 8, area->height,
+			info->fix.line_length);
+
+}
+
+static void cirrusfb_imageblit(struct fb_info *info,
+			       const struct fb_image *image)
+{
+	struct cirrusfb_info *cinfo = info->par;
+	unsigned char op = (info->var.bits_per_pixel == 24) ? 0xc : 0x4;
+
+	if (info->state != FBINFO_STATE_RUNNING)
+		return;
+	/* Alpine/SD64 does not work at 24bpp ??? */
+	if (info->flags & FBINFO_HWACCEL_DISABLED || image->depth != 1)
+		cfb_imageblit(info, image);
+	else if ((cinfo->btype == BT_ALPINE || cinfo->btype == BT_SD64) &&
+		  op == 0xc)
+		cfb_imageblit(info, image);
+	else {
+		unsigned size = ((image->width + 7) >> 3) * image->height;
+		int m = info->var.bits_per_pixel;
+		u32 fg, bg;
+
+		if (info->var.bits_per_pixel == 8) {
+			fg = image->fg_color;
+			bg = image->bg_color;
+		} else {
+			fg = ((u32 *)(info->pseudo_palette))[image->fg_color];
+			bg = ((u32 *)(info->pseudo_palette))[image->bg_color];
+		}
+		if (info->var.bits_per_pixel == 24) {
+			/* clear background first */
+			cirrusfb_RectFill(cinfo->regbase,
+					  info->var.bits_per_pixel,
+					  (image->dx * m) / 8, image->dy,
+					  (image->width * m) / 8,
+					  image->height,
+					  bg, bg,
+					  info->fix.line_length, 0x40);
+		}
+		cirrusfb_RectFill(cinfo->regbase,
+				  info->var.bits_per_pixel,
+				  (image->dx * m) / 8, image->dy,
+				  (image->width * m) / 8, image->height,
+				  fg, bg,
+				  info->fix.line_length, op);
+		memcpy(info->screen_base, image->data, size);
+	}
+}
+
+#ifdef CONFIG_PCI
+static int release_io_ports;
+
+/* Pulled the logic from XFree86 Cirrus driver to get the memory size,
+ * based on the DRAM bandwidth bit and DRAM bank switching bit.  This
+ * works with 1MB, 2MB and 4MB configurations (which the Motorola boards
+ * seem to have. */
+static unsigned int cirrusfb_get_memsize(struct fb_info *info,
+					 u8 __iomem *regbase)
+{
+	unsigned long mem;
+	struct cirrusfb_info *cinfo = info->par;
+
+	if (is_laguna(cinfo)) {
+		unsigned char SR14 = vga_rseq(regbase, CL_SEQR14);
+
+		mem = ((SR14 & 7) + 1) << 20;
+	} else {
+		unsigned char SRF = vga_rseq(regbase, CL_SEQRF);
+		switch ((SRF & 0x18)) {
+		case 0x08:
+			mem = 512 * 1024;
+			break;
+		case 0x10:
+			mem = 1024 * 1024;
+			break;
+		/* 64-bit DRAM data bus width; assume 2MB.
+		 * Also indicates 2MB memory on the 5430.
+		 */
+		case 0x18:
+			mem = 2048 * 1024;
+			break;
+		default:
+			dev_warn(info->device, "Unknown memory size!\n");
+			mem = 1024 * 1024;
+		}
+		/* If DRAM bank switching is enabled, there must be
+		 * twice as much memory installed. (4MB on the 5434)
+		 */
+		if (cinfo->btype != BT_ALPINE && (SRF & 0x80) != 0)
+			mem *= 2;
+	}
+
+	/* TODO: Handling of GD5446/5480 (see XF86 sources ...) */
+	return mem;
+}
+
+static void get_pci_addrs(const struct pci_dev *pdev,
+			  unsigned long *display, unsigned long *registers)
+{
+	assert(pdev != NULL);
+	assert(display != NULL);
+	assert(registers != NULL);
+
+	*display = 0;
+	*registers = 0;
+
+	/* This is a best-guess for now */
+
+	if (pci_resource_flags(pdev, 0) & IORESOURCE_IO) {
+		*display = pci_resource_start(pdev, 1);
+		*registers = pci_resource_start(pdev, 0);
+	} else {
+		*display = pci_resource_start(pdev, 0);
+		*registers = pci_resource_start(pdev, 1);
+	}
+
+	assert(*display != 0);
+}
+
+static void cirrusfb_pci_unmap(struct fb_info *info)
+{
+	struct pci_dev *pdev = to_pci_dev(info->device);
+	struct cirrusfb_info *cinfo = info->par;
+
+	if (cinfo->laguna_mmio == NULL)
+		iounmap(cinfo->laguna_mmio);
+	iounmap(info->screen_base);
+#if 0 /* if system didn't claim this region, we would... */
+	release_mem_region(0xA0000, 65535);
+#endif
+	if (release_io_ports)
+		release_region(0x3C0, 32);
+	pci_release_regions(pdev);
+}
+#endif /* CONFIG_PCI */
+
+#ifdef CONFIG_ZORRO
+static void cirrusfb_zorro_unmap(struct fb_info *info)
+{
+	struct cirrusfb_info *cinfo = info->par;
+	struct zorro_dev *zdev = to_zorro_dev(info->device);
+
+	if (info->fix.smem_start > 16 * MB_)
+		iounmap(info->screen_base);
+	if (info->fix.mmio_start > 16 * MB_)
+		iounmap(cinfo->regbase);
+
+	zorro_release_device(zdev);
+}
+#endif /* CONFIG_ZORRO */
+
+/* function table of the above functions */
+static const struct fb_ops cirrusfb_ops = {
+	.owner		= THIS_MODULE,
+	.fb_open	= cirrusfb_open,
+	.fb_release	= cirrusfb_release,
+	__FB_DEFAULT_IOMEM_OPS_RDWR,
+	.fb_setcolreg	= cirrusfb_setcolreg,
+	.fb_check_var	= cirrusfb_check_var,
+	.fb_set_par	= cirrusfb_set_par,
+	.fb_pan_display = cirrusfb_pan_display,
+	.fb_blank	= cirrusfb_blank,
+	.fb_fillrect	= cirrusfb_fillrect,
+	.fb_copyarea	= cirrusfb_copyarea,
+	.fb_sync	= cirrusfb_sync,
+	.fb_imageblit	= cirrusfb_imageblit,
+	__FB_DEFAULT_IOMEM_OPS_MMAP,
+};
+
+static int cirrusfb_set_fbinfo(struct fb_info *info)
+{
+	struct cirrusfb_info *cinfo = info->par;
+	struct fb_var_screeninfo *var = &info->var;
+
+	info->pseudo_palette = cinfo->pseudo_palette;
+	info->flags = FBINFO_HWACCEL_XPAN
+		    | FBINFO_HWACCEL_YPAN
+		    | FBINFO_HWACCEL_FILLRECT
+		    | FBINFO_HWACCEL_IMAGEBLIT
+		    | FBINFO_HWACCEL_COPYAREA;
+	if (noaccel || is_laguna(cinfo)) {
+		info->flags |= FBINFO_HWACCEL_DISABLED;
+		info->fix.accel = FB_ACCEL_NONE;
+	} else
+		info->fix.accel = FB_ACCEL_CIRRUS_ALPINE;
+
+	info->fbops = &cirrusfb_ops;
+
+	if (cinfo->btype == BT_GD5480) {
+		if (var->bits_per_pixel == 16)
+			info->screen_base += 1 * MB_;
+		if (var->bits_per_pixel == 32)
+			info->screen_base += 2 * MB_;
+	}
+
+	/* Fill fix common fields */
+	strscpy(info->fix.id, cirrusfb_board_info[cinfo->btype].name,
+		sizeof(info->fix.id));
+
+	/* monochrome: only 1 memory plane */
+	/* 8 bit and above: Use whole memory area */
+	info->fix.smem_len   = info->screen_size;
+	if (var->bits_per_pixel == 1)
+		info->fix.smem_len /= 4;
+	info->fix.type_aux   = 0;
+	info->fix.xpanstep   = 1;
+	info->fix.ypanstep   = 1;
+	info->fix.ywrapstep  = 0;
+
+	/* FIXME: map region at 0xB8000 if available, fill in here */
+	info->fix.mmio_len   = 0;
+
+	fb_alloc_cmap(&info->cmap, 256, 0);
+
+	return 0;
+}
+
+static int cirrusfb_register(struct fb_info *info)
+{
+	struct cirrusfb_info *cinfo = info->par;
+	int err;
+
+	/* sanity checks */
+	assert(cinfo->btype != BT_NONE);
+
+	/* set all the vital stuff */
+	cirrusfb_set_fbinfo(info);
+
+	dev_dbg(info->device, "(RAM start set to: 0x%p)\n", info->screen_base);
+
+	err = fb_find_mode(&info->var, info, mode_option, NULL, 0, NULL, 8);
+	if (!err) {
+		dev_dbg(info->device, "wrong initial video mode\n");
+		err = -EINVAL;
+		goto err_dealloc_cmap;
+	}
+
+	info->var.activate = FB_ACTIVATE_NOW;
+
+	err = cirrusfb_check_var(&info->var, info);
+	if (err < 0) {
+		/* should never happen */
+		dev_dbg(info->device,
+			"choking on default var... umm, no good.\n");
+		goto err_dealloc_cmap;
+	}
+
+	err = register_framebuffer(info);
+	if (err < 0) {
+		dev_err(info->device,
+			"could not register fb device; err = %d!\n", err);
+		goto err_dealloc_cmap;
+	}
+
+	return 0;
+
+err_dealloc_cmap:
+	fb_dealloc_cmap(&info->cmap);
+	return err;
+}
+
+static void cirrusfb_cleanup(struct fb_info *info)
+{
+	struct cirrusfb_info *cinfo = info->par;
+
+	switch_monitor(cinfo, 0);
+	unregister_framebuffer(info);
+	fb_dealloc_cmap(&info->cmap);
+	dev_dbg(info->device, "Framebuffer unregistered\n");
+	cinfo->unmap(info);
+	framebuffer_release(info);
+}
+
+#ifdef CONFIG_PCI
+static int cirrusfb_pci_register(struct pci_dev *pdev,
+				 const struct pci_device_id *ent)
+{
+	struct cirrusfb_info *cinfo;
+	struct fb_info *info;
+	unsigned long board_addr, board_size;
+	int ret;
+
+	ret = aperture_remove_conflicting_pci_devices(pdev, "cirrusfb");
+	if (ret)
+		return ret;
+
+	ret = pci_enable_device(pdev);
+	if (ret < 0) {
+		printk(KERN_ERR "cirrusfb: Cannot enable PCI device\n");
+		goto err_out;
+	}
+
+	info = framebuffer_alloc(sizeof(struct cirrusfb_info), &pdev->dev);
+	if (!info) {
+		ret = -ENOMEM;
+		goto err_out;
+	}
+
+	cinfo = info->par;
+	cinfo->btype = (enum cirrus_board) ent->driver_data;
+
+	dev_dbg(info->device,
+		" Found PCI device, base address 0 is 0x%Lx, btype set to %d\n",
+		(unsigned long long)pdev->resource[0].start,  cinfo->btype);
+	dev_dbg(info->device, " base address 1 is 0x%Lx\n",
+		(unsigned long long)pdev->resource[1].start);
+
+	dev_dbg(info->device,
+		"Attempt to get PCI info for Cirrus Graphics Card\n");
+	get_pci_addrs(pdev, &board_addr, &info->fix.mmio_start);
+	/* FIXME: this forces VGA.  alternatives? */
+	cinfo->regbase = NULL;
+	cinfo->laguna_mmio = ioremap(info->fix.mmio_start, 0x1000);
+
+	dev_dbg(info->device, "Board address: 0x%lx, register address: 0x%lx\n",
+		board_addr, info->fix.mmio_start);
+
+	board_size = (cinfo->btype == BT_GD5480) ?
+		32 * MB_ : cirrusfb_get_memsize(info, cinfo->regbase);
+
+	ret = pci_request_regions(pdev, "cirrusfb");
+	if (ret < 0) {
+		dev_err(info->device, "cannot reserve region 0x%lx, abort\n",
+			board_addr);
+		goto err_release_fb;
+	}
+#if 0 /* if the system didn't claim this region, we would... */
+	if (!request_mem_region(0xA0000, 65535, "cirrusfb")) {
+		dev_err(info->device, "cannot reserve region 0x%lx, abort\n",
+			0xA0000L);
+		ret = -EBUSY;
+		goto err_release_regions;
+	}
+#endif
+	if (request_region(0x3C0, 32, "cirrusfb"))
+		release_io_ports = 1;
+
+	info->screen_base = ioremap(board_addr, board_size);
+	if (!info->screen_base) {
+		ret = -EIO;
+		goto err_release_legacy;
+	}
+
+	info->fix.smem_start = board_addr;
+	info->screen_size = board_size;
+	cinfo->unmap = cirrusfb_pci_unmap;
+
+	dev_info(info->device,
+		 "Cirrus Logic chipset on PCI bus, RAM (%lu kB) at 0x%lx\n",
+		 info->screen_size >> 10, board_addr);
+	pci_set_drvdata(pdev, info);
+
+	ret = cirrusfb_register(info);
+	if (!ret)
+		return 0;
+
+	iounmap(info->screen_base);
+err_release_legacy:
+	if (release_io_ports)
+		release_region(0x3C0, 32);
+#if 0
+	release_mem_region(0xA0000, 65535);
+err_release_regions:
+#endif
+	pci_release_regions(pdev);
+err_release_fb:
+	if (cinfo->laguna_mmio != NULL)
+		iounmap(cinfo->laguna_mmio);
+	framebuffer_release(info);
+err_out:
+	return ret;
+}
+
+static void cirrusfb_pci_unregister(struct pci_dev *pdev)
+{
+	struct fb_info *info = pci_get_drvdata(pdev);
+
+	cirrusfb_cleanup(info);
+}
+
+static struct pci_driver cirrusfb_pci_driver = {
+	.name		= "cirrusfb",
+	.id_table	= cirrusfb_pci_table,
+	.probe		= cirrusfb_pci_register,
+	.remove		= cirrusfb_pci_unregister,
+};
+#endif /* CONFIG_PCI */
+
+#ifdef CONFIG_ZORRO
+static int cirrusfb_zorro_register(struct zorro_dev *z,
+				   const struct zorro_device_id *ent)
+{
+	struct fb_info *info;
+	int error;
+	const struct zorrocl *zcl;
+	enum cirrus_board btype;
+	unsigned long regbase, ramsize, rambase;
+	struct cirrusfb_info *cinfo;
+
+	info = framebuffer_alloc(sizeof(struct cirrusfb_info), &z->dev);
+	if (!info)
+		return -ENOMEM;
+
+	zcl = (const struct zorrocl *)ent->driver_data;
+	btype = zcl->type;
+	regbase = zorro_resource_start(z) + zcl->regoffset;
+	ramsize = zcl->ramsize;
+	if (ramsize) {
+		rambase = zorro_resource_start(z) + zcl->ramoffset;
+		if (zorro_resource_len(z) == 64 * MB_) {
+			/* Quirk for 64 MiB Picasso IV */
+			rambase += zcl->ramoffset;
+		}
+	} else {
+		struct zorro_dev *ram = zorro_find_device(zcl->ramid, NULL);
+		if (!ram || !zorro_resource_len(ram)) {
+			dev_err(info->device, "No video RAM found\n");
+			error = -ENODEV;
+			goto err_release_fb;
+		}
+		rambase = zorro_resource_start(ram);
+		ramsize = zorro_resource_len(ram);
+		if (zcl->ramid2 &&
+		    (ram = zorro_find_device(zcl->ramid2, NULL))) {
+			if (zorro_resource_start(ram) != rambase + ramsize) {
+				dev_warn(info->device,
+					 "Skipping non-contiguous RAM at %pR\n",
+					 &ram->resource);
+			} else {
+				ramsize += zorro_resource_len(ram);
+			}
+		}
+	}
+
+	dev_info(info->device,
+		 "%s board detected, REG at 0x%lx, %lu MiB RAM at 0x%lx\n",
+		 cirrusfb_board_info[btype].name, regbase, ramsize / MB_,
+		 rambase);
+
+	if (!zorro_request_device(z, "cirrusfb")) {
+		dev_err(info->device, "Cannot reserve %pR\n", &z->resource);
+		error = -EBUSY;
+		goto err_release_fb;
+	}
+
+	cinfo = info->par;
+	cinfo->btype = btype;
+
+	info->fix.mmio_start = regbase;
+	cinfo->regbase = regbase > 16 * MB_ ? ioremap(regbase, 64 * 1024)
+					    : ZTWO_VADDR(regbase);
+	if (!cinfo->regbase) {
+		dev_err(info->device, "Cannot map registers\n");
+		error = -EIO;
+		goto err_release_dev;
+	}
+
+	info->fix.smem_start = rambase;
+	info->screen_size = ramsize;
+	info->screen_base = rambase > 16 * MB_ ? ioremap(rambase, ramsize)
+					       : ZTWO_VADDR(rambase);
+	if (!info->screen_base) {
+		dev_err(info->device, "Cannot map video RAM\n");
+		error = -EIO;
+		goto err_unmap_reg;
+	}
+
+	cinfo->unmap = cirrusfb_zorro_unmap;
+
+	dev_info(info->device,
+		 "Cirrus Logic chipset on Zorro bus, RAM (%lu MiB) at 0x%lx\n",
+		 ramsize / MB_, rambase);
+
+	/* MCLK select etc. */
+	if (cirrusfb_board_info[btype].init_sr1f)
+		vga_wseq(cinfo->regbase, CL_SEQR1F,
+			 cirrusfb_board_info[btype].sr1f);
+
+	error = cirrusfb_register(info);
+	if (error) {
+		dev_err(info->device, "Failed to register device, error %d\n",
+			error);
+		goto err_unmap_ram;
+	}
+
+	zorro_set_drvdata(z, info);
+	return 0;
+
+err_unmap_ram:
+	if (rambase > 16 * MB_)
+		iounmap(info->screen_base);
+
+err_unmap_reg:
+	if (regbase > 16 * MB_)
+		iounmap(cinfo->regbase);
+err_release_dev:
+	zorro_release_device(z);
+err_release_fb:
+	framebuffer_release(info);
+	return error;
+}
+
+static void cirrusfb_zorro_unregister(struct zorro_dev *z)
+{
+	struct fb_info *info = zorro_get_drvdata(z);
+
+	cirrusfb_cleanup(info);
+	zorro_set_drvdata(z, NULL);
+}
+
+static struct zorro_driver cirrusfb_zorro_driver = {
+	.name		= "cirrusfb",
+	.id_table	= cirrusfb_zorro_table,
+	.probe		= cirrusfb_zorro_register,
+	.remove		= cirrusfb_zorro_unregister,
+};
+#endif /* CONFIG_ZORRO */
+
+#ifndef MODULE
+static int __init cirrusfb_setup(char *options)
+{
+	char *this_opt;
+
+	if (!options || !*options)
+		return 0;
+
+	while ((this_opt = strsep(&options, ",")) != NULL) {
+		if (!*this_opt)
+			continue;
+
+		if (!strcmp(this_opt, "noaccel"))
+			noaccel = 1;
+		else if (!strncmp(this_opt, "mode:", 5))
+			mode_option = this_opt + 5;
+		else
+			mode_option = this_opt;
+	}
+	return 0;
+}
+#endif
+
+    /*
+     *  Modularization
+     */
+
+MODULE_AUTHOR("Copyright 1999,2000 Jeff Garzik <jgarzik@pobox.com>");
+MODULE_DESCRIPTION("Accelerated FBDev driver for Cirrus Logic chips");
+MODULE_LICENSE("GPL");
+
+static int __init cirrusfb_init(void)
+{
+	int error = 0;
+
+#ifndef MODULE
+	char *option = NULL;
+#endif
+
+	if (fb_modesetting_disabled("cirrusfb"))
+		return -ENODEV;
+
+#ifndef MODULE
+	if (fb_get_options("cirrusfb", &option))
+		return -ENODEV;
+	cirrusfb_setup(option);
+#endif
+
+#ifdef CONFIG_ZORRO
+	error |= zorro_register_driver(&cirrusfb_zorro_driver);
+#endif
+#ifdef CONFIG_PCI
+	error |= pci_register_driver(&cirrusfb_pci_driver);
+#endif
+	return error;
+}
+
+static void __exit cirrusfb_exit(void)
+{
+#ifdef CONFIG_PCI
+	pci_unregister_driver(&cirrusfb_pci_driver);
+#endif
+#ifdef CONFIG_ZORRO
+	zorro_unregister_driver(&cirrusfb_zorro_driver);
+#endif
+}
+
+module_init(cirrusfb_init);
+
+module_param(mode_option, charp, 0);
+MODULE_PARM_DESC(mode_option, "Initial video mode e.g. '648x480-8@60'");
+module_param(noaccel, bool, 0);
+MODULE_PARM_DESC(noaccel, "Disable acceleration");
+
+#ifdef MODULE
+module_exit(cirrusfb_exit);
+#endif
+
+/**********************************************************************/
+/* about the following functions - I have used the same names for the */
+/* functions as Markus Wild did in his Retina driver for NetBSD as    */
+/* they just made sense for this purpose. Apart from that, I wrote    */
+/* these functions myself.					    */
+/**********************************************************************/
+
+/*** WGen() - write into one of the external/general registers ***/
+static void WGen(const struct cirrusfb_info *cinfo,
+		  int regnum, unsigned char val)
+{
+	unsigned long regofs = 0;
+
+	if (cinfo->btype == BT_PICASSO) {
+		/* Picasso II specific hack */
+/*	      if (regnum == VGA_PEL_IR || regnum == VGA_PEL_D ||
+		  regnum == CL_VSSM2) */
+		if (regnum == VGA_PEL_IR || regnum == VGA_PEL_D)
+			regofs = 0xfff;
+	}
+
+	vga_w(cinfo->regbase, regofs + regnum, val);
+}
+
+/*** RGen() - read out one of the external/general registers ***/
+static unsigned char RGen(const struct cirrusfb_info *cinfo, int regnum)
+{
+	unsigned long regofs = 0;
+
+	if (cinfo->btype == BT_PICASSO) {
+		/* Picasso II specific hack */
+/*	      if (regnum == VGA_PEL_IR || regnum == VGA_PEL_D ||
+		  regnum == CL_VSSM2) */
+		if (regnum == VGA_PEL_IR || regnum == VGA_PEL_D)
+			regofs = 0xfff;
+	}
+
+	return vga_r(cinfo->regbase, regofs + regnum);
+}
+
+/*** AttrOn() - turn on VideoEnable for Attribute controller ***/
+static void AttrOn(const struct cirrusfb_info *cinfo)
+{
+	assert(cinfo != NULL);
+
+	if (vga_rcrt(cinfo->regbase, CL_CRT24) & 0x80) {
+		/* if we're just in "write value" mode, write back the */
+		/* same value as before to not modify anything */
+		vga_w(cinfo->regbase, VGA_ATT_IW,
+		      vga_r(cinfo->regbase, VGA_ATT_R));
+	}
+	/* turn on video bit */
+/*      vga_w(cinfo->regbase, VGA_ATT_IW, 0x20); */
+	vga_w(cinfo->regbase, VGA_ATT_IW, 0x33);
+
+	/* dummy write on Reg0 to be on "write index" mode next time */
+	vga_w(cinfo->regbase, VGA_ATT_IW, 0x00);
+}
+
+/*** WHDR() - write into the Hidden DAC register ***/
+/* as the HDR is the only extension register that requires special treatment
+ * (the other extension registers are accessible just like the "ordinary"
+ * registers of their functional group) here is a specialized routine for
+ * accessing the HDR
+ */
+static void WHDR(const struct cirrusfb_info *cinfo, unsigned char val)
+{
+	if (is_laguna(cinfo))
+		return;
+	if (cinfo->btype == BT_PICASSO) {
+		/* Klaus' hint for correct access to HDR on some boards */
+		/* first write 0 to pixel mask (3c6) */
+		WGen(cinfo, VGA_PEL_MSK, 0x00);
+		udelay(200);
+		/* next read dummy from pixel address (3c8) */
+		RGen(cinfo, VGA_PEL_IW);
+		udelay(200);
+	}
+	/* now do the usual stuff to access the HDR */
+
+	RGen(cinfo, VGA_PEL_MSK);
+	udelay(200);
+	RGen(cinfo, VGA_PEL_MSK);
+	udelay(200);
+	RGen(cinfo, VGA_PEL_MSK);
+	udelay(200);
+	RGen(cinfo, VGA_PEL_MSK);
+	udelay(200);
+
+	WGen(cinfo, VGA_PEL_MSK, val);
+	udelay(200);
+
+	if (cinfo->btype == BT_PICASSO) {
+		/* now first reset HDR access counter */
+		RGen(cinfo, VGA_PEL_IW);
+		udelay(200);
+
+		/* and at the end, restore the mask value */
+		/* ## is this mask always 0xff? */
+		WGen(cinfo, VGA_PEL_MSK, 0xff);
+		udelay(200);
+	}
+}
+
+/*** WSFR() - write to the "special function register" (SFR) ***/
+static void WSFR(struct cirrusfb_info *cinfo, unsigned char val)
+{
+#ifdef CONFIG_ZORRO
+	assert(cinfo->regbase != NULL);
+	cinfo->SFR = val;
+	z_writeb(val, cinfo->regbase + 0x8000);
+#endif
+}
+
+/* The Picasso has a second register for switching the monitor bit */
+static void WSFR2(struct cirrusfb_info *cinfo, unsigned char val)
+{
+#ifdef CONFIG_ZORRO
+	/* writing an arbitrary value to this one causes the monitor switcher */
+	/* to flip to Amiga display */
+	assert(cinfo->regbase != NULL);
+	cinfo->SFR = val;
+	z_writeb(val, cinfo->regbase + 0x9000);
+#endif
+}
+
+/*** WClut - set CLUT entry (range: 0..63) ***/
+static void WClut(struct cirrusfb_info *cinfo, unsigned char regnum, unsigned char red,
+	    unsigned char green, unsigned char blue)
+{
+	unsigned int data = VGA_PEL_D;
+
+	/* address write mode register is not translated.. */
+	vga_w(cinfo->regbase, VGA_PEL_IW, regnum);
+
+	if (cinfo->btype == BT_PICASSO || cinfo->btype == BT_PICASSO4 ||
+	    cinfo->btype == BT_ALPINE || cinfo->btype == BT_GD5480 ||
+	    cinfo->btype == BT_SD64 || is_laguna(cinfo)) {
+		/* but DAC data register IS, at least for Picasso II */
+		if (cinfo->btype == BT_PICASSO)
+			data += 0xfff;
+		vga_w(cinfo->regbase, data, red);
+		vga_w(cinfo->regbase, data, green);
+		vga_w(cinfo->regbase, data, blue);
+	} else {
+		vga_w(cinfo->regbase, data, blue);
+		vga_w(cinfo->regbase, data, green);
+		vga_w(cinfo->regbase, data, red);
+	}
+}
+
+#if 0
+/*** RClut - read CLUT entry (range 0..63) ***/
+static void RClut(struct cirrusfb_info *cinfo, unsigned char regnum, unsigned char *red,
+	    unsigned char *green, unsigned char *blue)
+{
+	unsigned int data = VGA_PEL_D;
+
+	vga_w(cinfo->regbase, VGA_PEL_IR, regnum);
+
+	if (cinfo->btype == BT_PICASSO || cinfo->btype == BT_PICASSO4 ||
+	    cinfo->btype == BT_ALPINE || cinfo->btype == BT_GD5480) {
+		if (cinfo->btype == BT_PICASSO)
+			data += 0xfff;
+		*red = vga_r(cinfo->regbase, data);
+		*green = vga_r(cinfo->regbase, data);
+		*blue = vga_r(cinfo->regbase, data);
+	} else {
+		*blue = vga_r(cinfo->regbase, data);
+		*green = vga_r(cinfo->regbase, data);
+		*red = vga_r(cinfo->regbase, data);
+	}
+}
+#endif
+
+/*******************************************************************
+	cirrusfb_WaitBLT()
+
+	Wait for the BitBLT engine to complete a possible earlier job
+*********************************************************************/
+
+/* FIXME: use interrupts instead */
+static void cirrusfb_WaitBLT(u8 __iomem *regbase)
+{
+	while (vga_rgfx(regbase, CL_GR31) & 0x08)
+		cpu_relax();
+}
+
+/*******************************************************************
+	cirrusfb_BitBLT()
+
+	perform accelerated "scrolling"
+********************************************************************/
+
+static void cirrusfb_set_blitter(u8 __iomem *regbase,
+			    u_short nwidth, u_short nheight,
+			    u_long nsrc, u_long ndest,
+			    u_short bltmode, u_short line_length)
+
+{
+	/* pitch: set to line_length */
+	/* dest pitch low */
+	vga_wgfx(regbase, CL_GR24, line_length & 0xff);
+	/* dest pitch hi */
+	vga_wgfx(regbase, CL_GR25, line_length >> 8);
+	/* source pitch low */
+	vga_wgfx(regbase, CL_GR26, line_length & 0xff);
+	/* source pitch hi */
+	vga_wgfx(regbase, CL_GR27, line_length >> 8);
+
+	/* BLT width: actual number of pixels - 1 */
+	/* BLT width low */
+	vga_wgfx(regbase, CL_GR20, nwidth & 0xff);
+	/* BLT width hi */
+	vga_wgfx(regbase, CL_GR21, nwidth >> 8);
+
+	/* BLT height: actual number of lines -1 */
+	/* BLT height low */
+	vga_wgfx(regbase, CL_GR22, nheight & 0xff);
+	/* BLT width hi */
+	vga_wgfx(regbase, CL_GR23, nheight >> 8);
+
+	/* BLT destination */
+	/* BLT dest low */
+	vga_wgfx(regbase, CL_GR28, (u_char) (ndest & 0xff));
+	/* BLT dest mid */
+	vga_wgfx(regbase, CL_GR29, (u_char) (ndest >> 8));
+	/* BLT dest hi */
+	vga_wgfx(regbase, CL_GR2A, (u_char) (ndest >> 16));
+
+	/* BLT source */
+	/* BLT src low */
+	vga_wgfx(regbase, CL_GR2C, (u_char) (nsrc & 0xff));
+	/* BLT src mid */
+	vga_wgfx(regbase, CL_GR2D, (u_char) (nsrc >> 8));
+	/* BLT src hi */
+	vga_wgfx(regbase, CL_GR2E, (u_char) (nsrc >> 16));
+
+	/* BLT mode */
+	vga_wgfx(regbase, CL_GR30, bltmode);	/* BLT mode */
+
+	/* BLT ROP: SrcCopy */
+	vga_wgfx(regbase, CL_GR32, 0x0d);	/* BLT ROP */
+
+	/* and finally: GO! */
+	vga_wgfx(regbase, CL_GR31, 0x02);	/* BLT Start/status */
+}
+
+/*******************************************************************
+	cirrusfb_BitBLT()
+
+	perform accelerated "scrolling"
+********************************************************************/
+
+static void cirrusfb_BitBLT(u8 __iomem *regbase, int bits_per_pixel,
+			    u_short curx, u_short cury,
+			    u_short destx, u_short desty,
+			    u_short width, u_short height,
+			    u_short line_length)
+{
+	u_short nwidth = width - 1;
+	u_short nheight = height - 1;
+	u_long nsrc, ndest;
+	u_char bltmode;
+
+	bltmode = 0x00;
+	/* if source adr < dest addr, do the Blt backwards */
+	if (cury <= desty) {
+		if (cury == desty) {
+			/* if src and dest are on the same line, check x */
+			if (curx < destx)
+				bltmode |= 0x01;
+		} else
+			bltmode |= 0x01;
+	}
+	/* standard case: forward blitting */
+	nsrc = (cury * line_length) + curx;
+	ndest = (desty * line_length) + destx;
+	if (bltmode) {
+		/* this means start addresses are at the end,
+		 * counting backwards
+		 */
+		nsrc += nheight * line_length + nwidth;
+		ndest += nheight * line_length + nwidth;
+	}
+
+	cirrusfb_WaitBLT(regbase);
+
+	cirrusfb_set_blitter(regbase, nwidth, nheight,
+			    nsrc, ndest, bltmode, line_length);
+}
+
+/*******************************************************************
+	cirrusfb_RectFill()
+
+	perform accelerated rectangle fill
+********************************************************************/
+
+static void cirrusfb_RectFill(u8 __iomem *regbase, int bits_per_pixel,
+		     u_short x, u_short y, u_short width, u_short height,
+		     u32 fg_color, u32 bg_color, u_short line_length,
+		     u_char blitmode)
+{
+	u_long ndest = (y * line_length) + x;
+	u_char op;
+
+	cirrusfb_WaitBLT(regbase);
+
+	/* This is a ColorExpand Blt, using the */
+	/* same color for foreground and background */
+	vga_wgfx(regbase, VGA_GFX_SR_VALUE, bg_color);
+	vga_wgfx(regbase, VGA_GFX_SR_ENABLE, fg_color);
+
+	op = 0x80;
+	if (bits_per_pixel >= 16) {
+		vga_wgfx(regbase, CL_GR10, bg_color >> 8);
+		vga_wgfx(regbase, CL_GR11, fg_color >> 8);
+		op = 0x90;
+	}
+	if (bits_per_pixel >= 24) {
+		vga_wgfx(regbase, CL_GR12, bg_color >> 16);
+		vga_wgfx(regbase, CL_GR13, fg_color >> 16);
+		op = 0xa0;
+	}
+	if (bits_per_pixel == 32) {
+		vga_wgfx(regbase, CL_GR14, bg_color >> 24);
+		vga_wgfx(regbase, CL_GR15, fg_color >> 24);
+		op = 0xb0;
+	}
+	cirrusfb_set_blitter(regbase, width - 1, height - 1,
+			    0, ndest, op | blitmode, line_length);
+}
+
+/**************************************************************************
+ * bestclock() - determine closest possible clock lower(?) than the
+ * desired pixel clock
+ **************************************************************************/
+static void bestclock(long freq, int *nom, int *den, int *div)
+{
+	int n, d;
+	long h, diff;
+
+	assert(nom != NULL);
+	assert(den != NULL);
+	assert(div != NULL);
+
+	*nom = 0;
+	*den = 0;
+	*div = 0;
+
+	if (freq < 8000)
+		freq = 8000;
+
+	diff = freq;
+
+	for (n = 32; n < 128; n++) {
+		int s = 0;
+
+		d = (14318 * n) / freq;
+		if ((d >= 7) && (d <= 63)) {
+			int temp = d;
+
+			if (temp > 31) {
+				s = 1;
+				temp >>= 1;
+			}
+			h = ((14318 * n) / temp) >> s;
+			h = h > freq ? h - freq : freq - h;
+			if (h < diff) {
+				diff = h;
+				*nom = n;
+				*den = temp;
+				*div = s;
+			}
+		}
+		d++;
+		if ((d >= 7) && (d <= 63)) {
+			if (d > 31) {
+				s = 1;
+				d >>= 1;
+			}
+			h = ((14318 * n) / d) >> s;
+			h = h > freq ? h - freq : freq - h;
+			if (h < diff) {
+				diff = h;
+				*nom = n;
+				*den = d;
+				*div = s;
+			}
+		}
+	}
+}
+
+/* -------------------------------------------------------------------------
+ *
+ * debugging functions
+ *
+ * -------------------------------------------------------------------------
+ */
+
+#ifdef CIRRUSFB_DEBUG
+
+/*
+ * cirrusfb_dbg_print_regs
+ * @regbase: If using newmmio, the newmmio base address, otherwise %NULL
+ * @reg_class: type of registers to read: %CRT, or %SEQ
+ *
+ * DESCRIPTION:
+ * Dumps the given list of VGA CRTC registers.  If @base is %NULL,
+ * old-style I/O ports are queried for information, otherwise MMIO is
+ * used at the given @base address to query the information.
+ */
+
+static void cirrusfb_dbg_print_regs(struct fb_info *info,
+				    caddr_t regbase,
+				    enum cirrusfb_dbg_reg_class reg_class, ...)
+{
+	va_list list;
+	unsigned char val = 0;
+	unsigned reg;
+	char *name;
+
+	va_start(list, reg_class);
+
+	name = va_arg(list, char *);
+	while (name != NULL) {
+		reg = va_arg(list, int);
+
+		switch (reg_class) {
+		case CRT:
+			val = vga_rcrt(regbase, (unsigned char) reg);
+			break;
+		case SEQ:
+			val = vga_rseq(regbase, (unsigned char) reg);
+			break;
+		default:
+			/* should never occur */
+			assert(false);
+			break;
+		}
+
+		dev_dbg(info->device, "%8s = 0x%02X\n", name, val);
+
+		name = va_arg(list, char *);
+	}
+
+	va_end(list);
+}
+
+/*
+ * cirrusfb_dbg_reg_dump
+ * @base: If using newmmio, the newmmio base address, otherwise %NULL
+ *
+ * DESCRIPTION:
+ * Dumps a list of interesting VGA and CIRRUSFB registers.  If @base is %NULL,
+ * old-style I/O ports are queried for information, otherwise MMIO is
+ * used at the given @base address to query the information.
+ */
+
+static void cirrusfb_dbg_reg_dump(struct fb_info *info, caddr_t regbase)
+{
+	dev_dbg(info->device, "VGA CRTC register dump:\n");
+
+	cirrusfb_dbg_print_regs(info, regbase, CRT,
+			   "CR00", 0x00,
+			   "CR01", 0x01,
+			   "CR02", 0x02,
+			   "CR03", 0x03,
+			   "CR04", 0x04,
+			   "CR05", 0x05,
+			   "CR06", 0x06,
+			   "CR07", 0x07,
+			   "CR08", 0x08,
+			   "CR09", 0x09,
+			   "CR0A", 0x0A,
+			   "CR0B", 0x0B,
+			   "CR0C", 0x0C,
+			   "CR0D", 0x0D,
+			   "CR0E", 0x0E,
+			   "CR0F", 0x0F,
+			   "CR10", 0x10,
+			   "CR11", 0x11,
+			   "CR12", 0x12,
+			   "CR13", 0x13,
+			   "CR14", 0x14,
+			   "CR15", 0x15,
+			   "CR16", 0x16,
+			   "CR17", 0x17,
+			   "CR18", 0x18,
+			   "CR22", 0x22,
+			   "CR24", 0x24,
+			   "CR26", 0x26,
+			   "CR2D", 0x2D,
+			   "CR2E", 0x2E,
+			   "CR2F", 0x2F,
+			   "CR30", 0x30,
+			   "CR31", 0x31,
+			   "CR32", 0x32,
+			   "CR33", 0x33,
+			   "CR34", 0x34,
+			   "CR35", 0x35,
+			   "CR36", 0x36,
+			   "CR37", 0x37,
+			   "CR38", 0x38,
+			   "CR39", 0x39,
+			   "CR3A", 0x3A,
+			   "CR3B", 0x3B,
+			   "CR3C", 0x3C,
+			   "CR3D", 0x3D,
+			   "CR3E", 0x3E,
+			   "CR3F", 0x3F,
+			   NULL);
+
+	dev_dbg(info->device, "\n");
+
+	dev_dbg(info->device, "VGA SEQ register dump:\n");
+
+	cirrusfb_dbg_print_regs(info, regbase, SEQ,
+			   "SR00", 0x00,
+			   "SR01", 0x01,
+			   "SR02", 0x02,
+			   "SR03", 0x03,
+			   "SR04", 0x04,
+			   "SR08", 0x08,
+			   "SR09", 0x09,
+			   "SR0A", 0x0A,
+			   "SR0B", 0x0B,
+			   "SR0D", 0x0D,
+			   "SR10", 0x10,
+			   "SR11", 0x11,
+			   "SR12", 0x12,
+			   "SR13", 0x13,
+			   "SR14", 0x14,
+			   "SR15", 0x15,
+			   "SR16", 0x16,
+			   "SR17", 0x17,
+			   "SR18", 0x18,
+			   "SR19", 0x19,
+			   "SR1A", 0x1A,
+			   "SR1B", 0x1B,
+			   "SR1C", 0x1C,
+			   "SR1D", 0x1D,
+			   "SR1E", 0x1E,
+			   "SR1F", 0x1F,
+			   NULL);
+
+	dev_dbg(info->device, "\n");
+}
+
+#endif				/* CIRRUSFB_DEBUG */
+
-- 
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