sched_ext: Maintain an online cid mask in the scheduler arenagrafted

Schedulers on the default cid mapping treat [0, nr_online_cids) as the
online set and restart on hotplug. Schedulers that install their own mapping
with scx_bpf_cid_override() have no way to learn which cids are online: the
count no longer identifies members and the CPU-form cpumask is unusable from
cid programs. This is an obvious hole in the cid API.

Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's
arena, allocated alongside the per-CPU scratch masks and populated after the
cid mapping is finalized and before ops.init(), for child schedulers too.
The pointer stays valid through ops.exit() with no reference to take. It is
the arena offset as a void pointer, the same form struct_ops arena arguments
arrive in. The verifier types the void return as a scalar for the program's
arena cast.

The mask follows the SCX hotplug notifications: seeded from cpu_active_mask
and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask
only inside a hotplug transition. Updates walk the scheduler list under the
lock that also serializes unlinking. Reads are live, not atomic snapshots.
Root initialization excludes hotplug.

v2: Reworded the getter kerneldoc (Andrea Righi).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

1 files changed, 477 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/wm9713.c b/drivers/input/touchscreen/wm9713.c
new file mode 100644
index 000000000..6f13f46ce
--- /dev/null
+++ b/drivers/input/touchscreen/wm9713.c
@@ -0,0 +1,477 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * wm9713.c  --  Codec touch driver for Wolfson WM9713 AC97 Codec.
+ *
+ * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
+ * Author: Liam Girdwood <lrg@slimlogic.co.uk>
+ * Parts Copyright : Ian Molton <spyro@f2s.com>
+ *                   Andrew Zabolotny <zap@homelink.ru>
+ *                   Russell King <rmk@arm.linux.org.uk>
+ */
+
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/input.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+#include <linux/wm97xx.h>
+
+#define TS_NAME			"wm97xx"
+#define WM9713_VERSION		"1.00"
+#define DEFAULT_PRESSURE	0xb0c0
+
+/*
+ * Module parameters
+ */
+
+/*
+ * Set internal pull up for pen detect.
+ *
+ * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
+ * i.e. pull up resistance = 64k Ohms / rpu.
+ *
+ * Adjust this value if you are having problems with pen detect not
+ * detecting any down event.
+ */
+static int rpu = 8;
+module_param(rpu, int, 0);
+MODULE_PARM_DESC(rpu, "Set internal pull up resistor for pen detect.");
+
+/*
+ * Set current used for pressure measurement.
+ *
+ * Set pil = 2 to use 400uA
+ *     pil = 1 to use 200uA and
+ *     pil = 0 to disable pressure measurement.
+ *
+ * This is used to increase the range of values returned by the adc
+ * when measureing touchpanel pressure.
+ */
+static int pil;
+module_param(pil, int, 0);
+MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
+
+/*
+ * Set threshold for pressure measurement.
+ *
+ * Pen down pressure below threshold is ignored.
+ */
+static int pressure = DEFAULT_PRESSURE & 0xfff;
+module_param(pressure, int, 0);
+MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
+
+/*
+ * Set adc sample delay.
+ *
+ * For accurate touchpanel measurements, some settling time may be
+ * required between the switch matrix applying a voltage across the
+ * touchpanel plate and the ADC sampling the signal.
+ *
+ * This delay can be set by setting delay = n, where n is the array
+ * position of the delay in the array delay_table below.
+ * Long delays > 1ms are supported for completeness, but are not
+ * recommended.
+ */
+static int delay = 4;
+module_param(delay, int, 0);
+MODULE_PARM_DESC(delay, "Set adc sample delay.");
+
+/*
+ * Set five_wire = 1 to use a 5 wire touchscreen.
+ *
+ * NOTE: Five wire mode does not allow for readback of pressure.
+ */
+static int five_wire;
+module_param(five_wire, int, 0);
+MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");
+
+/*
+ * Set adc mask function.
+ *
+ * Sources of glitch noise, such as signals driving an LCD display, may feed
+ * through to the touch screen plates and affect measurement accuracy. In
+ * order to minimise this, a signal may be applied to the MASK pin to delay or
+ * synchronise the sampling.
+ *
+ * 0 = No delay or sync
+ * 1 = High on pin stops conversions
+ * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
+ * 3 = Edge triggered, edge on pin starts conversion after delay param
+ */
+static int mask;
+module_param(mask, int, 0);
+MODULE_PARM_DESC(mask, "Set adc mask function.");
+
+/*
+ * Coordinate Polling Enable.
+ *
+ * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
+ * for every poll.
+ */
+static int coord;
+module_param(coord, int, 0);
+MODULE_PARM_DESC(coord, "Polling coordinate mode");
+
+/*
+ * ADC sample delay times in uS
+ */
+static const int delay_table[] = {
+	21,    /* 1 AC97 Link frames */
+	42,    /* 2 */
+	84,    /* 4 */
+	167,   /* 8 */
+	333,   /* 16 */
+	667,   /* 32 */
+	1000,  /* 48 */
+	1333,  /* 64 */
+	2000,  /* 96 */
+	2667,  /* 128 */
+	3333,  /* 160 */
+	4000,  /* 192 */
+	4667,  /* 224 */
+	5333,  /* 256 */
+	6000,  /* 288 */
+	0      /* No delay, switch matrix always on */
+};
+
+/*
+ * Delay after issuing a POLL command.
+ *
+ * The delay is 3 AC97 link frames + the touchpanel settling delay
+ */
+static inline void poll_delay(int d)
+{
+	udelay(3 * AC97_LINK_FRAME + delay_table[d]);
+}
+
+/*
+ * set up the physical settings of the WM9713
+ */
+static void wm9713_phy_init(struct wm97xx *wm)
+{
+	u16 dig1 = 0, dig2, dig3;
+
+	/* default values */
+	dig2 = WM97XX_DELAY(4) | WM97XX_SLT(5);
+	dig3 = WM9712_RPU(1);
+
+	/* rpu */
+	if (rpu) {
+		dig3 &= 0xffc0;
+		dig3 |= WM9712_RPU(rpu);
+		dev_info(wm->dev, "setting pen detect pull-up to %d Ohms\n",
+			 64000 / rpu);
+	}
+
+	/* Five wire panel? */
+	if (five_wire) {
+		dig3 |= WM9713_45W;
+		dev_info(wm->dev, "setting 5-wire touchscreen mode.");
+
+		if (pil) {
+			dev_warn(wm->dev,
+				 "Pressure measurement not supported in 5 "
+				 "wire mode, disabling\n");
+			pil = 0;
+		}
+	}
+
+	/* touchpanel pressure */
+	if (pil == 2) {
+		dig3 |= WM9712_PIL;
+		dev_info(wm->dev,
+			 "setting pressure measurement current to 400uA.");
+	} else if (pil)
+		dev_info(wm->dev,
+			 "setting pressure measurement current to 200uA.");
+	if (!pil)
+		pressure = 0;
+
+	/* sample settling delay */
+	if (delay < 0 || delay > 15) {
+		dev_info(wm->dev, "supplied delay out of range.");
+		delay = 4;
+		dev_info(wm->dev, "setting adc sample delay to %d u Secs.",
+			 delay_table[delay]);
+	}
+	dig2 &= 0xff0f;
+	dig2 |= WM97XX_DELAY(delay);
+
+	/* mask */
+	dig3 |= ((mask & 0x3) << 4);
+	if (coord)
+		dig3 |= WM9713_WAIT;
+
+	wm->misc = wm97xx_reg_read(wm, 0x5a);
+
+	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
+	wm97xx_reg_write(wm, AC97_GPIO_STICKY, 0x0);
+}
+
+static void wm9713_dig_enable(struct wm97xx *wm, int enable)
+{
+	u16 val;
+
+	if (enable) {
+		val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
+		wm97xx_reg_write(wm, AC97_EXTENDED_MID, val & 0x7fff);
+		wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] |
+				 WM97XX_PRP_DET_DIG);
+		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
+	} else {
+		wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] &
+					~WM97XX_PRP_DET_DIG);
+		val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
+		wm97xx_reg_write(wm, AC97_EXTENDED_MID, val | 0x8000);
+	}
+}
+
+static void wm9713_dig_restore(struct wm97xx *wm)
+{
+	wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig_save[0]);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig_save[1]);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig_save[2]);
+}
+
+static void wm9713_aux_prepare(struct wm97xx *wm)
+{
+	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
+	wm97xx_reg_write(wm, AC97_WM9713_DIG1, 0);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG2, 0);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG3, WM97XX_PRP_DET_DIG);
+}
+
+static inline int is_pden(struct wm97xx *wm)
+{
+	return wm->dig[2] & WM9713_PDEN;
+}
+
+/*
+ * Read a sample from the WM9713 adc in polling mode.
+ */
+static int wm9713_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
+{
+	u16 dig1;
+	int timeout = 5 * delay;
+	bool wants_pen = adcsel & WM97XX_PEN_DOWN;
+
+	if (wants_pen && !wm->pen_probably_down) {
+		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
+		if (!(data & WM97XX_PEN_DOWN))
+			return RC_PENUP;
+		wm->pen_probably_down = 1;
+	}
+
+	/* set up digitiser */
+	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
+	dig1 &= ~WM9713_ADCSEL_MASK;
+	/* WM97XX_ADCSEL_* channels need to be converted to WM9713 format */
+	dig1 |= 1 << ((adcsel & WM97XX_ADCSEL_MASK) >> 12);
+
+	if (wm->mach_ops && wm->mach_ops->pre_sample)
+		wm->mach_ops->pre_sample(adcsel);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1 | WM9713_POLL);
+
+	/* wait 3 AC97 time slots + delay for conversion */
+	poll_delay(delay);
+
+	/* wait for POLL to go low */
+	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL) &&
+		timeout) {
+		udelay(AC97_LINK_FRAME);
+		timeout--;
+	}
+
+	if (timeout <= 0) {
+		/* If PDEN is set, we can get a timeout when pen goes up */
+		if (is_pden(wm))
+			wm->pen_probably_down = 0;
+		else
+			dev_dbg(wm->dev, "adc sample timeout");
+		return RC_PENUP;
+	}
+
+	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
+	if (wm->mach_ops && wm->mach_ops->post_sample)
+		wm->mach_ops->post_sample(adcsel);
+
+	/* check we have correct sample */
+	if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
+		dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
+			adcsel & WM97XX_ADCSEL_MASK,
+			*sample & WM97XX_ADCSEL_MASK);
+		return RC_PENUP;
+	}
+
+	if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
+		wm->pen_probably_down = 0;
+		return RC_PENUP;
+	}
+
+	return RC_VALID;
+}
+
+/*
+ * Read a coordinate from the WM9713 adc in polling mode.
+ */
+static int wm9713_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
+{
+	u16 dig1;
+	int timeout = 5 * delay;
+
+	if (!wm->pen_probably_down) {
+		u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
+		if (!(val & WM97XX_PEN_DOWN))
+			return RC_PENUP;
+		wm->pen_probably_down = 1;
+	}
+
+	/* set up digitiser */
+	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
+	dig1 &= ~WM9713_ADCSEL_MASK;
+	if (pil)
+		dig1 |= WM9713_ADCSEL_PRES;
+
+	if (wm->mach_ops && wm->mach_ops->pre_sample)
+		wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG1,
+			 dig1 | WM9713_POLL | WM9713_COO);
+
+	/* wait 3 AC97 time slots + delay for conversion */
+	poll_delay(delay);
+	data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
+	/* wait for POLL to go low */
+	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
+	       && timeout) {
+		udelay(AC97_LINK_FRAME);
+		timeout--;
+	}
+
+	if (timeout <= 0) {
+		/* If PDEN is set, we can get a timeout when pen goes up */
+		if (is_pden(wm))
+			wm->pen_probably_down = 0;
+		else
+			dev_dbg(wm->dev, "adc sample timeout");
+		return RC_PENUP;
+	}
+
+	/* read back data */
+	data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
+	if (pil)
+		data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
+	else
+		data->p = DEFAULT_PRESSURE;
+
+	if (wm->mach_ops && wm->mach_ops->post_sample)
+		wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
+
+	/* check we have correct sample */
+	if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
+		goto err;
+	if (pil && !(data->p & WM97XX_ADCSEL_PRES))
+		goto err;
+
+	if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
+		wm->pen_probably_down = 0;
+		return RC_PENUP;
+	}
+	return RC_VALID;
+err:
+	return 0;
+}
+
+/*
+ * Sample the WM9713 touchscreen in polling mode
+ */
+static int wm9713_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
+{
+	int rc;
+
+	if (coord) {
+		rc = wm9713_poll_coord(wm, data);
+		if (rc != RC_VALID)
+			return rc;
+	} else {
+		rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
+		if (rc != RC_VALID)
+			return rc;
+		rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
+		if (rc != RC_VALID)
+			return rc;
+		if (pil) {
+			rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
+						&data->p);
+			if (rc != RC_VALID)
+				return rc;
+		} else
+			data->p = DEFAULT_PRESSURE;
+	}
+	return RC_VALID;
+}
+
+/*
+ * Enable WM9713 continuous mode, i.e. touch data is streamed across
+ * an AC97 slot
+ */
+static int wm9713_acc_enable(struct wm97xx *wm, int enable)
+{
+	u16 dig1, dig2, dig3;
+	int ret = 0;
+
+	dig1 = wm->dig[0];
+	dig2 = wm->dig[1];
+	dig3 = wm->dig[2];
+
+	if (enable) {
+		/* continuous mode */
+		if (wm->mach_ops->acc_startup &&
+			(ret = wm->mach_ops->acc_startup(wm)) < 0)
+			return ret;
+
+		dig1 &= ~WM9713_ADCSEL_MASK;
+		dig1 |= WM9713_CTC | WM9713_COO | WM9713_ADCSEL_X |
+			WM9713_ADCSEL_Y;
+		if (pil)
+			dig1 |= WM9713_ADCSEL_PRES;
+		dig2 &= ~(WM97XX_DELAY_MASK | WM97XX_SLT_MASK  |
+			WM97XX_CM_RATE_MASK);
+		dig2 |= WM97XX_SLEN | WM97XX_DELAY(delay) |
+		WM97XX_SLT(wm->acc_slot) | WM97XX_RATE(wm->acc_rate);
+		dig3 |= WM9713_PDEN;
+	} else {
+		dig1 &= ~(WM9713_CTC | WM9713_COO);
+		dig2 &= ~WM97XX_SLEN;
+		dig3 &= ~WM9713_PDEN;
+		if (wm->mach_ops->acc_shutdown)
+			wm->mach_ops->acc_shutdown(wm);
+	}
+
+	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
+	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
+
+	return ret;
+}
+
+struct wm97xx_codec_drv wm9713_codec = {
+	.id = WM9713_ID2,
+	.name = "wm9713",
+	.poll_sample = wm9713_poll_sample,
+	.poll_touch = wm9713_poll_touch,
+	.acc_enable = wm9713_acc_enable,
+	.phy_init = wm9713_phy_init,
+	.dig_enable = wm9713_dig_enable,
+	.dig_restore = wm9713_dig_restore,
+	.aux_prepare = wm9713_aux_prepare,
+};
+EXPORT_SYMBOL_GPL(wm9713_codec);
+
+/* Module information */
+MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
+MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
+MODULE_LICENSE("GPL");