From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/gpu/drm/mcde/Kconfig | 18 + drivers/gpu/drm/mcde/Makefile | 3 + drivers/gpu/drm/mcde/mcde_clk_div.c | 196 ++++ drivers/gpu/drm/mcde/mcde_display.c | 1523 ++++++++++++++++++++++++++++++ drivers/gpu/drm/mcde/mcde_display_regs.h | 605 ++++++++++++ drivers/gpu/drm/mcde/mcde_drm.h | 118 +++ drivers/gpu/drm/mcde/mcde_drv.c | 522 ++++++++++ drivers/gpu/drm/mcde/mcde_dsi.c | 1242 ++++++++++++++++++++++++ drivers/gpu/drm/mcde/mcde_dsi_regs.h | 385 ++++++++ 9 files changed, 4612 insertions(+) create mode 100644 drivers/gpu/drm/mcde/Kconfig create mode 100644 drivers/gpu/drm/mcde/Makefile create mode 100644 drivers/gpu/drm/mcde/mcde_clk_div.c create mode 100644 drivers/gpu/drm/mcde/mcde_display.c create mode 100644 drivers/gpu/drm/mcde/mcde_display_regs.h create mode 100644 drivers/gpu/drm/mcde/mcde_drm.h create mode 100644 drivers/gpu/drm/mcde/mcde_drv.c create mode 100644 drivers/gpu/drm/mcde/mcde_dsi.c create mode 100644 drivers/gpu/drm/mcde/mcde_dsi_regs.h (limited to 'drivers/gpu/drm/mcde') diff --git a/drivers/gpu/drm/mcde/Kconfig b/drivers/gpu/drm/mcde/Kconfig new file mode 100644 index 000000000..3516c8d2a --- /dev/null +++ b/drivers/gpu/drm/mcde/Kconfig @@ -0,0 +1,18 @@ +config DRM_MCDE + tristate "DRM Support for ST-Ericsson MCDE (Multichannel Display Engine)" + depends on DRM + depends on CMA + depends on ARM || COMPILE_TEST + depends on OF + depends on COMMON_CLK + select MFD_SYSCON + select DRM_CLIENT_SELECTION + select DRM_MIPI_DSI + select DRM_BRIDGE + select DRM_PANEL_BRIDGE + select DRM_KMS_HELPER + select DRM_GEM_DMA_HELPER + help + Choose this option for DRM support for the ST-Ericsson MCDE + Multi-Channel Display Engine. + If M is selected the module will be called mcde_drm. diff --git a/drivers/gpu/drm/mcde/Makefile b/drivers/gpu/drm/mcde/Makefile new file mode 100644 index 000000000..15d9c89a3 --- /dev/null +++ b/drivers/gpu/drm/mcde/Makefile @@ -0,0 +1,3 @@ +mcde_drm-y += mcde_drv.o mcde_dsi.o mcde_clk_div.o mcde_display.o + +obj-$(CONFIG_DRM_MCDE) += mcde_drm.o diff --git a/drivers/gpu/drm/mcde/mcde_clk_div.c b/drivers/gpu/drm/mcde/mcde_clk_div.c new file mode 100644 index 000000000..8c5af2677 --- /dev/null +++ b/drivers/gpu/drm/mcde/mcde_clk_div.c @@ -0,0 +1,196 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include + +#include "mcde_drm.h" +#include "mcde_display_regs.h" + +/* The MCDE internal clock dividers for FIFO A and B */ +struct mcde_clk_div { + struct clk_hw hw; + struct mcde *mcde; + u32 cr; + u32 cr_div; +}; + +static int mcde_clk_div_enable(struct clk_hw *hw) +{ + struct mcde_clk_div *cdiv = container_of(hw, struct mcde_clk_div, hw); + struct mcde *mcde = cdiv->mcde; + u32 val; + + spin_lock(&mcde->fifo_crx1_lock); + val = readl(mcde->regs + cdiv->cr); + /* + * Select the PLL72 (LCD) clock as parent + * FIXME: implement other parents. + */ + val &= ~MCDE_CRX1_CLKSEL_MASK; + val |= MCDE_CRX1_CLKSEL_CLKPLL72 << MCDE_CRX1_CLKSEL_SHIFT; + /* Internal clock */ + val |= MCDE_CRA1_CLKTYPE_TVXCLKSEL1; + + /* Clear then set the divider */ + val &= ~(MCDE_CRX1_BCD | MCDE_CRX1_PCD_MASK); + val |= cdiv->cr_div; + + writel(val, mcde->regs + cdiv->cr); + spin_unlock(&mcde->fifo_crx1_lock); + + return 0; +} + +static int mcde_clk_div_choose_div(struct clk_hw *hw, unsigned long rate, + unsigned long *prate, bool set_parent) +{ + int best_div = 1, div; + struct clk_hw *parent = clk_hw_get_parent(hw); + unsigned long best_prate = 0; + unsigned long best_diff = ~0ul; + int max_div = (1 << MCDE_CRX1_PCD_BITS) - 1; + + for (div = 1; div < max_div; div++) { + unsigned long this_prate, div_rate, diff; + + if (set_parent) + this_prate = clk_hw_round_rate(parent, rate * div); + else + this_prate = *prate; + div_rate = DIV_ROUND_UP_ULL(this_prate, div); + diff = abs(rate - div_rate); + + if (diff < best_diff) { + best_div = div; + best_diff = diff; + best_prate = this_prate; + } + } + + *prate = best_prate; + return best_div; +} + +static int mcde_clk_div_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + int div = mcde_clk_div_choose_div(hw, req->rate, + &req->best_parent_rate, true); + + req->rate = DIV_ROUND_UP_ULL(req->best_parent_rate, div); + + return 0; +} + +static unsigned long mcde_clk_div_recalc_rate(struct clk_hw *hw, + unsigned long prate) +{ + struct mcde_clk_div *cdiv = container_of(hw, struct mcde_clk_div, hw); + struct mcde *mcde = cdiv->mcde; + u32 cr; + int div; + + /* + * If the MCDE is not powered we can't access registers. + * It will come up with 0 in the divider register bits, which + * means "divide by 2". + */ + if (!regulator_is_enabled(mcde->epod)) + return DIV_ROUND_UP_ULL(prate, 2); + + cr = readl(mcde->regs + cdiv->cr); + if (cr & MCDE_CRX1_BCD) + return prate; + + /* 0 in the PCD means "divide by 2", 1 means "divide by 3" etc */ + div = cr & MCDE_CRX1_PCD_MASK; + div += 2; + + return DIV_ROUND_UP_ULL(prate, div); +} + +static int mcde_clk_div_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long prate) +{ + struct mcde_clk_div *cdiv = container_of(hw, struct mcde_clk_div, hw); + int div = mcde_clk_div_choose_div(hw, rate, &prate, false); + u32 cr = 0; + + /* + * We cache the CR bits to set the divide in the state so that + * we can call this before we can even write to the hardware. + */ + if (div == 1) { + /* Bypass clock divider */ + cr |= MCDE_CRX1_BCD; + } else { + div -= 2; + cr |= div & MCDE_CRX1_PCD_MASK; + } + cdiv->cr_div = cr; + + return 0; +} + +static const struct clk_ops mcde_clk_div_ops = { + .enable = mcde_clk_div_enable, + .recalc_rate = mcde_clk_div_recalc_rate, + .determine_rate = mcde_clk_div_determine_rate, + .set_rate = mcde_clk_div_set_rate, +}; + +int mcde_init_clock_divider(struct mcde *mcde) +{ + struct device *dev = mcde->dev; + struct mcde_clk_div *fifoa; + struct mcde_clk_div *fifob; + const char *parent_name; + struct clk_init_data fifoa_init = { + .name = "fifoa", + .ops = &mcde_clk_div_ops, + .parent_names = &parent_name, + .num_parents = 1, + .flags = CLK_SET_RATE_PARENT, + }; + struct clk_init_data fifob_init = { + .name = "fifob", + .ops = &mcde_clk_div_ops, + .parent_names = &parent_name, + .num_parents = 1, + .flags = CLK_SET_RATE_PARENT, + }; + int ret; + + spin_lock_init(&mcde->fifo_crx1_lock); + parent_name = __clk_get_name(mcde->lcd_clk); + + /* Allocate 2 clocks */ + fifoa = devm_kzalloc(dev, sizeof(*fifoa), GFP_KERNEL); + if (!fifoa) + return -ENOMEM; + fifob = devm_kzalloc(dev, sizeof(*fifob), GFP_KERNEL); + if (!fifob) + return -ENOMEM; + + fifoa->mcde = mcde; + fifoa->cr = MCDE_CRA1; + fifoa->hw.init = &fifoa_init; + ret = devm_clk_hw_register(dev, &fifoa->hw); + if (ret) { + dev_err(dev, "error registering FIFO A clock divider\n"); + return ret; + } + mcde->fifoa_clk = fifoa->hw.clk; + + fifob->mcde = mcde; + fifob->cr = MCDE_CRB1; + fifob->hw.init = &fifob_init; + ret = devm_clk_hw_register(dev, &fifob->hw); + if (ret) { + dev_err(dev, "error registering FIFO B clock divider\n"); + return ret; + } + mcde->fifob_clk = fifob->hw.clk; + + return 0; +} diff --git a/drivers/gpu/drm/mcde/mcde_display.c b/drivers/gpu/drm/mcde/mcde_display.c new file mode 100644 index 000000000..257a6e84d --- /dev/null +++ b/drivers/gpu/drm/mcde/mcde_display.c @@ -0,0 +1,1523 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 Linus Walleij + * Parts of this file were based on the MCDE driver by Marcus Lorentzon + * (C) ST-Ericsson SA 2013 + */ +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include