From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- 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 | 521 ++++++++++ drivers/gpu/drm/mcde/mcde_dsi.c | 1238 ++++++++++++++++++++++++ drivers/gpu/drm/mcde/mcde_dsi_regs.h | 385 ++++++++ 9 files changed, 4607 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