From: Andrzej Hajda a.hajda@samsung.com
[ Upstream commit 6a3b45ada960ac475ec2b4103d43e57943b2b8d3 ]
MIXER on Exynos5 SoCs uses different synchronisation method than Exynos4 to update internal state (shadow registers). Apparently the driver implements it incorrectly. The rule should be as follows: - do not request updating registers until previous request was finished, ie. MXR_CFG_LAYER_UPDATE_COUNT must be 0. - before setting registers synchronisation on VSYNC should be turned off, ie. MXR_STATUS_SYNC_ENABLE should be reset, - after finishing MXR_STATUS_SYNC_ENABLE should be set again. The patch hopefully implements it correctly. Below sample kernel log from page fault caused by the bug:
[ 25.670038] exynos-sysmmu 14650000.sysmmu: 14450000.mixer: PAGE FAULT occurred at 0x2247b800 [ 25.677888] ------------[ cut here ]------------ [ 25.682164] kernel BUG at ../drivers/iommu/exynos-iommu.c:450! [ 25.687971] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM [ 25.693778] Modules linked in: [ 25.696816] CPU: 5 PID: 1553 Comm: fb-release_test Not tainted 5.0.0-rc7-01157-g5f86b1566bdd #136 [ 25.705646] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 25.711710] PC is at exynos_sysmmu_irq+0x1c0/0x264 [ 25.716470] LR is at lock_is_held_type+0x44/0x64
v2: added missing MXR_CFG_LAYER_UPDATE bit setting in mixer_enable_sync
Reported-by: Marian Mihailescu mihailescu2m@gmail.com Signed-off-by: Andrzej Hajda a.hajda@samsung.com Signed-off-by: Inki Dae inki.dae@samsung.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/exynos/exynos_mixer.c | 110 +++++++++++++++----------- 1 file changed, 66 insertions(+), 44 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c index 0573eab0e190..f35e4ab55b27 100644 --- a/drivers/gpu/drm/exynos/exynos_mixer.c +++ b/drivers/gpu/drm/exynos/exynos_mixer.c @@ -20,6 +20,7 @@ #include "regs-vp.h"
#include <linux/kernel.h> +#include <linux/ktime.h> #include <linux/spinlock.h> #include <linux/wait.h> #include <linux/i2c.h> @@ -352,15 +353,62 @@ static void mixer_cfg_vp_blend(struct mixer_context *ctx, unsigned int alpha) mixer_reg_write(ctx, MXR_VIDEO_CFG, val); }
-static void mixer_vsync_set_update(struct mixer_context *ctx, bool enable) +static bool mixer_is_synced(struct mixer_context *ctx) { - /* block update on vsync */ - mixer_reg_writemask(ctx, MXR_STATUS, enable ? - MXR_STATUS_SYNC_ENABLE : 0, MXR_STATUS_SYNC_ENABLE); + u32 base, shadow;
+ if (ctx->mxr_ver == MXR_VER_16_0_33_0 || + ctx->mxr_ver == MXR_VER_128_0_0_184) + return !(mixer_reg_read(ctx, MXR_CFG) & + MXR_CFG_LAYER_UPDATE_COUNT_MASK); + + if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags) && + vp_reg_read(ctx, VP_SHADOW_UPDATE)) + return false; + + base = mixer_reg_read(ctx, MXR_CFG); + shadow = mixer_reg_read(ctx, MXR_CFG_S); + if (base != shadow) + return false; + + base = mixer_reg_read(ctx, MXR_GRAPHIC_BASE(0)); + shadow = mixer_reg_read(ctx, MXR_GRAPHIC_BASE_S(0)); + if (base != shadow) + return false; + + base = mixer_reg_read(ctx, MXR_GRAPHIC_BASE(1)); + shadow = mixer_reg_read(ctx, MXR_GRAPHIC_BASE_S(1)); + if (base != shadow) + return false; + + return true; +} + +static int mixer_wait_for_sync(struct mixer_context *ctx) +{ + ktime_t timeout = ktime_add_us(ktime_get(), 100000); + + while (!mixer_is_synced(ctx)) { + usleep_range(1000, 2000); + if (ktime_compare(ktime_get(), timeout) > 0) + return -ETIMEDOUT; + } + return 0; +} + +static void mixer_disable_sync(struct mixer_context *ctx) +{ + mixer_reg_writemask(ctx, MXR_STATUS, 0, MXR_STATUS_SYNC_ENABLE); +} + +static void mixer_enable_sync(struct mixer_context *ctx) +{ + if (ctx->mxr_ver == MXR_VER_16_0_33_0 || + ctx->mxr_ver == MXR_VER_128_0_0_184) + mixer_reg_writemask(ctx, MXR_CFG, ~0, MXR_CFG_LAYER_UPDATE); + mixer_reg_writemask(ctx, MXR_STATUS, ~0, MXR_STATUS_SYNC_ENABLE); if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags)) - vp_reg_write(ctx, VP_SHADOW_UPDATE, enable ? - VP_SHADOW_UPDATE_ENABLE : 0); + vp_reg_write(ctx, VP_SHADOW_UPDATE, VP_SHADOW_UPDATE_ENABLE); }
static void mixer_cfg_scan(struct mixer_context *ctx, int width, int height) @@ -498,7 +546,6 @@ static void vp_video_buffer(struct mixer_context *ctx,
spin_lock_irqsave(&ctx->reg_slock, flags);
- vp_reg_write(ctx, VP_SHADOW_UPDATE, 1); /* interlace or progressive scan mode */ val = (test_bit(MXR_BIT_INTERLACE, &ctx->flags) ? ~0 : 0); vp_reg_writemask(ctx, VP_MODE, val, VP_MODE_LINE_SKIP); @@ -553,11 +600,6 @@ static void vp_video_buffer(struct mixer_context *ctx, vp_regs_dump(ctx); }
-static void mixer_layer_update(struct mixer_context *ctx) -{ - mixer_reg_writemask(ctx, MXR_CFG, ~0, MXR_CFG_LAYER_UPDATE); -} - static void mixer_graph_buffer(struct mixer_context *ctx, struct exynos_drm_plane *plane) { @@ -640,11 +682,6 @@ static void mixer_graph_buffer(struct mixer_context *ctx, mixer_cfg_layer(ctx, win, priority, true); mixer_cfg_gfx_blend(ctx, win, pixel_alpha, state->base.alpha);
- /* layer update mandatory for mixer 16.0.33.0 */ - if (ctx->mxr_ver == MXR_VER_16_0_33_0 || - ctx->mxr_ver == MXR_VER_128_0_0_184) - mixer_layer_update(ctx); - spin_unlock_irqrestore(&ctx->reg_slock, flags);
mixer_regs_dump(ctx); @@ -709,7 +746,7 @@ static void mixer_win_reset(struct mixer_context *ctx) static irqreturn_t mixer_irq_handler(int irq, void *arg) { struct mixer_context *ctx = arg; - u32 val, base, shadow; + u32 val;
spin_lock(&ctx->reg_slock);
@@ -723,26 +760,9 @@ static irqreturn_t mixer_irq_handler(int irq, void *arg) val &= ~MXR_INT_STATUS_VSYNC;
/* interlace scan need to check shadow register */ - if (test_bit(MXR_BIT_INTERLACE, &ctx->flags)) { - if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags) && - vp_reg_read(ctx, VP_SHADOW_UPDATE)) - goto out; - - base = mixer_reg_read(ctx, MXR_CFG); - shadow = mixer_reg_read(ctx, MXR_CFG_S); - if (base != shadow) - goto out; - - base = mixer_reg_read(ctx, MXR_GRAPHIC_BASE(0)); - shadow = mixer_reg_read(ctx, MXR_GRAPHIC_BASE_S(0)); - if (base != shadow) - goto out; - - base = mixer_reg_read(ctx, MXR_GRAPHIC_BASE(1)); - shadow = mixer_reg_read(ctx, MXR_GRAPHIC_BASE_S(1)); - if (base != shadow) - goto out; - } + if (test_bit(MXR_BIT_INTERLACE, &ctx->flags) + && !mixer_is_synced(ctx)) + goto out;
drm_crtc_handle_vblank(&ctx->crtc->base); } @@ -917,12 +937,14 @@ static void mixer_disable_vblank(struct exynos_drm_crtc *crtc)
static void mixer_atomic_begin(struct exynos_drm_crtc *crtc) { - struct mixer_context *mixer_ctx = crtc->ctx; + struct mixer_context *ctx = crtc->ctx;
- if (!test_bit(MXR_BIT_POWERED, &mixer_ctx->flags)) + if (!test_bit(MXR_BIT_POWERED, &ctx->flags)) return;
- mixer_vsync_set_update(mixer_ctx, false); + if (mixer_wait_for_sync(ctx)) + dev_err(ctx->dev, "timeout waiting for VSYNC\n"); + mixer_disable_sync(ctx); }
static void mixer_update_plane(struct exynos_drm_crtc *crtc, @@ -964,7 +986,7 @@ static void mixer_atomic_flush(struct exynos_drm_crtc *crtc) if (!test_bit(MXR_BIT_POWERED, &mixer_ctx->flags)) return;
- mixer_vsync_set_update(mixer_ctx, true); + mixer_enable_sync(mixer_ctx); exynos_crtc_handle_event(crtc); }
@@ -979,7 +1001,7 @@ static void mixer_enable(struct exynos_drm_crtc *crtc)
exynos_drm_pipe_clk_enable(crtc, true);
- mixer_vsync_set_update(ctx, false); + mixer_disable_sync(ctx);
mixer_reg_writemask(ctx, MXR_STATUS, ~0, MXR_STATUS_SOFT_RESET);
@@ -992,7 +1014,7 @@ static void mixer_enable(struct exynos_drm_crtc *crtc)
mixer_commit(ctx);
- mixer_vsync_set_update(ctx, true); + mixer_enable_sync(ctx);
set_bit(MXR_BIT_POWERED, &ctx->flags); }