From: Mark Yacoub markyacoub@google.com

[Why] vblank timestamp needs GPU high precision timestamp query to avoid using the current monotonic/gettimeofday timestamp as best estimate.

[How] Implement driver get_vblank_timestamp call which calls get_scanout_position which loops over the CRTC comps to find a component with get_scanout_position implemented. Implement get_scanout_position for DSI component.

Tested on: Jacuzzi (MT8183) Fixes: igt@kms_flip expected frametime standard deviation to be lower than 0.05%

Suggested-by: jason-jh.lin jason-jh.lin@mediatek.com Signed-off-byL Mark Yacoub markyacoub@chromium.org --- drivers/gpu/drm/mediatek/mtk_disp_drv.h | 4 ++ drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 48 ++++++++++++------ drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 1 + drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h | 18 +++++++ drivers/gpu/drm/mediatek/mtk_dsi.c | 55 +++++++++++++++++++++ 5 files changed, 112 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_drv.h b/drivers/gpu/drm/mediatek/mtk_disp_drv.h index 86c3068894b11..6c0f1acb2cc22 100644 --- a/drivers/gpu/drm/mediatek/mtk_disp_drv.h +++ b/drivers/gpu/drm/mediatek/mtk_disp_drv.h @@ -44,6 +44,10 @@ void mtk_dpi_stop(struct device *dev);

void mtk_dsi_ddp_start(struct device *dev); void mtk_dsi_ddp_stop(struct device *dev); +bool mtk_dsi_get_scanout_position(struct device *dev, bool in_vblank_irq, + int *vpos, int *hpos, ktime_t *stime, + ktime_t *etime, + const struct drm_display_mode *mode);

int mtk_gamma_clk_enable(struct device *dev); void mtk_gamma_clk_disable(struct device *dev); diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c index 798cce90351b6..5e4e8aa005d7c 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c @@ -674,25 +674,45 @@ static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc, } mtk_drm_crtc_update_config(mtk_crtc, !!mtk_crtc->event); } +static bool mtk_drm_crtc_get_scanout_position( + struct drm_crtc *crtc, bool in_vblank_irq, int *vpos, int *hpos, + ktime_t *stime, ktime_t *etime, const struct drm_display_mode *mode) +{ + struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc); + int i; + + if (!mtk_crtc->enabled) + return false; + + for (i = 0; i < mtk_crtc->ddp_comp_nr; i++) { + struct mtk_ddp_comp *comp = mtk_crtc->ddp_comp[i]; + if (mtk_ddp_comp_get_scanout_position(comp, in_vblank_irq, vpos, + hpos, stime, etime, mode)) + return true; + } + return false; +}

static const struct drm_crtc_funcs mtk_crtc_funcs = { - .set_config = drm_atomic_helper_set_config, - .page_flip = drm_atomic_helper_page_flip, - .destroy = mtk_drm_crtc_destroy, - .reset = mtk_drm_crtc_reset, - .atomic_duplicate_state = mtk_drm_crtc_duplicate_state, - .atomic_destroy_state = mtk_drm_crtc_destroy_state, - .enable_vblank = mtk_drm_crtc_enable_vblank, - .disable_vblank = mtk_drm_crtc_disable_vblank, + .set_config = drm_atomic_helper_set_config, + .page_flip = drm_atomic_helper_page_flip, + .destroy = mtk_drm_crtc_destroy, + .reset = mtk_drm_crtc_reset, + .atomic_duplicate_state = mtk_drm_crtc_duplicate_state, + .atomic_destroy_state = mtk_drm_crtc_destroy_state, + .enable_vblank = mtk_drm_crtc_enable_vblank, + .disable_vblank = mtk_drm_crtc_disable_vblank, + .get_vblank_timestamp = drm_crtc_vblank_helper_get_vblank_timestamp, };

static const struct drm_crtc_helper_funcs mtk_crtc_helper_funcs = { - .mode_fixup = mtk_drm_crtc_mode_fixup, - .mode_set_nofb = mtk_drm_crtc_mode_set_nofb, - .atomic_begin = mtk_drm_crtc_atomic_begin, - .atomic_flush = mtk_drm_crtc_atomic_flush, - .atomic_enable = mtk_drm_crtc_atomic_enable, - .atomic_disable = mtk_drm_crtc_atomic_disable, + .mode_fixup = mtk_drm_crtc_mode_fixup, + .mode_set_nofb = mtk_drm_crtc_mode_set_nofb, + .atomic_begin = mtk_drm_crtc_atomic_begin, + .atomic_flush = mtk_drm_crtc_atomic_flush, + .atomic_enable = mtk_drm_crtc_atomic_enable, + .atomic_disable = mtk_drm_crtc_atomic_disable, + .get_scanout_position = mtk_drm_crtc_get_scanout_position, };

static int mtk_drm_crtc_init(struct drm_device *drm, diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c index 5860533ee9532..1c5ac4ccdcd30 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c @@ -252,6 +252,7 @@ static const struct mtk_ddp_comp_funcs ddp_dpi = { static const struct mtk_ddp_comp_funcs ddp_dsi = { .start = mtk_dsi_ddp_start, .stop = mtk_dsi_ddp_stop, + .get_scanout_position = mtk_dsi_get_scanout_position, };

static const struct mtk_ddp_comp_funcs ddp_gamma = { diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h index 1b582262b682b..f1e6cee8175f7 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h @@ -16,6 +16,7 @@ struct drm_crtc; struct drm_device; struct mtk_plane_state; struct drm_crtc_state; +struct drm_display_mode;

enum mtk_ddp_comp_type { MTK_DISP_OVL, @@ -65,6 +66,10 @@ struct mtk_ddp_comp_funcs { void (*bgclr_in_off)(struct device *dev); void (*ctm_set)(struct device *dev, struct drm_crtc_state *state); + bool (*get_scanout_position)(struct device *dev, bool in_vblank_irq, + int *vpos, int *hpos, ktime_t *stime, + ktime_t *etime, + const struct drm_display_mode *mode); };

struct mtk_ddp_comp { @@ -184,6 +189,19 @@ static inline void mtk_ddp_ctm_set(struct mtk_ddp_comp *comp, comp->funcs->ctm_set(comp->dev, state); }

+static inline bool mtk_ddp_comp_get_scanout_position( + struct mtk_ddp_comp *comp, bool in_vblank_irq, int *vpos, int *hpos, + ktime_t *stime, ktime_t *etime, const struct drm_display_mode *mode) +{ + if (comp->funcs && comp->funcs->get_scanout_position) { + return comp->funcs->get_scanout_position(comp->dev, + in_vblank_irq, vpos, + hpos, stime, etime, + mode); + } + return false; +} + int mtk_ddp_comp_get_id(struct device_node *node, enum mtk_ddp_comp_type comp_type); unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c index 0ad7157660afa..1c2b95bcc3e9c 100644 --- a/drivers/gpu/drm/mediatek/mtk_dsi.c +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c @@ -3,6 +3,7 @@ * Copyright (c) 2015 MediaTek Inc. */

+#include <linux/bitfield.h> #include <linux/clk.h> #include <linux/component.h> #include <linux/iopoll.h> @@ -147,6 +148,9 @@

#define MMSYS_SW_RST_DSI_B BIT(25)

+#define DSI_INPUT_DEBUG 0x1D4 +#define INP_LINE_CNT GENMASK(29, 16) + #define NS_TO_CYCLE(n, c) ((n) / (c) + (((n) % (c)) ? 1 : 0))

#define MTK_DSI_HOST_IS_READ(type) \ @@ -1208,6 +1212,57 @@ static int mtk_dsi_probe(struct platform_device *pdev) return ret; }

+bool mtk_dsi_get_scanout_position(struct device *dev, bool in_vblank_irq, + int *vpos, int *hpos, ktime_t *stime, + ktime_t *etime, + const struct drm_display_mode *mode) +{ + struct mtk_dsi *dsi = dev_get_drvdata(dev); + int line_count = 0; + + int vsw = mode->crtc_vsync_end - mode->crtc_vsync_start; + int vbp = mode->crtc_vtotal - mode->crtc_vsync_end; + + int vactive_start = vsw + vbp + 1; + int vactive_end = vactive_start + mode->crtc_vdisplay; + int vfp_end = mode->crtc_vtotal; + + /* + * Target location for timestamp taken immediately before + * scanout position query. + */ + if (stime) + *stime = ktime_get(); + + line_count = + FIELD_GET(INP_LINE_CNT, readl(dsi->regs + DSI_INPUT_DEBUG)); + + /* + * Target location for timestamp taken immediately after + * scanout position query. + */ + if (etime) + *etime = ktime_get(); + + /* + * Returns vpos as a positive number while in active scanout area. + * Returns vpos as a negative number inside vblank, counting the number + * of scanlines to go until end of vblank, e.g., -1 means "one scanline + * until start of active scanout / end of vblank." + */ + if (line_count < vactive_start) + line_count -= vactive_start; + else if (line_count > vactive_end) + line_count = line_count - vfp_end - vactive_start; + else + line_count -= vactive_start; + + *vpos = line_count; + *hpos = 0; /* keep 0, this is informational */ + + return true; +} + static int mtk_dsi_remove(struct platform_device *pdev) { struct mtk_dsi *dsi = platform_get_drvdata(pdev);