[PATCH] drm/stm: ltdc: add support for CRC hashing feature
yannick Fertre
yannick.fertre at foss.st.com
Tue Feb 22 01:21:30 PST 2022
Hi Raphael,
thanks for the patch.
Acked-by: Yannick Fertre <yannick.fertre at foss.st.com>
Best regards
On 2/11/22 11:46, Raphaël Gallais-Pou wrote:
> From: Raphael Gallais-Pou <raphael.gallais-pou at foss.st.com>
>
> This patch adds the CRC hashing feature supported by some recent hardware
> versions of the LTDC. This is useful for test suite such as IGT-GPU-tools
> [1] where a CRTC output frame can be compared to a test reference frame
> thanks to their respective CRC hash.
>
> [1] https://cgit.freedesktop.org/drm/igt-gpu-tools
>
> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou at foss.st.com>
> ---
> drivers/gpu/drm/stm/ltdc.c | 104 +++++++++++++++++++++++++++++++++++--
> drivers/gpu/drm/stm/ltdc.h | 3 ++
> 2 files changed, 104 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index 5eeb32c9c9ce..b29476aec3a1 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -77,6 +77,7 @@
> #define LTDC_CPSR 0x0044 /* Current Position Status */
> #define LTDC_CDSR 0x0048 /* Current Display Status */
> #define LTDC_EDCR 0x0060 /* External Display Control */
> +#define LTDC_CCRCR 0x007C /* Computed CRC value */
> #define LTDC_FUT 0x0090 /* Fifo underrun Threshold */
>
> /* Layer register offsets */
> @@ -121,6 +122,7 @@
>
> #define GCR_LTDCEN BIT(0) /* LTDC ENable */
> #define GCR_DEN BIT(16) /* Dither ENable */
> +#define GCR_CRCEN BIT(19) /* CRC ENable */
> #define GCR_PCPOL BIT(28) /* Pixel Clock POLarity-Inverted */
> #define GCR_DEPOL BIT(29) /* Data Enable POLarity-High */
> #define GCR_VSPOL BIT(30) /* Vertical Synchro POLarity-High */
> @@ -227,6 +229,13 @@
>
> #define NB_PF 8 /* Max nb of HW pixel format */
>
> +/*
> + * Skip the first value and the second in case CRC was enabled during
> + * the thread irq. This is to be sure CRC value is relevant for the
> + * frame.
> + */
> +#define CRC_SKIP_FRAMES 2
> +
> enum ltdc_pix_fmt {
> PF_NONE,
> /* RGB formats */
> @@ -664,6 +673,26 @@ static inline void ltdc_set_ycbcr_coeffs(struct drm_plane *plane)
> ltdc_ycbcr2rgb_coeffs[enc][ran][1]);
> }
>
> +static inline void ltdc_irq_crc_handle(struct ltdc_device *ldev,
> + struct drm_crtc *crtc)
> +{
> + u32 crc;
> + int ret;
> +
> + if (ldev->crc_skip_count < CRC_SKIP_FRAMES) {
> + ldev->crc_skip_count++;
> + return;
> + }
> +
> + /* Get the CRC of the frame */
> + ret = regmap_read(ldev->regmap, LTDC_CCRCR, &crc);
> + if (ret)
> + return;
> +
> + /* Report to DRM the CRC (hw dependent feature) */
> + drm_crtc_add_crc_entry(crtc, true, drm_crtc_accurate_vblank_count(crtc), &crc);
> +}
> +
> static irqreturn_t ltdc_irq_thread(int irq, void *arg)
> {
> struct drm_device *ddev = arg;
> @@ -671,9 +700,14 @@ static irqreturn_t ltdc_irq_thread(int irq, void *arg)
> struct drm_crtc *crtc = drm_crtc_from_index(ddev, 0);
>
> /* Line IRQ : trigger the vblank event */
> - if (ldev->irq_status & ISR_LIF)
> + if (ldev->irq_status & ISR_LIF) {
> drm_crtc_handle_vblank(crtc);
>
> + /* Early return if CRC is not active */
> + if (ldev->crc_active)
> + ltdc_irq_crc_handle(ldev, crtc);
> + }
> +
> /* Save FIFO Underrun & Transfer Error status */
> mutex_lock(&ldev->err_lock);
> if (ldev->irq_status & ISR_FUIF)
> @@ -1079,6 +1113,48 @@ static void ltdc_crtc_disable_vblank(struct drm_crtc *crtc)
> regmap_clear_bits(ldev->regmap, LTDC_IER, IER_LIE);
> }
>
> +static int ltdc_crtc_set_crc_source(struct drm_crtc *crtc, const char *source)
> +{
> + struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> + int ret;
> +
> + DRM_DEBUG_DRIVER("\n");
> +
> + if (!crtc)
> + return -ENODEV;
> +
> + if (source && strcmp(source, "auto") == 0) {
> + ldev->crc_active = true;
> + ret = regmap_set_bits(ldev->regmap, LTDC_GCR, GCR_CRCEN);
> + } else if (!source) {
> + ldev->crc_active = false;
> + ret = regmap_clear_bits(ldev->regmap, LTDC_GCR, GCR_CRCEN);
> + } else {
> + ret = -EINVAL;
> + }
> +
> + ldev->crc_skip_count = 0;
> + return ret;
> +}
> +
> +static int ltdc_crtc_verify_crc_source(struct drm_crtc *crtc,
> + const char *source, size_t *values_cnt)
> +{
> + DRM_DEBUG_DRIVER("\n");
> +
> + if (!crtc)
> + return -ENODEV;
> +
> + if (source && strcmp(source, "auto") != 0) {
> + DRM_DEBUG_DRIVER("Unknown CRC source %s for %s\n",
> + source, crtc->name);
> + return -EINVAL;
> + }
> +
> + *values_cnt = 1;
> + return 0;
> +}
> +
> static const struct drm_crtc_funcs ltdc_crtc_funcs = {
> .destroy = drm_crtc_cleanup,
> .set_config = drm_atomic_helper_set_config,
> @@ -1091,6 +1167,20 @@ static const struct drm_crtc_funcs ltdc_crtc_funcs = {
> .get_vblank_timestamp = drm_crtc_vblank_helper_get_vblank_timestamp,
> };
>
> +static const struct drm_crtc_funcs ltdc_crtc_with_crc_support_funcs = {
> + .destroy = drm_crtc_cleanup,
> + .set_config = drm_atomic_helper_set_config,
> + .page_flip = drm_atomic_helper_page_flip,
> + .reset = drm_atomic_helper_crtc_reset,
> + .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
> + .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
> + .enable_vblank = ltdc_crtc_enable_vblank,
> + .disable_vblank = ltdc_crtc_disable_vblank,
> + .get_vblank_timestamp = drm_crtc_vblank_helper_get_vblank_timestamp,
> + .set_crc_source = ltdc_crtc_set_crc_source,
> + .verify_crc_source = ltdc_crtc_verify_crc_source,
> +};
> +
> /*
> * DRM_PLANE
> */
> @@ -1478,8 +1568,13 @@ static int ltdc_crtc_init(struct drm_device *ddev, struct drm_crtc *crtc)
>
> drm_plane_create_zpos_immutable_property(primary, 0);
>
> - ret = drm_crtc_init_with_planes(ddev, crtc, primary, NULL,
> - <dc_crtc_funcs, NULL);
> + /* Init CRTC according to its hardware features */
> + if (ldev->caps.crc)
> + ret = drm_crtc_init_with_planes(ddev, crtc, primary, NULL,
> + <dc_crtc_with_crc_support_funcs, NULL);
> + else
> + ret = drm_crtc_init_with_planes(ddev, crtc, primary, NULL,
> + <dc_crtc_funcs, NULL);
> if (ret) {
> DRM_ERROR("Can not initialize CRTC\n");
> goto cleanup;
> @@ -1629,6 +1724,7 @@ static int ltdc_get_caps(struct drm_device *ddev)
> ldev->caps.ycbcr_input = false;
> ldev->caps.ycbcr_output = false;
> ldev->caps.plane_reg_shadow = false;
> + ldev->caps.crc = false;
> break;
> case HWVER_20101:
> ldev->caps.layer_ofs = LAY_OFS_0;
> @@ -1643,6 +1739,7 @@ static int ltdc_get_caps(struct drm_device *ddev)
> ldev->caps.ycbcr_input = false;
> ldev->caps.ycbcr_output = false;
> ldev->caps.plane_reg_shadow = false;
> + ldev->caps.crc = false;
> break;
> case HWVER_40100:
> ldev->caps.layer_ofs = LAY_OFS_1;
> @@ -1657,6 +1754,7 @@ static int ltdc_get_caps(struct drm_device *ddev)
> ldev->caps.ycbcr_input = true;
> ldev->caps.ycbcr_output = true;
> ldev->caps.plane_reg_shadow = true;
> + ldev->caps.crc = true;
> break;
> default:
> return -ENODEV;
> diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
> index 6968d1ca5149..59fc5d1bbbab 100644
> --- a/drivers/gpu/drm/stm/ltdc.h
> +++ b/drivers/gpu/drm/stm/ltdc.h
> @@ -27,6 +27,7 @@ struct ltdc_caps {
> bool ycbcr_input; /* ycbcr input converter supported */
> bool ycbcr_output; /* ycbcr output converter supported */
> bool plane_reg_shadow; /* plane shadow registers ability */
> + bool crc; /* cyclic redundancy check supported */
> };
>
> #define LTDC_MAX_LAYER 4
> @@ -46,6 +47,8 @@ struct ltdc_device {
> u32 irq_status;
> struct fps_info plane_fpsi[LTDC_MAX_LAYER];
> struct drm_atomic_state *suspend_state;
> + int crc_skip_count;
> + bool crc_active;
> };
>
> int ltdc_load(struct drm_device *ddev);
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