[PATCH] drm/stm: ltdc: add support for CRC hashing feature
Raphaël Gallais-Pou
raphael.gallais-pou at foss.st.com
Fri Feb 11 02:46:20 PST 2022
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);
--
2.25.1
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