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Subject[PATCH v5 15/80] drm/vc4: crtc: Add FIFO depth to vc4_crtc_data
Date
Not all pixelvalve FIFOs in vc5 have the same depth, so we need to add that
to our vc4_crtc_data structure to be able to compute the fill level
properly later on.

Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
drivers/gpu/drm/vc4/vc4_crtc.c | 20 +++++++++++++++++---
drivers/gpu/drm/vc4/vc4_drv.h | 3 +++
2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index b7e47ce1476c..2c64efd2d3d9 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -206,10 +206,21 @@ void vc4_crtc_destroy(struct drm_crtc *crtc)
drm_crtc_cleanup(crtc);
}

-static u32 vc4_get_fifo_full_level(u32 format)
+static u32 vc4_get_fifo_full_level(struct vc4_crtc *vc4_crtc, u32 format)
{
- static const u32 fifo_len_bytes = 64;
+ const struct vc4_pv_data *pv_data = vc4_crtc_to_vc4_pv_data(vc4_crtc);
+ u32 fifo_len_bytes = pv_data->fifo_depth;

+ /*
+ * Pixels are pulled from the HVS if the number of bytes is
+ * lower than the FIFO full level.
+ *
+ * The latency of the pixel fetch mechanism is 6 pixels, so we
+ * need to convert those 6 pixels in bytes, depending on the
+ * format, and then subtract that from the length of the FIFO
+ * to make sure we never end up in a situation where the FIFO
+ * is full.
+ */
switch (format) {
case PV_CONTROL_FORMAT_DSIV_16:
case PV_CONTROL_FORMAT_DSIC_16:
@@ -326,7 +337,7 @@ static void vc4_crtc_config_pv(struct drm_crtc *crtc)

CRTC_WRITE(PV_CONTROL,
VC4_SET_FIELD(format, PV_CONTROL_FORMAT) |
- VC4_SET_FIELD(vc4_get_fifo_full_level(format),
+ VC4_SET_FIELD(vc4_get_fifo_full_level(vc4_crtc, format),
PV_CONTROL_FIFO_LEVEL) |
VC4_SET_FIELD(pixel_rep - 1, PV_CONTROL_PIXEL_REP) |
PV_CONTROL_CLR_AT_START |
@@ -785,6 +796,7 @@ static const struct vc4_pv_data bcm2835_pv0_data = {
.hvs_output = 0,
},
.debugfs_name = "crtc0_regs",
+ .fifo_depth = 64,
.pixels_per_clock = 1,
.encoder_types = {
[PV_CONTROL_CLK_SELECT_DSI] = VC4_ENCODER_TYPE_DSI0,
@@ -798,6 +810,7 @@ static const struct vc4_pv_data bcm2835_pv1_data = {
.hvs_output = 2,
},
.debugfs_name = "crtc1_regs",
+ .fifo_depth = 64,
.pixels_per_clock = 1,
.encoder_types = {
[PV_CONTROL_CLK_SELECT_DSI] = VC4_ENCODER_TYPE_DSI1,
@@ -811,6 +824,7 @@ static const struct vc4_pv_data bcm2835_pv2_data = {
.hvs_output = 1,
},
.debugfs_name = "crtc2_regs",
+ .fifo_depth = 64,
.pixels_per_clock = 1,
.encoder_types = {
[PV_CONTROL_CLK_SELECT_DPI_SMI_HDMI] = VC4_ENCODER_TYPE_HDMI,
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 9e81ad8331f1..179010b9a010 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -457,6 +457,9 @@ struct vc4_crtc_data {
struct vc4_pv_data {
struct vc4_crtc_data base;

+ /* Depth of the PixelValve FIFO in bytes */
+ unsigned int fifo_depth;
+
/* Number of pixels output per clock period */
u8 pixels_per_clock;

--
git-series 0.9.1
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