@@ -412,6 +412,7 @@ static const struct samsung_dsim_driver_data exynos3_dsi_driver_data = {
.m_min = 41,
.m_max = 125,
.min_freq = 500,
+ .has_broken_fifoctrl_emptyhdr = 1,
};
static const struct samsung_dsim_driver_data exynos4_dsi_driver_data = {
@@ -428,6 +429,7 @@ static const struct samsung_dsim_driver_data exynos4_dsi_driver_data = {
.m_min = 41,
.m_max = 125,
.min_freq = 500,
+ .has_broken_fifoctrl_emptyhdr = 1,
};
static const struct samsung_dsim_driver_data exynos5_dsi_driver_data = {
@@ -1009,8 +1011,20 @@ static int samsung_dsim_wait_for_hdr_fifo(struct samsung_dsim *dsi)
do {
u32 reg = samsung_dsim_read(dsi, DSIM_FIFOCTRL_REG);
- if (reg & DSIM_SFR_HEADER_EMPTY)
- return 0;
+ if (!dsi->driver_data->has_broken_fifoctrl_emptyhdr) {
+ if (reg & DSIM_SFR_HEADER_EMPTY)
+ return 0;
+ } else {
+ if (!(reg & DSIM_SFR_HEADER_FULL)) {
+ /*
+ * Wait a little bit, so the pending data can
+ * actually leave the FIFO to avoid overflow.
+ */
+ if (!cond_resched())
+ usleep_range(950, 1050);
+ return 0;
+ }
+ }
if (!cond_resched())
usleep_range(950, 1050);
@@ -62,6 +62,7 @@ struct samsung_dsim_driver_data {
const unsigned int *reg_values;
u16 m_min;
u16 m_max;
+ unsigned int has_broken_fifoctrl_emptyhdr;
};
struct samsung_dsim_host_ops {
Samsung DSIM used in older Exynos SoCs (like Exynos 4210, 4x12, 3250) doesn't report empty level of packer header FIFO. In case of those SoCs, use the old way of waiting for empty command tranfsfer FIFO, removed recently by commit 14806c641582 ("Drain command transfer FIFO before transfer"). Fixes: 14806c641582 ("drm: bridge: samsung-dsim: Drain command transfer FIFO before transfer") Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Marek Vasut <marex@denx.de> --- v3: - fixed 'fixes' tag, added reviewed-by v2: - added additional delay when workaround is used as suggested by Marek Vasut v1: https://lore.kernel.org/all/20230718131859.3114135-1-m.szyprowski@samsung.com/ --- drivers/gpu/drm/bridge/samsung-dsim.c | 18 ++++++++++++++++-- include/drm/bridge/samsung-dsim.h | 1 + 2 files changed, 17 insertions(+), 2 deletions(-)