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drm: bridge: samsung-dsim: Fix waiting for empty cmd transfer FIFO on older Exynos

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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 ("drm: bridge: samsung-dsim: 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>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230809145641.3213210-1-m.szyprowski@samsung.com
This commit is contained in:
Marek Szyprowski 2023-08-09 16:56:41 +02:00 committed by Robert Foss
parent 96413b355a
commit 15f389da11
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GPG Key ID: 3EFD900F76D1D784
2 changed files with 17 additions and 2 deletions
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18
drivers/gpu/drm/bridge/samsung-dsim.c
View File

@ -413,6 +413,7 @@ 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 = {
@ -429,6 +430,7 @@ 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 = {
@ -1010,8 +1012,20 @@ 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);

1
include/drm/bridge/samsung-dsim.h
View File

@ -53,6 +53,7 @@ struct samsung_dsim_driver_data {
unsigned int plltmr_reg;
unsigned int has_freqband:1;
unsigned int has_clklane_stop:1;
unsigned int has_broken_fifoctrl_emptyhdr:1;
unsigned int num_clks;
unsigned int min_freq;
unsigned int max_freq;