From: Marek Szyprowski <m.szyprowski@samsung.com> stable inclusion from stable-v6.6.2 commit 2f56a02e2ab0118b553dfc53b05eb65ce760975c category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8IW7G Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 15f389da11257b806da75a070cfa41ca0cc15aae ] 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.szy... Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- drivers/gpu/drm/bridge/samsung-dsim.c | 18 ++++++++++++++++-- include/drm/bridge/samsung-dsim.h | 1 + 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c index 6f2ca74238d1..19bdb32dbc9a 100644 --- a/drivers/gpu/drm/bridge/samsung-dsim.c +++ b/drivers/gpu/drm/bridge/samsung-dsim.c @@ -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); diff --git a/include/drm/bridge/samsung-dsim.h b/include/drm/bridge/samsung-dsim.h index 05100e91ecb9..6fc9bb2979e4 100644 --- a/include/drm/bridge/samsung-dsim.h +++ b/include/drm/bridge/samsung-dsim.h @@ -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; -- 2.25.1