From 15f389da11257b806da75a070cfa41ca0cc15aae Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Wed, 9 Aug 2023 16:56:41 +0200 Subject: drm: bridge: samsung-dsim: Fix waiting for empty cmd transfer FIFO on older Exynos 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 Reviewed-by: Marek Vasut Signed-off-by: Robert Foss Link: https://patchwork.freedesktop.org/patch/msgid/20230809145641.3213210-1-m.szyprowski@samsung.com --- drivers/gpu/drm/bridge/samsung-dsim.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm') diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c index 732caafe5370..b1df91e37b1b 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); -- cgit