From 20c827683de05a6c7e7ae7fae586899690693251 Mon Sep 17 00:00:00 2001 From: Frieder Schrempf Date: Mon, 24 Jul 2023 17:16:32 +0200 Subject: [PATCH] drm: bridge: samsung-dsim: Fix init during host transfer In case the downstream bridge or panel uses DSI transfers before the DSI host was actually initialized through samsung_dsim_atomic_enable() which clears the stop state (LP11) mode, all transfers will fail. This happens with downstream bridges that are controlled by DSI commands such as the tc358762. As documented in [1] DSI hosts are expected to allow transfers outside the normal bridge enable/disable flow. To fix this make sure that stop state is cleared in samsung_dsim_host_transfer() which restores the previous behavior. We also factor out the common code to enable/disable stop state to samsung_dsim_set_stop_state(). [1] https://docs.kernel.org/gpu/drm-kms-helpers.html#mipi-dsi-bridge-operation Fixes: 0c14d3130654 ("drm: bridge: samsung-dsim: Fix i.MX8M enable flow to meet spec") Reported-by: Tim Harvey Signed-off-by: Frieder Schrempf Reviewed-by: Neil Armstrong Tested-by: Tim Harvey Signed-off-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/20230724151640.555490-1-frieder@fris.de --- drivers/gpu/drm/bridge/samsung-dsim.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c index 043b8109e64a..73ec60757dbc 100644 --- a/drivers/gpu/drm/bridge/samsung-dsim.c +++ b/drivers/gpu/drm/bridge/samsung-dsim.c @@ -1386,6 +1386,18 @@ static void samsung_dsim_disable_irq(struct samsung_dsim *dsi) disable_irq(dsi->irq); } +static void samsung_dsim_set_stop_state(struct samsung_dsim *dsi, bool enable) +{ + u32 reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG); + + if (enable) + reg |= DSIM_FORCE_STOP_STATE; + else + reg &= ~DSIM_FORCE_STOP_STATE; + + samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); +} + static int samsung_dsim_init(struct samsung_dsim *dsi) { const struct samsung_dsim_driver_data *driver_data = dsi->driver_data; @@ -1445,15 +1457,12 @@ static void samsung_dsim_atomic_enable(struct drm_bridge *bridge, struct drm_bridge_state *old_bridge_state) { struct samsung_dsim *dsi = bridge_to_dsi(bridge); - u32 reg; if (samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) { samsung_dsim_set_display_mode(dsi); samsung_dsim_set_display_enable(dsi, true); } else { - reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG); - reg &= ~DSIM_FORCE_STOP_STATE; - samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); + samsung_dsim_set_stop_state(dsi, false); } dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE; @@ -1463,16 +1472,12 @@ static void samsung_dsim_atomic_disable(struct drm_bridge *bridge, struct drm_bridge_state *old_bridge_state) { struct samsung_dsim *dsi = bridge_to_dsi(bridge); - u32 reg; if (!(dsi->state & DSIM_STATE_ENABLED)) return; - if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) { - reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG); - reg |= DSIM_FORCE_STOP_STATE; - samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); - } + if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) + samsung_dsim_set_stop_state(dsi, true); dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE; } @@ -1775,6 +1780,8 @@ static ssize_t samsung_dsim_host_transfer(struct mipi_dsi_host *host, if (ret) return ret; + samsung_dsim_set_stop_state(dsi, false); + ret = mipi_dsi_create_packet(&xfer.packet, msg); if (ret < 0) return ret;