[PATCH v4 4/4] drm/msm/dsi: Enable widebus for DSI

From: Jessica Zhang
Date: Tue Aug 22 2023 - 13:43:05 EST


DSI 6G v2.5.x+ supports a data-bus widen mode that allows DSI to send
48 bits of compressed data instead of 24.

Enable this mode whenever DSC is enabled for supported chipsets.

Signed-off-by: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/dsi/dsi.c | 2 +-
drivers/gpu/drm/msm/dsi/dsi.h | 1 +
drivers/gpu/drm/msm/dsi/dsi_host.c | 31 +++++++++++++++++++++++++++----
3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
index 4cf424b3509f..7327bfc06a84 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.c
+++ b/drivers/gpu/drm/msm/dsi/dsi.c
@@ -19,7 +19,7 @@ struct drm_dsc_config *msm_dsi_get_dsc_config(struct msm_dsi *msm_dsi)

bool msm_dsi_wide_bus_enabled(struct msm_dsi *msm_dsi)
{
- return false;
+ return msm_dsi_host_is_widebus_enabled(msm_dsi->host);
}

static int dsi_get_phy(struct msm_dsi *msm_dsi)
diff --git a/drivers/gpu/drm/msm/dsi/dsi.h b/drivers/gpu/drm/msm/dsi/dsi.h
index bd3763a5d723..a557d2c1aaff 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.h
+++ b/drivers/gpu/drm/msm/dsi/dsi.h
@@ -134,6 +134,7 @@ int dsi_calc_clk_rate_6g(struct msm_dsi_host *msm_host, bool is_bonded_dsi);
void msm_dsi_host_snapshot(struct msm_disp_state *disp_state, struct mipi_dsi_host *host);
void msm_dsi_host_test_pattern_en(struct mipi_dsi_host *host);
struct drm_dsc_config *msm_dsi_host_get_dsc_config(struct mipi_dsi_host *host);
+bool msm_dsi_host_is_widebus_enabled(struct mipi_dsi_host *host);

/* dsi phy */
struct msm_dsi_phy;
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 645927214871..267c7fda8854 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -710,6 +710,15 @@ static void dsi_ctrl_disable(struct msm_dsi_host *msm_host)
dsi_write(msm_host, REG_DSI_CTRL, 0);
}

+bool msm_dsi_host_is_widebus_enabled(struct mipi_dsi_host *host)
+{
+ struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
+
+ return msm_host->dsc &&
+ (msm_host->cfg_hnd->major == MSM_DSI_VER_MAJOR_6G &&
+ msm_host->cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V2_5_0);
+}
+
static void dsi_ctrl_enable(struct msm_dsi_host *msm_host,
struct msm_dsi_phy_shared_timings *phy_shared_timings, struct msm_dsi_phy *phy)
{
@@ -753,10 +762,16 @@ static void dsi_ctrl_enable(struct msm_dsi_host *msm_host,
data |= DSI_CMD_CFG1_INSERT_DCS_COMMAND;
dsi_write(msm_host, REG_DSI_CMD_CFG1, data);

- if (msm_host->cfg_hnd->major == MSM_DSI_VER_MAJOR_6G &&
- msm_host->cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V1_3) {
+ if (cfg_hnd->major == MSM_DSI_VER_MAJOR_6G) {
data = dsi_read(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2);
- data |= DSI_CMD_MODE_MDP_CTRL2_BURST_MODE;
+
+ if (cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V1_3)
+ data |= DSI_CMD_MODE_MDP_CTRL2_BURST_MODE;
+
+ /* TODO: Allow for video-mode support once tested/fixed */
+ if (msm_dsi_host_is_widebus_enabled(&msm_host->base))
+ data |= DSI_CMD_MODE_MDP_CTRL2_DATABUS_WIDEN;
+
dsi_write(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2, data);
}
}
@@ -894,6 +909,7 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
u32 hdisplay = mode->hdisplay;
u32 wc;
int ret;
+ bool widebus_enabled = msm_dsi_host_is_widebus_enabled(&msm_host->base);

DBG("");

@@ -914,6 +930,7 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)

if (msm_host->dsc) {
struct drm_dsc_config *dsc = msm_host->dsc;
+ u32 bytes_per_pclk;

/* update dsc params with timing params */
if (!dsc || !mode->hdisplay || !mode->vdisplay) {
@@ -937,7 +954,13 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
* pulse width same
*/
h_total -= hdisplay;
- hdisplay = DIV_ROUND_UP(msm_dsc_get_bytes_per_line(msm_host->dsc), 3);
+ if (widebus_enabled && !(msm_host->mode_flags & MIPI_DSI_MODE_VIDEO))
+ bytes_per_pclk = 6;
+ else
+ bytes_per_pclk = 3;
+
+ hdisplay = DIV_ROUND_UP(msm_dsc_get_bytes_per_line(msm_host->dsc), bytes_per_pclk);
+
h_total += hdisplay;
ha_end = ha_start + hdisplay;
}

--
2.42.0