[v2] drm/i915: Add support for Video Burst Mode for MIPI DSI

Shobhit Kumar
2014-07-30T14:53:06Z

v2: Updated the error log as suggested by Imre

Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
---
drivers/gpu/drm/i915/intel_bios.h | 3 ++-
drivers/gpu/drm/i915/intel_dsi.c | 22 ++++++++++-------
drivers/gpu/drm/i915/intel_dsi.h | 2 ++
drivers/gpu/drm/i915/intel_dsi_panel_vbt.c | 38 ++++++++++++++++++++++++++++--
drivers/gpu/drm/i915/intel_dsi_pll.c | 9 +++----
5 files changed, 57 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index b986677..905999b 100644
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -802,7 +802,8 @@ struct mipi_config {

u16 rsvd4;

- u8 rsvd5[5];
+ u8 rsvd5;
+ u32 target_burst_mode_freq;
u32 dsi_ddr_clk;
u32 bridge_ref_clk;

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 670c29a..aea8f33 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -423,9 +423,11 @@ static u16 txclkesc(u32 divider, unsigned int us)
}

/* return pixels in terms of txbyteclkhs */
-static u16 txbyteclkhs(u16 pixels, int bpp, int lane_count)
+static u16 txbyteclkhs(u16 pixels, int bpp, int lane_count,
+ u16 burst_mode_ratio)
{
- return DIV_ROUND_UP(DIV_ROUND_UP(pixels * bpp, 8), lane_count);
+ return DIV_ROUND_UP(DIV_ROUND_UP(pixels * bpp * burst_mode_ratio,
+ 8 * 100), lane_count);
}

static void set_dsi_timings(struct drm_encoder *encoder,
@@ -451,10 +453,12 @@ static void set_dsi_timings(struct drm_encoder *encoder,
vbp = mode->vtotal - mode->vsync_end;

/* horizontal values are in terms of high speed byte clock */
- hactive = txbyteclkhs(hactive, bpp, lane_count);
- hfp = txbyteclkhs(hfp, bpp, lane_count);
- hsync = txbyteclkhs(hsync, bpp, lane_count);
- hbp = txbyteclkhs(hbp, bpp, lane_count);
+ hactive = txbyteclkhs(hactive, bpp, lane_count,
+ intel_dsi->burst_mode_ratio);
+ hfp = txbyteclkhs(hfp, bpp, lane_count, intel_dsi->burst_mode_ratio);
+ hsync = txbyteclkhs(hsync, bpp, lane_count,
+ intel_dsi->burst_mode_ratio);
+ hbp = txbyteclkhs(hbp, bpp, lane_count, intel_dsi->burst_mode_ratio);

I915_WRITE(MIPI_HACTIVE_AREA_COUNT(pipe), hactive);
I915_WRITE(MIPI_HFP_COUNT(pipe), hfp);
@@ -541,12 +545,14 @@ static void intel_dsi_prepare(struct intel_encoder *intel_encoder)
intel_dsi->video_mode_format == VIDEO_MODE_BURST) {
I915_WRITE(MIPI_HS_TX_TIMEOUT(pipe),
txbyteclkhs(adjusted_mode->htotal, bpp,
- intel_dsi->lane_count) + 1);
+ intel_dsi->lane_count,
+ intel_dsi->burst_mode_ratio) + 1);
} else {
I915_WRITE(MIPI_HS_TX_TIMEOUT(pipe),
txbyteclkhs(adjusted_mode->vtotal *
adjusted_mode->htotal,
- bpp, intel_dsi->lane_count) + 1);
+ bpp, intel_dsi->lane_count,
+ intel_dsi->burst_mode_ratio) + 1);
}
I915_WRITE(MIPI_LP_RX_TIMEOUT(pipe), intel_dsi->lp_rx_timeout);
I915_WRITE(MIPI_TURN_AROUND_TIMEOUT(pipe), intel_dsi->turn_arnd_val);
diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
index fd51867..657eb5c 100644
--- a/drivers/gpu/drm/i915/intel_dsi.h
+++ b/drivers/gpu/drm/i915/intel_dsi.h
@@ -116,6 +116,8 @@ struct intel_dsi {
u16 clk_hs_to_lp_count;

u16 init_count;
+ u32 pclk;
+ u16 burst_mode_ratio;

/* all delays in ms */
u16 backlight_off_delay;
diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
index 47c7584..f6bdd44 100644
--- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
+++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
@@ -271,6 +271,8 @@ static bool generic_init(struct intel_dsi_device *dsi)
u32 ths_prepare_ns, tclk_trail_ns;
u32 tclk_prepare_clkzero, ths_prepare_hszero;
u32 lp_to_hs_switch, hs_to_lp_switch;
+ u32 pclk, computed_ddr;
+ u16 burst_mode_ratio;

DRM_DEBUG_KMS("\n");

@@ -284,8 +286,6 @@ static bool generic_init(struct intel_dsi_device *dsi)
else if (intel_dsi->pixel_format == VID_MODE_FORMAT_RGB565)
bits_per_pixel = 16;

- bitrate = (mode->clock * bits_per_pixel) / intel_dsi->lane_count;
-
intel_dsi->operation_mode = mipi_config->is_cmd_mode;
intel_dsi->video_mode_format = mipi_config->video_transfer_mode;
intel_dsi->escape_clk_div = mipi_config->byte_clk_sel;
@@ -297,6 +297,40 @@ static bool generic_init(struct intel_dsi_device *dsi)
intel_dsi->video_frmt_cfg_bits =
mipi_config->bta_enabled ? DISABLE_VIDEO_BTA : 0;

+ pclk = mode->clock;
+
+ /* Burst Mode Ratio
+ * Target ddr frequency from VBT / non burst ddr freq
+ * multiply by 100 to preserve remainder
+ */
+ if (intel_dsi->video_mode_format == VIDEO_MODE_BURST) {
+ if (mipi_config->target_burst_mode_freq) {
+ computed_ddr =
+ (pclk * bits_per_pixel) / intel_dsi->lane_count;
+
+ if (mipi_config->target_burst_mode_freq <
+ computed_ddr) {
+ DRM_ERROR("Burst mode freq is less than computed\n");
+ return false;
+ }
+
+ burst_mode_ratio = DIV_ROUND_UP(
+ mipi_config->target_burst_mode_freq * 100,
+ computed_ddr);
+
+ pclk = DIV_ROUND_UP(pclk * burst_mode_ratio, 100);
+ } else {
+ DRM_ERROR("Burst mode target is not set\n");
+ return false;
+ }
+ } else
+ burst_mode_ratio = 100;
+
+ intel_dsi->burst_mode_ratio = burst_mode_ratio;
+ intel_dsi->pclk = pclk;
+
+ bitrate = (pclk * bits_per_pixel) / intel_dsi->lane_count;
+
switch (intel_dsi->escape_clk_div) {
case 0:
tlpx_ns = 50;
diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c
index d8bb1ea..06fad93 100644
--- a/drivers/gpu/drm/i915/intel_dsi_pll.c
+++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
@@ -134,8 +134,7 @@ static u32 dsi_rr_formula(const struct drm_display_mode *mode,
#else

/* Get DSI clock from pixel clock */
-static u32 dsi_clk_from_pclk(const struct drm_display_mode *mode,
- int pixel_format, int lane_count)
+static u32 dsi_clk_from_pclk(u32 pclk, int pixel_format, int lane_count)
{
u32 dsi_clk_khz;
u32 bpp;
@@ -156,7 +155,7 @@ static u32 dsi_clk_from_pclk(const struct drm_display_mode *mode,

/* DSI data rate = pixel clock * bits per pixel / lane count
pixel clock is converted from KHz to Hz */
- dsi_clk_khz = DIV_ROUND_CLOSEST(mode->clock * bpp, lane_count);
+ dsi_clk_khz = DIV_ROUND_CLOSEST(pclk * bpp, lane_count);

return dsi_clk_khz;
}
@@ -228,14 +227,12 @@ static int dsi_calc_mnp(u32 dsi_clk, struct dsi_mnp *dsi_mnp)
static void vlv_configure_dsi_pll(struct intel_encoder *encoder)
{
struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
- struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
- const struct drm_display_mode *mode = &intel_crtc->config.adjusted_mode;
struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
int ret;
struct dsi_mnp dsi_mnp;
u32 dsi_clk;

- dsi_clk = dsi_clk_from_pclk(mode, intel_dsi->pixel_format,
+ dsi_clk = dsi_clk_from_pclk(intel_dsi->pclk, intel_dsi->pixel_format,
intel_dsi->lane_count);

ret = dsi_calc_mnp(dsi_clk, &dsi_mnp);
--
1.9.1