drm/tegra: sor - Do not hardcode number of blank symbols
The number of HBLANK and VBLANK symbols can be computed at runtime so
that they can be set appropriately depending on the video mode and DP
link.
These values are used by the packet generation logic to determine how
many audio samples can be transferred during the blanking intervals.
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/sor.c b/drivers/gpu/drm/tegra/sor.c
index 4b55490..ff025aa 100644
--- a/drivers/gpu/drm/tegra/sor.c
+++ b/drivers/gpu/drm/tegra/sor.c
@@ -48,6 +48,9 @@
u32 tu_size;
u32 active_frac;
u32 watermark;
+
+ u32 hblank_symbols;
+ u32 vblank_symbols;
};
static inline struct tegra_sor *
@@ -393,8 +396,8 @@
{
const u64 f = 100000, link_rate = link->rate * 1000;
const u64 pclk = mode->clock * 1000;
+ u64 input, output, watermark, num;
struct tegra_sor_params params;
- u64 input, output, watermark;
u32 num_syms_per_line;
unsigned int i;
@@ -458,6 +461,23 @@
config->watermark);
}
+ /* compute the number of symbols per horizontal blanking interval */
+ num = ((mode->htotal - mode->hdisplay) - 7) * link_rate;
+ config->hblank_symbols = div_u64(num, pclk);
+
+ if (link->capabilities & DP_LINK_CAP_ENHANCED_FRAMING)
+ config->hblank_symbols -= 3;
+
+ config->hblank_symbols -= 12 / link->num_lanes;
+
+ /* compute the number of symbols per vertical blanking interval */
+ num = (mode->hdisplay - 25) * link_rate;
+ config->vblank_symbols = div_u64(num, pclk);
+ config->vblank_symbols -= 36 / link->num_lanes + 4;
+
+ dev_dbg(sor->dev, "blank symbols: H:%u V:%u\n", config->hblank_symbols,
+ config->vblank_symbols);
+
return 0;
}
@@ -684,12 +704,12 @@
value = tegra_sor_readl(sor, SOR_DP_AUDIO_HBLANK_SYMBOLS);
value &= ~SOR_DP_AUDIO_HBLANK_SYMBOLS_MASK;
- value |= 137; /* XXX: don't hardcode? */
+ value |= config.hblank_symbols & 0xffff;
tegra_sor_writel(sor, value, SOR_DP_AUDIO_HBLANK_SYMBOLS);
value = tegra_sor_readl(sor, SOR_DP_AUDIO_VBLANK_SYMBOLS);
value &= ~SOR_DP_AUDIO_VBLANK_SYMBOLS_MASK;
- value |= 2368; /* XXX: don't hardcode? */
+ value |= config.vblank_symbols & 0xffff;
tegra_sor_writel(sor, value, SOR_DP_AUDIO_VBLANK_SYMBOLS);
/* enable pad calibration logic */