drm/i915: add FIFO watermark support for G4x

Turns out G4x needs to have sensible watermarks set, especially for
self-refresh enabled modes.  Add support for it.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Dirk Hohndel <hohndel@infradead.org>
Signed-off-by: Eric Anholt <eric@anholt.net>

2 files changed, 84 insertions, 8 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 78f336e0083..1687edf6879 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1799,17 +1799,29 @@
 #define   DSPARB_AEND_SHIFT     0
 
 #define DSPFW1                  0x70034
+#define   DSPFW_SR_SHIFT        23
+#define   DSPFW_CURSORB_SHIFT   16
+#define   DSPFW_PLANEB_SHIFT    8
 #define DSPFW2                  0x70038
+#define   DSPFW_CURSORA_MASK    0x00003f00
+#define   DSPFW_CURSORA_SHIFT   16
 #define DSPFW3                  0x7003c
+#define   DSPFW_HPLL_SR_EN      (1<<31)
+#define   DSPFW_CURSOR_SR_SHIFT 24
 #define   IGD_SELF_REFRESH_EN   (1<<30)
 
 /* FIFO watermark sizes etc */
+#define G4X_FIFO_LINE_SIZE      64
 #define I915_FIFO_LINE_SIZE     64
 #define I830_FIFO_LINE_SIZE     32
+
+#define G4X_FIFO_SIZE           127
 #define I945_FIFO_SIZE          127 /* 945 & 965 */
 #define I915_FIFO_SIZE          95
 #define I855GM_FIFO_SIZE        127 /* In cachelines */
 #define I830_FIFO_SIZE          95
+
+#define G4X_MAX_WM              0x3f
 #define I915_MAX_WM             0x3f
 
 #define IGD_DISPLAY_FIFO        512 /* in 64byte unit */
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e189fd6dedc..47d6ff05899 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2143,6 +2143,13 @@ static struct intel_watermark_params igd_cursor_hplloff_wm = {
         IGD_CURSOR_GUARD_WM,
         IGD_FIFO_LINE_SIZE
 };
+static struct intel_watermark_params g4x_wm_info = {
+        G4X_FIFO_SIZE,
+        G4X_MAX_WM,
+        G4X_MAX_WM,
+        2,
+        G4X_FIFO_LINE_SIZE,
+};
 static struct intel_watermark_params i945_wm_info = {
         I945_FIFO_SIZE,
         I915_MAX_WM,
@@ -2433,17 +2440,74 @@ static int i830_get_fifo_size(struct drm_device *dev, int plane)
         return size;
 }
 
-static void g4x_update_wm(struct drm_device *dev, int unused, int unused2,
-                          int unused3, int unused4)
+static void g4x_update_wm(struct drm_device *dev,  int planea_clock,
+                          int planeb_clock, int sr_hdisplay, int pixel_size)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
-        u32 fw_blc_self = I915_READ(FW_BLC_SELF);
+        int total_size, cacheline_size;
+        int planea_wm, planeb_wm, cursora_wm, cursorb_wm, cursor_sr;
+        struct intel_watermark_params planea_params, planeb_params;
+        unsigned long line_time_us;
+        int sr_clock, sr_entries = 0, entries_required;
 
-        if (i915_powersave)
-                fw_blc_self |= FW_BLC_SELF_EN;
-        else
-                fw_blc_self &= ~FW_BLC_SELF_EN;
-        I915_WRITE(FW_BLC_SELF, fw_blc_self);
+        /* Create copies of the base settings for each pipe */
+        planea_params = planeb_params = g4x_wm_info;
+
+        /* Grab a couple of global values before we overwrite them */
+        total_size = planea_params.fifo_size;
+        cacheline_size = planea_params.cacheline_size;
+
+        /*
+         * Note: we need to make sure we don't overflow for various clock &
+         * latency values.
+         * clocks go from a few thousand to several hundred thousand.
+         * latency is usually a few thousand
+         */
+        entries_required = ((planea_clock / 1000) * pixel_size * latency_ns) /
+                1000;
+        entries_required /= G4X_FIFO_LINE_SIZE;
+        planea_wm = entries_required + planea_params.guard_size;
+
+        entries_required = ((planeb_clock / 1000) * pixel_size * latency_ns) /
+                1000;
+        entries_required /= G4X_FIFO_LINE_SIZE;
+        planeb_wm = entries_required + planeb_params.guard_size;
+
+        cursora_wm = cursorb_wm = 16;
+        cursor_sr = 32;
+
+        DRM_DEBUG("FIFO watermarks - A: %d, B: %d\n", planea_wm, planeb_wm);
+
+        /* Calc sr entries for one plane configs */
+        if (sr_hdisplay && (!planea_clock || !planeb_clock)) {
+                /* self-refresh has much higher latency */
+                const static int sr_latency_ns = 12000;
+
+                sr_clock = planea_clock ? planea_clock : planeb_clock;
+                line_time_us = ((sr_hdisplay * 1000) / sr_clock);
+
+                /* Use ns/us then divide to preserve precision */
+                sr_entries = (((sr_latency_ns / line_time_us) + 1) *
+                              pixel_size * sr_hdisplay) / 1000;
+                sr_entries = roundup(sr_entries / cacheline_size, 1);
+                DRM_DEBUG("self-refresh entries: %d\n", sr_entries);
+                I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN);
+        }
+
+        DRM_DEBUG("Setting FIFO watermarks - A: %d, B: %d, SR %d\n",
+                  planea_wm, planeb_wm, sr_entries);
+
+        planea_wm &= 0x3f;
+        planeb_wm &= 0x3f;
+
+        I915_WRITE(DSPFW1, (sr_entries << DSPFW_SR_SHIFT) |
+                   (cursorb_wm << DSPFW_CURSORB_SHIFT) |
+                   (planeb_wm << DSPFW_PLANEB_SHIFT) | planea_wm);
+        I915_WRITE(DSPFW2, (I915_READ(DSPFW2) & DSPFW_CURSORA_MASK) |
+                   (cursora_wm << DSPFW_CURSORA_SHIFT));
+        /* HPLL off in SR has some issues on G4x... disable it */
+        I915_WRITE(DSPFW3, (I915_READ(DSPFW3) & ~DSPFW_HPLL_SR_EN) |
+                   (cursor_sr << DSPFW_CURSOR_SR_SHIFT));
 }
 
 static void i965_update_wm(struct drm_device *dev, int unused, int unused2,