drm/i915: Do not overflow the MMADDR write FIFO

Whilst the GT is powered down (rc6), writes to MMADDR are placed in a
FIFO by the System Agent. This is a limited resource, only 64 entries, of
which 20 are reserved for Display and PCH writes, and so we must take
care not to queue up too many writes. To avoid this, there is counter
which we can poll to ensure there are sufficient free entries in the
fifo.

"Issuing a write to a full FIFO is not supported; at worst it could
result in corruption or a system hang."

Reported-and-Tested-by: Matt Turner <mattst88@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34056
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 3601466c55027391c355fe1c11186913394fbf2d..4ff9b6cc973f031f363b8a25c669765793920951 100644 (file)
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -865,7 +865,7 @@ static int i915_cur_delayinfo(struct seq_file *m, void *unused)
                int max_freq;
 
                /* RPSTAT1 is in the GT power well */
-               __gen6_force_wake_get(dev_priv);
+               __gen6_gt_force_wake_get(dev_priv);
 
                seq_printf(m, "GT_PERF_STATUS: 0x%08x\n", gt_perf_status);
                seq_printf(m, "RPSTAT1: 0x%08x\n", I915_READ(GEN6_RPSTAT1));
@@ -888,7 +888,7 @@ static int i915_cur_delayinfo(struct seq_file *m, void *unused)
                seq_printf(m, "Max non-overclocked (RP0) frequency: %dMHz\n",
                           max_freq * 100);
 
-               __gen6_force_wake_put(dev_priv);
+               __gen6_gt_force_wake_put(dev_priv);
        } else {
                seq_printf(m, "no P-state info available\n");
        }

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 0ad533f06af97361a51666c7262eb96c4f218e71..37d672a116db6e90eca8cb105197e1e2298d695f 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -254,7 +254,7 @@ void intel_detect_pch (struct drm_device *dev)
        }
 }
 
-void __gen6_force_wake_get(struct drm_i915_private *dev_priv)
+void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
 {
        int count;
 
@@ -270,12 +270,22 @@ void __gen6_force_wake_get(struct drm_i915_private *dev_priv)
                udelay(10);
 }
 
-void __gen6_force_wake_put(struct drm_i915_private *dev_priv)
+void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv)
 {
        I915_WRITE_NOTRACE(FORCEWAKE, 0);
        POSTING_READ(FORCEWAKE);
 }
 
+void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv)
+{
+       int loop = 500;
+       u32 fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES);
+       while (fifo < 20 && loop--) {
+               udelay(10);
+               fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES);
+       }
+}
+
 static int i915_drm_freeze(struct drm_device *dev)
 {
        struct drm_i915_private *dev_priv = dev->dev_private;

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 65dfe81d0035bc9ced9636c1397373c6664e5e20..549c046b4ecc6afc62ab9da3accb83b2899029bc 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1353,22 +1353,32 @@ __i915_write(64, q)
  * must be set to prevent GT core from power down and stale values being
  * returned.
  */
-void __gen6_force_wake_get(struct drm_i915_private *dev_priv);
-void __gen6_force_wake_put (struct drm_i915_private *dev_priv);
-static inline u32 i915_safe_read(struct drm_i915_private *dev_priv, u32 reg)
+void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv);
+void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv);
+void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv);
+
+static inline u32 i915_gt_read(struct drm_i915_private *dev_priv, u32 reg)
 {
        u32 val;
 
        if (dev_priv->info->gen >= 6) {
-               __gen6_force_wake_get(dev_priv);
+               __gen6_gt_force_wake_get(dev_priv);
                val = I915_READ(reg);
-               __gen6_force_wake_put(dev_priv);
+               __gen6_gt_force_wake_put(dev_priv);
        } else
                val = I915_READ(reg);
 
        return val;
 }
 
+static inline void i915_gt_write(struct drm_i915_private *dev_priv,
+                               u32 reg, u32 val)
+{
+       if (dev_priv->info->gen >= 6)
+               __gen6_gt_wait_for_fifo(dev_priv);
+       I915_WRITE(reg, val);
+}
+
 static inline void
 i915_write(struct drm_i915_private *dev_priv, u32 reg, u64 val, int len)
 {

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 729d4233b763d2576c4ded20a1b5a330efe8a56c..3e6f486f4605b57af97797e8dae0d9e2eea35b3b 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3261,6 +3261,8 @@
 #define  FORCEWAKE                             0xA18C
 #define  FORCEWAKE_ACK                         0x130090
 
+#define  GT_FIFO_FREE_ENTRIES                  0x120008
+
 #define GEN6_RPNSWREQ                          0xA008
 #define   GEN6_TURBO_DISABLE                   (1<<31)
 #define   GEN6_FREQUENCY(x)                    ((x)<<25)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e79b25bbee6c49474db0fd54e702fd635805dccc..49fb54fd9a1879d2185b32bd1fb3597d82ee31a9 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1219,7 +1219,7 @@ static void sandybridge_blit_fbc_update(struct drm_device *dev)
        u32 blt_ecoskpd;
 
        /* Make sure blitter notifies FBC of writes */
-       __gen6_force_wake_get(dev_priv);
+       __gen6_gt_force_wake_get(dev_priv);
        blt_ecoskpd = I915_READ(GEN6_BLITTER_ECOSKPD);
        blt_ecoskpd |= GEN6_BLITTER_FBC_NOTIFY <<
                GEN6_BLITTER_LOCK_SHIFT;
@@ -1230,7 +1230,7 @@ static void sandybridge_blit_fbc_update(struct drm_device *dev)
                         GEN6_BLITTER_LOCK_SHIFT);
        I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
        POSTING_READ(GEN6_BLITTER_ECOSKPD);
-       __gen6_force_wake_put(dev_priv);
+       __gen6_gt_force_wake_put(dev_priv);
 }
 
 static void ironlake_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
@@ -6282,7 +6282,7 @@ void gen6_enable_rps(struct drm_i915_private *dev_priv)
         * userspace...
         */
        I915_WRITE(GEN6_RC_STATE, 0);
-       __gen6_force_wake_get(dev_priv);
+       __gen6_gt_force_wake_get(dev_priv);
 
        /* disable the counters and set deterministic thresholds */
        I915_WRITE(GEN6_RC_CONTROL, 0);
@@ -6380,7 +6380,7 @@ void gen6_enable_rps(struct drm_i915_private *dev_priv)
        /* enable all PM interrupts */
        I915_WRITE(GEN6_PMINTRMSK, 0);
 
-       __gen6_force_wake_put(dev_priv);
+       __gen6_gt_force_wake_put(dev_priv);
 }
 
 void intel_enable_clock_gating(struct drm_device *dev)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 6d6fde85a636248e373d9ef288450597f1ba6f91..34306865a5df936bad131c41eae47118146b1f52 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -14,22 +14,23 @@ struct  intel_hw_status_page {
        struct          drm_i915_gem_object *obj;
 };
 
-#define I915_RING_READ(reg) i915_safe_read(dev_priv, reg)
+#define I915_RING_READ(reg) i915_gt_read(dev_priv, reg)
+#define I915_RING_WRITE(reg, val) i915_gt_write(dev_priv, reg, val)
 
 #define I915_READ_TAIL(ring) I915_RING_READ(RING_TAIL((ring)->mmio_base))
-#define I915_WRITE_TAIL(ring, val) I915_WRITE(RING_TAIL((ring)->mmio_base), val)
+#define I915_WRITE_TAIL(ring, val) I915_RING_WRITE(RING_TAIL((ring)->mmio_base), val)
 
 #define I915_READ_START(ring) I915_RING_READ(RING_START((ring)->mmio_base))
-#define I915_WRITE_START(ring, val) I915_WRITE(RING_START((ring)->mmio_base), val)
+#define I915_WRITE_START(ring, val) I915_RING_WRITE(RING_START((ring)->mmio_base), val)
 
 #define I915_READ_HEAD(ring)  I915_RING_READ(RING_HEAD((ring)->mmio_base))
-#define I915_WRITE_HEAD(ring, val) I915_WRITE(RING_HEAD((ring)->mmio_base), val)
+#define I915_WRITE_HEAD(ring, val) I915_RING_WRITE(RING_HEAD((ring)->mmio_base), val)
 
 #define I915_READ_CTL(ring) I915_RING_READ(RING_CTL((ring)->mmio_base))
-#define I915_WRITE_CTL(ring, val) I915_WRITE(RING_CTL((ring)->mmio_base), val)
+#define I915_WRITE_CTL(ring, val) I915_RING_WRITE(RING_CTL((ring)->mmio_base), val)
 
-#define I915_WRITE_IMR(ring, val) I915_WRITE(RING_IMR((ring)->mmio_base), val)
 #define I915_READ_IMR(ring) I915_RING_READ(RING_IMR((ring)->mmio_base))
+#define I915_WRITE_IMR(ring, val) I915_RING_WRITE(RING_IMR((ring)->mmio_base), val)
 
 #define I915_READ_NOPID(ring) I915_RING_READ(RING_NOPID((ring)->mmio_base))
 #define I915_READ_SYNC_0(ring) I915_RING_READ(RING_SYNC_0((ring)->mmio_base))