drm/i915: Make all GPU resets atomic

In preparation for the next few commits, make resetting the GPU atomic.
Currently, we have prepared gen6+ for atomic resetting of individual
engines, but now there is a requirement to perform the whole device
level reset (just the register poking) from inside an atomic context.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190125132230.22221-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_reset.c b/drivers/gpu/drm/i915/i915_reset.c
index 342d9ee..2f84085 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reset.c
+++ b/drivers/gpu/drm/i915/i915_reset.c
@@ -12,6 +12,8 @@
 
 #include "intel_guc.h"
 
+#define RESET_MAX_RETRIES 3
+
 static void engine_skip_context(struct i915_request *rq)
 {
        struct intel_engine_cs *engine = rq->engine;
@@ -144,14 +146,14 @@ static int i915_do_reset(struct drm_i915_private *i915,
 
        /* Assert reset for at least 20 usec, and wait for acknowledgement. */
        pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
-       usleep_range(50, 200);
-       err = wait_for(i915_in_reset(pdev), 500);
+       udelay(50);
+       err = wait_for_atomic(i915_in_reset(pdev), 50);
 
        /* Clear the reset request. */
        pci_write_config_byte(pdev, I915_GDRST, 0);
-       usleep_range(50, 200);
+       udelay(50);
        if (!err)
-               err = wait_for(!i915_in_reset(pdev), 500);
+               err = wait_for_atomic(!i915_in_reset(pdev), 50);
 
        return err;
 }
@@ -171,7 +173,7 @@ static int g33_do_reset(struct drm_i915_private *i915,
        struct pci_dev *pdev = i915->drm.pdev;
 
        pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
-       return wait_for(g4x_reset_complete(pdev), 500);
+       return wait_for_atomic(g4x_reset_complete(pdev), 50);
 }
 
 static int g4x_do_reset(struct drm_i915_private *dev_priv,
@@ -182,13 +184,13 @@ static int g4x_do_reset(struct drm_i915_private *dev_priv,
        int ret;
 
        /* WaVcpClkGateDisableForMediaReset:ctg,elk */
-       I915_WRITE(VDECCLK_GATE_D,
-                  I915_READ(VDECCLK_GATE_D) | VCP_UNIT_CLOCK_GATE_DISABLE);
-       POSTING_READ(VDECCLK_GATE_D);
+       I915_WRITE_FW(VDECCLK_GATE_D,
+                     I915_READ(VDECCLK_GATE_D) | VCP_UNIT_CLOCK_GATE_DISABLE);
+       POSTING_READ_FW(VDECCLK_GATE_D);
 
        pci_write_config_byte(pdev, I915_GDRST,
                              GRDOM_MEDIA | GRDOM_RESET_ENABLE);
-       ret =  wait_for(g4x_reset_complete(pdev), 500);
+       ret =  wait_for_atomic(g4x_reset_complete(pdev), 50);
        if (ret) {
                DRM_DEBUG_DRIVER("Wait for media reset failed\n");
                goto out;
@@ -196,7 +198,7 @@ static int g4x_do_reset(struct drm_i915_private *dev_priv,
 
        pci_write_config_byte(pdev, I915_GDRST,
                              GRDOM_RENDER | GRDOM_RESET_ENABLE);
-       ret =  wait_for(g4x_reset_complete(pdev), 500);
+       ret =  wait_for_atomic(g4x_reset_complete(pdev), 50);
        if (ret) {
                DRM_DEBUG_DRIVER("Wait for render reset failed\n");
                goto out;
@@ -205,9 +207,9 @@ static int g4x_do_reset(struct drm_i915_private *dev_priv,
 out:
        pci_write_config_byte(pdev, I915_GDRST, 0);
 
-       I915_WRITE(VDECCLK_GATE_D,
-                  I915_READ(VDECCLK_GATE_D) & ~VCP_UNIT_CLOCK_GATE_DISABLE);
-       POSTING_READ(VDECCLK_GATE_D);
+       I915_WRITE_FW(VDECCLK_GATE_D,
+                     I915_READ(VDECCLK_GATE_D) & ~VCP_UNIT_CLOCK_GATE_DISABLE);
+       POSTING_READ_FW(VDECCLK_GATE_D);
 
        return ret;
 }
@@ -218,27 +220,29 @@ static int ironlake_do_reset(struct drm_i915_private *dev_priv,
 {
        int ret;
 
-       I915_WRITE(ILK_GDSR, ILK_GRDOM_RENDER | ILK_GRDOM_RESET_ENABLE);
-       ret = intel_wait_for_register(dev_priv,
-                                     ILK_GDSR, ILK_GRDOM_RESET_ENABLE, 0,
-                                     500);
+       I915_WRITE_FW(ILK_GDSR, ILK_GRDOM_RENDER | ILK_GRDOM_RESET_ENABLE);
+       ret = __intel_wait_for_register_fw(dev_priv, ILK_GDSR,
+                                          ILK_GRDOM_RESET_ENABLE, 0,
+                                          5000, 0,
+                                          NULL);
        if (ret) {
                DRM_DEBUG_DRIVER("Wait for render reset failed\n");
                goto out;
        }
 
-       I915_WRITE(ILK_GDSR, ILK_GRDOM_MEDIA | ILK_GRDOM_RESET_ENABLE);
-       ret = intel_wait_for_register(dev_priv,
-                                     ILK_GDSR, ILK_GRDOM_RESET_ENABLE, 0,
-                                     500);
+       I915_WRITE_FW(ILK_GDSR, ILK_GRDOM_MEDIA | ILK_GRDOM_RESET_ENABLE);
+       ret = __intel_wait_for_register_fw(dev_priv, ILK_GDSR,
+                                          ILK_GRDOM_RESET_ENABLE, 0,
+                                          5000, 0,
+                                          NULL);
        if (ret) {
                DRM_DEBUG_DRIVER("Wait for media reset failed\n");
                goto out;
        }
 
 out:
-       I915_WRITE(ILK_GDSR, 0);
-       POSTING_READ(ILK_GDSR);
+       I915_WRITE_FW(ILK_GDSR, 0);
+       POSTING_READ_FW(ILK_GDSR);
        return ret;
 }
 
@@ -527,32 +531,21 @@ static reset_func intel_get_gpu_reset(struct drm_i915_private *i915)
 
 int intel_gpu_reset(struct drm_i915_private *i915, unsigned int engine_mask)
 {
-       reset_func reset = intel_get_gpu_reset(i915);
+       const int retries = engine_mask == ALL_ENGINES ? RESET_MAX_RETRIES : 1;
+       reset_func reset;
+       int ret = -ETIMEDOUT;
        int retry;
-       int ret;
 
-       /*
-        * We want to perform per-engine reset from atomic context (e.g.
-        * softirq), which imposes the constraint that we cannot sleep.
-        * However, experience suggests that spending a bit of time waiting
-        * for a reset helps in various cases, so for a full-device reset
-        * we apply the opposite rule and wait if we want to. As we should
-        * always follow up a failed per-engine reset with a full device reset,
-        * being a little faster, stricter and more error prone for the
-        * atomic case seems an acceptable compromise.
-        *
-        * Unfortunately this leads to a bimodal routine, when the goal was
-        * to have a single reset function that worked for resetting any
-        * number of engines simultaneously.
-        */
-       might_sleep_if(engine_mask == ALL_ENGINES);
+       reset = intel_get_gpu_reset(i915);
+       if (!reset)
+               return -ENODEV;
 
        /*
         * If the power well sleeps during the reset, the reset
         * request may be dropped and never completes (causing -EIO).
         */
        intel_uncore_forcewake_get(i915, FORCEWAKE_ALL);
-       for (retry = 0; retry < 3; retry++) {
+       for (retry = 0; ret == -ETIMEDOUT && retry < retries; retry++) {
                /*
                 * We stop engines, otherwise we might get failed reset and a
                 * dead gpu (on elk). Also as modern gpu as kbl can suffer
@@ -569,15 +562,10 @@ int intel_gpu_reset(struct drm_i915_private *i915, unsigned int engine_mask)
                 */
                i915_stop_engines(i915, engine_mask);
 
-               ret = -ENODEV;
-               if (reset) {
-                       GEM_TRACE("engine_mask=%x\n", engine_mask);
-                       ret = reset(i915, engine_mask, retry);
-               }
-               if (ret != -ETIMEDOUT || engine_mask != ALL_ENGINES)
-                       break;
-
-               cond_resched();
+               GEM_TRACE("engine_mask=%x\n", engine_mask);
+               preempt_disable();
+               ret = reset(i915, engine_mask, retry);
+               preempt_enable();
        }
        intel_uncore_forcewake_put(i915, FORCEWAKE_ALL);
 
@@ -1014,7 +1002,7 @@ void i915_reset(struct drm_i915_private *i915,
                goto error;
        }
 
-       for (i = 0; i < 3; i++) {
+       for (i = 0; i < RESET_MAX_RETRIES; i++) {
                ret = intel_gpu_reset(i915, ALL_ENGINES);
                if (ret == 0)
                        break;