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path: root/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
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Diffstat (limited to 'drivers/gpu/drm/msm/adreno/a5xx_preempt.c')
-rw-r--r--drivers/gpu/drm/msm/adreno/a5xx_preempt.c305
1 files changed, 305 insertions, 0 deletions
diff --git a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
new file mode 100644
index 000000000000..40f4840ef98e
--- /dev/null
+++ b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
@@ -0,0 +1,305 @@
+/* Copyright (c) 2017 The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include "msm_gem.h"
+#include "a5xx_gpu.h"
+
+/*
+ * Try to transition the preemption state from old to new. Return
+ * true on success or false if the original state wasn't 'old'
+ */
+static inline bool try_preempt_state(struct a5xx_gpu *a5xx_gpu,
+ enum preempt_state old, enum preempt_state new)
+{
+ enum preempt_state cur = atomic_cmpxchg(&a5xx_gpu->preempt_state,
+ old, new);
+
+ return (cur == old);
+}
+
+/*
+ * Force the preemption state to the specified state. This is used in cases
+ * where the current state is known and won't change
+ */
+static inline void set_preempt_state(struct a5xx_gpu *gpu,
+ enum preempt_state new)
+{
+ /*
+ * preempt_state may be read by other cores trying to trigger a
+ * preemption or in the interrupt handler so barriers are needed
+ * before...
+ */
+ smp_mb__before_atomic();
+ atomic_set(&gpu->preempt_state, new);
+ /* ... and after*/
+ smp_mb__after_atomic();
+}
+
+/* Write the most recent wptr for the given ring into the hardware */
+static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
+{
+ unsigned long flags;
+ uint32_t wptr;
+
+ if (!ring)
+ return;
+
+ spin_lock_irqsave(&ring->lock, flags);
+ wptr = get_wptr(ring);
+ spin_unlock_irqrestore(&ring->lock, flags);
+
+ gpu_write(gpu, REG_A5XX_CP_RB_WPTR, wptr);
+}
+
+/* Return the highest priority ringbuffer with something in it */
+static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
+{
+ unsigned long flags;
+ int i;
+
+ for (i = 0; i < gpu->nr_rings; i++) {
+ bool empty;
+ struct msm_ringbuffer *ring = gpu->rb[i];
+
+ spin_lock_irqsave(&ring->lock, flags);
+ empty = (get_wptr(ring) == ring->memptrs->rptr);
+ spin_unlock_irqrestore(&ring->lock, flags);
+
+ if (!empty)
+ return ring;
+ }
+
+ return NULL;
+}
+
+static void a5xx_preempt_timer(unsigned long data)
+{
+ struct a5xx_gpu *a5xx_gpu = (struct a5xx_gpu *) data;
+ struct msm_gpu *gpu = &a5xx_gpu->base.base;
+ struct drm_device *dev = gpu->dev;
+ struct msm_drm_private *priv = dev->dev_private;
+
+ if (!try_preempt_state(a5xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
+ return;
+
+ dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
+ queue_work(priv->wq, &gpu->recover_work);
+}
+
+/* Try to trigger a preemption switch */
+void a5xx_preempt_trigger(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a5xx_gpu *a5xx_gpu = to_a5xx_gpu(adreno_gpu);
+ unsigned long flags;
+ struct msm_ringbuffer *ring;
+
+ if (gpu->nr_rings == 1)
+ return;
+
+ /*
+ * Try to start preemption by moving from NONE to START. If
+ * unsuccessful, a preemption is already in flight
+ */
+ if (!try_preempt_state(a5xx_gpu, PREEMPT_NONE, PREEMPT_START))
+ return;
+
+ /* Get the next ring to preempt to */
+ ring = get_next_ring(gpu);
+
+ /*
+ * If no ring is populated or the highest priority ring is the current
+ * one do nothing except to update the wptr to the latest and greatest
+ */
+ if (!ring || (a5xx_gpu->cur_ring == ring)) {
+ /*
+ * Its possible that while a preemption request is in progress
+ * from an irq context, a user context trying to submit might
+ * fail to update the write pointer, because it determines
+ * that the preempt state is not PREEMPT_NONE.
+ *
+ * Close the race by introducing an intermediate
+ * state PREEMPT_ABORT to let the submit path
+ * know that the ringbuffer is not going to change
+ * and can safely update the write pointer.
+ */
+
+ set_preempt_state(a5xx_gpu, PREEMPT_ABORT);
+ update_wptr(gpu, a5xx_gpu->cur_ring);
+ set_preempt_state(a5xx_gpu, PREEMPT_NONE);
+ return;
+ }
+
+ /* Make sure the wptr doesn't update while we're in motion */
+ spin_lock_irqsave(&ring->lock, flags);
+ a5xx_gpu->preempt[ring->id]->wptr = get_wptr(ring);
+ spin_unlock_irqrestore(&ring->lock, flags);
+
+ /* Set the address of the incoming preemption record */
+ gpu_write64(gpu, REG_A5XX_CP_CONTEXT_SWITCH_RESTORE_ADDR_LO,
+ REG_A5XX_CP_CONTEXT_SWITCH_RESTORE_ADDR_HI,
+ a5xx_gpu->preempt_iova[ring->id]);
+
+ a5xx_gpu->next_ring = ring;
+
+ /* Start a timer to catch a stuck preemption */
+ mod_timer(&a5xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
+
+ /* Set the preemption state to triggered */
+ set_preempt_state(a5xx_gpu, PREEMPT_TRIGGERED);
+
+ /* Make sure everything is written before hitting the button */
+ wmb();
+
+ /* And actually start the preemption */
+ gpu_write(gpu, REG_A5XX_CP_CONTEXT_SWITCH_CNTL, 1);
+}
+
+void a5xx_preempt_irq(struct msm_gpu *gpu)
+{
+ uint32_t status;
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a5xx_gpu *a5xx_gpu = to_a5xx_gpu(adreno_gpu);
+ struct drm_device *dev = gpu->dev;
+ struct msm_drm_private *priv = dev->dev_private;
+
+ if (!try_preempt_state(a5xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
+ return;
+
+ /* Delete the preemption watchdog timer */
+ del_timer(&a5xx_gpu->preempt_timer);
+
+ /*
+ * The hardware should be setting CP_CONTEXT_SWITCH_CNTL to zero before
+ * firing the interrupt, but there is a non zero chance of a hardware
+ * condition or a software race that could set it again before we have a
+ * chance to finish. If that happens, log and go for recovery
+ */
+ status = gpu_read(gpu, REG_A5XX_CP_CONTEXT_SWITCH_CNTL);
+ if (unlikely(status)) {
+ set_preempt_state(a5xx_gpu, PREEMPT_FAULTED);
+ dev_err(dev->dev, "%s: Preemption failed to complete\n",
+ gpu->name);
+ queue_work(priv->wq, &gpu->recover_work);
+ return;
+ }
+
+ a5xx_gpu->cur_ring = a5xx_gpu->next_ring;
+ a5xx_gpu->next_ring = NULL;
+
+ update_wptr(gpu, a5xx_gpu->cur_ring);
+
+ set_preempt_state(a5xx_gpu, PREEMPT_NONE);
+}
+
+void a5xx_preempt_hw_init(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a5xx_gpu *a5xx_gpu = to_a5xx_gpu(adreno_gpu);
+ int i;
+
+ for (i = 0; i < gpu->nr_rings; i++) {
+ a5xx_gpu->preempt[i]->wptr = 0;
+ a5xx_gpu->preempt[i]->rptr = 0;
+ a5xx_gpu->preempt[i]->rbase = gpu->rb[i]->iova;
+ }
+
+ /* Write a 0 to signal that we aren't switching pagetables */
+ gpu_write64(gpu, REG_A5XX_CP_CONTEXT_SWITCH_SMMU_INFO_LO,
+ REG_A5XX_CP_CONTEXT_SWITCH_SMMU_INFO_HI, 0);
+
+ /* Reset the preemption state */
+ set_preempt_state(a5xx_gpu, PREEMPT_NONE);
+
+ /* Always come up on rb 0 */
+ a5xx_gpu->cur_ring = gpu->rb[0];
+}
+
+static int preempt_init_ring(struct a5xx_gpu *a5xx_gpu,
+ struct msm_ringbuffer *ring)
+{
+ struct adreno_gpu *adreno_gpu = &a5xx_gpu->base;
+ struct msm_gpu *gpu = &adreno_gpu->base;
+ struct a5xx_preempt_record *ptr;
+ struct drm_gem_object *bo = NULL;
+ u64 iova = 0;
+
+ ptr = msm_gem_kernel_new(gpu->dev,
+ A5XX_PREEMPT_RECORD_SIZE + A5XX_PREEMPT_COUNTER_SIZE,
+ MSM_BO_UNCACHED, gpu->aspace, &bo, &iova);
+
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+
+ a5xx_gpu->preempt_bo[ring->id] = bo;
+ a5xx_gpu->preempt_iova[ring->id] = iova;
+ a5xx_gpu->preempt[ring->id] = ptr;
+
+ /* Set up the defaults on the preemption record */
+
+ ptr->magic = A5XX_PREEMPT_RECORD_MAGIC;
+ ptr->info = 0;
+ ptr->data = 0;
+ ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
+ ptr->rptr_addr = rbmemptr(ring, rptr);
+ ptr->counter = iova + A5XX_PREEMPT_RECORD_SIZE;
+
+ return 0;
+}
+
+void a5xx_preempt_fini(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a5xx_gpu *a5xx_gpu = to_a5xx_gpu(adreno_gpu);
+ int i;
+
+ for (i = 0; i < gpu->nr_rings; i++) {
+ if (!a5xx_gpu->preempt_bo[i])
+ continue;
+
+ msm_gem_put_vaddr(a5xx_gpu->preempt_bo[i]);
+
+ if (a5xx_gpu->preempt_iova[i])
+ msm_gem_put_iova(a5xx_gpu->preempt_bo[i], gpu->aspace);
+
+ drm_gem_object_unreference(a5xx_gpu->preempt_bo[i]);
+ a5xx_gpu->preempt_bo[i] = NULL;
+ }
+}
+
+void a5xx_preempt_init(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a5xx_gpu *a5xx_gpu = to_a5xx_gpu(adreno_gpu);
+ int i;
+
+ /* No preemption if we only have one ring */
+ if (gpu->nr_rings <= 1)
+ return;
+
+ for (i = 0; i < gpu->nr_rings; i++) {
+ if (preempt_init_ring(a5xx_gpu, gpu->rb[i])) {
+ /*
+ * On any failure our adventure is over. Clean up and
+ * set nr_rings to 1 to force preemption off
+ */
+ a5xx_preempt_fini(gpu);
+ gpu->nr_rings = 1;
+
+ return;
+ }
+ }
+
+ setup_timer(&a5xx_gpu->preempt_timer, a5xx_preempt_timer,
+ (unsigned long) a5xx_gpu);
+}