1 files changed, 457 insertions, 0 deletions

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
new file mode 100644
index 000000000000..3b17fd2dba89
--- /dev/null
+++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
@@ -0,0 +1,457 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */
+/* Copyright (c) 2023 Collabora, Ltd. */
+/* Copyright (c) 2024 Valve Corporation */
+
+#include "msm_gem.h"
+#include "a6xx_gpu.h"
+#include "a6xx_gmu.xml.h"
+#include "msm_mmu.h"
+#include "msm_gpu_trace.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 a6xx_gpu *a6xx_gpu,
+		enum a6xx_preempt_state old, enum a6xx_preempt_state new)
+{
+	enum a6xx_preempt_state cur = atomic_cmpxchg(&a6xx_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 a6xx_gpu *gpu,
+		enum a6xx_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;
+
+	spin_lock_irqsave(&ring->preempt_lock, flags);
+
+	if (ring->restore_wptr) {
+		wptr = get_wptr(ring);
+
+		gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
+
+		ring->restore_wptr = false;
+	}
+
+	spin_unlock_irqrestore(&ring->preempt_lock, flags);
+}
+
+/* Return the highest priority ringbuffer with something in it */
+static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_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->preempt_lock, flags);
+		empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
+		if (!empty && ring == a6xx_gpu->cur_ring)
+			empty = ring->memptrs->fence == a6xx_gpu->last_seqno[i];
+		spin_unlock_irqrestore(&ring->preempt_lock, flags);
+
+		if (!empty)
+			return ring;
+	}
+
+	return NULL;
+}
+
+static void a6xx_preempt_timer(struct timer_list *t)
+{
+	struct a6xx_gpu *a6xx_gpu = timer_container_of(a6xx_gpu, t,
+						       preempt_timer);
+	struct msm_gpu *gpu = &a6xx_gpu->base.base;
+	struct drm_device *dev = gpu->dev;
+
+	if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
+		return;
+
+	dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
+	kthread_queue_work(gpu->worker, &gpu->recover_work);
+}
+
+static void preempt_prepare_postamble(struct a6xx_gpu *a6xx_gpu)
+{
+	u32 *postamble = a6xx_gpu->preempt_postamble_ptr;
+	u32 count = 0;
+
+	postamble[count++] = PKT7(CP_REG_RMW, 3);
+	postamble[count++] = REG_A6XX_RBBM_PERFCTR_SRAM_INIT_CMD;
+	postamble[count++] = 0;
+	postamble[count++] = 1;
+
+	postamble[count++] = PKT7(CP_WAIT_REG_MEM, 6);
+	postamble[count++] = CP_WAIT_REG_MEM_0_FUNCTION(WRITE_EQ);
+	postamble[count++] = CP_WAIT_REG_MEM_1_POLL_ADDR_LO(
+				REG_A6XX_RBBM_PERFCTR_SRAM_INIT_STATUS);
+	postamble[count++] = CP_WAIT_REG_MEM_2_POLL_ADDR_HI(0);
+	postamble[count++] = CP_WAIT_REG_MEM_3_REF(0x1);
+	postamble[count++] = CP_WAIT_REG_MEM_4_MASK(0x1);
+	postamble[count++] = CP_WAIT_REG_MEM_5_DELAY_LOOP_CYCLES(0);
+
+	a6xx_gpu->preempt_postamble_len = count;
+
+	a6xx_gpu->postamble_enabled = true;
+}
+
+static void preempt_disable_postamble(struct a6xx_gpu *a6xx_gpu)
+{
+	u32 *postamble = a6xx_gpu->preempt_postamble_ptr;
+
+	/*
+	 * Disable the postamble by replacing the first packet header with a NOP
+	 * that covers the whole buffer.
+	 */
+	*postamble = PKT7(CP_NOP, (a6xx_gpu->preempt_postamble_len - 1));
+
+	a6xx_gpu->postamble_enabled = false;
+}
+
+void a6xx_preempt_irq(struct msm_gpu *gpu)
+{
+	uint32_t status;
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	struct drm_device *dev = gpu->dev;
+
+	if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
+		return;
+
+	/* Delete the preemption watchdog timer */
+	timer_delete(&a6xx_gpu->preempt_timer);
+
+	/*
+	 * The hardware should be setting the stop bit of 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_A6XX_CP_CONTEXT_SWITCH_CNTL);
+	if (unlikely(status & A6XX_CP_CONTEXT_SWITCH_CNTL_STOP)) {
+		DRM_DEV_ERROR(&gpu->pdev->dev,
+					  "!!!!!!!!!!!!!!!! preemption faulted !!!!!!!!!!!!!! irq\n");
+		set_preempt_state(a6xx_gpu, PREEMPT_FAULTED);
+		dev_err(dev->dev, "%s: Preemption failed to complete\n",
+			gpu->name);
+		kthread_queue_work(gpu->worker, &gpu->recover_work);
+		return;
+	}
+
+	a6xx_gpu->cur_ring = a6xx_gpu->next_ring;
+	a6xx_gpu->next_ring = NULL;
+
+	set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
+
+	update_wptr(gpu, a6xx_gpu->cur_ring);
+
+	set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+
+	trace_msm_gpu_preemption_irq(a6xx_gpu->cur_ring->id);
+
+	/*
+	 * Retrigger preemption to avoid a deadlock that might occur when preemption
+	 * is skipped due to it being already in flight when requested.
+	 */
+	a6xx_preempt_trigger(gpu);
+}
+
+void a6xx_preempt_hw_init(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_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++) {
+		struct a6xx_preempt_record *record_ptr = a6xx_gpu->preempt[i];
+
+		record_ptr->wptr = 0;
+		record_ptr->rptr = 0;
+		record_ptr->rptr_addr = shadowptr(a6xx_gpu, gpu->rb[i]);
+		record_ptr->info = 0;
+		record_ptr->data = 0;
+		record_ptr->rbase = gpu->rb[i]->iova;
+	}
+
+	/* Write a 0 to signal that we aren't switching pagetables */
+	gpu_write64(gpu, REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO, 0);
+
+	/* Enable the GMEM save/restore feature for preemption */
+	gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);
+
+	/* Reset the preemption state */
+	set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+
+	spin_lock_init(&a6xx_gpu->eval_lock);
+
+	/* Always come up on rb 0 */
+	a6xx_gpu->cur_ring = gpu->rb[0];
+}
+
+void a6xx_preempt_trigger(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	unsigned long flags;
+	struct msm_ringbuffer *ring;
+	unsigned int cntl;
+	bool sysprof;
+
+	if (gpu->nr_rings == 1)
+		return;
+
+	/*
+	 * Lock to make sure another thread attempting preemption doesn't skip it
+	 * while we are still evaluating the next ring. This makes sure the other
+	 * thread does start preemption if we abort it and avoids a soft lock.
+	 */
+	spin_lock_irqsave(&a6xx_gpu->eval_lock, flags);
+
+	/*
+	 * Try to start preemption by moving from NONE to START. If
+	 * unsuccessful, a preemption is already in flight
+	 */
+	if (!try_preempt_state(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) {
+		spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
+		return;
+	}
+
+	cntl = A6XX_CP_CONTEXT_SWITCH_CNTL_LEVEL(a6xx_gpu->preempt_level);
+
+	if (a6xx_gpu->skip_save_restore)
+		cntl |= A6XX_CP_CONTEXT_SWITCH_CNTL_SKIP_SAVE_RESTORE;
+
+	if (a6xx_gpu->uses_gmem)
+		cntl |= A6XX_CP_CONTEXT_SWITCH_CNTL_USES_GMEM;
+
+	cntl |= A6XX_CP_CONTEXT_SWITCH_CNTL_STOP;
+
+	/* 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 || (a6xx_gpu->cur_ring == ring)) {
+		set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
+		update_wptr(gpu, a6xx_gpu->cur_ring);
+		set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+		spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
+		return;
+	}
+
+	spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
+
+	spin_lock_irqsave(&ring->preempt_lock, flags);
+
+	struct a7xx_cp_smmu_info *smmu_info_ptr =
+		a6xx_gpu->preempt_smmu[ring->id];
+	struct a6xx_preempt_record *record_ptr = a6xx_gpu->preempt[ring->id];
+	u64 ttbr0 = ring->memptrs->ttbr0;
+	u32 context_idr = ring->memptrs->context_idr;
+
+	smmu_info_ptr->ttbr0 = ttbr0;
+	smmu_info_ptr->context_idr = context_idr;
+	record_ptr->wptr = get_wptr(ring);
+
+	/*
+	 * The GPU will write the wptr we set above when we preempt. Reset
+	 * restore_wptr to make sure that we don't write WPTR to the same
+	 * thing twice. It's still possible subsequent submissions will update
+	 * wptr again, in which case they will set the flag to true. This has
+	 * to be protected by the lock for setting the flag and updating wptr
+	 * to be atomic.
+	 */
+	ring->restore_wptr = false;
+
+	trace_msm_gpu_preemption_trigger(a6xx_gpu->cur_ring->id, ring->id);
+
+	spin_unlock_irqrestore(&ring->preempt_lock, flags);
+
+	gpu_write64(gpu,
+		REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO,
+		a6xx_gpu->preempt_smmu_iova[ring->id]);
+
+	gpu_write64(gpu,
+		REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
+		a6xx_gpu->preempt_iova[ring->id]);
+
+	a6xx_gpu->next_ring = ring;
+
+	/* Start a timer to catch a stuck preemption */
+	mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
+
+	/* Enable or disable postamble as needed */
+	sysprof = refcount_read(&a6xx_gpu->base.base.sysprof_active) > 1;
+
+	if (!sysprof && !a6xx_gpu->postamble_enabled)
+		preempt_prepare_postamble(a6xx_gpu);
+
+	if (sysprof && a6xx_gpu->postamble_enabled)
+		preempt_disable_postamble(a6xx_gpu);
+
+	/* Set the preemption state to triggered */
+	set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED);
+
+	/* Trigger the preemption */
+	gpu_write(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl);
+}
+
+static int preempt_init_ring(struct a6xx_gpu *a6xx_gpu,
+		struct msm_ringbuffer *ring)
+{
+	struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
+	struct msm_gpu *gpu = &adreno_gpu->base;
+	struct drm_gem_object *bo = NULL;
+	phys_addr_t ttbr;
+	u64 iova = 0;
+	void *ptr;
+	int asid;
+
+	ptr = msm_gem_kernel_new(gpu->dev,
+		PREEMPT_RECORD_SIZE(adreno_gpu),
+		MSM_BO_WC | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
+
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+
+	memset(ptr, 0, PREEMPT_RECORD_SIZE(adreno_gpu));
+
+	msm_gem_object_set_name(bo, "preempt_record ring%d", ring->id);
+
+	a6xx_gpu->preempt_bo[ring->id] = bo;
+	a6xx_gpu->preempt_iova[ring->id] = iova;
+	a6xx_gpu->preempt[ring->id] = ptr;
+
+	struct a6xx_preempt_record *record_ptr = ptr;
+
+	ptr = msm_gem_kernel_new(gpu->dev,
+		PREEMPT_SMMU_INFO_SIZE,
+		MSM_BO_WC | MSM_BO_MAP_PRIV | MSM_BO_GPU_READONLY,
+		gpu->aspace, &bo, &iova);
+
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+
+	memset(ptr, 0, PREEMPT_SMMU_INFO_SIZE);
+
+	msm_gem_object_set_name(bo, "preempt_smmu_info ring%d", ring->id);
+
+	a6xx_gpu->preempt_smmu_bo[ring->id] = bo;
+	a6xx_gpu->preempt_smmu_iova[ring->id] = iova;
+	a6xx_gpu->preempt_smmu[ring->id] = ptr;
+
+	struct a7xx_cp_smmu_info *smmu_info_ptr = ptr;
+
+	msm_iommu_pagetable_params(gpu->aspace->mmu, &ttbr, &asid);
+
+	smmu_info_ptr->magic = GEN7_CP_SMMU_INFO_MAGIC;
+	smmu_info_ptr->ttbr0 = ttbr;
+	smmu_info_ptr->asid = 0xdecafbad;
+	smmu_info_ptr->context_idr = 0;
+
+	/* Set up the defaults on the preemption record */
+	record_ptr->magic = A6XX_PREEMPT_RECORD_MAGIC;
+	record_ptr->info = 0;
+	record_ptr->data = 0;
+	record_ptr->rptr = 0;
+	record_ptr->wptr = 0;
+	record_ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
+	record_ptr->rbase = ring->iova;
+	record_ptr->counter = 0;
+	record_ptr->bv_rptr_addr = rbmemptr(ring, bv_rptr);
+
+	return 0;
+}
+
+void a6xx_preempt_fini(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	int i;
+
+	for (i = 0; i < gpu->nr_rings; i++)
+		msm_gem_kernel_put(a6xx_gpu->preempt_bo[i], gpu->aspace);
+}
+
+void a6xx_preempt_init(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_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(a6xx_gpu, gpu->rb[i]))
+			goto fail;
+	}
+
+	/* TODO: make this configurable? */
+	a6xx_gpu->preempt_level = 1;
+	a6xx_gpu->uses_gmem = 1;
+	a6xx_gpu->skip_save_restore = 1;
+
+	a6xx_gpu->preempt_postamble_ptr  = msm_gem_kernel_new(gpu->dev,
+			PAGE_SIZE,
+			MSM_BO_WC | MSM_BO_MAP_PRIV | MSM_BO_GPU_READONLY,
+			gpu->aspace, &a6xx_gpu->preempt_postamble_bo,
+			&a6xx_gpu->preempt_postamble_iova);
+
+	preempt_prepare_postamble(a6xx_gpu);
+
+	if (IS_ERR(a6xx_gpu->preempt_postamble_ptr))
+		goto fail;
+
+	timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
+
+	return;
+fail:
+	/*
+	 * On any failure our adventure is over. Clean up and
+	 * set nr_rings to 1 to force preemption off
+	 */
+	a6xx_preempt_fini(gpu);
+	gpu->nr_rings = 1;
+
+	DRM_DEV_ERROR(&gpu->pdev->dev,
+				  "preemption init failed, disabling preemption\n");
+
+	return;
+}