]> git.ipfire.org Git - thirdparty/kernel/linux.git/commitdiff
drm/msm/a8xx: Preemption support for A840
authorAkhil P Oommen <akhilpo@oss.qualcomm.com>
Fri, 27 Mar 2026 00:14:04 +0000 (05:44 +0530)
committerRob Clark <robin.clark@oss.qualcomm.com>
Tue, 31 Mar 2026 20:47:30 +0000 (13:47 -0700)
The programing sequence related to preemption is unchanged from A7x. But
there is some code churn due to register shuffling in A8x. So, split out
the common code into a header file for code sharing and add/update
additional changes required to support preemption feature on A8x GPUs.

Finally, enable the preemption quirk in A840's catalog to enable this
feature.

Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/714682/
Message-ID: <20260327-a8xx-gpu-batch2-v2-15-2b53c38d2101@oss.qualcomm.com>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
drivers/gpu/drm/msm/Makefile
drivers/gpu/drm/msm/adreno/a6xx_catalog.c
drivers/gpu/drm/msm/adreno/a6xx_gpu.c
drivers/gpu/drm/msm/adreno/a6xx_gpu.h
drivers/gpu/drm/msm/adreno/a6xx_preempt.c
drivers/gpu/drm/msm/adreno/a6xx_preempt.h [new file with mode: 0644]
drivers/gpu/drm/msm/adreno/a8xx_gpu.c
drivers/gpu/drm/msm/adreno/a8xx_preempt.c [new file with mode: 0644]

index 8b94c5f1cb68e35b91b699338ae120097125191e..ba45e99be05b805e101f6ca18ca845ef2f13b48b 100644 (file)
@@ -25,6 +25,7 @@ adreno-y := \
        adreno/a6xx_hfi.o \
        adreno/a6xx_preempt.o \
        adreno/a8xx_gpu.o \
+       adreno/a8xx_preempt.o \
 
 adreno-$(CONFIG_DEBUG_FS) += adreno/a5xx_debugfs.o \
 
index 53548f6e891b97eec3d9e28880fbd43c33c4d39e..21f5a685196b937b9dc21e9120b5ca93207d4935 100644 (file)
@@ -2120,6 +2120,7 @@ static const struct adreno_info a8xx_gpus[] = {
                .inactive_period = DRM_MSM_INACTIVE_PERIOD,
                .quirks = ADRENO_QUIRK_HAS_CACHED_COHERENT |
                          ADRENO_QUIRK_HAS_HW_APRIV |
+                         ADRENO_QUIRK_PREEMPTION |
                          ADRENO_QUIRK_IFPC,
                .funcs = &a8xx_gpu_funcs,
                .a6xx = &(const struct a6xx_info) {
index fb52557e22d82a53d2e4d0970aa2111fc94383ca..ae592022bebcd7e2bd78e779df77ad782823ccdb 100644 (file)
@@ -410,7 +410,7 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
        a6xx_flush(gpu, ring);
 }
 
-static void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
+void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
                struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue)
 {
        u64 preempt_postamble;
@@ -620,7 +620,10 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
        a6xx_flush(gpu, ring);
 
        /* Check to see if we need to start preemption */
-       a6xx_preempt_trigger(gpu);
+       if (adreno_is_a8xx(adreno_gpu))
+               a8xx_preempt_trigger(gpu);
+       else
+               a6xx_preempt_trigger(gpu);
 }
 
 static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
index a4434a6a56dd84dc5b5d96d97f3cdadceb32b6a2..eb431e5e00b1af21bb50fbdc70959d4d97acad4b 100644 (file)
@@ -278,6 +278,8 @@ void a6xx_preempt_hw_init(struct msm_gpu *gpu);
 void a6xx_preempt_trigger(struct msm_gpu *gpu);
 void a6xx_preempt_irq(struct msm_gpu *gpu);
 void a6xx_preempt_fini(struct msm_gpu *gpu);
+void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
+               struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue);
 int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
                struct msm_gpu_submitqueue *queue);
 void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
@@ -327,6 +329,9 @@ void a8xx_gpu_get_slice_info(struct msm_gpu *gpu);
 int a8xx_hw_init(struct msm_gpu *gpu);
 irqreturn_t a8xx_irq(struct msm_gpu *gpu);
 void a8xx_llc_activate(struct a6xx_gpu *a6xx_gpu);
+void a8xx_preempt_hw_init(struct msm_gpu *gpu);
+void a8xx_preempt_trigger(struct msm_gpu *gpu);
+void a8xx_preempt_irq(struct msm_gpu *gpu);
 bool a8xx_progress(struct msm_gpu *gpu, struct msm_ringbuffer *ring);
 void a8xx_recover(struct msm_gpu *gpu);
 #endif /* __A6XX_GPU_H__ */
index 747a22afad9f6fe2c7848e787bab67155b92e71c..df4cbf42e9a40fbe267a33f7463b5b7fc4116e25 100644 (file)
@@ -6,85 +6,10 @@
 #include "msm_gem.h"
 #include "a6xx_gpu.h"
 #include "a6xx_gmu.xml.h"
+#include "a6xx_preempt.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 a6xx_gpu *a6xx_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);
-
-               a6xx_fenced_write(a6xx_gpu, REG_A6XX_CP_RB_WPTR, wptr, BIT(0), false);
-
-               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,
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.h b/drivers/gpu/drm/msm/adreno/a6xx_preempt.h
new file mode 100644 (file)
index 0000000..df36c94
--- /dev/null
@@ -0,0 +1,82 @@
+/* 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 */
+/* Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. */
+
+/*
+ * 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 a6xx_gpu *a6xx_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);
+
+               a6xx_fenced_write(a6xx_gpu, REG_A6XX_CP_RB_WPTR, wptr, BIT(0), false);
+
+               ring->restore_wptr = false;
+       }
+
+       spin_unlock_irqrestore(&ring->preempt_lock, flags);
+}
+
+/* Return the highest priority ringbuffer with something in it */
+static inline 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;
+}
+
index d6782bdde067cdf2c95aa271098008b183aa1b89..ccfccc45133fda53168d3475ebd3d543f10268af 100644 (file)
@@ -473,6 +473,34 @@ done:
        a8xx_aperture_clear(gpu);
 }
 
+static int a8xx_preempt_start(struct msm_gpu *gpu)
+{
+       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+       struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+       struct msm_ringbuffer *ring = gpu->rb[0];
+
+       if (gpu->nr_rings <= 1)
+               return 0;
+
+       /* Turn CP protection off */
+       OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
+       OUT_RING(ring, 0);
+
+       a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, NULL);
+
+       /* Yield the floor on command completion */
+       OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
+       OUT_RING(ring, 0x00);
+       OUT_RING(ring, 0x00);
+       OUT_RING(ring, 0x00);
+       /* Generate interrupt on preemption completion */
+       OUT_RING(ring, 0x00);
+
+       a6xx_flush(gpu, ring);
+
+       return a8xx_idle(gpu, ring) ? 0 : -EINVAL;
+}
+
 static int a8xx_cp_init(struct msm_gpu *gpu)
 {
        struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
@@ -748,6 +776,8 @@ static int hw_init(struct msm_gpu *gpu)
        gpu_write64(gpu, REG_A6XX_CP_RB_RPTR_ADDR, shadowptr(a6xx_gpu, gpu->rb[0]));
        gpu_write64(gpu, REG_A8XX_CP_RB_RPTR_ADDR_BV, rbmemptr(gpu->rb[0], bv_rptr));
 
+       a8xx_preempt_hw_init(gpu);
+
        for (i = 0; i < gpu->nr_rings; i++)
                a6xx_gpu->shadow[i] = 0;
 
@@ -810,6 +840,9 @@ static int hw_init(struct msm_gpu *gpu)
        /* Enable hardware clockgating */
        a8xx_set_hwcg(gpu, true);
 out:
+       /* Last step - yield the ringbuffer */
+       a8xx_preempt_start(gpu);
+
        /*
         * Tell the GMU that we are done touching the GPU and it can start power
         * management
@@ -1219,11 +1252,11 @@ irqreturn_t a8xx_irq(struct msm_gpu *gpu)
 
        if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) {
                msm_gpu_retire(gpu);
-               a6xx_preempt_trigger(gpu);
+               a8xx_preempt_trigger(gpu);
        }
 
        if (status & A6XX_RBBM_INT_0_MASK_CP_SW)
-               a6xx_preempt_irq(gpu);
+               a8xx_preempt_irq(gpu);
 
        return IRQ_HANDLED;
 }
diff --git a/drivers/gpu/drm/msm/adreno/a8xx_preempt.c b/drivers/gpu/drm/msm/adreno/a8xx_preempt.c
new file mode 100644 (file)
index 0000000..3d8c33b
--- /dev/null
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. */
+
+#include "msm_gem.h"
+#include "a6xx_gpu.h"
+#include "a6xx_gmu.xml.h"
+#include "a6xx_preempt.h"
+#include "msm_mmu.h"
+#include "msm_gpu_trace.h"
+
+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_A8XX_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_POLL_ADDR_LO(
+                               REG_A8XX_RBBM_PERFCTR_SRAM_INIT_STATUS);
+       postamble[count++] = CP_WAIT_REG_MEM_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;
+}
+
+/*
+ * Set preemption keepalive vote. Please note that this vote is different from the one used in
+ * a8xx_irq()
+ */
+static void a8xx_preempt_keepalive_vote(struct msm_gpu *gpu, bool on)
+{
+       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+       struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+
+       gmu_write(&a6xx_gpu->gmu, REG_A8XX_GMU_PWR_COL_PREEMPT_KEEPALIVE, on);
+}
+
+void a8xx_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_A8XX_CP_CONTEXT_SWITCH_CNTL);
+       if (unlikely(status & A8XX_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(a6xx_gpu, a6xx_gpu->cur_ring);
+
+       set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+
+       a8xx_preempt_keepalive_vote(gpu, false);
+
+       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.
+        */
+       a8xx_preempt_trigger(gpu);
+}
+
+void a8xx_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_A8XX_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_ENABLE, 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 a8xx_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 = A8XX_CP_CONTEXT_SWITCH_CNTL_LEVEL(a6xx_gpu->preempt_level);
+
+       if (a6xx_gpu->skip_save_restore)
+               cntl |= A8XX_CP_CONTEXT_SWITCH_CNTL_SKIP_SAVE_RESTORE;
+
+       if (a6xx_gpu->uses_gmem)
+               cntl |= A8XX_CP_CONTEXT_SWITCH_CNTL_USES_GMEM;
+
+       cntl |= A8XX_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(a6xx_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);
+
+       /* Set the keepalive bit to keep the GPU ON until preemption is complete */
+       a8xx_preempt_keepalive_vote(gpu, true);
+
+       a6xx_fenced_write(a6xx_gpu,
+               REG_A8XX_CP_CONTEXT_SWITCH_SMMU_INFO, a6xx_gpu->preempt_smmu_iova[ring->id],
+               BIT(1), true);
+
+       a6xx_fenced_write(a6xx_gpu,
+               REG_A8XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
+               a6xx_gpu->preempt_iova[ring->id], BIT(1), true);
+
+       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 */
+       a6xx_fenced_write(a6xx_gpu, REG_A8XX_CP_CONTEXT_SWITCH_CNTL, cntl, BIT(1), false);
+}
+