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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 The Linux Foundation. All rights reserved.
*/
#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->preempt_lock, flags);
wptr = get_wptr(ring);
spin_unlock_irqrestore(&ring->preempt_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->preempt_lock, flags);
empty = (get_wptr(ring) == ring->memptrs->rptr);
spin_unlock_irqrestore(&ring->preempt_lock, flags);
if (!empty)
return ring;
}
return NULL;
}
static void a5xx_preempt_timer(struct timer_list *t)
{
struct a5xx_gpu *a5xx_gpu = from_timer(a5xx_gpu, t, preempt_timer);
struct msm_gpu *gpu = &a5xx_gpu->base.base;
struct drm_device *dev = gpu->dev;
if (!try_preempt_state(a5xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
return;
DRM_DEV_ERROR(dev->dev, "%s: preemption timed out\n", gpu->name);
kthread_queue_work(gpu->worker, &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->preempt_lock, flags);
a5xx_gpu->preempt[ring->id]->wptr = get_wptr(ring);
spin_unlock_irqrestore(&ring->preempt_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;
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);
DRM_DEV_ERROR(dev->dev, "%s: Preemption failed to complete\n",
gpu->name);
kthread_queue_work(gpu->worker, &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;
/* Always come up on rb 0 */
a5xx_gpu->cur_ring = gpu->rb[0];
/* No preemption if we only have one ring */
if (gpu->nr_rings == 1)
return;
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);
}
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;
void *counters;
struct drm_gem_object *bo = NULL, *counters_bo = NULL;
u64 iova = 0, counters_iova = 0;
ptr = msm_gem_kernel_new(gpu->dev,
A5XX_PREEMPT_RECORD_SIZE + A5XX_PREEMPT_COUNTER_SIZE,
MSM_BO_UNCACHED | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
/* The buffer to store counters needs to be unprivileged */
counters = msm_gem_kernel_new(gpu->dev,
A5XX_PREEMPT_COUNTER_SIZE,
MSM_BO_UNCACHED, gpu->aspace, &counters_bo, &counters_iova);
if (IS_ERR(counters)) {
msm_gem_kernel_put(bo, gpu->aspace, true);
return PTR_ERR(counters);
}
msm_gem_object_set_name(bo, "preempt");
msm_gem_object_set_name(counters_bo, "preempt_counters");
a5xx_gpu->preempt_bo[ring->id] = bo;
a5xx_gpu->preempt_counters_bo[ring->id] = counters_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 | AXXX_CP_RB_CNTL_NO_UPDATE;
ptr->rptr_addr = shadowptr(a5xx_gpu, ring);
ptr->counter = counters_iova;
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++) {
msm_gem_kernel_put(a5xx_gpu->preempt_bo[i], gpu->aspace, true);
msm_gem_kernel_put(a5xx_gpu->preempt_counters_bo[i],
gpu->aspace, true);
}
}
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;
}
}
timer_setup(&a5xx_gpu->preempt_timer, a5xx_preempt_timer, 0);
}