This patch adds a bit of infrastructure to give the different Adreno targets the flexibility to setup the submitqueues per their needs.

Signed-off-by: Sharat Masetty smasetty@codeaurora.org --- drivers/gpu/drm/msm/msm_gpu.h | 7 +++++++ drivers/gpu/drm/msm/msm_submitqueue.c | 15 +++++++++++++-- 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h index b824117..b9b86ef 100644 --- a/drivers/gpu/drm/msm/msm_gpu.h +++ b/drivers/gpu/drm/msm/msm_gpu.h @@ -69,6 +69,10 @@ struct msm_gpu_funcs { int (*debugfs_init)(struct msm_gpu *gpu, struct drm_minor *minor); #endif int (*gpu_busy)(struct msm_gpu *gpu, uint64_t *value); + int (*submitqueue_setup)(struct msm_gpu *gpu, + struct msm_gpu_submitqueue *queue); + void (*submitqueue_close)(struct msm_gpu *gpu, + struct msm_gpu_submitqueue *queue); };

struct msm_gpu { @@ -173,6 +177,9 @@ struct msm_gpu_submitqueue { int faults; struct list_head node; struct kref ref; + struct msm_gpu *gpu; + struct drm_gem_object *bo; + uint64_t bo_iova; };

static inline void gpu_write(struct msm_gpu *gpu, u32 reg, u32 data) diff --git a/drivers/gpu/drm/msm/msm_submitqueue.c b/drivers/gpu/drm/msm/msm_submitqueue.c index 5115f75..1e696da 100644 --- a/drivers/gpu/drm/msm/msm_submitqueue.c +++ b/drivers/gpu/drm/msm/msm_submitqueue.c @@ -18,6 +18,10 @@ void msm_submitqueue_destroy(struct kref *kref) { struct msm_gpu_submitqueue *queue = container_of(kref, struct msm_gpu_submitqueue, ref); + struct msm_gpu *gpu = queue->gpu; + + if (gpu && gpu->funcs->submitqueue_close) + gpu->funcs->submitqueue_close(gpu, queue);

kfree(queue); } @@ -65,6 +69,7 @@ int msm_submitqueue_create(struct drm_device *drm, struct msm_file_private *ctx, { struct msm_drm_private *priv = drm->dev_private; struct msm_gpu_submitqueue *queue; + struct msm_gpu *gpu = priv->gpu;

if (!ctx) return -ENODEV; @@ -77,11 +82,14 @@ int msm_submitqueue_create(struct drm_device *drm, struct msm_file_private *ctx, kref_init(&queue->ref); queue->flags = flags;

- if (priv->gpu) { - if (prio >= priv->gpu->nr_rings) + if (gpu) { + if (prio >= gpu->nr_rings) { + kfree(queue); return -EINVAL; + }

queue->prio = prio; + queue->gpu = gpu; }

write_lock(&ctx->queuelock); @@ -95,6 +103,9 @@ int msm_submitqueue_create(struct drm_device *drm, struct msm_file_private *ctx,

write_unlock(&ctx->queuelock);

+ if (gpu && gpu->funcs->submitqueue_setup) + gpu->funcs->submitqueue_setup(gpu, queue); + return 0; }

This patch implements preemption feature for A6xx targets, this allows the GPU to switch to a higher priority ringbuffer if one is ready. A6XX hardware as such supports multiple levels of preemption granularities, ranging from coarse grained(ringbuffer level) to a more fine grained such as draw-call level or a bin boundary level preemption. This patch enables the basic preemption level, with more fine grained preemption support to follow.

Signed-off-by: Sharat Masetty smasetty@codeaurora.org --- drivers/gpu/drm/msm/Makefile | 1 + drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 44 ++++ drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 146 +++++++++++- drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 136 +++++++++++ drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 383 ++++++++++++++++++++++++++++++ 5 files changed, 708 insertions(+), 2 deletions(-) create mode 100644 drivers/gpu/drm/msm/adreno/a6xx_preempt.c

diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile index 0b6e150..1978312 100644 --- a/drivers/gpu/drm/msm/Makefile +++ b/drivers/gpu/drm/msm/Makefile @@ -13,6 +13,7 @@ msm-y := \ adreno/a6xx_gpu.o \ adreno/a6xx_gmu.o \ adreno/a6xx_hfi.o \ + adreno/a6xx_preempt.o \ hdmi/hdmi.o \ hdmi/hdmi_audio.o \ hdmi/hdmi_bridge.o \ diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c index 8d732e0..5c2a68a 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c @@ -1145,6 +1145,50 @@ void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu) iommu_domain_free(gmu->domain); }

+#define A6XX_GMU_FENCED_WRITE_SLEEP_US 10 /* Sleep time between reads in us */ +#define A6XX_GMU_FENCED_WRITE_TIMEOUT 600 /* Timeout in us */ +int a6xx_gmu_fenced_write(struct a6xx_gpu *a6xx_gpu, unsigned int reg, + unsigned int value, unsigned int fence_mask) +{ + struct a6xx_gmu *gmu = &a6xx_gpu->gmu; + struct adreno_gpu *adreno_gpu = &a6xx_gpu->base; + struct msm_gpu *gpu = &adreno_gpu->base; + unsigned int status; + ktime_t timeout = ktime_add_us(ktime_get(), + A6XX_GMU_FENCED_WRITE_TIMEOUT); + + /* Write to the GPU register */ + gpu_write(gpu, reg, value); + + might_sleep_if(A6XX_GMU_FENCED_WRITE_SLEEP_US); + for (;;) { + status = gmu_read(gmu, REG_A6XX_GMU_AHB_FENCE_STATUS); + /* + * If no bits of the fence_mask are set in the status, then the + * write was successful + */ + if (!(status & fence_mask)) + return 0; + + if (ktime_compare(ktime_get(), timeout) > 0) { + /* Timed out, but check one last time */ + status = gmu_read(gmu, REG_A6XX_GMU_AHB_FENCE_STATUS); + if (!(status & fence_mask)) + return 0; + + break; + } + + usleep_range((A6XX_GMU_FENCED_WRITE_SLEEP_US >> 2) + 1, + A6XX_GMU_FENCED_WRITE_SLEEP_US); + + /* Try writing again */ + gpu_write(gpu, reg, value); + } + + return -ETIMEDOUT; +} + int a6xx_gmu_probe(struct a6xx_gpu *a6xx_gpu, struct device_node *node) { struct a6xx_gmu *gmu = &a6xx_gpu->gmu; diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c index c72434b..b1a80ec 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c @@ -151,6 +151,8 @@ bool a6xx_idle(struct msm_gpu *gpu, struct msm_ringbuffer *ring)

static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring) { + struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu); + struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu); uint32_t wptr; unsigned long flags;

@@ -167,16 +169,52 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring) /* Make sure everything is posted before making a decision */ mb();

- gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr); + /* Update HW if this is the current ring and we are not in preempt*/ + if (a6xx_gpu->cur_ring == ring && !a6xx_in_preempt(a6xx_gpu)) + gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr); }

static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit, struct msm_file_private *ctx) { + struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu); + struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu); struct msm_drm_private *priv = gpu->dev->dev_private; struct msm_ringbuffer *ring = submit->ring; + uint64_t scratch_dest = SCRATCH_USER_CTX_IOVA(ring->id, a6xx_gpu); unsigned int i;

+ /* + * If preemption is enabled, then set the pseudo register for the save + * sequence + */ + if (gpu->nr_rings > 1) { + struct msm_gpu_submitqueue *queue = submit->queue; + + OUT_PKT7(ring, CP_SET_PSEUDO_REG, 6); + + /* privileged and non secure buffer save */ + OUT_RING(ring, SAVE_REG_PRIV_NON_SECURE_SAVE_ADDR_ID); + OUT_RING(ring, lower_32_bits(a6xx_gpu->preempt_iova[ring->id])); + OUT_RING(ring, upper_32_bits(a6xx_gpu->preempt_iova[ring->id])); + + /* user context buffer save */ + OUT_RING(ring, SAVE_REG_NON_PRIV_SAVE_ADDR_ID); + OUT_RING(ring, lower_32_bits(queue->bo_iova)); + OUT_RING(ring, upper_32_bits(queue->bo_iova)); + + /* + * Ask CP to save the user context buffer's iova address to a + * scratch memory region, this is needed if the CP preempts + * this ring in between this submit's IB list. + */ + OUT_PKT7(ring, CP_MEM_WRITE, 4); + OUT_RING(ring, lower_32_bits(scratch_dest)); + OUT_RING(ring, upper_32_bits(scratch_dest)); + OUT_RING(ring, lower_32_bits(queue->bo_iova)); + OUT_RING(ring, upper_32_bits(queue->bo_iova)); + } + /* Invalidate CCU depth and color */ OUT_PKT7(ring, CP_EVENT_WRITE, 1); OUT_RING(ring, PC_CCU_INVALIDATE_DEPTH); @@ -184,6 +222,14 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit, OUT_PKT7(ring, CP_EVENT_WRITE, 1); OUT_RING(ring, PC_CCU_INVALIDATE_COLOR);

+ if (gpu->nr_rings > 1) { + /* Indicate the beginning of IB list, this will implicitly turn + * on preemption. + */ + OUT_PKT7(ring, CP_SET_MARKER, 1); + OUT_RING(ring, 0XD); + } + /* Submit the commands */ for (i = 0; i < submit->nr_cmds; i++) { switch (submit->cmd[i].type) { @@ -201,6 +247,14 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit, } }

+ if (gpu->nr_rings > 1) { + /* Indicate the end of IB list, this will implicitly turn + * off preemption. + */ + OUT_PKT7(ring, CP_SET_MARKER, 1); + OUT_RING(ring, 0XE); + } + /* Write the fence to the scratch register */ OUT_PKT4(ring, REG_A6XX_CP_SCRATCH_REG(2), 1); OUT_RING(ring, submit->seqno); @@ -215,7 +269,38 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit, OUT_RING(ring, upper_32_bits(rbmemptr(ring, fence))); OUT_RING(ring, submit->seqno);

+ /* If preemption is enabled */ + if (gpu->nr_rings > 1) { + /* + * Reset the scratch region as we are done with the + * IB list of this submission + */ + OUT_PKT7(ring, CP_MEM_WRITE, 4); + OUT_RING(ring, lower_32_bits(scratch_dest)); + OUT_RING(ring, upper_32_bits(scratch_dest)); + OUT_RING(ring, 0x00); + OUT_RING(ring, 0x00); + + /* Yield the floor on command completion */ + OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4); + + /* + * If dword[2:1] are non zero, they specify an address for + * the CP to write the value of dword[3] to on preemption + * complete. Write 0 to skip the write + */ + OUT_RING(ring, 0x00); + OUT_RING(ring, 0x00); + /* Data value - not used if the address above is 0 */ + OUT_RING(ring, 0x01); + /* generate interrupt on preemption completion */ + OUT_RING(ring, 0x00); + } + a6xx_flush(gpu, ring); + + /* Check to see if we need to start preemption */ + a6xx_preempt_trigger(gpu); }

static const struct { @@ -413,11 +498,54 @@ static int a6xx_ucode_init(struct msm_gpu *gpu) return 0; }

+static int a6xx_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); + + OUT_PKT7(ring, CP_SET_PSEUDO_REG, 6); + + /* Privileged and non-secure */ + OUT_RING(ring, SAVE_REG_PRIV_NON_SECURE_SAVE_ADDR_ID); + OUT_RING(ring, lower_32_bits(a6xx_gpu->preempt_iova[ring->id])); + OUT_RING(ring, upper_32_bits(a6xx_gpu->preempt_iova[ring->id])); + + /* Privileged and secure. We don't do secure yet, so reset to 0 */ + OUT_RING(ring, SAVE_REG_PRIV_SECURE_SAVE_ADDR_ID); + OUT_RING(ring, 0x00); + OUT_RING(ring, 0x00); + + /* Turn CP protection back on */ + OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1); + OUT_RING(ring, 1); + + /* 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); + + gpu->funcs->flush(gpu, ring); + + return a6xx_idle(gpu, ring) ? 0 : -EINVAL; +} + #define A6XX_INT_MASK (A6XX_RBBM_INT_0_MASK_CP_AHB_ERROR | \ A6XX_RBBM_INT_0_MASK_RBBM_ATB_ASYNCFIFO_OVERFLOW | \ A6XX_RBBM_INT_0_MASK_CP_HW_ERROR | \ A6XX_RBBM_INT_0_MASK_CP_IB2 | \ A6XX_RBBM_INT_0_MASK_CP_IB1 | \ + A6XX_RBBM_INT_0_MASK_CP_SW | \ A6XX_RBBM_INT_0_MASK_CP_RB | \ A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS | \ A6XX_RBBM_INT_0_MASK_RBBM_ATB_BUS_OVERFLOW | \ @@ -557,6 +685,8 @@ static int a6xx_hw_init(struct msm_gpu *gpu) if (ret) goto out;

+ a6xx_preempt_hw_init(gpu); + ret = a6xx_ucode_init(gpu); if (ret) goto out; @@ -586,6 +716,8 @@ static int a6xx_hw_init(struct msm_gpu *gpu) gpu_write(gpu, REG_A6XX_RBBM_SECVID_TRUST_CNTL, 0x0); }

+ /* Last step - yield the ringbuffer */ + a6xx_preempt_start(gpu); out: /* * Tell the GMU that we are done touching the GPU and it can start power @@ -731,8 +863,13 @@ static irqreturn_t a6xx_irq(struct msm_gpu *gpu) if (status & A6XX_RBBM_INT_0_MASK_UCHE_OOB_ACCESS) dev_err_ratelimited(&gpu->pdev->dev, "UCHE | Out of bounds access\n");

- if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) + if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) { msm_gpu_retire(gpu); + a6xx_preempt_trigger(gpu); + } + + if (status & A6XX_RBBM_INT_0_MASK_CP_SW) + a6xx_preempt_irq(gpu);

return IRQ_HANDLED; } @@ -874,6 +1011,8 @@ static void a6xx_destroy(struct msm_gpu *gpu) .active_ring = a6xx_active_ring, .irq = a6xx_irq, .destroy = a6xx_destroy, + .submitqueue_setup = a6xx_preempt_submitqueue_setup, + .submitqueue_close = a6xx_preempt_submitqueue_close, #ifdef CONFIG_DEBUG_FS .show = a6xx_show, #endif @@ -923,5 +1062,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev) msm_mmu_set_fault_handler(gpu->aspace->mmu, gpu, a6xx_fault_handler);

+ /* Set up the preemption specific bits and pieces for each ringbuffer */ + a6xx_preempt_init(gpu); + return gpu; } diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h index 06e93fd..aca1d7d 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h @@ -28,12 +28,126 @@ struct a6xx_gpu { uint64_t sqe_iova;

struct msm_ringbuffer *cur_ring; + struct msm_ringbuffer *next_ring; + + struct drm_gem_object *preempt_bo[MSM_GPU_MAX_RINGS]; + struct a6xx_preempt_record *preempt[MSM_GPU_MAX_RINGS]; + uint64_t preempt_iova[MSM_GPU_MAX_RINGS]; + + atomic_t preempt_state; + struct timer_list preempt_timer; + + unsigned int preempt_level; + bool uses_gmem; + bool skip_save_restore; + + struct drm_gem_object *scratch_bo; + void *scratch_ptr; + uint64_t scratch_iova;

struct a6xx_gmu gmu; };

#define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)

+#define SCRATCH_USER_CTX_IOVA(ring_id, a6xx_gpu) \ + (a6xx_gpu->scratch_iova + (ring_id * sizeof(uint64_t))) + +/* + * In order to do lockless preemption we use a simple state machine to progress + * through the process. + * + * PREEMPT_NONE - no preemption in progress. Next state START. + * PREEMPT_START - The trigger is evaluating if preemption is possible. Next + * states: TRIGGERED, NONE + * PREEMPT_ABORT - An intermediate state before moving back to NONE. Next + * state: NONE. + * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next + * states: FAULTED, PENDING + * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger + * recovery. Next state: N/A + * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is + * checking the success of the operation. Next state: FAULTED, NONE. + */ + +enum a6xx_preempt_state { + PREEMPT_NONE = 0, + PREEMPT_START, + PREEMPT_ABORT, + PREEMPT_TRIGGERED, + PREEMPT_FAULTED, + PREEMPT_PENDING, +}; + +/* + * ID values used by SET_PSEUDO_REG PM4 command. These determine which of the + * various internal CP registers to write to. Used in the save/restore + * preemption sequence. + */ +enum a6xx_set_pseudo_register { + SAVE_REG_SMMU_INFO_ID = 0, + SAVE_REG_PRIV_NON_SECURE_SAVE_ADDR_ID = 1, + SAVE_REG_PRIV_SECURE_SAVE_ADDR_ID = 2, + SAVE_REG_NON_PRIV_SAVE_ADDR_ID = 3, + SAVE_REG_COUNTER_ID = 4, +}; + +/* + * struct a6xx_preempt_record is a shared buffer between the microcode and the + * CPU to store the state for preemption. The record itself is much larger + * (2112k) but most of that is used by the CP for storage. + * + * There is a preemption record assigned per ringbuffer. When the CPU triggers a + * preemption, it fills out the record with the useful information (wptr, ring + * base, etc) and the microcode uses that information to set up the CP following + * the preemption. When a ring is switched out, the CP will save the ringbuffer + * state back to the record. In this way, once the records are properly set up + * the CPU can quickly switch back and forth between ringbuffers by only + * updating a few registers (often only the wptr). + * + * These are the CPU aware registers in the record: + * @magic: Must always be 0xAE399D6EUL + * @info: Type of the record - written 0 by the CPU, updated by the CP + * @errno: preemption error record + * @data: Data field in YIELD and SET_MARKER packets, Written and used by CP + * @cntl: Value of RB_CNTL written by CPU, save/restored by CP + * @rptr: Value of RB_RPTR written by CPU, save/restored by CP + * @wptr: Value of RB_WPTR written by CPU, save/restored by CP + * @_pad: Reserved/padding + * @rptr_addr: Value of RB_RPTR_ADDR_LO|HI written by CPU, save/restored by CP + * @rbase: Value of RB_BASE written by CPU, save/restored by CP + * @counter: GPU address of the storage area for the preemption counters + */ +struct a6xx_preempt_record { + u32 magic; + u32 info; + u32 errno; + u32 data; + u32 cntl; + u32 rptr; + u32 wptr; + u32 _pad; + u64 rptr_addr; + u64 rbase; + u64 counter; +}; + +#define A6XX_PREEMPT_RECORD_MAGIC 0xAE399D6EUL + +/* + * Even though the structure above is only a few bytes, we need a full 2112k to + * store the entire preemption record from the CP + */ +#define A6XX_PREEMPT_RECORD_SIZE (2112 * 1024) + +/* + * The preemption counter block is a storage area for the value of the + * preemption counters that are saved immediately before context switch. We + * append it on to the end of the allocation for the preemption record. + */ +#define A6XX_PREEMPT_COUNTER_SIZE (16 * 4) + +#define A6XX_PREEMPT_USER_RECORD_SIZE (192 * 1024) /* * Given a register and a count, return a value to program into * REG_CP_PROTECT_REG(n) - this will block both reads and writes for _len @@ -66,4 +180,26 @@ struct a6xx_gpu { int a6xx_gmu_probe(struct a6xx_gpu *a6xx_gpu, struct device_node *node); void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu);

+int a6xx_gmu_fenced_write(struct a6xx_gpu *a6xx_gpu, unsigned int reg, + unsigned int value, unsigned int fence_mask); + +void a6xx_preempt_init(struct msm_gpu *gpu); +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); +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu, + struct msm_gpu_submitqueue *queue); +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu, + struct msm_gpu_submitqueue *queue); + +/* Return true if we are in a preempt state */ +static inline bool a6xx_in_preempt(struct a6xx_gpu *a6xx_gpu) +{ + int preempt_state = atomic_read(&a6xx_gpu->preempt_state); + + return !(preempt_state == PREEMPT_NONE || + preempt_state == PREEMPT_ABORT); +} + #endif /* __A6XX_GPU_H__ */ 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 0000000..60df6c5 --- /dev/null +++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c @@ -0,0 +1,383 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */ + +#include "msm_gem.h" +#include "a6xx_gpu.h" +#include "a6xx_gmu.xml.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; + + if (!ring) + return; + + spin_lock_irqsave(&ring->lock, flags); + wptr = get_wptr(ring); + spin_unlock_irqrestore(&ring->lock, flags); + + gpu_write(gpu, REG_A6XX_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 a6xx_preempt_timer(unsigned long data) +{ + struct a6xx_gpu *a6xx_gpu = (struct a6xx_gpu *) data; + struct msm_gpu *gpu = &a6xx_gpu->base.base; + struct drm_device *dev = gpu->dev; + struct msm_drm_private *priv = dev->dev_private; + + if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED)) + return; + + dev_err(dev->dev, "%s: preemption timed out\n", gpu->name); + queue_work(priv->wq, &gpu->recover_work); +} + +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; + struct msm_drm_private *priv = dev->dev_private; + + if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING)) + return; + + /* Delete the preemption watchdog timer */ + del_timer(&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 & 0x1)) { + set_preempt_state(a6xx_gpu, PREEMPT_FAULTED); + dev_err(dev->dev, "%s: Preemption failed to complete\n", + gpu->name); + queue_work(priv->wq, &gpu->recover_work); + return; + } + + a6xx_gpu->cur_ring = a6xx_gpu->next_ring; + a6xx_gpu->next_ring = NULL; + + update_wptr(gpu, a6xx_gpu->cur_ring); + + set_preempt_state(a6xx_gpu, PREEMPT_NONE); +} + +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++) { + a6xx_gpu->preempt[i]->wptr = 0; + a6xx_gpu->preempt[i]->rptr = 0; + a6xx_gpu->preempt[i]->info = 0; + a6xx_gpu->preempt[i]->data = 0; + a6xx_gpu->preempt[i]->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_LO, + REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO_HI, 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); + + /* Always come up on rb 0 */ + a6xx_gpu->cur_ring = gpu->rb[0]; +} + +#define FENCE_STATUS_WRITEDROPPED0_MASK 0x1 +#define FENCE_STATUS_WRITEDROPPED1_MASK 0x2 +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; + uint64_t user_ctx_iova; + unsigned int cntl; + + 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(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) + return; + + cntl = (((a6xx_gpu->preempt_level << 6) & 0xC0) | + ((a6xx_gpu->skip_save_restore << 9) & 0x200) | + ((a6xx_gpu->uses_gmem << 8) & 0x100) | 0x1); + + /* 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_ABORT); + update_wptr(gpu, a6xx_gpu->cur_ring); + set_preempt_state(a6xx_gpu, PREEMPT_NONE); + return; + } + + spin_lock_irqsave(&ring->lock, flags); + a6xx_gpu->preempt[ring->id]->wptr = get_wptr(ring); + spin_unlock_irqrestore(&ring->lock, flags); + + /* + * The GPU power collapsing between the following preemption register + * writes can lead to a prolonged preemption trigger sequence, so we + * set a keepalive bit to make sure the GPU is not power collapsed by + * the GMU during this time. The first fenced write will make sure to + * wake up the GPU(if it was power collapsed) and from there on it is + * not going to be power collapsed until we close the keepalive window + * by resetting the keepalive bit. + */ + gmu_rmw(&a6xx_gpu->gmu, REG_A6XX_GMU_AO_SPARE_CNTL, 0x0, 0x2); + + a6xx_gmu_fenced_write(a6xx_gpu, + REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR_LO, + lower_32_bits(a6xx_gpu->preempt_iova[ring->id]), + FENCE_STATUS_WRITEDROPPED1_MASK); + + a6xx_gmu_fenced_write(a6xx_gpu, + REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR_HI, + upper_32_bits(a6xx_gpu->preempt_iova[ring->id]), + FENCE_STATUS_WRITEDROPPED1_MASK); + + /* + * Use the user context iova from the scratch memory that the CP may + * have written as part of the ring switch out. + */ + user_ctx_iova = *((uint64_t *)a6xx_gpu->scratch_ptr + ring->id); + + a6xx_gmu_fenced_write(a6xx_gpu, + REG_A6XX_CP_CONTEXT_SWITCH_NON_PRIV_RESTORE_ADDR_LO, + lower_32_bits(user_ctx_iova), + FENCE_STATUS_WRITEDROPPED1_MASK); + + a6xx_gmu_fenced_write(a6xx_gpu, + REG_A6XX_CP_CONTEXT_SWITCH_NON_PRIV_RESTORE_ADDR_HI, + upper_32_bits(user_ctx_iova), + FENCE_STATUS_WRITEDROPPED1_MASK); + + a6xx_gpu->next_ring = ring; + + /* Start a timer to catch a stuck preemption */ + mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000)); + + /* Set the preemption state to triggered */ + set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED); + + /* Make sure everything is written before hitting the button */ + wmb(); + + /* Trigger the preemption */ + a6xx_gmu_fenced_write(a6xx_gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl, + FENCE_STATUS_WRITEDROPPED1_MASK); + + /* Close the GPU keelaplive window */ + gmu_rmw(&a6xx_gpu->gmu, REG_A6XX_GMU_AO_SPARE_CNTL, 0x2, 0x0); +} + +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 a6xx_preempt_record *ptr; + struct drm_gem_object *bo = NULL; + u64 iova = 0; + + ptr = msm_gem_kernel_new(gpu->dev, + A6XX_PREEMPT_RECORD_SIZE + A6XX_PREEMPT_COUNTER_SIZE, + MSM_BO_UNCACHED, gpu->aspace, &bo, &iova); + + if (IS_ERR(ptr)) + return PTR_ERR(ptr); + + a6xx_gpu->preempt_bo[ring->id] = bo; + a6xx_gpu->preempt_iova[ring->id] = iova; + a6xx_gpu->preempt[ring->id] = ptr; + + /* Set up the defaults on the preemption record */ + ptr->magic = A6XX_PREEMPT_RECORD_MAGIC; + ptr->info = 0; + ptr->data = 0; + ptr->rptr = 0; + ptr->wptr = 0; + ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT; + ptr->rptr_addr = rbmemptr(ring, rptr); + ptr->rbase = ring->iova; + ptr->counter = iova + A6XX_PREEMPT_RECORD_SIZE; + + 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++) { + if (!a6xx_gpu->preempt_bo[i]) + continue; + + msm_gem_put_vaddr(a6xx_gpu->preempt_bo[i]); + + if (a6xx_gpu->preempt_iova[i]) + msm_gem_put_iova(a6xx_gpu->preempt_bo[i], gpu->aspace); + + drm_gem_object_unreference(a6xx_gpu->preempt_bo[i]); + a6xx_gpu->preempt_bo[i] = NULL; + } +} + +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 = 0; + a6xx_gpu->uses_gmem = 1; + a6xx_gpu->skip_save_restore = 0; + + a6xx_gpu->scratch_ptr = msm_gem_kernel_new(gpu->dev, + gpu->nr_rings * sizeof(uint64_t), MSM_BO_WC, + gpu->aspace, &a6xx_gpu->scratch_bo, + &a6xx_gpu->scratch_iova); + + if (IS_ERR(a6xx_gpu->scratch_ptr)) + goto fail; + + setup_timer(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, + (unsigned long) a6xx_gpu); + + 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; + + return; +} + +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu, + struct msm_gpu_submitqueue *queue) +{ + if (!queue->bo) + return; + + msm_gem_put_iova(queue->bo, gpu->aspace); + msm_gem_put_vaddr(queue->bo); + drm_gem_object_unreference_unlocked(queue->bo); +} + +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu, + struct msm_gpu_submitqueue *queue) +{ + void *ptr; + + /* + * Create a per submitqueue buffer for the CP to save and restore user + * specific information such as the VPC streamout data. + */ + ptr = msm_gem_kernel_new(gpu->dev, A6XX_PREEMPT_USER_RECORD_SIZE, + MSM_BO_WC, gpu->aspace, &queue->bo, &queue->bo_iova); + + if (IS_ERR(ptr)) + return PTR_ERR(ptr); + + return 0; +}

The preemption state machine related code is same across Adreno targets, so move the common code to a common header file to avoid code duplication.

Signed-off-by: Sharat Masetty smasetty@codeaurora.org --- drivers/gpu/drm/msm/adreno/a5xx_gpu.h | 26 --------------- drivers/gpu/drm/msm/adreno/a5xx_preempt.c | 55 +++++++++---------------------- drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 26 --------------- drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 55 +++++++++---------------------- drivers/gpu/drm/msm/adreno/adreno_gpu.h | 54 ++++++++++++++++++++++++++++++ 5 files changed, 84 insertions(+), 132 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.h b/drivers/gpu/drm/msm/adreno/a5xx_gpu.h index 7d71860..45535f7 100644 --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.h +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.h @@ -54,32 +54,6 @@ struct a5xx_gpu { #endif

/* - * In order to do lockless preemption we use a simple state machine to progress - * through the process. - * - * PREEMPT_NONE - no preemption in progress. Next state START. - * PREEMPT_START - The trigger is evaulating if preemption is possible. Next - * states: TRIGGERED, NONE - * PREEMPT_ABORT - An intermediate state before moving back to NONE. Next - * state: NONE. - * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next - * states: FAULTED, PENDING - * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger - * recovery. Next state: N/A - * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is - * checking the success of the operation. Next state: FAULTED, NONE. - */ - -enum preempt_state { - PREEMPT_NONE = 0, - PREEMPT_START, - PREEMPT_ABORT, - PREEMPT_TRIGGERED, - PREEMPT_FAULTED, - PREEMPT_PENDING, -}; - -/* * struct a5xx_preempt_record is a shared buffer between the microcode and the * CPU to store the state for preemption. The record itself is much larger * (64k) but most of that is used by the CP for storage. diff --git a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c index 40f4840..faf844b 100644 --- a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c +++ b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c @@ -14,37 +14,6 @@ #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) { @@ -89,7 +58,8 @@ static void a5xx_preempt_timer(unsigned long data) struct drm_device *dev = gpu->dev; struct msm_drm_private *priv = dev->dev_private;

- if (!try_preempt_state(a5xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED)) + if (!adreno_try_preempt_state(&a5xx_gpu->preempt_state, + PREEMPT_TRIGGERED, PREEMPT_FAULTED)) return;

dev_err(dev->dev, "%s: preemption timed out\n", gpu->name); @@ -111,7 +81,8 @@ void a5xx_preempt_trigger(struct msm_gpu *gpu) * 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)) + if (!adreno_try_preempt_state(&a5xx_gpu->preempt_state, + PREEMPT_NONE, PREEMPT_START)) return;

/* Get the next ring to preempt to */ @@ -134,9 +105,11 @@ void a5xx_preempt_trigger(struct msm_gpu *gpu) * and can safely update the write pointer. */

- set_preempt_state(a5xx_gpu, PREEMPT_ABORT); + adreno_set_preempt_state(&a5xx_gpu->preempt_state, + PREEMPT_ABORT); update_wptr(gpu, a5xx_gpu->cur_ring); - set_preempt_state(a5xx_gpu, PREEMPT_NONE); + adreno_set_preempt_state(&a5xx_gpu->preempt_state, + PREEMPT_NONE); return; }

@@ -156,7 +129,7 @@ void a5xx_preempt_trigger(struct msm_gpu *gpu) mod_timer(&a5xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));

/* Set the preemption state to triggered */ - set_preempt_state(a5xx_gpu, PREEMPT_TRIGGERED); + adreno_set_preempt_state(&a5xx_gpu->preempt_state, PREEMPT_TRIGGERED);

/* Make sure everything is written before hitting the button */ wmb(); @@ -173,7 +146,8 @@ void a5xx_preempt_irq(struct msm_gpu *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)) + if (!adreno_try_preempt_state(&a5xx_gpu->preempt_state, + PREEMPT_TRIGGERED, PREEMPT_PENDING)) return;

/* Delete the preemption watchdog timer */ @@ -187,7 +161,8 @@ void a5xx_preempt_irq(struct msm_gpu *gpu) */ status = gpu_read(gpu, REG_A5XX_CP_CONTEXT_SWITCH_CNTL); if (unlikely(status)) { - set_preempt_state(a5xx_gpu, PREEMPT_FAULTED); + adreno_set_preempt_state(&a5xx_gpu->preempt_state, + PREEMPT_FAULTED); dev_err(dev->dev, "%s: Preemption failed to complete\n", gpu->name); queue_work(priv->wq, &gpu->recover_work); @@ -199,7 +174,7 @@ void a5xx_preempt_irq(struct msm_gpu *gpu)

update_wptr(gpu, a5xx_gpu->cur_ring);

- set_preempt_state(a5xx_gpu, PREEMPT_NONE); + adreno_set_preempt_state(&a5xx_gpu->preempt_state, PREEMPT_NONE); }

void a5xx_preempt_hw_init(struct msm_gpu *gpu) @@ -219,7 +194,7 @@ void a5xx_preempt_hw_init(struct msm_gpu *gpu) REG_A5XX_CP_CONTEXT_SWITCH_SMMU_INFO_HI, 0);

/* Reset the preemption state */ - set_preempt_state(a5xx_gpu, PREEMPT_NONE); + adreno_set_preempt_state(&a5xx_gpu->preempt_state, PREEMPT_NONE);

/* Always come up on rb 0 */ a5xx_gpu->cur_ring = gpu->rb[0]; diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h index aca1d7d..21ab701 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h @@ -54,32 +54,6 @@ struct a6xx_gpu { (a6xx_gpu->scratch_iova + (ring_id * sizeof(uint64_t)))

/* - * In order to do lockless preemption we use a simple state machine to progress - * through the process. - * - * PREEMPT_NONE - no preemption in progress. Next state START. - * PREEMPT_START - The trigger is evaluating if preemption is possible. Next - * states: TRIGGERED, NONE - * PREEMPT_ABORT - An intermediate state before moving back to NONE. Next - * state: NONE. - * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next - * states: FAULTED, PENDING - * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger - * recovery. Next state: N/A - * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is - * checking the success of the operation. Next state: FAULTED, NONE. - */ - -enum a6xx_preempt_state { - PREEMPT_NONE = 0, - PREEMPT_START, - PREEMPT_ABORT, - PREEMPT_TRIGGERED, - PREEMPT_FAULTED, - PREEMPT_PENDING, -}; - -/* * ID values used by SET_PSEUDO_REG PM4 command. These determine which of the * various internal CP registers to write to. Used in the save/restore * preemption sequence. diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c index 60df6c5..0d2b612 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c @@ -5,37 +5,6 @@ #include "a6xx_gpu.h" #include "a6xx_gmu.xml.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) { @@ -80,7 +49,8 @@ static void a6xx_preempt_timer(unsigned long data) struct drm_device *dev = gpu->dev; struct msm_drm_private *priv = dev->dev_private;

- if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED)) + if (!adreno_try_preempt_state(&a6xx_gpu->preempt_state, + PREEMPT_TRIGGERED, PREEMPT_FAULTED)) return;

dev_err(dev->dev, "%s: preemption timed out\n", gpu->name); @@ -95,7 +65,8 @@ void a6xx_preempt_irq(struct msm_gpu *gpu) struct drm_device *dev = gpu->dev; struct msm_drm_private *priv = dev->dev_private;

- if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING)) + if (!adreno_try_preempt_state(&a6xx_gpu->preempt_state, + PREEMPT_TRIGGERED, PREEMPT_PENDING)) return;

/* Delete the preemption watchdog timer */ @@ -110,7 +81,8 @@ void a6xx_preempt_irq(struct msm_gpu *gpu) */ status = gpu_read(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL); if (unlikely(status & 0x1)) { - set_preempt_state(a6xx_gpu, PREEMPT_FAULTED); + adreno_set_preempt_state(&a6xx_gpu->preempt_state, + PREEMPT_FAULTED); dev_err(dev->dev, "%s: Preemption failed to complete\n", gpu->name); queue_work(priv->wq, &gpu->recover_work); @@ -122,7 +94,7 @@ void a6xx_preempt_irq(struct msm_gpu *gpu)

update_wptr(gpu, a6xx_gpu->cur_ring);

- set_preempt_state(a6xx_gpu, PREEMPT_NONE); + adreno_set_preempt_state(&a6xx_gpu->preempt_state, PREEMPT_NONE); }

void a6xx_preempt_hw_init(struct msm_gpu *gpu) @@ -151,7 +123,7 @@ void a6xx_preempt_hw_init(struct msm_gpu *gpu) gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);

/* Reset the preemption state */ - set_preempt_state(a6xx_gpu, PREEMPT_NONE); + adreno_set_preempt_state(&a6xx_gpu->preempt_state, PREEMPT_NONE);

/* Always come up on rb 0 */ a6xx_gpu->cur_ring = gpu->rb[0]; @@ -175,7 +147,8 @@ void a6xx_preempt_trigger(struct msm_gpu *gpu) * 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)) + if (!adreno_try_preempt_state(&a6xx_gpu->preempt_state, + PREEMPT_NONE, PREEMPT_START)) return;

cntl = (((a6xx_gpu->preempt_level << 6) & 0xC0) | @@ -190,9 +163,11 @@ void a6xx_preempt_trigger(struct msm_gpu *gpu) * 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_ABORT); + adreno_set_preempt_state(&a6xx_gpu->preempt_state, + PREEMPT_ABORT); update_wptr(gpu, a6xx_gpu->cur_ring); - set_preempt_state(a6xx_gpu, PREEMPT_NONE); + adreno_set_preempt_state(&a6xx_gpu->preempt_state, + PREEMPT_NONE); return; }

@@ -243,7 +218,7 @@ void a6xx_preempt_trigger(struct msm_gpu *gpu) mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));

/* Set the preemption state to triggered */ - set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED); + adreno_set_preempt_state(&a6xx_gpu->preempt_state, PREEMPT_TRIGGERED);

/* Make sure everything is written before hitting the button */ wmb(); diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h index 94764d0..bb9affd 100644 --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h @@ -368,4 +368,58 @@ static inline uint32_t get_wptr(struct msm_ringbuffer *ring) ((1 << 29) \ ((ilog2((_len)) & 0x1F) << 24) | (((_reg) << 2) & 0xFFFFF))

+/* + * In order to do lockless preemption we use a simple state machine to progress + * through the process. + * + * PREEMPT_NONE - no preemption in progress. Next state START. + * PREEMPT_START - The trigger is evaluating if preemption is possible. Next + * states: TRIGGERED, NONE + * PREEMPT_ABORT - An intermediate state before moving back to NONE. Next + * state: NONE. + * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next + * states: FAULTED, PENDING + * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger + * recovery. Next state: N/A + * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is + * checking the success of the operation. Next state: FAULTED, NONE. + */ +enum adreno_preempt_state { + PREEMPT_NONE = 0, + PREEMPT_START, + PREEMPT_ABORT, + PREEMPT_TRIGGERED, + PREEMPT_FAULTED, + PREEMPT_PENDING, +}; + +/* + * 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 adreno_try_preempt_state(atomic_t *preempt_state, + enum adreno_preempt_state old, enum adreno_preempt_state new) +{ + enum adreno_preempt_state cur = atomic_cmpxchg(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 adreno_set_preempt_state(atomic_t *preempt_state, + enum adreno_preempt_state new) +{ + /* + * adreno_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(preempt_state, new); + /* ... and after*/ + smp_mb__after_atomic(); +} #endif /* __ADRENO_GPU_H__ */