[PATCH 3/4] drm/msm/A6xx: Implement preemption for A6XX targets
Sharat Masetty
smasetty at codeaurora.org
Mon Feb 26 07:38:22 UTC 2018
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 at 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;
+}
--
1.9.1
More information about the dri-devel
mailing list