[PATCH v8 06/12] drm/msm/a6xx: Implement preemption for a7xx targets
From: Antonino Maniscalco
Date: Thu Oct 03 2024 - 12:15:03 EST
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.
Reviewed-by: Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx>
Tested-by: Rob Clark <robdclark@xxxxxxxxx>
Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx> # on SM8650-QRD
Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx> # on SM8550-QRD
Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx> # on SM8450-HDK
Signed-off-by: Sharat Masetty <smasetty@xxxxxxxxxxxxxx>
Signed-off-by: Antonino Maniscalco <antomani103@xxxxxxxxx>
---
drivers/gpu/drm/msm/Makefile | 1 +
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 193 ++++++++++++++-
drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 162 ++++++++++++
drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 393 ++++++++++++++++++++++++++++++
drivers/gpu/drm/msm/msm_ringbuffer.h | 7 +
5 files changed, 745 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
index f5e2838c6a76505b353f83c9fe9c997f1c282701..32e915109a59dda96ed76ddd2b4f57bb225f4572 100644
--- a/drivers/gpu/drm/msm/Makefile
+++ b/drivers/gpu/drm/msm/Makefile
@@ -23,6 +23,7 @@ adreno-y := \
adreno/a6xx_gpu.o \
adreno/a6xx_gmu.o \
adreno/a6xx_hfi.o \
+ adreno/a6xx_preempt.o \
adreno-$(CONFIG_DEBUG_FS) += adreno/a5xx_debugfs.o \
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 6e065500b64d6d95599d89c33e6703c92f210047..b4cd562f1dd8660c77430e1aeac7e4b7af32bfc7 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -68,6 +68,8 @@ static void update_shadow_rptr(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;
@@ -81,12 +83,17 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
/* Make sure to wrap wptr if we need to */
wptr = get_wptr(ring);
- spin_unlock_irqrestore(&ring->preempt_lock, flags);
-
- /* Make sure everything is posted before making a decision */
- mb();
+ /* Update HW if this is the current ring and we are not in preempt*/
+ if (!a6xx_in_preempt(a6xx_gpu)) {
+ if (a6xx_gpu->cur_ring == ring)
+ gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
+ else
+ ring->restore_wptr = true;
+ } else {
+ ring->restore_wptr = true;
+ }
- gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
+ spin_unlock_irqrestore(&ring->preempt_lock, flags);
}
static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
@@ -138,12 +145,14 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
/*
* Write the new TTBR0 to the memstore. This is good for debugging.
+ * Needed for preemption
*/
- OUT_PKT7(ring, CP_MEM_WRITE, 4);
+ OUT_PKT7(ring, CP_MEM_WRITE, 5);
OUT_RING(ring, CP_MEM_WRITE_0_ADDR_LO(lower_32_bits(memptr)));
OUT_RING(ring, CP_MEM_WRITE_1_ADDR_HI(upper_32_bits(memptr)));
OUT_RING(ring, lower_32_bits(ttbr));
- OUT_RING(ring, (asid << 16) | upper_32_bits(ttbr));
+ OUT_RING(ring, upper_32_bits(ttbr));
+ OUT_RING(ring, ctx->seqno);
/*
* Sync both threads after switching pagetables and enable BR only
@@ -268,6 +277,34 @@ 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,
+ struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue)
+{
+ OUT_PKT7(ring, CP_SET_PSEUDO_REG, 12);
+
+ OUT_RING(ring, SMMU_INFO);
+ /* don't save SMMU, we write the record from the kernel instead */
+ OUT_RING(ring, 0);
+ OUT_RING(ring, 0);
+
+ /* privileged and non secure buffer save */
+ OUT_RING(ring, NON_SECURE_SAVE_ADDR);
+ 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, seems to be unnused by fw */
+ OUT_RING(ring, NON_PRIV_SAVE_ADDR);
+ OUT_RING(ring, 0);
+ OUT_RING(ring, 0);
+
+ OUT_RING(ring, COUNTER);
+ /* seems OK to set to 0 to disable it */
+ OUT_RING(ring, 0);
+ OUT_RING(ring, 0);
+}
+
static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
{
unsigned int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
@@ -285,6 +322,13 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
a6xx_set_pagetable(a6xx_gpu, ring, submit->queue->ctx);
+ /*
+ * If preemption is enabled, then set the pseudo register for the save
+ * sequence
+ */
+ if (gpu->nr_rings > 1)
+ a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, submit->queue);
+
get_stats_counter(ring, REG_A7XX_RBBM_PERFCTR_CP(0),
rbmemptr_stats(ring, index, cpcycles_start));
get_stats_counter(ring, REG_A6XX_CP_ALWAYS_ON_COUNTER,
@@ -376,6 +420,8 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
OUT_RING(ring, upper_32_bits(rbmemptr(ring, bv_fence)));
OUT_RING(ring, submit->seqno);
+ a6xx_gpu->last_seqno[ring->id] = submit->seqno;
+
/* write the ringbuffer timestamp */
OUT_PKT7(ring, CP_EVENT_WRITE, 4);
OUT_RING(ring, CACHE_CLEAN | CP_EVENT_WRITE_0_IRQ | BIT(27));
@@ -389,10 +435,32 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
OUT_PKT7(ring, CP_SET_MARKER, 1);
OUT_RING(ring, 0x100); /* IFPC enable */
+ /* If preemption is enabled */
+ if (gpu->nr_rings > 1) {
+ /* 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);
+ }
+
+
trace_msm_gpu_submit_flush(submit,
gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
a6xx_flush(gpu, ring);
+
+ /* Check to see if we need to start preemption */
+ a6xx_preempt_trigger(gpu);
}
static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
@@ -588,6 +656,77 @@ static void a6xx_set_ubwc_config(struct msm_gpu *gpu)
adreno_gpu->ubwc_config.min_acc_len << 23 | hbb_lo << 21);
}
+static void a7xx_patch_pwrup_reglist(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+ const struct adreno_reglist_list *reglist;
+ void *ptr = a6xx_gpu->pwrup_reglist_ptr;
+ struct cpu_gpu_lock *lock = ptr;
+ u32 *dest = (u32 *)&lock->regs[0];
+ int i;
+
+ reglist = adreno_gpu->info->a6xx->pwrup_reglist;
+
+ lock->gpu_req = lock->cpu_req = lock->turn = 0;
+ lock->ifpc_list_len = 0;
+ lock->preemption_list_len = reglist->count;
+
+ /*
+ * For each entry in each of the lists, write the offset and the current
+ * register value into the GPU buffer
+ */
+ for (i = 0; i < reglist->count; i++) {
+ *dest++ = reglist->regs[i];
+ *dest++ = gpu_read(gpu, reglist->regs[i]);
+ }
+
+ /*
+ * The overall register list is composed of
+ * 1. Static IFPC-only registers
+ * 2. Static IFPC + preemption registers
+ * 3. Dynamic IFPC + preemption registers (ex: perfcounter selects)
+ *
+ * The first two lists are static. Size of these lists are stored as
+ * number of pairs in ifpc_list_len and preemption_list_len
+ * respectively. With concurrent binning, Some of the perfcounter
+ * registers being virtualized, CP needs to know the pipe id to program
+ * the aperture inorder to restore the same. Thus, third list is a
+ * dynamic list with triplets as
+ * (<aperture, shifted 12 bits> <address> <data>), and the length is
+ * stored as number for triplets in dynamic_list_len.
+ */
+ lock->dynamic_list_len = 0;
+}
+
+static int a7xx_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 a6xx_idle(gpu, ring) ? 0 : -EINVAL;
+}
+
static int a6xx_cp_init(struct msm_gpu *gpu)
{
struct msm_ringbuffer *ring = gpu->rb[0];
@@ -619,6 +758,8 @@ static int a6xx_cp_init(struct msm_gpu *gpu)
static int a7xx_cp_init(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];
u32 mask;
@@ -656,11 +797,11 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
/* *Don't* send a power up reg list for concurrent binning (TODO) */
/* Lo address */
- OUT_RING(ring, 0x00000000);
+ OUT_RING(ring, lower_32_bits(a6xx_gpu->pwrup_reglist_iova));
/* Hi address */
- OUT_RING(ring, 0x00000000);
+ OUT_RING(ring, upper_32_bits(a6xx_gpu->pwrup_reglist_iova));
/* BIT(31) set => read the regs from the list */
- OUT_RING(ring, 0x00000000);
+ OUT_RING(ring, BIT(31));
a6xx_flush(gpu, ring);
return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
@@ -784,6 +925,16 @@ static int a6xx_ucode_load(struct msm_gpu *gpu)
msm_gem_object_set_name(a6xx_gpu->shadow_bo, "shadow");
}
+ a6xx_gpu->pwrup_reglist_ptr = msm_gem_kernel_new(gpu->dev, PAGE_SIZE,
+ MSM_BO_WC | MSM_BO_MAP_PRIV,
+ gpu->aspace, &a6xx_gpu->pwrup_reglist_bo,
+ &a6xx_gpu->pwrup_reglist_iova);
+
+ if (IS_ERR(a6xx_gpu->pwrup_reglist_ptr))
+ return PTR_ERR(a6xx_gpu->pwrup_reglist_ptr);
+
+ msm_gem_object_set_name(a6xx_gpu->pwrup_reglist_bo, "pwrup_reglist");
+
return 0;
}
@@ -1128,6 +1279,8 @@ static int hw_init(struct msm_gpu *gpu)
if (a6xx_gpu->shadow_bo) {
gpu_write64(gpu, REG_A6XX_CP_RB_RPTR_ADDR,
shadowptr(a6xx_gpu, gpu->rb[0]));
+ for (unsigned int i = 0; i < gpu->nr_rings; i++)
+ a6xx_gpu->shadow[i] = 0;
}
/* ..which means "always" on A7xx, also for BV shadow */
@@ -1136,6 +1289,8 @@ static int hw_init(struct msm_gpu *gpu)
rbmemptr(gpu->rb[0], bv_rptr));
}
+ a6xx_preempt_hw_init(gpu);
+
/* Always come up on rb 0 */
a6xx_gpu->cur_ring = gpu->rb[0];
@@ -1145,6 +1300,11 @@ static int hw_init(struct msm_gpu *gpu)
/* Enable the SQE_to start the CP engine */
gpu_write(gpu, REG_A6XX_CP_SQE_CNTL, 1);
+ if (adreno_is_a7xx(adreno_gpu) && !a6xx_gpu->pwrup_reglist_emitted) {
+ a7xx_patch_pwrup_reglist(gpu);
+ a6xx_gpu->pwrup_reglist_emitted = true;
+ }
+
ret = adreno_is_a7xx(adreno_gpu) ? a7xx_cp_init(gpu) : a6xx_cp_init(gpu);
if (ret)
goto out;
@@ -1182,6 +1342,10 @@ static int hw_init(struct msm_gpu *gpu)
out:
if (adreno_has_gmu_wrapper(adreno_gpu))
return ret;
+
+ /* Last step - yield the ringbuffer */
+ a7xx_preempt_start(gpu);
+
/*
* Tell the GMU that we are done touching the GPU and it can start power
* management
@@ -1559,8 +1723,13 @@ static irqreturn_t a6xx_irq(struct msm_gpu *gpu)
if (status & A6XX_RBBM_INT_0_MASK_SWFUSEVIOLATION)
a7xx_sw_fuse_violation_irq(gpu);
- 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;
}
@@ -2333,6 +2502,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
a6xx_fault_handler);
a6xx_calc_ubwc_config(adreno_gpu);
+ /* 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 2f5f307ac3b6845197b06ca3754abc88d698007c..070bce058d3ff92aa7452b697763a16ab7e2faee 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
@@ -12,6 +12,24 @@
extern bool hang_debug;
+struct cpu_gpu_lock {
+ uint32_t gpu_req;
+ uint32_t cpu_req;
+ uint32_t turn;
+ union {
+ struct {
+ uint16_t list_length;
+ uint16_t list_offset;
+ };
+ struct {
+ uint8_t ifpc_list_len;
+ uint8_t preemption_list_len;
+ uint16_t dynamic_list_len;
+ };
+ };
+ uint64_t regs[62];
+};
+
/**
* struct a6xx_info - a6xx specific information from device table
*
@@ -33,6 +51,23 @@ 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];
+ void *preempt[MSM_GPU_MAX_RINGS];
+ uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
+ struct drm_gem_object *preempt_smmu_bo[MSM_GPU_MAX_RINGS];
+ void *preempt_smmu[MSM_GPU_MAX_RINGS];
+ uint64_t preempt_smmu_iova[MSM_GPU_MAX_RINGS];
+ uint32_t last_seqno[MSM_GPU_MAX_RINGS];
+
+ atomic_t preempt_state;
+ spinlock_t eval_lock;
+ struct timer_list preempt_timer;
+
+ unsigned int preempt_level;
+ bool uses_gmem;
+ bool skip_save_restore;
struct a6xx_gmu gmu;
@@ -40,6 +75,11 @@ struct a6xx_gpu {
uint64_t shadow_iova;
uint32_t *shadow;
+ struct drm_gem_object *pwrup_reglist_bo;
+ void *pwrup_reglist_ptr;
+ uint64_t pwrup_reglist_iova;
+ bool pwrup_reglist_emitted;
+
bool has_whereami;
void __iomem *llc_mmio;
@@ -51,6 +91,100 @@ struct a6xx_gpu {
#define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
+/*
+ * 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_FINISH - 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_FINISH,
+ PREEMPT_TRIGGERED,
+ PREEMPT_FAULTED,
+ PREEMPT_PENDING,
+};
+
+/*
+ * 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
+ * @bv_rptr_addr: Value of BV_RB_RPTR_ADDR_LO|HI written by CPU, save/restored by CP
+ */
+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;
+ u64 bv_rptr_addr;
+};
+
+#define A6XX_PREEMPT_RECORD_MAGIC 0xAE399D6EUL
+
+#define PREEMPT_SMMU_INFO_SIZE 4096
+
+#define PREEMPT_RECORD_SIZE(adreno_gpu) \
+ ((adreno_gpu->info->preempt_record_size) == 0 ? \
+ 4192 * SZ_1K : (adreno_gpu->info->preempt_record_size))
+
+/*
+ * 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)
+
+struct a7xx_cp_smmu_info {
+ u32 magic;
+ u32 _pad4;
+ u64 ttbr0;
+ u32 asid;
+ u32 context_idr;
+ u32 context_bank;
+};
+
+#define GEN7_CP_SMMU_INFO_MAGIC 0x241350d5UL
+
/*
* 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
@@ -108,6 +242,34 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
int a6xx_gmu_wrapper_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu);
+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)
+{
+ /*
+ * Make sure the read to preempt_state is ordered with respect to reads
+ * of other variables before ...
+ */
+ smp_rmb();
+
+ int preempt_state = atomic_read(&a6xx_gpu->preempt_state);
+
+ /* ... and after. */
+ smp_rmb();
+
+ return !(preempt_state == PREEMPT_NONE ||
+ preempt_state == PREEMPT_FINISH);
+}
+
void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
bool suspended);
unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu);
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 0000000000000000000000000000000000000000..fd2a90360740591d45758f7311ec5cdda1855b20
--- /dev/null
+++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
@@ -0,0 +1,393 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */
+/* Copyright (c) 2023 Collabora, Ltd. */
+/* Copyright (c) 2024 Valve Corporation */
+
+#include "msm_gem.h"
+#include "a6xx_gpu.h"
+#include "a6xx_gmu.xml.h"
+#include "msm_mmu.h"
+
+/*
+ * Try to transition the preemption state from old to new. Return
+ * true on success or false if the original state wasn't 'old'
+ */
+static inline bool try_preempt_state(struct a6xx_gpu *a6xx_gpu,
+ enum a6xx_preempt_state old, enum a6xx_preempt_state new)
+{
+ enum a6xx_preempt_state cur = atomic_cmpxchg(&a6xx_gpu->preempt_state,
+ old, new);
+
+ return (cur == old);
+}
+
+/*
+ * Force the preemption state to the specified state. This is used in cases
+ * where the current state is known and won't change
+ */
+static inline void set_preempt_state(struct a6xx_gpu *gpu,
+ enum a6xx_preempt_state new)
+{
+ /*
+ * preempt_state may be read by other cores trying to trigger a
+ * preemption or in the interrupt handler so barriers are needed
+ * before...
+ */
+ smp_mb__before_atomic();
+ atomic_set(&gpu->preempt_state, new);
+ /* ... and after*/
+ smp_mb__after_atomic();
+}
+
+/* Write the most recent wptr for the given ring into the hardware */
+static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
+{
+ unsigned long flags;
+ uint32_t wptr;
+
+ spin_lock_irqsave(&ring->preempt_lock, flags);
+
+ if (ring->restore_wptr) {
+ wptr = get_wptr(ring);
+
+ gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
+
+ ring->restore_wptr = false;
+ }
+
+ spin_unlock_irqrestore(&ring->preempt_lock, flags);
+}
+
+/* Return the highest priority ringbuffer with something in it */
+static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+
+ unsigned long flags;
+ int i;
+
+ for (i = 0; i < gpu->nr_rings; i++) {
+ bool empty;
+ struct msm_ringbuffer *ring = gpu->rb[i];
+
+ spin_lock_irqsave(&ring->preempt_lock, flags);
+ empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
+ if (!empty && ring == a6xx_gpu->cur_ring)
+ empty = ring->memptrs->fence == a6xx_gpu->last_seqno[i];
+ spin_unlock_irqrestore(&ring->preempt_lock, flags);
+
+ if (!empty)
+ return ring;
+ }
+
+ return NULL;
+}
+
+static void a6xx_preempt_timer(struct timer_list *t)
+{
+ struct a6xx_gpu *a6xx_gpu = from_timer(a6xx_gpu, t, preempt_timer);
+ struct msm_gpu *gpu = &a6xx_gpu->base.base;
+ struct drm_device *dev = gpu->dev;
+
+ if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
+ return;
+
+ dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
+ kthread_queue_work(gpu->worker, &gpu->recover_work);
+}
+
+void a6xx_preempt_irq(struct msm_gpu *gpu)
+{
+ uint32_t status;
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+ struct drm_device *dev = gpu->dev;
+
+ if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
+ return;
+
+ /* Delete the preemption watchdog timer */
+ 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 & A6XX_CP_CONTEXT_SWITCH_CNTL_STOP)) {
+ DRM_DEV_ERROR(&gpu->pdev->dev,
+ "!!!!!!!!!!!!!!!! preemption faulted !!!!!!!!!!!!!! irq\n");
+ set_preempt_state(a6xx_gpu, PREEMPT_FAULTED);
+ dev_err(dev->dev, "%s: Preemption failed to complete\n",
+ gpu->name);
+ kthread_queue_work(gpu->worker, &gpu->recover_work);
+ return;
+ }
+
+ a6xx_gpu->cur_ring = a6xx_gpu->next_ring;
+ a6xx_gpu->next_ring = NULL;
+
+ set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
+
+ update_wptr(gpu, a6xx_gpu->cur_ring);
+
+ set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+
+ /*
+ * Retrigger preemption to avoid a deadlock that might occur when preemption
+ * is skipped due to it being already in flight when requested.
+ */
+ a6xx_preempt_trigger(gpu);
+}
+
+void a6xx_preempt_hw_init(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+ int i;
+
+ /* No preemption if we only have one ring */
+ if (gpu->nr_rings == 1)
+ return;
+
+ for (i = 0; i < gpu->nr_rings; i++) {
+ struct a6xx_preempt_record *record_ptr = a6xx_gpu->preempt[i];
+
+ record_ptr->wptr = 0;
+ record_ptr->rptr = 0;
+ record_ptr->rptr_addr = shadowptr(a6xx_gpu, gpu->rb[i]);
+ record_ptr->info = 0;
+ record_ptr->data = 0;
+ record_ptr->rbase = gpu->rb[i]->iova;
+ }
+
+ /* Write a 0 to signal that we aren't switching pagetables */
+ gpu_write64(gpu, REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO, 0);
+
+ /* Enable the GMEM save/restore feature for preemption */
+ gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);
+
+ /* Reset the preemption state */
+ set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+
+ spin_lock_init(&a6xx_gpu->eval_lock);
+
+ /* Always come up on rb 0 */
+ a6xx_gpu->cur_ring = gpu->rb[0];
+}
+
+void a6xx_preempt_trigger(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+ unsigned long flags;
+ struct msm_ringbuffer *ring;
+ unsigned int cntl;
+
+ if (gpu->nr_rings == 1)
+ return;
+
+ /*
+ * Lock to make sure another thread attempting preemption doesn't skip it
+ * while we are still evaluating the next ring. This makes sure the other
+ * thread does start preemption if we abort it and avoids a soft lock.
+ */
+ spin_lock_irqsave(&a6xx_gpu->eval_lock, flags);
+
+ /*
+ * Try to start preemption by moving from NONE to START. If
+ * unsuccessful, a preemption is already in flight
+ */
+ if (!try_preempt_state(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) {
+ spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
+ return;
+ }
+
+ cntl = A6XX_CP_CONTEXT_SWITCH_CNTL_LEVEL(a6xx_gpu->preempt_level);
+
+ if (a6xx_gpu->skip_save_restore)
+ cntl |= A6XX_CP_CONTEXT_SWITCH_CNTL_SKIP_SAVE_RESTORE;
+
+ if (a6xx_gpu->uses_gmem)
+ cntl |= A6XX_CP_CONTEXT_SWITCH_CNTL_USES_GMEM;
+
+ cntl |= A6XX_CP_CONTEXT_SWITCH_CNTL_STOP;
+
+ /* Get the next ring to preempt to */
+ ring = get_next_ring(gpu);
+
+ /*
+ * If no ring is populated or the highest priority ring is the current
+ * one do nothing except to update the wptr to the latest and greatest
+ */
+ if (!ring || (a6xx_gpu->cur_ring == ring)) {
+ set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
+ update_wptr(gpu, a6xx_gpu->cur_ring);
+ set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+ spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
+ return;
+ }
+
+ spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
+
+ spin_lock_irqsave(&ring->preempt_lock, flags);
+
+ struct a7xx_cp_smmu_info *smmu_info_ptr =
+ a6xx_gpu->preempt_smmu[ring->id];
+ struct a6xx_preempt_record *record_ptr = a6xx_gpu->preempt[ring->id];
+ u64 ttbr0 = ring->memptrs->ttbr0;
+ u32 context_idr = ring->memptrs->context_idr;
+
+ smmu_info_ptr->ttbr0 = ttbr0;
+ smmu_info_ptr->context_idr = context_idr;
+ record_ptr->wptr = get_wptr(ring);
+
+ /*
+ * The GPU will write the wptr we set above when we preempt. Reset
+ * restore_wptr to make sure that we don't write WPTR to the same
+ * thing twice. It's still possible subsequent submissions will update
+ * wptr again, in which case they will set the flag to true. This has
+ * to be protected by the lock for setting the flag and updating wptr
+ * to be atomic.
+ */
+ ring->restore_wptr = false;
+
+ spin_unlock_irqrestore(&ring->preempt_lock, flags);
+
+ gpu_write64(gpu,
+ REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO,
+ a6xx_gpu->preempt_smmu_iova[ring->id]);
+
+ gpu_write64(gpu,
+ REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
+ a6xx_gpu->preempt_iova[ring->id]);
+
+ a6xx_gpu->next_ring = ring;
+
+ /* Start a timer to catch a stuck preemption */
+ mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
+
+ /* Set the preemption state to triggered */
+ set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED);
+
+ /* Trigger the preemption */
+ gpu_write(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl);
+}
+
+static int preempt_init_ring(struct a6xx_gpu *a6xx_gpu,
+ struct msm_ringbuffer *ring)
+{
+ struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
+ struct msm_gpu *gpu = &adreno_gpu->base;
+ struct drm_gem_object *bo = NULL;
+ phys_addr_t ttbr;
+ u64 iova = 0;
+ void *ptr;
+ int asid;
+
+ ptr = msm_gem_kernel_new(gpu->dev,
+ PREEMPT_RECORD_SIZE(adreno_gpu),
+ MSM_BO_WC | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
+
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+
+ memset(ptr, 0, PREEMPT_RECORD_SIZE(adreno_gpu));
+
+ msm_gem_object_set_name(bo, "preempt_record ring%d", ring->id);
+
+ a6xx_gpu->preempt_bo[ring->id] = bo;
+ a6xx_gpu->preempt_iova[ring->id] = iova;
+ a6xx_gpu->preempt[ring->id] = ptr;
+
+ struct a6xx_preempt_record *record_ptr = ptr;
+
+ ptr = msm_gem_kernel_new(gpu->dev,
+ PREEMPT_SMMU_INFO_SIZE,
+ MSM_BO_WC | MSM_BO_MAP_PRIV | MSM_BO_GPU_READONLY,
+ gpu->aspace, &bo, &iova);
+
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+
+ memset(ptr, 0, PREEMPT_SMMU_INFO_SIZE);
+
+ msm_gem_object_set_name(bo, "preempt_smmu_info ring%d", ring->id);
+
+ a6xx_gpu->preempt_smmu_bo[ring->id] = bo;
+ a6xx_gpu->preempt_smmu_iova[ring->id] = iova;
+ a6xx_gpu->preempt_smmu[ring->id] = ptr;
+
+ struct a7xx_cp_smmu_info *smmu_info_ptr = ptr;
+
+ msm_iommu_pagetable_params(gpu->aspace->mmu, &ttbr, &asid);
+
+ smmu_info_ptr->magic = GEN7_CP_SMMU_INFO_MAGIC;
+ smmu_info_ptr->ttbr0 = ttbr;
+ smmu_info_ptr->asid = 0xdecafbad;
+ smmu_info_ptr->context_idr = 0;
+
+ /* Set up the defaults on the preemption record */
+ record_ptr->magic = A6XX_PREEMPT_RECORD_MAGIC;
+ record_ptr->info = 0;
+ record_ptr->data = 0;
+ record_ptr->rptr = 0;
+ record_ptr->wptr = 0;
+ record_ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
+ record_ptr->rbase = ring->iova;
+ record_ptr->counter = 0;
+ record_ptr->bv_rptr_addr = rbmemptr(ring, bv_rptr);
+
+ return 0;
+}
+
+void a6xx_preempt_fini(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+ int i;
+
+ for (i = 0; i < gpu->nr_rings; i++)
+ msm_gem_kernel_put(a6xx_gpu->preempt_bo[i], gpu->aspace);
+}
+
+void a6xx_preempt_init(struct msm_gpu *gpu)
+{
+ struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+ struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+ int i;
+
+ /* No preemption if we only have one ring */
+ if (gpu->nr_rings <= 1)
+ return;
+
+ for (i = 0; i < gpu->nr_rings; i++) {
+ if (preempt_init_ring(a6xx_gpu, gpu->rb[i]))
+ goto fail;
+ }
+
+ /* TODO: make this configurable? */
+ a6xx_gpu->preempt_level = 1;
+ a6xx_gpu->uses_gmem = 1;
+ a6xx_gpu->skip_save_restore = 1;
+
+ timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
+
+ return;
+fail:
+ /*
+ * On any failure our adventure is over. Clean up and
+ * set nr_rings to 1 to force preemption off
+ */
+ a6xx_preempt_fini(gpu);
+ gpu->nr_rings = 1;
+
+ DRM_DEV_ERROR(&gpu->pdev->dev,
+ "preemption init failed, disabling preemption\n");
+
+ return;
+}
diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
index 174f83137a49940ec80b1fbf548e214fa3c32784..d1e49f701c8176e50d2b9a5cca35acee67f75209 100644
--- a/drivers/gpu/drm/msm/msm_ringbuffer.h
+++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
@@ -36,6 +36,7 @@ struct msm_rbmemptrs {
volatile struct msm_gpu_submit_stats stats[MSM_GPU_SUBMIT_STATS_COUNT];
volatile u64 ttbr0;
+ volatile u32 context_idr;
};
struct msm_cp_state {
@@ -101,6 +102,12 @@ struct msm_ringbuffer {
*/
spinlock_t preempt_lock;
+ /*
+ * Whether we skipped writing wptr and it needs to be updated in the
+ * future when the ring becomes current.
+ */
+ bool restore_wptr;
+
/**
* cur_ctx_seqno:
*
--
2.46.1