[PATCH 4/4] drm/amdgpu: busywait KIQ register accessing
Liu, Monk
Monk.Liu at amd.com
Fri Oct 13 09:34:38 UTC 2017
Pixel
I don't think this will work well, my suggestion is you add a new function like:
amdgpu_wreg_kiq_busy(),
which will write registers through KIQ and use polling/busy wait, and the original amdgu_wreg_no_kiq() can be still there.
When you need to disable sleep like in IRQ CONTEXT, you can call wreg_kiq_busy() or wreg_no_kiq(),
But don't just change the original function
BR Monk
-----Original Message-----
From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf Of Pixel Ding
Sent: 2017年10月13日 16:26
To: amd-gfx at lists.freedesktop.org
Cc: Ding, Pixel <Pixel.Ding at amd.com>; Li, Bingley <Bingley.Li at amd.com>
Subject: [PATCH 4/4] drm/amdgpu: busywait KIQ register accessing
From: pding <Pixel.Ding at amd.com>
Register accessing is performed when IRQ is disabled. Never sleep in this function.
Known issue: dead sleep in many use cases of index/data registers.
Signed-off-by: pding <Pixel.Ding at amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 8 ++--- drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 2 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c | 55 ++++++++++++++++++------------
6 files changed, 40 insertions(+), 28 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index ca212ef..f9de756 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -886,6 +886,7 @@ struct amdgpu_kiq {
u64 eop_gpu_addr;
struct amdgpu_bo *eop_obj;
struct mutex ring_mutex;
+ spinlock_t ring_lock;
struct amdgpu_ring ring;
struct amdgpu_irq_src irq;
};
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index ab8f0d6..1197274 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -109,10 +109,8 @@ uint32_t amdgpu_mm_rreg(struct amdgpu_device *adev, uint32_t reg, {
uint32_t ret;
- if (!(acc_flags & AMDGPU_REGS_NO_KIQ) && amdgpu_sriov_runtime(adev)) {
- BUG_ON(in_interrupt());
+ if (!(acc_flags & AMDGPU_REGS_NO_KIQ) && amdgpu_sriov_runtime(adev))
return amdgpu_virt_kiq_rreg(adev, reg);
- }
if ((reg * 4) < adev->rmmio_size && !(acc_flags & AMDGPU_REGS_IDX))
ret = readl(((void __iomem *)adev->rmmio) + (reg * 4)); @@ -137,10 +135,8 @@ void amdgpu_mm_wreg(struct amdgpu_device *adev, uint32_t reg, uint32_t v,
adev->last_mm_index = v;
}
- if (!(acc_flags & AMDGPU_REGS_NO_KIQ) && amdgpu_sriov_runtime(adev)) {
- BUG_ON(in_interrupt());
+ if (!(acc_flags & AMDGPU_REGS_NO_KIQ) && amdgpu_sriov_runtime(adev))
return amdgpu_virt_kiq_wreg(adev, reg, v);
- }
if ((reg * 4) < adev->rmmio_size && !(acc_flags & AMDGPU_REGS_IDX))
writel(v, ((void __iomem *)adev->rmmio) + (reg * 4)); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
index 2044758..c6c7bf3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -109,7 +109,7 @@ static void amdgpu_fence_write(struct amdgpu_ring *ring, u32 seq)
* Reads a fence value from memory (all asics).
* Returns the value of the fence read from memory.
*/
-static u32 amdgpu_fence_read(struct amdgpu_ring *ring)
+u32 amdgpu_fence_read(struct amdgpu_ring *ring)
{
struct amdgpu_fence_driver *drv = &ring->fence_drv;
u32 seq = 0;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
index 4f6c68f..46fa88c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
@@ -186,6 +186,7 @@ int amdgpu_gfx_kiq_init_ring(struct amdgpu_device *adev,
int r = 0;
mutex_init(&kiq->ring_mutex);
+ spin_lock_init(&kiq->ring_lock);
r = amdgpu_wb_get(adev, &adev->virt.reg_val_offs);
if (r)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
index af8e544..a4fa923 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
@@ -89,6 +89,7 @@ int amdgpu_fence_driver_start_ring(struct amdgpu_ring *ring, void amdgpu_fence_driver_suspend(struct amdgpu_device *adev); void amdgpu_fence_driver_resume(struct amdgpu_device *adev); int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **fence);
+u32 amdgpu_fence_read(struct amdgpu_ring *ring);
void amdgpu_fence_process(struct amdgpu_ring *ring); int amdgpu_fence_wait_empty(struct amdgpu_ring *ring); unsigned amdgpu_fence_count_emitted(struct amdgpu_ring *ring); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
index ab05121..9757df1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
@@ -22,7 +22,7 @@
*/
#include "amdgpu.h"
-#define MAX_KIQ_REG_WAIT 100000
+#define MAX_KIQ_REG_WAIT 100000000 /* in usecs */
int amdgpu_allocate_static_csa(struct amdgpu_device *adev) { @@ -113,28 +113,32 @@ void amdgpu_virt_init_setting(struct amdgpu_device *adev)
uint32_t amdgpu_virt_kiq_rreg(struct amdgpu_device *adev, uint32_t reg) {
- signed long r;
- uint32_t val;
- struct dma_fence *f;
+ signed long timeout = usecs_to_jiffies(MAX_KIQ_REG_WAIT);
+ unsigned long flags;
+ uint32_t val, seq, wait_seq;
struct amdgpu_kiq *kiq = &adev->gfx.kiq;
struct amdgpu_ring *ring = &kiq->ring;
BUG_ON(!ring->funcs->emit_rreg);
- mutex_lock(&kiq->ring_mutex);
+ spin_lock_irqsave(&kiq->ring_lock, flags);
amdgpu_ring_alloc(ring, 32);
amdgpu_ring_emit_rreg(ring, reg);
- amdgpu_fence_emit(ring, &f);
+ wait_seq = ++ring->fence_drv.sync_seq;
+ amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
+ wait_seq, AMDGPU_FENCE_FLAG_INT);
amdgpu_ring_commit(ring);
- mutex_unlock(&kiq->ring_mutex);
-
- r = dma_fence_wait_timeout(f, false, msecs_to_jiffies(MAX_KIQ_REG_WAIT));
- dma_fence_put(f);
- if (r < 1) {
- DRM_ERROR("wait for kiq fence error: %ld.\n", r);
+ spin_unlock_irqrestore(&kiq->ring_lock, flags);
+ do {
+ seq = amdgpu_fence_read(ring);
+ udelay(5);
+ timeout -= 5;
+ } while (seq < wait_seq && timeout > 0);
+
+ if (timeout < 1) {
+ DRM_ERROR("wait for kiq fence error: %ld\n", timeout);
return ~0;
}
-
val = adev->wb.wb[adev->virt.reg_val_offs];
return val;
@@ -142,24 +146,33 @@ uint32_t amdgpu_virt_kiq_rreg(struct amdgpu_device *adev, uint32_t reg)
void amdgpu_virt_kiq_wreg(struct amdgpu_device *adev, uint32_t reg, uint32_t v) {
- signed long r;
+ signed long timeout = usecs_to_jiffies(MAX_KIQ_REG_WAIT);
+ unsigned long flags;
+ uint32_t seq, wait_seq;
struct dma_fence *f;
struct amdgpu_kiq *kiq = &adev->gfx.kiq;
struct amdgpu_ring *ring = &kiq->ring;
BUG_ON(!ring->funcs->emit_wreg);
- mutex_lock(&kiq->ring_mutex);
+ spin_lock_irqsave(&kiq->ring_lock, flags);
amdgpu_ring_alloc(ring, 32);
amdgpu_ring_emit_wreg(ring, reg, v);
- amdgpu_fence_emit(ring, &f);
+ /* amdgpu_fence_emit(ring, &f); */
+ wait_seq = ++ring->fence_drv.sync_seq;
+ amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
+ wait_seq, AMDGPU_FENCE_FLAG_INT);
amdgpu_ring_commit(ring);
- mutex_unlock(&kiq->ring_mutex);
+ spin_unlock_irqrestore(&kiq->ring_lock, flags);
+
+ do {
+ seq = amdgpu_fence_read(ring);
+ udelay(5);
+ timeout -= 5;
+ } while (seq < wait_seq && timeout > 0);
- r = dma_fence_wait_timeout(f, false, msecs_to_jiffies(MAX_KIQ_REG_WAIT));
- if (r < 1)
- DRM_ERROR("wait for kiq fence error: %ld.\n", r);
- dma_fence_put(f);
+ if (timeout < 1)
+ DRM_ERROR("wait for kiq fence error: %ld\n", timeout);
}
/**
--
2.9.5
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