[PATCH v2 2/2] drm/amdgpu: use kiq to do invalidate tlb

[Emily Deng]

To avoid the tlb flush not interrupted by world switch, use kiq and one
command to do tlb invalidate.

v2:
Refine the invalidate lock position.

Signed-off-by: Emily Deng <Emily.Deng at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h      |  4 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c |  3 --
 drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c    | 74 +++++++++++++++++++++++++++++---
 3 files changed, 71 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 6265b88..19ef7711 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -212,6 +212,10 @@ enum amdgpu_kiq_irq {
 	AMDGPU_CP_KIQ_IRQ_LAST
 };
 
+#define MAX_KIQ_REG_WAIT       5000 /* in usecs, 5ms */
+#define MAX_KIQ_REG_BAILOUT_INTERVAL   5 /* in msecs, 5ms */
+#define MAX_KIQ_REG_TRY 20
+
 int amdgpu_device_ip_set_clockgating_state(void *dev,
 					   enum amd_ip_block_type block_type,
 					   enum amd_clockgating_state state);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
index 21adb1b6..3885636 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
@@ -22,9 +22,6 @@
  */
 
 #include "amdgpu.h"
-#define MAX_KIQ_REG_WAIT	5000 /* in usecs, 5ms */
-#define MAX_KIQ_REG_BAILOUT_INTERVAL	5 /* in msecs, 5ms */
-#define MAX_KIQ_REG_TRY 20
 
 uint64_t amdgpu_csa_vaddr(struct amdgpu_device *adev)
 {
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
index ed467de..0bf8439 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -311,6 +311,58 @@ static uint32_t gmc_v9_0_get_invalidate_req(unsigned int vmid)
 	return req;
 }
 
+signed long  amdgpu_kiq_reg_write_reg_wait(struct amdgpu_device *adev,
+						  uint32_t reg0, uint32_t reg1,
+						  uint32_t ref, uint32_t mask)
+{
+	signed long r, cnt = 0;
+	unsigned long flags;
+	uint32_t seq;
+	struct amdgpu_kiq *kiq = &adev->gfx.kiq;
+	struct amdgpu_ring *ring = &kiq->ring;
+
+	if (!ring->ready)
+		return -EINVAL;
+
+	spin_lock_irqsave(&kiq->ring_lock, flags);
+
+	amdgpu_ring_alloc(ring, 32);
+	amdgpu_ring_emit_reg_write_reg_wait(ring, reg0, reg1,
+					    ref, mask);
+	amdgpu_fence_emit_polling(ring, &seq);
+	amdgpu_ring_commit(ring);
+	spin_unlock_irqrestore(&kiq->ring_lock, flags);
+
+	r = amdgpu_fence_wait_polling(ring, seq, MAX_KIQ_REG_WAIT);
+
+	/* don't wait anymore for gpu reset case because this way may
+	 * block gpu_recover() routine forever, e.g. this virt_kiq_rreg
+	 * is triggered in TTM and ttm_bo_lock_delayed_workqueue() will
+	 * never return if we keep waiting in virt_kiq_rreg, which cause
+	 * gpu_recover() hang there.
+	 *
+	 * also don't wait anymore for IRQ context
+	 * */
+	if (r < 1 && (adev->in_gpu_reset || in_interrupt()))
+		goto failed_kiq;
+
+	might_sleep();
+
+	while (r < 1 && cnt++ < MAX_KIQ_REG_TRY) {
+		msleep(MAX_KIQ_REG_BAILOUT_INTERVAL);
+		r = amdgpu_fence_wait_polling(ring, seq, MAX_KIQ_REG_WAIT);
+	}
+
+	if (cnt > MAX_KIQ_REG_TRY)
+		goto failed_kiq;
+
+	return 0;
+
+failed_kiq:
+	pr_err("failed to invalidate tlb with kiq\n");
+	return r;
+}
+
 /*
  * GART
  * VMID 0 is the physical GPU addresses as used by the kernel.
@@ -332,13 +384,19 @@ static void gmc_v9_0_flush_gpu_tlb(struct amdgpu_device *adev,
 	/* Use register 17 for GART */
 	const unsigned eng = 17;
 	unsigned i, j;
-
-	spin_lock(&adev->gmc.invalidate_lock);
+	int r;
 
 	for (i = 0; i < AMDGPU_MAX_VMHUBS; ++i) {
 		struct amdgpu_vmhub *hub = &adev->vmhub[i];
 		u32 tmp = gmc_v9_0_get_invalidate_req(vmid);
 
+		r = amdgpu_kiq_reg_write_reg_wait(adev, hub->vm_inv_eng0_req + eng,
+			hub->vm_inv_eng0_ack + eng, tmp, 1 << vmid);
+		if (!r)
+			continue;
+
+		spin_lock(&adev->gmc.invalidate_lock);
+
 		WREG32_NO_KIQ(hub->vm_inv_eng0_req + eng, tmp);
 
 		/* Busy wait for ACK.*/
@@ -349,8 +407,10 @@ static void gmc_v9_0_flush_gpu_tlb(struct amdgpu_device *adev,
 				break;
 			cpu_relax();
 		}
-		if (j < 100)
+		if (j < 100) {
+			spin_unlock(&adev->gmc.invalidate_lock);
 			continue;
+		}
 
 		/* Wait for ACK with a delay.*/
 		for (j = 0; j < adev->usec_timeout; j++) {
@@ -360,13 +420,13 @@ static void gmc_v9_0_flush_gpu_tlb(struct amdgpu_device *adev,
 				break;
 			udelay(1);
 		}
-		if (j < adev->usec_timeout)
+		if (j < adev->usec_timeout) {
+			spin_unlock(&adev->gmc.invalidate_lock);
 			continue;
-
+		}
+		spin_unlock(&adev->gmc.invalidate_lock);
 		DRM_ERROR("Timeout waiting for VM flush ACK!\n");
 	}
-
-	spin_unlock(&adev->gmc.invalidate_lock);
 }
 
 static uint64_t gmc_v9_0_emit_flush_gpu_tlb(struct amdgpu_ring *ring,
-- 
2.7.4