drm/radeon/kms: enable writeback (v2)

When writeback is enabled, the GPU shadows writes to certain
registers into a buffer in memory.  The driver can then read
the values from the shadow rather than reading back from the
register across the bus.  Writeback can be disabled by setting
the no_wb module param to 1.

On r6xx/r7xx/evergreen, the following registers are shadowed:
- CP scratch registers
- CP read pointer
- IH write pointer
On r1xx-rr5xx, the following registers are shadowed:
- CP scratch registers
- CP read pointer

v2:
- Combine wb patches for r6xx-evergreen and r1xx-r5xx
- Writeback is disabled on AGP boards since it tends to be
unreliable on AGP using the gart.
- Check radeon_wb_init return values properly.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 37 insertions, 79 deletions

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index 927509ff349a..fbce58b2cd04 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -1918,6 +1918,7 @@ void r600_pciep_wreg(struct radeon_device *rdev, u32 reg, u32 v)
 void r600_cp_stop(struct radeon_device *rdev)
 {
         WREG32(R_0086D8_CP_ME_CNTL, S_0086D8_CP_ME_HALT(1));
+        WREG32(SCRATCH_UMSK, 0);
 }
 
 int r600_init_microcode(struct radeon_device *rdev)
@@ -2150,7 +2151,7 @@ int r600_cp_resume(struct radeon_device *rdev)
 
         /* Set ring buffer size */
         rb_bufsz = drm_order(rdev->cp.ring_size / 8);
-        tmp = RB_NO_UPDATE | (drm_order(RADEON_GPU_PAGE_SIZE/8) << 8) | rb_bufsz;
+        tmp = (drm_order(RADEON_GPU_PAGE_SIZE/8) << 8) | rb_bufsz;
 #ifdef __BIG_ENDIAN
         tmp |= BUF_SWAP_32BIT;
 #endif
@@ -2164,8 +2165,19 @@ int r600_cp_resume(struct radeon_device *rdev)
         WREG32(CP_RB_CNTL, tmp | RB_RPTR_WR_ENA);
         WREG32(CP_RB_RPTR_WR, 0);
         WREG32(CP_RB_WPTR, 0);
-        WREG32(CP_RB_RPTR_ADDR, rdev->cp.gpu_addr & 0xFFFFFFFF);
-        WREG32(CP_RB_RPTR_ADDR_HI, upper_32_bits(rdev->cp.gpu_addr));
+
+        /* set the wb address whether it's enabled or not */
+        WREG32(CP_RB_RPTR_ADDR, (rdev->wb.gpu_addr + RADEON_WB_CP_RPTR_OFFSET) & 0xFFFFFFFC);
+        WREG32(CP_RB_RPTR_ADDR_HI, upper_32_bits(rdev->wb.gpu_addr + RADEON_WB_CP_RPTR_OFFSET) & 0xFF);
+        WREG32(SCRATCH_ADDR, ((rdev->wb.gpu_addr + RADEON_WB_SCRATCH_OFFSET) >> 8) & 0xFFFFFFFF);
+
+        if (rdev->wb.enabled)
+                WREG32(SCRATCH_UMSK, 0xff);
+        else {
+                tmp |= RB_NO_UPDATE;
+                WREG32(SCRATCH_UMSK, 0);
+        }
+
         mdelay(1);
         WREG32(CP_RB_CNTL, tmp);
 
@@ -2217,9 +2229,10 @@ void r600_scratch_init(struct radeon_device *rdev)
         int i;
 
         rdev->scratch.num_reg = 7;
+        rdev->scratch.reg_base = SCRATCH_REG0;
         for (i = 0; i < rdev->scratch.num_reg; i++) {
                 rdev->scratch.free[i] = true;
-                rdev->scratch.reg[i] = SCRATCH_REG0 + (i * 4);
+                rdev->scratch.reg[i] = rdev->scratch.reg_base + (i * 4);
         }
 }
 
@@ -2263,70 +2276,6 @@ int r600_ring_test(struct radeon_device *rdev)
         return r;
 }
 
-void r600_wb_disable(struct radeon_device *rdev)
-{
-        int r;
-
-        WREG32(SCRATCH_UMSK, 0);
-        if (rdev->wb.wb_obj) {
-                r = radeon_bo_reserve(rdev->wb.wb_obj, false);
-                if (unlikely(r != 0))
-                        return;
-                radeon_bo_kunmap(rdev->wb.wb_obj);
-                radeon_bo_unpin(rdev->wb.wb_obj);
-                radeon_bo_unreserve(rdev->wb.wb_obj);
-        }
-}
-
-void r600_wb_fini(struct radeon_device *rdev)
-{
-        r600_wb_disable(rdev);
-        if (rdev->wb.wb_obj) {
-                radeon_bo_unref(&rdev->wb.wb_obj);
-                rdev->wb.wb = NULL;
-                rdev->wb.wb_obj = NULL;
-        }
-}
-
-int r600_wb_enable(struct radeon_device *rdev)
-{
-        int r;
-
-        if (rdev->wb.wb_obj == NULL) {
-                r = radeon_bo_create(rdev, NULL, RADEON_GPU_PAGE_SIZE, true,
-                                RADEON_GEM_DOMAIN_GTT, &rdev->wb.wb_obj);
-                if (r) {
-                        dev_warn(rdev->dev, "(%d) create WB bo failed\n", r);
-                        return r;
-                }
-                r = radeon_bo_reserve(rdev->wb.wb_obj, false);
-                if (unlikely(r != 0)) {
-                        r600_wb_fini(rdev);
-                        return r;
-                }
-                r = radeon_bo_pin(rdev->wb.wb_obj, RADEON_GEM_DOMAIN_GTT,
-                                &rdev->wb.gpu_addr);
-                if (r) {
-                        radeon_bo_unreserve(rdev->wb.wb_obj);
-                        dev_warn(rdev->dev, "(%d) pin WB bo failed\n", r);
-                        r600_wb_fini(rdev);
-                        return r;
-                }
-                r = radeon_bo_kmap(rdev->wb.wb_obj, (void **)&rdev->wb.wb);
-                radeon_bo_unreserve(rdev->wb.wb_obj);
-                if (r) {
-                        dev_warn(rdev->dev, "(%d) map WB bo failed\n", r);
-                        r600_wb_fini(rdev);
-                        return r;
-                }
-        }
-        WREG32(SCRATCH_ADDR, (rdev->wb.gpu_addr >> 8) & 0xFFFFFFFF);
-        WREG32(CP_RB_RPTR_ADDR, (rdev->wb.gpu_addr + 1024) & 0xFFFFFFFC);
-        WREG32(CP_RB_RPTR_ADDR_HI, upper_32_bits(rdev->wb.gpu_addr + 1024) & 0xFF);
-        WREG32(SCRATCH_UMSK, 0xff);
-        return 0;
-}
-
 void r600_fence_ring_emit(struct radeon_device *rdev,
                           struct radeon_fence *fence)
 {
@@ -2427,6 +2376,11 @@ int r600_startup(struct radeon_device *rdev)
                 dev_warn(rdev->dev, "failed blitter (%d) falling back to memcpy\n", r);
         }
 
+        /* allocate wb buffer */
+        r = radeon_wb_init(rdev);
+        if (r)
+                return r;
+
         /* Enable IRQ */
         r = r600_irq_init(rdev);
         if (r) {
@@ -2445,8 +2399,7 @@ int r600_startup(struct radeon_device *rdev)
         r = r600_cp_resume(rdev);
         if (r)
                 return r;
-        /* write back buffer are not vital so don't worry about failure */
-        r600_wb_enable(rdev);
+
         return 0;
 }
 
@@ -2505,7 +2458,7 @@ int r600_suspend(struct radeon_device *rdev)
         r600_cp_stop(rdev);
         rdev->cp.ready = false;
         r600_irq_suspend(rdev);
-        r600_wb_disable(rdev);
+        radeon_wb_disable(rdev);
         r600_pcie_gart_disable(rdev);
         /* unpin shaders bo */
         if (rdev->r600_blit.shader_obj) {
@@ -2602,8 +2555,8 @@ int r600_init(struct radeon_device *rdev)
         if (r) {
                 dev_err(rdev->dev, "disabling GPU acceleration\n");
                 r600_cp_fini(rdev);
-                r600_wb_fini(rdev);
                 r600_irq_fini(rdev);
+                radeon_wb_fini(rdev);
                 radeon_irq_kms_fini(rdev);
                 r600_pcie_gart_fini(rdev);
                 rdev->accel_working = false;
@@ -2633,8 +2586,8 @@ void r600_fini(struct radeon_device *rdev)
         r600_audio_fini(rdev);
         r600_blit_fini(rdev);
         r600_cp_fini(rdev);
-        r600_wb_fini(rdev);
         r600_irq_fini(rdev);
+        radeon_wb_fini(rdev);
         radeon_irq_kms_fini(rdev);
         r600_pcie_gart_fini(rdev);
         radeon_agp_fini(rdev);
@@ -2969,10 +2922,13 @@ int r600_irq_init(struct radeon_device *rdev)
         ih_rb_cntl = (IH_WPTR_OVERFLOW_ENABLE |
                       IH_WPTR_OVERFLOW_CLEAR |
                       (rb_bufsz << 1));
-        /* WPTR writeback, not yet */
-        /*ih_rb_cntl |= IH_WPTR_WRITEBACK_ENABLE;*/
-        WREG32(IH_RB_WPTR_ADDR_LO, 0);
-        WREG32(IH_RB_WPTR_ADDR_HI, 0);
+
+        if (rdev->wb.enabled)
+                ih_rb_cntl |= IH_WPTR_WRITEBACK_ENABLE;
+
+        /* set the writeback address whether it's enabled or not */
+        WREG32(IH_RB_WPTR_ADDR_LO, (rdev->wb.gpu_addr + R600_WB_IH_WPTR_OFFSET) & 0xFFFFFFFC);
+        WREG32(IH_RB_WPTR_ADDR_HI, upper_32_bits(rdev->wb.gpu_addr + R600_WB_IH_WPTR_OFFSET) & 0xFF);
 
         WREG32(IH_RB_CNTL, ih_rb_cntl);
 
@@ -3230,8 +3186,10 @@ static inline u32 r600_get_ih_wptr(struct radeon_device *rdev)
 {
         u32 wptr, tmp;
 
-        /* XXX use writeback */
-        wptr = RREG32(IH_RB_WPTR);
+        if (rdev->wb.enabled)
+                wptr = rdev->wb.wb[R600_WB_IH_WPTR_OFFSET/4];
+        else
+                wptr = RREG32(IH_RB_WPTR);
 
         if (wptr & RB_OVERFLOW) {
                 /* When a ring buffer overflow happen start parsing interrupt