drm/radeon/kms: Workaround RV410/R420 CP errata (V3)

Long story short, this fixes sporadic hardlocks with my rv410 during
times of intense 2D acceleration (Flash on Fx3).

V2: Fix indentation and move errata_fini to suspend function so we
don't leak scratch register over suspend/resume cycle.
V3: Move scratch_reg to asic specific structure (aim is to slowly
    move stuff to asic specific structure and avoid poluting
    radeon_device struct with asic specific variables)

Signed-off-by: Corbin Simpson <MostAwesomeDude@gmail.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 32 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/r420.c b/drivers/gpu/drm/radeon/r420.c
index c05a7270cf0c..f46502a253ec 100644
--- a/drivers/gpu/drm/radeon/r420.c
+++ b/drivers/gpu/drm/radeon/r420.c
@@ -30,6 +30,7 @@
 #include "radeon_reg.h"
 #include "radeon.h"
 #include "atom.h"
+#include "r100d.h"
 #include "r420d.h"
 
 int r420_mc_init(struct radeon_device *rdev)
@@ -165,6 +166,34 @@ static void r420_clock_resume(struct radeon_device *rdev)
         WREG32_PLL(R_00000D_SCLK_CNTL, sclk_cntl);
 }
 
+static void r420_cp_errata_init(struct radeon_device *rdev)
+{
+        /* RV410 and R420 can lock up if CP DMA to host memory happens
+         * while the 2D engine is busy.
+         *
+         * The proper workaround is to queue a RESYNC at the beginning
+         * of the CP init, apparently.
+         */
+        radeon_scratch_get(rdev, &rdev->config.r300.resync_scratch);
+        radeon_ring_lock(rdev, 8);
+        radeon_ring_write(rdev, PACKET0(R300_CP_RESYNC_ADDR, 1));
+        radeon_ring_write(rdev, rdev->config.r300.resync_scratch);
+        radeon_ring_write(rdev, 0xDEADBEEF);
+        radeon_ring_unlock_commit(rdev);
+}
+
+static void r420_cp_errata_fini(struct radeon_device *rdev)
+{
+        /* Catch the RESYNC we dispatched all the way back,
+         * at the very beginning of the CP init.
+         */
+        radeon_ring_lock(rdev, 8);
+        radeon_ring_write(rdev, PACKET0(R300_RB3D_DSTCACHE_CTLSTAT, 0));
+        radeon_ring_write(rdev, R300_RB3D_DC_FINISH);
+        radeon_ring_unlock_commit(rdev);
+        radeon_scratch_free(rdev, rdev->config.r300.resync_scratch);
+}
+
 static int r420_startup(struct radeon_device *rdev)
 {
         int r;
@@ -196,6 +225,7 @@ static int r420_startup(struct radeon_device *rdev)
                 dev_err(rdev->dev, "failled initializing CP (%d).\n", r);
                 return r;
         }
+        r420_cp_errata_init(rdev);
         r = r100_wb_init(rdev);
         if (r) {
                 dev_err(rdev->dev, "failled initializing WB (%d).\n", r);
@@ -238,6 +268,7 @@ int r420_resume(struct radeon_device *rdev)
 
 int r420_suspend(struct radeon_device *rdev)
 {
+        r420_cp_errata_fini(rdev);
         r100_cp_disable(rdev);
         r100_wb_disable(rdev);
         r100_irq_disable(rdev);
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index a7e349dc4b97..cee8bdc6c9ff 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -674,6 +674,7 @@ struct r100_asic {
 struct r300_asic {
         const unsigned  *reg_safe_bm;
         unsigned        reg_safe_bm_size;
+        u32             resync_scratch;
 };
 
 struct r600_asic {