drm/radeon: implement pci config reset for r6xx/7xx (v3)

pci config reset is a low level reset that resets
the entire chip from the bus interface.  It can
be more reliable if soft reset fails.

There's not much information still available on
r6xx, so r6xx is based on guess-work.

v2: put behind module parameter
v3: add IGP check

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index bf0792cf0729..ad99bae2e85c 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -105,6 +105,7 @@ void r600_fini(struct radeon_device *rdev);
 void r600_irq_disable(struct radeon_device *rdev);
 static void r600_pcie_gen2_enable(struct radeon_device *rdev);
 extern int evergreen_rlc_resume(struct radeon_device *rdev);
+extern void rv770_set_clk_bypass_mode(struct radeon_device *rdev);
 
 /**
  * r600_get_xclk - get the xclk
@@ -1644,6 +1645,67 @@ static void r600_gpu_soft_reset(struct radeon_device *rdev, u32 reset_mask)
 	r600_print_gpu_status_regs(rdev);
 }
 
+static void r600_gpu_pci_config_reset(struct radeon_device *rdev)
+{
+	struct rv515_mc_save save;
+	u32 tmp, i;
+
+	dev_info(rdev->dev, "GPU pci config reset\n");
+
+	/* disable dpm? */
+
+	/* Disable CP parsing/prefetching */
+	if (rdev->family >= CHIP_RV770)
+		WREG32(R_0086D8_CP_ME_CNTL, S_0086D8_CP_ME_HALT(1) | S_0086D8_CP_PFP_HALT(1));
+	else
+		WREG32(R_0086D8_CP_ME_CNTL, S_0086D8_CP_ME_HALT(1));
+
+	/* disable the RLC */
+	WREG32(RLC_CNTL, 0);
+
+	/* Disable DMA */
+	tmp = RREG32(DMA_RB_CNTL);
+	tmp &= ~DMA_RB_ENABLE;
+	WREG32(DMA_RB_CNTL, tmp);
+
+	mdelay(50);
+
+	/* set mclk/sclk to bypass */
+	if (rdev->family >= CHIP_RV770)
+		rv770_set_clk_bypass_mode(rdev);
+	/* disable BM */
+	pci_clear_master(rdev->pdev);
+	/* disable mem access */
+	rv515_mc_stop(rdev, &save);
+	if (r600_mc_wait_for_idle(rdev)) {
+		dev_warn(rdev->dev, "Wait for MC idle timedout !\n");
+	}
+
+	/* BIF reset workaround.  Not sure if this is needed on 6xx */
+	tmp = RREG32(BUS_CNTL);
+	tmp |= VGA_COHE_SPEC_TIMER_DIS;
+	WREG32(BUS_CNTL, tmp);
+
+	tmp = RREG32(BIF_SCRATCH0);
+
+	/* reset */
+	radeon_pci_config_reset(rdev);
+	mdelay(1);
+
+	/* BIF reset workaround.  Not sure if this is needed on 6xx */
+	tmp = SOFT_RESET_BIF;
+	WREG32(SRBM_SOFT_RESET, tmp);
+	mdelay(1);
+	WREG32(SRBM_SOFT_RESET, 0);
+
+	/* wait for asic to come out of reset */
+	for (i = 0; i < rdev->usec_timeout; i++) {
+		if (RREG32(CONFIG_MEMSIZE) != 0xffffffff)
+			break;
+		udelay(1);
+	}
+}
+
 int r600_asic_reset(struct radeon_device *rdev)
 {
 	u32 reset_mask;
@@ -1653,10 +1715,17 @@ int r600_asic_reset(struct radeon_device *rdev)
 	if (reset_mask)
 		r600_set_bios_scratch_engine_hung(rdev, true);
 
+	/* try soft reset */
 	r600_gpu_soft_reset(rdev, reset_mask);
 
 	reset_mask = r600_gpu_check_soft_reset(rdev);
 
+	/* try pci config reset */
+	if (reset_mask && radeon_hard_reset)
+		r600_gpu_pci_config_reset(rdev);
+
+	reset_mask = r600_gpu_check_soft_reset(rdev);
+
 	if (!reset_mask)
 		r600_set_bios_scratch_engine_hung(rdev, false);