[PATCH v4 3/8] drm/amdgpu: Use RMW accessors for changing LNKCTL2

[Ilpo Järvinen]

Don't assume that only the driver would be accessing LNKCTL2. In the
case of upstream (parent), the driver does not even own the device it's
changing the registers for.

Use RMW capability accessors which do proper locking to avoid losing
concurrent updates to the register value. This change is also useful as
a cleanup.

Suggested-by: Lukas Wunner <lukas at wunner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen at linux.intel.com>
---
 drivers/gpu/drm/amd/amdgpu/cik.c | 41 ++++++++++++--------------------
 drivers/gpu/drm/amd/amdgpu/si.c  | 41 ++++++++++++--------------------
 2 files changed, 30 insertions(+), 52 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/cik.c b/drivers/gpu/drm/amd/amdgpu/cik.c
index 4dfaa017cf7f..a3a643254d7a 100644
--- a/drivers/gpu/drm/amd/amdgpu/cik.c
+++ b/drivers/gpu/drm/amd/amdgpu/cik.c
@@ -1638,28 +1638,18 @@ static void cik_pcie_gen3_enable(struct amdgpu_device *adev)
 								   PCI_EXP_LNKCTL_HAWD);
 
 				/* linkctl2 */
-				pcie_capability_read_word(root, PCI_EXP_LNKCTL2,
-							  &tmp16);
-				tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
-					   PCI_EXP_LNKCTL2_TX_MARGIN);
-				tmp16 |= (bridge_cfg2 &
-					  (PCI_EXP_LNKCTL2_ENTER_COMP |
-					   PCI_EXP_LNKCTL2_TX_MARGIN));
-				pcie_capability_write_word(root,
-							   PCI_EXP_LNKCTL2,
-							   tmp16);
-
-				pcie_capability_read_word(adev->pdev,
-							  PCI_EXP_LNKCTL2,
-							  &tmp16);
-				tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
-					   PCI_EXP_LNKCTL2_TX_MARGIN);
-				tmp16 |= (gpu_cfg2 &
-					  (PCI_EXP_LNKCTL2_ENTER_COMP |
-					   PCI_EXP_LNKCTL2_TX_MARGIN));
-				pcie_capability_write_word(adev->pdev,
-							   PCI_EXP_LNKCTL2,
-							   tmp16);
+				pcie_capability_clear_and_set_word(root, PCI_EXP_LNKCTL2,
+								   PCI_EXP_LNKCTL2_ENTER_COMP |
+								   PCI_EXP_LNKCTL2_TX_MARGIN,
+								   bridge_cfg2 &
+								   (PCI_EXP_LNKCTL2_ENTER_COMP |
+								    PCI_EXP_LNKCTL2_TX_MARGIN));
+				pcie_capability_clear_and_set_word(adev->pdev, PCI_EXP_LNKCTL2,
+								   PCI_EXP_LNKCTL2_ENTER_COMP |
+								   PCI_EXP_LNKCTL2_TX_MARGIN,
+								   gpu_cfg2 &
+								   (PCI_EXP_LNKCTL2_ENTER_COMP |
+								    PCI_EXP_LNKCTL2_TX_MARGIN));
 
 				tmp = RREG32_PCIE(ixPCIE_LC_CNTL4);
 				tmp &= ~PCIE_LC_CNTL4__LC_SET_QUIESCE_MASK;
@@ -1674,16 +1664,15 @@ static void cik_pcie_gen3_enable(struct amdgpu_device *adev)
 	speed_cntl &= ~PCIE_LC_SPEED_CNTL__LC_FORCE_DIS_SW_SPEED_CHANGE_MASK;
 	WREG32_PCIE(ixPCIE_LC_SPEED_CNTL, speed_cntl);
 
-	pcie_capability_read_word(adev->pdev, PCI_EXP_LNKCTL2, &tmp16);
-	tmp16 &= ~PCI_EXP_LNKCTL2_TLS;
-
+	tmp16 = 0;
 	if (adev->pm.pcie_gen_mask & CAIL_PCIE_LINK_SPEED_SUPPORT_GEN3)
 		tmp16 |= PCI_EXP_LNKCTL2_TLS_8_0GT; /* gen3 */
 	else if (adev->pm.pcie_gen_mask & CAIL_PCIE_LINK_SPEED_SUPPORT_GEN2)
 		tmp16 |= PCI_EXP_LNKCTL2_TLS_5_0GT; /* gen2 */
 	else
 		tmp16 |= PCI_EXP_LNKCTL2_TLS_2_5GT; /* gen1 */
-	pcie_capability_write_word(adev->pdev, PCI_EXP_LNKCTL2, tmp16);
+	pcie_capability_clear_and_set_word(adev->pdev, PCI_EXP_LNKCTL2,
+					   PCI_EXP_LNKCTL2_TLS, tmp16);
 
 	speed_cntl = RREG32_PCIE(ixPCIE_LC_SPEED_CNTL);
 	speed_cntl |= PCIE_LC_SPEED_CNTL__LC_INITIATE_LINK_SPEED_CHANGE_MASK;
diff --git a/drivers/gpu/drm/amd/amdgpu/si.c b/drivers/gpu/drm/amd/amdgpu/si.c
index a757526153e5..23e4ef4fff7c 100644
--- a/drivers/gpu/drm/amd/amdgpu/si.c
+++ b/drivers/gpu/drm/amd/amdgpu/si.c
@@ -2331,28 +2331,18 @@ static void si_pcie_gen3_enable(struct amdgpu_device *adev)
 								   gpu_cfg &
 								   PCI_EXP_LNKCTL_HAWD);
 
-				pcie_capability_read_word(root, PCI_EXP_LNKCTL2,
-							  &tmp16);
-				tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
-					   PCI_EXP_LNKCTL2_TX_MARGIN);
-				tmp16 |= (bridge_cfg2 &
-					  (PCI_EXP_LNKCTL2_ENTER_COMP |
-					   PCI_EXP_LNKCTL2_TX_MARGIN));
-				pcie_capability_write_word(root,
-							   PCI_EXP_LNKCTL2,
-							   tmp16);
-
-				pcie_capability_read_word(adev->pdev,
-							  PCI_EXP_LNKCTL2,
-							  &tmp16);
-				tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
-					   PCI_EXP_LNKCTL2_TX_MARGIN);
-				tmp16 |= (gpu_cfg2 &
-					  (PCI_EXP_LNKCTL2_ENTER_COMP |
-					   PCI_EXP_LNKCTL2_TX_MARGIN));
-				pcie_capability_write_word(adev->pdev,
-							   PCI_EXP_LNKCTL2,
-							   tmp16);
+				pcie_capability_clear_and_set_word(root, PCI_EXP_LNKCTL2,
+								   PCI_EXP_LNKCTL2_ENTER_COMP |
+								   PCI_EXP_LNKCTL2_TX_MARGIN,
+								   bridge_cfg2 &
+								   (PCI_EXP_LNKCTL2_ENTER_COMP |
+								    PCI_EXP_LNKCTL2_TX_MARGIN));
+				pcie_capability_clear_and_set_word(adev->pdev, PCI_EXP_LNKCTL2,
+								   PCI_EXP_LNKCTL2_ENTER_COMP |
+								   PCI_EXP_LNKCTL2_TX_MARGIN,
+								   gpu_cfg2 &
+								   (PCI_EXP_LNKCTL2_ENTER_COMP |
+								    PCI_EXP_LNKCTL2_TX_MARGIN));
 
 				tmp = RREG32_PCIE_PORT(PCIE_LC_CNTL4);
 				tmp &= ~LC_SET_QUIESCE;
@@ -2365,16 +2355,15 @@ static void si_pcie_gen3_enable(struct amdgpu_device *adev)
 	speed_cntl &= ~LC_FORCE_DIS_SW_SPEED_CHANGE;
 	WREG32_PCIE_PORT(PCIE_LC_SPEED_CNTL, speed_cntl);
 
-	pcie_capability_read_word(adev->pdev, PCI_EXP_LNKCTL2, &tmp16);
-	tmp16 &= ~PCI_EXP_LNKCTL2_TLS;
-
+	tmp16 = 0;
 	if (adev->pm.pcie_gen_mask & CAIL_PCIE_LINK_SPEED_SUPPORT_GEN3)
 		tmp16 |= PCI_EXP_LNKCTL2_TLS_8_0GT; /* gen3 */
 	else if (adev->pm.pcie_gen_mask & CAIL_PCIE_LINK_SPEED_SUPPORT_GEN2)
 		tmp16 |= PCI_EXP_LNKCTL2_TLS_5_0GT; /* gen2 */
 	else
 		tmp16 |= PCI_EXP_LNKCTL2_TLS_2_5GT; /* gen1 */
-	pcie_capability_write_word(adev->pdev, PCI_EXP_LNKCTL2, tmp16);
+	pcie_capability_clear_and_set_word(adev->pdev, PCI_EXP_LNKCTL2,
+					   PCI_EXP_LNKCTL2_TLS, tmp16);
 
 	speed_cntl = RREG32_PCIE_PORT(PCIE_LC_SPEED_CNTL);
 	speed_cntl |= LC_INITIATE_LINK_SPEED_CHANGE;
-- 
2.39.2