[PATCH v3 03/10] drm/amdgpu: Use RMW accessors for changing LNKCTL2

Ilpo Järvinen
2023-09-29T11:58:26Z

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@wunner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@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 e63abdf52b6c..7bcd41996927 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 4b81f29e5fd5..8ea60fdd1b1d 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;
--
2.30.2