[PATCH 1/3] drm/radeon: Use RMW accessors for changing LNKCTL2

From: Ilpo Järvinen
Date: Thu Feb 15 2024 - 08:32:46 EST


Convert open coded RMW accesses for LNKCTL2 to use
pcie_capability_clear_and_set_word() which makes its easier to
understand what the code tries to do.

LNKCTL2 is not really owned by any driver because it is a collection of
control bits that PCI core might need to touch. RMW accessors already
have support for proper locking for a selected set of registers
(LNKCTL2 is not yet among them but likely will be in the future) to
avoid losing concurrent updates.

Suggested-by: Lukas Wunner <lukas@xxxxxxxxx>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/radeon/cik.c | 40 ++++++++++++++----------------------
drivers/gpu/drm/radeon/si.c | 40 ++++++++++++++----------------------
2 files changed, 30 insertions(+), 50 deletions(-)

diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index 10be30366c2b..b5e96a8fc2c1 100644
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -9592,28 +9592,18 @@ static void cik_pcie_gen3_enable(struct radeon_device *rdev)
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(rdev->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(rdev->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(rdev->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;
@@ -9627,15 +9617,15 @@ static void cik_pcie_gen3_enable(struct radeon_device *rdev)
speed_cntl &= ~LC_FORCE_DIS_SW_SPEED_CHANGE;
WREG32_PCIE_PORT(PCIE_LC_SPEED_CNTL, speed_cntl);

- pcie_capability_read_word(rdev->pdev, PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~PCI_EXP_LNKCTL2_TLS;
+ tmp16 = 0;
if (speed_cap == PCIE_SPEED_8_0GT)
tmp16 |= PCI_EXP_LNKCTL2_TLS_8_0GT; /* gen3 */
else if (speed_cap == PCIE_SPEED_5_0GT)
tmp16 |= PCI_EXP_LNKCTL2_TLS_5_0GT; /* gen2 */
else
tmp16 |= PCI_EXP_LNKCTL2_TLS_2_5GT; /* gen1 */
- pcie_capability_write_word(rdev->pdev, PCI_EXP_LNKCTL2, tmp16);
+ pcie_capability_clear_and_set_word(rdev->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;
diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index 85e9cba49cec..8eeaea64c75d 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -7193,28 +7193,18 @@ static void si_pcie_gen3_enable(struct radeon_device *rdev)
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(rdev->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(rdev->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(rdev->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;
@@ -7228,15 +7218,15 @@ static void si_pcie_gen3_enable(struct radeon_device *rdev)
speed_cntl &= ~LC_FORCE_DIS_SW_SPEED_CHANGE;
WREG32_PCIE_PORT(PCIE_LC_SPEED_CNTL, speed_cntl);

- pcie_capability_read_word(rdev->pdev, PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~PCI_EXP_LNKCTL2_TLS;
+ tmp16 = 0;
if (speed_cap == PCIE_SPEED_8_0GT)
tmp16 |= PCI_EXP_LNKCTL2_TLS_8_0GT; /* gen3 */
else if (speed_cap == PCIE_SPEED_5_0GT)
tmp16 |= PCI_EXP_LNKCTL2_TLS_5_0GT; /* gen2 */
else
tmp16 |= PCI_EXP_LNKCTL2_TLS_2_5GT; /* gen1 */
- pcie_capability_write_word(rdev->pdev, PCI_EXP_LNKCTL2, tmp16);
+ pcie_capability_clear_and_set_word(rdev->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