2019-11-11 19:33:14

by Bjorn Helgaas

[permalink] [raw]
Subject: [PATCH v2 0/2] drm: replace magic numbers

From: Bjorn Helgaas <[email protected]>

amdgpu and radeon do a bit of mucking with the PCIe Link Control 2
register, some of it using hard-coded magic numbers. The idea here is to
replace those with #defines.

I don't intend the Target Link Speed patch to change anything, so it should
be straightforward to review.

Since v1:
- Add my signed-off-by and Alex's reviewed-by.

Bjorn Helgaas (2):
drm: replace incorrect Compliance/Margin magic numbers with
PCI_EXP_LNKCTL2 definitions
drm: replace Target Link Speed magic numbers with PCI_EXP_LNKCTL2
definitions

drivers/gpu/drm/amd/amdgpu/cik.c | 22 ++++++++++++++--------
drivers/gpu/drm/amd/amdgpu/si.c | 18 +++++++++++-------
drivers/gpu/drm/radeon/cik.c | 22 ++++++++++++++--------
drivers/gpu/drm/radeon/si.c | 22 ++++++++++++++--------
include/uapi/linux/pci_regs.h | 2 ++
5 files changed, 55 insertions(+), 31 deletions(-)

--
2.24.0.rc1.363.gb1bccd3e3d-goog


2019-11-11 19:33:16

by Bjorn Helgaas

[permalink] [raw]
Subject: [PATCH 1/2] drm: replace incorrect Compliance/Margin magic numbers with PCI_EXP_LNKCTL2 definitions

From: Bjorn Helgaas <[email protected]>

Add definitions for these PCIe Link Control 2 register fields:

Enter Compliance
Transmit Margin

and use them in amdgpu and radeon.

NOTE: This is a functional change because "7 << 9" was apparently a typo.
That mask included the high order bit of Transmit Margin, the Enter
Modified Compliance bit, and the Compliance SOS bit, but I think what
was intended was the 3-bit Transmit Margin field at bits 9:7.

Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Alex Deucher <[email protected]>
---
drivers/gpu/drm/amd/amdgpu/cik.c | 14 ++++++++++----
drivers/gpu/drm/amd/amdgpu/si.c | 10 +++++++---
drivers/gpu/drm/radeon/cik.c | 14 ++++++++++----
drivers/gpu/drm/radeon/si.c | 14 ++++++++++----
include/uapi/linux/pci_regs.h | 2 ++
5 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/cik.c b/drivers/gpu/drm/amd/amdgpu/cik.c
index b81bb414fcb3..e4a595cdd4c1 100644
--- a/drivers/gpu/drm/amd/amdgpu/cik.c
+++ b/drivers/gpu/drm/amd/amdgpu/cik.c
@@ -1498,13 +1498,19 @@ static void cik_pcie_gen3_enable(struct amdgpu_device *adev)

/* linkctl2 */
pci_read_config_word(root, bridge_pos + PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~((1 << 4) | (7 << 9));
- tmp16 |= (bridge_cfg2 & ((1 << 4) | (7 << 9)));
+ tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN);
+ tmp16 |= (bridge_cfg2 &
+ (PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN));
pci_write_config_word(root, bridge_pos + PCI_EXP_LNKCTL2, tmp16);

pci_read_config_word(adev->pdev, gpu_pos + PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~((1 << 4) | (7 << 9));
- tmp16 |= (gpu_cfg2 & ((1 << 4) | (7 << 9)));
+ tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN);
+ tmp16 |= (gpu_cfg2 &
+ (PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN));
pci_write_config_word(adev->pdev, gpu_pos + PCI_EXP_LNKCTL2, tmp16);

tmp = RREG32_PCIE(ixPCIE_LC_CNTL4);
diff --git a/drivers/gpu/drm/amd/amdgpu/si.c b/drivers/gpu/drm/amd/amdgpu/si.c
index 493af42152f2..cf543410a424 100644
--- a/drivers/gpu/drm/amd/amdgpu/si.c
+++ b/drivers/gpu/drm/amd/amdgpu/si.c
@@ -1737,12 +1737,16 @@ static void si_pcie_gen3_enable(struct amdgpu_device *adev)
pci_write_config_word(adev->pdev, gpu_pos + PCI_EXP_LNKCTL, tmp16);

pci_read_config_word(root, bridge_pos + PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~((1 << 4) | (7 << 9));
- tmp16 |= (bridge_cfg2 & ((1 << 4) | (7 << 9)));
+ tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN);
+ tmp16 |= (bridge_cfg2 &
+ (PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN));
pci_write_config_word(root, bridge_pos + PCI_EXP_LNKCTL2, tmp16);

pci_read_config_word(adev->pdev, gpu_pos + PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~((1 << 4) | (7 << 9));
+ tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN);
tmp16 |= (gpu_cfg2 & ((1 << 4) | (7 << 9)));
pci_write_config_word(adev->pdev, gpu_pos + PCI_EXP_LNKCTL2, tmp16);

diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index 62eab82a64f9..95ffa0bff2d8 100644
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -9619,13 +9619,19 @@ static void cik_pcie_gen3_enable(struct radeon_device *rdev)

/* linkctl2 */
pci_read_config_word(root, bridge_pos + PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~((1 << 4) | (7 << 9));
- tmp16 |= (bridge_cfg2 & ((1 << 4) | (7 << 9)));
+ tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN);
+ tmp16 |= (bridge_cfg2 &
+ (PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN));
pci_write_config_word(root, bridge_pos + PCI_EXP_LNKCTL2, tmp16);

pci_read_config_word(rdev->pdev, gpu_pos + PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~((1 << 4) | (7 << 9));
- tmp16 |= (gpu_cfg2 & ((1 << 4) | (7 << 9)));
+ tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN);
+ tmp16 |= (gpu_cfg2 &
+ (PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN));
pci_write_config_word(rdev->pdev, gpu_pos + PCI_EXP_LNKCTL2, tmp16);

tmp = RREG32_PCIE_PORT(PCIE_LC_CNTL4);
diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index 05894d198a79..69993d34d1e9 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -7202,13 +7202,19 @@ static void si_pcie_gen3_enable(struct radeon_device *rdev)

/* linkctl2 */
pci_read_config_word(root, bridge_pos + PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~((1 << 4) | (7 << 9));
- tmp16 |= (bridge_cfg2 & ((1 << 4) | (7 << 9)));
+ tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN);
+ tmp16 |= (bridge_cfg2 &
+ (PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN));
pci_write_config_word(root, bridge_pos + PCI_EXP_LNKCTL2, tmp16);

pci_read_config_word(rdev->pdev, gpu_pos + PCI_EXP_LNKCTL2, &tmp16);
- tmp16 &= ~((1 << 4) | (7 << 9));
- tmp16 |= (gpu_cfg2 & ((1 << 4) | (7 << 9)));
+ tmp16 &= ~(PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN);
+ tmp16 |= (gpu_cfg2 &
+ (PCI_EXP_LNKCTL2_ENTER_COMP |
+ PCI_EXP_LNKCTL2_TX_MARGIN));
pci_write_config_word(rdev->pdev, gpu_pos + PCI_EXP_LNKCTL2, tmp16);

tmp = RREG32_PCIE_PORT(PCIE_LC_CNTL4);
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 29d6e93fd15e..5869e5778a05 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -673,6 +673,8 @@
#define PCI_EXP_LNKCTL2_TLS_8_0GT 0x0003 /* Supported Speed 8GT/s */
#define PCI_EXP_LNKCTL2_TLS_16_0GT 0x0004 /* Supported Speed 16GT/s */
#define PCI_EXP_LNKCTL2_TLS_32_0GT 0x0005 /* Supported Speed 32GT/s */
+#define PCI_EXP_LNKCTL2_ENTER_COMP 0x0010 /* Enter Compliance */
+#define PCI_EXP_LNKCTL2_TX_MARGIN 0x0380 /* Transmit Margin */
#define PCI_EXP_LNKSTA2 50 /* Link Status 2 */
#define PCI_CAP_EXP_ENDPOINT_SIZEOF_V2 52 /* v2 endpoints with link end here */
#define PCI_EXP_SLTCAP2 52 /* Slot Capabilities 2 */
--
2.24.0.rc1.363.gb1bccd3e3d-goog

2019-11-12 16:49:49

by Michel Dänzer

[permalink] [raw]
Subject: Re: [PATCH 1/2] drm: replace incorrect Compliance/Margin magic numbers with PCI_EXP_LNKCTL2 definitions

On 2019-11-11 8:29 p.m., Bjorn Helgaas wrote:
> From: Bjorn Helgaas <[email protected]>
>
> Add definitions for these PCIe Link Control 2 register fields:
>
> Enter Compliance
> Transmit Margin
>
> and use them in amdgpu and radeon.
>
> NOTE: This is a functional change because "7 << 9" was apparently a typo.
> That mask included the high order bit of Transmit Margin, the Enter
> Modified Compliance bit, and the Compliance SOS bit, but I think what
> was intended was the 3-bit Transmit Margin field at bits 9:7.

Can you split out the functional change into a separate patch 1? That
could make things easier for anyone who bisects the functional change
for whatever reason.


--
Earthling Michel Dänzer | https://redhat.com
Libre software enthusiast | Mesa and X developer

2019-11-12 17:20:38

by Bjorn Helgaas

[permalink] [raw]
Subject: Re: [PATCH 1/2] drm: replace incorrect Compliance/Margin magic numbers with PCI_EXP_LNKCTL2 definitions

On Tue, Nov 12, 2019 at 05:45:15PM +0100, Michel D?nzer wrote:
> On 2019-11-11 8:29 p.m., Bjorn Helgaas wrote:
> > From: Bjorn Helgaas <[email protected]>
> >
> > Add definitions for these PCIe Link Control 2 register fields:
> >
> > Enter Compliance
> > Transmit Margin
> >
> > and use them in amdgpu and radeon.
> >
> > NOTE: This is a functional change because "7 << 9" was apparently a typo.
> > That mask included the high order bit of Transmit Margin, the Enter
> > Modified Compliance bit, and the Compliance SOS bit, but I think what
> > was intended was the 3-bit Transmit Margin field at bits 9:7.
>
> Can you split out the functional change into a separate patch 1? That
> could make things easier for anyone who bisects the functional change
> for whatever reason.

Great idea, thanks! Wish I'd thought of that.

While fixing that, I also noticed I missed one case in
amdgpu/si.c. I'll post a v3.