[PATCH] drm/amdgpu: access ltr through pci cfg space

[Zhang, Hawking]

[AMD Official Use Only - AMD Internal Distribution Only]

Reviewed-by: Hawking Zhang <Hawking.Zhang at amd.com>

Regards,
Hawking
-----Original Message-----
From: Min, Frank <Frank.Min at amd.com>
Sent: Thursday, June 20, 2024 14:52
To: amd-gfx at lists.freedesktop.org
Cc: Deucher, Alexander <Alexander.Deucher at amd.com>; Zhang, Hawking <Hawking.Zhang at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>; Gao, Likun <Likun.Gao at amd.com>
Subject: [PATCH] drm/amdgpu: access ltr through pci cfg space

[AMD Official Use Only - AMD Internal Distribution Only]

From: Frank Min <Frank.Min at amd.com>

Access ltr through pci cfg space instead of mmio while programing aspm on gfx12

Signed-off-by: Frank Min <Frank.Min at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/nbif_v6_3_1.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/nbif_v6_3_1.c b/drivers/gpu/drm/amd/amdgpu/nbif_v6_3_1.c
index 5a20bb229788..39919e0892c1 100644
--- a/drivers/gpu/drm/amd/amdgpu/nbif_v6_3_1.c
+++ b/drivers/gpu/drm/amd/amdgpu/nbif_v6_3_1.c
@@ -345,6 +345,7 @@ static void nbif_v6_3_1_program_aspm(struct amdgpu_device *adev)  {  #ifdef CONFIG_PCIEASPM
        uint32_t def, data;
+       u16 devctl2, ltr;

        def = data = RREG32_SOC15(PCIE, 0, regPCIE_LC_CNTL);
        data &= ~PCIE_LC_CNTL__LC_L1_INACTIVITY_MASK;
@@ -374,12 +375,17 @@ static void nbif_v6_3_1_program_aspm(struct amdgpu_device *adev)
        if (def != data)
                WREG32_SOC15(NBIO, 0, regRCC_STRAP0_RCC_BIF_STRAP5, data);

-       def = data = RREG32_SOC15(NBIO, 0, regBIF_CFG_DEV0_EPF0_DEVICE_CNTL2);
-       data &= ~BIF_CFG_DEV0_EPF0_DEVICE_CNTL2__LTR_EN_MASK;
+       pcie_capability_read_word(adev->pdev, PCI_EXP_DEVCTL2, &devctl2);
+       data = def = devctl2;
+       data &= ~PCI_EXP_DEVCTL2_LTR_EN;
        if (def != data)
-               WREG32_SOC15(NBIO, 0, regBIF_CFG_DEV0_EPF0_DEVICE_CNTL2, data);
+               pcie_capability_set_word(adev->pdev, PCI_EXP_DEVCTL2, (u16)data);
+
+       ltr = pci_find_ext_capability(adev->pdev, PCI_EXT_CAP_ID_LTR);

-       WREG32_SOC15(NBIO, 0, regBIF_CFG_DEV0_EPF0_PCIE_LTR_CAP, 0x10011001);
+       if (ltr) {
+               pci_write_config_dword(adev->pdev, ltr + PCI_LTR_MAX_SNOOP_LAT, 0x10011001);
+       }

 #if 0
        /* regPSWUSP0_PCIE_LC_CNTL2 should be replace by PCIE_LC_CNTL2 or someone else ? */
--
2.34.1