From: Evan Quan evan.quan@amd.com
commit 5a5da8ae9546031e43efd4fa5aa8baa481e83dfb upstream.
A lot of NAK-G being generated when link widht switching is happening. WA for this issue is to program the SPC to 4 symbols per clock during bootup when the native PCIE width is x4.
Signed-off-by: Evan Quan evan.quan@amd.com Reviewed-by: Lijo Lazar lijo.lazar@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/amd/amdgpu/amdgpu_nbio.h | 1 + drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c | 28 ++++++++++++++++++++++++++++ drivers/gpu/drm/amd/amdgpu/nv.c | 3 +++ 3 files changed, 32 insertions(+)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_nbio.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_nbio.h @@ -93,6 +93,7 @@ struct amdgpu_nbio_funcs { void (*enable_aspm)(struct amdgpu_device *adev, bool enable); void (*program_aspm)(struct amdgpu_device *adev); + void (*apply_lc_spc_mode_wa)(struct amdgpu_device *adev); };
struct amdgpu_nbio { --- a/drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c +++ b/drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c @@ -51,6 +51,8 @@ #define mmBIF_MMSCH1_DOORBELL_RANGE 0x01d8 #define mmBIF_MMSCH1_DOORBELL_RANGE_BASE_IDX 2
+#define smnPCIE_LC_LINK_WIDTH_CNTL 0x11140288 + static void nbio_v2_3_remap_hdp_registers(struct amdgpu_device *adev) { WREG32_SOC15(NBIO, 0, mmREMAP_HDP_MEM_FLUSH_CNTL, @@ -463,6 +465,31 @@ static void nbio_v2_3_program_aspm(struc WREG32_PCIE(smnPCIE_LC_CNTL3, data); }
+static void nbio_v2_3_apply_lc_spc_mode_wa(struct amdgpu_device *adev) +{ + uint32_t reg_data = 0; + uint32_t link_width = 0; + + if (!((adev->asic_type >= CHIP_NAVI10) && + (adev->asic_type <= CHIP_NAVI12))) + return; + + reg_data = RREG32_PCIE(smnPCIE_LC_LINK_WIDTH_CNTL); + link_width = (reg_data & PCIE_LC_LINK_WIDTH_CNTL__LC_LINK_WIDTH_RD_MASK) + >> PCIE_LC_LINK_WIDTH_CNTL__LC_LINK_WIDTH_RD__SHIFT; + + /* + * Program PCIE_LC_CNTL6.LC_SPC_MODE_8GT to 0x2 (4 symbols per clock data) + * if link_width is 0x3 (x4) + */ + if (0x3 == link_width) { + reg_data = RREG32_PCIE(smnPCIE_LC_CNTL6); + reg_data &= ~PCIE_LC_CNTL6__LC_SPC_MODE_8GT_MASK; + reg_data |= (0x2 << PCIE_LC_CNTL6__LC_SPC_MODE_8GT__SHIFT); + WREG32_PCIE(smnPCIE_LC_CNTL6, reg_data); + } +} + const struct amdgpu_nbio_funcs nbio_v2_3_funcs = { .get_hdp_flush_req_offset = nbio_v2_3_get_hdp_flush_req_offset, .get_hdp_flush_done_offset = nbio_v2_3_get_hdp_flush_done_offset, @@ -484,4 +511,5 @@ const struct amdgpu_nbio_funcs nbio_v2_3 .remap_hdp_registers = nbio_v2_3_remap_hdp_registers, .enable_aspm = nbio_v2_3_enable_aspm, .program_aspm = nbio_v2_3_program_aspm, + .apply_lc_spc_mode_wa = nbio_v2_3_apply_lc_spc_mode_wa, }; --- a/drivers/gpu/drm/amd/amdgpu/nv.c +++ b/drivers/gpu/drm/amd/amdgpu/nv.c @@ -1194,6 +1194,9 @@ static int nv_common_hw_init(void *handl { struct amdgpu_device *adev = (struct amdgpu_device *)handle;
+ if (adev->nbio.funcs->apply_lc_spc_mode_wa) + adev->nbio.funcs->apply_lc_spc_mode_wa(adev); + /* enable pcie gen2/3 link */ nv_pcie_gen3_enable(adev); /* enable aspm */