drm/radeon/dpm: add a helper to encode pcie lane setting

convert from number of lanes to register setting.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/r600_dpm.c b/drivers/gpu/drm/radeon/r600_dpm.c
index 34ea5d6..89c46c5 100644 (file)
--- a/drivers/gpu/drm/radeon/r600_dpm.c
+++ b/drivers/gpu/drm/radeon/r600_dpm.c
@@ -1246,3 +1246,13 @@ u16 r600_get_pcie_lane_support(struct radeon_device *rdev,
                return 16;
        }
 }
+
+u8 r600_encode_pci_lane_width(u32 lanes)
+{
+       u8 encoded_lanes[] = { 0, 1, 2, 0, 3, 0, 0, 0, 4, 0, 0, 0, 5, 0, 0, 0, 6 };
+
+       if (lanes > 16)
+               return 0;
+
+       return encoded_lanes[lanes];
+}

diff --git a/drivers/gpu/drm/radeon/r600_dpm.h b/drivers/gpu/drm/radeon/r600_dpm.h
index 71d5d93..8dc1fbd 100644 (file)
--- a/drivers/gpu/drm/radeon/r600_dpm.h
+++ b/drivers/gpu/drm/radeon/r600_dpm.h
@@ -227,5 +227,6 @@ enum radeon_pcie_gen r600_get_pcie_gen_support(struct radeon_device *rdev,
 u16 r600_get_pcie_lane_support(struct radeon_device *rdev,
                               u16 asic_lanes,
                               u16 default_lanes);
+u8 r600_encode_pci_lane_width(u32 lanes);
 
 #endif