[Skiboot] [PATCH 2/2] npu2-hw-procedures.c: Correct phy lane mapping

[Alistair Popple]

Each nvlink device is associated with a particular group of OBUS lanes via
a lane mask which is read from HDAT via the device-tree. However Skiboot's
interpretation of lane mask was different to what is exported from the
HDAT.

Specifically the lane mask bits in the HDAT are encoded in IBM bit ordering
for a 24-bit wide value. So for example in normal bit ordering lane-0 is
represented by having lane-mask bit 23 set and lane-23 is represented by
lane-mask bit 0. This patch alters the Skiboot interpretation to match what
is passed from HDAT.

Signed-off-by: Alistair Popple <alistair at popple.id.au>
---
 hw/npu2-hw-procedures.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/npu2-hw-procedures.c b/hw/npu2-hw-procedures.c
index a43952d7..b21c399d 100644
--- a/hw/npu2-hw-procedures.c
+++ b/hw/npu2-hw-procedures.c
@@ -102,12 +102,12 @@ struct npu2_phy_reg NPU2_PHY_RX_CTL_DATASM_CLKDIST_PDWN = {0x2e0, 60, 1};
 #define NPU2_PHY_REG(scom_base, reg, lane)					\
 	SETFIELD(PPC_BITMASK(27, 31), ((reg)->offset << 42) | scom_base, lane)
 
-#define NPU2_MAX_PHY_LANES			24
+#define NPU2_MAX_PHY_LANE			23
 
 /* This is a bit of a gross hack but it does the job */
 #define FOR_EACH_LANE(ndev, lane) \
-	for (lane = 0; lane < NPU2_MAX_PHY_LANES; lane++)	\
-		if (!(ndev->lane_mask & (1 << lane)))		\
+	for (lane = 0; lane <= NPU2_MAX_PHY_LANE; lane++)	\
+		if (!(ndev->lane_mask & (1 << (NPU2_MAX_PHY_LANE - lane)))) \
 			continue;				\
 		else
 
-- 
2.11.0