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

[Frederic Barrat]

Le 24/01/2018 à 04:44, Alistair Popple a écrit :
> 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>
> ---

Thanks for the heads up!

Reviewed-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>

Andrew: please confirm you're seeing this. It obviously will have an 
impact when you merge it with your patchset (and I can see troubles 
ahead for our custom device tree on ZZ).

   Fred

>   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
>