[Skiboot] [PATCH 5/5] npu2-opencapi: Fix link state to report link down

[Andrew Donnellan]

On 12/04/18 22:45, Frederic Barrat wrote:
> From: Frederic Barrat <fbarrat at linux.vnet.ibm.com>
> 
> The PHB callback 'get_link_state' is always reporting the link width,
> irrespective of the link status and even when the link is down. It is
> causing too much work (and failures) when the PHB is probed during pci
> init.
> The fix is to look at the link status first and report the link as
> down when appropriate.
> 
> Signed-off-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>

Acked-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

> ---
>   hw/npu2-opencapi.c | 13 +++++++++++--
>   1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/npu2-opencapi.c b/hw/npu2-opencapi.c
> index 24adf5e1..a0fdf22b 100644
> --- a/hw/npu2-opencapi.c
> +++ b/hw/npu2-opencapi.c
> @@ -80,6 +80,7 @@
>   
>   #define OCAPI_LINK_TRAINING_RETRIES	5
>   #define OCAPI_LINK_TRAINING_TIMEOUT	3000 /* ms */
> +#define OCAPI_LINK_STATE_TRAINED        0x7
>   
>   enum npu2_link_training_state {
>   	NPU2_TRAIN_DEFAULT, /* fully train the link */
> @@ -1032,10 +1033,17 @@ static int64_t npu2_opencapi_get_link_state(struct pci_slot *slot, uint8_t *val)
>   {
>   	struct npu2_dev *dev = phb_to_npu2_dev_ocapi(slot->phb);
>   	uint64_t reg;
> -	int64_t link_width, rc = OPAL_SUCCESS;
> +	int64_t link_width, training_status, rc = OPAL_SUCCESS;
>   
>   	reg = get_odl_status(dev->npu->chip_id, dev->index);
>   	link_width = GETFIELD(OB_ODL_STATUS_TRAINED_MODE, reg);
> +	training_status = GETFIELD(OB_ODL_STATUS_TRAINING_STATE_MACHINE, reg);
> +
> +	if (training_status != OCAPI_LINK_STATE_TRAINED) {
> +		*val = OPAL_SHPC_LINK_DOWN;
> +		return OPAL_SUCCESS;
> +	}
> +
>   	switch (link_width) {
>   	case 0b0001:
>   		*val = OPAL_SHPC_LINK_UP_x4;
> @@ -1086,7 +1094,8 @@ static int64_t npu2_opencapi_poll_link(struct pci_slot *slot)
>   		/* fall-through */
>   	case OCAPI_SLOT_LINK_WAIT:
>   		reg = get_odl_status(chip_id, dev->index);
> -		if (GETFIELD(OB_ODL_STATUS_TRAINING_STATE_MACHINE, reg) == 0x7) {
> +		if (GETFIELD(OB_ODL_STATUS_TRAINING_STATE_MACHINE, reg) ==
> +			OCAPI_LINK_STATE_TRAINED) {
>   			OCAPIINF(dev, "link trained in %lld ms\n",
>   				OCAPI_LINK_TRAINING_TIMEOUT - slot->retries);
>   			pci_slot_set_state(slot, OCAPI_SLOT_LINK_TRAINED);
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited