RE: [PATCH] NTB: add support for hotplug feature

["Allen Hubbe" <Allen.Hubbe@dell.com>]

From: Shyam Sundar S K
> Hi Allen, Jon
> 
> Any feedback on the below changes ?
> 

Acked-by: Allen Hubbe <Allen.Hubbe@dell.com>

> Thanks,
> Shyam
> 
> On 11/18/2016 2:51 PM, Shyam Sundar S K wrote:
> > From: Xiangliang Yu <Xiangliang.Yu@amd.com>
> >
> > AMD NTB support hotplug under B2B mode. NTB will trigger link
> > up/down interrupt event when doing plug add/remove, this patch
> > implements the two interrupt event to support B2B hotplug function.
> >
> > Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
> > Signed-off-by: S-k, Shyam-sundar <Shyam-sundar.S-k@amd.com>
> > ---
> >  drivers/ntb/hw/amd/ntb_hw_amd.c | 9 ++++++++-
> >  drivers/ntb/hw/amd/ntb_hw_amd.h | 5 ++++-
> >  2 files changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/ntb/hw/amd/ntb_hw_amd.c b/drivers/ntb/hw/amd/ntb_hw_amd.c
> > index 9bbe3e0..2fc202c 100644
> > --- a/drivers/ntb/hw/amd/ntb_hw_amd.c
> > +++ b/drivers/ntb/hw/amd/ntb_hw_amd.c
> > @@ -194,6 +194,11 @@ static int amd_link_is_up(struct amd_ntb_dev *ndev)
> >  	if (!ndev->peer_sta)
> >  		return NTB_LNK_STA_ACTIVE(ndev->cntl_sta);
> >
> > +	if (ndev->peer_sta & AMD_LINK_UP_EVENT) {
> > +		ndev->peer_sta = 0;
> > +		return 1;
> > +	}
> > +
> >  	/* If peer_sta is reset or D0 event, the ISR has
> >  	 * started a timer to check link status of hardware.
> >  	 * So here just clear status bit. And if peer_sta is
> > @@ -202,7 +207,7 @@ static int amd_link_is_up(struct amd_ntb_dev *ndev)
> >  	 */
> >  	if (ndev->peer_sta & AMD_PEER_RESET_EVENT)
> >  		ndev->peer_sta &= ~AMD_PEER_RESET_EVENT;
> > -	else if (ndev->peer_sta & AMD_PEER_D0_EVENT)
> > +	else if (ndev->peer_sta & (AMD_PEER_D0_EVENT | AMD_LINK_DOWN_EVENT))
> >  		ndev->peer_sta = 0;
> >
> >  	return 0;
> > @@ -480,6 +485,8 @@ static void amd_handle_event(struct amd_ntb_dev *ndev, int vec)
> >  		break;
> >  	case AMD_PEER_D3_EVENT:
> >  	case AMD_PEER_PMETO_EVENT:
> > +	case AMD_LINK_UP_EVENT:
> > +	case AMD_LINK_DOWN_EVENT:
> >  		amd_ack_smu(ndev, status);
> >
> >  		/* link down */
> > diff --git a/drivers/ntb/hw/amd/ntb_hw_amd.h b/drivers/ntb/hw/amd/ntb_hw_amd.h
> > index 2eac3cd..13d73ed 100644
> > --- a/drivers/ntb/hw/amd/ntb_hw_amd.h
> > +++ b/drivers/ntb/hw/amd/ntb_hw_amd.h
> > @@ -148,9 +148,12 @@ enum {
> >  	AMD_PEER_D3_EVENT	= BIT(2),
> >  	AMD_PEER_PMETO_EVENT	= BIT(3),
> >  	AMD_PEER_D0_EVENT	= BIT(4),
> > +	AMD_LINK_UP_EVENT	= BIT(5),
> > +	AMD_LINK_DOWN_EVENT	= BIT(6),
> >  	AMD_EVENT_INTMASK	= (AMD_PEER_FLUSH_EVENT |
> >  				AMD_PEER_RESET_EVENT | AMD_PEER_D3_EVENT |
> > -				AMD_PEER_PMETO_EVENT | AMD_PEER_D0_EVENT),
> > +				AMD_PEER_PMETO_EVENT | AMD_PEER_D0_EVENT |
> > +				AMD_LINK_UP_EVENT | AMD_LINK_DOWN_EVENT),
> >
> >  	AMD_PMESTAT_OFFSET	= 0x480,
> >  	AMD_PMSGTRIG_OFFSET	= 0x490,
> >