Re: [PATCH 3/7] accel/ivpu: Do not use SSID 1

[Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>]

On Wed, Mar 22, 2023 at 08:25:09AM -0600, Jeffrey Hugo wrote:
> On 3/22/2023 3:18 AM, Stanislaw Gruszka wrote:
> > The SSID=1 is used by the firmware as default value in
> > case SSID mapping is not initialized. This allows
> > detecting use of miss-configured memory contexts.
> > The future FW versions may not allow using SSID=1.
> > 
> > Co-developed-by: Andrzej Kacprowski <andrzej.kacprowski@linux.intel.com>
> > Signed-off-by: Andrzej Kacprowski <andrzej.kacprowski@linux.intel.com>
> > Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
> > ---
> >   drivers/accel/ivpu/ivpu_drv.c | 4 ++--
> >   drivers/accel/ivpu/ivpu_drv.h | 5 ++++-
> >   2 files changed, 6 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/accel/ivpu/ivpu_drv.c b/drivers/accel/ivpu/ivpu_drv.c
> > index d9e311b40348..70245cf84593 100644
> > --- a/drivers/accel/ivpu/ivpu_drv.c
> > +++ b/drivers/accel/ivpu/ivpu_drv.c
> > @@ -474,8 +474,8 @@ static int ivpu_dev_init(struct ivpu_device *vdev)
> >   	vdev->hw->ops = &ivpu_hw_mtl_ops;
> >   	vdev->platform = IVPU_PLATFORM_INVALID;
> > -	vdev->context_xa_limit.min = IVPU_GLOBAL_CONTEXT_MMU_SSID + 1;
> > -	vdev->context_xa_limit.max = IVPU_CONTEXT_LIMIT;
> > +	vdev->context_xa_limit.min = IVPU_USER_CONTEXT_MIN_SSID;
> > +	vdev->context_xa_limit.max = IVPU_USER_CONTEXT_MAX_SSID;
> >   	atomic64_set(&vdev->unique_id_counter, 0);
> >   	xa_init_flags(&vdev->context_xa, XA_FLAGS_ALLOC);
> >   	xa_init_flags(&vdev->submitted_jobs_xa, XA_FLAGS_ALLOC1);
> > diff --git a/drivers/accel/ivpu/ivpu_drv.h b/drivers/accel/ivpu/ivpu_drv.h
> > index 1b2aa05840ad..ef12a38e06e1 100644
> > --- a/drivers/accel/ivpu/ivpu_drv.h
> > +++ b/drivers/accel/ivpu/ivpu_drv.h
> > @@ -25,7 +25,10 @@
> >   #define PCI_DEVICE_ID_MTL   0x7d1d
> >   #define IVPU_GLOBAL_CONTEXT_MMU_SSID 0
> > -#define IVPU_CONTEXT_LIMIT	     64
> > +/* SSID 1 is used by the VPU to represent invalid context */
> > +#define IVPU_USER_CONTEXT_MIN_SSID   2
> > +#define IVPU_USER_CONTEXT_MAX_SSID   (IVPU_USER_CONTEXT_MIN_SSID + 63)
> 
> The old MAX was 64.  Now the MAX is 65.  I'm guessing the intent is to keep
> the number of valid SSIDs constant (63), but it is unclear if SSID 65 is
> valid for the FW.
> 
> Maybe the commit text could clarify this a bit?

Yes SSID=65 is valid, I'll update the changelog.

Regards
Stanislaw
>