Re: [PATCH v6 3/4] venus: firmware: add no TZ boot and shutdown routine

[Vikash Garodia]

On 2018-08-27 08:36, Alexandre Courbot wrote:
> On Fri, Aug 24, 2018 at 9:26 PM Vikash Garodia 
> <vgarodia@xxxxxxxxxxxxxx> wrote:
> > Hi Alex,
> >
> > On 2018-08-24 13:09, Alexandre Courbot wrote:
> > > On Thu, Aug 23, 2018 at 11:29 PM Vikash Garodia
> > > <vgarodia@xxxxxxxxxxxxxx> wrote:
> >
> > [snip]
> >
> > >> +struct video_firmware {
> > >> +       struct device *dev;
> > >> +       struct iommu_domain *iommu_domain;
> > >> +};
> > >> +
> > >>  /**
> > >>   * struct venus_core - holds core parameters valid for all instances
> > >>   *
> > >> @@ -98,6 +103,7 @@ struct venus_caps {
> > >>   * @dev:               convenience struct device pointer
> > >>   * @dev_dec:   convenience struct device pointer for decoder device
> > >>   * @dev_enc:   convenience struct device pointer for encoder device
> > >> + * @fw:                a struct for venus firmware info
> > >>   * @no_tz:     a flag that suggests presence of trustzone
> > >>   * @lock:      a lock for this strucure
> > >>   * @instances: a list_head of all instances
> > >> @@ -130,6 +136,7 @@ struct venus_core {
> > >>         struct device *dev;
> > >>         struct device *dev_dec;
> > >>         struct device *dev_enc;
> > >> +       struct video_firmware fw;
> > >
> > > Since struct video_firmware is only used here I think you can declare
> > > it inline, i.e.
> > >
> > >     struct {
> > >         struct device *dev;
> > >         struct iommu_domain *iommu_domain;
> > >     } fw;
> > >
> > > This structure is actually a good candidate to hold the firmware
> > > memory area start address and size.
> >
> > I can make it inline.
> > Memory area and size are common parameters populated
> > locally while loading the firmware with or without tz. Firmware struct
> > has
> > info more specific to firmware device.
> >
> > [snip]
> >
> > >
> > >> +{
> > >> +       struct iommu_domain *iommu_dom;
> > >> +       struct device *dev;
> > >> +       int ret;
> > >> +
> > >> +       dev = core->fw.dev;
> > >> +       if (!dev)
> > >> +               return -EPROBE_DEFER;
> > >> +
> > >> +       iommu_dom = iommu_domain_alloc(&platform_bus_type);
> > >> +       if (!iommu_dom) {
> > >> +               dev_err(dev, "Failed to allocate iommu domain\n");
> > >> +               return -ENOMEM;
> > >> +       }
> > >> +
> > >> +       ret = iommu_attach_device(iommu_dom, dev);
> > >> +       if (ret) {
> > >> +               dev_err(dev, "could not attach device\n");
> > >> +               goto err_attach;
> > >> +       }
> > >
> > > I think like the above belongs more in venus_firmware_init()
> > > (introduced in patch 4/4) than here. There is no reason to
> > > detach/reattach the iommu if we stop the firmware.
> >
> > Consider the case when we want to reload the firmware during error
> > recovery.
> > Boot and shutdown will be needed in such case without the need to
> > populate
> > the firmware device again.
>
> Is there a need to reattach the iommu domain in case of an error?

re-attach is not needed. We can have alloc/attach in init and 
detach/free in deinit.
map/reset and unmap/reset can continue to remain in boot and shutdown 
calls. Let me
know if this is good, i can repatch the series.