Re: [PATCH 6/9] nvme-apple: Add initial Apple SoC NVMe driver

[Janne Grunau]

On 2022-04-02 15:34:55 +0200, Sven Peter wrote:
> 
> 
> On Tue, Mar 22, 2022, at 14:38, Arnd Bergmann wrote:
> > On Mon, Mar 21, 2022 at 5:50 PM Sven Peter <sven@xxxxxxxxxxxxx> wrote:
> >
> >> +static int apple_nvme_sart_dma_setup(void *cookie, struct apple_rtkit_shmem *bfr,
> >> +                                    dma_addr_t iova, size_t size)
> >> +{
> >> +       struct apple_nvme *anv = cookie;
> >> +       int ret;
> >> +
> >> +       if (iova)
> >> +               return -EINVAL;
> >> +
> >> +       bfr->buffer = dma_alloc_coherent(anv->dev, size, &iova, GFP_KERNEL);
> >> +       if (!bfr->buffer)
> >> +               return -ENOMEM;
> >
> > You pass 'iova' as an argument, but then replace it with the address
> > returned by dma_alloc_coherent(). Can you remove the function
> > argument?
> 
> Yup, will remove it.

You can remove it but we will have to add it back once we submit the dcp 
driver (display co-processor). dcp is initialized during boot and uses a 
single pre-allocated buffer which needs to be mapped instead of 
allocated. It seemed easier to make apple_rtkit_ops.shmem_setup() 
omnipotent than adding a different function pointer for this case.

Janne