Re: [PATCH v2] firmware: qcom: scm: Peripheral Authentication Service

[Bjorn Andersson <bjorn.andersson@sonymobile.com>]

On Wed 15 Jul 14:33 PDT 2015, Andy Gross wrote:

> On Wed, Jul 15, 2015 at 11:58:06AM -0700, Bjorn Andersson wrote:
> 
> <snip>
> 
> > +int __qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size)
> > +{
> > +	dma_addr_t mdata_phys;
> > +	void *mdata_buf;
> > +	__le32 scm_ret;
> > +	int ret;
> > +	struct pas_init_image_req {
> > +		__le32 proc;
> > +		__le32 image_addr;
> > +	} request;
> > +
> > +	/*
> > +	 * During the scm call memory protection will be enabled for the meta
> > +	 * data blob, so make sure it's physically contiguous, 4K aligned and
> > +	 * non-cachable to avoid XPU violations.
> > +	 */
> > +	mdata_buf = dma_alloc_coherent(NULL, size, &mdata_phys, GFP_KERNEL);
> 
> It'd be nice to send in the dev so we can attribute the allocation correctly.
> For 64 bit, we actually have to do this because NULL is not allowed right now.
> 

As per Stephen's answer I need to respin this anyways, but I think I
need to read up a little bit more on the implications of passing e.g.
the PIL dev* down here.

> > +	if (!mdata_buf) {
> > +		pr_err("Allocation of metadata buffer failed.\n");
> > +		return -ENOMEM;
> > +	}
> > +	memcpy(mdata_buf, metadata, size);
> > +
> > +	request.proc = cpu_to_le32(peripheral);
> > +	request.image_addr = cpu_to_le32(mdata_phys);
> > +
> > +	ret = qcom_scm_call(QCOM_SCM_SVC_PIL, QCOM_SCM_PAS_INIT_IMAGE_CMD,
> > +			    &request, sizeof(request),
> > +			    &scm_ret, sizeof(scm_ret));
> > +
> > +	dma_free_coherent(NULL, size, mdata_buf, mdata_phys);
> > +
> > +	return ret ? : le32_to_cpu(scm_ret);
> > +}
> > +
> 
> Otherwise, looks good.  Let me know if you plan to modify for the device above.
> If you want me to do it later, thats fine.  But it means API change.
> 

I'll respin this in a bit, need to read up a little bit more on the dma
allocation. But most likely I'll just move the allocation to the common
code, pass the physical address here and expect a dev* in the public
api.

Regards,
Bjorn