Re: [PATCH 1/2] remoteproc: imx_dsp_rproc: add mandatory find_loaded_rsc_table op

Mathieu Poirier
2023-07-18T15:23:30Z

On Tue, Jul 18, 2023 at 11:25:03AM +0300, Iuliana Prodan wrote:
> On 7/17/2023 8:42 PM, Mathieu Poirier wrote:
> > On Thu, Jul 13, 2023 at 01:42:20AM +0300, Iuliana Prodan (OSS) wrote:
> > > From: Iuliana Prodan <iuliana.prodan@nxp.com>
> > >
> > > Add the .find_loaded_rsc_table operation for i.MX DSP.
> > > We need it for inter-process communication between DSP
> > > and main core.
> > >
> > > This callback is used to find the resource table (defined
> > > in remote processor linker script) where the address of the
> > > vrings along with the other allocated resources (carveouts etc)
> > > are stored.
> > > If this is not found, the vrings are not allocated and
> > > the IPC between cores will not work.
> > Is there a constraint on the system memory the M4 can address? If so there
> > will be a need to declare address ranges for vrings and buffers in reserved
> > memory in the DT.
> >
> > Thanks,
> > Mathieu
>
> Hi Mathieu,
>
> No, there is no constraint on memory.
>
> We want the Cortex A core to communicate with the HiFi4 DSP.
> The Cortex A is in charge of starting the DSP and loading the firmware in
> HiFi4's memory.
> When using rpmsg for IPC, the Cortex A needs to find the resource table
> (defined in the DSP linker script) and this is done using
> .find_loaded_rsc_table callback.
>
> For the DT, we are using a (not upstream) device tree where we have the
> reserved-memory for dsp_vdev0vring0, dsp_vdev0vring1 and dsp_vdev0buffer.

That is the part I'm interested in. Don't we need the reserved-memory entries?
Otherwise the M4 may not be able to access the memory chosen by the application
processor, most likely leading to a crash.

>
> Iulia
>
>
> > > Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
> > > ---
> > > drivers/remoteproc/imx_dsp_rproc.c | 1 +
> > > 1 file changed, 1 insertion(+)
> > >
> > > diff --git a/drivers/remoteproc/imx_dsp_rproc.c b/drivers/remoteproc/imx_dsp_rproc.c
> > > index d95fa5586189..b5634507d953 100644
> > > --- a/drivers/remoteproc/imx_dsp_rproc.c
> > > +++ b/drivers/remoteproc/imx_dsp_rproc.c
> > > @@ -941,6 +941,7 @@ static const struct rproc_ops imx_dsp_rproc_ops = {
> > > .kick = imx_dsp_rproc_kick,
> > > .load = imx_dsp_rproc_elf_load_segments,
> > > .parse_fw = imx_dsp_rproc_parse_fw,
> > > + .find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
> > > .sanity_check = rproc_elf_sanity_check,
> > > .get_boot_addr = rproc_elf_get_boot_addr,
> > > };
> > > --
> > > 2.17.1
> > >