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

Iuliana Prodan
2023-07-18T15:41:05Z

On 7/18/2023 6:23 PM, Mathieu Poirier wrote:
> 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.

This kernel module (imx_dsp_rproc) is used only for DSP.
For M4 core we use imx_rproc.

Iulia

>> 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
>>>>