Re: [PATCH v13 4/7] remoteproc: Introduce release_fw optional operation

[Arnaud POULIQUEN <arnaud.pouliquen@foss.st.com>]

On 11/20/24 17:04, Mathieu Poirier wrote:
> On Tue, 19 Nov 2024 at 13:38, Mathieu Poirier
> <mathieu.poirier@linaro.org> wrote:
>>
>> On Tue, 19 Nov 2024 at 11:14, Arnaud POULIQUEN
>> <arnaud.pouliquen@foss.st.com> wrote:
>>>
>>> Hello Mathieu,
>>>
>>> On 11/18/24 18:52, Mathieu Poirier wrote:
>>>> On Mon, Nov 04, 2024 at 02:35:12PM +0100, Arnaud Pouliquen wrote:
>>>>> This patch updates the rproc_ops struct to include an optional
>>>>> release_fw function.
>>>>>
>>>>> The release_fw ops is responsible for releasing the remote processor
>>>>> firmware image. The ops is called in the following cases:
>>>>>
>>>>>  - An error occurs in rproc_start() between the loading of the segments and
>>>>>       the start of the remote processor.
>>>>>  - after stopping the remote processor.
>>>>>
>>>>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>>>>> ---
>>>>> Updates from version V11:
>>>>> - fix typo in @release_fw comment
>>>>> ---
>>>>>  drivers/remoteproc/remoteproc_core.c | 5 +++++
>>>>>  include/linux/remoteproc.h           | 3 +++
>>>>>  2 files changed, 8 insertions(+)
>>>>>
>>>>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
>>>>> index 7694817f25d4..46863e1ca307 100644
>>>>> --- a/drivers/remoteproc/remoteproc_core.c
>>>>> +++ b/drivers/remoteproc/remoteproc_core.c
>>>>> @@ -1258,6 +1258,9 @@ static int rproc_alloc_registered_carveouts(struct rproc *rproc)
>>>>>
>>>>>  static void rproc_release_fw(struct rproc *rproc)
>>>>>  {
>>>>> +    if (rproc->ops->release_fw)
>>>>> +            rproc->ops->release_fw(rproc);
>>>>> +
>>>>>      /* Free the copy of the resource table */
>>>>>      kfree(rproc->cached_table);
>>>>>      rproc->cached_table = NULL;
>>>>> @@ -1377,6 +1380,8 @@ static int rproc_start(struct rproc *rproc, const struct firmware *fw)
>>>>>  unprepare_subdevices:
>>>>>      rproc_unprepare_subdevices(rproc);
>>>>>  reset_table_ptr:
>>>>> +    if (rproc->ops->release_fw)
>>>>> +            rproc->ops->release_fw(rproc);
>>>>>      rproc->table_ptr = rproc->cached_table;
>>>>
>>>> I suggest the following:
>>>>
>>>> 1) Create two new functions, i.e rproc_load_fw() and rproc_release_fw().  The
>>>> only thing those would do is call rproc->ops->load_fw() and
>>>> rproc->ops->release_fw(), if they are present.  When a TEE interface is
>>>> available, ->load_fw() and ->release_fw() become rproc_tee_load_fw() and
>>>> rproc_tee_release_fw().
>>>
>>>
>>> I'm wondering if it should be ->preload_fw() instead of ->load_fw() ops, as the
>>> ->load() op already exists.
>>>
>>
>> I agree that ->load() and ->load_fw() will lead to confusion.  I would
>> support ->preload_fw() but there is no obvious antonyme.
>>
>> Since we already have rproc_ops::prepare() and rproc_prepare_device()
>> I suggest rproc_ops::prepare_fw() and rproc_prepare_fw().  The
>> corollary would be rproc_ops::unprepare_fw() and rproc_unprepare_fm().
>> That said, I'm open to other ideas should you be interested in finding
>> other alternatives.
>>
> 
> Actually...  A better approach might to rename rproc::load to
> rproc::load_segments.  That way we can use rproc::load_fw() and
> rproc_load_fw() without confusion.

Concerning this proposal, please correct me if I'm wrong
- ops::load_segments() would be used for ELF format only as segment notion seems
linked to this format.
- ops:rproc_load_fw should be used for other formats.

The risk is that someone may later come with a requirement to get a resource
table first to configure some memories before loading a non-ELF firmware.


> 
>>>>
>>>> 2) Call rproc_load_fw() in rproc_boot(), just before rproc_fw_boot().  If the
>>>> call to rproc_fw_boot() fails, call rproc_release_fw().
>>>>
>>>> 3) The same logic applies to rproc_boot_recovery(), i.e call rproc_load_fw()
>>>> before rproc_start() and call rproc_release_fw() if rproc_start() fails.
>>>
>>>
>>> I implemented this and I'm currently testing it.
>>> Thise second part requires a few adjustments to work. The ->load() ops needs to
>>> becomes optional to not be called if the "->preload_fw()" is used.
>>>
>>> For that, I propose to return 0 in rproc_load_segments if rproc->ops->load is
>>> NULL and compensate by checking that at least "->preload_fw()" or ->load() is
>>> non-null in rproc_alloc_ops.
>>>
>>
>> I agree.
>>
>>> Thanks,
>>> Arnaud
>>>
>>>
>>>>
>>>> 4) Take rproc_tee_load_fw() out of rproc_tee_parse_fw().  It will now be called
>>>> in rproc_load_fw().
>>>>
>>>> 5) As stated above function rproc_release_fw() now calls rproc_tee_release_fw().
>>>> The former is already called in rproc_shutdown() so we are good in that front.
>>>>
>>>> With the above the cached_table management within the core remains the same and
>>>> we can get rid of patch 3.7.
>>>
>>>>
>>>> Thanks,
>>>> Mathieu
>>>>
>>>>>
>>>>>      return ret;
>>>>> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
>>>>> index 2e0ddcb2d792..08e0187a84d9 100644
>>>>> --- a/include/linux/remoteproc.h
>>>>> +++ b/include/linux/remoteproc.h
>>>>> @@ -381,6 +381,8 @@ enum rsc_handling_status {
>>>>>   * @panic:  optional callback to react to system panic, core will delay
>>>>>   *          panic at least the returned number of milliseconds
>>>>>   * @coredump:         collect firmware dump after the subsystem is shutdown
>>>>> + * @release_fw:     optional function to release the firmware image from ROM memories.
>>>>> + *          This function is called after stopping the remote processor or in case of an error
>>>>>   */
>>>>>  struct rproc_ops {
>>>>>      int (*prepare)(struct rproc *rproc);
>>>>> @@ -403,6 +405,7 @@ struct rproc_ops {
>>>>>      u64 (*get_boot_addr)(struct rproc *rproc, const struct firmware *fw);
>>>>>      unsigned long (*panic)(struct rproc *rproc);
>>>>>      void (*coredump)(struct rproc *rproc);
>>>>> +    void (*release_fw)(struct rproc *rproc);
>>>>>  };
>>>>>
>>>>>  /**
>>>>> --
>>>>> 2.25.1
>>>>>