Re: [PATCH v4 3/5] remoteproc: Add prepare/unprepare callbacks

Arnaud POULIQUEN
2020-01-21T10:24:03Z

Hi Bjorn,Paul,

On 1/20/20 9:19 PM, Bjorn Andersson wrote:
> On Wed 15 Jan 13:15 PST 2020, Paul Cercueil wrote:
>
>> Hi Bjorn,
>>
>>
>> Le sam., déc. 21, 2019 at 12:20, Bjorn Andersson
>> <bjorn.andersson@linaro.org> a écrit :
>>> On Tue 10 Dec 08:40 PST 2019, Paul Cercueil wrote:
>>>
>>>> The .prepare() callback is called before the firmware is loaded to
>>>> memory. This is useful for instance in the case where some setup is
>>>> required for the memory to be accessible.
>>>>
>>>
>>> Would it make sense to somehow tie this prepare/unprepare to the actual
>>> struct rproc_mem_entry that needs the resource enabled?
>>
>> Do you need such granularity?
>>
>
> I don't have such needs, but given some of the memory structure that
> Suman and Loic has been talking about I would expect that such need
> exists
>
>> In my case, the three memories need the same clock to be enabled.
>>
>
> But we can update your driver to associate your one clock with the
> memory objects if/when we end up implementing this later.

IMHO, as mention Fabien the prepare/unprepare should probably not in the stop/start
but in rproc_fw_boot and rproc_resource_cleanup. This should cover more usecases (such as power domain) and
avoid a unprepare/prepare on crash recovery.

Nevertheless I'm wondering if it's more like PM runtime that should be implemented here...?

Regards,
Arnaud

>
> Regards,
> Bjorn
>
>> -Paul
>>
>>
>>>
>>>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>>>> ---
>>>>
>>>> Notes:
>>>> v2-v4: No change
>>>>
>>>> drivers/remoteproc/remoteproc_core.c | 16 +++++++++++++++-
>>>> include/linux/remoteproc.h | 4 ++++
>>>> 2 files changed, 19 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/remoteproc/remoteproc_core.c
>>>> b/drivers/remoteproc/remoteproc_core.c
>>>> index 0a9fc7fdd1c3..3ea5f675a148 100644
>>>> --- a/drivers/remoteproc/remoteproc_core.c
>>>> +++ b/drivers/remoteproc/remoteproc_core.c
>>>> @@ -1299,11 +1299,19 @@ static int rproc_start(struct rproc *rproc,
>>>> const struct firmware *fw)
>>>> struct device *dev = &rproc->dev;
>>>> int ret;
>>>>
>>>> + if (rproc->ops->prepare) {
>>>> + ret = rproc->ops->prepare(rproc);
>>>> + if (ret) {
>>>> + dev_err(dev, "Failed to prepare rproc: %d\n", ret);
>>>> + return ret;
>>>> + }
>>>> + }
>>>> +

>>>> /* load the ELF segments to memory */
>>>> ret = rproc_load_segments(rproc, fw);
>>>> if (ret) {
>>>> dev_err(dev, "Failed to load program segments: %d\n", ret);
>>>> - return ret;
>>>> + goto unprepare_rproc;
>>>> }
>>>>
>>>> /*
>>>> @@ -1354,6 +1362,9 @@ static int rproc_start(struct rproc *rproc,
>>>> const struct firmware *fw)
>>>> rproc_unprepare_subdevices(rproc);
>>>> reset_table_ptr:
>>>> rproc->table_ptr = rproc->cached_table;
>>>> +unprepare_rproc:
>>>> + if (rproc->ops->unprepare)
>>>> + rproc->ops->unprepare(rproc);
>>>>
>>>> return ret;
>>>> }
>>>> @@ -1483,6 +1494,9 @@ static int rproc_stop(struct rproc *rproc,
>>>> bool crashed)
>>>>
>>>> rproc->state = RPROC_OFFLINE;
>>>>
>>>> + if (rproc->ops->unprepare)
>>>> + rproc->ops->unprepare(rproc);
>>>> +
>>>> dev_info(dev, "stopped remote processor %s\n", rproc->name);
>>>>
>>>> return 0;
>>>> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
>>>> index 5f201f0c86c3..a6272d1ba384 100644
>>>> --- a/include/linux/remoteproc.h
>>>> +++ b/include/linux/remoteproc.h
>>>> @@ -355,6 +355,8 @@ enum rsc_handling_status {
>>>>
>>>> /**
>>>> * struct rproc_ops - platform-specific device handlers
>>>> + * @prepare: prepare the device for power up (before the firmware
>>>> is loaded)
>>>> + * @unprepare: unprepare the device after it is stopped
>>>> * @start: power on the device and boot it
>>>> * @stop: power off the device
>>>> * @kick: kick a virtqueue (virtqueue id given as a parameter)
>>>> @@ -371,6 +373,8 @@ enum rsc_handling_status {
>>>> * @get_boot_addr: get boot address to entry point specified in
>>>> firmware
>>>> */
>>>> struct rproc_ops {
>>>> + int (*prepare)(struct rproc *rproc);
>>>> + void (*unprepare)(struct rproc *rproc);
>>>> int (*start)(struct rproc *rproc);
>>>> int (*stop)(struct rproc *rproc);
>>>> void (*kick)(struct rproc *rproc, int vqid);
>>>> --
>>>> 2.24.0
>>>>
>>
>>