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SubjectRe: [PATCH] remoteproc: Add module parameter 'auto_boot'
Hi Mathieu,

Le ven. 20 nov. 2020 à 15:37, Mathieu Poirier
<mathieu.poirier@linaro.org> a écrit :
> Hi Paul,
>
> On Sun, Nov 15, 2020 at 11:50:56AM +0000, Paul Cercueil wrote:
>> Until now the remoteproc core would always default to trying to
>> boot the
>> remote processor at startup. The various remoteproc drivers could
>> however override that setting.
>>
>> Whether or not we want the remote processor to boot, really depends
>> on
>> the nature of the processor itself - a processor built into a WiFi
>> chip
>> will need to be booted for the WiFi hardware to be usable, for
>> instance,
>> but a general-purpose co-processor does not have any predeterminated
>> function, and as such we cannot assume that the OS will want the
>> processor to be booted - yet alone that we have a single do-it-all
>> firmware to load.
>>
>
> If I understand correctly you have various remote processors that use
> the same firmware
> but are serving different purposes - is this correct?

That's the opposite actually. I have one remote processor which is
general-purpose, and as such userspace may or may not want it started
at boot time - depending on what it wants to do with it. The kernel
shouldn't decide itself whether or not the remote processor should be
started, because that's policy.

>
>> Add a 'auto_boot' module parameter that instructs the remoteproc
>> whether
>> or not it should auto-boot the remote processor, which will default
>> to
>> "true" to respect the previous behaviour.
>>
>
> Given that the core can't be a module I wonder if this isn't
> something that
> would be better off in the specific platform driver or the device
> tree... Other
> people might have an opinion as well.

Hardcoded in the platform driver or flagged in the device tree, doesn't
change the fundamental problem - it should be up to the userspace to
decide whether or not the remote processor should boot.

Cheers,
-Paul

>
>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>> ---
>> drivers/remoteproc/remoteproc_core.c | 7 ++++++-
>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/remoteproc/remoteproc_core.c
>> b/drivers/remoteproc/remoteproc_core.c
>> index dab2c0f5caf0..687b1bfd49db 100644
>> --- a/drivers/remoteproc/remoteproc_core.c
>> +++ b/drivers/remoteproc/remoteproc_core.c
>> @@ -44,6 +44,11 @@
>>
>> #define HIGH_BITS_MASK 0xFFFFFFFF00000000ULL
>>
>> +static bool auto_boot = true;
>> +module_param(auto_boot, bool, 0400);
>> +MODULE_PARM_DESC(auto_boot,
>> + "Auto-boot the remote processor [default=true]");
>> +
>> static DEFINE_MUTEX(rproc_list_mutex);
>> static LIST_HEAD(rproc_list);
>> static struct notifier_block rproc_panic_nb;
>> @@ -2176,7 +2181,7 @@ struct rproc *rproc_alloc(struct device *dev,
>> const char *name,
>> return NULL;
>>
>> rproc->priv = &rproc[1];
>> - rproc->auto_boot = true;
>> + rproc->auto_boot = auto_boot;
>> rproc->elf_class = ELFCLASSNONE;
>> rproc->elf_machine = EM_NONE;
>>
>> --
>> 2.29.2
>>


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