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

From: Paul Cercueil <paul@crapouillou.net>
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Ohad Ben-Cohen <ohad@wizery.com>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	od@zcrc.me, linux-remoteproc@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 3/5] remoteproc: Add prepare/unprepare callbacks
Date: Wed, 15 Jan 2020 18:15:51 -0300	[thread overview]
Message-ID: <1579122951.3.2@crapouillou.net> (raw)
In-Reply-To: <20191221202039.GG549437@yoga>

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?

In my case, the three memories need the same clock to be enabled.

-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
>> 