linux-kernel - Re: [PATCH 4/5] remoteproc: stm32: Allow hold boot management by the SCMI reset controller

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Date:   Tue, 4 Apr 2023 17:15:17 +0200
From:   Arnaud POULIQUEN <arnaud.pouliquen@...s.st.com>
To:     Peng Fan <peng.fan@....com>,
        Bjorn Andersson <andersson@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>
CC:     "linux-remoteproc@...r.kernel.org" <linux-remoteproc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH 4/5] remoteproc: stm32: Allow hold boot management by the
 SCMI reset controller



On 4/4/23 06:55, Peng Fan wrote:
>> Subject: [PATCH 4/5] remoteproc: stm32: Allow hold boot management by
>> the SCMI reset controller
>>
>> The hold boot can be managed by the SCMI controller as a reset.
>> If the "hold_boot" reset is defined in the device tree, use it.
>> Else use the syscon controller directly to access to the register.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
>> ---
>>  drivers/remoteproc/stm32_rproc.c | 34 ++++++++++++++++++++++++++-----
>> -
>>  1 file changed, 28 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/remoteproc/stm32_rproc.c
>> b/drivers/remoteproc/stm32_rproc.c
>> index 4be651e734ee..6b0d8f30a5c7 100644
>> --- a/drivers/remoteproc/stm32_rproc.c
>> +++ b/drivers/remoteproc/stm32_rproc.c
>> @@ -78,6 +78,7 @@ struct stm32_mbox {
>>
>>  struct stm32_rproc {
>>  	struct reset_control *rst;
>> +	struct reset_control *hold_boot_rst;
>>  	struct stm32_syscon hold_boot;
>>  	struct stm32_syscon pdds;
>>  	struct stm32_syscon m4_state;
>> @@ -398,6 +399,14 @@ static int stm32_rproc_set_hold_boot(struct rproc
>> *rproc, bool hold)
>>  	struct stm32_syscon hold_boot = ddata->hold_boot;
>>  	int val, err;
>>
>> +	if (ddata->hold_boot_rst) {
>> +		/* Use the SCMI reset controller */
>> +		if (!hold)
>> +			return reset_control_deassert(ddata-
>>> hold_boot_rst);
>> +		else
>> +			return reset_control_assert(ddata->hold_boot_rst);
>> +	}
>> +
>>  	val = hold ? HOLD_BOOT : RELEASE_BOOT;
>>
>>  	err = regmap_update_bits(hold_boot.map, hold_boot.reg, @@ -
>> 693,16 +702,29 @@ static int stm32_rproc_parse_dt(struct platform_device
>> *pdev,
>>  		dev_info(dev, "wdg irq registered\n");
>>  	}
>>
>> -	ddata->rst = devm_reset_control_get_by_index(dev, 0);
>> +	ddata->rst = devm_reset_control_get(dev, "mcu_rst");
> [Peng Fan] 
> This may break legacy device tree.

That partially true by the fact that I impose the "reset-names" property
(but also suppress the "st,syscfg-tz" property)

But this should not be the case as the arch/arm/boot/dts/stm32mp151.dtsi
is updated in patch 2/5. The DTS files associated to this chip include it.

Thanks,
Arnaud


> 
> Regards,
> Peng.
> 
>>  	if (IS_ERR(ddata->rst))
>>  		return dev_err_probe(dev, PTR_ERR(ddata->rst),
>>  				     "failed to get mcu_reset\n");
>>
>> -	err = stm32_rproc_get_syscon(np, "st,syscfg-holdboot",
>> -				     &ddata->hold_boot);
>> -	if (err) {
>> -		dev_err(dev, "failed to get hold boot\n");
>> -		return err;
>> +	ddata->hold_boot_rst = devm_reset_control_get(dev, "hold_boot");
>> +	if (IS_ERR(ddata->hold_boot_rst)) {
>> +		if (PTR_ERR(ddata->hold_boot_rst) == -EPROBE_DEFER)
>> +			return PTR_ERR(ddata->hold_boot_rst);
>> +		ddata->hold_boot_rst = NULL;
>> +	}
>> +
>> +	if (!ddata->hold_boot_rst) {
>> +		/*
>> +		 * If the hold boot is not managed by the SCMI reset
>> controller,
>> +		 * manage it through the syscon controller
>> +		 */
>> +		err = stm32_rproc_get_syscon(np, "st,syscfg-holdboot",
>> +					     &ddata->hold_boot);
>> +		if (err) {
>> +			dev_err(dev, "failed to get hold boot\n");
>> +			return err;
>> +		}
>>  	}
>>
>>  	err = stm32_rproc_get_syscon(np, "st,syscfg-pdds", &ddata->pdds);
>> --
>> 2.25.1
>