linux-kernel - Re: [PATCH 1/2] power: reset: at91: add sama5d3 reset function

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Date:	Fri, 10 Jul 2015 15:56:52 +0800
From:	Josh Wu <josh.wu@...el.com>
To:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
CC:	Nicolas Ferre <nicolas.ferre@...el.com>,
	<linux-arm-kernel@...ts.infradead.org>,
	Guenter Roeck <linux@...ck-us.net>,
	Wei Yongjun <yongjun_wei@...ndmicro.com.cn>,
	Ben Dooks <ben.dooks@...ethink.co.uk>,
	<linux-kernel@...r.kernel.org>,
	"Krzysztof Kozlowski" <k.kozlowski.k@...il.com>,
	Sebastian Reichel <sre@...nel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	Fabian Frederick <fabf@...net.be>, <linux-pm@...r.kernel.org>,
	Maxime Ripard <maxime.ripard@...e-electrons.com>
Subject: Re: [PATCH 1/2] power: reset: at91: add sama5d3 reset function

Hi, Alexandre

On 7/10/2015 2:03 PM, Alexandre Belloni wrote:
> Hi,
>
> On 09/07/2015 at 18:15:46 +0800, Josh Wu wrote :
>> As since sama5d3, to reset the chip, we don't need to shutdown the ddr
>> controller.
>>
>> So add a new compatible string and new restart function for sama5d3 and
>> later chips. As we don't use sama5d3 ddr controller, so remove it as
>> well.
>>
>> Signed-off-by: Josh Wu <josh.wu@...el.com>
>> Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>
>> ---
>>
>>   drivers/power/reset/at91-reset.c | 30 +++++++++++++++++++++---------
>>   1 file changed, 21 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
>> index 36dc52f..8944b63 100644
>> --- a/drivers/power/reset/at91-reset.c
>> +++ b/drivers/power/reset/at91-reset.c
>> @@ -123,6 +123,14 @@ static int at91sam9g45_restart(struct notifier_block *this, unsigned long mode,
>>   	return NOTIFY_DONE;
>>   }
>>   
>> +static int sama5d3_restart(struct notifier_block *this, unsigned long mode,
>> +			void *cmd)
> Please align that line properly.

Ok.

>
>> +{
>> +	writel(cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST),
>> +				at91_rstc_base);
> That one too.

I'll align them in v2.

>
>> +	return NOTIFY_DONE;
>> +}
>> +
>>   static void __init at91_reset_status(struct platform_device *pdev)
>>   {
>>   	u32 reg = readl(at91_rstc_base + AT91_RSTC_SR);
>> @@ -155,13 +163,13 @@ static void __init at91_reset_status(struct platform_device *pdev)
>>   static const struct of_device_id at91_ramc_of_match[] = {
>>   	{ .compatible = "atmel,at91sam9260-sdramc", },
>>   	{ .compatible = "atmel,at91sam9g45-ddramc", },
>> -	{ .compatible = "atmel,sama5d3-ddramc", },
>>   	{ /* sentinel */ }
>>   };
>>   
>>   static const struct of_device_id at91_reset_of_match[] = {
>>   	{ .compatible = "atmel,at91sam9260-rstc", .data = at91sam9260_restart },
>>   	{ .compatible = "atmel,at91sam9g45-rstc", .data = at91sam9g45_restart },
>> +	{ .compatible = "atmel,sama5d3-rstc", .data = sama5d3_restart },
>>   	{ /* sentinel */ }
>>   };
>>   
>> @@ -181,17 +189,21 @@ static int at91_reset_of_probe(struct platform_device *pdev)
>>   		return -ENODEV;
>>   	}
>>   
>> -	for_each_matching_node(np, at91_ramc_of_match) {
>> -		at91_ramc_base[idx] = of_iomap(np, 0);
>> -		if (!at91_ramc_base[idx]) {
>> -			dev_err(&pdev->dev, "Could not map ram controller address\n");
>> -			return -ENODEV;
>> +	match = of_match_node(at91_reset_of_match, pdev->dev.of_node);
>> +	at91_restart_nb.notifier_call = match->data;
>> +
>> +	if (match->data != sama5d3_restart) {
> This doesn't scale well. I would create a structure with a pointer to
> the restart function and a boolean or a bitfield to store whether the
> workaround is needed. Use that structure in your match data. Then, you
> won't need to reorder anything.

I would agree with Maxime. Currently all latest chip reset function is 
compatible with the atmel,sama5d3-rstc.
So check compatible string is enough for now.
But of cause if we have other incompatible reset in future with new 
chip, the structure like you said is needed.

Thanks.
Best Regards,
Josh Wu
>
>> +		/* we need to shutdown the ddr controller, so get ramc base */
>> +		for_each_matching_node(np, at91_ramc_of_match) {
>> +			at91_ramc_base[idx] = of_iomap(np, 0);
>> +			if (!at91_ramc_base[idx]) {
>> +				dev_err(&pdev->dev, "Could not map ram controller address\n");
>> +				return -ENODEV;
>> +			}
>> +			idx++;
>>   		}
>> -		idx++;
>>   	}
>>   
>> -	match = of_match_node(at91_reset_of_match, pdev->dev.of_node);
>> -	at91_restart_nb.notifier_call = match->data;
>>   	return register_restart_handler(&at91_restart_nb);
>>   }

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