Re: [PATCH v2 2/2] watchdog: sama5d4_wdt: addition of sam9x60 compatible watchdog

[<Eugen.Hristev@microchip.com>]

On 29.10.2019 15:28, Guenter Roeck wrote:

> 
> On Mon, Oct 21, 2019 at 09:14:09AM +0000, Eugen.Hristev@microchip.com wrote:
>> From: Eugen Hristev <eugen.hristev@microchip.com>
>>
>> Add support for SAM9X60 WDT into sama5d4_wdt.
>> This means that this driver will have a platform data that will
>> hold differences.
>> Added definitions of different bits.
>> The ops functions will differentiate between the two hardware blocks.
>>
>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
>> ---
>>
>> Hello,
>>
>> This is a rework of the separate sam9x60 watchdog driver into a single driver
>> that supports both hardware blocks (sam9x60 and sama5d4)
>> This was done as suggested on the original patches on the mailing list.
>>
>> Thanks,
>> Eugen
>>
>>   drivers/watchdog/at91sam9_wdt.h |  14 +++++
>>   drivers/watchdog/sama5d4_wdt.c  | 127 +++++++++++++++++++++++++++++++---------
>>   2 files changed, 112 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/watchdog/at91sam9_wdt.h b/drivers/watchdog/at91sam9_wdt.h
>> index 390941c..7a053fd 100644
>> --- a/drivers/watchdog/at91sam9_wdt.h
>> +++ b/drivers/watchdog/at91sam9_wdt.h
>> @@ -20,7 +20,10 @@
>>   #define AT91_WDT_MR		0x04			/* Watchdog Mode Register */
>>   #define		AT91_WDT_WDV		(0xfff << 0)		/* Counter Value */
>>   #define			AT91_WDT_SET_WDV(x)	((x) & AT91_WDT_WDV)
>> +#define		AT91_SAM9X60_PERIODRST	BIT(4)		/* Period Reset */
>> +#define		AT91_SAM9X60_RPTHRST	BIT(5)		/* Minimum Restart Period */
>>   #define		AT91_WDT_WDFIEN		(1     << 12)		/* Fault Interrupt Enable */
>> +#define		AT91_SAM9X60_WDDIS		BIT(12)		/* Disable */
>>   #define		AT91_WDT_WDRSTEN	(1     << 13)		/* Reset Processor */
>>   #define		AT91_WDT_WDRPROC	(1     << 14)		/* Timer Restart */
>>   #define		AT91_WDT_WDDIS		(1     << 15)		/* Watchdog Disable */
>> @@ -33,4 +36,15 @@
>>   #define		AT91_WDT_WDUNF		(1 << 0)		/* Watchdog Underflow */
>>   #define		AT91_WDT_WDERR		(1 << 1)		/* Watchdog Error */
>>   
>> +#define AT91_SAM9X60_VR		0x08			/* Watchdog Timer Value Register */
>> +
>> +#define AT91_SAM9X60_WLR		0x0c
>> +#define		AT91_SAM9X60_COUNTER	(0xfff << 0)		/* Watchdog Period Value */
>> +#define		AT91_SAM9X60_SET_COUNTER(x)	((x) & AT91_SAM9X60_COUNTER)
>> +
>> +#define AT91_SAM9X60_IER		0x14			/* Interrupt Enable Register */
>> +#define		AT91_SAM9X60_PERINT		BIT(0)		/* Period Interrupt Enable */
>> +#define AT91_SAM9X60_IDR		0x18			/* Interrupt Disable Register */
>> +#define AT91_SAM9X60_ISR		0x1c			/* Interrupt Status Register */
>> +
> 
> Those tabs are getting messy, and the mix of BIT() and shift is messy too.
> Mind cleaning it up a bit ? Especially, two tabs after #define doesn't really
> add value (use two spaces), and use BIT() throughout or not at all.
> 
>>   #endif
>> diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c
>> index d193a60..b92afd7 100644
>> --- a/drivers/watchdog/sama5d4_wdt.c
>> +++ b/drivers/watchdog/sama5d4_wdt.c
>> @@ -2,7 +2,7 @@
>>   /*
>>    * Driver for Atmel SAMA5D4 Watchdog Timer
>>    *
>> - * Copyright (C) 2015 Atmel Corporation
>> + * Copyright (C) 2015-2019 Microchip Technology Inc. and its subsidiaries
>>    */
>>   
>>   #include <linux/delay.h>
>> @@ -11,6 +11,7 @@
>>   #include <linux/kernel.h>
>>   #include <linux/module.h>
>>   #include <linux/of.h>
>> +#include <linux/of_device.h>
>>   #include <linux/of_irq.h>
>>   #include <linux/platform_device.h>
>>   #include <linux/reboot.h>
>> @@ -25,11 +26,18 @@
>>   
>>   #define WDT_SEC2TICKS(s)	((s) ? (((s) << 8) - 1) : 0)
>>   
>> +struct sama5d4_wdt_data {
>> +	const unsigned int		sam9x60_support;
>> +};
>> +
>>   struct sama5d4_wdt {
>> -	struct watchdog_device	wdd;
>> -	void __iomem		*reg_base;
>> -	u32			mr;
>> -	unsigned long		last_ping;
>> +	struct watchdog_device		wdd;
>> +	const struct sama5d4_wdt_data	*data;
>> +	void __iomem			*reg_base;
>> +	u32				mr;
>> +	u32				ir;
>> +	unsigned long			last_ping;
>> +	unsigned int			need_irq:1;
> 
> This can be a bool. Making it a bit just adds complexity to the code.
> 
>>   };
>>   
>>   static int wdt_timeout;
>> @@ -78,7 +86,12 @@ static int sama5d4_wdt_start(struct watchdog_device *wdd)
>>   {
>>   	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
>>   
>> -	wdt->mr &= ~AT91_WDT_WDDIS;
>> +	if (wdt->data->sam9x60_support) {
>> +		writel_relaxed(wdt->ir, wdt->reg_base + AT91_SAM9X60_IER);
>> +		wdt->mr &= ~AT91_SAM9X60_WDDIS;
>> +	} else {
>> +		wdt->mr &= ~AT91_WDT_WDDIS;
>> +	}
>>   	wdt_write(wdt, AT91_WDT_MR, wdt->mr);
>>   
>>   	return 0;
>> @@ -88,7 +101,12 @@ static int sama5d4_wdt_stop(struct watchdog_device *wdd)
>>   {
>>   	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
>>   
>> -	wdt->mr |= AT91_WDT_WDDIS;
>> +	if (wdt->data->sam9x60_support) {
>> +		writel_relaxed(wdt->ir, wdt->reg_base + AT91_SAM9X60_IDR);
>> +		wdt->mr |= AT91_SAM9X60_WDDIS;
>> +	} else {
>> +		wdt->mr |= AT91_WDT_WDDIS;
>> +	}
>>   	wdt_write(wdt, AT91_WDT_MR, wdt->mr);
>>   
>>   	return 0;
>> @@ -109,6 +127,14 @@ static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
>>   	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
>>   	u32 value = WDT_SEC2TICKS(timeout);
>>   
>> +	if (wdt->data->sam9x60_support) {
>> +		wdt_write(wdt, AT91_SAM9X60_WLR,
>> +			  AT91_SAM9X60_SET_COUNTER(value));
>> +
>> +		wdd->timeout = timeout;
>> +		return 0;
>> +	}
>> +
>>   	wdt->mr &= ~AT91_WDT_WDV;
>>   	wdt->mr |= AT91_WDT_SET_WDV(value);
>>   
>> @@ -143,8 +169,14 @@ static const struct watchdog_ops sama5d4_wdt_ops = {
>>   static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id)
>>   {
>>   	struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id);
>> +	u32 reg;
>>   
>> -	if (wdt_read(wdt, AT91_WDT_SR)) {
>> +	if (wdt->data->sam9x60_support)
>> +		reg = wdt_read(wdt, AT91_SAM9X60_ISR);
>> +	else
>> +		reg = wdt_read(wdt, AT91_WDT_SR);
>> +
>> +	if (reg) {
>>   		pr_crit("Atmel Watchdog Software Reset\n");
>>   		emergency_restart();
>>   		pr_crit("Reboot didn't succeed\n");
>> @@ -157,13 +189,14 @@ static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
>>   {
>>   	const char *tmp;
>>   
>> -	wdt->mr = AT91_WDT_WDDIS;
>> +	if (wdt->data->sam9x60_support)
>> +		wdt->mr = AT91_SAM9X60_WDDIS;
>> +	else
>> +		wdt->mr = AT91_WDT_WDDIS;
>>   
>>   	if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
>>   	    !strcmp(tmp, "software"))
>> -		wdt->mr |= AT91_WDT_WDFIEN;
>> -	else
>> -		wdt->mr |= AT91_WDT_WDRSTEN;
>> +		wdt->need_irq = 1;
>>   
>>   	if (of_property_read_bool(np, "atmel,idle-halt"))
>>   		wdt->mr |= AT91_WDT_WDIDLEHLT;
>> @@ -176,21 +209,46 @@ static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
>>   
>>   static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
>>   {
>> -	u32 reg;
>> +	u32 reg, val;
>> +
>> +	val = WDT_SEC2TICKS(WDT_DEFAULT_TIMEOUT);
>>   	/*
>>   	 * When booting and resuming, the bootloader may have changed the
>>   	 * watchdog configuration.
>>   	 * If the watchdog is already running, we can safely update it.
>>   	 * Else, we have to disable it properly.
>>   	 */
>> -	if (wdt_enabled) {
>> -		wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr);
>> -	} else {
>> +	if (!wdt_enabled) {
>>   		reg = wdt_read(wdt, AT91_WDT_MR);
>> -		if (!(reg & AT91_WDT_WDDIS))
>> +		if (wdt->data->sam9x60_support && (!(reg & AT91_SAM9X60_WDDIS)))
>> +			wdt_write_nosleep(wdt, AT91_WDT_MR,
>> +					  reg | AT91_SAM9X60_WDDIS);
>> +		else if (!wdt->data->sam9x60_support &&
>> +			 (!(reg & AT91_WDT_WDDIS)))
>>   			wdt_write_nosleep(wdt, AT91_WDT_MR,
>>   					  reg | AT91_WDT_WDDIS);
>>   	}
>> +
>> +	if (wdt->data->sam9x60_support) {
>> +		if (wdt->need_irq)
>> +			wdt->ir = AT91_SAM9X60_PERINT;
>> +		else
>> +			wdt->mr |= AT91_SAM9X60_PERIODRST;
>> +
>> +		wdt_write(wdt, AT91_SAM9X60_IER, wdt->ir);
>> +		wdt_write(wdt, AT91_SAM9X60_WLR, AT91_SAM9X60_SET_COUNTER(val));
>> +	} else {
>> +		wdt->mr |= AT91_WDT_SET_WDD(WDT_SEC2TICKS(MAX_WDT_TIMEOUT));
>> +		wdt->mr |= AT91_WDT_SET_WDV(val);
>> +
>> +		if (wdt->need_irq)
>> +			wdt->mr |= AT91_WDT_WDFIEN;
>> +		else
>> +			wdt->mr |= AT91_WDT_WDRSTEN;
>> +	}
>> +
>> +	wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr);
>> +
>>   	return 0;
>>   }
>>   
>> @@ -201,13 +259,14 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
>>   	struct sama5d4_wdt *wdt;
>>   	void __iomem *regs;
>>   	u32 irq = 0;
>> -	u32 timeout;
>>   	int ret;
>>   
>>   	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>>   	if (!wdt)
>>   		return -ENOMEM;
>>   
>> +	wdt->data = of_device_get_match_data(&pdev->dev);
>> +
>>   	wdd = &wdt->wdd;
>>   	wdd->timeout = WDT_DEFAULT_TIMEOUT;
>>   	wdd->info = &sama5d4_wdt_info;
>> @@ -224,15 +283,17 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
>>   
>>   	wdt->reg_base = regs;
>>   
>> -	irq = irq_of_parse_and_map(dev->of_node, 0);
>> -	if (!irq)
>> -		dev_warn(dev, "failed to get IRQ from DT\n");
>> -
>>   	ret = of_sama5d4_wdt_init(dev->of_node, wdt);
>>   	if (ret)
>>   		return ret;
>>   
>> -	if ((wdt->mr & AT91_WDT_WDFIEN) && irq) {
>> +	irq = irq_of_parse_and_map(dev->of_node, 0);
>> +	if (!irq) {
>> +		dev_warn(dev, "failed to get IRQ from DT\n");
>> +		wdt->need_irq = 0;
> 
> Does it make sense to ignore that ?

Hi Guenter,

Can you detail what exactly is ignored ?

> 
>> +	}
>> +
>> +	if (wdt->need_irq) {
>>   		ret = devm_request_irq(dev, irq, sama5d4_wdt_irq_handler,
>>   				       IRQF_SHARED | IRQF_IRQPOLL |
>>   				       IRQF_NO_SUSPEND, pdev->name, pdev);
>> @@ -244,11 +305,6 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
>>   
>>   	watchdog_init_timeout(wdd, wdt_timeout, dev);
>>   
>> -	timeout = WDT_SEC2TICKS(wdd->timeout);
>> -
>> -	wdt->mr |= AT91_WDT_SET_WDD(WDT_SEC2TICKS(MAX_WDT_TIMEOUT));
>> -	wdt->mr |= AT91_WDT_SET_WDV(timeout);
>> -
>>   	ret = sama5d4_wdt_init(wdt);
>>   	if (ret)
>>   		return ret;
>> @@ -268,8 +324,21 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
>>   	return 0;
>>   }
>>   
>> +static struct sama5d4_wdt_data sama5d4_config;
>> +
>> +static struct sama5d4_wdt_data sam9x60_config = {
>> +	.sam9x60_support = 1,
>> +};
> 
> Unless there is reason to believe that there will be other
> configuration data, please just assign the flag value directly
> to .data and add a variable to struct sama5d4_wdt to access it.
> Please make that variable a bool.

There will be more configuration data for future products, but not at 
this moment. Do the change or keep it this way ?

I will do the other changes as requested.
Thanks for reviewing,

Eugen
> 
>> +
>>   static const struct of_device_id sama5d4_wdt_of_match[] = {
>> -	{ .compatible = "atmel,sama5d4-wdt", },
>> +	{
>> +		.compatible = "atmel,sama5d4-wdt",
>> +		.data = &sama5d4_config,
>> +	},
>> +	{
>> +		.compatible = "microchip,sam9x60-wdt",
>> +		.data = &sam9x60_config,
>> +	},
>>   	{ }
>>   };
>>   MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);
> 
>