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Subject: Re: [PATCH 09/46] watchdog: sa1100: use platform device registration
To:     Arnd Bergmann <arnd@arndb.de>, Daniel Mack <daniel@zonque.org>,
        Haojian Zhuang <haojian.zhuang@gmail.com>,
        Robert Jarzmik <robert.jarzmik@free.fr>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Linus Walleij <linus.walleij@linaro.org>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        linux-watchdog@vger.kernel.org
References: <20191018154052.1276506-1-arnd@arndb.de>
 <20191018154201.1276638-9-arnd@arndb.de>
From:   Guenter Roeck <linux@roeck-us.net>
Message-ID: <bb4713a0-60bd-8d27-874f-e7e3a5adaec8@roeck-us.net>
Date:   Sat, 19 Oct 2019 07:06:48 -0700
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On 10/18/19 8:41 AM, Arnd Bergmann wrote:
> Rather than relying on machine specific headers to
> pass down the reboot status and the register locations,
> use resources and platform_data.
> 
> Aside from this, keep the changes to a minimum.
> 
> Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: linux-watchdog@vger.kernel.org
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   arch/arm/mach-pxa/devices.c               | 11 +++
>   arch/arm/mach-pxa/include/mach/regs-ost.h |  2 +
>   arch/arm/mach-pxa/include/mach/reset.h    |  2 +-
>   arch/arm/mach-pxa/pxa25x.c                |  2 +-
>   arch/arm/mach-pxa/pxa27x.c                |  2 +-
>   arch/arm/mach-pxa/pxa3xx.c                |  2 +-
>   arch/arm/mach-pxa/reset.c                 |  3 -
>   arch/arm/mach-sa1100/generic.c            |  6 +-
>   arch/arm/mach-sa1100/include/mach/reset.h |  1 -
>   drivers/watchdog/sa1100_wdt.c             | 87 ++++++++++++++++-------
>   10 files changed, 83 insertions(+), 35 deletions(-)
> 
> diff --git a/arch/arm/mach-pxa/devices.c b/arch/arm/mach-pxa/devices.c
> index 233035e6a2ff..fb9b4f6d32de 100644
> --- a/arch/arm/mach-pxa/devices.c
> +++ b/arch/arm/mach-pxa/devices.c
> @@ -23,6 +23,8 @@
>   #include <linux/platform_data/mmp_dma.h>
>   #include <linux/platform_data/mtd-nand-pxa3xx.h>
>   
> +#include <mach/regs-ost.h>
> +#include <mach/reset.h>
>   #include "devices.h"
>   #include "generic.h"
>   
> @@ -1110,3 +1112,12 @@ void __init pxa2xx_set_dmac_info(struct mmp_dma_platdata *dma_pdata)
>   {
>   	pxa_register_device(&pxa2xx_pxa_dma, dma_pdata);
>   }
> +
> +void __init pxa_register_wdt(unsigned int reset_status)
> +{
> +	struct resource res = DEFINE_RES_MEM(OST_PHYS, OST_LEN);
> +
> +	reset_status &= RESET_STATUS_WATCHDOG;
> +	platform_device_register_resndata(NULL, "sa1100_wdt", -1, &res, 1,
> +					  &reset_status, sizeof(reset_status));
> +}
> diff --git a/arch/arm/mach-pxa/include/mach/regs-ost.h b/arch/arm/mach-pxa/include/mach/regs-ost.h
> index 109d0ed264df..c8001cfc8d6b 100644
> --- a/arch/arm/mach-pxa/include/mach/regs-ost.h
> +++ b/arch/arm/mach-pxa/include/mach/regs-ost.h
> @@ -7,6 +7,8 @@
>   /*
>    * OS Timer & Match Registers
>    */
> +#define OST_PHYS	0x40A00000
> +#define OST_LEN		0x00000020
>   
>   #define OSMR0		io_p2v(0x40A00000)  /* */
>   #define OSMR1		io_p2v(0x40A00004)  /* */
> diff --git a/arch/arm/mach-pxa/include/mach/reset.h b/arch/arm/mach-pxa/include/mach/reset.h
> index e1c4d100fd45..963dd190bc13 100644
> --- a/arch/arm/mach-pxa/include/mach/reset.h
> +++ b/arch/arm/mach-pxa/include/mach/reset.h
> @@ -8,8 +8,8 @@
>   #define RESET_STATUS_GPIO	(1 << 3)	/* GPIO Reset */
>   #define RESET_STATUS_ALL	(0xf)
>   
> -extern unsigned int reset_status;
>   extern void clear_reset_status(unsigned int mask);
> +extern void pxa_register_wdt(unsigned int reset_status);
>   
>   /**
>    * init_gpio_reset() - register GPIO as reset generator
> diff --git a/arch/arm/mach-pxa/pxa25x.c b/arch/arm/mach-pxa/pxa25x.c
> index 305047ebd2f1..dfc90b41fba3 100644
> --- a/arch/arm/mach-pxa/pxa25x.c
> +++ b/arch/arm/mach-pxa/pxa25x.c
> @@ -240,7 +240,7 @@ static int __init pxa25x_init(void)
>   
>   	if (cpu_is_pxa25x()) {
>   
> -		reset_status = RCSR;
> +		pxa_register_wdt(RCSR);
>   
>   		pxa25x_init_pm();
>   
> diff --git a/arch/arm/mach-pxa/pxa27x.c b/arch/arm/mach-pxa/pxa27x.c
> index a81ac88ecbfd..38fdd22c4dc5 100644
> --- a/arch/arm/mach-pxa/pxa27x.c
> +++ b/arch/arm/mach-pxa/pxa27x.c
> @@ -337,7 +337,7 @@ static int __init pxa27x_init(void)
>   
>   	if (cpu_is_pxa27x()) {
>   
> -		reset_status = RCSR;
> +		pxa_register_wdt(RCSR);
>   
>   		pxa27x_init_pm();
>   
> diff --git a/arch/arm/mach-pxa/pxa3xx.c b/arch/arm/mach-pxa/pxa3xx.c
> index fc84aed99481..7c569fa2a6da 100644
> --- a/arch/arm/mach-pxa/pxa3xx.c
> +++ b/arch/arm/mach-pxa/pxa3xx.c
> @@ -463,7 +463,7 @@ static int __init pxa3xx_init(void)
>   
>   	if (cpu_is_pxa3xx()) {
>   
> -		reset_status = ARSR;
> +		pxa_register_wdt(ARSR);
>   
>   		/*
>   		 * clear RDH bit every time after reset
> diff --git a/arch/arm/mach-pxa/reset.c b/arch/arm/mach-pxa/reset.c
> index af78405aa4e9..fcb791c5ae3e 100644
> --- a/arch/arm/mach-pxa/reset.c
> +++ b/arch/arm/mach-pxa/reset.c
> @@ -11,9 +11,6 @@
>   #include <mach/reset.h>
>   #include <mach/smemc.h>
>   
> -unsigned int reset_status;
> -EXPORT_SYMBOL(reset_status);
> -
>   static void do_hw_reset(void);
>   
>   static int reset_gpio = -1;
> diff --git a/arch/arm/mach-sa1100/generic.c b/arch/arm/mach-sa1100/generic.c
> index 4dfb7554649d..6c21f214cd60 100644
> --- a/arch/arm/mach-sa1100/generic.c
> +++ b/arch/arm/mach-sa1100/generic.c
> @@ -39,9 +39,6 @@
>   #include "generic.h"
>   #include <clocksource/pxa.h>
>   
> -unsigned int reset_status;
> -EXPORT_SYMBOL(reset_status);
> -
>   #define NR_FREQS	16
>   
>   /*
> @@ -319,10 +316,13 @@ static struct platform_device *sa11x0_devices[] __initdata = {
>   
>   static int __init sa1100_init(void)
>   {
> +	struct resource wdt_res = DEFINE_RES_MEM(0x90000000, 0x20);
>   	pm_power_off = sa1100_power_off;
>   
>   	regulator_has_full_constraints();
>   
> +	platform_device_register_simple("sa1100_wdt", -1, &wdt_res, 1);
> +
>   	return platform_add_devices(sa11x0_devices, ARRAY_SIZE(sa11x0_devices));

Wouldn't it be better to add the watchdog device to sa11x0_devices ?

>   }
>   
> diff --git a/arch/arm/mach-sa1100/include/mach/reset.h b/arch/arm/mach-sa1100/include/mach/reset.h
> index 27695650a567..a6723d45ae2a 100644
> --- a/arch/arm/mach-sa1100/include/mach/reset.h
> +++ b/arch/arm/mach-sa1100/include/mach/reset.h
> @@ -10,7 +10,6 @@
>   #define RESET_STATUS_GPIO	(1 << 3)	/* GPIO Reset */
>   #define RESET_STATUS_ALL	(0xf)
>   
> -extern unsigned int reset_status;
>   static inline void clear_reset_status(unsigned int mask)
>   {
>   	RCSR = mask;
> diff --git a/drivers/watchdog/sa1100_wdt.c b/drivers/watchdog/sa1100_wdt.c
> index 0f6ffc1e7f4e..a24d6a07c7a7 100644
> --- a/drivers/watchdog/sa1100_wdt.c
> +++ b/drivers/watchdog/sa1100_wdt.c
> @@ -22,6 +22,7 @@
>   #include <linux/types.h>
>   #include <linux/kernel.h>
>   #include <linux/fs.h>
> +#include <linux/platform_device.h>
>   #include <linux/miscdevice.h>
>   #include <linux/watchdog.h>
>   #include <linux/init.h>
> @@ -30,16 +31,42 @@
>   #include <linux/uaccess.h>
>   #include <linux/timex.h>
>   
> -#ifdef CONFIG_ARCH_PXA
> -#include <mach/regs-ost.h>
> -#endif
> +#define REG_OSMR0  	0x0000  /* OS timer Match Reg. 0 */
> +#define REG_OSMR1  	0x0004  /* OS timer Match Reg. 1 */
> +#define REG_OSMR2  	0x0008  /* OS timer Match Reg. 2 */
> +#define REG_OSMR3  	0x000c  /* OS timer Match Reg. 3 */
> +#define REG_OSCR   	0x0010  /* OS timer Counter Reg. */
> +#define REG_OSSR   	0x0014  /* OS timer Status Reg. */
> +#define REG_OWER   	0x0018  /* OS timer Watch-dog Enable Reg. */
> +#define REG_OIER  	0x001C  /* OS timer Interrupt Enable Reg. */
>   
> -#include <mach/reset.h>
> +#define OSSR_M3		(1 << 3)	/* Match status channel 3 */
> +#define OSSR_M2		(1 << 2)	/* Match status channel 2 */
> +#define OSSR_M1		(1 << 1)	/* Match status channel 1 */
> +#define OSSR_M0		(1 << 0)	/* Match status channel 0 */
> +
> +#define OWER_WME	(1 << 0)	/* Watchdog Match Enable */
> +
> +#define OIER_E3		(1 << 3)	/* Interrupt enable channel 3 */
> +#define OIER_E2		(1 << 2)	/* Interrupt enable channel 2 */
> +#define OIER_E1		(1 << 1)	/* Interrupt enable channel 1 */
> +#define OIER_E0		(1 << 0)	/* Interrupt enable channel 0 */
>   
>   static unsigned long oscr_freq;
>   static unsigned long sa1100wdt_users;
>   static unsigned int pre_margin;
>   static int boot_status;
> +static void __iomem *reg_base;
> +
> +static inline void sa1100_wr(u32 val, u32 offset)
> +{
> +	writel_relaxed(val, reg_base + offset);
> +}
> +
> +static inline u32 sa1100_rd(u32 offset)
> +{
> +	return readl_relaxed(reg_base + offset);
> +}
>   
>   /*
>    *	Allow only one person to hold it open
> @@ -50,10 +77,10 @@ static int sa1100dog_open(struct inode *inode, struct file *file)
>   		return -EBUSY;
>   
>   	/* Activate SA1100 Watchdog timer */
> -	writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
> -	writel_relaxed(OSSR_M3, OSSR);
> -	writel_relaxed(OWER_WME, OWER);
> -	writel_relaxed(readl_relaxed(OIER) | OIER_E3, OIER);
> +	sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
> +	sa1100_wr(OSSR_M3, REG_OSSR);
> +	sa1100_wr(OWER_WME, REG_OWER);
> +	sa1100_wr(sa1100_rd(REG_OIER) | OIER_E3, REG_OIER);
>   	return stream_open(inode, file);
>   }
>   
> @@ -61,7 +88,7 @@ static int sa1100dog_open(struct inode *inode, struct file *file)
>    * The watchdog cannot be disabled.
>    *
>    * Previous comments suggested that turning off the interrupt by
> - * clearing OIER[E3] would prevent the watchdog timing out but this
> + * clearing REG_OIER[E3] would prevent the watchdog timing out but this
>    * does not appear to be true (at least on the PXA255).
>    */
>   static int sa1100dog_release(struct inode *inode, struct file *file)
> @@ -76,7 +103,7 @@ static ssize_t sa1100dog_write(struct file *file, const char __user *data,
>   {
>   	if (len)
>   		/* Refresh OSMR3 timer. */
> -		writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
> +		sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
>   	return len;
>   }
>   
> @@ -110,7 +137,7 @@ static long sa1100dog_ioctl(struct file *file, unsigned int cmd,
>   		break;
>   
>   	case WDIOC_KEEPALIVE:
> -		writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
> +		sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
>   		ret = 0;
>   		break;
>   
> @@ -125,7 +152,7 @@ static long sa1100dog_ioctl(struct file *file, unsigned int cmd,
>   		}
>   
>   		pre_margin = oscr_freq * time;
> -		writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
> +		sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
>   		/*fall through*/
>   
>   	case WDIOC_GETTIMEOUT:
> @@ -150,12 +177,22 @@ static struct miscdevice sa1100dog_miscdev = {
>   	.fops		= &sa1100dog_fops,
>   };
>   
> -static int margin __initdata = 60;		/* (secs) Default is 1 minute */
> +static int margin = 60;		/* (secs) Default is 1 minute */
>   static struct clk *clk;
>   
> -static int __init sa1100dog_init(void)
> +static int sa1100dog_probe(struct platform_device *pdev)
>   {
>   	int ret;
> +	int *platform_data;
> +	struct resource *res;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		return -ENXIO;
> +	reg_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));

	reg_base = devm_platform_ioremap_resource(pdev, 0);

> +	ret = PTR_ERR_OR_ZERO(reg_base);
> +	if (ret)
> +		return ret;
>   
>   	clk = clk_get(NULL, "OSTIMER0");
>   	if (IS_ERR(clk)) {
> @@ -173,13 +210,9 @@ static int __init sa1100dog_init(void)
>   
>   	oscr_freq = clk_get_rate(clk);
>   
> -	/*
> -	 * Read the reset status, and save it for later.  If
> -	 * we suspend, RCSR will be cleared, and the watchdog
> -	 * reset reason will be lost.
> -	 */
> -	boot_status = (reset_status & RESET_STATUS_WATCHDOG) ?
> -				WDIOF_CARDRESET : 0;
> +	platform_data = pdev->dev.platform_data;
> +	if (platform_data && *platform_data)
> +		boot_status = WDIOF_CARDRESET;
>   	pre_margin = oscr_freq * margin;
>   
>   	ret = misc_register(&sa1100dog_miscdev);
> @@ -195,15 +228,21 @@ static int __init sa1100dog_init(void)
>   	return ret;
>   }
>   
> -static void __exit sa1100dog_exit(void)
> +static int sa1100dog_remove(struct platform_device *pdev)
>   {
>   	misc_deregister(&sa1100dog_miscdev);
>   	clk_disable_unprepare(clk);
>   	clk_put(clk);
> +
> +	return 0;
>   }
>   
> -module_init(sa1100dog_init);
> -module_exit(sa1100dog_exit);
> +struct platform_driver sa1100dog_driver = {
> +	.driver.name = "sa1100_wdt",
> +	.probe	  = sa1100dog_probe,
> +	.remove	  = sa1100dog_remove,
> +};
> +module_platform_driver(sa1100dog_driver);
>   
>   MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
>   MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");
>