Re: [PATCH] watchdog: add davinci watchdog driver

[Antony Pavlov <antonynpavlov@gmail.com>]

On Wed, 22 Apr 2015 12:55:22 +0200
Jan Luebbe <jluebbe@debian.org> wrote:

Can we use this driver for davinci's reset_cpu() reimplementation?

> This driver is based on the Linux driver (v4.0).
> 
> Signed-off-by: Jan Luebbe <jluebbe@debian.org>
> ---
>  drivers/watchdog/Kconfig       |   6 ++
>  drivers/watchdog/Makefile      |   1 +
>  drivers/watchdog/davinci_wdt.c | 172 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 179 insertions(+)
>  create mode 100644 drivers/watchdog/davinci_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 7f7b02e..582c615 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -10,6 +10,12 @@ menuconfig WATCHDOG
>  
>  if WATCHDOG
>  
> +config WATCHDOG_DAVINCI
> +	bool "TI Davinci"
> +	depends on ARCH_DAVINCI
> +	help
> +	  Add support for watchdog on the TI Davinci SoC.
> +
>  config WATCHDOG_MXS28
>  	bool "i.MX28"
>  	depends on ARCH_IMX28
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 865fc47..1e63c49 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -1,4 +1,5 @@
>  obj-$(CONFIG_WATCHDOG) += wd_core.o
> +obj-$(CONFIG_WATCHDOG_DAVINCI) += davinci_wdt.o
>  obj-$(CONFIG_WATCHDOG_MXS28) += im28wd.o
>  obj-$(CONFIG_WATCHDOG_JZ4740) += jz4740.o
>  obj-$(CONFIG_WATCHDOG_IMX_RESET_SOURCE) += imxwd.o
> diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
> new file mode 100644
> index 0000000..17bceb8
> --- /dev/null
> +++ b/drivers/watchdog/davinci_wdt.c
> @@ -0,0 +1,172 @@
> +/*
> + * drivers/char/watchdog/davinci_wdt.c
> + *
> + * Watchdog driver for DaVinci DM644x/DM646x processors
> + *
> + * Copyright (C) 2006-2013 Texas Instruments.
> + * Copyright (C) 2015 Jan Luebbe <jluebbe@debian.org>
> + *
> + * 2007 (c) MontaVista Software, Inc. This file is licensed under
> + * the terms of the GNU General Public License version 2. This program
> + * is licensed "as is" without any warranty of any kind, whether express
> + * or implied.
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <io.h>
> +#include <of.h>
> +#include <errno.h>
> +#include <malloc.h>
> +#include <watchdog.h>
> +
> +#include <linux/clk.h>
> +
> +/* Timer register set definition */
> +#define PID12	(0x0)
> +#define EMUMGT	(0x4)
> +#define TIM12	(0x10)
> +#define TIM34	(0x14)
> +#define PRD12	(0x18)
> +#define PRD34	(0x1C)
> +#define TCR	(0x20)
> +#define TGCR	(0x24)
> +#define WDTCR	(0x28)
> +
> +/* TCR bit definitions */
> +#define ENAMODE12_DISABLED	(0 << 6)
> +#define ENAMODE12_ONESHOT	(1 << 6)
> +#define ENAMODE12_PERIODIC	(2 << 6)
> +
> +/* TGCR bit definitions */
> +#define TIM12RS_UNRESET		(1 << 0)
> +#define TIM34RS_UNRESET		(1 << 1)
> +#define TIMMODE_64BIT_WDOG      (2 << 2)
> +
> +/* WDTCR bit definitions */
> +#define WDEN			(1 << 14)
> +#define WDFLAG			(1 << 15)
> +#define WDKEY_SEQ0		(0xa5c6 << 16)
> +#define WDKEY_SEQ1		(0xda7e << 16)
> +
> +/*
> + * struct to hold data for each WDT device
> + * @wd - hold watchdog device as is in WDT core
> + * @base - base io address of WD device
> + * @clk - source clock of WDT
> + * @timeout - previously configured timeout
> + */
> +struct davinci_wdt {
> +	struct watchdog	wd;
> +	void __iomem	*base;
> +	struct clk	*clk;
> +	unsigned	timeout;
> +};
> +
> +#define to_davinci_wdt(h) container_of(h, struct davinci_wdt, wd)
> +
> +static int davinci_wdt_start(struct watchdog *wd)
> +{
> +	u32 tgcr;
> +	u32 timer_margin;
> +	unsigned long wdt_freq;
> +	struct davinci_wdt *davinci_wdt = to_davinci_wdt(wd);
> +
> +	wdt_freq = clk_get_rate(davinci_wdt->clk);
> +
> +	/* disable, internal clock source */
> +	iowrite32(0, davinci_wdt->base + TCR);
> +	/* reset timer, set mode to 64-bit watchdog, and unreset */
> +	iowrite32(0, davinci_wdt->base + TGCR);
> +	tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
> +	iowrite32(tgcr, davinci_wdt->base + TGCR);
> +	/* clear counter regs */
> +	iowrite32(0, davinci_wdt->base + TIM12);
> +	iowrite32(0, davinci_wdt->base + TIM34);
> +	/* set timeout period */
> +	timer_margin = (((u64)davinci_wdt->timeout * wdt_freq) & 0xffffffff);
> +	iowrite32(timer_margin, davinci_wdt->base + PRD12);
> +	timer_margin = (((u64)davinci_wdt->timeout * wdt_freq) >> 32);
> +	iowrite32(timer_margin, davinci_wdt->base + PRD34);
> +	/* enable run continuously */
> +	iowrite32(ENAMODE12_PERIODIC, davinci_wdt->base + TCR);
> +	/* Once the WDT is in pre-active state write to
> +	 * TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are
> +	 * write protected (except for the WDKEY field)
> +	 */
> +	/* put watchdog in pre-active state */
> +	iowrite32(WDKEY_SEQ0 | WDEN, davinci_wdt->base + WDTCR);
> +	/* put watchdog in active state */
> +	iowrite32(WDKEY_SEQ1 | WDEN, davinci_wdt->base + WDTCR);
> +	return 0;
> +}
> +
> +static int davinci_wdt_ping(struct watchdog *wd)
> +{
> +	struct davinci_wdt *davinci_wdt = to_davinci_wdt(wd);
> +
> +	/* put watchdog in service state */
> +	iowrite32(WDKEY_SEQ0, davinci_wdt->base + WDTCR);
> +	/* put watchdog in active state */
> +	iowrite32(WDKEY_SEQ1, davinci_wdt->base + WDTCR);
> +	return 0;
> +}
> +
> +static int davinci_wdt_set_timeout(struct watchdog *wd, unsigned timeout)
> +{
> +	struct davinci_wdt *davinci_wdt = to_davinci_wdt(wd);
> +
> +	if (!davinci_wdt->timeout) {
> +		davinci_wdt->timeout = timeout;
> +		davinci_wdt_start(wd);
> +	} else {
> +		davinci_wdt_ping(wd);
> +		if (davinci_wdt->timeout != timeout)
> +			pr_warn("watchdog timeout can not be changed (currently %d)\n",
> +				davinci_wdt->timeout);
> +	}
> +
> +	return 0;
> +}
> +
> +static int davinci_wdt_probe(struct device_d *dev)
> +{
> +	int ret = 0;
> +	struct davinci_wdt *davinci_wdt;
> +
> +	davinci_wdt = xzalloc(sizeof(*davinci_wdt));
> +
> +	davinci_wdt->base = dev_request_mem_region(dev, 0);
> +	if (!davinci_wdt->base)
> +		return -ENODEV;
> +
> +	davinci_wdt->clk = clk_get(dev, NULL);
> +	if (WARN_ON(IS_ERR(davinci_wdt->clk)))
> +		return PTR_ERR(davinci_wdt->clk);
> +
> +	clk_enable(davinci_wdt->clk);
> +
> +	davinci_wdt->wd.set_timeout = davinci_wdt_set_timeout;
> +
> +	ret = watchdog_register(&davinci_wdt->wd);
> +	if (ret < 0)
> +		dev_err(dev, "cannot register watchdog device\n");
> +
> +	return ret;
> +}
> +
> +static __maybe_unused struct of_device_id davinci_wdt_of_match[] = {
> +	{ .compatible = "ti,davinci-wdt", },
> +	{},
> +};
> +
> +static struct driver_d platform_wdt_driver = {
> +	.name = "davinci-wdt",
> +	.of_compatible = DRV_OF_COMPAT(davinci_wdt_of_match),
> +	.probe = davinci_wdt_probe,
> +};
> +device_platform_driver(platform_wdt_driver);
> +
> +MODULE_AUTHOR("Texas Instruments");
> +MODULE_DESCRIPTION("DaVinci Watchdog Driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.1.4
> 
> 
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-- 
-- 
Best regards,
  Antony Pavlov

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