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author | Juergen Beisert <jbe@pengutronix.de> | 2012-06-27 16:30:42 +0200 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2012-06-29 15:16:34 +0200 |
commit | 7d6d7c42dacf5ee9db9f25569ff544ae6603ece1 (patch) | |
tree | eb6996b9590a80395a7ad06e24d09f78c4afeefe /drivers/watchdog/im28wd.c | |
parent | 2928591eab21eb6bf4a085f5f19bf87c21ee7866 (diff) | |
download | barebox-7d6d7c42dacf5ee9db9f25569ff544ae6603ece1.tar.gz barebox-7d6d7c42dacf5ee9db9f25569ff544ae6603ece1.tar.xz |
ARM/MXS: add a watchdog driver for i.MX28
Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/watchdog/im28wd.c')
-rw-r--r-- | drivers/watchdog/im28wd.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/drivers/watchdog/im28wd.c b/drivers/watchdog/im28wd.c new file mode 100644 index 0000000000..b016910ec9 --- /dev/null +++ b/drivers/watchdog/im28wd.c @@ -0,0 +1,124 @@ +/* + * (c) 2012 Juergen Beisert <kernel@pengutronix.de> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Note: this driver works for the i.MX28 SoC. It might work for the + * i.MX23 Soc as well, but is not tested yet. + */ + +#include <common.h> +#include <init.h> +#include <io.h> +#include <errno.h> +#include <malloc.h> +#include <watchdog.h> + +#define MXS_RTC_CTRL 0x0 +#define MXS_RTC_SET_ADDR 0x4 +#define MXS_RTC_CLR_ADDR 0x8 +# define MXS_RTC_CTRL_WATCHDOGEN (1 << 4) + +#define MXS_RTC_STAT 0x10 +# define MXS_RTC_STAT_WD_PRESENT (1 << 29) + +#define MXS_RTC_WATCHDOG 0x50 + +#define MXS_RTC_PERSISTENT0 0x60 +/* dubious meaning from inside the SoC's firmware ROM */ +# define MXS_RTC_PERSISTENT0_EXT_RST (1 << 21) +/* dubious meaning from inside the SoC's firmware ROM */ +# define MXS_RTC_PERSISTENT0_THM_RST (1 << 20) + +#define MXS_RTC_PERSISTENT1 0x70 +/* dubious meaning from inside the SoC's firmware ROM */ +# define MXS_RTC_PERSISTENT1_FORCE_UPDATER (1 << 31) + +#define MXS_RTC_DEBUG 0xc0 + +#define WDOG_TICK_RATE 1000 /* the watchdog uses a 1 kHz clock rate */ + +struct imx28_wd { + struct watchdog wd; + void __iomem *regs; +}; + +#define to_imx28_wd(h) container_of(h, struct imx28_wd, wd) + +static int imx28_watchdog_set_timeout(struct watchdog *wd, unsigned timeout) +{ + struct imx28_wd *pwd = (struct imx28_wd *)to_imx28_wd(wd); + void __iomem *base; + + if (timeout > (ULONG_MAX / WDOG_TICK_RATE)) + return -EINVAL; + + if (timeout) { + writel(timeout * WDOG_TICK_RATE, pwd->regs + MXS_RTC_WATCHDOG); + base = pwd->regs + MXS_RTC_SET_ADDR; + } else { + base = pwd->regs + MXS_RTC_CLR_ADDR; + } + writel(MXS_RTC_CTRL_WATCHDOGEN, base + MXS_RTC_CTRL); + writel(MXS_RTC_PERSISTENT1_FORCE_UPDATER, base + MXS_RTC_PERSISTENT1); + + return 0; +} + +static int imx28_wd_probe(struct device_d *dev) +{ + struct imx28_wd *priv; + int rc; + + priv = xzalloc(sizeof(struct imx28_wd)); + priv->regs = dev_request_mem_region(dev, 0); + priv->wd.set_timeout = imx28_watchdog_set_timeout; + + if (!(readl(priv->regs + MXS_RTC_STAT) & MXS_RTC_STAT_WD_PRESENT)) { + rc = -ENODEV; + goto on_error; + } + + /* disable the debug feature to ensure a working WD */ + writel(0x00000000, priv->regs + MXS_RTC_DEBUG); + + rc = watchdog_register(&priv->wd); + if (rc != 0) + goto on_error; + + dev->priv = priv; + return 0; + +on_error: + free(priv); + return rc; +} + +static void imx28_wd_remove(struct device_d *dev) +{ + struct imx28_wd *priv= dev->priv; + watchdog_deregister(&priv->wd); + free(priv); +} + +static struct driver_d imx28_wd_driver = { + .name = "im28wd", + .probe = imx28_wd_probe, + .remove = imx28_wd_remove, +}; + +static int imx28_wd_init(void) +{ + register_driver(&imx28_wd_driver); + return 0; +} + +device_initcall(imx28_wd_init); |