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author | fishsoupisgood <github@madingley.org> | 2019-04-29 01:17:54 +0100 |
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committer | fishsoupisgood <github@madingley.org> | 2019-05-27 03:43:43 +0100 |
commit | 3f2546b2ef55b661fd8dd69682b38992225e86f6 (patch) | |
tree | 65ca85f13617aee1dce474596800950f266a456c /roms/u-boot/drivers/watchdog/at91sam9_wdt.c | |
download | qemu-master.tar.gz qemu-master.tar.bz2 qemu-master.zip |
Diffstat (limited to 'roms/u-boot/drivers/watchdog/at91sam9_wdt.c')
-rw-r--r-- | roms/u-boot/drivers/watchdog/at91sam9_wdt.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/roms/u-boot/drivers/watchdog/at91sam9_wdt.c b/roms/u-boot/drivers/watchdog/at91sam9_wdt.c new file mode 100644 index 00000000..ffd49a2b --- /dev/null +++ b/roms/u-boot/drivers/watchdog/at91sam9_wdt.c @@ -0,0 +1,77 @@ +/* + * [origin: Linux kernel drivers/watchdog/at91sam9_wdt.c] + * + * Watchdog driver for Atmel AT91SAM9x processors. + * + * Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> + * Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +/* + * The Watchdog Timer Mode Register can be only written to once. If the + * timeout need to be set from U-Boot, be sure that the bootstrap doesn't + * write to this register. Inform Linux to it too + */ + +#include <common.h> +#include <watchdog.h> +#include <asm/arch/hardware.h> +#include <asm/io.h> +#include <asm/arch/at91_wdt.h> + +/* + * AT91SAM9 watchdog runs a 12bit counter @ 256Hz, + * use this to convert a watchdog + * value from/to milliseconds. + */ +#define ms_to_ticks(t) (((t << 8) / 1000) - 1) +#define ticks_to_ms(t) (((t + 1) * 1000) >> 8) + +/* Hardware timeout in seconds */ +#define WDT_HW_TIMEOUT 2 + +/* + * Set the watchdog time interval in 1/256Hz (write-once) + * Counter is 12 bit. + */ +static int at91_wdt_settimeout(unsigned int timeout) +{ + unsigned int reg; + at91_wdt_t *wd = (at91_wdt_t *) ATMEL_BASE_WDT; + + /* Check if disabled */ + if (readl(&wd->mr) & AT91_WDT_MR_WDDIS) { + printf("sorry, watchdog is disabled\n"); + return -1; + } + + /* + * All counting occurs at SLOW_CLOCK / 128 = 256 Hz + * + * Since WDV is a 12-bit counter, the maximum period is + * 4096 / 256 = 16 seconds. + */ + + reg = AT91_WDT_MR_WDRSTEN /* causes watchdog reset */ + | AT91_WDT_MR_WDDBGHLT /* disabled in debug mode */ + | AT91_WDT_MR_WDD(0xfff) /* restart at any time */ + | AT91_WDT_MR_WDV(timeout); /* timer value */ + + writel(reg, &wd->mr); + + return 0; +} + +void hw_watchdog_reset(void) +{ + at91_wdt_t *wd = (at91_wdt_t *) ATMEL_BASE_WDT; + writel(AT91_WDT_CR_WDRSTT | AT91_WDT_CR_KEY, &wd->cr); +} + +void hw_watchdog_init(void) +{ + /* 16 seconds timer, resets enabled */ + at91_wdt_settimeout(ms_to_ticks(WDT_HW_TIMEOUT * 1000)); +} |