// SPDX-License-Identifier: GPL-2.0 // // Copyright (c) 2008 Simtec Electronics // Ben Dooks <ben@simtec.co.uk> // // Copyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com> // // Watchdog reset support for Samsung SoCs. #include <linux/clk.h> #include <linux/err.h> #include <linux/io.h> #include <linux/delay.h> #include <linux/of.h> #include <linux/of_address.h> #define S3C2410_WTCON 0x00 #define S3C2410_WTDAT 0x04 #define S3C2410_WTCNT 0x08 #define S3C2410_WTCON_ENABLE (1 << 5) #define S3C2410_WTCON_DIV16 (0 << 3) #define S3C2410_WTCON_RSTEN (1 << 0) #define S3C2410_WTCON_PRESCALE(x) ((x) << 8) static void __iomem *wdt_base; static struct clk *wdt_clock; void samsung_wdt_reset(void) { if (!wdt_base) { pr_err("%s: wdt reset not initialized\n", __func__); /* delay to allow the serial port to show the message */ mdelay(50); return; } if (!IS_ERR(wdt_clock)) clk_prepare_enable(wdt_clock); /* disable watchdog, to be safe */ __raw_writel(0, wdt_base + S3C2410_WTCON); /* put initial values into count and data */ __raw_writel(0x80, wdt_base + S3C2410_WTCNT); __raw_writel(0x80, wdt_base + S3C2410_WTDAT); /* set the watchdog to go and reset... */ __raw_writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 | S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20), wdt_base + S3C2410_WTCON); /* wait for reset to assert... */ mdelay(500); pr_err("Watchdog reset failed to assert reset\n"); /* delay to allow the serial port to show the message */ mdelay(50); } #ifdef CONFIG_OF static const struct of_device_id s3c2410_wdt_match[] = { { .compatible = "samsung,s3c2410-wdt" }, { .compatible = "samsung,s3c6410-wdt" }, {}, }; void __init samsung_wdt_reset_of_init(void) { struct device_node *np; np = of_find_matching_node(NULL, s3c2410_wdt_match); if (!np) { pr_err("%s: failed to find watchdog node\n", __func__); return; } wdt_base = of_iomap(np, 0); if (!wdt_base) { pr_err("%s: failed to map watchdog registers\n", __func__); return; } wdt_clock = of_clk_get(np, 0); } #endif void __init samsung_wdt_reset_init(void __iomem *base) { wdt_base = base; wdt_clock = clk_get(NULL, "watchdog"); }