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