173 lines
4.6 KiB
C
173 lines
4.6 KiB
C
/*
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* drivers/char/watchdog/davinci_wdt.c
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*
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* Watchdog driver for DaVinci DM644x/DM646x processors
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*
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* Copyright (C) 2006-2013 Texas Instruments.
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* Copyright (C) 2015 Jan Luebbe <jluebbe@debian.org>
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*
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* 2007 (c) MontaVista Software, Inc. This file is licensed under
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* the terms of the GNU General Public License version 2. This program
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* is licensed "as is" without any warranty of any kind, whether express
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* or implied.
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*/
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#include <common.h>
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#include <init.h>
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#include <io.h>
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#include <of.h>
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#include <errno.h>
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#include <malloc.h>
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#include <watchdog.h>
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#include <linux/clk.h>
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/* Timer register set definition */
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#define PID12 (0x0)
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#define EMUMGT (0x4)
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#define TIM12 (0x10)
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#define TIM34 (0x14)
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#define PRD12 (0x18)
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#define PRD34 (0x1C)
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#define TCR (0x20)
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#define TGCR (0x24)
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#define WDTCR (0x28)
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/* TCR bit definitions */
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#define ENAMODE12_DISABLED (0 << 6)
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#define ENAMODE12_ONESHOT (1 << 6)
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#define ENAMODE12_PERIODIC (2 << 6)
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/* TGCR bit definitions */
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#define TIM12RS_UNRESET (1 << 0)
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#define TIM34RS_UNRESET (1 << 1)
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#define TIMMODE_64BIT_WDOG (2 << 2)
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/* WDTCR bit definitions */
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#define WDEN (1 << 14)
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#define WDFLAG (1 << 15)
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#define WDKEY_SEQ0 (0xa5c6 << 16)
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#define WDKEY_SEQ1 (0xda7e << 16)
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/*
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* struct to hold data for each WDT device
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* @wd - hold watchdog device as is in WDT core
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* @base - base io address of WD device
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* @clk - source clock of WDT
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* @timeout - previously configured timeout
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*/
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struct davinci_wdt {
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struct watchdog wd;
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void __iomem *base;
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struct clk *clk;
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unsigned timeout;
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};
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#define to_davinci_wdt(h) container_of(h, struct davinci_wdt, wd)
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static int davinci_wdt_start(struct watchdog *wd)
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{
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u32 tgcr;
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u32 timer_margin;
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unsigned long wdt_freq;
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struct davinci_wdt *davinci_wdt = to_davinci_wdt(wd);
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wdt_freq = clk_get_rate(davinci_wdt->clk);
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/* disable, internal clock source */
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iowrite32(0, davinci_wdt->base + TCR);
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/* reset timer, set mode to 64-bit watchdog, and unreset */
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iowrite32(0, davinci_wdt->base + TGCR);
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tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
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iowrite32(tgcr, davinci_wdt->base + TGCR);
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/* clear counter regs */
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iowrite32(0, davinci_wdt->base + TIM12);
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iowrite32(0, davinci_wdt->base + TIM34);
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/* set timeout period */
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timer_margin = (((u64)davinci_wdt->timeout * wdt_freq) & 0xffffffff);
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iowrite32(timer_margin, davinci_wdt->base + PRD12);
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timer_margin = (((u64)davinci_wdt->timeout * wdt_freq) >> 32);
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iowrite32(timer_margin, davinci_wdt->base + PRD34);
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/* enable run continuously */
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iowrite32(ENAMODE12_PERIODIC, davinci_wdt->base + TCR);
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/* Once the WDT is in pre-active state write to
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* TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are
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* write protected (except for the WDKEY field)
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*/
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/* put watchdog in pre-active state */
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iowrite32(WDKEY_SEQ0 | WDEN, davinci_wdt->base + WDTCR);
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/* put watchdog in active state */
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iowrite32(WDKEY_SEQ1 | WDEN, davinci_wdt->base + WDTCR);
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return 0;
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}
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static int davinci_wdt_ping(struct watchdog *wd)
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{
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struct davinci_wdt *davinci_wdt = to_davinci_wdt(wd);
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/* put watchdog in service state */
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iowrite32(WDKEY_SEQ0, davinci_wdt->base + WDTCR);
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/* put watchdog in active state */
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iowrite32(WDKEY_SEQ1, davinci_wdt->base + WDTCR);
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return 0;
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}
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static int davinci_wdt_set_timeout(struct watchdog *wd, unsigned timeout)
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{
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struct davinci_wdt *davinci_wdt = to_davinci_wdt(wd);
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if (!davinci_wdt->timeout) {
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davinci_wdt->timeout = timeout;
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davinci_wdt_start(wd);
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} else {
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davinci_wdt_ping(wd);
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if (davinci_wdt->timeout != timeout)
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pr_warn("watchdog timeout can not be changed (currently %d)\n",
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davinci_wdt->timeout);
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}
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return 0;
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}
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static int davinci_wdt_probe(struct device_d *dev)
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{
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int ret = 0;
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struct davinci_wdt *davinci_wdt;
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davinci_wdt = xzalloc(sizeof(*davinci_wdt));
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davinci_wdt->base = dev_request_mem_region(dev, 0);
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if (IS_ERR(davinci_wdt->base))
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return PTR_ERR(davinci_wdt->base);
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davinci_wdt->clk = clk_get(dev, NULL);
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if (WARN_ON(IS_ERR(davinci_wdt->clk)))
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return PTR_ERR(davinci_wdt->clk);
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clk_enable(davinci_wdt->clk);
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davinci_wdt->wd.set_timeout = davinci_wdt_set_timeout;
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ret = watchdog_register(&davinci_wdt->wd);
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if (ret < 0)
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dev_err(dev, "cannot register watchdog device\n");
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return ret;
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}
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static __maybe_unused struct of_device_id davinci_wdt_of_match[] = {
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{ .compatible = "ti,davinci-wdt", },
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{},
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};
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static struct driver_d platform_wdt_driver = {
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.name = "davinci-wdt",
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.of_compatible = DRV_OF_COMPAT(davinci_wdt_of_match),
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.probe = davinci_wdt_probe,
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};
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device_platform_driver(platform_wdt_driver);
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MODULE_AUTHOR("Texas Instruments");
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MODULE_DESCRIPTION("DaVinci Watchdog Driver");
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MODULE_LICENSE("GPL");
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