176 lines
4.2 KiB
C
176 lines
4.2 KiB
C
/*
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* TI keystone reboot driver
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*
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* Copyright (C) 2014 Texas Instruments Incorporated. http://www.ti.com/
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*
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* Author: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/regmap.h>
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#include <linux/mfd/syscon.h>
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#include <linux/of_platform.h>
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#define RSTYPE_RG 0x0
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#define RSCTRL_RG 0x4
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#define RSCFG_RG 0x8
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#define RSISO_RG 0xc
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#define RSCTRL_KEY_MASK 0x0000ffff
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#define RSCTRL_RESET_MASK BIT(16)
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#define RSCTRL_KEY 0x5a69
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#define RSMUX_OMODE_MASK 0xe
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#define RSMUX_OMODE_RESET_ON 0xa
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#define RSMUX_OMODE_RESET_OFF 0x0
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#define RSMUX_LOCK_MASK 0x1
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#define RSMUX_LOCK_SET 0x1
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#define RSCFG_RSTYPE_SOFT 0x300f
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#define RSCFG_RSTYPE_HARD 0x0
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#define WDT_MUX_NUMBER 0x4
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static int rspll_offset;
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static struct regmap *pllctrl_regs;
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/**
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* rsctrl_enable_rspll_write - enable access to RSCTRL, RSCFG
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* To be able to access to RSCTRL, RSCFG registers
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* we have to write a key before
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*/
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static inline int rsctrl_enable_rspll_write(void)
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{
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return regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,
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RSCTRL_KEY_MASK, RSCTRL_KEY);
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}
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static int rsctrl_restart_handler(struct notifier_block *this,
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unsigned long mode, void *cmd)
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{
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/* enable write access to RSTCTRL */
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rsctrl_enable_rspll_write();
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/* reset the SOC */
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regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,
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RSCTRL_RESET_MASK, 0);
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return NOTIFY_DONE;
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}
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static struct notifier_block rsctrl_restart_nb = {
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.notifier_call = rsctrl_restart_handler,
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.priority = 128,
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};
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static const struct of_device_id rsctrl_of_match[] = {
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{.compatible = "ti,keystone-reset", },
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{},
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};
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static int rsctrl_probe(struct platform_device *pdev)
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{
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int i;
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int ret;
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u32 val;
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unsigned int rg;
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u32 rsmux_offset;
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struct regmap *devctrl_regs;
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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if (!np)
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return -ENODEV;
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/* get regmaps */
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pllctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-pll");
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if (IS_ERR(pllctrl_regs))
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return PTR_ERR(pllctrl_regs);
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devctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev");
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if (IS_ERR(devctrl_regs))
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return PTR_ERR(devctrl_regs);
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ret = of_property_read_u32_index(np, "ti,syscon-pll", 1, &rspll_offset);
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if (ret) {
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dev_err(dev, "couldn't read the reset pll offset!\n");
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return -EINVAL;
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}
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ret = of_property_read_u32_index(np, "ti,syscon-dev", 1, &rsmux_offset);
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if (ret) {
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dev_err(dev, "couldn't read the rsmux offset!\n");
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return -EINVAL;
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}
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/* set soft/hard reset */
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val = of_property_read_bool(np, "ti,soft-reset");
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val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD;
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ret = rsctrl_enable_rspll_write();
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if (ret)
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return ret;
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ret = regmap_write(pllctrl_regs, rspll_offset + RSCFG_RG, val);
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if (ret)
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return ret;
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/* disable a reset isolation for all module clocks */
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ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0);
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if (ret)
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return ret;
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/* enable a reset for watchdogs from wdt-list */
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for (i = 0; i < WDT_MUX_NUMBER; i++) {
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ret = of_property_read_u32_index(np, "ti,wdt-list", i, &val);
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if (ret == -EOVERFLOW && !i) {
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dev_err(dev, "ti,wdt-list property has to contain at"
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"least one entry\n");
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return -EINVAL;
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} else if (ret) {
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break;
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}
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if (val >= WDT_MUX_NUMBER) {
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dev_err(dev, "ti,wdt-list property can contain "
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"only numbers < 4\n");
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return -EINVAL;
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}
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rg = rsmux_offset + val * 4;
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ret = regmap_update_bits(devctrl_regs, rg, RSMUX_OMODE_MASK,
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RSMUX_OMODE_RESET_ON |
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RSMUX_LOCK_SET);
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if (ret)
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return ret;
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}
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ret = register_restart_handler(&rsctrl_restart_nb);
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if (ret)
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dev_err(dev, "cannot register restart handler (err=%d)\n", ret);
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return ret;
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}
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static struct platform_driver rsctrl_driver = {
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.probe = rsctrl_probe,
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.driver = {
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.name = KBUILD_MODNAME,
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.of_match_table = rsctrl_of_match,
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},
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};
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module_platform_driver(rsctrl_driver);
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MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>");
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MODULE_DESCRIPTION("Texas Instruments keystone reset driver");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:" KBUILD_MODNAME);
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