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