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kernel add
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/*
* reset controller for CSR SiRFprimaII
*
* Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
*
* Licensed under GPLv2 or later.
*/
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/reset-controller.h>
#include <asm/system_misc.h>
#define SIRFSOC_RSTBIT_NUM 64
static void __iomem *sirfsoc_rstc_base;
static DEFINE_MUTEX(rstc_lock);
static int sirfsoc_reset_module(struct reset_controller_dev *rcdev,
unsigned long sw_reset_idx)
{
u32 reset_bit = sw_reset_idx;
if (reset_bit >= SIRFSOC_RSTBIT_NUM)
return -EINVAL;
mutex_lock(&rstc_lock);
/*
* Writing 1 to this bit resets corresponding block.
* Writing 0 to this bit de-asserts reset signal of the
* corresponding block. datasheet doesn't require explicit
* delay between the set and clear of reset bit. it could
* be shorter if tests pass.
*/
writel(readl(sirfsoc_rstc_base +
(reset_bit / 32) * 4) | (1 << reset_bit),
sirfsoc_rstc_base + (reset_bit / 32) * 4);
msleep(20);
writel(readl(sirfsoc_rstc_base +
(reset_bit / 32) * 4) & ~(1 << reset_bit),
sirfsoc_rstc_base + (reset_bit / 32) * 4);
mutex_unlock(&rstc_lock);
return 0;
}
static struct reset_control_ops sirfsoc_rstc_ops = {
.reset = sirfsoc_reset_module,
};
static struct reset_controller_dev sirfsoc_reset_controller = {
.ops = &sirfsoc_rstc_ops,
.nr_resets = SIRFSOC_RSTBIT_NUM,
};
#define SIRFSOC_SYS_RST_BIT BIT(31)
static void sirfsoc_restart(enum reboot_mode mode, const char *cmd)
{
writel(SIRFSOC_SYS_RST_BIT, sirfsoc_rstc_base);
}
static int sirfsoc_rstc_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
sirfsoc_rstc_base = of_iomap(np, 0);
if (!sirfsoc_rstc_base) {
dev_err(&pdev->dev, "unable to map rstc cpu registers
");
return -ENOMEM;
}
sirfsoc_reset_controller.of_node = np;
arm_pm_restart = sirfsoc_restart;
if (IS_ENABLED(CONFIG_RESET_CONTROLLER))
reset_controller_register(&sirfsoc_reset_controller);
return 0;
}
static const struct of_device_id rstc_ids[] = {
{ .compatible = "sirf,prima2-rstc" },
{},
};
static struct platform_driver sirfsoc_rstc_driver = {
.probe = sirfsoc_rstc_probe,
.driver = {
.name = "sirfsoc_rstc",
.of_match_table = rstc_ids,
},
};
static int __init sirfsoc_rstc_init(void)
{
return platform_driver_register(&sirfsoc_rstc_driver);
}
subsys_initcall(sirfsoc_rstc_init);
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