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