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fa0f8d6700
Add a reset driver for Renesas R-Mobile and SH-Mobile SoCs. It registers a restart handler to trigger a soft power-on reset through the R-Mobile System Controller. The priority of this restart handler is 192, to allow a watchdog driver to use priority 128. Note that we do not use syscon-reboot, as the HPB (Peripheral Bus Bridge) semaphore should be acquired on systems where both the ARM and SH core are in use. The driver can be extended later to support this, when needed. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Sebastian Reichel <sre@kernel.org>
92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
/*
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* Renesas R-Mobile Reset Driver
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*
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* Copyright (C) 2014 Glider bvba
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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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/of_address.h>
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#include <linux/platform_device.h>
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#include <linux/printk.h>
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#include <linux/reboot.h>
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/* SYSC Register Bank 2 */
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#define RESCNT2 0x20 /* Reset Control Register 2 */
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/* Reset Control Register 2 */
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#define RESCNT2_PRES 0x80000000 /* Soft power-on reset */
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static void __iomem *sysc_base2;
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static int rmobile_reset_handler(struct notifier_block *this,
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unsigned long mode, void *cmd)
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{
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pr_debug("%s %lu\n", __func__, mode);
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/* Let's assume we have acquired the HPB semaphore */
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writel(RESCNT2_PRES, sysc_base2 + RESCNT2);
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return NOTIFY_DONE;
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}
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static struct notifier_block rmobile_reset_nb = {
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.notifier_call = rmobile_reset_handler,
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.priority = 192,
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};
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static int rmobile_reset_probe(struct platform_device *pdev)
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{
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int error;
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sysc_base2 = of_iomap(pdev->dev.of_node, 1);
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if (!sysc_base2)
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return -ENODEV;
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error = register_restart_handler(&rmobile_reset_nb);
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if (error) {
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dev_err(&pdev->dev,
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"cannot register restart handler (err=%d)\n", error);
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goto fail_unmap;
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}
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return 0;
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fail_unmap:
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iounmap(sysc_base2);
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return error;
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}
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static int rmobile_reset_remove(struct platform_device *pdev)
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{
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unregister_restart_handler(&rmobile_reset_nb);
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iounmap(sysc_base2);
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return 0;
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}
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static const struct of_device_id rmobile_reset_of_match[] = {
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{ .compatible = "renesas,sysc-rmobile", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, rmobile_reset_of_match);
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static struct platform_driver rmobile_reset_driver = {
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.probe = rmobile_reset_probe,
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.remove = rmobile_reset_remove,
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.driver = {
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.name = "rmobile_reset",
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.of_match_table = rmobile_reset_of_match,
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},
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};
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module_platform_driver(rmobile_reset_driver);
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MODULE_DESCRIPTION("Renesas R-Mobile Reset Driver");
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MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
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MODULE_LICENSE("GPL v2");
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