1 // SPDX-License-Identifier: GPL-2.0-only
2 // Copyright (C) 2016 Broadcom
3
4 #include <linux/io.h>
5 #include <linux/mod_devicetable.h>
6 #include <linux/platform_device.h>
7 #include <linux/reboot.h>
8
9 #define RSTMGR_REG_WR_ACCESS_OFFSET 0
10 #define RSTMGR_REG_CHIP_SOFT_RST_OFFSET 4
11
12 #define RSTMGR_WR_PASSWORD 0xa5a5
13 #define RSTMGR_WR_PASSWORD_SHIFT 8
14 #define RSTMGR_WR_ACCESS_ENABLE 1
15
16 static void __iomem *kona_reset_base;
17
kona_reset_handler(struct sys_off_data * data)18 static int kona_reset_handler(struct sys_off_data *data)
19 {
20 /*
21 * A soft reset is triggered by writing a 0 to bit 0 of the soft reset
22 * register. To write to that register we must first write the password
23 * and the enable bit in the write access enable register.
24 */
25 writel((RSTMGR_WR_PASSWORD << RSTMGR_WR_PASSWORD_SHIFT) |
26 RSTMGR_WR_ACCESS_ENABLE,
27 kona_reset_base + RSTMGR_REG_WR_ACCESS_OFFSET);
28 writel(0, kona_reset_base + RSTMGR_REG_CHIP_SOFT_RST_OFFSET);
29
30 return NOTIFY_DONE;
31 }
32
kona_reset_probe(struct platform_device * pdev)33 static int kona_reset_probe(struct platform_device *pdev)
34 {
35 kona_reset_base = devm_platform_ioremap_resource(pdev, 0);
36 if (IS_ERR(kona_reset_base))
37 return PTR_ERR(kona_reset_base);
38
39 return devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_RESTART,
40 128, kona_reset_handler, NULL);
41 }
42
43 static const struct of_device_id of_match[] = {
44 { .compatible = "brcm,bcm21664-resetmgr" },
45 {},
46 };
47
48 static struct platform_driver bcm_kona_reset_driver = {
49 .probe = kona_reset_probe,
50 .driver = {
51 .name = "brcm-kona-reset",
52 .of_match_table = of_match,
53 },
54 };
55
56 builtin_platform_driver(bcm_kona_reset_driver);
57