1 /* 2 * Reset driver for Axxia devices 3 * 4 * Copyright (C) 2014 LSI 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 and 8 * only version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 */ 16 #include <linux/init.h> 17 #include <linux/err.h> 18 #include <linux/io.h> 19 #include <linux/kernel.h> 20 #include <linux/mfd/syscon.h> 21 #include <linux/module.h> 22 #include <linux/of.h> 23 #include <linux/platform_device.h> 24 #include <linux/reboot.h> 25 #include <linux/regmap.h> 26 27 #include <asm/system_misc.h> 28 29 30 #define SC_CRIT_WRITE_KEY 0x1000 31 #define SC_LATCH_ON_RESET 0x1004 32 #define SC_RESET_CONTROL 0x1008 33 #define RSTCTL_RST_ZERO (1<<3) 34 #define RSTCTL_RST_FAB (1<<2) 35 #define RSTCTL_RST_CHIP (1<<1) 36 #define RSTCTL_RST_SYS (1<<0) 37 #define SC_EFUSE_INT_STATUS 0x180c 38 #define EFUSE_READ_DONE (1<<31) 39 40 static struct regmap *syscon; 41 42 static void do_axxia_restart(enum reboot_mode reboot_mode, const char *cmd) 43 { 44 /* Access Key (0xab) */ 45 regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab); 46 /* Select internal boot from 0xffff0000 */ 47 regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040); 48 /* Assert ResetReadDone (to avoid hanging in boot ROM) */ 49 regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE); 50 /* Assert chip reset */ 51 regmap_update_bits(syscon, SC_RESET_CONTROL, 52 RSTCTL_RST_CHIP, RSTCTL_RST_CHIP); 53 } 54 55 static int axxia_reset_probe(struct platform_device *pdev) 56 { 57 struct device *dev = &pdev->dev; 58 59 syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon"); 60 if (IS_ERR(syscon)) { 61 pr_err("%s: syscon lookup failed\n", dev->of_node->name); 62 return PTR_ERR(syscon); 63 } 64 65 arm_pm_restart = do_axxia_restart; 66 67 return 0; 68 } 69 70 static const struct of_device_id of_axxia_reset_match[] = { 71 { .compatible = "lsi,axm55xx-reset", }, 72 {}, 73 }; 74 MODULE_DEVICE_TABLE(of, of_axxia_reset_match); 75 76 static struct platform_driver axxia_reset_driver = { 77 .probe = axxia_reset_probe, 78 .driver = { 79 .name = "axxia-reset", 80 .of_match_table = of_match_ptr(of_axxia_reset_match), 81 }, 82 }; 83 84 static int __init axxia_reset_init(void) 85 { 86 return platform_driver_register(&axxia_reset_driver); 87 } 88 device_initcall(axxia_reset_init); 89