1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * ARM Secure Monitor Call watchdog driver 4 * Copyright (C) 2022, STMicroelectronics - All Rights Reserved 5 * This file is based on Linux driver drivers/watchdog/arm_smc_wdt.c 6 */ 7 8#define LOG_CATEGORY UCLASS_WDT 9 10#include <dm.h> 11#include <dm/device_compat.h> 12#include <linux/arm-smccc.h> 13#include <linux/psci.h> 14#include <wdt.h> 15 16#define DRV_NAME "arm_smc_wdt" 17 18#define WDT_TIMEOUT_SECS(TIMEOUT) ((TIMEOUT) / 1000) 19 20enum smcwd_call { 21 SMCWD_INIT = 0, 22 SMCWD_SET_TIMEOUT = 1, 23 SMCWD_ENABLE = 2, 24 SMCWD_PET = 3, 25 SMCWD_GET_TIMELEFT = 4, 26}; 27 28struct smcwd_priv_data { 29 u32 smc_id; 30 unsigned int min_timeout; 31 unsigned int max_timeout; 32}; 33 34static int smcwd_call(struct udevice *dev, enum smcwd_call call, 35 unsigned long arg, struct arm_smccc_res *res) 36{ 37 struct smcwd_priv_data *priv = dev_get_priv(dev); 38 struct arm_smccc_res local_res; 39 40 if (!res) 41 res = &local_res; 42 43 arm_smccc_smc(priv->smc_id, call, arg, 0, 0, 0, 0, 0, res); 44 45 if (res->a0 == PSCI_RET_NOT_SUPPORTED) 46 return -ENODEV; 47 if (res->a0 == PSCI_RET_INVALID_PARAMS) 48 return -EINVAL; 49 if (res->a0 != PSCI_RET_SUCCESS) 50 return -EIO; 51 52 return 0; 53} 54 55static int smcwd_reset(struct udevice *dev) 56{ 57 return smcwd_call(dev, SMCWD_PET, 0, NULL); 58} 59 60static int smcwd_stop(struct udevice *dev) 61{ 62 return smcwd_call(dev, SMCWD_ENABLE, 0, NULL); 63} 64 65static int smcwd_start(struct udevice *dev, u64 timeout_ms, ulong flags) 66{ 67 struct smcwd_priv_data *priv = dev_get_priv(dev); 68 u64 timeout_sec = WDT_TIMEOUT_SECS(timeout_ms); 69 int err; 70 71 if (timeout_sec < priv->min_timeout || timeout_sec > priv->max_timeout) { 72 dev_err(dev, "Timeout value not supported\n"); 73 return -EINVAL; 74 } 75 76 err = smcwd_call(dev, SMCWD_SET_TIMEOUT, timeout_sec, NULL); 77 if (err) { 78 dev_err(dev, "Timeout out configuration failed\n"); 79 return err; 80 } 81 82 return smcwd_call(dev, SMCWD_ENABLE, 1, NULL); 83} 84 85static int smcwd_probe(struct udevice *dev) 86{ 87 struct smcwd_priv_data *priv = dev_get_priv(dev); 88 struct arm_smccc_res res; 89 int err; 90 91 priv->smc_id = dev_read_u32_default(dev, "arm,smc-id", 0x82003D06); 92 93 err = smcwd_call(dev, SMCWD_INIT, 0, &res); 94 if (err < 0) { 95 dev_err(dev, "Init failed %i\n", err); 96 return err; 97 } 98 99 priv->min_timeout = res.a1; 100 priv->max_timeout = res.a2; 101 102 return 0; 103} 104 105static const struct wdt_ops smcwd_ops = { 106 .start = smcwd_start, 107 .stop = smcwd_stop, 108 .reset = smcwd_reset, 109}; 110 111static const struct udevice_id smcwd_dt_ids[] = { 112 { .compatible = "arm,smc-wdt" }, 113 {} 114}; 115 116U_BOOT_DRIVER(wdt_sandbox) = { 117 .name = "smcwd", 118 .id = UCLASS_WDT, 119 .of_match = smcwd_dt_ids, 120 .priv_auto = sizeof(struct smcwd_priv_data), 121 .probe = smcwd_probe, 122 .ops = &smcwd_ops, 123}; 124