| Lionel Debieve | 47e022c | 2023-04-14 15:49:15 +0200 | [diff] [blame] | 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 | |
| 20 | enum 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 | |
| 28 | struct smcwd_priv_data { |
| 29 | u32 smc_id; |
| 30 | unsigned int min_timeout; |
| 31 | unsigned int max_timeout; |
| 32 | }; |
| 33 | |
| 34 | static 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 | |
| 55 | static int smcwd_reset(struct udevice *dev) |
| 56 | { |
| 57 | return smcwd_call(dev, SMCWD_PET, 0, NULL); |
| 58 | } |
| 59 | |
| 60 | static int smcwd_stop(struct udevice *dev) |
| 61 | { |
| 62 | return smcwd_call(dev, SMCWD_ENABLE, 0, NULL); |
| 63 | } |
| 64 | |
| 65 | static 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 | |
| 85 | static 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 | |
| 105 | static const struct wdt_ops smcwd_ops = { |
| 106 | .start = smcwd_start, |
| 107 | .stop = smcwd_stop, |
| 108 | .reset = smcwd_reset, |
| 109 | }; |
| 110 | |
| 111 | static const struct udevice_id smcwd_dt_ids[] = { |
| 112 | { .compatible = "arm,smc-wdt" }, |
| 113 | {} |
| 114 | }; |
| 115 | |
| 116 | U_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 | }; |