// SPDX-License-Identifier: GPL-2.0+ /* * Mellanox boot control driver * * This driver provides a sysfs interface for systems management * software to manage reset-time actions. * * Copyright (C) 2019 Mellanox Technologies */ #include #include #include #include #include "mlxbf-bootctl.h" #define MLXBF_BOOTCTL_SB_SECURE_MASK 0x03 #define MLXBF_BOOTCTL_SB_TEST_MASK 0x0c #define MLXBF_SB_KEY_NUM 4 /* UUID used to probe ATF service. */ static const char *mlxbf_bootctl_svc_uuid_str = "89c036b4-e7d7-11e6-8797-001aca00bfc4"; struct mlxbf_bootctl_name { u32 value; const char *name; }; static struct mlxbf_bootctl_name boot_names[] = { { MLXBF_BOOTCTL_EXTERNAL, "external" }, { MLXBF_BOOTCTL_EMMC, "emmc" }, { MLNX_BOOTCTL_SWAP_EMMC, "swap_emmc" }, { MLXBF_BOOTCTL_EMMC_LEGACY, "emmc_legacy" }, { MLXBF_BOOTCTL_NONE, "none" }, }; static const char * const mlxbf_bootctl_lifecycle_states[] = { [0] = "Production", [1] = "GA Secured", [2] = "GA Non-Secured", [3] = "RMA", }; /* ARM SMC call which is atomic and no need for lock. */ static int mlxbf_bootctl_smc(unsigned int smc_op, int smc_arg) { struct arm_smccc_res res; arm_smccc_smc(smc_op, smc_arg, 0, 0, 0, 0, 0, 0, &res); return res.a0; } /* Return the action in integer or an error code. */ static int mlxbf_bootctl_reset_action_to_val(const char *action) { int i; for (i = 0; i < ARRAY_SIZE(boot_names); i++) if (sysfs_streq(boot_names[i].name, action)) return boot_names[i].value; return -EINVAL; } /* Return the action in string. */ static const char *mlxbf_bootctl_action_to_string(int action) { int i; for (i = 0; i < ARRAY_SIZE(boot_names); i++) if (boot_names[i].value == action) return boot_names[i].name; return "invalid action"; } static ssize_t post_reset_wdog_show(struct device *dev, struct device_attribute *attr, char *buf) { int ret; ret = mlxbf_bootctl_smc(MLXBF_BOOTCTL_GET_POST_RESET_WDOG, 0); if (ret < 0) return ret; return sprintf(buf, "%d\n", ret); } static ssize_t post_reset_wdog_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { unsigned long value; int ret; ret = kstrtoul(buf, 10, &value); if (ret) return ret; ret = mlxbf_bootctl_smc(MLXBF_BOOTCTL_SET_POST_RESET_WDOG, value); if (ret < 0) return ret; return count; } static ssize_t mlxbf_bootctl_show(int smc_op, char *buf) { int action; action = mlxbf_bootctl_smc(smc_op, 0); if (action < 0) return action; return sprintf(buf, "%s\n", mlxbf_bootctl_action_to_string(action)); } static int mlxbf_bootctl_store(int smc_op, const char *buf, size_t count) { int ret, action; action = mlxbf_bootctl_reset_action_to_val(buf); if (action < 0) return action; ret = mlxbf_bootctl_smc(smc_op, action); if (ret < 0) return ret; return count; } static ssize_t reset_action_show(struct device *dev, struct device_attribute *attr, char *buf) { return mlxbf_bootctl_show(MLXBF_BOOTCTL_GET_RESET_ACTION, buf); } static ssize_t reset_action_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { return mlxbf_bootctl_store(MLXBF_BOOTCTL_SET_RESET_ACTION, buf, count); } static ssize_t second_reset_action_show(struct device *dev, struct device_attribute *attr, char *buf) { return mlxbf_bootctl_show(MLXBF_BOOTCTL_GET_SECOND_RESET_ACTION, buf); } static ssize_t second_reset_action_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { return mlxbf_bootctl_store(MLXBF_BOOTCTL_SET_SECOND_RESET_ACTION, buf, count); } static ssize_t lifecycle_state_show(struct device *dev, struct device_attribute *attr, char *buf) { int lc_state; lc_state = mlxbf_bootctl_smc(MLXBF_BOOTCTL_GET_TBB_FUSE_STATUS, MLXBF_BOOTCTL_FUSE_STATUS_LIFECYCLE); if (lc_state < 0) return lc_state; lc_state &= MLXBF_BOOTCTL_SB_TEST_MASK | MLXBF_BOOTCTL_SB_SECURE_MASK; /* * If the test bits are set, we specify that the current state may be * due to using the test bits. */ if (lc_state & MLXBF_BOOTCTL_SB_TEST_MASK) { lc_state &= MLXBF_BOOTCTL_SB_SECURE_MASK; return sprintf(buf, "%s(test)\n", mlxbf_bootctl_lifecycle_states[lc_state]); } return sprintf(buf, "%s\n", mlxbf_bootctl_lifecycle_states[lc_state]); } static ssize_t secure_boot_fuse_state_show(struct device *dev, struct device_attribute *attr, char *buf) { int burnt, valid, key, key_state, buf_len = 0, upper_key_used = 0; const char *status; key_state = mlxbf_bootctl_smc(MLXBF_BOOTCTL_GET_TBB_FUSE_STATUS, MLXBF_BOOTCTL_FUSE_STATUS_KEYS); if (key_state < 0) return key_state; /* * key_state contains the bits for 4 Key versions, loaded from eFuses * after a hard reset. Lower 4 bits are a thermometer code indicating * key programming has started for key n (0000 = none, 0001 = version 0, * 0011 = version 1, 0111 = version 2, 1111 = version 3). Upper 4 bits * are a thermometer code indicating key programming has completed for * key n (same encodings as the start bits). This allows for detection * of an interruption in the progamming process which has left the key * partially programmed (and thus invalid). The process is to burn the * eFuse for the new key start bit, burn the key eFuses, then burn the * eFuse for the new key complete bit. * * For example 0000_0000: no key valid, 0001_0001: key version 0 valid, * 0011_0011: key 1 version valid, 0011_0111: key version 2 started * programming but did not complete, etc. The most recent key for which * both start and complete bit is set is loaded. On soft reset, this * register is not modified. */ for (key = MLXBF_SB_KEY_NUM - 1; key >= 0; key--) { burnt = key_state & BIT(key); valid = key_state & BIT(key + MLXBF_SB_KEY_NUM); if (burnt && valid) upper_key_used = 1; if (upper_key_used) { if (burnt) status = valid ? "Used" : "Wasted"; else status = valid ? "Invalid" : "Skipped"; } else { if (burnt) status = valid ? "InUse" : "Incomplete"; else status = valid ? "Invalid" : "Free"; } buf_len += sprintf(buf + buf_len, "%d:%s ", key, status); } buf_len += sprintf(buf + buf_len, "\n"); return buf_len; } static DEVICE_ATTR_RW(post_reset_wdog); static DEVICE_ATTR_RW(reset_action); static DEVICE_ATTR_RW(second_reset_action); static DEVICE_ATTR_RO(lifecycle_state); static DEVICE_ATTR_RO(secure_boot_fuse_state); static struct attribute *mlxbf_bootctl_attrs[] = { &dev_attr_post_reset_wdog.attr, &dev_attr_reset_action.attr, &dev_attr_second_reset_action.attr, &dev_attr_lifecycle_state.attr, &dev_attr_secure_boot_fuse_state.attr, NULL }; ATTRIBUTE_GROUPS(mlxbf_bootctl); static const struct acpi_device_id mlxbf_bootctl_acpi_ids[] = { {"MLNXBF04", 0}, {} }; MODULE_DEVICE_TABLE(acpi, mlxbf_bootctl_acpi_ids); static bool mlxbf_bootctl_guid_match(const guid_t *guid, const struct arm_smccc_res *res) { guid_t id = GUID_INIT(res->a0, res->a1, res->a1 >> 16, res->a2, res->a2 >> 8, res->a2 >> 16, res->a2 >> 24, res->a3, res->a3 >> 8, res->a3 >> 16, res->a3 >> 24); return guid_equal(guid, &id); } static int mlxbf_bootctl_probe(struct platform_device *pdev) { struct arm_smccc_res res = { 0 }; guid_t guid; int ret; /* Ensure we have the UUID we expect for this service. */ arm_smccc_smc(MLXBF_BOOTCTL_SIP_SVC_UID, 0, 0, 0, 0, 0, 0, 0, &res); guid_parse(mlxbf_bootctl_svc_uuid_str, &guid); if (!mlxbf_bootctl_guid_match(&guid, &res)) return -ENODEV; /* * When watchdog is used, it sets boot mode to MLXBF_BOOTCTL_SWAP_EMMC * in case of boot failures. However it doesn't clear the state if there * is no failure. Restore the default boot mode here to avoid any * unnecessary boot partition swapping. */ ret = mlxbf_bootctl_smc(MLXBF_BOOTCTL_SET_RESET_ACTION, MLXBF_BOOTCTL_EMMC); if (ret < 0) dev_warn(&pdev->dev, "Unable to reset the EMMC boot mode\n"); return 0; } static struct platform_driver mlxbf_bootctl_driver = { .probe = mlxbf_bootctl_probe, .driver = { .name = "mlxbf-bootctl", .dev_groups = mlxbf_bootctl_groups, .acpi_match_table = mlxbf_bootctl_acpi_ids, } }; module_platform_driver(mlxbf_bootctl_driver); MODULE_DESCRIPTION("Mellanox boot control driver"); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Mellanox Technologies");