diff options
Diffstat (limited to 'drivers/platform/mellanox/mlxbf-bootctl.c')
| -rw-r--r-- | drivers/platform/mellanox/mlxbf-bootctl.c | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/drivers/platform/mellanox/mlxbf-bootctl.c b/drivers/platform/mellanox/mlxbf-bootctl.c new file mode 100644 index 000000000000..61753b648506 --- /dev/null +++ b/drivers/platform/mellanox/mlxbf-bootctl.c @@ -0,0 +1,321 @@ +// 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 <linux/acpi.h> +#include <linux/arm-smccc.h> +#include <linux/module.h> +#include <linux/platform_device.h> + +#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", + .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"); |