// SPDX-License-Identifier: GPL-2.0 /* * Turris Mox rWTM firmware driver * * Copyright (C) 2019, 2024 Marek Behún */ #include #include #include #include #include #include #include #include #include #include #include #define DRIVER_NAME "turris-mox-rwtm" /* * The macros and constants below come from Turris Mox's rWTM firmware code. * This firmware is open source and it's sources can be found at * https://gitlab.labs.nic.cz/turris/mox-boot-builder/tree/master/wtmi. */ #define MBOX_STS_SUCCESS (0 << 30) #define MBOX_STS_FAIL (1 << 30) #define MBOX_STS_BADCMD (2 << 30) #define MBOX_STS_ERROR(s) ((s) & (3 << 30)) #define MBOX_STS_VALUE(s) (((s) >> 10) & 0xfffff) #define MBOX_STS_CMD(s) ((s) & 0x3ff) enum mbox_cmd { MBOX_CMD_GET_RANDOM = 1, MBOX_CMD_BOARD_INFO = 2, MBOX_CMD_ECDSA_PUB_KEY = 3, MBOX_CMD_HASH = 4, MBOX_CMD_SIGN = 5, MBOX_CMD_VERIFY = 6, MBOX_CMD_OTP_READ = 7, MBOX_CMD_OTP_WRITE = 8, }; struct mox_kobject; struct mox_rwtm { struct device *dev; struct mbox_client mbox_client; struct mbox_chan *mbox; struct mox_kobject *kobj; struct hwrng hwrng; struct armada_37xx_rwtm_rx_msg reply; void *buf; dma_addr_t buf_phys; struct mutex busy; struct completion cmd_done; /* board information */ int has_board_info; u64 serial_number; int board_version, ram_size; u8 mac_address1[6], mac_address2[6]; /* public key burned in eFuse */ int has_pubkey; u8 pubkey[135]; #ifdef CONFIG_DEBUG_FS /* * Signature process. This is currently done via debugfs, because it * does not conform to the sysfs standard "one file per attribute". * It should be rewritten via crypto API once akcipher API is available * from userspace. */ struct dentry *debugfs_root; u32 last_sig[34]; int last_sig_done; #endif }; struct mox_kobject { struct kobject kobj; struct mox_rwtm *rwtm; }; static inline struct kobject *rwtm_to_kobj(struct mox_rwtm *rwtm) { return &rwtm->kobj->kobj; } static inline struct mox_rwtm *to_rwtm(struct kobject *kobj) { return container_of(kobj, struct mox_kobject, kobj)->rwtm; } static void mox_kobj_release(struct kobject *kobj) { kfree(to_rwtm(kobj)->kobj); } static struct kobj_type mox_kobj_ktype = { .release = mox_kobj_release, .sysfs_ops = &kobj_sysfs_ops, }; static int mox_kobj_create(struct mox_rwtm *rwtm) { rwtm->kobj = kzalloc(sizeof(*rwtm->kobj), GFP_KERNEL); if (!rwtm->kobj) return -ENOMEM; kobject_init(rwtm_to_kobj(rwtm), &mox_kobj_ktype); if (kobject_add(rwtm_to_kobj(rwtm), firmware_kobj, "turris-mox-rwtm")) { kobject_put(rwtm_to_kobj(rwtm)); return -ENXIO; } rwtm->kobj->rwtm = rwtm; return 0; } #define MOX_ATTR_RO(name, format, cat) \ static ssize_t \ name##_show(struct kobject *kobj, struct kobj_attribute *a, \ char *buf) \ { \ struct mox_rwtm *rwtm = to_rwtm(kobj); \ if (!rwtm->has_##cat) \ return -ENODATA; \ return sprintf(buf, format, rwtm->name); \ } \ static struct kobj_attribute mox_attr_##name = __ATTR_RO(name) MOX_ATTR_RO(serial_number, "%016llX\n", board_info); MOX_ATTR_RO(board_version, "%i\n", board_info); MOX_ATTR_RO(ram_size, "%i\n", board_info); MOX_ATTR_RO(mac_address1, "%pM\n", board_info); MOX_ATTR_RO(mac_address2, "%pM\n", board_info); MOX_ATTR_RO(pubkey, "%s\n", pubkey); static int mox_get_status(enum mbox_cmd cmd, u32 retval) { if (MBOX_STS_CMD(retval) != cmd) return -EIO; else if (MBOX_STS_ERROR(retval) == MBOX_STS_FAIL) return -(int)MBOX_STS_VALUE(retval); else if (MBOX_STS_ERROR(retval) == MBOX_STS_BADCMD) return -ENOSYS; else if (MBOX_STS_ERROR(retval) != MBOX_STS_SUCCESS) return -EIO; else return MBOX_STS_VALUE(retval); } static const struct attribute *mox_rwtm_attrs[] = { &mox_attr_serial_number.attr, &mox_attr_board_version.attr, &mox_attr_ram_size.attr, &mox_attr_mac_address1.attr, &mox_attr_mac_address2.attr, &mox_attr_pubkey.attr, NULL }; static void mox_rwtm_rx_callback(struct mbox_client *cl, void *data) { struct mox_rwtm *rwtm = dev_get_drvdata(cl->dev); struct armada_37xx_rwtm_rx_msg *msg = data; if (completion_done(&rwtm->cmd_done)) return; rwtm->reply = *msg; complete(&rwtm->cmd_done); } static void reply_to_mac_addr(u8 *mac, u32 t1, u32 t2) { mac[0] = t1 >> 8; mac[1] = t1; mac[2] = t2 >> 24; mac[3] = t2 >> 16; mac[4] = t2 >> 8; mac[5] = t2; } static int mox_get_board_info(struct mox_rwtm *rwtm) { struct armada_37xx_rwtm_tx_msg msg; struct armada_37xx_rwtm_rx_msg *reply = &rwtm->reply; int ret; msg.command = MBOX_CMD_BOARD_INFO; ret = mbox_send_message(rwtm->mbox, &msg); if (ret < 0) return ret; if (!wait_for_completion_timeout(&rwtm->cmd_done, HZ / 2)) return -ETIMEDOUT; ret = mox_get_status(MBOX_CMD_BOARD_INFO, reply->retval); if (ret == -ENODATA) { dev_warn(rwtm->dev, "Board does not have manufacturing information burned!\n"); } else if (ret == -ENOSYS) { dev_notice(rwtm->dev, "Firmware does not support the BOARD_INFO command\n"); } else if (ret < 0) { return ret; } else { rwtm->serial_number = reply->status[1]; rwtm->serial_number <<= 32; rwtm->serial_number |= reply->status[0]; rwtm->board_version = reply->status[2]; rwtm->ram_size = reply->status[3]; reply_to_mac_addr(rwtm->mac_address1, reply->status[4], reply->status[5]); reply_to_mac_addr(rwtm->mac_address2, reply->status[6], reply->status[7]); rwtm->has_board_info = 1; pr_info("Turris Mox serial number %016llX\n", rwtm->serial_number); pr_info(" board version %i\n", rwtm->board_version); pr_info(" burned RAM size %i MiB\n", rwtm->ram_size); } msg.command = MBOX_CMD_ECDSA_PUB_KEY; ret = mbox_send_message(rwtm->mbox, &msg); if (ret < 0) return ret; if (!wait_for_completion_timeout(&rwtm->cmd_done, HZ / 2)) return -ETIMEDOUT; ret = mox_get_status(MBOX_CMD_ECDSA_PUB_KEY, reply->retval); if (ret == -ENODATA) { dev_warn(rwtm->dev, "Board has no public key burned!\n"); } else if (ret == -ENOSYS) { dev_notice(rwtm->dev, "Firmware does not support the ECDSA_PUB_KEY command\n"); } else if (ret < 0) { return ret; } else { u32 *s = reply->status; rwtm->has_pubkey = 1; sprintf(rwtm->pubkey, "%06x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x", ret, s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7], s[8], s[9], s[10], s[11], s[12], s[13], s[14], s[15]); } return 0; } static int check_get_random_support(struct mox_rwtm *rwtm) { struct armada_37xx_rwtm_tx_msg msg; int ret; msg.command = MBOX_CMD_GET_RANDOM; msg.args[0] = 1; msg.args[1] = rwtm->buf_phys; msg.args[2] = 4; ret = mbox_send_message(rwtm->mbox, &msg); if (ret < 0) return ret; if (!wait_for_completion_timeout(&rwtm->cmd_done, HZ / 2)) return -ETIMEDOUT; return mox_get_status(MBOX_CMD_GET_RANDOM, rwtm->reply.retval); } static int mox_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait) { struct mox_rwtm *rwtm = (struct mox_rwtm *) rng->priv; struct armada_37xx_rwtm_tx_msg msg; int ret; if (max > 4096) max = 4096; msg.command = MBOX_CMD_GET_RANDOM; msg.args[0] = 1; msg.args[1] = rwtm->buf_phys; msg.args[2] = (max + 3) & ~3; if (!wait) { if (!mutex_trylock(&rwtm->busy)) return -EBUSY; } else { mutex_lock(&rwtm->busy); } ret = mbox_send_message(rwtm->mbox, &msg); if (ret < 0) goto unlock_mutex; ret = wait_for_completion_interruptible(&rwtm->cmd_done); if (ret < 0) goto unlock_mutex; ret = mox_get_status(MBOX_CMD_GET_RANDOM, rwtm->reply.retval); if (ret < 0) goto unlock_mutex; memcpy(data, rwtm->buf, max); ret = max; unlock_mutex: mutex_unlock(&rwtm->busy); return ret; } #ifdef CONFIG_DEBUG_FS static int rwtm_debug_open(struct inode *inode, struct file *file) { file->private_data = inode->i_private; return nonseekable_open(inode, file); } static ssize_t do_sign_read(struct file *file, char __user *buf, size_t len, loff_t *ppos) { struct mox_rwtm *rwtm = file->private_data; ssize_t ret; /* only allow one read, of 136 bytes, from position 0 */ if (*ppos != 0) return 0; if (len < 136) return -EINVAL; if (!rwtm->last_sig_done) return -ENODATA; /* 2 arrays of 17 32-bit words are 136 bytes */ ret = simple_read_from_buffer(buf, len, ppos, rwtm->last_sig, 136); rwtm->last_sig_done = 0; return ret; } static ssize_t do_sign_write(struct file *file, const char __user *buf, size_t len, loff_t *ppos) { struct mox_rwtm *rwtm = file->private_data; struct armada_37xx_rwtm_rx_msg *reply = &rwtm->reply; struct armada_37xx_rwtm_tx_msg msg; loff_t dummy = 0; ssize_t ret; /* the input is a SHA-512 hash, so exactly 64 bytes have to be read */ if (len != 64) return -EINVAL; /* if last result is not zero user has not read that information yet */ if (rwtm->last_sig_done) return -EBUSY; if (!mutex_trylock(&rwtm->busy)) return -EBUSY; /* * Here we have to send: * 1. Address of the input to sign. * The input is an array of 17 32-bit words, the first (most * significat) is 0, the rest 16 words are copied from the SHA-512 * hash given by the user and converted from BE to LE. * 2. Address of the buffer where ECDSA signature value R shall be * stored by the rWTM firmware. * 3. Address of the buffer where ECDSA signature value S shall be * stored by the rWTM firmware. */ memset(rwtm->buf, 0, 4); ret = simple_write_to_buffer(rwtm->buf + 4, 64, &dummy, buf, len); if (ret < 0) goto unlock_mutex; be32_to_cpu_array(rwtm->buf, rwtm->buf, 17); msg.command = MBOX_CMD_SIGN; msg.args[0] = 1; msg.args[1] = rwtm->buf_phys; msg.args[2] = rwtm->buf_phys + 68; msg.args[3] = rwtm->buf_phys + 2 * 68; ret = mbox_send_message(rwtm->mbox, &msg); if (ret < 0) goto unlock_mutex; ret = wait_for_completion_interruptible(&rwtm->cmd_done); if (ret < 0) goto unlock_mutex; ret = MBOX_STS_VALUE(reply->retval); if (MBOX_STS_ERROR(reply->retval) != MBOX_STS_SUCCESS) goto unlock_mutex; /* * Here we read the R and S values of the ECDSA signature * computed by the rWTM firmware and convert their words from * LE to BE. */ memcpy(rwtm->last_sig, rwtm->buf + 68, 136); cpu_to_be32_array(rwtm->last_sig, rwtm->last_sig, 34); rwtm->last_sig_done = 1; mutex_unlock(&rwtm->busy); return len; unlock_mutex: mutex_unlock(&rwtm->busy); return ret; } static const struct file_operations do_sign_fops = { .owner = THIS_MODULE, .open = rwtm_debug_open, .read = do_sign_read, .write = do_sign_write, .llseek = no_llseek, }; static int rwtm_register_debugfs(struct mox_rwtm *rwtm) { struct dentry *root, *entry; root = debugfs_create_dir("turris-mox-rwtm", NULL); if (IS_ERR(root)) return PTR_ERR(root); entry = debugfs_create_file_unsafe("do_sign", 0600, root, rwtm, &do_sign_fops); if (IS_ERR(entry)) goto err_remove; rwtm->debugfs_root = root; return 0; err_remove: debugfs_remove_recursive(root); return PTR_ERR(entry); } static void rwtm_unregister_debugfs(struct mox_rwtm *rwtm) { debugfs_remove_recursive(rwtm->debugfs_root); } #else static inline int rwtm_register_debugfs(struct mox_rwtm *rwtm) { return 0; } static inline void rwtm_unregister_debugfs(struct mox_rwtm *rwtm) { } #endif static int turris_mox_rwtm_probe(struct platform_device *pdev) { struct mox_rwtm *rwtm; struct device *dev = &pdev->dev; int ret; rwtm = devm_kzalloc(dev, sizeof(*rwtm), GFP_KERNEL); if (!rwtm) return -ENOMEM; rwtm->dev = dev; rwtm->buf = dmam_alloc_coherent(dev, PAGE_SIZE, &rwtm->buf_phys, GFP_KERNEL); if (!rwtm->buf) return -ENOMEM; ret = mox_kobj_create(rwtm); if (ret < 0) { dev_err(dev, "Cannot create turris-mox-rwtm kobject!\n"); return ret; } ret = sysfs_create_files(rwtm_to_kobj(rwtm), mox_rwtm_attrs); if (ret < 0) { dev_err(dev, "Cannot create sysfs files!\n"); goto put_kobj; } platform_set_drvdata(pdev, rwtm); mutex_init(&rwtm->busy); init_completion(&rwtm->cmd_done); rwtm->mbox_client.dev = dev; rwtm->mbox_client.rx_callback = mox_rwtm_rx_callback; rwtm->mbox = mbox_request_channel(&rwtm->mbox_client, 0); if (IS_ERR(rwtm->mbox)) { ret = PTR_ERR(rwtm->mbox); if (ret != -EPROBE_DEFER) dev_err(dev, "Cannot request mailbox channel: %i\n", ret); goto remove_files; } ret = mox_get_board_info(rwtm); if (ret < 0) dev_warn(dev, "Cannot read board information: %i\n", ret); ret = check_get_random_support(rwtm); if (ret < 0) { dev_notice(dev, "Firmware does not support the GET_RANDOM command\n"); goto free_channel; } rwtm->hwrng.name = DRIVER_NAME "_hwrng"; rwtm->hwrng.read = mox_hwrng_read; rwtm->hwrng.priv = (unsigned long) rwtm; rwtm->hwrng.quality = 1024; ret = devm_hwrng_register(dev, &rwtm->hwrng); if (ret < 0) { dev_err(dev, "Cannot register HWRNG: %i\n", ret); goto free_channel; } ret = rwtm_register_debugfs(rwtm); if (ret < 0) { dev_err(dev, "Failed creating debugfs entries: %i\n", ret); goto free_channel; } dev_info(dev, "HWRNG successfully registered\n"); return 0; free_channel: mbox_free_channel(rwtm->mbox); remove_files: sysfs_remove_files(rwtm_to_kobj(rwtm), mox_rwtm_attrs); put_kobj: kobject_put(rwtm_to_kobj(rwtm)); return ret; } static int turris_mox_rwtm_remove(struct platform_device *pdev) { struct mox_rwtm *rwtm = platform_get_drvdata(pdev); rwtm_unregister_debugfs(rwtm); sysfs_remove_files(rwtm_to_kobj(rwtm), mox_rwtm_attrs); kobject_put(rwtm_to_kobj(rwtm)); mbox_free_channel(rwtm->mbox); return 0; } static const struct of_device_id turris_mox_rwtm_match[] = { { .compatible = "cznic,turris-mox-rwtm", }, { .compatible = "marvell,armada-3700-rwtm-firmware", }, { }, }; MODULE_DEVICE_TABLE(of, turris_mox_rwtm_match); static struct platform_driver turris_mox_rwtm_driver = { .probe = turris_mox_rwtm_probe, .remove = turris_mox_rwtm_remove, .driver = { .name = DRIVER_NAME, .of_match_table = turris_mox_rwtm_match, }, }; module_platform_driver(turris_mox_rwtm_driver); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("Turris Mox rWTM firmware driver"); MODULE_AUTHOR("Marek Behun ");