// 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 #include #include #include #include #include #include #include #include #include #include #define DRIVER_NAME "turris-mox-rwtm" #define RWTM_DMA_BUFFER_SIZE SZ_4K /* * 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 MOX_ECC_NUMBER_WORDS 17 #define MOX_ECC_NUMBER_LEN (MOX_ECC_NUMBER_WORDS * sizeof(u32)) #define MOX_ECC_SIGNATURE_WORDS (2 * MOX_ECC_NUMBER_WORDS) #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_rwtm { struct mbox_client mbox_client; struct mbox_chan *mbox; 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 */ bool has_board_info; u64 serial_number; int board_version, ram_size; u8 mac_address1[ETH_ALEN], mac_address2[ETH_ALEN]; /* public key burned in eFuse */ bool 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. */ u32 last_sig[MOX_ECC_SIGNATURE_WORDS]; bool last_sig_done; #endif }; static inline struct device *rwtm_dev(struct mox_rwtm *rwtm) { return rwtm->mbox_client.dev; } #define MOX_ATTR_RO(name, format, cat) \ static ssize_t \ name##_show(struct device *dev, struct device_attribute *a, \ char *buf) \ { \ struct mox_rwtm *rwtm = dev_get_drvdata(dev); \ if (!rwtm->has_##cat) \ return -ENODATA; \ return sysfs_emit(buf, format, rwtm->name); \ } \ static DEVICE_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 struct attribute *turris_mox_rwtm_attrs[] = { &dev_attr_serial_number.attr, &dev_attr_board_version.attr, &dev_attr_ram_size.attr, &dev_attr_mac_address1.attr, &dev_attr_mac_address2.attr, &dev_attr_pubkey.attr, NULL }; ATTRIBUTE_GROUPS(turris_mox_rwtm); 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 -EOPNOTSUPP; else if (MBOX_STS_ERROR(retval) != MBOX_STS_SUCCESS) return -EIO; else return MBOX_STS_VALUE(retval); } 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 int mox_rwtm_exec(struct mox_rwtm *rwtm, enum mbox_cmd cmd, struct armada_37xx_rwtm_tx_msg *msg, bool interruptible) { struct armada_37xx_rwtm_tx_msg _msg = {}; int ret; if (!msg) msg = &_msg; msg->command = cmd; ret = mbox_send_message(rwtm->mbox, msg); if (ret < 0) return ret; if (interruptible) { ret = wait_for_completion_interruptible(&rwtm->cmd_done); if (ret < 0) return ret; } else { if (!wait_for_completion_timeout(&rwtm->cmd_done, HZ / 2)) return -ETIMEDOUT; } return mox_get_status(cmd, rwtm->reply.retval); } 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 device *dev = rwtm_dev(rwtm); struct armada_37xx_rwtm_rx_msg *reply = &rwtm->reply; int ret; ret = mox_rwtm_exec(rwtm, MBOX_CMD_BOARD_INFO, NULL, false); if (ret == -ENODATA) { dev_warn(dev, "Board does not have manufacturing information burned!\n"); } else if (ret == -EOPNOTSUPP) { dev_notice(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 = true; 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); } ret = mox_rwtm_exec(rwtm, MBOX_CMD_ECDSA_PUB_KEY, NULL, false); if (ret == -ENODATA) { dev_warn(dev, "Board has no public key burned!\n"); } else if (ret == -EOPNOTSUPP) { dev_notice(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 = true; 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 = { .args = { 1, rwtm->buf_phys, 4 }, }; return mox_rwtm_exec(rwtm, MBOX_CMD_GET_RANDOM, &msg, false); } static int mox_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait) { struct mox_rwtm *rwtm = container_of(rng, struct mox_rwtm, hwrng); struct armada_37xx_rwtm_tx_msg msg = { .args = { 1, rwtm->buf_phys, ALIGN(max, 4) }, }; int ret; max = min(max, RWTM_DMA_BUFFER_SIZE); if (!wait) { if (!mutex_trylock(&rwtm->busy)) return -EBUSY; } else { mutex_lock(&rwtm->busy); } ret = mox_rwtm_exec(rwtm, MBOX_CMD_GET_RANDOM, &msg, true); 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 whole signature, from position 0 */ if (*ppos != 0) return 0; if (len < sizeof(rwtm->last_sig)) return -EINVAL; if (!rwtm->last_sig_done) return -ENODATA; ret = simple_read_from_buffer(buf, len, ppos, rwtm->last_sig, sizeof(rwtm->last_sig)); rwtm->last_sig_done = false; 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_tx_msg msg; loff_t dummy = 0; ssize_t ret; if (len != SHA512_DIGEST_SIZE) 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, sizeof(u32)); ret = simple_write_to_buffer(rwtm->buf + sizeof(u32), SHA512_DIGEST_SIZE, &dummy, buf, len); if (ret < 0) goto unlock_mutex; be32_to_cpu_array(rwtm->buf, rwtm->buf, MOX_ECC_NUMBER_WORDS); msg.args[0] = 1; msg.args[1] = rwtm->buf_phys; msg.args[2] = rwtm->buf_phys + MOX_ECC_NUMBER_LEN; msg.args[3] = rwtm->buf_phys + 2 * MOX_ECC_NUMBER_LEN; ret = mox_rwtm_exec(rwtm, MBOX_CMD_SIGN, &msg, true); if (ret < 0) 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 + MOX_ECC_NUMBER_LEN, sizeof(rwtm->last_sig)); cpu_to_be32_array(rwtm->last_sig, rwtm->last_sig, MOX_ECC_SIGNATURE_WORDS); rwtm->last_sig_done = true; 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, }; static void rwtm_debugfs_release(void *root) { debugfs_remove_recursive(root); } static void rwtm_register_debugfs(struct mox_rwtm *rwtm) { struct dentry *root; root = debugfs_create_dir("turris-mox-rwtm", NULL); debugfs_create_file_unsafe("do_sign", 0600, root, rwtm, &do_sign_fops); devm_add_action_or_reset(rwtm_dev(rwtm), rwtm_debugfs_release, root); } #else static inline void rwtm_register_debugfs(struct mox_rwtm *rwtm) { } #endif static void rwtm_devm_mbox_release(void *mbox) { mbox_free_channel(mbox); } static void rwtm_firmware_symlink_drop(void *parent) { sysfs_remove_link(parent, DRIVER_NAME); } 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->buf = dmam_alloc_coherent(dev, RWTM_DMA_BUFFER_SIZE, &rwtm->buf_phys, GFP_KERNEL); if (!rwtm->buf) return -ENOMEM; platform_set_drvdata(pdev, rwtm); ret = devm_mutex_init(dev, &rwtm->busy); if (ret) return ret; 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)) return dev_err_probe(dev, PTR_ERR(rwtm->mbox), "Cannot request mailbox channel!\n"); ret = devm_add_action_or_reset(dev, rwtm_devm_mbox_release, rwtm->mbox); if (ret) return ret; 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"); return ret; } rwtm->hwrng.name = DRIVER_NAME "_hwrng"; rwtm->hwrng.read = mox_hwrng_read; ret = devm_hwrng_register(dev, &rwtm->hwrng); if (ret) return dev_err_probe(dev, ret, "Cannot register HWRNG!\n"); rwtm_register_debugfs(rwtm); dev_info(dev, "HWRNG successfully registered\n"); /* * For sysfs ABI compatibility, create symlink * /sys/firmware/turris-mox-rwtm to this device's sysfs directory. */ ret = sysfs_create_link(firmware_kobj, &dev->kobj, DRIVER_NAME); if (!ret) devm_add_action_or_reset(dev, rwtm_firmware_symlink_drop, firmware_kobj); 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, .driver = { .name = DRIVER_NAME, .of_match_table = turris_mox_rwtm_match, .dev_groups = turris_mox_rwtm_groups, }, }; module_platform_driver(turris_mox_rwtm_driver); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("Turris Mox rWTM firmware driver"); MODULE_AUTHOR("Marek Behun ");