--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Turris Mox rWTM firmware driver
+ *
+ * Copyright (C) 2019 Marek Behun <marek.behun@nic.cz>
+ */
+
+#include <linux/armada-37xx-rwtm-mailbox.h>
+#include <linux/completion.h>
+#include <linux/dma-mapping.h>
+#include <linux/hw_random.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#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];
+};
+
+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 ||
+ MBOX_STS_ERROR(retval) != MBOX_STS_SUCCESS)
+ return -EIO;
+ else if (MBOX_STS_ERROR(retval) == MBOX_STS_FAIL)
+ return -(int)MBOX_STS_VALUE(retval);
+ 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;
+
+ 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;
+
+ ret = wait_for_completion_timeout(&rwtm->cmd_done, HZ / 2);
+ if (ret < 0)
+ return ret;
+
+ ret = mox_get_status(MBOX_CMD_BOARD_INFO, reply->retval);
+ if (ret < 0 && ret != -ENODATA) {
+ return ret;
+ } else if (ret == -ENODATA) {
+ dev_warn(rwtm->dev,
+ "Board does not have manufacturing information burned!\n");
+ } 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;
+
+ ret = wait_for_completion_timeout(&rwtm->cmd_done, HZ / 2);
+ if (ret < 0)
+ return ret;
+
+ ret = mox_get_status(MBOX_CMD_ECDSA_PUB_KEY, reply->retval);
+ if (ret < 0 && ret != -ENODATA) {
+ return ret;
+ } else if (ret == -ENODATA) {
+ dev_warn(rwtm->dev, "Board has no public key burned!\n");
+ } 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 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;
+}
+
+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);
+
+ 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;
+ }
+
+ init_completion(&rwtm->cmd_done);
+
+ ret = mox_get_board_info(rwtm);
+ if (ret < 0)
+ dev_warn(dev, "Cannot read board information: %i\n", ret);
+
+ 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;
+ }
+
+ 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);
+
+ 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", },
+ { },
+};
+
+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 <marek.behun@nic.cz>");
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