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550 lines
13 KiB
550 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Turris Mox rWTM firmware driver |
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* |
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* Copyright (C) 2019 Marek Behún <[email protected]> |
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*/ |
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|
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#include <linux/armada-37xx-rwtm-mailbox.h> |
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#include <linux/completion.h> |
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#include <linux/debugfs.h> |
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#include <linux/dma-mapping.h> |
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#include <linux/hw_random.h> |
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#include <linux/mailbox_client.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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#define DRIVER_NAME "turris-mox-rwtm" |
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|
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/* |
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* The macros and constants below come from Turris Mox's rWTM firmware code. |
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* This firmware is open source and it's sources can be found at |
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* https://gitlab.labs.nic.cz/turris/mox-boot-builder/tree/master/wtmi. |
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*/ |
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#define MBOX_STS_SUCCESS (0 << 30) |
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#define MBOX_STS_FAIL (1 << 30) |
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#define MBOX_STS_BADCMD (2 << 30) |
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#define MBOX_STS_ERROR(s) ((s) & (3 << 30)) |
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#define MBOX_STS_VALUE(s) (((s) >> 10) & 0xfffff) |
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#define MBOX_STS_CMD(s) ((s) & 0x3ff) |
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enum mbox_cmd { |
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MBOX_CMD_GET_RANDOM = 1, |
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MBOX_CMD_BOARD_INFO = 2, |
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MBOX_CMD_ECDSA_PUB_KEY = 3, |
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MBOX_CMD_HASH = 4, |
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MBOX_CMD_SIGN = 5, |
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MBOX_CMD_VERIFY = 6, |
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MBOX_CMD_OTP_READ = 7, |
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MBOX_CMD_OTP_WRITE = 8, |
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}; |
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struct mox_kobject; |
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struct mox_rwtm { |
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struct device *dev; |
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struct mbox_client mbox_client; |
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struct mbox_chan *mbox; |
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struct mox_kobject *kobj; |
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struct hwrng hwrng; |
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struct armada_37xx_rwtm_rx_msg reply; |
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void *buf; |
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dma_addr_t buf_phys; |
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struct mutex busy; |
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struct completion cmd_done; |
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/* board information */ |
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int has_board_info; |
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u64 serial_number; |
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int board_version, ram_size; |
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u8 mac_address1[6], mac_address2[6]; |
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/* public key burned in eFuse */ |
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int has_pubkey; |
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u8 pubkey[135]; |
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#ifdef CONFIG_DEBUG_FS |
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/* |
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* Signature process. This is currently done via debugfs, because it |
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* does not conform to the sysfs standard "one file per attribute". |
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* It should be rewritten via crypto API once akcipher API is available |
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* from userspace. |
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*/ |
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struct dentry *debugfs_root; |
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u32 last_sig[34]; |
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int last_sig_done; |
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#endif |
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}; |
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struct mox_kobject { |
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struct kobject kobj; |
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struct mox_rwtm *rwtm; |
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}; |
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static inline struct kobject *rwtm_to_kobj(struct mox_rwtm *rwtm) |
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{ |
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return &rwtm->kobj->kobj; |
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} |
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static inline struct mox_rwtm *to_rwtm(struct kobject *kobj) |
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{ |
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return container_of(kobj, struct mox_kobject, kobj)->rwtm; |
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} |
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static void mox_kobj_release(struct kobject *kobj) |
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{ |
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kfree(to_rwtm(kobj)->kobj); |
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} |
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static struct kobj_type mox_kobj_ktype = { |
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.release = mox_kobj_release, |
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.sysfs_ops = &kobj_sysfs_ops, |
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}; |
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static int mox_kobj_create(struct mox_rwtm *rwtm) |
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{ |
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rwtm->kobj = kzalloc(sizeof(*rwtm->kobj), GFP_KERNEL); |
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if (!rwtm->kobj) |
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return -ENOMEM; |
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kobject_init(rwtm_to_kobj(rwtm), &mox_kobj_ktype); |
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if (kobject_add(rwtm_to_kobj(rwtm), firmware_kobj, "turris-mox-rwtm")) { |
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kobject_put(rwtm_to_kobj(rwtm)); |
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return -ENXIO; |
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} |
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rwtm->kobj->rwtm = rwtm; |
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return 0; |
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} |
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#define MOX_ATTR_RO(name, format, cat) \ |
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static ssize_t \ |
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name##_show(struct kobject *kobj, struct kobj_attribute *a, \ |
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char *buf) \ |
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{ \ |
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struct mox_rwtm *rwtm = to_rwtm(kobj); \ |
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if (!rwtm->has_##cat) \ |
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return -ENODATA; \ |
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return sprintf(buf, format, rwtm->name); \ |
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} \ |
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static struct kobj_attribute mox_attr_##name = __ATTR_RO(name) |
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MOX_ATTR_RO(serial_number, "%016llX\n", board_info); |
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MOX_ATTR_RO(board_version, "%i\n", board_info); |
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MOX_ATTR_RO(ram_size, "%i\n", board_info); |
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MOX_ATTR_RO(mac_address1, "%pM\n", board_info); |
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MOX_ATTR_RO(mac_address2, "%pM\n", board_info); |
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MOX_ATTR_RO(pubkey, "%s\n", pubkey); |
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static int mox_get_status(enum mbox_cmd cmd, u32 retval) |
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{ |
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if (MBOX_STS_CMD(retval) != cmd || |
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MBOX_STS_ERROR(retval) != MBOX_STS_SUCCESS) |
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return -EIO; |
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else if (MBOX_STS_ERROR(retval) == MBOX_STS_FAIL) |
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return -(int)MBOX_STS_VALUE(retval); |
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else |
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return MBOX_STS_VALUE(retval); |
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} |
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static const struct attribute *mox_rwtm_attrs[] = { |
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&mox_attr_serial_number.attr, |
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&mox_attr_board_version.attr, |
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&mox_attr_ram_size.attr, |
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&mox_attr_mac_address1.attr, |
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&mox_attr_mac_address2.attr, |
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&mox_attr_pubkey.attr, |
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NULL |
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}; |
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static void mox_rwtm_rx_callback(struct mbox_client *cl, void *data) |
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{ |
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struct mox_rwtm *rwtm = dev_get_drvdata(cl->dev); |
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struct armada_37xx_rwtm_rx_msg *msg = data; |
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rwtm->reply = *msg; |
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complete(&rwtm->cmd_done); |
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} |
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static void reply_to_mac_addr(u8 *mac, u32 t1, u32 t2) |
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{ |
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mac[0] = t1 >> 8; |
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mac[1] = t1; |
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mac[2] = t2 >> 24; |
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mac[3] = t2 >> 16; |
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mac[4] = t2 >> 8; |
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mac[5] = t2; |
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} |
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static int mox_get_board_info(struct mox_rwtm *rwtm) |
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{ |
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struct armada_37xx_rwtm_tx_msg msg; |
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struct armada_37xx_rwtm_rx_msg *reply = &rwtm->reply; |
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int ret; |
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msg.command = MBOX_CMD_BOARD_INFO; |
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ret = mbox_send_message(rwtm->mbox, &msg); |
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if (ret < 0) |
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return ret; |
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ret = wait_for_completion_timeout(&rwtm->cmd_done, HZ / 2); |
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if (ret < 0) |
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return ret; |
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ret = mox_get_status(MBOX_CMD_BOARD_INFO, reply->retval); |
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if (ret < 0 && ret != -ENODATA) { |
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return ret; |
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} else if (ret == -ENODATA) { |
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dev_warn(rwtm->dev, |
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"Board does not have manufacturing information burned!\n"); |
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} else { |
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rwtm->serial_number = reply->status[1]; |
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rwtm->serial_number <<= 32; |
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rwtm->serial_number |= reply->status[0]; |
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rwtm->board_version = reply->status[2]; |
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rwtm->ram_size = reply->status[3]; |
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reply_to_mac_addr(rwtm->mac_address1, reply->status[4], |
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reply->status[5]); |
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reply_to_mac_addr(rwtm->mac_address2, reply->status[6], |
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reply->status[7]); |
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rwtm->has_board_info = 1; |
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pr_info("Turris Mox serial number %016llX\n", |
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rwtm->serial_number); |
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pr_info(" board version %i\n", rwtm->board_version); |
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pr_info(" burned RAM size %i MiB\n", rwtm->ram_size); |
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} |
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msg.command = MBOX_CMD_ECDSA_PUB_KEY; |
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ret = mbox_send_message(rwtm->mbox, &msg); |
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if (ret < 0) |
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return ret; |
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ret = wait_for_completion_timeout(&rwtm->cmd_done, HZ / 2); |
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if (ret < 0) |
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return ret; |
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ret = mox_get_status(MBOX_CMD_ECDSA_PUB_KEY, reply->retval); |
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if (ret < 0 && ret != -ENODATA) { |
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return ret; |
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} else if (ret == -ENODATA) { |
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dev_warn(rwtm->dev, "Board has no public key burned!\n"); |
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} else { |
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u32 *s = reply->status; |
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rwtm->has_pubkey = 1; |
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sprintf(rwtm->pubkey, |
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"%06x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x", |
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ret, s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7], |
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s[8], s[9], s[10], s[11], s[12], s[13], s[14], s[15]); |
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} |
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return 0; |
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} |
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static int mox_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait) |
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{ |
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struct mox_rwtm *rwtm = (struct mox_rwtm *) rng->priv; |
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struct armada_37xx_rwtm_tx_msg msg; |
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int ret; |
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if (max > 4096) |
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max = 4096; |
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msg.command = MBOX_CMD_GET_RANDOM; |
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msg.args[0] = 1; |
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msg.args[1] = rwtm->buf_phys; |
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msg.args[2] = (max + 3) & ~3; |
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if (!wait) { |
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if (!mutex_trylock(&rwtm->busy)) |
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return -EBUSY; |
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} else { |
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mutex_lock(&rwtm->busy); |
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} |
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ret = mbox_send_message(rwtm->mbox, &msg); |
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if (ret < 0) |
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goto unlock_mutex; |
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ret = wait_for_completion_interruptible(&rwtm->cmd_done); |
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if (ret < 0) |
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goto unlock_mutex; |
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ret = mox_get_status(MBOX_CMD_GET_RANDOM, rwtm->reply.retval); |
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if (ret < 0) |
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goto unlock_mutex; |
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memcpy(data, rwtm->buf, max); |
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ret = max; |
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unlock_mutex: |
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mutex_unlock(&rwtm->busy); |
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return ret; |
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} |
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#ifdef CONFIG_DEBUG_FS |
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static int rwtm_debug_open(struct inode *inode, struct file *file) |
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{ |
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file->private_data = inode->i_private; |
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return nonseekable_open(inode, file); |
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} |
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static ssize_t do_sign_read(struct file *file, char __user *buf, size_t len, |
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loff_t *ppos) |
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{ |
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struct mox_rwtm *rwtm = file->private_data; |
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ssize_t ret; |
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/* only allow one read, of 136 bytes, from position 0 */ |
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if (*ppos != 0) |
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return 0; |
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if (len < 136) |
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return -EINVAL; |
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if (!rwtm->last_sig_done) |
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return -ENODATA; |
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/* 2 arrays of 17 32-bit words are 136 bytes */ |
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ret = simple_read_from_buffer(buf, len, ppos, rwtm->last_sig, 136); |
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rwtm->last_sig_done = 0; |
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return ret; |
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} |
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static ssize_t do_sign_write(struct file *file, const char __user *buf, |
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size_t len, loff_t *ppos) |
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{ |
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struct mox_rwtm *rwtm = file->private_data; |
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struct armada_37xx_rwtm_rx_msg *reply = &rwtm->reply; |
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struct armada_37xx_rwtm_tx_msg msg; |
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loff_t dummy = 0; |
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ssize_t ret; |
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/* the input is a SHA-512 hash, so exactly 64 bytes have to be read */ |
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if (len != 64) |
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return -EINVAL; |
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/* if last result is not zero user has not read that information yet */ |
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if (rwtm->last_sig_done) |
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return -EBUSY; |
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if (!mutex_trylock(&rwtm->busy)) |
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return -EBUSY; |
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/* |
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* Here we have to send: |
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* 1. Address of the input to sign. |
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* The input is an array of 17 32-bit words, the first (most |
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* significat) is 0, the rest 16 words are copied from the SHA-512 |
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* hash given by the user and converted from BE to LE. |
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* 2. Address of the buffer where ECDSA signature value R shall be |
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* stored by the rWTM firmware. |
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* 3. Address of the buffer where ECDSA signature value S shall be |
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* stored by the rWTM firmware. |
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*/ |
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memset(rwtm->buf, 0, 4); |
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ret = simple_write_to_buffer(rwtm->buf + 4, 64, &dummy, buf, len); |
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if (ret < 0) |
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goto unlock_mutex; |
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be32_to_cpu_array(rwtm->buf, rwtm->buf, 17); |
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msg.command = MBOX_CMD_SIGN; |
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msg.args[0] = 1; |
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msg.args[1] = rwtm->buf_phys; |
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msg.args[2] = rwtm->buf_phys + 68; |
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msg.args[3] = rwtm->buf_phys + 2 * 68; |
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ret = mbox_send_message(rwtm->mbox, &msg); |
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if (ret < 0) |
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goto unlock_mutex; |
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ret = wait_for_completion_interruptible(&rwtm->cmd_done); |
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if (ret < 0) |
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goto unlock_mutex; |
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ret = MBOX_STS_VALUE(reply->retval); |
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if (MBOX_STS_ERROR(reply->retval) != MBOX_STS_SUCCESS) |
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goto unlock_mutex; |
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/* |
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* Here we read the R and S values of the ECDSA signature |
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* computed by the rWTM firmware and convert their words from |
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* LE to BE. |
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*/ |
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memcpy(rwtm->last_sig, rwtm->buf + 68, 136); |
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cpu_to_be32_array(rwtm->last_sig, rwtm->last_sig, 34); |
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rwtm->last_sig_done = 1; |
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mutex_unlock(&rwtm->busy); |
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return len; |
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unlock_mutex: |
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mutex_unlock(&rwtm->busy); |
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return ret; |
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} |
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static const struct file_operations do_sign_fops = { |
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.owner = THIS_MODULE, |
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.open = rwtm_debug_open, |
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.read = do_sign_read, |
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.write = do_sign_write, |
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.llseek = no_llseek, |
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}; |
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static int rwtm_register_debugfs(struct mox_rwtm *rwtm) |
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{ |
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struct dentry *root, *entry; |
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root = debugfs_create_dir("turris-mox-rwtm", NULL); |
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if (IS_ERR(root)) |
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return PTR_ERR(root); |
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entry = debugfs_create_file_unsafe("do_sign", 0600, root, rwtm, |
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&do_sign_fops); |
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if (IS_ERR(entry)) |
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goto err_remove; |
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rwtm->debugfs_root = root; |
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return 0; |
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err_remove: |
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debugfs_remove_recursive(root); |
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return PTR_ERR(entry); |
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} |
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static void rwtm_unregister_debugfs(struct mox_rwtm *rwtm) |
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{ |
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debugfs_remove_recursive(rwtm->debugfs_root); |
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} |
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#else |
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static inline int rwtm_register_debugfs(struct mox_rwtm *rwtm) |
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{ |
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return 0; |
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} |
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static inline void rwtm_unregister_debugfs(struct mox_rwtm *rwtm) |
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{ |
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} |
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#endif |
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static int turris_mox_rwtm_probe(struct platform_device *pdev) |
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{ |
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struct mox_rwtm *rwtm; |
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struct device *dev = &pdev->dev; |
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int ret; |
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rwtm = devm_kzalloc(dev, sizeof(*rwtm), GFP_KERNEL); |
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if (!rwtm) |
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return -ENOMEM; |
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rwtm->dev = dev; |
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rwtm->buf = dmam_alloc_coherent(dev, PAGE_SIZE, &rwtm->buf_phys, |
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GFP_KERNEL); |
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if (!rwtm->buf) |
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return -ENOMEM; |
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ret = mox_kobj_create(rwtm); |
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if (ret < 0) { |
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dev_err(dev, "Cannot create turris-mox-rwtm kobject!\n"); |
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return ret; |
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} |
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ret = sysfs_create_files(rwtm_to_kobj(rwtm), mox_rwtm_attrs); |
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if (ret < 0) { |
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dev_err(dev, "Cannot create sysfs files!\n"); |
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goto put_kobj; |
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} |
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platform_set_drvdata(pdev, rwtm); |
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mutex_init(&rwtm->busy); |
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rwtm->mbox_client.dev = dev; |
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rwtm->mbox_client.rx_callback = mox_rwtm_rx_callback; |
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rwtm->mbox = mbox_request_channel(&rwtm->mbox_client, 0); |
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if (IS_ERR(rwtm->mbox)) { |
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ret = PTR_ERR(rwtm->mbox); |
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if (ret != -EPROBE_DEFER) |
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dev_err(dev, "Cannot request mailbox channel: %i\n", |
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ret); |
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goto remove_files; |
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} |
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init_completion(&rwtm->cmd_done); |
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ret = mox_get_board_info(rwtm); |
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if (ret < 0) |
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dev_warn(dev, "Cannot read board information: %i\n", ret); |
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rwtm->hwrng.name = DRIVER_NAME "_hwrng"; |
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rwtm->hwrng.read = mox_hwrng_read; |
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rwtm->hwrng.priv = (unsigned long) rwtm; |
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rwtm->hwrng.quality = 1024; |
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ret = devm_hwrng_register(dev, &rwtm->hwrng); |
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if (ret < 0) { |
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dev_err(dev, "Cannot register HWRNG: %i\n", ret); |
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goto free_channel; |
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} |
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ret = rwtm_register_debugfs(rwtm); |
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if (ret < 0) { |
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dev_err(dev, "Failed creating debugfs entries: %i\n", ret); |
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goto free_channel; |
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} |
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return 0; |
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free_channel: |
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mbox_free_channel(rwtm->mbox); |
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remove_files: |
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sysfs_remove_files(rwtm_to_kobj(rwtm), mox_rwtm_attrs); |
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put_kobj: |
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kobject_put(rwtm_to_kobj(rwtm)); |
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return ret; |
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} |
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static int turris_mox_rwtm_remove(struct platform_device *pdev) |
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{ |
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struct mox_rwtm *rwtm = platform_get_drvdata(pdev); |
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rwtm_unregister_debugfs(rwtm); |
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sysfs_remove_files(rwtm_to_kobj(rwtm), mox_rwtm_attrs); |
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kobject_put(rwtm_to_kobj(rwtm)); |
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mbox_free_channel(rwtm->mbox); |
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return 0; |
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} |
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static const struct of_device_id turris_mox_rwtm_match[] = { |
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{ .compatible = "cznic,turris-mox-rwtm", }, |
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{ }, |
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}; |
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MODULE_DEVICE_TABLE(of, turris_mox_rwtm_match); |
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|
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static struct platform_driver turris_mox_rwtm_driver = { |
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.probe = turris_mox_rwtm_probe, |
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.remove = turris_mox_rwtm_remove, |
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.driver = { |
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.name = DRIVER_NAME, |
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.of_match_table = turris_mox_rwtm_match, |
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}, |
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}; |
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module_platform_driver(turris_mox_rwtm_driver); |
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|
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MODULE_LICENSE("GPL v2"); |
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MODULE_DESCRIPTION("Turris Mox rWTM firmware driver"); |
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MODULE_AUTHOR("Marek Behun <[email protected]>");
|
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|