Quelle  gb-beagleplay.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Beagleplay Linux Driver for Greybus
 *
 * Copyright (c) 2023 Ayush Singh <ayushdevel1325@gmail.com>
 * Copyright (c) 2023 BeagleBoard.org Foundation
 */

#include <linux/unaligned.h>
#include <linux/crc32.h>
#include <linux/gpio/consumer.h>
#include <linux/firmware.h>
#include <linux/greybus.h>
#include <linux/serdev.h>
#include <linux/crc-ccitt.h>
#include <linux/circ_buf.h>

#define CC1352_FIRMWARE_SIZE (704 * 1024)
#define CC1352_BOOTLOADER_TIMEOUT 2000
#define CC1352_BOOTLOADER_ACK 0xcc
#define CC1352_BOOTLOADER_NACK 0x33

#define RX_HDLC_PAYLOAD 256
#define CRC_LEN 2
#define MAX_RX_HDLC (1 + RX_HDLC_PAYLOAD + CRC_LEN)
#define TX_CIRC_BUF_SIZE 1024

#define ADDRESS_GREYBUS 0x01
#define ADDRESS_DBG 0x02
#define ADDRESS_CONTROL 0x03

#define HDLC_FRAME 0x7E
#define HDLC_ESC 0x7D
#define HDLC_XOR 0x20

#define CONTROL_SVC_START 0x01
#define CONTROL_SVC_STOP 0x02

/* The maximum number of CPorts supported by Greybus Host Device */
#define GB_MAX_CPORTS 32

/**
 * struct gb_beagleplay - BeaglePlay Greybus driver
 *
 * @sd: underlying serdev device
 *
 * @gb_hd: greybus host device
 *
 * @tx_work: hdlc transmit work
 * @tx_producer_lock: hdlc transmit data producer lock. acquired when appending data to buffer.
 * @tx_consumer_lock: hdlc transmit data consumer lock. acquired when sending data over uart.
 * @tx_circ_buf: hdlc transmit circular buffer.
 * @tx_crc: hdlc transmit crc-ccitt fcs
 *
 * @rx_buffer_len: length of receive buffer filled.
 * @rx_buffer: hdlc frame receive buffer
 * @rx_in_esc: hdlc rx flag to indicate ESC frame
 *
 * @fwl: underlying firmware upload device
 * @bootloader_backdoor_gpio: cc1352p7 boot gpio
 * @rst_gpio: cc1352p7 reset gpio
 * @flashing_mode: flag to indicate that flashing is currently in progress
 * @fwl_ack_com: completion to signal an Ack/Nack
 * @fwl_ack: Ack/Nack byte received
 * @fwl_cmd_response_com: completion to signal a bootloader command response
 * @fwl_cmd_response: bootloader command response data
 * @fwl_crc32: crc32 of firmware to flash
 * @fwl_reset_addr: flag to indicate if we need to send COMMAND_DOWNLOAD again
 */
struct gb_beagleplay {
 struct serdev_device *sd;

 struct gb_host_device *gb_hd;

 struct work_struct tx_work;
 spinlock_t tx_producer_lock;
 spinlock_t tx_consumer_lock;
 struct circ_buf tx_circ_buf;
 u16 tx_crc;

 u16 rx_buffer_len;
 bool rx_in_esc;
 u8 rx_buffer[MAX_RX_HDLC];

 struct fw_upload *fwl;
 struct gpio_desc *bootloader_backdoor_gpio;
 struct gpio_desc *rst_gpio;
 bool flashing_mode;
 struct completion fwl_ack_com;
 u8 fwl_ack;
 struct completion fwl_cmd_response_com;
 u32 fwl_cmd_response;
 u32 fwl_crc32;
 bool fwl_reset_addr;
};

/**
 * struct hdlc_payload - Structure to represent part of HDCL frame payload data.
 *
 * @len: buffer length in bytes
 * @buf: payload buffer
 */
struct hdlc_payload {
 u16 len;
 void *buf;
};

/**
 * struct hdlc_greybus_frame - Structure to represent greybus HDLC frame payload
 *
 * @cport: cport id
 * @hdr: greybus operation header
 * @payload: greybus message payload
 *
 * The HDLC payload sent over UART for greybus address has cport preappended to greybus message
 */
struct hdlc_greybus_frame {
 __le16 cport;
 struct gb_operation_msg_hdr hdr;
 u8 payload[];
} __packed;

/**
 * enum cc1352_bootloader_cmd: CC1352 Bootloader Commands
 *
 * @COMMAND_DOWNLOAD: Prepares flash programming
 * @COMMAND_GET_STATUS: Returns the status of the last command that was  issued
 * @COMMAND_SEND_DATA: Transfers data and programs flash
 * @COMMAND_RESET: Performs a system reset
 * @COMMAND_CRC32: Calculates CRC32 over a specified memory area
 * @COMMAND_BANK_ERASE: Performs an erase of all of the customer-accessible
 *                      flash sectors not protected by FCFG1 and CCFG
 *                      writeprotect bits.
 *
 * CC1352 Bootloader serial bus commands
 */
enum cc1352_bootloader_cmd {
 COMMAND_DOWNLOAD = 0x21,
 COMMAND_GET_STATUS = 0x23,
 COMMAND_SEND_DATA = 0x24,
 COMMAND_RESET = 0x25,
 COMMAND_CRC32 = 0x27,
 COMMAND_BANK_ERASE = 0x2c,
};

/**
 * enum cc1352_bootloader_status: CC1352 Bootloader COMMAND_GET_STATUS response
 *
 * @COMMAND_RET_SUCCESS: Status for successful command
 * @COMMAND_RET_UNKNOWN_CMD: Status for unknown command
 * @COMMAND_RET_INVALID_CMD: Status for invalid command (in other words,
 *                           incorrect packet size)
 * @COMMAND_RET_INVALID_ADR: Status for invalid input address
 * @COMMAND_RET_FLASH_FAIL: Status for failing flash erase or program operation
 */
enum cc1352_bootloader_status {
 COMMAND_RET_SUCCESS = 0x40,
 COMMAND_RET_UNKNOWN_CMD = 0x41,
 COMMAND_RET_INVALID_CMD = 0x42,
 COMMAND_RET_INVALID_ADR = 0x43,
 COMMAND_RET_FLASH_FAIL = 0x44,
};

/**
 * struct cc1352_bootloader_packet: CC1352 Bootloader Request Packet
 *
 * @len: length of packet + optional request data
 * @checksum: 8-bit checksum excluding len
 * @cmd: bootloader command
 */
struct cc1352_bootloader_packet {
 u8 len;
 u8 checksum;
 u8 cmd;
} __packed;

#define CC1352_BOOTLOADER_PKT_MAX_SIZE \
 (U8_MAX - sizeof(struct cc1352_bootloader_packet))

/**
 * struct cc1352_bootloader_download_cmd_data: CC1352 Bootloader COMMAND_DOWNLOAD request data
 *
 * @addr: address to start programming data into
 * @size: size of data that will be sent
 */
struct cc1352_bootloader_download_cmd_data {
 __be32 addr;
 __be32 size;
} __packed;

/**
 * struct cc1352_bootloader_crc32_cmd_data: CC1352 Bootloader COMMAND_CRC32 request data
 *
 * @addr: address where crc32 calculation starts
 * @size: number of bytes comprised by crc32 calculation
 * @read_repeat: number of read repeats for each data location
 */
struct cc1352_bootloader_crc32_cmd_data {
 __be32 addr;
 __be32 size;
 __be32 read_repeat;
} __packed;

static void hdlc_rx_greybus_frame(struct gb_beagleplay *bg, u8 *buf, u16 len)
{
 struct hdlc_greybus_frame *gb_frame = (struct hdlc_greybus_frame *)buf;
 u16 cport_id = le16_to_cpu(gb_frame->cport);
 u16 gb_msg_len = le16_to_cpu(gb_frame->hdr.size);

 dev_dbg(&bg->sd->dev, "Greybus Operation %u type %X cport %u status %u received",
  gb_frame->hdr.operation_id, gb_frame->hdr.type, cport_id, gb_frame->hdr.result);

 greybus_data_rcvd(bg->gb_hd, cport_id, (u8 *)&gb_frame->hdr, gb_msg_len);
}

static void hdlc_rx_dbg_frame(const struct gb_beagleplay *bg, const char *buf, u16 len)
{
 dev_dbg(&bg->sd->dev, "CC1352 Log: %.*s", (int)len, buf);
}

/**
 * hdlc_write() - Consume HDLC Buffer.
 * @bg: beagleplay greybus driver
 *
 * Assumes that consumer lock has been acquired.
 */
static void hdlc_write(struct gb_beagleplay *bg)
{
 int written;
 /* Start consuming HDLC data */
 int head = smp_load_acquire(&bg->tx_circ_buf.head);
 int tail = bg->tx_circ_buf.tail;
 int count = CIRC_CNT_TO_END(head, tail, TX_CIRC_BUF_SIZE);
 const unsigned char *buf = &bg->tx_circ_buf.buf[tail];

 if (count > 0) {
  written = serdev_device_write_buf(bg->sd, buf, count);

  /* Finish consuming HDLC data */
  smp_store_release(&bg->tx_circ_buf.tail, (tail + written) & (TX_CIRC_BUF_SIZE - 1));
 }
}

/**
 * hdlc_append() - Queue HDLC data for sending.
 * @bg: beagleplay greybus driver
 * @value: hdlc byte to transmit
 *
 * Assumes that producer lock as been acquired.
 */
static void hdlc_append(struct gb_beagleplay *bg, u8 value)
{
 int tail, head = bg->tx_circ_buf.head;

 while (true) {
  tail = READ_ONCE(bg->tx_circ_buf.tail);

  if (CIRC_SPACE(head, tail, TX_CIRC_BUF_SIZE) >= 1) {
   bg->tx_circ_buf.buf[head] = value;

   /* Finish producing HDLC byte */
   smp_store_release(&bg->tx_circ_buf.head,
       (head + 1) & (TX_CIRC_BUF_SIZE - 1));
   return;
  }
  dev_warn(&bg->sd->dev, "Tx circ buf full");
  usleep_range(3000, 5000);
 }
}

static void hdlc_append_escaped(struct gb_beagleplay *bg, u8 value)
{
 if (value == HDLC_FRAME || value == HDLC_ESC) {
  hdlc_append(bg, HDLC_ESC);
  value ^= HDLC_XOR;
 }
 hdlc_append(bg, value);
}

static void hdlc_append_tx_frame(struct gb_beagleplay *bg)
{
 bg->tx_crc = 0xFFFF;
 hdlc_append(bg, HDLC_FRAME);
}

static void hdlc_append_tx_u8(struct gb_beagleplay *bg, u8 value)
{
 bg->tx_crc = crc_ccitt(bg->tx_crc, &value, 1);
 hdlc_append_escaped(bg, value);
}

static void hdlc_append_tx_buf(struct gb_beagleplay *bg, const u8 *buf, u16 len)
{
 size_t i;

 for (i = 0; i < len; i++)
  hdlc_append_tx_u8(bg, buf[i]);
}

static void hdlc_append_tx_crc(struct gb_beagleplay *bg)
{
 bg->tx_crc ^= 0xffff;
 hdlc_append_escaped(bg, bg->tx_crc & 0xff);
 hdlc_append_escaped(bg, (bg->tx_crc >> 8) & 0xff);
}

static void hdlc_transmit(struct work_struct *work)
{
 struct gb_beagleplay *bg = container_of(work, struct gb_beagleplay, tx_work);

 spin_lock_bh(&bg->tx_consumer_lock);
 hdlc_write(bg);
 spin_unlock_bh(&bg->tx_consumer_lock);
}

static void hdlc_tx_frames(struct gb_beagleplay *bg, u8 address, u8 control,
      const struct hdlc_payload payloads[], size_t count)
{
 size_t i;

 spin_lock(&bg->tx_producer_lock);

 hdlc_append_tx_frame(bg);
 hdlc_append_tx_u8(bg, address);
 hdlc_append_tx_u8(bg, control);

 for (i = 0; i < count; ++i)
  hdlc_append_tx_buf(bg, payloads[i].buf, payloads[i].len);

 hdlc_append_tx_crc(bg);
 hdlc_append_tx_frame(bg);

 spin_unlock(&bg->tx_producer_lock);

 schedule_work(&bg->tx_work);
}

static void hdlc_tx_s_frame_ack(struct gb_beagleplay *bg)
{
 hdlc_tx_frames(bg, bg->rx_buffer[0], (bg->rx_buffer[1] >> 1) & 0x7, NULL, 0);
}

static void hdlc_rx_frame(struct gb_beagleplay *bg)
{
 u16 crc, len;
 u8 ctrl, *buf;
 u8 address = bg->rx_buffer[0];

 crc = crc_ccitt(0xffff, bg->rx_buffer, bg->rx_buffer_len);
 if (crc != 0xf0b8) {
  dev_warn_ratelimited(&bg->sd->dev, "CRC failed from %02x: 0x%04x", address, crc);
  return;
 }

 ctrl = bg->rx_buffer[1];
 buf = &bg->rx_buffer[2];
 len = bg->rx_buffer_len - 4;

 /* I-Frame, send S-Frame ACK */
 if ((ctrl & 1) == 0)
  hdlc_tx_s_frame_ack(bg);

 switch (address) {
 case ADDRESS_DBG:
  hdlc_rx_dbg_frame(bg, buf, len);
  break;
 case ADDRESS_GREYBUS:
  hdlc_rx_greybus_frame(bg, buf, len);
  break;
 default:
  dev_warn_ratelimited(&bg->sd->dev, "unknown frame %u", address);
 }
}

static size_t hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count)
{
 size_t i;
 u8 c;

 for (i = 0; i < count; ++i) {
  c = data[i];

  switch (c) {
  case HDLC_FRAME:
   if (bg->rx_buffer_len)
    hdlc_rx_frame(bg);

   bg->rx_buffer_len = 0;
   break;
  case HDLC_ESC:
   bg->rx_in_esc = true;
   break;
  default:
   if (bg->rx_in_esc) {
    c ^= 0x20;
    bg->rx_in_esc = false;
   }

   if (bg->rx_buffer_len < MAX_RX_HDLC) {
    bg->rx_buffer[bg->rx_buffer_len] = c;
    bg->rx_buffer_len++;
   } else {
    dev_err_ratelimited(&bg->sd->dev, "RX Buffer Overflow");
    bg->rx_buffer_len = 0;
   }
  }
 }

 return count;
}

static int hdlc_init(struct gb_beagleplay *bg)
{
 INIT_WORK(&bg->tx_work, hdlc_transmit);
 spin_lock_init(&bg->tx_producer_lock);
 spin_lock_init(&bg->tx_consumer_lock);
 bg->tx_circ_buf.head = 0;
 bg->tx_circ_buf.tail = 0;

 bg->tx_circ_buf.buf = devm_kmalloc(&bg->sd->dev, TX_CIRC_BUF_SIZE, GFP_KERNEL);
 if (!bg->tx_circ_buf.buf)
  return -ENOMEM;

 bg->rx_buffer_len = 0;
 bg->rx_in_esc = false;

 return 0;
}

static void hdlc_deinit(struct gb_beagleplay *bg)
{
 flush_work(&bg->tx_work);
}

/**
 * csum8: Calculate 8-bit checksum on data
 *
 * @data: bytes to calculate 8-bit checksum of
 * @size: number of bytes
 * @base: starting value for checksum
 */
static u8 csum8(const u8 *data, size_t size, u8 base)
{
 size_t i;
 u8 sum = base;

 for (i = 0; i < size; ++i)
  sum += data[i];

 return sum;
}

static void cc1352_bootloader_send_ack(struct gb_beagleplay *bg)
{
 static const u8 ack[] = { 0x00, CC1352_BOOTLOADER_ACK };

 serdev_device_write_buf(bg->sd, ack, sizeof(ack));
}

static void cc1352_bootloader_send_nack(struct gb_beagleplay *bg)
{
 static const u8 nack[] = { 0x00, CC1352_BOOTLOADER_NACK };

 serdev_device_write_buf(bg->sd, nack, sizeof(nack));
}

/**
 * cc1352_bootloader_pkt_rx: Process a CC1352 Bootloader Packet
 *
 * @bg: beagleplay greybus driver
 * @data: packet buffer
 * @count: packet buffer size
 *
 * @return: number of bytes processed
 *
 * Here are the steps to successfully receive a packet from cc1352 bootloader
 * according to the docs:
 * 1. Wait for nonzero data to be returned from the device. This is important
 *    as the device may send zero bytes between a sent and a received data
 *    packet. The first nonzero byte received is the size of the packet that is
 *    being received.
 * 2. Read the next byte, which is the checksum for the packet.
 * 3. Read the data bytes from the device. During the data phase, packet size
 *    minus 2 bytes is sent.
 * 4. Calculate the checksum of the data bytes and verify it matches the
 *    checksum received in the packet.
 * 5. Send an acknowledge byte or a not-acknowledge byte to the device to
 *    indicate the successful or unsuccessful reception of the packet.
 */
static int cc1352_bootloader_pkt_rx(struct gb_beagleplay *bg, const u8 *data,
        size_t count)
{
 bool is_valid = false;

 switch (data[0]) {
 /* Skip 0x00 bytes.  */
 case 0x00:
  return 1;
 case CC1352_BOOTLOADER_ACK:
 case CC1352_BOOTLOADER_NACK:
  WRITE_ONCE(bg->fwl_ack, data[0]);
  complete(&bg->fwl_ack_com);
  return 1;
 case 3:
  if (count < 3)
   return 0;
  is_valid = data[1] == data[2];
  WRITE_ONCE(bg->fwl_cmd_response, (u32)data[2]);
  break;
 case 6:
  if (count < 6)
   return 0;
  is_valid = csum8(&data[2], sizeof(__be32), 0) == data[1];
  WRITE_ONCE(bg->fwl_cmd_response, get_unaligned_be32(&data[2]));
  break;
 default:
  return -EINVAL;
 }

 if (is_valid) {
  cc1352_bootloader_send_ack(bg);
  complete(&bg->fwl_cmd_response_com);
 } else {
  dev_warn(&bg->sd->dev,
    "Dropping bootloader packet with invalid checksum");
  cc1352_bootloader_send_nack(bg);
 }

 return data[0];
}

static size_t cc1352_bootloader_rx(struct gb_beagleplay *bg, const u8 *data,
       size_t count)
{
 int ret;
 size_t off = 0;

 memcpy(bg->rx_buffer + bg->rx_buffer_len, data, count);
 bg->rx_buffer_len += count;

 do {
  ret = cc1352_bootloader_pkt_rx(bg, bg->rx_buffer + off,
            bg->rx_buffer_len - off);
  if (ret < 0)
   return dev_err_probe(&bg->sd->dev, ret,
          "Invalid Packet");
  off += ret;
 } while (ret > 0 && off < count);

 bg->rx_buffer_len -= off;
 memmove(bg->rx_buffer, bg->rx_buffer + off, bg->rx_buffer_len);

 return count;
}

static size_t gb_tty_receive(struct serdev_device *sd, const u8 *data,
        size_t count)
{
 struct gb_beagleplay *bg = serdev_device_get_drvdata(sd);

 if (READ_ONCE(bg->flashing_mode))
  return cc1352_bootloader_rx(bg, data, count);

 return hdlc_rx(bg, data, count);
}

static void gb_tty_wakeup(struct serdev_device *serdev)
{
 struct gb_beagleplay *bg = serdev_device_get_drvdata(serdev);

 if (!READ_ONCE(bg->flashing_mode))
  schedule_work(&bg->tx_work);
}

static struct serdev_device_ops gb_beagleplay_ops = {
 .receive_buf = gb_tty_receive,
 .write_wakeup = gb_tty_wakeup,
};

/**
 * gb_message_send() - Send greybus message using HDLC over UART
 *
 * @hd: pointer to greybus host device
 * @cport: AP cport where message originates
 * @msg: greybus message to send
 * @mask: gfp mask
 *
 * Greybus HDLC frame has the following payload:
 * 1. le16 cport
 * 2. gb_operation_msg_hdr msg_header
 * 3. u8 *msg_payload
 */
static int gb_message_send(struct gb_host_device *hd, u16 cport, struct gb_message *msg, gfp_t mask)
{
 struct gb_beagleplay *bg = dev_get_drvdata(&hd->dev);
 struct hdlc_payload payloads[3];
 __le16 cport_id = cpu_to_le16(cport);

 dev_dbg(&hd->dev, "Sending greybus message with Operation %u, Type: %X on Cport %u",
  msg->header->operation_id, msg->header->type, cport);

 if (le16_to_cpu(msg->header->size) > RX_HDLC_PAYLOAD)
  return dev_err_probe(&hd->dev, -E2BIG, "Greybus message too big");

 payloads[0].buf = &cport_id;
 payloads[0].len = sizeof(cport_id);
 payloads[1].buf = msg->header;
 payloads[1].len = sizeof(*msg->header);
 payloads[2].buf = msg->payload;
 payloads[2].len = msg->payload_size;

 hdlc_tx_frames(bg, ADDRESS_GREYBUS, 0x03, payloads, 3);
 greybus_message_sent(bg->gb_hd, msg, 0);

 return 0;
}

static void gb_message_cancel(struct gb_message *message)
{
}

static struct gb_hd_driver gb_hdlc_driver = { .message_send = gb_message_send,
           .message_cancel = gb_message_cancel };

static void gb_beagleplay_start_svc(struct gb_beagleplay *bg)
{
 const u8 command = CONTROL_SVC_START;
 const struct hdlc_payload payload = { .len = 1, .buf = (void *)&command };

 hdlc_tx_frames(bg, ADDRESS_CONTROL, 0x03, &payload, 1);
}

static void gb_beagleplay_stop_svc(struct gb_beagleplay *bg)
{
 const u8 command = CONTROL_SVC_STOP;
 const struct hdlc_payload payload = { .len = 1, .buf = (void *)&command };

 hdlc_tx_frames(bg, ADDRESS_CONTROL, 0x03, &payload, 1);
}

static int cc1352_bootloader_wait_for_ack(struct gb_beagleplay *bg)
{
 int ret;

 ret = wait_for_completion_timeout(
  &bg->fwl_ack_com, msecs_to_jiffies(CC1352_BOOTLOADER_TIMEOUT));
 if (ret < 0)
  return dev_err_probe(&bg->sd->dev, ret,
         "Failed to acquire ack semaphore");

 switch (READ_ONCE(bg->fwl_ack)) {
 case CC1352_BOOTLOADER_ACK:
  return 0;
 case CC1352_BOOTLOADER_NACK:
  return -EAGAIN;
 default:
  return -EINVAL;
 }
}

static int cc1352_bootloader_sync(struct gb_beagleplay *bg)
{
 static const u8 sync_bytes[] = { 0x55, 0x55 };

 serdev_device_write_buf(bg->sd, sync_bytes, sizeof(sync_bytes));
 return cc1352_bootloader_wait_for_ack(bg);
}

static int cc1352_bootloader_get_status(struct gb_beagleplay *bg)
{
 int ret;
 static const struct cc1352_bootloader_packet pkt = {
  .len = sizeof(pkt),
  .checksum = COMMAND_GET_STATUS,
  .cmd = COMMAND_GET_STATUS
 };

 serdev_device_write_buf(bg->sd, (const u8 *)&pkt, sizeof(pkt));
 ret = cc1352_bootloader_wait_for_ack(bg);
 if (ret < 0)
  return ret;

 ret = wait_for_completion_timeout(
  &bg->fwl_cmd_response_com,
  msecs_to_jiffies(CC1352_BOOTLOADER_TIMEOUT));
 if (ret < 0)
  return dev_err_probe(&bg->sd->dev, ret,
         "Failed to acquire last status semaphore");

 switch (READ_ONCE(bg->fwl_cmd_response)) {
 case COMMAND_RET_SUCCESS:
  return 0;
 default:
  return -EINVAL;
 }

 return 0;
}

static int cc1352_bootloader_erase(struct gb_beagleplay *bg)
{
 int ret;
 static const struct cc1352_bootloader_packet pkt = {
  .len = sizeof(pkt),
  .checksum = COMMAND_BANK_ERASE,
  .cmd = COMMAND_BANK_ERASE
 };

 serdev_device_write_buf(bg->sd, (const u8 *)&pkt, sizeof(pkt));

 ret = cc1352_bootloader_wait_for_ack(bg);
 if (ret < 0)
  return ret;

 return cc1352_bootloader_get_status(bg);
}

static int cc1352_bootloader_reset(struct gb_beagleplay *bg)
{
 static const struct cc1352_bootloader_packet pkt = {
  .len = sizeof(pkt),
  .checksum = COMMAND_RESET,
  .cmd = COMMAND_RESET
 };

 serdev_device_write_buf(bg->sd, (const u8 *)&pkt, sizeof(pkt));

 return cc1352_bootloader_wait_for_ack(bg);
}

/**
 * cc1352_bootloader_empty_pkt: Calculate the number of empty bytes in the current packet
 *
 * @data: packet bytes array to check
 * @size: number of bytes in array
 */
static size_t cc1352_bootloader_empty_pkt(const u8 *data, size_t size)
{
 size_t i;

 for (i = 0; i < size && data[i] == 0xff; ++i)
  continue;

 return i;
}

static int cc1352_bootloader_crc32(struct gb_beagleplay *bg, u32 *crc32)
{
 int ret;
 static const struct cc1352_bootloader_crc32_cmd_data cmd_data = {
  .addr = 0, .size = cpu_to_be32(704 * 1024), .read_repeat = 0
 };
 const struct cc1352_bootloader_packet pkt = {
  .len = sizeof(pkt) + sizeof(cmd_data),
  .checksum = csum8((const void *)&cmd_data, sizeof(cmd_data),
      COMMAND_CRC32),
  .cmd = COMMAND_CRC32
 };

 serdev_device_write_buf(bg->sd, (const u8 *)&pkt, sizeof(pkt));
 serdev_device_write_buf(bg->sd, (const u8 *)&cmd_data,
    sizeof(cmd_data));

 ret = cc1352_bootloader_wait_for_ack(bg);
 if (ret < 0)
  return ret;

 ret = wait_for_completion_timeout(
  &bg->fwl_cmd_response_com,
  msecs_to_jiffies(CC1352_BOOTLOADER_TIMEOUT));
 if (ret < 0)
  return dev_err_probe(&bg->sd->dev, ret,
         "Failed to acquire last status semaphore");

 *crc32 = READ_ONCE(bg->fwl_cmd_response);

 return 0;
}

static int cc1352_bootloader_download(struct gb_beagleplay *bg, u32 size,
          u32 addr)
{
 int ret;
 const struct cc1352_bootloader_download_cmd_data cmd_data = {
  .addr = cpu_to_be32(addr),
  .size = cpu_to_be32(size),
 };
 const struct cc1352_bootloader_packet pkt = {
  .len = sizeof(pkt) + sizeof(cmd_data),
  .checksum = csum8((const void *)&cmd_data, sizeof(cmd_data),
      COMMAND_DOWNLOAD),
  .cmd = COMMAND_DOWNLOAD
 };

 serdev_device_write_buf(bg->sd, (const u8 *)&pkt, sizeof(pkt));
 serdev_device_write_buf(bg->sd, (const u8 *)&cmd_data,
    sizeof(cmd_data));

 ret = cc1352_bootloader_wait_for_ack(bg);
 if (ret < 0)
  return ret;

 return cc1352_bootloader_get_status(bg);
}

static int cc1352_bootloader_send_data(struct gb_beagleplay *bg, const u8 *data,
           size_t size)
{
 int ret, rem = min(size, CC1352_BOOTLOADER_PKT_MAX_SIZE);
 const struct cc1352_bootloader_packet pkt = {
  .len = sizeof(pkt) + rem,
  .checksum = csum8(data, rem, COMMAND_SEND_DATA),
  .cmd = COMMAND_SEND_DATA
 };

 serdev_device_write_buf(bg->sd, (const u8 *)&pkt, sizeof(pkt));
 serdev_device_write_buf(bg->sd, data, rem);

 ret = cc1352_bootloader_wait_for_ack(bg);
 if (ret < 0)
  return ret;

 ret = cc1352_bootloader_get_status(bg);
 if (ret < 0)
  return ret;

 return rem;
}

static void gb_greybus_deinit(struct gb_beagleplay *bg)
{
 gb_hd_del(bg->gb_hd);
 gb_hd_put(bg->gb_hd);
}

static int gb_greybus_init(struct gb_beagleplay *bg)
{
 int ret;

 bg->gb_hd = gb_hd_create(&gb_hdlc_driver, &bg->sd->dev, TX_CIRC_BUF_SIZE, GB_MAX_CPORTS);
 if (IS_ERR(bg->gb_hd)) {
  dev_err(&bg->sd->dev, "Failed to create greybus host device");
  return PTR_ERR(bg->gb_hd);
 }

 ret = gb_hd_add(bg->gb_hd);
 if (ret) {
  dev_err(&bg->sd->dev, "Failed to add greybus host device");
  goto free_gb_hd;
 }
 dev_set_drvdata(&bg->gb_hd->dev, bg);

 return 0;

free_gb_hd:
 gb_greybus_deinit(bg);
 return ret;
}

static enum fw_upload_err cc1352_prepare(struct fw_upload *fw_upload,
      const u8 *data, u32 size)
{
 int ret;
 u32 curr_crc32;
 struct gb_beagleplay *bg = fw_upload->dd_handle;

 dev_info(&bg->sd->dev, "CC1352 Start Flashing...");

 if (size != CC1352_FIRMWARE_SIZE)
  return FW_UPLOAD_ERR_INVALID_SIZE;

 /* Might involve network calls */
 gb_greybus_deinit(bg);
 msleep(5 * MSEC_PER_SEC);

 gb_beagleplay_stop_svc(bg);
 msleep(200);
 flush_work(&bg->tx_work);

 serdev_device_wait_until_sent(bg->sd, CC1352_BOOTLOADER_TIMEOUT);

 WRITE_ONCE(bg->flashing_mode, true);

 gpiod_direction_output(bg->bootloader_backdoor_gpio, 0);
 gpiod_direction_output(bg->rst_gpio, 0);
 msleep(200);

 gpiod_set_value(bg->rst_gpio, 1);
 msleep(200);

 gpiod_set_value(bg->bootloader_backdoor_gpio, 1);
 msleep(200);

 gpiod_direction_input(bg->bootloader_backdoor_gpio);
 gpiod_direction_input(bg->rst_gpio);

 ret = cc1352_bootloader_sync(bg);
 if (ret < 0)
  return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_HW_ERROR,
         "Failed to sync");

 ret = cc1352_bootloader_crc32(bg, &curr_crc32);
 if (ret < 0)
  return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_HW_ERROR,
         "Failed to fetch crc32");

 bg->fwl_crc32 = crc32(0xffffffff, data, size) ^ 0xffffffff;

 /* Check if attempting to reflash same firmware */
 if (bg->fwl_crc32 == curr_crc32) {
  dev_warn(&bg->sd->dev, "Skipping reflashing same image");
  cc1352_bootloader_reset(bg);
  WRITE_ONCE(bg->flashing_mode, false);
  msleep(200);
  if (gb_greybus_init(bg) < 0)
   return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_RW_ERROR,
          "Failed to initialize greybus");
  gb_beagleplay_start_svc(bg);
  return FW_UPLOAD_ERR_FW_INVALID;
 }

 ret = cc1352_bootloader_erase(bg);
 if (ret < 0)
  return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_HW_ERROR,
         "Failed to erase");

 bg->fwl_reset_addr = true;

 return FW_UPLOAD_ERR_NONE;
}

static void cc1352_cleanup(struct fw_upload *fw_upload)
{
 struct gb_beagleplay *bg = fw_upload->dd_handle;

 WRITE_ONCE(bg->flashing_mode, false);
}

static enum fw_upload_err cc1352_write(struct fw_upload *fw_upload,
           const u8 *data, u32 offset, u32 size,
           u32 *written)
{
 int ret;
 size_t empty_bytes;
 struct gb_beagleplay *bg = fw_upload->dd_handle;

 /* Skip 0xff packets. Significant performance improvement */
 empty_bytes = cc1352_bootloader_empty_pkt(data + offset, size);
 if (empty_bytes >= CC1352_BOOTLOADER_PKT_MAX_SIZE) {
  bg->fwl_reset_addr = true;
  *written = empty_bytes;
  return FW_UPLOAD_ERR_NONE;
 }

 if (bg->fwl_reset_addr) {
  ret = cc1352_bootloader_download(bg, size, offset);
  if (ret < 0)
   return dev_err_probe(&bg->sd->dev,
          FW_UPLOAD_ERR_HW_ERROR,
          "Failed to send download cmd");

  bg->fwl_reset_addr = false;
 }

 ret = cc1352_bootloader_send_data(bg, data + offset, size);
 if (ret < 0)
  return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_HW_ERROR,
         "Failed to flash firmware");
 *written = ret;

 return FW_UPLOAD_ERR_NONE;
}

static enum fw_upload_err cc1352_poll_complete(struct fw_upload *fw_upload)
{
 u32 curr_crc32;
 struct gb_beagleplay *bg = fw_upload->dd_handle;

 if (cc1352_bootloader_crc32(bg, &curr_crc32) < 0)
  return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_HW_ERROR,
         "Failed to fetch crc32");

 if (bg->fwl_crc32 != curr_crc32)
  return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_FW_INVALID,
         "Invalid CRC32");

 if (cc1352_bootloader_reset(bg) < 0)
  return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_HW_ERROR,
         "Failed to reset");

 dev_info(&bg->sd->dev, "CC1352 Flashing Successful");
 WRITE_ONCE(bg->flashing_mode, false);
 msleep(200);

 if (gb_greybus_init(bg) < 0)
  return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_RW_ERROR,
         "Failed to initialize greybus");

 gb_beagleplay_start_svc(bg);

 return FW_UPLOAD_ERR_NONE;
}

static void cc1352_cancel(struct fw_upload *fw_upload)
{
 struct gb_beagleplay *bg = fw_upload->dd_handle;

 dev_info(&bg->sd->dev, "CC1352 Bootloader Cancel");

 cc1352_bootloader_reset(bg);
}

static void gb_serdev_deinit(struct gb_beagleplay *bg)
{
 serdev_device_close(bg->sd);
}

static int gb_serdev_init(struct gb_beagleplay *bg)
{
 int ret;

 serdev_device_set_drvdata(bg->sd, bg);
 serdev_device_set_client_ops(bg->sd, &gb_beagleplay_ops);
 ret = serdev_device_open(bg->sd);
 if (ret)
  return dev_err_probe(&bg->sd->dev, ret, "Unable to open serial device");

 serdev_device_set_baudrate(bg->sd, 115200);
 serdev_device_set_flow_control(bg->sd, false);

 return 0;
}

static const struct fw_upload_ops cc1352_bootloader_ops = {
 .prepare = cc1352_prepare,
 .write = cc1352_write,
 .poll_complete = cc1352_poll_complete,
 .cancel = cc1352_cancel,
 .cleanup = cc1352_cleanup
};

/*
 * Must only be called from probe() as the devres resources allocated here
 * will only be released on driver detach.
 */
static int gb_fw_init(struct gb_beagleplay *bg)
{
 struct fw_upload *fwl;
 struct gpio_desc *desc;

 bg->fwl = NULL;
 bg->bootloader_backdoor_gpio = NULL;
 bg->rst_gpio = NULL;
 bg->flashing_mode = false;
 bg->fwl_cmd_response = 0;
 bg->fwl_ack = 0;
 init_completion(&bg->fwl_ack_com);
 init_completion(&bg->fwl_cmd_response_com);

 desc = devm_gpiod_get(&bg->sd->dev, "bootloader-backdoor", GPIOD_IN);
 if (IS_ERR(desc))
  return PTR_ERR(desc);
 bg->bootloader_backdoor_gpio = desc;

 desc = devm_gpiod_get(&bg->sd->dev, "reset", GPIOD_IN);
 if (IS_ERR(desc))
  return PTR_ERR(desc);
 bg->rst_gpio = desc;

 fwl = firmware_upload_register(THIS_MODULE, &bg->sd->dev, "cc1352p7",
           &cc1352_bootloader_ops, bg);
 if (IS_ERR(fwl))
  return PTR_ERR(fwl);
 bg->fwl = fwl;

 return 0;
}

static void gb_fw_deinit(struct gb_beagleplay *bg)
{
 firmware_upload_unregister(bg->fwl);
}

static int gb_beagleplay_probe(struct serdev_device *serdev)
{
 int ret = 0;
 struct gb_beagleplay *bg;

 bg = devm_kmalloc(&serdev->dev, sizeof(*bg), GFP_KERNEL);
 if (!bg)
  return -ENOMEM;

 bg->sd = serdev;
 ret = gb_serdev_init(bg);
 if (ret)
  return ret;

 ret = hdlc_init(bg);
 if (ret)
  goto free_serdev;

 ret = gb_fw_init(bg);
 if (ret)
  goto free_hdlc;

 ret = gb_greybus_init(bg);
 if (ret)
  goto free_fw;

 gb_beagleplay_start_svc(bg);

 return 0;

free_fw:
 gb_fw_deinit(bg);
free_hdlc:
 hdlc_deinit(bg);
free_serdev:
 gb_serdev_deinit(bg);
 return ret;
}

static void gb_beagleplay_remove(struct serdev_device *serdev)
{
 struct gb_beagleplay *bg = serdev_device_get_drvdata(serdev);

 gb_fw_deinit(bg);
 gb_greybus_deinit(bg);
 gb_beagleplay_stop_svc(bg);
 hdlc_deinit(bg);
 gb_serdev_deinit(bg);
}

static const struct of_device_id gb_beagleplay_of_match[] = {
 {
  .compatible = "ti,cc1352p7",
 },
 {},
};
MODULE_DEVICE_TABLE(of, gb_beagleplay_of_match);

static struct serdev_device_driver gb_beagleplay_driver = {
 .probe = gb_beagleplay_probe,
 .remove = gb_beagleplay_remove,
 .driver = {
  .name = "gb_beagleplay",
  .of_match_table = gb_beagleplay_of_match,
 },
};

module_serdev_device_driver(gb_beagleplay_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ayush Singh ");
MODULE_DESCRIPTION("A Greybus driver for BeaglePlay");