text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   *	linux/drivers/net/wireless/libertas/if_spi.c
   *
   *	Driver for Marvell SPI WLAN cards.
   *
   *	Copyright 2008 Analog Devices Inc.
   *
   *	Authors:
   *	Andrey Yurovsky <andrey@cozybit.com>
   *	Colin McCabe <colin@cozybit.com>
   *
   *	Inspired by if_sdio.c, Copyright 2007-2008 Pierre Ossman
   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/hardirq.h>
  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/firmware.h>
  #include <linux/jiffies.h>
  #include <linux/list.h>
  #include <linux/netdevice.h>
  #include <linux/slab.h>
  #include <linux/spi/libertas_spi.h>
  #include <linux/spi/spi.h>
  
  #include "host.h"
  #include "decl.h"
  #include "defs.h"
  #include "dev.h"
  #include "if_spi.h"
  
  struct if_spi_packet {
  	struct list_head		list;
  	u16				blen;
  	u8				buffer[] __aligned(4);
  };
  
  struct if_spi_card {
  	struct spi_device		*spi;
  	struct lbs_private		*priv;
  	struct libertas_spi_platform_data *pdata;
  
  	/* The card ID and card revision, as reported by the hardware. */
  	u16				card_id;
  	u8				card_rev;
  
  	/* The last time that we initiated an SPU operation */
  	unsigned long			prev_xfer_time;
  
  	int				use_dummy_writes;
  	unsigned long			spu_port_delay;
  	unsigned long			spu_reg_delay;
  
  	/* Handles all SPI communication (except for FW load) */
  	struct workqueue_struct		*workqueue;
  	struct work_struct		packet_work;
  	struct work_struct		resume_work;
  
  	u8				cmd_buffer[IF_SPI_CMD_BUF_SIZE];
  
  	/* A buffer of incoming packets from libertas core.
  	 * Since we can't sleep in hw_host_to_card, we have to buffer
  	 * them. */
  	struct list_head		cmd_packet_list;
  	struct list_head		data_packet_list;
  
  	/* Protects cmd_packet_list and data_packet_list */
  	spinlock_t			buffer_lock;
  
  	/* True is card suspended */
  	u8				suspended;
  };
  
  static void free_if_spi_card(struct if_spi_card *card)
  {
  	struct list_head *cursor, *next;
  	struct if_spi_packet *packet;
  
  	list_for_each_safe(cursor, next, &card->cmd_packet_list) {
  		packet = container_of(cursor, struct if_spi_packet, list);
  		list_del(&packet->list);
  		kfree(packet);
  	}
  	list_for_each_safe(cursor, next, &card->data_packet_list) {
  		packet = container_of(cursor, struct if_spi_packet, list);
  		list_del(&packet->list);
  		kfree(packet);
  	}
  	kfree(card);
  }
  
  #define MODEL_8385	0x04
  #define MODEL_8686	0x0b
  #define MODEL_8688	0x10
  
  static const struct lbs_fw_table fw_table[] = {
  	{ MODEL_8385, "libertas/gspi8385_helper.bin", "libertas/gspi8385.bin" },
  	{ MODEL_8385, "libertas/gspi8385_hlp.bin", "libertas/gspi8385.bin" },
  	{ MODEL_8686, "libertas/gspi8686_v9_helper.bin", "libertas/gspi8686_v9.bin" },
  	{ MODEL_8686, "libertas/gspi8686_hlp.bin", "libertas/gspi8686.bin" },
  	{ MODEL_8688, "libertas/gspi8688_helper.bin", "libertas/gspi8688.bin" },
  	{ 0, NULL, NULL }
  };
  MODULE_FIRMWARE("libertas/gspi8385_helper.bin");
  MODULE_FIRMWARE("libertas/gspi8385_hlp.bin");
  MODULE_FIRMWARE("libertas/gspi8385.bin");
  MODULE_FIRMWARE("libertas/gspi8686_v9_helper.bin");
  MODULE_FIRMWARE("libertas/gspi8686_v9.bin");
  MODULE_FIRMWARE("libertas/gspi8686_hlp.bin");
  MODULE_FIRMWARE("libertas/gspi8686.bin");
  MODULE_FIRMWARE("libertas/gspi8688_helper.bin");
  MODULE_FIRMWARE("libertas/gspi8688.bin");
  
  
  /*
   * SPI Interface Unit Routines
   *
   * The SPU sits between the host and the WLAN module.
   * All communication with the firmware is through SPU transactions.
   *
   * First we have to put a SPU register name on the bus. Then we can
   * either read from or write to that register.
   *
   */
  
  static void spu_transaction_init(struct if_spi_card *card)
  {
  	if (!time_after(jiffies, card->prev_xfer_time + 1)) {
  		/* Unfortunately, the SPU requires a delay between successive
  		 * transactions. If our last transaction was more than a jiffy
  		 * ago, we have obviously already delayed enough.
  		 * If not, we have to busy-wait to be on the safe side. */
  		ndelay(400);
  	}
  }
  
  static void spu_transaction_finish(struct if_spi_card *card)
  {
  	card->prev_xfer_time = jiffies;
  }
  
  /*
   * Write out a byte buffer to an SPI register,
   * using a series of 16-bit transfers.
   */
  static int spu_write(struct if_spi_card *card, u16 reg, const u8 *buf, int len)
  {
  	int err = 0;
  	__le16 reg_out = cpu_to_le16(reg | IF_SPI_WRITE_OPERATION_MASK);
  	struct spi_message m;
  	struct spi_transfer reg_trans;
  	struct spi_transfer data_trans;
  
  	spi_message_init(&m);
  	memset(&reg_trans, 0, sizeof(reg_trans));
  	memset(&data_trans, 0, sizeof(data_trans));
  
  	/* You must give an even number of bytes to the SPU, even if it
  	 * doesn't care about the last one.  */
  	BUG_ON(len & 0x1);
  
  	spu_transaction_init(card);
  
  	/* write SPU register index */
  	reg_trans.tx_buf = &reg_out;
  	reg_trans.len = sizeof(reg_out);
  
  	data_trans.tx_buf = buf;
  	data_trans.len = len;
  
  	spi_message_add_tail(&reg_trans, &m);
  	spi_message_add_tail(&data_trans, &m);
  
  	err = spi_sync(card->spi, &m);
  	spu_transaction_finish(card);
  	return err;
  }
  
  static inline int spu_write_u16(struct if_spi_card *card, u16 reg, u16 val)
  {
  	__le16 buff;
  
  	buff = cpu_to_le16(val);
  	return spu_write(card, reg, (u8 *)&buff, sizeof(u16));
  }
  
  static inline int spu_reg_is_port_reg(u16 reg)
  {
  	switch (reg) {
  	case IF_SPI_IO_RDWRPORT_REG:
  	case IF_SPI_CMD_RDWRPORT_REG:
  	case IF_SPI_DATA_RDWRPORT_REG:
  		return 1;
  	default:
  		return 0;
  	}
  }
  
  static int spu_read(struct if_spi_card *card, u16 reg, u8 *buf, int len)
  {
  	unsigned int delay;
  	int err = 0;
  	__le16 reg_out = cpu_to_le16(reg | IF_SPI_READ_OPERATION_MASK);
  	struct spi_message m;
  	struct spi_transfer reg_trans;
  	struct spi_transfer dummy_trans;
  	struct spi_transfer data_trans;
  
  	/*
  	 * You must take an even number of bytes from the SPU, even if you
  	 * don't care about the last one.
  	 */
  	BUG_ON(len & 0x1);
  
  	spu_transaction_init(card);
  
  	spi_message_init(&m);
  	memset(&reg_trans, 0, sizeof(reg_trans));
  	memset(&dummy_trans, 0, sizeof(dummy_trans));
  	memset(&data_trans, 0, sizeof(data_trans));
  
  	/* write SPU register index */
  	reg_trans.tx_buf = &reg_out;
  	reg_trans.len = sizeof(reg_out);
  	spi_message_add_tail(&reg_trans, &m);
  
  	delay = spu_reg_is_port_reg(reg) ? card->spu_port_delay :
  						card->spu_reg_delay;
  	if (card->use_dummy_writes) {
  		/* Clock in dummy cycles while the SPU fills the FIFO */
  		dummy_trans.len = delay / 8;
  		spi_message_add_tail(&dummy_trans, &m);
  	} else {
  		/* Busy-wait while the SPU fills the FIFO */
  		reg_trans.delay.value =
  			DIV_ROUND_UP((100 + (delay * 10)), 1000);
  		reg_trans.delay.unit = SPI_DELAY_UNIT_USECS;
  	}
  
  	/* read in data */
  	data_trans.rx_buf = buf;
  	data_trans.len = len;
  	spi_message_add_tail(&data_trans, &m);
  
  	err = spi_sync(card->spi, &m);
  	spu_transaction_finish(card);
  	return err;
  }
  
  /* Read 16 bits from an SPI register */
  static inline int spu_read_u16(struct if_spi_card *card, u16 reg, u16 *val)
  {
  	__le16 buf;
  	int ret;
  
  	ret = spu_read(card, reg, (u8 *)&buf, sizeof(buf));
  	if (ret == 0)
  		*val = le16_to_cpup(&buf);
  	return ret;
  }
  
  /*
   * Read 32 bits from an SPI register.
   * The low 16 bits are read first.
   */
  static int spu_read_u32(struct if_spi_card *card, u16 reg, u32 *val)
  {
  	__le32 buf;
  	int err;
  
  	err = spu_read(card, reg, (u8 *)&buf, sizeof(buf));
  	if (!err)
  		*val = le32_to_cpup(&buf);
  	return err;
  }
  
  /*
   * Keep reading 16 bits from an SPI register until you get the correct result.
   *
   * If mask = 0, the correct result is any non-zero number.
   * If mask != 0, the correct result is any number where
   * number & target_mask == target
   *
   * Returns -ETIMEDOUT if a second passes without the correct result.
   */
  static int spu_wait_for_u16(struct if_spi_card *card, u16 reg,
  			u16 target_mask, u16 target)
  {
  	int err;
  	unsigned long timeout = jiffies + 5*HZ;
  	while (1) {
  		u16 val;
  		err = spu_read_u16(card, reg, &val);
  		if (err)
  			return err;
  		if (target_mask) {
  			if ((val & target_mask) == target)
  				return 0;
  		} else {
  			if (val)
  				return 0;
  		}
  		udelay(100);
  		if (time_after(jiffies, timeout)) {
  			pr_err("%s: timeout with val=%02x, target_mask=%02x, target=%02x\n",
  			       __func__, val, target_mask, target);
  			return -ETIMEDOUT;
  		}
  	}
  }
  
  /*
   * Read 16 bits from an SPI register until you receive a specific value.
   * Returns -ETIMEDOUT if a 4 tries pass without success.
   */
  static int spu_wait_for_u32(struct if_spi_card *card, u32 reg, u32 target)
  {
  	int err, try;
  	for (try = 0; try < 4; ++try) {
  		u32 val = 0;
  		err = spu_read_u32(card, reg, &val);
  		if (err)
  			return err;
  		if (val == target)
  			return 0;
  		mdelay(100);
  	}
  	return -ETIMEDOUT;
  }
  
  static int spu_set_interrupt_mode(struct if_spi_card *card,
  			   int suppress_host_int,
  			   int auto_int)
  {
  	int err = 0;
  
  	/*
  	 * We can suppress a host interrupt by clearing the appropriate
  	 * bit in the "host interrupt status mask" register
  	 */
  	if (suppress_host_int) {
  		err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_MASK_REG, 0);
  		if (err)
  			return err;
  	} else {
  		err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_MASK_REG,
  			      IF_SPI_HISM_TX_DOWNLOAD_RDY |
  			      IF_SPI_HISM_RX_UPLOAD_RDY |
  			      IF_SPI_HISM_CMD_DOWNLOAD_RDY |
  			      IF_SPI_HISM_CARDEVENT |
  			      IF_SPI_HISM_CMD_UPLOAD_RDY);
  		if (err)
  			return err;
  	}
  
  	/*
  	 * If auto-interrupts are on, the completion of certain transactions
  	 * will trigger an interrupt automatically. If auto-interrupts
  	 * are off, we need to set the "Card Interrupt Cause" register to
  	 * trigger a card interrupt.
  	 */
  	if (auto_int) {
  		err = spu_write_u16(card, IF_SPI_HOST_INT_CTRL_REG,
  				IF_SPI_HICT_TX_DOWNLOAD_OVER_AUTO |
  				IF_SPI_HICT_RX_UPLOAD_OVER_AUTO |
  				IF_SPI_HICT_CMD_DOWNLOAD_OVER_AUTO |
  				IF_SPI_HICT_CMD_UPLOAD_OVER_AUTO);
  		if (err)
  			return err;
  	} else {
  		err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_MASK_REG, 0);
  		if (err)
  			return err;
  	}
  	return err;
  }
  
  static int spu_get_chip_revision(struct if_spi_card *card,
  				  u16 *card_id, u8 *card_rev)
  {
  	int err = 0;
  	u32 dev_ctrl;
  	err = spu_read_u32(card, IF_SPI_DEVICEID_CTRL_REG, &dev_ctrl);
  	if (err)
  		return err;
  	*card_id = IF_SPI_DEVICEID_CTRL_REG_TO_CARD_ID(dev_ctrl);
  	*card_rev = IF_SPI_DEVICEID_CTRL_REG_TO_CARD_REV(dev_ctrl);
  	return err;
  }
  
  static int spu_set_bus_mode(struct if_spi_card *card, u16 mode)
  {
  	int err = 0;
  	u16 rval;
  	/* set bus mode */
  	err = spu_write_u16(card, IF_SPI_SPU_BUS_MODE_REG, mode);
  	if (err)
  		return err;
  	/* Check that we were able to read back what we just wrote. */
  	err = spu_read_u16(card, IF_SPI_SPU_BUS_MODE_REG, &rval);
  	if (err)
  		return err;
  	if ((rval & 0xF) != mode) {
  		pr_err("Can't read bus mode register\n");
  		return -EIO;
  	}
  	return 0;
  }
  
  static int spu_init(struct if_spi_card *card, int use_dummy_writes)
  {
  	int err = 0;
  	u32 delay;
  
  	/*
  	 * We have to start up in timed delay mode so that we can safely
  	 * read the Delay Read Register.
  	 */
  	card->use_dummy_writes = 0;
  	err = spu_set_bus_mode(card,
  				IF_SPI_BUS_MODE_SPI_CLOCK_PHASE_RISING |
  				IF_SPI_BUS_MODE_DELAY_METHOD_TIMED |
  				IF_SPI_BUS_MODE_16_BIT_ADDRESS_16_BIT_DATA);
  	if (err)
  		return err;
  	card->spu_port_delay = 1000;
  	card->spu_reg_delay = 1000;
  	err = spu_read_u32(card, IF_SPI_DELAY_READ_REG, &delay);
  	if (err)
  		return err;
  	card->spu_port_delay = delay & 0x0000ffff;
  	card->spu_reg_delay = (delay & 0xffff0000) >> 16;
  
  	/* If dummy clock delay mode has been requested, switch to it now */
  	if (use_dummy_writes) {
  		card->use_dummy_writes = 1;
  		err = spu_set_bus_mode(card,
  				IF_SPI_BUS_MODE_SPI_CLOCK_PHASE_RISING |
  				IF_SPI_BUS_MODE_DELAY_METHOD_DUMMY_CLOCK |
  				IF_SPI_BUS_MODE_16_BIT_ADDRESS_16_BIT_DATA);
  		if (err)
  			return err;
  	}
  
  	lbs_deb_spi("Initialized SPU unit. "
  		    "spu_port_delay=0x%04lx, spu_reg_delay=0x%04lx\n",
  		    card->spu_port_delay, card->spu_reg_delay);
  	return err;
  }
  
  /*
   * Firmware Loading
   */
  
  static int if_spi_prog_helper_firmware(struct if_spi_card *card,
  					const struct firmware *firmware)
  {
  	int err = 0;
  	int bytes_remaining;
  	const u8 *fw;
  	u8 temp[HELPER_FW_LOAD_CHUNK_SZ];
  
  	err = spu_set_interrupt_mode(card, 1, 0);
  	if (err)
  		goto out;
  
  	bytes_remaining = firmware->size;
  	fw = firmware->data;
  
  	/* Load helper firmware image */
  	while (bytes_remaining > 0) {
  		/*
  		 * Scratch pad 1 should contain the number of bytes we
  		 * want to download to the firmware
  		 */
  		err = spu_write_u16(card, IF_SPI_SCRATCH_1_REG,
  					HELPER_FW_LOAD_CHUNK_SZ);
  		if (err)
  			goto out;
  
  		err = spu_wait_for_u16(card, IF_SPI_HOST_INT_STATUS_REG,
  					IF_SPI_HIST_CMD_DOWNLOAD_RDY,
  					IF_SPI_HIST_CMD_DOWNLOAD_RDY);
  		if (err)
  			goto out;
  
  		/*
  		 * Feed the data into the command read/write port reg
  		 * in chunks of 64 bytes
  		 */
  		memset(temp, 0, sizeof(temp));
  		memcpy(temp, fw,
  		       min(bytes_remaining, HELPER_FW_LOAD_CHUNK_SZ));
  		mdelay(10);
  		err = spu_write(card, IF_SPI_CMD_RDWRPORT_REG,
  					temp, HELPER_FW_LOAD_CHUNK_SZ);
  		if (err)
  			goto out;
  
  		/* Interrupt the boot code */
  		err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_REG, 0);
  		if (err)
  			goto out;
  		err = spu_write_u16(card, IF_SPI_CARD_INT_CAUSE_REG,
  				       IF_SPI_CIC_CMD_DOWNLOAD_OVER);
  		if (err)
  			goto out;
  		bytes_remaining -= HELPER_FW_LOAD_CHUNK_SZ;
  		fw += HELPER_FW_LOAD_CHUNK_SZ;
  	}
  
  	/*
  	 * Once the helper / single stage firmware download is complete,
  	 * write 0 to scratch pad 1 and interrupt the
  	 * bootloader. This completes the helper download.
  	 */
  	err = spu_write_u16(card, IF_SPI_SCRATCH_1_REG, FIRMWARE_DNLD_OK);
  	if (err)
  		goto out;
  	err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_REG, 0);
  	if (err)
  		goto out;
  	err = spu_write_u16(card, IF_SPI_CARD_INT_CAUSE_REG,
  				IF_SPI_CIC_CMD_DOWNLOAD_OVER);
  out:
  	if (err)
  		pr_err("failed to load helper firmware (err=%d)\n", err);
  
  	return err;
  }
  
  /*
   * Returns the length of the next packet the firmware expects us to send.
   * Sets crc_err if the previous transfer had a CRC error.
   */
  static int if_spi_prog_main_firmware_check_len(struct if_spi_card *card,
  						int *crc_err)
  {
  	u16 len;
  	int err = 0;
  
  	/*
  	 * wait until the host interrupt status register indicates
  	 * that we are ready to download
  	 */
  	err = spu_wait_for_u16(card, IF_SPI_HOST_INT_STATUS_REG,
  				IF_SPI_HIST_CMD_DOWNLOAD_RDY,
  				IF_SPI_HIST_CMD_DOWNLOAD_RDY);
  	if (err) {
  		pr_err("timed out waiting for host_int_status\n");
  		return err;
  	}
  
  	/* Ask the device how many bytes of firmware it wants. */
  	err = spu_read_u16(card, IF_SPI_SCRATCH_1_REG, &len);
  	if (err)
  		return err;
  
  	if (len > IF_SPI_CMD_BUF_SIZE) {
  		pr_err("firmware load device requested a larger transfer than we are prepared to handle (len = %d)\n",
  		       len);
  		return -EIO;
  	}
  	if (len & 0x1) {
  		lbs_deb_spi("%s: crc error\n", __func__);
  		len &= ~0x1;
  		*crc_err = 1;
  	} else
  		*crc_err = 0;
  
  	return len;
  }
  
  static int if_spi_prog_main_firmware(struct if_spi_card *card,
  					const struct firmware *firmware)
  {
  	struct lbs_private *priv = card->priv;
  	int len, prev_len;
  	int bytes, crc_err = 0, err = 0;
  	const u8 *fw;
  	u16 num_crc_errs;
  
  	err = spu_set_interrupt_mode(card, 1, 0);
  	if (err)
  		goto out;
  
  	err = spu_wait_for_u16(card, IF_SPI_SCRATCH_1_REG, 0, 0);
  	if (err) {
  		netdev_err(priv->dev,
  			   "%s: timed out waiting for initial scratch reg = 0\n",
  			   __func__);
  		goto out;
  	}
  
  	num_crc_errs = 0;
  	prev_len = 0;
  	bytes = firmware->size;
  	fw = firmware->data;
  	while ((len = if_spi_prog_main_firmware_check_len(card, &crc_err))) {
  		if (len < 0) {
  			err = len;
  			goto out;
  		}
  		if (bytes < 0) {
  			/*
  			 * If there are no more bytes left, we would normally
  			 * expect to have terminated with len = 0
  			 */
  			netdev_err(priv->dev,
  				   "Firmware load wants more bytes than we have to offer.\n");
  			break;
  		}
  		if (crc_err) {
  			/* Previous transfer failed. */
  			if (++num_crc_errs > MAX_MAIN_FW_LOAD_CRC_ERR) {
  				pr_err("Too many CRC errors encountered in firmware load.\n");
  				err = -EIO;
  				goto out;
  			}
  		} else {
  			/* Previous transfer succeeded. Advance counters. */
  			bytes -= prev_len;
  			fw += prev_len;
  		}
  		if (bytes < len) {
  			memset(card->cmd_buffer, 0, len);
  			memcpy(card->cmd_buffer, fw, bytes);
  		} else
  			memcpy(card->cmd_buffer, fw, len);
  
  		err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_REG, 0);
  		if (err)
  			goto out;
  		err = spu_write(card, IF_SPI_CMD_RDWRPORT_REG,
  				card->cmd_buffer, len);
  		if (err)
  			goto out;
  		err = spu_write_u16(card, IF_SPI_CARD_INT_CAUSE_REG ,
  					IF_SPI_CIC_CMD_DOWNLOAD_OVER);
  		if (err)
  			goto out;
  		prev_len = len;
  	}
  	if (bytes > prev_len) {
  		pr_err("firmware load wants fewer bytes than we have to offer\n");
  	}
  
  	/* Confirm firmware download */
  	err = spu_wait_for_u32(card, IF_SPI_SCRATCH_4_REG,
  					SUCCESSFUL_FW_DOWNLOAD_MAGIC);
  	if (err) {
  		pr_err("failed to confirm the firmware download\n");
  		goto out;
  	}
  
  out:
  	if (err)
  		pr_err("failed to load firmware (err=%d)\n", err);
  
  	return err;
  }
  
  /*
   * SPI Transfer Thread
   *
   * The SPI worker handles all SPI transfers, so there is no need for a lock.
   */
  
  /* Move a command from the card to the host */
  static int if_spi_c2h_cmd(struct if_spi_card *card)
  {
  	struct lbs_private *priv = card->priv;
  	unsigned long flags;
  	int err = 0;
  	u16 len;
  	u8 i;
  
  	/*
  	 * We need a buffer big enough to handle whatever people send to
  	 * hw_host_to_card
  	 */
  	BUILD_BUG_ON(IF_SPI_CMD_BUF_SIZE < LBS_CMD_BUFFER_SIZE);
  	BUILD_BUG_ON(IF_SPI_CMD_BUF_SIZE < LBS_UPLD_SIZE);
  
  	/*
  	 * It's just annoying if the buffer size isn't a multiple of 4, because
  	 * then we might have len < IF_SPI_CMD_BUF_SIZE but
  	 * ALIGN(len, 4) > IF_SPI_CMD_BUF_SIZE
  	 */
  	BUILD_BUG_ON(IF_SPI_CMD_BUF_SIZE % 4 != 0);
  
  	/* How many bytes are there to read? */
  	err = spu_read_u16(card, IF_SPI_SCRATCH_2_REG, &len);
  	if (err)
  		goto out;
  	if (!len) {
  		netdev_err(priv->dev, "%s: error: card has no data for host\n",
  			   __func__);
  		err = -EINVAL;
  		goto out;
  	} else if (len > IF_SPI_CMD_BUF_SIZE) {
  		netdev_err(priv->dev,
  			   "%s: error: response packet too large: %d bytes, but maximum is %d\n",
  			   __func__, len, IF_SPI_CMD_BUF_SIZE);
  		err = -EINVAL;
  		goto out;
  	}
  
  	/* Read the data from the WLAN module into our command buffer */
  	err = spu_read(card, IF_SPI_CMD_RDWRPORT_REG,
  				card->cmd_buffer, ALIGN(len, 4));
  	if (err)
  		goto out;
  
  	spin_lock_irqsave(&priv->driver_lock, flags);
  	i = (priv->resp_idx == 0) ? 1 : 0;
  	BUG_ON(priv->resp_len[i]);
  	priv->resp_len[i] = len;
  	memcpy(priv->resp_buf[i], card->cmd_buffer, len);
  	lbs_notify_command_response(priv, i);
  	spin_unlock_irqrestore(&priv->driver_lock, flags);
  
  out:
  	if (err)
  		netdev_err(priv->dev, "%s: err=%d\n", __func__, err);
  
  	return err;
  }
  
  /* Move data from the card to the host */
  static int if_spi_c2h_data(struct if_spi_card *card)
  {
  	struct lbs_private *priv = card->priv;
  	struct sk_buff *skb;
  	char *data;
  	u16 len;
  	int err = 0;
  
  	/* How many bytes are there to read? */
  	err = spu_read_u16(card, IF_SPI_SCRATCH_1_REG, &len);
  	if (err)
  		goto out;
  	if (!len) {
  		netdev_err(priv->dev, "%s: error: card has no data for host\n",
  			   __func__);
  		err = -EINVAL;
  		goto out;
  	} else if (len > MRVDRV_ETH_RX_PACKET_BUFFER_SIZE) {
  		netdev_err(priv->dev,
  			   "%s: error: card has %d bytes of data, but our maximum skb size is %zu\n",
  			   __func__, len, MRVDRV_ETH_RX_PACKET_BUFFER_SIZE);
  		err = -EINVAL;
  		goto out;
  	}
  
  	/* TODO: should we allocate a smaller skb if we have less data? */
  	skb = dev_alloc_skb(MRVDRV_ETH_RX_PACKET_BUFFER_SIZE);
  	if (!skb) {
  		err = -ENOBUFS;
  		goto out;
  	}
  	skb_reserve(skb, IPFIELD_ALIGN_OFFSET);
  	data = skb_put(skb, len);
  
  	/* Read the data from the WLAN module into our skb... */
  	err = spu_read(card, IF_SPI_DATA_RDWRPORT_REG, data, ALIGN(len, 4));
  	if (err) {
  		dev_kfree_skb(skb);
  		goto out;
  	}
  
  	/* pass the SKB to libertas */
  	err = lbs_process_rxed_packet(card->priv, skb);
  	/* lbs_process_rxed_packet() consumes the skb */
  
  out:
  	if (err)
  		netdev_err(priv->dev, "%s: err=%d\n", __func__, err);
  
  	return err;
  }
  
  /* Move data or a command from the host to the card. */
  static void if_spi_h2c(struct if_spi_card *card,
  			struct if_spi_packet *packet, int type)
  {
  	struct lbs_private *priv = card->priv;
  	int err = 0;
  	u16 port_reg;
  
  	switch (type) {
  	case MVMS_DAT:
  		port_reg = IF_SPI_DATA_RDWRPORT_REG;
  		break;
  	case MVMS_CMD:
  		port_reg = IF_SPI_CMD_RDWRPORT_REG;
  		break;
  	default:
  		netdev_err(priv->dev, "can't transfer buffer of type %d\n",
  			   type);
  		err = -EINVAL;
  		goto out;
  	}
  
  	/* Write the data to the card */
  	err = spu_write(card, port_reg, packet->buffer, packet->blen);
  	if (err)
  		goto out;
  
  out:
  	kfree(packet);
  
  	if (err)
  		netdev_err(priv->dev, "%s: error %d\n", __func__, err);
  }
  
  /* Inform the host about a card event */
  static void if_spi_e2h(struct if_spi_card *card)
  {
  	int err = 0;
  	u32 cause;
  	struct lbs_private *priv = card->priv;
  
  	err = spu_read_u32(card, IF_SPI_SCRATCH_3_REG, &cause);
  	if (err)
  		goto out;
  
  	/* re-enable the card event interrupt */
  	spu_write_u16(card, IF_SPI_HOST_INT_STATUS_REG,
  			~IF_SPI_HICU_CARD_EVENT);
  
  	/* generate a card interrupt */
  	spu_write_u16(card, IF_SPI_CARD_INT_CAUSE_REG, IF_SPI_CIC_HOST_EVENT);
  
  	lbs_queue_event(priv, cause & 0xff);
  out:
  	if (err)
  		netdev_err(priv->dev, "%s: error %d\n", __func__, err);
  }
  
  static void if_spi_host_to_card_worker(struct work_struct *work)
  {
  	int err;
  	struct if_spi_card *card;
  	u16 hiStatus;
  	unsigned long flags;
  	struct if_spi_packet *packet;
  	struct lbs_private *priv;
  
  	card = container_of(work, struct if_spi_card, packet_work);
  	priv = card->priv;
  
  	/*
  	 * Read the host interrupt status register to see what we
  	 * can do.
  	 */
  	err = spu_read_u16(card, IF_SPI_HOST_INT_STATUS_REG,
  				&hiStatus);
  	if (err) {
  		netdev_err(priv->dev, "I/O error\n");
  		goto err;
  	}
  
  	if (hiStatus & IF_SPI_HIST_CMD_UPLOAD_RDY) {
  		err = if_spi_c2h_cmd(card);
  		if (err)
  			goto err;
  	}
  	if (hiStatus & IF_SPI_HIST_RX_UPLOAD_RDY) {
  		err = if_spi_c2h_data(card);
  		if (err)
  			goto err;
  	}
  
  	/*
  	 * workaround: in PS mode, the card does not set the Command
  	 * Download Ready bit, but it sets TX Download Ready.
  	 */
  	if (hiStatus & IF_SPI_HIST_CMD_DOWNLOAD_RDY ||
  	   (card->priv->psstate != PS_STATE_FULL_POWER &&
  	    (hiStatus & IF_SPI_HIST_TX_DOWNLOAD_RDY))) {
  		/*
  		 * This means two things. First of all,
  		 * if there was a previous command sent, the card has
  		 * successfully received it.
  		 * Secondly, it is now ready to download another
  		 * command.
  		 */
  		lbs_host_to_card_done(card->priv);
  
  		/* Do we have any command packets from the host to send? */
  		packet = NULL;
  		spin_lock_irqsave(&card->buffer_lock, flags);
  		if (!list_empty(&card->cmd_packet_list)) {
  			packet = (struct if_spi_packet *)(card->
  					cmd_packet_list.next);
  			list_del(&packet->list);
  		}
  		spin_unlock_irqrestore(&card->buffer_lock, flags);
  
  		if (packet)
  			if_spi_h2c(card, packet, MVMS_CMD);
  	}
  	if (hiStatus & IF_SPI_HIST_TX_DOWNLOAD_RDY) {
  		/* Do we have any data packets from the host to send? */
  		packet = NULL;
  		spin_lock_irqsave(&card->buffer_lock, flags);
  		if (!list_empty(&card->data_packet_list)) {
  			packet = (struct if_spi_packet *)(card->
  					data_packet_list.next);
  			list_del(&packet->list);
  		}
  		spin_unlock_irqrestore(&card->buffer_lock, flags);
  
  		if (packet)
  			if_spi_h2c(card, packet, MVMS_DAT);
  	}
  	if (hiStatus & IF_SPI_HIST_CARD_EVENT)
  		if_spi_e2h(card);
  
  err:
  	if (err)
  		netdev_err(priv->dev, "%s: got error %d\n", __func__, err);
  }
  
  /*
   * Host to Card
   *
   * Called from Libertas to transfer some data to the WLAN device
   * We can't sleep here.
   */
  static int if_spi_host_to_card(struct lbs_private *priv,
  				u8 type, u8 *buf, u16 nb)
  {
  	int err = 0;
  	unsigned long flags;
  	struct if_spi_card *card = priv->card;
  	struct if_spi_packet *packet;
  	u16 blen;
  
  	if (nb == 0) {
  		netdev_err(priv->dev, "%s: invalid size requested: %d\n",
  			   __func__, nb);
  		err = -EINVAL;
  		goto out;
  	}
  	blen = ALIGN(nb, 4);
  	packet = kzalloc(sizeof(struct if_spi_packet) + blen, GFP_ATOMIC);
  	if (!packet) {
  		err = -ENOMEM;
  		goto out;
  	}
  	packet->blen = blen;
  	memcpy(packet->buffer, buf, nb);
  	memset(packet->buffer + nb, 0, blen - nb);
  
  	switch (type) {
  	case MVMS_CMD:
  		priv->dnld_sent = DNLD_CMD_SENT;
  		spin_lock_irqsave(&card->buffer_lock, flags);
  		list_add_tail(&packet->list, &card->cmd_packet_list);
  		spin_unlock_irqrestore(&card->buffer_lock, flags);
  		break;
  	case MVMS_DAT:
  		priv->dnld_sent = DNLD_DATA_SENT;
  		spin_lock_irqsave(&card->buffer_lock, flags);
  		list_add_tail(&packet->list, &card->data_packet_list);
  		spin_unlock_irqrestore(&card->buffer_lock, flags);
  		break;
  	default:
  		kfree(packet);
  		netdev_err(priv->dev, "can't transfer buffer of type %d\n",
  			   type);
  		err = -EINVAL;
  		break;
  	}
  
  	/* Queue spi xfer work */
  	queue_work(card->workqueue, &card->packet_work);
  out:
  	return err;
  }
  
  /*
   * Host Interrupts
   *
   * Service incoming interrupts from the WLAN device. We can't sleep here, so
   * don't try to talk on the SPI bus, just queue the SPI xfer work.
   */
  static irqreturn_t if_spi_host_interrupt(int irq, void *dev_id)
  {
  	struct if_spi_card *card = dev_id;
  
  	queue_work(card->workqueue, &card->packet_work);
  
  	return IRQ_HANDLED;
  }
  
  /*
   * SPI callbacks
   */
  
  static int if_spi_init_card(struct if_spi_card *card)
  {
  	struct lbs_private *priv = card->priv;
  	int err, i;
  	u32 scratch;
  	const struct firmware *helper = NULL;
  	const struct firmware *mainfw = NULL;
  
  	err = spu_init(card, card->pdata->use_dummy_writes);
  	if (err)
  		goto out;
  	err = spu_get_chip_revision(card, &card->card_id, &card->card_rev);
  	if (err)
  		goto out;
  
  	err = spu_read_u32(card, IF_SPI_SCRATCH_4_REG, &scratch);
  	if (err)
  		goto out;
  	if (scratch == SUCCESSFUL_FW_DOWNLOAD_MAGIC)
  		lbs_deb_spi("Firmware is already loaded for "
  			    "Marvell WLAN 802.11 adapter\n");
  	else {
  		/* Check if we support this card */
  		for (i = 0; i < ARRAY_SIZE(fw_table); i++) {
  			if (card->card_id == fw_table[i].model)
  				break;
  		}
  		if (i == ARRAY_SIZE(fw_table)) {
  			netdev_err(priv->dev, "Unsupported chip_id: 0x%02x\n",
  				   card->card_id);
  			err = -ENODEV;
  			goto out;
  		}
  
  		err = lbs_get_firmware(&card->spi->dev, card->card_id,
  					&fw_table[0], &helper, &mainfw);
  		if (err) {
  			netdev_err(priv->dev, "failed to find firmware (%d)\n",
  				   err);
  			goto out;
  		}
  
  		lbs_deb_spi("Initializing FW for Marvell WLAN 802.11 adapter "
  				"(chip_id = 0x%04x, chip_rev = 0x%02x) "
  				"attached to SPI bus_num %d, chip_select %d. "
  				"spi->max_speed_hz=%d\n",
  				card->card_id, card->card_rev,
  				card->spi->master->bus_num,
  				card->spi->chip_select,
  				card->spi->max_speed_hz);
  		err = if_spi_prog_helper_firmware(card, helper);
  		if (err)
  			goto out;
  		err = if_spi_prog_main_firmware(card, mainfw);
  		if (err)
  			goto out;
  		lbs_deb_spi("loaded FW for Marvell WLAN 802.11 adapter\n");
  	}
  
  	err = spu_set_interrupt_mode(card, 0, 1);
  	if (err)
  		goto out;
  
  out:
  	return err;
  }
  
  static void if_spi_resume_worker(struct work_struct *work)
  {
  	struct if_spi_card *card;
  
  	card = container_of(work, struct if_spi_card, resume_work);
  
  	if (card->suspended) {
  		if (card->pdata->setup)
  			card->pdata->setup(card->spi);
  
  		/* Init card ... */
  		if_spi_init_card(card);
  
  		enable_irq(card->spi->irq);
  
  		/* And resume it ... */
  		lbs_resume(card->priv);
  
  		card->suspended = 0;
  	}
  }
  
  static int if_spi_probe(struct spi_device *spi)
  {
  	struct if_spi_card *card;
  	struct lbs_private *priv = NULL;
  	struct libertas_spi_platform_data *pdata = dev_get_platdata(&spi->dev);
  	int err = 0;
  
  	if (!pdata) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	if (pdata->setup) {
  		err = pdata->setup(spi);
  		if (err)
  			goto out;
  	}
  
  	/* Allocate card structure to represent this specific device */
  	card = kzalloc(sizeof(struct if_spi_card), GFP_KERNEL);
  	if (!card) {
  		err = -ENOMEM;
  		goto teardown;
  	}
  	spi_set_drvdata(spi, card);
  	card->pdata = pdata;
  	card->spi = spi;
  	card->prev_xfer_time = jiffies;
  
  	INIT_LIST_HEAD(&card->cmd_packet_list);
  	INIT_LIST_HEAD(&card->data_packet_list);
  	spin_lock_init(&card->buffer_lock);
  
  	/* Initialize the SPI Interface Unit */
  
  	/* Firmware load */
  	err = if_spi_init_card(card);
  	if (err)
  		goto free_card;
  
  	/*
  	 * Register our card with libertas.
  	 * This will call alloc_etherdev.
  	 */
  	priv = lbs_add_card(card, &spi->dev);
  	if (IS_ERR(priv)) {
  		err = PTR_ERR(priv);
  		goto free_card;
  	}
  	card->priv = priv;
  	priv->setup_fw_on_resume = 1;
  	priv->card = card;
  	priv->hw_host_to_card = if_spi_host_to_card;
  	priv->enter_deep_sleep = NULL;
  	priv->exit_deep_sleep = NULL;
  	priv->reset_deep_sleep_wakeup = NULL;
  	priv->fw_ready = 1;
  
  	/* Initialize interrupt handling stuff. */
  	card->workqueue = alloc_workqueue("libertas_spi", WQ_MEM_RECLAIM, 0);
  	if (!card->workqueue) {
  		err = -ENOMEM;
  		goto remove_card;
  	}
  	INIT_WORK(&card->packet_work, if_spi_host_to_card_worker);
  	INIT_WORK(&card->resume_work, if_spi_resume_worker);
  
  	err = request_irq(spi->irq, if_spi_host_interrupt,
  			IRQF_TRIGGER_FALLING, "libertas_spi", card);
  	if (err) {
  		pr_err("can't get host irq line-- request_irq failed\n");
  		goto terminate_workqueue;
  	}
  
  	/*
  	 * Start the card.
  	 * This will call register_netdev, and we'll start
  	 * getting interrupts...
  	 */
  	err = lbs_start_card(priv);
  	if (err)
  		goto release_irq;
  
  	lbs_deb_spi("Finished initializing WLAN module.\n");
  
  	/* successful exit */
  	goto out;
  
  release_irq:
  	free_irq(spi->irq, card);
  terminate_workqueue:
  	destroy_workqueue(card->workqueue);
  remove_card:
  	lbs_remove_card(priv); /* will call free_netdev */
  free_card:
  	free_if_spi_card(card);
  teardown:
  	if (pdata->teardown)
  		pdata->teardown(spi);
  out:
  	return err;
  }
  
  static int libertas_spi_remove(struct spi_device *spi)
  {
  	struct if_spi_card *card = spi_get_drvdata(spi);
  	struct lbs_private *priv = card->priv;
  
  	lbs_deb_spi("libertas_spi_remove\n");
  
  	cancel_work_sync(&card->resume_work);
  
  	lbs_stop_card(priv);
  	lbs_remove_card(priv); /* will call free_netdev */
  
  	free_irq(spi->irq, card);
  	destroy_workqueue(card->workqueue);
  	if (card->pdata->teardown)
  		card->pdata->teardown(spi);
  	free_if_spi_card(card);
  
  	return 0;
  }
  
  static int if_spi_suspend(struct device *dev)
  {
  	struct spi_device *spi = to_spi_device(dev);
  	struct if_spi_card *card = spi_get_drvdata(spi);
  
  	if (!card->suspended) {
  		lbs_suspend(card->priv);
  		flush_workqueue(card->workqueue);
  		disable_irq(spi->irq);
  
  		if (card->pdata->teardown)
  			card->pdata->teardown(spi);
  		card->suspended = 1;
  	}
  
  	return 0;
  }
  
  static int if_spi_resume(struct device *dev)
  {
  	struct spi_device *spi = to_spi_device(dev);
  	struct if_spi_card *card = spi_get_drvdata(spi);
  
  	/* Schedule delayed work */
  	schedule_work(&card->resume_work);
  
  	return 0;
  }
  
  static const struct dev_pm_ops if_spi_pm_ops = {
  	.suspend	= if_spi_suspend,
  	.resume		= if_spi_resume,
  };
  
  static struct spi_driver libertas_spi_driver = {
  	.probe	= if_spi_probe,
  	.remove = libertas_spi_remove,
  	.driver = {
  		.name	= "libertas_spi",
  		.pm	= &if_spi_pm_ops,
  	},
  };
  
  /*
   * Module functions
   */
  
  static int __init if_spi_init_module(void)
  {
  	int ret = 0;
  
  	printk(KERN_INFO "libertas_spi: Libertas SPI driver\n");
  	ret = spi_register_driver(&libertas_spi_driver);
  
  	return ret;
  }
  
  static void __exit if_spi_exit_module(void)
  {
  	spi_unregister_driver(&libertas_spi_driver);
  }
  
  module_init(if_spi_init_module);
  module_exit(if_spi_exit_module);
  
  MODULE_DESCRIPTION("Libertas SPI WLAN Driver");
  MODULE_AUTHOR("Andrey Yurovsky <andrey@cozybit.com>, "
  	      "Colin McCabe <colin@cozybit.com>");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("spi:libertas_spi");
  