text: /*
   * SPI flash interface
   *
   * Copyright (C) 2008 Atmel Corporation
   * Copyright (C) 2010 Reinhard Meyer, EMK Elektronik
   *
   * Licensed under the GPL-2 or later.
   */
  
  #include <stdlib.h>
  #include <string.h>
  #include <spi-generic.h>
  #include <spi_flash.h>
  #include <delay.h>
  #ifdef __SMM__
  #include <cpu/x86/smm.h>
  #endif
  #include "spi_flash_internal.h"
  
  static void spi_flash_addr(u32 addr, u8 *cmd)
  {
  	/* cmd[0] is actual command */
  	cmd[1] = addr >> 16;
  	cmd[2] = addr >> 8;
  	cmd[3] = addr >> 0;
  }
  
  int spi_flash_cmd(struct spi_slave *spi, u8 cmd, void *response, size_t len)
  {
  	int ret = spi_xfer(spi, &cmd, 8, response, len * 8);
  	if (ret)
  		printk(BIOS_WARNING, "SF: Failed to send command %02x: %d\n", cmd, ret);
  
  	return ret;
  }
  
  int spi_flash_cmd_read(struct spi_slave *spi, const u8 *cmd,
  		size_t cmd_len, void *data, size_t data_len)
  {
  	int ret = spi_xfer(spi, cmd, cmd_len * 8, data, data_len * 8);
  	if (ret) {
  		printk(BIOS_WARNING, "SF: Failed to send read command (%zu bytes): %d\n",
  				data_len, ret);
  	}
  
  	return ret;
  }
  
  int spi_flash_cmd_write(struct spi_slave *spi, const u8 *cmd, size_t cmd_len,
  		const void *data, size_t data_len)
  {
  	int ret;
  	u8 buff[cmd_len + data_len];
  	memcpy(buff, cmd, cmd_len);
  	memcpy(buff + cmd_len, data, data_len);
  
  	ret = spi_xfer(spi, buff, (cmd_len + data_len) * 8, NULL, 0);
  	if (ret) {
  		printk(BIOS_WARNING, "SF: Failed to send write command (%zu bytes): %d\n",
  				data_len, ret);
  	}
  
  	return ret;
  }
  
  int spi_flash_read_common(struct spi_flash *flash, const u8 *cmd,
  		size_t cmd_len, void *data, size_t data_len)
  {
  	struct spi_slave *spi = flash->spi;
  	int ret;
  
  	spi->rw = SPI_READ_FLAG;
  	spi_claim_bus(spi);
  	ret = spi_flash_cmd_read(spi, cmd, cmd_len, data, data_len);
  	spi_release_bus(spi);
  
  	return ret;
  }
  
  int spi_flash_cmd_read_fast(struct spi_flash *flash, u32 offset,
  		size_t len, void *data)
  {
  	struct spi_slave *spi = flash->spi;
  	u8 cmd[5];
  
  	cmd[0] = CMD_READ_ARRAY_FAST;
  	spi_flash_addr(offset, cmd);
  	cmd[4] = 0x00;
  
  	return spi_flash_cmd_read(spi, cmd, sizeof(cmd), data, len);
  }
  
  int spi_flash_cmd_read_slow(struct spi_flash *flash, u32 offset,
  		size_t len, void *data)
  {
  	struct spi_slave *spi = flash->spi;
  	u8 cmd[4];
  
  	cmd[0] = CMD_READ_ARRAY_SLOW;
  	spi_flash_addr(offset, cmd);
  
  	return spi_flash_cmd_read(spi, cmd, sizeof(cmd), data, len);
  }
  
  int spi_flash_cmd_poll_bit(struct spi_flash *flash, unsigned long timeout,
  			   u8 cmd, u8 poll_bit)
  {
  	struct spi_slave *spi = flash->spi;
  	unsigned long timebase;
  	int ret;
  	u8 status;
  
  	timebase = timeout;
  	do {
  		ret = spi_flash_cmd_read(spi, &cmd, 1, &status, 1);
  		if (ret)
  			return -1;
  
  		if ((status & poll_bit) == 0)
  			break;
  
  		udelay(500);
  	} while (timebase--);
  
  	if ((status & poll_bit) == 0)
  		return 0;
  
  	/* Timed out */
  	printk(BIOS_DEBUG, "SF: time out!\n");
  	return -1;
  }
  
  int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
  {
  	return spi_flash_cmd_poll_bit(flash, timeout,
  		CMD_READ_STATUS, STATUS_WIP);
  }
  
  int spi_flash_cmd_erase(struct spi_flash *flash, u8 erase_cmd,
  			u32 offset, size_t len)
  {
  	u32 start, end, erase_size;
  	int ret;
  	u8 cmd[4];
  
  	erase_size = flash->sector_size;
  	if (offset % erase_size || len % erase_size) {
  		printk(BIOS_WARNING, "SF: Erase offset/length not multiple of erase size\n");
  		return -1;
  	}
  
  	flash->spi->rw = SPI_WRITE_FLAG;
  	ret = spi_claim_bus(flash->spi);
  	if (ret) {
  		printk(BIOS_WARNING, "SF: Unable to claim SPI bus\n");
  		return ret;
  	}
  
  	cmd[0] = erase_cmd;
  	start = offset;
  	end = start + len;
  
  	while (offset < end) {
  		spi_flash_addr(offset, cmd);
  		offset += erase_size;
  
  #if CONFIG_DEBUG_SPI_FLASH
  		printk(BIOS_SPEW, "SF: erase %2x %2x %2x %2x (%x)\n", cmd[0], cmd[1],
  		      cmd[2], cmd[3], offset);
  #endif
  		ret = spi_flash_cmd(flash->spi, CMD_WRITE_ENABLE, NULL, 0);
  		if (ret)
  			goto out;
  
  		ret = spi_flash_cmd_write(flash->spi, cmd, sizeof(cmd), NULL, 0);
  		if (ret)
  			goto out;
  
  		ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PAGE_ERASE_TIMEOUT);
  		if (ret)
  			goto out;
  	}
  
  	printk(BIOS_DEBUG, "SF: Successfully erased %zu bytes @ %#x\n", len, start);
  
  out:
  	spi_release_bus(flash->spi);
  	return ret;
  }
  
  /*
   * The following table holds all device probe functions
   *
   * shift:  number of continuation bytes before the ID
   * idcode: the expected IDCODE or 0xff for non JEDEC devices
   * probe:  the function to call
   *
   * Non JEDEC devices should be ordered in the table such that
   * the probe functions with best detection algorithms come first.
   *
   * Several matching entries are permitted, they will be tried
   * in sequence until a probe function returns non NULL.
   *
   * IDCODE_CONT_LEN may be redefined if a device needs to declare a
   * larger "shift" value.  IDCODE_PART_LEN generally shouldn't be
   * changed.  This is the max number of bytes probe functions may
   * examine when looking up part-specific identification info.
   *
   * Probe functions will be given the idcode buffer starting at their
   * manu id byte (the "idcode" in the table below).  In other words,
   * all of the continuation bytes will be skipped (the "shift" below).
   */
  #define IDCODE_CONT_LEN 0
  #define IDCODE_PART_LEN 5
  static struct {
  	const u8 shift;
  	const u8 idcode;
  	struct spi_flash *(*probe) (struct spi_slave *spi, u8 *idcode);
  } flashes[] = {
  	/* Keep it sorted by define name */
  #if CONFIG_SPI_FLASH_EON
  	{ 0, 0x1c, spi_flash_probe_eon, },
  #endif
  #if CONFIG_SPI_FLASH_GIGADEVICE
  	{ 0, 0xc8, spi_flash_probe_gigadevice, },
  #endif
  #if CONFIG_SPI_FLASH_MACRONIX
  	{ 0, 0xc2, spi_flash_probe_macronix, },
  #endif
  #if CONFIG_SPI_FLASH_SPANSION
  	{ 0, 0x01, spi_flash_probe_spansion, },
  #endif
  #if CONFIG_SPI_FLASH_SST
  	{ 0, 0xbf, spi_flash_probe_sst, },
  #endif
  #if CONFIG_SPI_FLASH_STMICRO
  	{ 0, 0x20, spi_flash_probe_stmicro, },
  #endif
  #if CONFIG_SPI_FLASH_WINBOND
  	{ 0, 0xef, spi_flash_probe_winbond, },
  #endif
  	/* Keep it sorted by best detection */
  #if CONFIG_SPI_FLASH_STMICRO
  	{ 0, 0xff, spi_flash_probe_stmicro, },
  #endif
  };
  #define IDCODE_LEN (IDCODE_CONT_LEN + IDCODE_PART_LEN)
  
  struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs,
  		unsigned int max_hz, unsigned int spi_mode)
  {
  	struct spi_slave *spi;
  	struct spi_flash *flash = NULL;
  	int ret, i, shift;
  	u8 idcode[IDCODE_LEN], *idp;
  
  	spi = spi_setup_slave(bus, cs, max_hz, spi_mode);
  	if (!spi) {
  		printk(BIOS_WARNING, "SF: Failed to set up slave\n");
  		return NULL;
  	}
  
  	spi->rw = SPI_READ_FLAG;
  	ret = spi_claim_bus(spi);
  	if (ret) {
  		printk(BIOS_WARNING, "SF: Failed to claim SPI bus: %d\n", ret);
  		goto err_claim_bus;
  	}
  
  	/* Read the ID codes */
  	ret = spi_flash_cmd(spi, CMD_READ_ID, idcode, sizeof(idcode));
  	if (ret)
  		goto err_read_id;
  
  #if CONFIG_DEBUG_SPI_FLASH
  	printk(BIOS_SPEW, "SF: Got idcodes\n");
  #endif
  
  	/* count the number of continuation bytes */
  	for (shift = 0, idp = idcode;
  	     shift < IDCODE_CONT_LEN && *idp == 0x7f;
  	     ++shift, ++idp)
  		continue;
  
  	/* search the table for matches in shift and id */
  	for (i = 0; i < ARRAY_SIZE(flashes); ++i)
  		if (flashes[i].shift == shift && flashes[i].idcode == *idp) {
  #if CONFIG_SMM_TSEG && defined(__SMM__)
  			/* Need to relocate this function */
  			tseg_relocate((void **)&flashes[i].probe);
  #endif
  			/* we have a match, call probe */
  			flash = flashes[i].probe(spi, idp);
  			if (flash)
  				break;
  		}
  
  	if (!flash) {
  		printk(BIOS_WARNING, "SF: Unsupported manufacturer %02x\n", *idp);
  		goto err_manufacturer_probe;
  	}
  
  #if CONFIG_SMM_TSEG && defined(__SMM__)
  	/* Ensure flash handlers are valid for TSEG */
  	tseg_relocate((void **)&flash->read);
  	tseg_relocate((void **)&flash->write);
  	tseg_relocate((void **)&flash->erase);
  	tseg_relocate((void **)&flash->name);
  #endif
  
  	printk(BIOS_INFO, "SF: Detected %s with page size %x, total %x\n",
  			flash->name, flash->sector_size, flash->size);
  
  	spi_release_bus(spi);
  
  	return flash;
  
  err_manufacturer_probe:
  err_read_id:
  	spi_release_bus(spi);
  err_claim_bus:
  	return NULL;
  }
  