/*
   * cmd_otp.c - interface to Blackfin on-chip One-Time-Programmable memory
   *
   * Copyright (c) 2007-2008 Analog Devices Inc.
   *
   * Licensed under the GPL-2 or later.
   */

  /* There are 512 128-bit "pages" (0x000 through 0x1FF).

   * The pages are accessable as 64-bit "halfpages" (an upper and lower half).
   * The pages are not part of the memory map.  There is an OTP controller which
   * handles scanning in/out of bits.  While access is done through OTP MMRs,
   * the bootrom provides C-callable helper functions to handle the interaction.
   */
  
  #include <config.h>
  #include <common.h>
  #include <command.h>

  #include <asm/blackfin.h>

  #include <asm/clock.h>

  #include <asm/mach-common/bits/otp.h>
  
  static const char *otp_strerror(uint32_t err)
  {
  	switch (err) {
  	case 0:                   return "no error";
  	case OTP_WRITE_ERROR:     return "OTP fuse write error";
  	case OTP_READ_ERROR:      return "OTP fuse read error";
  	case OTP_ACC_VIO_ERROR:   return "invalid OTP address";
  	case OTP_DATA_MULT_ERROR: return "multiple bad bits detected";
  	case OTP_ECC_MULT_ERROR:  return "error in ECC bits";
  	case OTP_PREV_WR_ERROR:   return "space already written";
  	case OTP_DATA_SB_WARN:    return "single bad bit in half page";
  	case OTP_ECC_SB_WARN:     return "single bad bit in ECC";
  	default:                  return "unknown error";
  	}
  }
  
  #define lowup(x) ((x) % 2 ? "upper" : "lower")

  static int check_voltage(void)
  {
  	/* Make sure voltage limits are within datasheet spec */
  	uint16_t vr_ctl = bfin_read_VR_CTL();
  
  #ifdef __ADSPBF54x__
  	/* 0.9V <= VDDINT <= 1.1V */
  	if ((vr_ctl & 0xc) && (vr_ctl & 0xc0) == 0xc0)
  		return 1;
  #else
  	/* for the parts w/out qualification yet */
  	(void)vr_ctl;
  #endif
  
  	return 0;
  }
  
  static void set_otp_timing(bool write)

  {

  	static uint32_t timing;
  	if (!timing) {
  		uint32_t tp1, tp2, tp3;
  		/* OTP_TP1 = 1000 / sclk_period (in nanoseconds)
  		 * OTP_TP1 = 1000 / (1 / get_sclk() * 10^9)
  		 * OTP_TP1 = (1000 * get_sclk()) / 10^9
  		 * OTP_TP1 = get_sclk() / 10^6
  		 */
  		tp1 = get_sclk() / 1000000;
  		/* OTP_TP2 = 400 / (2 * sclk_period)
  		 * OTP_TP2 = 400 / (2 * 1 / get_sclk() * 10^9)
  		 * OTP_TP2 = (400 * get_sclk()) / (2 * 10^9)
  		 * OTP_TP2 = (2 * get_sclk()) / 10^7
  		 */
  		tp2 = (2 * get_sclk() / 10000000) << 8;
  		/* OTP_TP3 = magic constant */
  		tp3 = (0x1401) << 15;
  		timing = tp1 | tp2 | tp3;

  	}

  	bfrom_OtpCommand(OTP_INIT, write ? timing : timing & ~(-1 << 15));
  }

  int do_otp(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])

  {

  	char *cmd;

  	uint32_t ret, base_flags;
  	bool prompt_user, force_read;

  	uint32_t (*otp_func)(uint32_t page, uint32_t flags, uint64_t *page_content);

  
  	if (argc < 4) {

   usage:

  		return CMD_RET_USAGE;

  	}

  	prompt_user = false;
  	base_flags = 0;

  	cmd = argv[1];
  	if (!strcmp(cmd, "read"))

  		otp_func = bfrom_OtpRead;

  	else if (!strcmp(cmd, "dump")) {

  		otp_func = bfrom_OtpRead;
  		force_read = true;

  	} else if (!strcmp(cmd, "write")) {

  		otp_func = bfrom_OtpWrite;
  		base_flags = OTP_CHECK_FOR_PREV_WRITE;
  		if (!strcmp(argv[2], "--force")) {

  			argv++;
  			--argc;
  		} else
  			prompt_user = false;

  	} else if (!strcmp(cmd, "lock")) {

  		if (argc != 4)
  			goto usage;
  		otp_func = bfrom_OtpWrite;
  		base_flags = OTP_LOCK;
  	} else
  		goto usage;

  	uint64_t *addr = (uint64_t *)simple_strtoul(argv[2], NULL, 16);
  	uint32_t page = simple_strtoul(argv[3], NULL, 16);

  	uint32_t flags;

  	size_t i, count;
  	ulong half;
  
  	if (argc > 4)
  		count = simple_strtoul(argv[4], NULL, 16);
  	else
  		count = 2;
  
  	if (argc > 5) {
  		half = simple_strtoul(argv[5], NULL, 16);
  		if (half != 0 && half != 1) {
  			puts("Error: 'half' can only be '0' or '1'
  ");
  			goto usage;
  		}
  	} else
  		half = 0;

  	/* "otp lock" has slightly different semantics */
  	if (base_flags & OTP_LOCK) {
  		count = page;
  		page = (uint32_t)addr;
  		addr = NULL;
  	}

  	/* do to the nature of OTP, make sure users are sure */

  	if (prompt_user) {

  		printf(
  			"Writing one time programmable memory
  "
  			"Make sure your operating voltages and temperature are within spec
  "
  			"   source address:  0x%p
  "

  			"   OTP destination: %s page 0x%03X - %s page 0x%03lX
  "
  			"   number to write: %lu halfpages
  "

  			" type \"YES\" (no quotes) to confirm: ",
  			addr,
  			lowup(half), page,
  			lowup(half + count - 1), page + (half + count - 1) / 2,
  			half + count
  		);
  
  		i = 0;
  		while (1) {
  			if (tstc()) {
  				const char exp_ans[] = "YES\r";
  				char c;
  				putc(c = getc());
  				if (exp_ans[i++] != c) {
  					printf(" Aborting
  ");
  					return 1;
  				} else if (!exp_ans[i]) {
  					puts("
  ");
  					break;
  				}
  			}
  		}

  	}

  	printf("OTP memory %s: addr 0x%p  page 0x%03X  count %zu ... ",

  		cmd, addr, page, count);

  	set_otp_timing(otp_func == bfrom_OtpWrite);
  	if (otp_func == bfrom_OtpWrite && check_voltage()) {
  		puts("ERROR: VDDINT voltage is out of spec for writing
  ");
  		return -1;
  	}
  
  	/* Do the actual reading/writing stuff */

  	ret = 0;
  	for (i = half; i < count + half; ++i) {

  		flags = base_flags | (i % 2 ? OTP_UPPER_HALF : OTP_LOWER_HALF);
   try_again:

  		ret = otp_func(page, flags, addr);

  		if (ret & OTP_MASTER_ERROR) {
  			if (force_read) {
  				if (flags & OTP_NO_ECC)
  					break;
  				else
  					flags |= OTP_NO_ECC;
  				puts("E");
  				goto try_again;
  			} else
  				break;
  		} else if (ret)

  			puts("W");
  		else
  			puts(".");

  		if (!(base_flags & OTP_LOCK)) {
  			++addr;
  			if (i % 2)
  				++page;
  		} else

  			++page;
  	}
  	if (ret & 0x1)
  		printf("
  ERROR at page 0x%03X (%s-halfpage): 0x%03X: %s
  ",
  			page, lowup(i), ret, otp_strerror(ret));
  	else
  		puts(" done
  ");

  	/* Make sure we disable writing */
  	set_otp_timing(false);
  	bfrom_OtpCommand(OTP_CLOSE, 0);

  
  	return ret;
  }

  U_BOOT_CMD(
  	otp, 7, 0, do_otp,

  	"One-Time-Programmable sub-system",

  	"read <addr> <page> [count] [half]
  "

  	" - read 'count' half-pages starting at 'page' (offset 'half') to 'addr'
  "
  	"otp dump <addr> <page> [count] [half]
  "
  	" - like 'otp read', but skip read errors
  "

  	"otp write [--force] <addr> <page> [count] [half]
  "

  	" - write 'count' half-pages starting at 'page' (offset 'half') from 'addr'
  "
  	"otp lock <page> <count>
  "

  	" - lock 'count' pages starting at 'page'"
  );