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  • /*
     * 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 to 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>
    
    #ifdef CONFIG_CMD_OTP
    
    #include <asm/blackfin.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")
    
    int do_otp(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
    {
    	bool force = false;
    	if (!strcmp(argv[1], "--force")) {
    		force = true;
    		argv[1] = argv[0];
    		argv++;
    		--argc;
    	}
    
    	uint32_t (*otp_func)(uint32_t page, uint32_t flags, uint64_t *page_content);
    	if (!strcmp(argv[1], "read"))
    		otp_func = otp_read;
    	else if (!strcmp(argv[1], "write"))
    		otp_func = otp_write;
    	else {
     usage:
    		printf("Usage:\n%s\n", cmdtp->usage);
    		return 1;
    	}
    
    	uint64_t *addr = (uint64_t *)simple_strtoul(argv[2], NULL, 16);
    	uint32_t page = simple_strtoul(argv[3], NULL, 16);
    	uint32_t flags, ret;
    	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'\n");
    			goto usage;
    		}
    	} else
    		half = 0;
    
    	/* do to the nature of OTP, make sure users are sure */
    	if (!force && otp_func == otp_write) {
    		printf(
    			"Writing one time programmable memory\n"
    			"Make sure your operating voltages and temperature are within spec\n"
    			"   source address:  0x%p\n"
    			"   OTP destination: %s page 0x%03X - %s page 0x%03X\n"
    			"   number to write: %ld halfpages\n"
    			" 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\n");
    					return 1;
    				} else if (!exp_ans[i]) {
    					puts("\n");
    					break;
    				}
    			}
    		}
    
    		/* Only supported in newer silicon ... enable writing */
    #if (0)
    		otp_command(OTP_INIT, ...);
    #else
    		*pOTP_TIMING = 0x32149485;
    #endif
    	}
    
    	printf("OTP memory %s: addr 0x%08lx  page 0x%03X  count %ld ... ",
    		argv[1], addr, page, count);
    
    	ret = 0;
    	for (i = half; i < count + half; ++i) {
    		flags = (i % 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF;
    		ret = otp_func(page, flags, addr);
    		if (ret & 0x1)
    			break;
    		else if (ret)
    			puts("W");
    		else
    			puts(".");
    		++addr;
    		if (i % 2)
    			++page;
    	}
    	if (ret & 0x1)
    		printf("\nERROR at page 0x%03X (%s-halfpage): 0x%03X: %s\n",
    			page, lowup(i), ret, otp_strerror(ret));
    	else
    		puts(" done\n");
    
    	if (otp_func == otp_write)
    		/* Only supported in newer silicon ... disable writing */
    #if (0)
    		otp_command(OTP_INIT, ...);
    #else
    		*pOTP_TIMING = 0x1485;
    #endif
    
    	return ret;
    }
    
    U_BOOT_CMD(otp, 6, 0, do_otp,
    	"otp - One-Time-Programmable sub-system\n",
    	"read <addr> <page> [count] [half]\n"
    	"otp write [--force] <addr> <page> [count] [half]\n"
    	"    - read/write 'count' half-pages starting at page 'page' (offset 'half')\n");
    
    #endif