drivers/misc/mxc_ocotp.c

   1 /*
   2  * (C) Copyright 2013 ADVANSEE
   3  * Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
   4  *
   5  * Based on Dirk Behme's
   6  * https://github.com/dirkbehme/u-boot-imx6/blob/28b17e9/drivers/misc/imx_otp.c,
   7  * which is based on Freescale's
   8  * http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/tree/drivers/misc/imx_otp.c?h=imx_v2009.08_1.1.0&id=9aa74e6,
   9  * which is:
  10  * Copyright (C) 2011 Freescale Semiconductor, Inc.
  11  *
  12  * SPDX-License-Identifier:     GPL-2.0+
  13  */
  14
  15 #include <common.h>
  16 #include <fuse.h>
  17 #include <asm/errno.h>
  18 #include <asm/io.h>
  19 #include <asm/arch/clock.h>
  20 #include <asm/arch/imx-regs.h>
  21
  22 #define BO_CTRL_WR_UNLOCK               16
  23 #define BM_CTRL_WR_UNLOCK               0xffff0000
  24 #define BV_CTRL_WR_UNLOCK_KEY           0x3e77
  25 #define BM_CTRL_ERROR                   0x00000200
  26 #define BM_CTRL_BUSY                    0x00000100
  27 #define BO_CTRL_ADDR                    0
  28 #define BM_CTRL_ADDR                    0x0000007f
  29
  30 #define BO_TIMING_STROBE_READ           16
  31 #define BM_TIMING_STROBE_READ           0x003f0000
  32 #define BV_TIMING_STROBE_READ_NS        37
  33 #define BO_TIMING_RELAX                 12
  34 #define BM_TIMING_RELAX                 0x0000f000
  35 #define BV_TIMING_RELAX_NS              17
  36 #define BO_TIMING_STROBE_PROG           0
  37 #define BM_TIMING_STROBE_PROG           0x00000fff
  38 #define BV_TIMING_STROBE_PROG_US        10
  39
  40 #define BM_READ_CTRL_READ_FUSE          0x00000001
  41
  42 #define BF(value, field)                (((value) << BO_##field) & BM_##field)
  43
  44 #define WRITE_POSTAMBLE_US              2
  45
  46 static void wait_busy(struct ocotp_regs *regs, unsigned int delay_us)
  47 {
  48         while (readl(&regs->ctrl) & BM_CTRL_BUSY)
  49                 udelay(delay_us);
  50 }
  51
  52 static void clear_error(struct ocotp_regs *regs)
  53 {
  54         writel(BM_CTRL_ERROR, &regs->ctrl_clr);
  55 }
  56
  57 static int prepare_access(struct ocotp_regs **regs, u32 bank, u32 word,
  58                                 int assert, const char *caller)
  59 {
  60         *regs = (struct ocotp_regs *)OCOTP_BASE_ADDR;
  61
  62         if (bank >= ARRAY_SIZE((*regs)->bank) ||
  63                         word >= ARRAY_SIZE((*regs)->bank[0].fuse_regs) >> 2 ||
  64                         !assert) {
  65                 printf("mxc_ocotp %s(): Invalid argument\n", caller);
  66                 return -EINVAL;
  67         }
  68
  69         enable_ocotp_clk(1);
  70
  71         wait_busy(*regs, 1);
  72         clear_error(*regs);
  73
  74         return 0;
  75 }
  76
  77 static int finish_access(struct ocotp_regs *regs, const char *caller)
  78 {
  79         u32 err;
  80
  81         err = !!(readl(&regs->ctrl) & BM_CTRL_ERROR);
  82         clear_error(regs);
  83
  84         if (err) {
  85                 printf("mxc_ocotp %s(): Access protect error\n", caller);
  86                 return -EIO;
  87         }
  88
  89         return 0;
  90 }
  91
  92 static int prepare_read(struct ocotp_regs **regs, u32 bank, u32 word, u32 *val,
  93                         const char *caller)
  94 {
  95         return prepare_access(regs, bank, word, val != NULL, caller);
  96 }
  97
  98 int fuse_read(u32 bank, u32 word, u32 *val)
  99 {
 100         struct ocotp_regs *regs;
 101         int ret;
 102
 103         ret = prepare_read(&regs, bank, word, val, __func__);
 104         if (ret)
 105                 return ret;
 106
 107         *val = readl(&regs->bank[bank].fuse_regs[word << 2]);
 108
 109         return finish_access(regs, __func__);
 110 }
 111
 112 static void set_timing(struct ocotp_regs *regs)
 113 {
 114         u32 ipg_clk;
 115         u32 relax, strobe_read, strobe_prog;
 116         u32 timing;
 117
 118         ipg_clk = mxc_get_clock(MXC_IPG_CLK);
 119
 120         relax = DIV_ROUND_UP(ipg_clk * BV_TIMING_RELAX_NS, 1000000000) - 1;
 121         strobe_read = DIV_ROUND_UP(ipg_clk * BV_TIMING_STROBE_READ_NS,
 122                                         1000000000) + 2 * (relax + 1) - 1;
 123         strobe_prog = DIV_ROUND_CLOSEST(ipg_clk * BV_TIMING_STROBE_PROG_US,
 124                                                 1000000) + 2 * (relax + 1) - 1;
 125
 126         timing = BF(strobe_read, TIMING_STROBE_READ) |
 127                         BF(relax, TIMING_RELAX) |
 128                         BF(strobe_prog, TIMING_STROBE_PROG);
 129
 130         clrsetbits_le32(&regs->timing, BM_TIMING_STROBE_READ | BM_TIMING_RELAX |
 131                         BM_TIMING_STROBE_PROG, timing);
 132 }
 133
 134 static void setup_direct_access(struct ocotp_regs *regs, u32 bank, u32 word,
 135                                 int write)
 136 {
 137         u32 wr_unlock = write ? BV_CTRL_WR_UNLOCK_KEY : 0;
 138         u32 addr = bank << 3 | word;
 139
 140         set_timing(regs);
 141         clrsetbits_le32(&regs->ctrl, BM_CTRL_WR_UNLOCK | BM_CTRL_ADDR,
 142                         BF(wr_unlock, CTRL_WR_UNLOCK) |
 143                         BF(addr, CTRL_ADDR));
 144 }
 145
 146 int fuse_sense(u32 bank, u32 word, u32 *val)
 147 {
 148         struct ocotp_regs *regs;
 149         int ret;
 150
 151         ret = prepare_read(&regs, bank, word, val, __func__);
 152         if (ret)
 153                 return ret;
 154
 155         setup_direct_access(regs, bank, word, false);
 156         writel(BM_READ_CTRL_READ_FUSE, &regs->read_ctrl);
 157         wait_busy(regs, 1);
 158         *val = readl(&regs->read_fuse_data);
 159
 160         return finish_access(regs, __func__);
 161 }
 162
 163 static int prepare_write(struct ocotp_regs **regs, u32 bank, u32 word,
 164                                 const char *caller)
 165 {
 166         return prepare_access(regs, bank, word, true, caller);
 167 }
 168
 169 int fuse_prog(u32 bank, u32 word, u32 val)
 170 {
 171         struct ocotp_regs *regs;
 172         int ret;
 173
 174         ret = prepare_write(&regs, bank, word, __func__);
 175         if (ret)
 176                 return ret;
 177
 178         setup_direct_access(regs, bank, word, true);
 179         writel(val, &regs->data);
 180         wait_busy(regs, BV_TIMING_STROBE_PROG_US);
 181         udelay(WRITE_POSTAMBLE_US);
 182
 183         return finish_access(regs, __func__);
 184 }
 185
 186 int fuse_override(u32 bank, u32 word, u32 val)
 187 {
 188         struct ocotp_regs *regs;
 189         int ret;
 190
 191         ret = prepare_write(&regs, bank, word, __func__);
 192         if (ret)
 193                 return ret;
 194
 195         writel(val, &regs->bank[bank].fuse_regs[word << 2]);
 196
 197         return finish_access(regs, __func__);
 198 }