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(®s->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, ®s->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(®s->ctrl) & BM_CTRL_ERROR); 82 clear_error(regs); 83 84 enable_ocotp_clk(0); 85 86 if (err) { 87 printf("mxc_ocotp %s(): Access protect error\n", caller); 88 return -EIO; 89 } 90 91 return 0; 92 } 93 94 static int prepare_read(struct ocotp_regs **regs, u32 bank, u32 word, u32 *val, 95 const char *caller) 96 { 97 return prepare_access(regs, bank, word, val != NULL, caller); 98 } 99 100 int fuse_read(u32 bank, u32 word, u32 *val) 101 { 102 struct ocotp_regs *regs; 103 int ret; 104 105 ret = prepare_read(®s, bank, word, val, __func__); 106 if (ret) 107 return ret; 108 109 *val = readl(®s->bank[bank].fuse_regs[word << 2]); 110 111 return finish_access(regs, __func__); 112 } 113 114 static void set_timing(struct ocotp_regs *regs) 115 { 116 u32 ipg_clk; 117 u32 relax, strobe_read, strobe_prog; 118 u32 timing; 119 120 ipg_clk = mxc_get_clock(MXC_IPG_CLK); 121 122 relax = DIV_ROUND_UP(ipg_clk * BV_TIMING_RELAX_NS, 1000000000) - 1; 123 strobe_read = DIV_ROUND_UP(ipg_clk * BV_TIMING_STROBE_READ_NS, 124 1000000000) + 2 * (relax + 1) - 1; 125 strobe_prog = DIV_ROUND_CLOSEST(ipg_clk * BV_TIMING_STROBE_PROG_US, 126 1000000) + 2 * (relax + 1) - 1; 127 128 timing = BF(strobe_read, TIMING_STROBE_READ) | 129 BF(relax, TIMING_RELAX) | 130 BF(strobe_prog, TIMING_STROBE_PROG); 131 132 clrsetbits_le32(®s->timing, BM_TIMING_STROBE_READ | BM_TIMING_RELAX | 133 BM_TIMING_STROBE_PROG, timing); 134 } 135 136 static void setup_direct_access(struct ocotp_regs *regs, u32 bank, u32 word, 137 int write) 138 { 139 u32 wr_unlock = write ? BV_CTRL_WR_UNLOCK_KEY : 0; 140 u32 addr = bank << 3 | word; 141 142 set_timing(regs); 143 clrsetbits_le32(®s->ctrl, BM_CTRL_WR_UNLOCK | BM_CTRL_ADDR, 144 BF(wr_unlock, CTRL_WR_UNLOCK) | 145 BF(addr, CTRL_ADDR)); 146 } 147 148 int fuse_sense(u32 bank, u32 word, u32 *val) 149 { 150 struct ocotp_regs *regs; 151 int ret; 152 153 ret = prepare_read(®s, bank, word, val, __func__); 154 if (ret) 155 return ret; 156 157 setup_direct_access(regs, bank, word, false); 158 writel(BM_READ_CTRL_READ_FUSE, ®s->read_ctrl); 159 wait_busy(regs, 1); 160 *val = readl(®s->read_fuse_data); 161 162 return finish_access(regs, __func__); 163 } 164 165 static int prepare_write(struct ocotp_regs **regs, u32 bank, u32 word, 166 const char *caller) 167 { 168 return prepare_access(regs, bank, word, true, caller); 169 } 170 171 int fuse_prog(u32 bank, u32 word, u32 val) 172 { 173 struct ocotp_regs *regs; 174 int ret; 175 176 ret = prepare_write(®s, bank, word, __func__); 177 if (ret) 178 return ret; 179 180 setup_direct_access(regs, bank, word, true); 181 writel(val, ®s->data); 182 wait_busy(regs, BV_TIMING_STROBE_PROG_US); 183 udelay(WRITE_POSTAMBLE_US); 184 185 return finish_access(regs, __func__); 186 } 187 188 int fuse_override(u32 bank, u32 word, u32 val) 189 { 190 struct ocotp_regs *regs; 191 int ret; 192 193 ret = prepare_write(®s, bank, word, __func__); 194 if (ret) 195 return ret; 196 197 writel(val, ®s->bank[bank].fuse_regs[word << 2]); 198 199 return finish_access(regs, __func__); 200 } 201