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Marek Vasut2bbcccf2014-03-06 01:52:03 +01001/*
2 * Freescale i.MX28 OCOTP Driver
3 *
4 * Copyright (C) 2014 Marek Vasut <marex@denx.de>
5 *
6 * SPDX-License-Identifier: GPL-2.0+
7 *
8 * Note: The i.MX23/i.MX28 OCOTP block is a predecessor to the OCOTP block
9 * used in i.MX6 . While these blocks are very similar at the first
10 * glance, by digging deeper, one will notice differences (like the
11 * tight dependence on MXS power block, some completely new registers
12 * etc.) which would make common driver an ifdef nightmare :-(
13 */
14
15#include <common.h>
16#include <fuse.h>
Masahiro Yamada1221ce42016-09-21 11:28:55 +090017#include <linux/errno.h>
Marek Vasut2bbcccf2014-03-06 01:52:03 +010018#include <asm/io.h>
19#include <asm/arch/clock.h>
20#include <asm/arch/imx-regs.h>
21#include <asm/arch/sys_proto.h>
22
23#define MXS_OCOTP_TIMEOUT 100000
24
25static struct mxs_ocotp_regs *ocotp_regs =
26 (struct mxs_ocotp_regs *)MXS_OCOTP_BASE;
27static struct mxs_power_regs *power_regs =
28 (struct mxs_power_regs *)MXS_POWER_BASE;
29static struct mxs_clkctrl_regs *clkctrl_regs =
30 (struct mxs_clkctrl_regs *)MXS_CLKCTRL_BASE;
31
32static int mxs_ocotp_wait_busy_clear(void)
33{
34 uint32_t reg;
35 int timeout = MXS_OCOTP_TIMEOUT;
36
37 while (--timeout) {
38 reg = readl(&ocotp_regs->hw_ocotp_ctrl);
39 if (!(reg & OCOTP_CTRL_BUSY))
40 break;
41 udelay(10);
42 }
43
44 if (!timeout)
45 return -EINVAL;
46
47 /* Wait a little as per FSL datasheet's 'write postamble' section. */
48 udelay(10);
49
50 return 0;
51}
52
53static void mxs_ocotp_clear_error(void)
54{
55 writel(OCOTP_CTRL_ERROR, &ocotp_regs->hw_ocotp_ctrl_clr);
56}
57
58static int mxs_ocotp_read_bank_open(bool open)
59{
60 int ret = 0;
61
62 if (open) {
63 writel(OCOTP_CTRL_RD_BANK_OPEN,
64 &ocotp_regs->hw_ocotp_ctrl_set);
65
66 /*
67 * Wait before polling the BUSY bit, since the BUSY bit might
68 * be asserted only after a few HCLK cycles and if we were to
69 * poll immediatelly, we could miss the busy bit.
70 */
71 udelay(10);
72 ret = mxs_ocotp_wait_busy_clear();
73 } else {
74 writel(OCOTP_CTRL_RD_BANK_OPEN,
75 &ocotp_regs->hw_ocotp_ctrl_clr);
76 }
77
78 return ret;
79}
80
81static void mxs_ocotp_scale_vddio(bool enter, uint32_t *val)
82{
83 uint32_t scale_val;
84
85 if (enter) {
86 /*
87 * Enter the fuse programming VDDIO voltage setup. We start
88 * scaling the voltage from it's current value down to 2.8V
89 * which is the one and only correct voltage for programming
90 * the OCOTP fuses (according to datasheet).
91 */
92 scale_val = readl(&power_regs->hw_power_vddioctrl);
93 scale_val &= POWER_VDDIOCTRL_TRG_MASK;
94
95 /* Return the original voltage. */
96 *val = scale_val;
97
98 /*
99 * Start scaling VDDIO down to 0x2, which is 2.8V . Actually,
100 * the value 0x0 should be 2.8V, but that's not the case on
101 * most designs due to load etc., so we play safe. Undervolt
102 * can actually cause incorrect programming of the fuses and
103 * or reboots of the board.
104 */
105 while (scale_val > 2) {
106 clrsetbits_le32(&power_regs->hw_power_vddioctrl,
107 POWER_VDDIOCTRL_TRG_MASK, --scale_val);
108 udelay(500);
109 }
110 } else {
111 /* Start scaling VDDIO up to original value . */
112 for (scale_val = 2; scale_val <= *val; scale_val++) {
113 clrsetbits_le32(&power_regs->hw_power_vddioctrl,
114 POWER_VDDIOCTRL_TRG_MASK, scale_val);
115 udelay(500);
116 }
117 }
118
119 mdelay(10);
120}
121
122static int mxs_ocotp_wait_hclk_ready(void)
123{
124 uint32_t reg, timeout = MXS_OCOTP_TIMEOUT;
125
126 while (--timeout) {
127 reg = readl(&clkctrl_regs->hw_clkctrl_hbus);
128 if (!(reg & CLKCTRL_HBUS_ASM_BUSY))
129 break;
130 }
131
132 if (!timeout)
133 return -EINVAL;
134
135 return 0;
136}
137
138static int mxs_ocotp_scale_hclk(bool enter, uint32_t *val)
139{
140 uint32_t scale_val;
141 int ret;
142
143 ret = mxs_ocotp_wait_hclk_ready();
144 if (ret)
145 return ret;
146
147 /* Set CPU bypass */
148 writel(CLKCTRL_CLKSEQ_BYPASS_CPU,
149 &clkctrl_regs->hw_clkctrl_clkseq_set);
150
151 if (enter) {
152 /* Return the original HCLK clock speed. */
153 *val = readl(&clkctrl_regs->hw_clkctrl_hbus);
154 *val &= CLKCTRL_HBUS_DIV_MASK;
Chris Smithd4b8b5d2015-07-12 15:00:11 +0200155 *val >>= CLKCTRL_HBUS_DIV_OFFSET;
Marek Vasut2bbcccf2014-03-06 01:52:03 +0100156
157 /* Scale the HCLK to 454/19 = 23.9 MHz . */
158 scale_val = (~19) << CLKCTRL_HBUS_DIV_OFFSET;
159 scale_val &= CLKCTRL_HBUS_DIV_MASK;
160 } else {
161 /* Scale the HCLK back to original frequency. */
162 scale_val = (~(*val)) << CLKCTRL_HBUS_DIV_OFFSET;
163 scale_val &= CLKCTRL_HBUS_DIV_MASK;
164 }
165
166 writel(CLKCTRL_HBUS_DIV_MASK,
167 &clkctrl_regs->hw_clkctrl_hbus_set);
168 writel(scale_val,
169 &clkctrl_regs->hw_clkctrl_hbus_clr);
170
171 mdelay(10);
172
173 ret = mxs_ocotp_wait_hclk_ready();
174 if (ret)
175 return ret;
176
177 /* Disable CPU bypass */
178 writel(CLKCTRL_CLKSEQ_BYPASS_CPU,
179 &clkctrl_regs->hw_clkctrl_clkseq_clr);
180
181 mdelay(10);
182
183 return 0;
184}
185
186static int mxs_ocotp_write_fuse(uint32_t addr, uint32_t mask)
187{
188 uint32_t hclk_val, vddio_val;
189 int ret;
190
Hector Palacios3d99fcb2014-11-21 17:54:44 +0100191 mxs_ocotp_clear_error();
192
Marek Vasut2bbcccf2014-03-06 01:52:03 +0100193 /* Make sure the banks are closed for reading. */
194 ret = mxs_ocotp_read_bank_open(0);
195 if (ret) {
196 puts("Failed closing banks for reading!\n");
197 return ret;
198 }
199
200 ret = mxs_ocotp_scale_hclk(1, &hclk_val);
201 if (ret) {
202 puts("Failed scaling down the HCLK!\n");
203 return ret;
204 }
205 mxs_ocotp_scale_vddio(1, &vddio_val);
206
207 ret = mxs_ocotp_wait_busy_clear();
208 if (ret) {
209 puts("Failed waiting for ready state!\n");
210 goto fail;
211 }
212
213 /* Program the fuse address */
214 writel(addr | OCOTP_CTRL_WR_UNLOCK_KEY, &ocotp_regs->hw_ocotp_ctrl);
215
216 /* Program the data. */
217 writel(mask, &ocotp_regs->hw_ocotp_data);
218
219 udelay(10);
220
221 ret = mxs_ocotp_wait_busy_clear();
222 if (ret) {
223 puts("Failed waiting for ready state!\n");
224 goto fail;
225 }
226
Hector Palaciosad5dd7a2014-11-21 17:54:43 +0100227 /* Check for errors */
228 if (readl(&ocotp_regs->hw_ocotp_ctrl) & OCOTP_CTRL_ERROR) {
229 puts("Failed writing fuses!\n");
230 ret = -EPERM;
231 goto fail;
232 }
233
Marek Vasut2bbcccf2014-03-06 01:52:03 +0100234fail:
235 mxs_ocotp_scale_vddio(0, &vddio_val);
Hector Palaciosd8d160e2014-11-21 17:54:42 +0100236 if (mxs_ocotp_scale_hclk(0, &hclk_val))
Marek Vasut2bbcccf2014-03-06 01:52:03 +0100237 puts("Failed scaling up the HCLK!\n");
Marek Vasut2bbcccf2014-03-06 01:52:03 +0100238
239 return ret;
240}
241
242static int mxs_ocotp_read_fuse(uint32_t reg, uint32_t *val)
243{
244 int ret;
245
246 /* Register offset from CUST0 */
247 reg = ((uint32_t)&ocotp_regs->hw_ocotp_cust0) + (reg << 4);
248
249 ret = mxs_ocotp_wait_busy_clear();
250 if (ret) {
251 puts("Failed waiting for ready state!\n");
252 return ret;
253 }
254
255 mxs_ocotp_clear_error();
256
257 ret = mxs_ocotp_read_bank_open(1);
258 if (ret) {
259 puts("Failed opening banks for reading!\n");
260 return ret;
261 }
262
263 *val = readl(reg);
264
265 ret = mxs_ocotp_read_bank_open(0);
266 if (ret) {
267 puts("Failed closing banks for reading!\n");
268 return ret;
269 }
270
271 return ret;
272}
273
274static int mxs_ocotp_valid(u32 bank, u32 word)
275{
276 if (bank > 4)
277 return -EINVAL;
278 if (word > 7)
279 return -EINVAL;
280 return 0;
281}
282
283/*
284 * The 'fuse' command API
285 */
286int fuse_read(u32 bank, u32 word, u32 *val)
287{
288 int ret;
289
290 ret = mxs_ocotp_valid(bank, word);
291 if (ret)
292 return ret;
293
294 return mxs_ocotp_read_fuse((bank << 3) | word, val);
295}
296
297int fuse_prog(u32 bank, u32 word, u32 val)
298{
299 int ret;
300
301 ret = mxs_ocotp_valid(bank, word);
302 if (ret)
303 return ret;
304
305 return mxs_ocotp_write_fuse((bank << 3) | word, val);
306}
307
308int fuse_sense(u32 bank, u32 word, u32 *val)
309{
310 /* We do not support sensing :-( */
311 return -EINVAL;
312}
313
314int fuse_override(u32 bank, u32 word, u32 val)
315{
316 /* We do not support overriding :-( */
317 return -EINVAL;
318}