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67f43086 SG |
1 | /* |
2 | * Copyright 2010 Freescale Semiconductor, Inc. All Rights Reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | */ | |
14 | ||
15 | #include <linux/delay.h> | |
16 | #include <linux/err.h> | |
17 | #include <linux/mutex.h> | |
18 | ||
ad377c63 WS |
19 | #include <asm/processor.h> /* for cpu_relax() */ |
20 | ||
67f43086 SG |
21 | #include <mach/mxs.h> |
22 | ||
23 | #define OCOTP_WORD_OFFSET 0x20 | |
24 | #define OCOTP_WORD_COUNT 0x20 | |
25 | ||
26 | #define BM_OCOTP_CTRL_BUSY (1 << 8) | |
27 | #define BM_OCOTP_CTRL_ERROR (1 << 9) | |
28 | #define BM_OCOTP_CTRL_RD_BANK_OPEN (1 << 12) | |
29 | ||
30 | static DEFINE_MUTEX(ocotp_mutex); | |
31 | static u32 ocotp_words[OCOTP_WORD_COUNT]; | |
32 | ||
33 | const u32 *mxs_get_ocotp(void) | |
34 | { | |
35 | void __iomem *ocotp_base = MXS_IO_ADDRESS(MXS_OCOTP_BASE_ADDR); | |
36 | int timeout = 0x400; | |
37 | size_t i; | |
38 | static int once = 0; | |
39 | ||
40 | if (once) | |
41 | return ocotp_words; | |
42 | ||
43 | mutex_lock(&ocotp_mutex); | |
44 | ||
45 | /* | |
46 | * clk_enable(hbus_clk) for ocotp can be skipped | |
47 | * as it must be on when system is running. | |
48 | */ | |
49 | ||
50 | /* try to clear ERROR bit */ | |
51 | __mxs_clrl(BM_OCOTP_CTRL_ERROR, ocotp_base); | |
52 | ||
53 | /* check both BUSY and ERROR cleared */ | |
54 | while ((__raw_readl(ocotp_base) & | |
55 | (BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR)) && --timeout) | |
56 | cpu_relax(); | |
57 | ||
58 | if (unlikely(!timeout)) | |
59 | goto error_unlock; | |
60 | ||
61 | /* open OCOTP banks for read */ | |
62 | __mxs_setl(BM_OCOTP_CTRL_RD_BANK_OPEN, ocotp_base); | |
63 | ||
64 | /* approximately wait 32 hclk cycles */ | |
65 | udelay(1); | |
66 | ||
67 | /* poll BUSY bit becoming cleared */ | |
68 | timeout = 0x400; | |
69 | while ((__raw_readl(ocotp_base) & BM_OCOTP_CTRL_BUSY) && --timeout) | |
70 | cpu_relax(); | |
71 | ||
72 | if (unlikely(!timeout)) | |
73 | goto error_unlock; | |
74 | ||
75 | for (i = 0; i < OCOTP_WORD_COUNT; i++) | |
76 | ocotp_words[i] = __raw_readl(ocotp_base + OCOTP_WORD_OFFSET + | |
77 | i * 0x10); | |
78 | ||
79 | /* close banks for power saving */ | |
80 | __mxs_clrl(BM_OCOTP_CTRL_RD_BANK_OPEN, ocotp_base); | |
81 | ||
82 | once = 1; | |
83 | ||
84 | mutex_unlock(&ocotp_mutex); | |
85 | ||
86 | return ocotp_words; | |
87 | ||
88 | error_unlock: | |
89 | mutex_unlock(&ocotp_mutex); | |
90 | pr_err("%s: timeout in reading OCOTP\n", __func__); | |
91 | return NULL; | |
92 | } |