| Shawn Guo | 67f4308 | 2011-01-14 23:11:23 +0800 | [diff] [blame] | 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 | |
| 19 | #include <mach/mxs.h> |
| 20 | |
| 21 | #define OCOTP_WORD_OFFSET 0x20 |
| 22 | #define OCOTP_WORD_COUNT 0x20 |
| 23 | |
| 24 | #define BM_OCOTP_CTRL_BUSY (1 << 8) |
| 25 | #define BM_OCOTP_CTRL_ERROR (1 << 9) |
| 26 | #define BM_OCOTP_CTRL_RD_BANK_OPEN (1 << 12) |
| 27 | |
| 28 | static DEFINE_MUTEX(ocotp_mutex); |
| 29 | static u32 ocotp_words[OCOTP_WORD_COUNT]; |
| 30 | |
| 31 | const u32 *mxs_get_ocotp(void) |
| 32 | { |
| 33 | void __iomem *ocotp_base = MXS_IO_ADDRESS(MXS_OCOTP_BASE_ADDR); |
| 34 | int timeout = 0x400; |
| 35 | size_t i; |
| 36 | static int once = 0; |
| 37 | |
| 38 | if (once) |
| 39 | return ocotp_words; |
| 40 | |
| 41 | mutex_lock(&ocotp_mutex); |
| 42 | |
| 43 | /* |
| 44 | * clk_enable(hbus_clk) for ocotp can be skipped |
| 45 | * as it must be on when system is running. |
| 46 | */ |
| 47 | |
| 48 | /* try to clear ERROR bit */ |
| 49 | __mxs_clrl(BM_OCOTP_CTRL_ERROR, ocotp_base); |
| 50 | |
| 51 | /* check both BUSY and ERROR cleared */ |
| 52 | while ((__raw_readl(ocotp_base) & |
| 53 | (BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR)) && --timeout) |
| 54 | cpu_relax(); |
| 55 | |
| 56 | if (unlikely(!timeout)) |
| 57 | goto error_unlock; |
| 58 | |
| 59 | /* open OCOTP banks for read */ |
| 60 | __mxs_setl(BM_OCOTP_CTRL_RD_BANK_OPEN, ocotp_base); |
| 61 | |
| 62 | /* approximately wait 32 hclk cycles */ |
| 63 | udelay(1); |
| 64 | |
| 65 | /* poll BUSY bit becoming cleared */ |
| 66 | timeout = 0x400; |
| 67 | while ((__raw_readl(ocotp_base) & BM_OCOTP_CTRL_BUSY) && --timeout) |
| 68 | cpu_relax(); |
| 69 | |
| 70 | if (unlikely(!timeout)) |
| 71 | goto error_unlock; |
| 72 | |
| 73 | for (i = 0; i < OCOTP_WORD_COUNT; i++) |
| 74 | ocotp_words[i] = __raw_readl(ocotp_base + OCOTP_WORD_OFFSET + |
| 75 | i * 0x10); |
| 76 | |
| 77 | /* close banks for power saving */ |
| 78 | __mxs_clrl(BM_OCOTP_CTRL_RD_BANK_OPEN, ocotp_base); |
| 79 | |
| 80 | once = 1; |
| 81 | |
| 82 | mutex_unlock(&ocotp_mutex); |
| 83 | |
| 84 | return ocotp_words; |
| 85 | |
| 86 | error_unlock: |
| 87 | mutex_unlock(&ocotp_mutex); |
| 88 | pr_err("%s: timeout in reading OCOTP\n", __func__); |
| 89 | return NULL; |
| 90 | } |