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/*
* Copyright 2010 Freescale Semiconductor, Inc. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <asm/processor.h> /* for cpu_relax() */
#include <mach/mxs.h>
#include <mach/common.h>
#define OCOTP_WORD_OFFSET 0x20
#define OCOTP_WORD_COUNT 0x20
#define BM_OCOTP_CTRL_BUSY (1 << 8)
#define BM_OCOTP_CTRL_ERROR (1 << 9)
#define BM_OCOTP_CTRL_RD_BANK_OPEN (1 << 12)
static DEFINE_MUTEX(ocotp_mutex);
static u32 ocotp_words[OCOTP_WORD_COUNT];
const u32 *mxs_get_ocotp(void)
{
struct device_node *np;
void __iomem *ocotp_base;
int timeout = 0x400;
size_t i;
static int once = 0;
if (once)
return ocotp_words;
np = of_find_compatible_node(NULL, NULL, "fsl,ocotp");
ocotp_base = of_iomap(np, 0);
WARN_ON(!ocotp_base);
mutex_lock(&ocotp_mutex);
/*
* clk_enable(hbus_clk) for ocotp can be skipped
* as it must be on when system is running.
*/
/* try to clear ERROR bit */
__mxs_clrl(BM_OCOTP_CTRL_ERROR, ocotp_base);
/* check both BUSY and ERROR cleared */
while ((__raw_readl(ocotp_base) &
(BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR)) && --timeout)
cpu_relax();
if (unlikely(!timeout))
goto error_unlock;
/* open OCOTP banks for read */
__mxs_setl(BM_OCOTP_CTRL_RD_BANK_OPEN, ocotp_base);
/* approximately wait 32 hclk cycles */
udelay(1);
/* poll BUSY bit becoming cleared */
timeout = 0x400;
while ((__raw_readl(ocotp_base) & BM_OCOTP_CTRL_BUSY) && --timeout)
cpu_relax();
if (unlikely(!timeout))
goto error_unlock;
for (i = 0; i < OCOTP_WORD_COUNT; i++)
ocotp_words[i] = __raw_readl(ocotp_base + OCOTP_WORD_OFFSET +
i * 0x10);
/* close banks for power saving */
__mxs_clrl(BM_OCOTP_CTRL_RD_BANK_OPEN, ocotp_base);
once = 1;
mutex_unlock(&ocotp_mutex);
return ocotp_words;
error_unlock:
mutex_unlock(&ocotp_mutex);
pr_err("%s: timeout in reading OCOTP\n", __func__);
return NULL;
}
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