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authorShawn Guo <shawn.guo@freescale.com>2011-01-14 23:11:23 +0800
committerSascha Hauer <s.hauer@pengutronix.de>2011-01-21 11:36:49 +0100
commit67f43086a24b77a82724855141a5b7a4d72549bd (patch)
treeb859152193a7ff7f9e568cbab2c835a4b9c5237d /arch/arm/mach-mxs/ocotp.c
parentbb58b3e8b18c542f30f898fff82f7ce58a4bdf7a (diff)
ARM: mxs: add ocotp read function
Signed-off-by: Shawn Guo <shawn.guo@freescale.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'arch/arm/mach-mxs/ocotp.c')
-rw-r--r--arch/arm/mach-mxs/ocotp.c90
1 files changed, 90 insertions, 0 deletions
diff --git a/arch/arm/mach-mxs/ocotp.c b/arch/arm/mach-mxs/ocotp.c
new file mode 100644
index 00000000000..65157a35dbb
--- /dev/null
+++ b/arch/arm/mach-mxs/ocotp.c
@@ -0,0 +1,90 @@
+/*
+ * 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 <mach/mxs.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)
+{
+ void __iomem *ocotp_base = MXS_IO_ADDRESS(MXS_OCOTP_BASE_ADDR);
+ int timeout = 0x400;
+ size_t i;
+ static int once = 0;
+
+ if (once)
+ return ocotp_words;
+
+ 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;
+}