1 files changed, 76 insertions, 0 deletions
diff --git a/arch/arm/mach-mxs/mach-mxs.c b/arch/arm/mach-mxs/mach-mxs.c
index 069049200eb4..f346c432cda2 100644
--- a/arch/arm/mach-mxs/mach-mxs.c
+++ b/arch/arm/mach-mxs/mach-mxs.c
@@ -183,6 +183,82 @@ static void __init imx28_timer_init(void)
 	clocksource_of_init();
 }
 
+#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];
+
+static const u32 *mxs_get_ocotp(void)
+{
+	struct device_node *np;
+	void __iomem *ocotp_base;
+	int timeout = 0x400;
+	size_t i;
+	static int once;
+
+	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;
+}
+
 enum mac_oui {
 	OUI_FSL,
 	OUI_DENX,