Add mxc_ocotp driver

Add an mxc_ocotp driver for i.MX6.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>

1 files changed, 216 insertions, 0 deletions

diff --git a/drivers/misc/mxc_ocotp.c b/drivers/misc/mxc_ocotp.c
new file mode 100644
index 0000000..0095b47
--- /dev/null
+++ b/drivers/misc/mxc_ocotp.c
@@ -0,0 +1,216 @@
+/*
+ * (C) Copyright 2013 ADVANSEE
+ * Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
+ *
+ * Based on Dirk Behme's
+ * https://github.com/dirkbehme/u-boot-imx6/blob/28b17e9/drivers/misc/imx_otp.c,
+ * which is based on Freescale's
+ * http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/tree/drivers/misc/imx_otp.c?h=imx_v2009.08_1.1.0&id=9aa74e6,
+ * which is:
+ * Copyright (C) 2011 Freescale Semiconductor, Inc.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <fuse.h>
+#include <asm/errno.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/imx-regs.h>
+
+#define BO_CTRL_WR_UNLOCK		16
+#define BM_CTRL_WR_UNLOCK		0xffff0000
+#define BV_CTRL_WR_UNLOCK_KEY		0x3e77
+#define BM_CTRL_ERROR			0x00000200
+#define BM_CTRL_BUSY			0x00000100
+#define BO_CTRL_ADDR			0
+#define BM_CTRL_ADDR			0x0000007f
+
+#define BO_TIMING_STROBE_READ		16
+#define BM_TIMING_STROBE_READ		0x003f0000
+#define BV_TIMING_STROBE_READ_NS	37
+#define BO_TIMING_RELAX			12
+#define BM_TIMING_RELAX			0x0000f000
+#define BV_TIMING_RELAX_NS		17
+#define BO_TIMING_STROBE_PROG		0
+#define BM_TIMING_STROBE_PROG		0x00000fff
+#define BV_TIMING_STROBE_PROG_US	10
+
+#define BM_READ_CTRL_READ_FUSE		0x00000001
+
+#define BF(value, field)		(((value) << BO_##field) & BM_##field)
+
+#define WRITE_POSTAMBLE_US		2
+
+static void wait_busy(struct ocotp_regs *regs, unsigned int delay_us)
+{
+	while (readl(&regs->ctrl) & BM_CTRL_BUSY)
+		udelay(delay_us);
+}
+
+static void clear_error(struct ocotp_regs *regs)
+{
+	writel(BM_CTRL_ERROR, &regs->ctrl_clr);
+}
+
+static int prepare_access(struct ocotp_regs **regs, u32 bank, u32 word,
+				int assert, const char *caller)
+{
+	*regs = (struct ocotp_regs *)OCOTP_BASE_ADDR;
+
+	if (bank >= ARRAY_SIZE((*regs)->bank) ||
+			word >= ARRAY_SIZE((*regs)->bank[0].fuse_regs) >> 2 ||
+			!assert) {
+		printf("mxc_ocotp %s(): Invalid argument\n", caller);
+		return -EINVAL;
+	}
+
+	enable_ocotp_clk(1);
+
+	wait_busy(*regs, 1);
+	clear_error(*regs);
+
+	return 0;
+}
+
+static int finish_access(struct ocotp_regs *regs, const char *caller)
+{
+	u32 err;
+
+	err = !!(readl(&regs->ctrl) & BM_CTRL_ERROR);
+	clear_error(regs);
+
+	enable_ocotp_clk(0);
+
+	if (err) {
+		printf("mxc_ocotp %s(): Access protect error\n", caller);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int prepare_read(struct ocotp_regs **regs, u32 bank, u32 word, u32 *val,
+			const char *caller)
+{
+	return prepare_access(regs, bank, word, val != NULL, caller);
+}
+
+int fuse_read(u32 bank, u32 word, u32 *val)
+{
+	struct ocotp_regs *regs;
+	int ret;
+
+	ret = prepare_read(&regs, bank, word, val, __func__);
+	if (ret)
+		return ret;
+
+	*val = readl(&regs->bank[bank].fuse_regs[word << 2]);
+
+	return finish_access(regs, __func__);
+}
+
+static void set_timing(struct ocotp_regs *regs)
+{
+	u32 ipg_clk;
+	u32 relax, strobe_read, strobe_prog;
+	u32 timing;
+
+	ipg_clk = mxc_get_clock(MXC_IPG_CLK);
+
+	relax = DIV_ROUND_UP(ipg_clk * BV_TIMING_RELAX_NS, 1000000000) - 1;
+	strobe_read = DIV_ROUND_UP(ipg_clk * BV_TIMING_STROBE_READ_NS,
+					1000000000) + 2 * (relax + 1) - 1;
+	strobe_prog = DIV_ROUND(ipg_clk * BV_TIMING_STROBE_PROG_US, 1000000) +
+			2 * (relax + 1) - 1;
+
+	timing = BF(strobe_read, TIMING_STROBE_READ) |
+			BF(relax, TIMING_RELAX) |
+			BF(strobe_prog, TIMING_STROBE_PROG);
+
+	clrsetbits_le32(&regs->timing, BM_TIMING_STROBE_READ | BM_TIMING_RELAX |
+			BM_TIMING_STROBE_PROG, timing);
+}
+
+static void setup_direct_access(struct ocotp_regs *regs, u32 bank, u32 word,
+				int write)
+{
+	u32 wr_unlock = write ? BV_CTRL_WR_UNLOCK_KEY : 0;
+	u32 addr = bank << 3 | word;
+
+	set_timing(regs);
+	clrsetbits_le32(&regs->ctrl, BM_CTRL_WR_UNLOCK | BM_CTRL_ADDR,
+			BF(wr_unlock, CTRL_WR_UNLOCK) |
+			BF(addr, CTRL_ADDR));
+}
+
+int fuse_sense(u32 bank, u32 word, u32 *val)
+{
+	struct ocotp_regs *regs;
+	int ret;
+
+	ret = prepare_read(&regs, bank, word, val, __func__);
+	if (ret)
+		return ret;
+
+	setup_direct_access(regs, bank, word, false);
+	writel(BM_READ_CTRL_READ_FUSE, &regs->read_ctrl);
+	wait_busy(regs, 1);
+	*val = readl(&regs->read_fuse_data);
+
+	return finish_access(regs, __func__);
+}
+
+static int prepare_write(struct ocotp_regs **regs, u32 bank, u32 word,
+				const char *caller)
+{
+	return prepare_access(regs, bank, word, true, caller);
+}
+
+int fuse_prog(u32 bank, u32 word, u32 val)
+{
+	struct ocotp_regs *regs;
+	int ret;
+
+	ret = prepare_write(&regs, bank, word, __func__);
+	if (ret)
+		return ret;
+
+	setup_direct_access(regs, bank, word, true);
+	writel(val, &regs->data);
+	wait_busy(regs, BV_TIMING_STROBE_PROG_US);
+	udelay(WRITE_POSTAMBLE_US);
+
+	return finish_access(regs, __func__);
+}
+
+int fuse_override(u32 bank, u32 word, u32 val)
+{
+	struct ocotp_regs *regs;
+	int ret;
+
+	ret = prepare_write(&regs, bank, word, __func__);
+	if (ret)
+		return ret;
+
+	writel(val, &regs->bank[bank].fuse_regs[word << 2]);
+
+	return finish_access(regs, __func__);
+}