[U-Boot] [PATCH] ARM: mxs: Add OCOTP driver

Marek Vasut
2014-03-06T00:52:03Z

Add yet another OCOTP driver for this i.MX family. This time, it's a driver for
the OCOTP variant found in the i.MX23 and i.MX28. This version of OCOTP is too
different from the i.MX6 one that I could not use the mxc_ocotp.c driver without
making it into a big pile of #ifdef . This driver implements the regular fuse
command interface, but due to the IP blocks' limitation, we support only READ
and PROG functions.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
---
drivers/misc/Makefile | 1 +
drivers/misc/mxs_ocotp.c | 311 +++++++++++++++++++++++++++++++++++++++++++++++
include/configs/mxs.h | 5 +
3 files changed, 317 insertions(+)
create mode 100644 drivers/misc/mxs_ocotp.c

diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index c77e40a..0f9f6f1 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_FSL_IIM) += fsl_iim.o
obj-$(CONFIG_GPIO_LED) += gpio_led.o
obj-$(CONFIG_FSL_MC9SDZ60) += mc9sdz60.o
obj-$(CONFIG_MXC_OCOTP) += mxc_ocotp.o
+obj-$(CONFIG_MXS_OCOTP) += mxs_ocotp.o
obj-$(CONFIG_NS87308) += ns87308.o
obj-$(CONFIG_PDSP188x) += pdsp188x.o
obj-$(CONFIG_STATUS_LED) += status_led.o
diff --git a/drivers/misc/mxs_ocotp.c b/drivers/misc/mxs_ocotp.c
new file mode 100644
index 0000000..545d3eb
--- /dev/null
+++ b/drivers/misc/mxs_ocotp.c
@@ -0,0 +1,311 @@
+/*
+ * Freescale i.MX28 OCOTP Driver
+ *
+ * Copyright (C) 2014 Marek Vasut <marex@denx.de>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * Note: The i.MX23/i.MX28 OCOTP block is a predecessor to the OCOTP block
+ * used in i.MX6 . While these blocks are very similar at the first
+ * glance, by digging deeper, one will notice differences (like the
+ * tight dependence on MXS power block, some completely new registers
+ * etc.) which would make common driver an ifdef nightmare :-(
+ */
+
+#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>
+#include <asm/arch/sys_proto.h>
+
+#define MXS_OCOTP_TIMEOUT 100000
+
+static struct mxs_ocotp_regs *ocotp_regs =
+ (struct mxs_ocotp_regs *)MXS_OCOTP_BASE;
+static struct mxs_power_regs *power_regs =
+ (struct mxs_power_regs *)MXS_POWER_BASE;
+static struct mxs_clkctrl_regs *clkctrl_regs =
+ (struct mxs_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+static int mxs_ocotp_wait_busy_clear(void)
+{
+ uint32_t reg;
+ int timeout = MXS_OCOTP_TIMEOUT;
+
+ while (--timeout) {
+ reg = readl(&ocotp_regs->hw_ocotp_ctrl);
+ if (!(reg & OCOTP_CTRL_BUSY))
+ break;
+ udelay(10);
+ }
+
+ if (!timeout)
+ return -EINVAL;
+
+ /* Wait a little as per FSL datasheet's 'write postamble' section. */
+ udelay(10);
+
+ return 0;
+}
+
+static void mxs_ocotp_clear_error(void)
+{
+ writel(OCOTP_CTRL_ERROR, &ocotp_regs->hw_ocotp_ctrl_clr);
+}
+
+static int mxs_ocotp_read_bank_open(bool open)
+{
+ int ret = 0;
+
+ if (open) {
+ writel(OCOTP_CTRL_RD_BANK_OPEN,
+ &ocotp_regs->hw_ocotp_ctrl_set);
+
+ /*
+ * Wait before polling the BUSY bit, since the BUSY bit might
+ * be asserted only after a few HCLK cycles and if we were to
+ * poll immediatelly, we could miss the busy bit.
+ */
+ udelay(10);
+ ret = mxs_ocotp_wait_busy_clear();
+ } else {
+ writel(OCOTP_CTRL_RD_BANK_OPEN,
+ &ocotp_regs->hw_ocotp_ctrl_clr);
+ }
+
+ return ret;
+}
+
+static void mxs_ocotp_scale_vddio(bool enter, uint32_t *val)
+{
+ uint32_t scale_val;
+
+ if (enter) {
+ /*
+ * Enter the fuse programming VDDIO voltage setup. We start
+ * scaling the voltage from it's current value down to 2.8V
+ * which is the one and only correct voltage for programming
+ * the OCOTP fuses (according to datasheet).
+ */
+ scale_val = readl(&power_regs->hw_power_vddioctrl);
+ scale_val &= POWER_VDDIOCTRL_TRG_MASK;
+
+ /* Return the original voltage. */
+ *val = scale_val;
+
+ /*
+ * Start scaling VDDIO down to 0x2, which is 2.8V . Actually,
+ * the value 0x0 should be 2.8V, but that's not the case on
+ * most designs due to load etc., so we play safe. Undervolt
+ * can actually cause incorrect programming of the fuses and
+ * or reboots of the board.
+ */
+ while (scale_val > 2) {
+ clrsetbits_le32(&power_regs->hw_power_vddioctrl,
+ POWER_VDDIOCTRL_TRG_MASK, --scale_val);
+ udelay(500);
+ }
+ } else {
+ /* Start scaling VDDIO up to original value . */
+ for (scale_val = 2; scale_val <= *val; scale_val++) {
+ clrsetbits_le32(&power_regs->hw_power_vddioctrl,
+ POWER_VDDIOCTRL_TRG_MASK, scale_val);
+ udelay(500);
+ }
+ }
+
+ mdelay(10);
+}
+
+static int mxs_ocotp_wait_hclk_ready(void)
+{
+ uint32_t reg, timeout = MXS_OCOTP_TIMEOUT;
+
+ while (--timeout) {
+ reg = readl(&clkctrl_regs->hw_clkctrl_hbus);
+ if (!(reg & CLKCTRL_HBUS_ASM_BUSY))
+ break;
+ }
+
+ if (!timeout)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int mxs_ocotp_scale_hclk(bool enter, uint32_t *val)
+{
+ uint32_t scale_val;
+ int ret;
+
+ ret = mxs_ocotp_wait_hclk_ready();
+ if (ret)
+ return ret;
+
+ /* Set CPU bypass */
+ writel(CLKCTRL_CLKSEQ_BYPASS_CPU,
+ &clkctrl_regs->hw_clkctrl_clkseq_set);
+
+ if (enter) {
+ /* Return the original HCLK clock speed. */
+ *val = readl(&clkctrl_regs->hw_clkctrl_hbus);
+ *val &= CLKCTRL_HBUS_DIV_MASK;
+
+ /* Scale the HCLK to 454/19 = 23.9 MHz . */
+ scale_val = (~19) << CLKCTRL_HBUS_DIV_OFFSET;
+ scale_val &= CLKCTRL_HBUS_DIV_MASK;
+ } else {
+ /* Scale the HCLK back to original frequency. */
+ scale_val = (~(*val)) << CLKCTRL_HBUS_DIV_OFFSET;
+ scale_val &= CLKCTRL_HBUS_DIV_MASK;
+ }
+
+ writel(CLKCTRL_HBUS_DIV_MASK,
+ &clkctrl_regs->hw_clkctrl_hbus_set);
+ writel(scale_val,
+ &clkctrl_regs->hw_clkctrl_hbus_clr);
+
+ mdelay(10);
+
+ ret = mxs_ocotp_wait_hclk_ready();
+ if (ret)
+ return ret;
+
+ /* Disable CPU bypass */
+ writel(CLKCTRL_CLKSEQ_BYPASS_CPU,
+ &clkctrl_regs->hw_clkctrl_clkseq_clr);
+
+ mdelay(10);
+
+ return 0;
+}
+
+static int mxs_ocotp_write_fuse(uint32_t addr, uint32_t mask)
+{
+ uint32_t hclk_val, vddio_val;
+ int ret;
+
+ /* Make sure the banks are closed for reading. */
+ ret = mxs_ocotp_read_bank_open(0);
+ if (ret) {
+ puts("Failed closing banks for reading!\n");
+ return ret;
+ }
+
+ ret = mxs_ocotp_scale_hclk(1, &hclk_val);
+ if (ret) {
+ puts("Failed scaling down the HCLK!\n");
+ return ret;
+ }
+ mxs_ocotp_scale_vddio(1, &vddio_val);
+
+ ret = mxs_ocotp_wait_busy_clear();
+ if (ret) {
+ puts("Failed waiting for ready state!\n");
+ goto fail;
+ }
+
+ /* Program the fuse address */
+ writel(addr | OCOTP_CTRL_WR_UNLOCK_KEY, &ocotp_regs->hw_ocotp_ctrl);
+
+ /* Program the data. */
+ writel(mask, &ocotp_regs->hw_ocotp_data);
+
+ udelay(10);
+
+ ret = mxs_ocotp_wait_busy_clear();
+ if (ret) {
+ puts("Failed waiting for ready state!\n");
+ goto fail;
+ }
+
+fail:
+ mxs_ocotp_scale_vddio(0, &vddio_val);
+ ret = mxs_ocotp_scale_hclk(0, &hclk_val);
+ if (ret) {
+ puts("Failed scaling up the HCLK!\n");
+ return ret;
+ }
+
+ return ret;
+}
+
+static int mxs_ocotp_read_fuse(uint32_t reg, uint32_t *val)
+{
+ int ret;
+
+ /* Register offset from CUST0 */
+ reg = ((uint32_t)&ocotp_regs->hw_ocotp_cust0) + (reg << 4);
+
+ ret = mxs_ocotp_wait_busy_clear();
+ if (ret) {
+ puts("Failed waiting for ready state!\n");
+ return ret;
+ }
+
+ mxs_ocotp_clear_error();
+
+ ret = mxs_ocotp_read_bank_open(1);
+ if (ret) {
+ puts("Failed opening banks for reading!\n");
+ return ret;
+ }
+
+ *val = readl(reg);
+
+ ret = mxs_ocotp_read_bank_open(0);
+ if (ret) {
+ puts("Failed closing banks for reading!\n");
+ return ret;
+ }
+
+ return ret;
+}
+
+static int mxs_ocotp_valid(u32 bank, u32 word)
+{
+ if (bank > 4)
+ return -EINVAL;
+ if (word > 7)
+ return -EINVAL;
+ return 0;
+}
+
+/*
+ * The 'fuse' command API
+ */
+int fuse_read(u32 bank, u32 word, u32 *val)
+{
+ int ret;
+
+ ret = mxs_ocotp_valid(bank, word);
+ if (ret)
+ return ret;
+
+ return mxs_ocotp_read_fuse((bank << 3) | word, val);
+}
+
+int fuse_prog(u32 bank, u32 word, u32 val)
+{
+ int ret;
+
+ ret = mxs_ocotp_valid(bank, word);
+ if (ret)
+ return ret;
+
+ return mxs_ocotp_write_fuse((bank << 3) | word, val);
+}
+
+int fuse_sense(u32 bank, u32 word, u32 *val)
+{
+ /* We do not support sensing :-( */
+ return -EINVAL;
+}
+
+int fuse_override(u32 bank, u32 word, u32 val)
+{
+ /* We do not support overriding :-( */
+ return -EINVAL;
+}
diff --git a/include/configs/mxs.h b/include/configs/mxs.h
index 363b277..10e5c3e 100644
--- a/include/configs/mxs.h
+++ b/include/configs/mxs.h
@@ -175,6 +175,11 @@
#define CONFIG_SYS_NAND_5_ADDR_CYCLE
#endif

+/* OCOTP */
+#ifdef CONFIG_CMD_FUSE
+#define CONFIG_MXS_OCOTP
+#endif
+
/* SPI */
#ifdef CONFIG_CMD_SPI
#define CONFIG_HARD_SPI
--
1.8.5.3