u-boot/drivers/misc/mxs_ocotp.c
Marek Vasut 2bbcccf552 ARM: mxs: Add OCOTP driver
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>
2014-03-31 18:28:50 +02:00

312 lines
6.6 KiB
C

/*
* 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;
}