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author | Uladzimir Bely <u.bely@sam-solutions.net> | 2014-04-11 15:06:24 +0300 |
---|---|---|
committer | Sascha Hauer <s.hauer@pengutronix.de> | 2014-05-05 09:35:05 +0200 |
commit | 825fca396f2b3797d0a8335b81c854d951783112 (patch) | |
tree | 524ad73fded68e03ae7f35cad10a9f55b6c14a04 /arch/arm/mach-imx/ocotp.c | |
parent | e0afbe3f84bf13787282ecd2b466e6451e824193 (diff) | |
download | barebox-825fca396f2b3797d0a8335b81c854d951783112.tar.gz barebox-825fca396f2b3797d0a8335b81c854d951783112.tar.xz |
imx6: ocotp: Add On-Chip OTP registers write support
FUSEs (OTP registers) can be written via /dev/imx-ocotp character device.
For example, writing MAC 12:34:56:78:9A:BC can be performed as
> mw -l -d /dev/imx-ocotp 0x8c 0x00001234
> mw -l -d /dev/imx-ocotp 0x88 0x56789ABC
and reading as
> md -l -s /dev/imx-ocotp 0x88+8
00000088: 56789ABC 00001234
, where 0x88 (0x22*4) and 0x8C (0x23*4) are offsets of MAC OTP registers.
Notice: FUSEs are PROM, so "0" (unprogrammed) bits
can be replaced with "1" (but not vice versa) only once.
Also, for MAC there are convinient parameters:
> ocotp0.permanent_write_enable=1
> ocotp0.mac_addr=12:34:56:78:9A:BC
imx_ocotp 21bc000.ocotp: reloading shadow registers...
imx_ocotp 21bc000.ocotp: reloading shadow registers...
> echo $ocotp0.mac_addr
12:34:56:78:9A:BC
Signed-off-by: Uladzimir Bely <u.bely@sam-solutions.net>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'arch/arm/mach-imx/ocotp.c')
-rw-r--r-- | arch/arm/mach-imx/ocotp.c | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/arch/arm/mach-imx/ocotp.c b/arch/arm/mach-imx/ocotp.c index e36b484e27..476b3767a0 100644 --- a/arch/arm/mach-imx/ocotp.c +++ b/arch/arm/mach-imx/ocotp.c @@ -25,6 +25,8 @@ #include <net.h> #include <io.h> #include <of.h> +#include <clock.h> +#include <linux/clk.h> /* * a single MAC address reference has the form @@ -32,6 +34,292 @@ */ #define MAC_ADDRESS_PROPLEN (2 * sizeof(__be32)) +/* OCOTP Registers offsets */ +#define OCOTP_CTRL_SET 0x04 +#define OCOTP_CTRL_CLR 0x08 +#define OCOTP_TIMING 0x10 +#define OCOTP_DATA 0x20 +#define OCOTP_READ_CTRL 0x30 +#define OCOTP_READ_FUSE_DATA 0x40 + +/* OCOTP Registers bits and masks */ +#define OCOTP_CTRL_WR_UNLOCK 16 +#define OCOTP_CTRL_WR_UNLOCK_KEY 0x3E77 +#define OCOTP_CTRL_WR_UNLOCK_MASK 0xFFFF0000 +#define OCOTP_CTRL_ADDR 0 +#define OCOTP_CTRL_ADDR_MASK 0x0000007F +#define OCOTP_CTRL_BUSY (1 << 8) +#define OCOTP_CTRL_ERROR (1 << 9) +#define OCOTP_CTRL_RELOAD_SHADOWS (1 << 10) + +#define OCOTP_TIMING_STROBE_READ 16 +#define OCOTP_TIMING_STROBE_READ_MASK 0x003F0000 +#define OCOTP_TIMING_RELAX 12 +#define OCOTP_TIMING_RELAX_MASK 0x0000F000 +#define OCOTP_TIMING_STROBE_PROG 0 +#define OCOTP_TIMING_STROBE_PROG_MASK 0x00000FFF + +#define OCOTP_READ_CTRL_READ_FUSE 0x00000001 + +#define BF(value, field) (((value) << field) & field##_MASK) + +/* Other definitions */ +#define FUSE_REGS_COUNT (16 * 8) +#define IMX6_OTP_DATA_ERROR_VAL 0xBADABADA +#define DEF_RELAX 20 +#define MAC_OFFSET (0x22 * 4) +#define MAC_BYTES 8 + +struct ocotp_priv { + struct cdev cdev; + void __iomem *base; + struct clk *clk; + struct device_d dev; + int permanent_write_enable; + int sense_enable; + char ethaddr[6]; +}; + +static int imx6_ocotp_set_timing(struct ocotp_priv *priv) +{ + u32 clk_rate; + u32 relax, strobe_read, strobe_prog; + u32 timing; + + clk_rate = clk_get_rate(priv->clk); + + relax = clk_rate / (1000000000 / DEF_RELAX) - 1; + strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1; + strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1; + + timing = BF(relax, OCOTP_TIMING_RELAX); + timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ); + timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG); + + writel(timing, priv->base + OCOTP_TIMING); + + return 0; +} + +static int imx6_ocotp_wait_busy(u32 flags, struct ocotp_priv *priv) +{ + uint64_t start = get_time_ns(); + + while ((OCOTP_CTRL_BUSY | OCOTP_CTRL_ERROR | flags) & + readl(priv->base)) { + if (is_timeout(start, MSECOND)) { + /* Clear ERROR bit */ + writel(OCOTP_CTRL_ERROR, priv->base + OCOTP_CTRL_CLR); + return -ETIMEDOUT; + } + } + + return 0; +} + +static int imx6_ocotp_prepare(struct ocotp_priv *priv) +{ + int ret; + + ret = imx6_ocotp_set_timing(priv); + if (ret) + return ret; + + ret = imx6_ocotp_wait_busy(0, priv); + if (ret) + return ret; + + return 0; +} + +static int fuse_read_addr(u32 addr, u32 *pdata, struct ocotp_priv *priv) +{ + u32 ctrl_reg; + int ret; + + ctrl_reg = readl(priv->base); + ctrl_reg &= ~OCOTP_CTRL_ADDR_MASK; + ctrl_reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK; + ctrl_reg |= BF(addr, OCOTP_CTRL_ADDR); + writel(ctrl_reg, priv->base); + + writel(OCOTP_READ_CTRL_READ_FUSE, priv->base + OCOTP_READ_CTRL); + ret = imx6_ocotp_wait_busy(0, priv); + if (ret) + return ret; + + *pdata = readl(priv->base + OCOTP_READ_FUSE_DATA); + + return 0; +} + +int imx6_ocotp_read_one_u32(u32 index, u32 *pdata, struct ocotp_priv *priv) +{ + int ret; + + ret = imx6_ocotp_prepare(priv); + if (ret) { + dev_err(priv->cdev.dev, "failed to prepare read fuse 0x%08x\n", + index); + return ret; + } + + ret = fuse_read_addr(index, pdata, priv); + if (ret) { + dev_err(priv->cdev.dev, "failed to read fuse 0x%08x\n", index); + return ret; + } + + if (readl(priv->base) & OCOTP_CTRL_ERROR) { + dev_err(priv->cdev.dev, "bad read status at fuse 0x%08x\n", index); + return -EFAULT; + } + + return 0; +} + +static ssize_t imx6_ocotp_cdev_read(struct cdev *cdev, void *buf, + size_t count, loff_t offset, unsigned long flags) +{ + u32 index; + ssize_t read_count = 0; + int ret, i; + struct ocotp_priv *priv = container_of(cdev, struct ocotp_priv, cdev); + + index = offset >> 2; + count >>= 2; + + if (count > (FUSE_REGS_COUNT - index)) + count = FUSE_REGS_COUNT - index - 1; + + for (i = index; i < (index + count); i++) { + if (priv->sense_enable) { + ret = imx6_ocotp_read_one_u32(i, buf, priv); + if (ret) + return ret; + } else { + *(u32 *)buf = readl(priv->base + 0x400 + i * 0x10); + } + + buf += 4; + read_count++; + } + + return read_count << 2; +} + +static int fuse_blow_addr(u32 addr, u32 value, struct ocotp_priv *priv) +{ + u32 ctrl_reg; + int ret; + + /* Control register */ + ctrl_reg = readl(priv->base); + ctrl_reg &= ~OCOTP_CTRL_ADDR_MASK; + ctrl_reg |= BF(addr, OCOTP_CTRL_ADDR); + ctrl_reg |= BF(OCOTP_CTRL_WR_UNLOCK_KEY, OCOTP_CTRL_WR_UNLOCK); + writel(ctrl_reg, priv->base); + + writel(value, priv->base + OCOTP_DATA); + ret = imx6_ocotp_wait_busy(0, priv); + if (ret) + return ret; + + /* Write postamble */ + udelay(2000); + return 0; +} + +static int imx6_ocotp_reload_shadow(struct ocotp_priv *priv) +{ + dev_info(priv->cdev.dev, "reloading shadow registers...\n"); + writel(OCOTP_CTRL_RELOAD_SHADOWS, priv->base + OCOTP_CTRL_SET); + udelay(1); + + return imx6_ocotp_wait_busy(OCOTP_CTRL_RELOAD_SHADOWS, priv); +} + +int imx6_ocotp_blow_one_u32(u32 index, u32 data, u32 *pfused_value, + struct ocotp_priv *priv) +{ + int ret; + + ret = imx6_ocotp_prepare(priv); + if (ret) { + dev_err(priv->cdev.dev, "prepare to write failed\n"); + return ret; + } + + ret = fuse_blow_addr(index, data, priv); + if (ret) { + dev_err(priv->cdev.dev, "fuse blow failed\n"); + return ret; + } + + if (readl(priv->base) & OCOTP_CTRL_ERROR) { + dev_err(priv->cdev.dev, "bad write status\n"); + return -EFAULT; + } + + ret = imx6_ocotp_read_one_u32(index, pfused_value, priv); + + return ret; +} + +static ssize_t imx6_ocotp_cdev_write(struct cdev *cdev, const void *buf, + size_t count, loff_t offset, unsigned long flags) +{ + struct ocotp_priv *priv = cdev->priv; + int index, i; + ssize_t write_count = 0; + const u32 *data; + u32 pfuse; + int ret; + + /* We could do better, but currently this is what's implemented */ + if (offset & 0x3 || count & 0x3) { + dev_err(cdev->dev, "only u32 aligned writes allowed\n"); + return -EINVAL; + } + + index = offset >> 2; + count >>= 2; + + if (count > (FUSE_REGS_COUNT - index)) + count = FUSE_REGS_COUNT - index - 1; + + data = buf; + + for (i = index; i < (index + count); i++) { + if (priv->permanent_write_enable) { + ret = imx6_ocotp_blow_one_u32(i, *data, + &pfuse, priv); + if (ret < 0) { + goto out; + } + } else { + writel(*data, priv->base + 0x400 + i * 0x10); + } + + data++; + write_count++; + } + + ret = 0; + +out: + if (priv->permanent_write_enable) + imx6_ocotp_reload_shadow(priv); + + return ret < 0 ? ret : (write_count << 2); +} + +static struct file_operations imx6_ocotp_ops = { + .read = imx6_ocotp_cdev_read, + .write = imx6_ocotp_cdev_write, + .lseek = dev_lseek_default, +}; + static void imx_ocotp_init_dt(struct device_d *dev, void __iomem *base) { char mac[6]; @@ -70,9 +358,43 @@ static void imx_ocotp_init_dt(struct device_d *dev, void __iomem *base) } } +static int imx_ocotp_get_mac(struct param_d *param, void *priv) +{ + struct ocotp_priv *ocotp_priv = priv; + char buf[8]; + int i; + + imx6_ocotp_cdev_read(&ocotp_priv->cdev, buf, MAC_BYTES, MAC_OFFSET, 0); + + for (i = 0; i < 6; i++) + ocotp_priv->ethaddr[i] = buf[5 - i]; + + return 0; +} + +static int imx_ocotp_set_mac(struct param_d *param, void *priv) +{ + struct ocotp_priv *ocotp_priv = priv; + char buf[8]; + int i, ret; + + for (i = 0; i < 6; i++) + buf[5 - i] = ocotp_priv->ethaddr[i]; + buf[6] = 0; buf[7] = 0; + + ret = imx6_ocotp_cdev_write(&ocotp_priv->cdev, buf, MAC_BYTES, MAC_OFFSET, 0); + if (ret < 0) + return ret; + + return 0; +} + static int imx_ocotp_probe(struct device_d *dev) { void __iomem *base; + struct ocotp_priv *priv; + struct cdev *cdev; + int ret = 0; base = dev_request_mem_region(dev, 0); if (!base) @@ -80,6 +402,40 @@ static int imx_ocotp_probe(struct device_d *dev) imx_ocotp_init_dt(dev, base); + priv = xzalloc(sizeof(*priv)); + + priv->base = base; + priv->clk = clk_get(dev, NULL); + if (IS_ERR(priv->clk)) + return PTR_ERR(priv->clk); + + cdev = &priv->cdev; + cdev->dev = dev; + cdev->ops = &imx6_ocotp_ops; + cdev->priv = priv; + cdev->size = 192; + cdev->name = "imx-ocotp"; + if (cdev->name == NULL) + return -ENOMEM; + + ret = devfs_create(cdev); + + if (ret < 0) + return ret; + + strcpy(priv->dev.name, "ocotp"); + priv->dev.parent = dev; + register_device(&priv->dev); + + if (IS_ENABLED(CONFIG_IMX_OCOTP_WRITE)) { + dev_add_param_bool(&(priv->dev), "permanent_write_enable", + NULL, NULL, &priv->permanent_write_enable, NULL); + } + + dev_add_param_mac(&(priv->dev), "mac_addr", imx_ocotp_set_mac, + imx_ocotp_get_mac, priv->ethaddr, priv); + dev_add_param_bool(&(priv->dev), "sense_enable", NULL, NULL, &priv->sense_enable, priv); + return 0; } |