[PATCH v8 3/4] drivers: nvmem: Add Vybrid OCOTP support

[srinivas.kandagatla@linaro.org (Srinivas Kandagatla)]

Hi Sanchayan,

On 10/08/15 15:11, Sanchayan Maity wrote:
> The patch adds support for the On Chip One Time Programmable Peripheral
> (OCOTP) on the Vybrid platform.
>
> Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
> ---
>   drivers/nvmem/Kconfig       |  10 ++
>   drivers/nvmem/Makefile      |   2 +
>   drivers/nvmem/vf610-ocotp.c | 301 ++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 313 insertions(+)
>   create mode 100644 drivers/nvmem/vf610-ocotp.c
>
Patch looks good to me,

Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>


--srini
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 0b33014..7af4c1d 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -47,4 +47,14 @@ config NVMEM_IMX_OCOTP
>   	  This driver can also be built as a module. If so, the module
>   	  will be called nvmem-imx-ocotp.
>
> +config NVMEM_VF610_OCOTP
> +	tristate "VF610_SoCs OCOTP support"
> +	depends on SOC_VF610 || COMPILE_TEST
> +	help
> +	  This is a driver for the 'OCOTP' peripheral available on Vybrid
> +	  devices like VF5xx and VF6xx.
> +
> +	  This driver can also be built as a module. If so, the module will
> +	  be called nvmem-vf610-ocotp.
> +
>   endif
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index b512d77..8a1eea8 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -12,3 +12,5 @@ obj-$(CONFIG_NVMEM_SUNXI_SID)	+= nvmem_sunxi_sid.o
>   nvmem_sunxi_sid-y		:= sunxi_sid.o
>   obj-$(CONFIG_NVMEM_IMX_OCOTP)	+= nvmem-imx-ocotp.o
>   nvmem-imx-ocotp-y		:= imx-ocotp.o
> +obj-$(CONFIG_NVMEM_VF610_OCOTP)	+= nvmem-vf610-ocotp.o
> +nvmem-vf610-ocotp-y		:= vf610-ocotp.o
> diff --git a/drivers/nvmem/vf610-ocotp.c b/drivers/nvmem/vf610-ocotp.c
> new file mode 100644
> index 0000000..9e18156
> --- /dev/null
> +++ b/drivers/nvmem/vf610-ocotp.c
> @@ -0,0 +1,301 @@
> +/*
> + * Copyright (C) 2015 Toradex AG.
> + *
> + * Author: Sanchayan Maity <sanchayan.maity@toradex.com>
> + *
> + * Based on the barebox ocotp driver,
> + * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>
> + *	Orex Computed Radiography
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * 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.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-provider.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +/* OCOTP Register Offsets */
> +#define OCOTP_CTRL_REG				0x00
> +#define OCOTP_CTRL_SET				0x04
> +#define OCOTP_CTRL_CLR				0x08
> +#define OCOTP_TIMING				0x10
> +#define OCOTP_DATA				0x20
> +#define OCOTP_READ_CTRL_REG			0x30
> +#define OCOTP_READ_FUSE_DATA			0x40
> +
> +/* OCOTP Register bits and masks */
> +#define OCOTP_CTRL_WR_UNLOCK			16
> +#define OCOTP_CTRL_WR_UNLOCK_KEY		0x3E77
> +#define OCOTP_CTRL_WR_UNLOCK_MASK		GENMASK(31, 16)
> +#define OCOTP_CTRL_ADDR				0
> +#define OCOTP_CTRL_ADDR_MASK			GENMASK(6, 0)
> +#define OCOTP_CTRL_RELOAD_SHADOWS		BIT(10)
> +#define OCOTP_CTRL_ERROR			BIT(9)
> +#define OCOTP_CTRL_BUSY				BIT(8)
> +
> +#define OCOTP_TIMING_STROBE_READ		16
> +#define OCOTP_TIMING_STROBE_READ_MASK		GENMASK(21, 16)
> +#define OCOTP_TIMING_RELAX			12
> +#define OCOTP_TIMING_RELAX_MASK			GENMASK(15, 12)
> +#define OCOTP_TIMING_STROBE_PROG		0
> +#define OCOTP_TIMING_STROBE_PROG_MASK		GENMASK(11, 0)
> +
> +#define OCOTP_READ_CTRL_READ_FUSE		0x1
> +
> +#define VF610_OCOTP_TIMEOUT			100000
> +
> +#define BF(value, field)		(((value) << field) & field##_MASK)
> +
> +#define DEF_RELAX				20
> +
> +static const int base_to_fuse_addr_mappings[][2] = {
> +	{0x400, 0x00},
> +	{0x410, 0x01},
> +	{0x420, 0x02},
> +	{0x450, 0x05},
> +	{0x4F0, 0x0F},
> +	{0x600, 0x20},
> +	{0x610, 0x21},
> +	{0x620, 0x22},
> +	{0x630, 0x23},
> +	{0x640, 0x24},
> +	{0x650, 0x25},
> +	{0x660, 0x26},
> +	{0x670, 0x27},
> +	{0x6F0, 0x2F},
> +	{0x880, 0x38},
> +	{0x890, 0x39},
> +	{0x8A0, 0x3A},
> +	{0x8B0, 0x3B},
> +	{0x8C0, 0x3C},
> +	{0x8D0, 0x3D},
> +	{0x8E0, 0x3E},
> +	{0x8F0, 0x3F},
> +	{0xC80, 0x78},
> +	{0xC90, 0x79},
> +	{0xCA0, 0x7A},
> +	{0xCB0, 0x7B},
> +	{0xCC0, 0x7C},
> +	{0xCD0, 0x7D},
> +	{0xCE0, 0x7E},
> +	{0xCF0, 0x7F},
> +};
> +
> +struct vf610_ocotp {
> +	void __iomem *base;
> +	struct clk *clk;
> +	struct device *dev;
> +	struct nvmem_device *nvmem;
> +	int timing;
> +};
> +
> +static int vf610_ocotp_wait_busy(void __iomem *base)
> +{
> +	int timeout = VF610_OCOTP_TIMEOUT;
> +
> +	while ((readl(base) & OCOTP_CTRL_BUSY) && --timeout)
> +		udelay(10);
> +
> +	if (!timeout) {
> +		writel(OCOTP_CTRL_ERROR, base + OCOTP_CTRL_CLR);
> +		return -ETIMEDOUT;
> +	}
> +
> +	udelay(10);
> +
> +	return 0;
> +}
> +
> +static int vf610_ocotp_calculate_timing(struct vf610_ocotp *ocotp_dev)
> +{
> +	u32 clk_rate;
> +	u32 relax, strobe_read, strobe_prog;
> +	u32 timing;
> +
> +	clk_rate = clk_get_rate(ocotp_dev->clk);
> +
> +	/* Refer section OTP read/write timing parameters in TRM */
> +	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);
> +
> +	return timing;
> +}
> +
> +static int vf610_get_fuse_address(int base_addr_offset)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(base_to_fuse_addr_mappings); i++) {
> +		if (base_to_fuse_addr_mappings[i][0] == base_addr_offset)
> +			return base_to_fuse_addr_mappings[i][1];
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int vf610_ocotp_write(void *context, const void *data, size_t count)
> +{
> +	return 0;
> +}
> +
> +static int vf610_ocotp_read(void *context,
> +			const void *off, size_t reg_size,
> +			void *val, size_t val_size)
> +{
> +	struct vf610_ocotp *ocotp = context;
> +	unsigned int offset = *(u32 *)off;
> +	u32 reg, *buf = val;
> +	int fuse_addr;
> +	int ret;
> +
> +	while (val_size > 0) {
> +		fuse_addr = vf610_get_fuse_address(offset);
> +		if (fuse_addr > 0) {
> +			writel(ocotp->timing, ocotp->base + OCOTP_TIMING);
> +			ret = vf610_ocotp_wait_busy(ocotp->base + OCOTP_CTRL_REG);
> +			if (ret)
> +				return ret;
> +
> +			reg = readl(ocotp->base + OCOTP_CTRL_REG);
> +			reg &= ~OCOTP_CTRL_ADDR_MASK;
> +			reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
> +			reg |= BF(fuse_addr, OCOTP_CTRL_ADDR);
> +			writel(reg, ocotp->base + OCOTP_CTRL_REG);
> +
> +			writel(OCOTP_READ_CTRL_READ_FUSE,
> +				ocotp->base + OCOTP_READ_CTRL_REG);
> +			ret = vf610_ocotp_wait_busy(ocotp->base + OCOTP_CTRL_REG);
> +			if (ret)
> +				return ret;
> +
> +			if (readl(ocotp->base) & OCOTP_CTRL_ERROR) {
> +				dev_dbg(ocotp->dev, "Error reading from fuse address %x\n",
> +					fuse_addr);
> +				writel(OCOTP_CTRL_ERROR, ocotp->base + OCOTP_CTRL_CLR);
> +			}
> +
> +			/*
> +			 * In case of error, we do not abort and expect to read
> +			 * 0xBADABADA as mentioned by the TRM. We just read this
> +			 * value and return.
> +			 */
> +			*buf = readl(ocotp->base + OCOTP_READ_FUSE_DATA);
> +		} else {
> +			*buf = 0;
> +		}
> +
> +		buf++;
> +		val_size--;
> +		offset += reg_size;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct regmap_bus vf610_ocotp_bus = {
> +	.read = vf610_ocotp_read,
> +	.write = vf610_ocotp_write,
> +	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +};
> +
> +static struct regmap_config ocotp_regmap_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +};
> +
> +static struct nvmem_config ocotp_config = {
> +	.name = "ocotp",
> +	.owner = THIS_MODULE,
> +};
> +
> +static const struct of_device_id ocotp_of_match[] = {
> +	{ .compatible = "fsl,vf610-ocotp", },
> +	{/* sentinel */},
> +};
> +MODULE_DEVICE_TABLE(of, ocotp_of_match);
> +
> +static int vf610_ocotp_remove(struct platform_device *pdev)
> +{
> +	struct vf610_ocotp *ocotp_dev = platform_get_drvdata(pdev);
> +
> +	return nvmem_unregister(ocotp_dev->nvmem);
> +}
> +
> +static int vf610_ocotp_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	struct regmap *regmap;
> +	struct vf610_ocotp *ocotp_dev;
> +
> +	ocotp_dev = devm_kzalloc(&pdev->dev,
> +			sizeof(struct vf610_ocotp), GFP_KERNEL);
> +	if (!ocotp_dev)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	ocotp_dev->base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(ocotp_dev->base))
> +		return PTR_ERR(ocotp_dev->base);
> +
> +	ocotp_dev->clk = devm_clk_get(dev, "ocotp");
> +	if (IS_ERR(ocotp_dev->clk)) {
> +		dev_err(dev, "failed getting clock, err = %ld\n",
> +			PTR_ERR(ocotp_dev->clk));
> +		return PTR_ERR(ocotp_dev->clk);
> +	}
> +
> +	ocotp_regmap_config.max_register = resource_size(res);
> +	regmap = devm_regmap_init(dev,
> +		&vf610_ocotp_bus, ocotp_dev, &ocotp_regmap_config);
> +	if (IS_ERR(regmap)) {
> +		dev_err(dev, "regmap init failed\n");
> +		return PTR_ERR(regmap);
> +	}
> +	ocotp_config.dev = dev;
> +
> +	ocotp_dev->nvmem = nvmem_register(&ocotp_config);
> +	if (IS_ERR(ocotp_dev->nvmem))
> +		return PTR_ERR(ocotp_dev->nvmem);
> +
> +	ocotp_dev->dev = dev;
> +	platform_set_drvdata(pdev, ocotp_dev);
> +
> +	ocotp_dev->timing = vf610_ocotp_calculate_timing(ocotp_dev);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver vf610_ocotp_driver = {
> +	.probe = vf610_ocotp_probe,
> +	.remove = vf610_ocotp_remove,
> +	.driver = {
> +		.name = "vf610-ocotp",
> +		.of_match_table = ocotp_of_match,
> +	},
> +};
> +module_platform_driver(vf610_ocotp_driver);
> +MODULE_AUTHOR("Sanchayan Maity <sanchayan.maity@toradex.com>");
> +MODULE_DESCRIPTION("Vybrid OCOTP driver");
> +MODULE_LICENSE("GPL v2");
>