Subject: [PATCH v7 3/4] drivers: nvmem: Add Vybrid OCOTP support

From: [email-masked] (Srinivas Kandagatla)
Date: Mon, 10 Aug 2015 10:17:53 +0100

Hi Sanchayan,

Could you add Greg to the "to list" so that we can request him to pick 
this via his tree.

Few nits, other than that driver looks good.

On 06/08/15 16:27, 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 <[email-masked]>
> ---
>   drivers/nvmem/Kconfig       |  10 ++
>   drivers/nvmem/Makefile      |   2 +
>   drivers/nvmem/vf610-ocotp.c | 297 ++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 309 insertions(+)
>   create mode 100644 drivers/nvmem/vf610-ocotp.c
>
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 0b33014..bfd0c02 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
You could also add COMPILE_TEST which will ensure that its compile checked.
> +	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..25ee701
> --- /dev/null
> +++ b/drivers/nvmem/vf610-ocotp.c
> @@ -0,0 +1,297 @@
> +/*
> + * Copyright (C) 2015 Toradex AG.
> + *
> + * Author: Sanchayan Maity <[email-masked]>
> + *
> + * 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		0xFFFF0000
> +#define OCOTP_CTRL_ADDR				0
> +#define OCOTP_CTRL_ADDR_MASK			0x7F
> +#define OCOTP_CTRL_RELOAD_SHADOWS		(0x1 << 10)
> +#define OCOTP_CTRL_ERROR			(0x1 << 9)
> +#define OCOTP_CTRL_BUSY				(0x1 << 8)

we can use BIT and GENMASK variants here for most of the defines.
> +
> +#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		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)
Align it to the braces.
> +{
> +	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,
> +	.max_register = 0xCF0,
Cant we get this info from the resource_size() ?
> +};
> +
> +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);
> +	}
> +
> +	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 <[email-masked]>");
> +MODULE_DESCRIPTION("Vybrid OCOTP driver");
> +MODULE_LICENSE("GPL v2");
>