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

From: Sanchayan Maity
Date: Thu Aug 06 2015 - 11:30:55 EST

The patch adds support for the On Chip One Time Programmable Peripheral
(OCOTP) on the Vybrid platform.

Signed-off-by: Sanchayan Maity <maitysanchayan@xxxxxxxxx>
---
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
+ 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 <sanchayan.maity@xxxxxxxxxxx>
+ *
+ * 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)
+
+#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)
+{
+ 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,
+};
+
+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 <sanchayan.maity@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Vybrid OCOTP driver");
+MODULE_LICENSE("GPL v2");
--
2.5.0

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