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path: root/drivers/nvmem/bcm-ocotp.c
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Diffstat (limited to 'drivers/nvmem/bcm-ocotp.c')
-rw-r--r--drivers/nvmem/bcm-ocotp.c316
1 files changed, 316 insertions, 0 deletions
diff --git a/drivers/nvmem/bcm-ocotp.c b/drivers/nvmem/bcm-ocotp.c
new file mode 100644
index 000000000..a128c7f5e
--- /dev/null
+++ b/drivers/nvmem/bcm-ocotp.c
@@ -0,0 +1,316 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (C) 2016 Broadcom
+
+#include <linux/acpi.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/of_device.h>
+#include <linux/platform_device.h>
+
+/*
+ * # of tries for OTP Status. The time to execute a command varies. The slowest
+ * commands are writes which also vary based on the # of bits turned on. Writing
+ * 0xffffffff takes ~3800 us.
+ */
+#define OTPC_RETRIES 5000
+
+/* Sequence to enable OTP program */
+#define OTPC_PROG_EN_SEQ { 0xf, 0x4, 0x8, 0xd }
+
+/* OTPC Commands */
+#define OTPC_CMD_READ 0x0
+#define OTPC_CMD_OTP_PROG_ENABLE 0x2
+#define OTPC_CMD_OTP_PROG_DISABLE 0x3
+#define OTPC_CMD_PROGRAM 0x8
+
+/* OTPC Status Bits */
+#define OTPC_STAT_CMD_DONE BIT(1)
+#define OTPC_STAT_PROG_OK BIT(2)
+
+/* OTPC register definition */
+#define OTPC_MODE_REG_OFFSET 0x0
+#define OTPC_MODE_REG_OTPC_MODE 0
+#define OTPC_COMMAND_OFFSET 0x4
+#define OTPC_COMMAND_COMMAND_WIDTH 6
+#define OTPC_CMD_START_OFFSET 0x8
+#define OTPC_CMD_START_START 0
+#define OTPC_CPU_STATUS_OFFSET 0xc
+#define OTPC_CPUADDR_REG_OFFSET 0x28
+#define OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH 16
+#define OTPC_CPU_WRITE_REG_OFFSET 0x2c
+
+#define OTPC_CMD_MASK (BIT(OTPC_COMMAND_COMMAND_WIDTH) - 1)
+#define OTPC_ADDR_MASK (BIT(OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH) - 1)
+
+
+struct otpc_map {
+ /* in words. */
+ u32 otpc_row_size;
+ /* 128 bit row / 4 words support. */
+ u16 data_r_offset[4];
+ /* 128 bit row / 4 words support. */
+ u16 data_w_offset[4];
+};
+
+static struct otpc_map otp_map = {
+ .otpc_row_size = 1,
+ .data_r_offset = {0x10},
+ .data_w_offset = {0x2c},
+};
+
+static struct otpc_map otp_map_v2 = {
+ .otpc_row_size = 2,
+ .data_r_offset = {0x10, 0x5c},
+ .data_w_offset = {0x2c, 0x64},
+};
+
+struct otpc_priv {
+ struct device *dev;
+ void __iomem *base;
+ const struct otpc_map *map;
+ struct nvmem_config *config;
+};
+
+static inline void set_command(void __iomem *base, u32 command)
+{
+ writel(command & OTPC_CMD_MASK, base + OTPC_COMMAND_OFFSET);
+}
+
+static inline void set_cpu_address(void __iomem *base, u32 addr)
+{
+ writel(addr & OTPC_ADDR_MASK, base + OTPC_CPUADDR_REG_OFFSET);
+}
+
+static inline void set_start_bit(void __iomem *base)
+{
+ writel(1 << OTPC_CMD_START_START, base + OTPC_CMD_START_OFFSET);
+}
+
+static inline void reset_start_bit(void __iomem *base)
+{
+ writel(0, base + OTPC_CMD_START_OFFSET);
+}
+
+static inline void write_cpu_data(void __iomem *base, u32 value)
+{
+ writel(value, base + OTPC_CPU_WRITE_REG_OFFSET);
+}
+
+static int poll_cpu_status(void __iomem *base, u32 value)
+{
+ u32 status;
+ u32 retries;
+
+ for (retries = 0; retries < OTPC_RETRIES; retries++) {
+ status = readl(base + OTPC_CPU_STATUS_OFFSET);
+ if (status & value)
+ break;
+ udelay(1);
+ }
+ if (retries == OTPC_RETRIES)
+ return -EAGAIN;
+
+ return 0;
+}
+
+static int enable_ocotp_program(void __iomem *base)
+{
+ static const u32 vals[] = OTPC_PROG_EN_SEQ;
+ int i;
+ int ret;
+
+ /* Write the magic sequence to enable programming */
+ set_command(base, OTPC_CMD_OTP_PROG_ENABLE);
+ for (i = 0; i < ARRAY_SIZE(vals); i++) {
+ write_cpu_data(base, vals[i]);
+ set_start_bit(base);
+ ret = poll_cpu_status(base, OTPC_STAT_CMD_DONE);
+ reset_start_bit(base);
+ if (ret)
+ return ret;
+ }
+
+ return poll_cpu_status(base, OTPC_STAT_PROG_OK);
+}
+
+static int disable_ocotp_program(void __iomem *base)
+{
+ int ret;
+
+ set_command(base, OTPC_CMD_OTP_PROG_DISABLE);
+ set_start_bit(base);
+ ret = poll_cpu_status(base, OTPC_STAT_PROG_OK);
+ reset_start_bit(base);
+
+ return ret;
+}
+
+static int bcm_otpc_read(void *context, unsigned int offset, void *val,
+ size_t bytes)
+{
+ struct otpc_priv *priv = context;
+ u32 *buf = val;
+ u32 bytes_read;
+ u32 address = offset / priv->config->word_size;
+ int i, ret;
+
+ for (bytes_read = 0; bytes_read < bytes;) {
+ set_command(priv->base, OTPC_CMD_READ);
+ set_cpu_address(priv->base, address++);
+ set_start_bit(priv->base);
+ ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE);
+ if (ret) {
+ dev_err(priv->dev, "otp read error: 0x%x", ret);
+ return -EIO;
+ }
+
+ for (i = 0; i < priv->map->otpc_row_size; i++) {
+ *buf++ = readl(priv->base +
+ priv->map->data_r_offset[i]);
+ bytes_read += sizeof(*buf);
+ }
+
+ reset_start_bit(priv->base);
+ }
+
+ return 0;
+}
+
+static int bcm_otpc_write(void *context, unsigned int offset, void *val,
+ size_t bytes)
+{
+ struct otpc_priv *priv = context;
+ u32 *buf = val;
+ u32 bytes_written;
+ u32 address = offset / priv->config->word_size;
+ int i, ret;
+
+ if (offset % priv->config->word_size)
+ return -EINVAL;
+
+ ret = enable_ocotp_program(priv->base);
+ if (ret)
+ return -EIO;
+
+ for (bytes_written = 0; bytes_written < bytes;) {
+ set_command(priv->base, OTPC_CMD_PROGRAM);
+ set_cpu_address(priv->base, address++);
+ for (i = 0; i < priv->map->otpc_row_size; i++) {
+ writel(*buf, priv->base + priv->map->data_w_offset[i]);
+ buf++;
+ bytes_written += sizeof(*buf);
+ }
+ set_start_bit(priv->base);
+ ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE);
+ reset_start_bit(priv->base);
+ if (ret) {
+ dev_err(priv->dev, "otp write error: 0x%x", ret);
+ return -EIO;
+ }
+ }
+
+ disable_ocotp_program(priv->base);
+
+ return 0;
+}
+
+static struct nvmem_config bcm_otpc_nvmem_config = {
+ .name = "bcm-ocotp",
+ .read_only = false,
+ .word_size = 4,
+ .stride = 4,
+ .reg_read = bcm_otpc_read,
+ .reg_write = bcm_otpc_write,
+};
+
+static const struct of_device_id bcm_otpc_dt_ids[] = {
+ { .compatible = "brcm,ocotp", .data = &otp_map },
+ { .compatible = "brcm,ocotp-v2", .data = &otp_map_v2 },
+ { },
+};
+MODULE_DEVICE_TABLE(of, bcm_otpc_dt_ids);
+
+static const struct acpi_device_id bcm_otpc_acpi_ids[] __maybe_unused = {
+ { .id = "BRCM0700", .driver_data = (kernel_ulong_t)&otp_map },
+ { .id = "BRCM0701", .driver_data = (kernel_ulong_t)&otp_map_v2 },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(acpi, bcm_otpc_acpi_ids);
+
+static int bcm_otpc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+ struct otpc_priv *priv;
+ struct nvmem_device *nvmem;
+ int err;
+ u32 num_words;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->map = device_get_match_data(dev);
+ if (!priv->map)
+ return -ENODEV;
+
+ /* Get OTP base address register. */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ priv->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(priv->base)) {
+ dev_err(dev, "unable to map I/O memory\n");
+ return PTR_ERR(priv->base);
+ }
+
+ /* Enable CPU access to OTPC. */
+ writel(readl(priv->base + OTPC_MODE_REG_OFFSET) |
+ BIT(OTPC_MODE_REG_OTPC_MODE),
+ priv->base + OTPC_MODE_REG_OFFSET);
+ reset_start_bit(priv->base);
+
+ /* Read size of memory in words. */
+ err = device_property_read_u32(dev, "brcm,ocotp-size", &num_words);
+ if (err) {
+ dev_err(dev, "size parameter not specified\n");
+ return -EINVAL;
+ } else if (num_words == 0) {
+ dev_err(dev, "size must be > 0\n");
+ return -EINVAL;
+ }
+
+ bcm_otpc_nvmem_config.size = 4 * num_words;
+ bcm_otpc_nvmem_config.dev = dev;
+ bcm_otpc_nvmem_config.priv = priv;
+
+ if (priv->map == &otp_map_v2) {
+ bcm_otpc_nvmem_config.word_size = 8;
+ bcm_otpc_nvmem_config.stride = 8;
+ }
+
+ priv->config = &bcm_otpc_nvmem_config;
+
+ nvmem = devm_nvmem_register(dev, &bcm_otpc_nvmem_config);
+ if (IS_ERR(nvmem)) {
+ dev_err(dev, "error registering nvmem config\n");
+ return PTR_ERR(nvmem);
+ }
+
+ return 0;
+}
+
+static struct platform_driver bcm_otpc_driver = {
+ .probe = bcm_otpc_probe,
+ .driver = {
+ .name = "brcm-otpc",
+ .of_match_table = bcm_otpc_dt_ids,
+ .acpi_match_table = ACPI_PTR(bcm_otpc_acpi_ids),
+ },
+};
+module_platform_driver(bcm_otpc_driver);
+
+MODULE_DESCRIPTION("Broadcom OTPC driver");
+MODULE_LICENSE("GPL v2");