The driver allows read-only support to e.g. the Hardware UID, which
could in future be used to derive a MAC like U-Boot does.

Signed-off-by: Ahmad Fatoum <[email protected]>
---
 drivers/nvmem/Kconfig          |   8 +
 drivers/nvmem/Makefile         |   1 +
 drivers/nvmem/rockchip-efuse.c | 299 +++++++++++++++++++++++++++++++++
 3 files changed, 308 insertions(+)
 create mode 100644 drivers/nvmem/rockchip-efuse.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 7b1ebe1d689d..ea1156918a34 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -84,4 +84,12 @@ config STARFIVE_OTP
          This adds support for the StarFive OTP controller. Only reading
          is currently supported.
 
+config ROCKCHIP_EFUSE
+       tristate "Rockchip eFuse Support"
+       depends on ARCH_ROCKCHIP || COMPILE_TEST
+       depends on OFDEVICE
+       help
+         This is a simple drive to dump specified values of Rockchip SoC
+         from eFuse, such as CPU ID.
+
 endif
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 586591961215..2261816c189c 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -25,3 +25,4 @@ obj-$(CONFIG_STM32_BSEC)      += nvmem_bsec.o
 nvmem_bsec-y                   := bsec.o
 
 obj-$(CONFIG_STARFIVE_OTP)     += starfive-otp.o
+obj-$(CONFIG_ROCKCHIP_EFUSE)   += rockchip-efuse.o
diff --git a/drivers/nvmem/rockchip-efuse.c b/drivers/nvmem/rockchip-efuse.c
new file mode 100644
index 000000000000..24e7de0aa9ce
--- /dev/null
+++ b/drivers/nvmem/rockchip-efuse.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Rockchip eFuse Driver
+ *
+ * Copyright (c) 2015 Rockchip Electronics Co. Ltd.
+ * Author: Caesar Wang <[email protected]>
+ */
+
+#include <common.h>
+#include <linux/clk.h>
+#include <linux/overflow.h>
+#include <clock.h>
+#include <driver.h>
+#include <io.h>
+#include <linux/nvmem-provider.h>
+#include <of.h>
+#include <init.h>
+
+#define clk_prepare_enable clk_enable
+#define clk_disable_unprepare clk_disable
+
+#define RK3288_A_SHIFT         6
+#define RK3288_A_MASK          0x3ff
+#define RK3288_PGENB           BIT(3)
+#define RK3288_LOAD            BIT(2)
+#define RK3288_STROBE          BIT(1)
+#define RK3288_CSB             BIT(0)
+
+#define RK3328_SECURE_SIZES    96
+#define RK3328_INT_STATUS      0x0018
+#define RK3328_DOUT            0x0020
+#define RK3328_AUTO_CTRL       0x0024
+#define RK3328_INT_FINISH      BIT(0)
+#define RK3328_AUTO_ENB                BIT(0)
+#define RK3328_AUTO_RD         BIT(1)
+
+#define RK3399_A_SHIFT         16
+#define RK3399_A_MASK          0x3ff
+#define RK3399_NBYTES          4
+#define RK3399_STROBSFTSEL     BIT(9)
+#define RK3399_RSB             BIT(7)
+#define RK3399_PD              BIT(5)
+#define RK3399_PGENB           BIT(3)
+#define RK3399_LOAD            BIT(2)
+#define RK3399_STROBE          BIT(1)
+#define RK3399_CSB             BIT(0)
+
+#define REG_EFUSE_CTRL         0x0000
+#define REG_EFUSE_DOUT         0x0004
+
+struct rockchip_efuse_chip {
+       struct device_d *dev;
+       void __iomem *base;
+       struct clk *clk;
+};
+
+static int rockchip_rk3288_efuse_read(void *context, unsigned int offset,
+                                     void *val, size_t bytes)
+{
+       struct rockchip_efuse_chip *efuse = context;
+       u8 *buf = val;
+       int ret;
+
+       ret = clk_prepare_enable(efuse->clk);
+       if (ret < 0) {
+               dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
+               return ret;
+       }
+
+       writel(RK3288_LOAD | RK3288_PGENB, efuse->base + REG_EFUSE_CTRL);
+       udelay(1);
+       while (bytes--) {
+               writel(readl(efuse->base + REG_EFUSE_CTRL) &
+                            (~(RK3288_A_MASK << RK3288_A_SHIFT)),
+                            efuse->base + REG_EFUSE_CTRL);
+               writel(readl(efuse->base + REG_EFUSE_CTRL) |
+                            ((offset++ & RK3288_A_MASK) << RK3288_A_SHIFT),
+                            efuse->base + REG_EFUSE_CTRL);
+               udelay(1);
+               writel(readl(efuse->base + REG_EFUSE_CTRL) |
+                            RK3288_STROBE, efuse->base + REG_EFUSE_CTRL);
+               udelay(1);
+               *buf++ = readb(efuse->base + REG_EFUSE_DOUT);
+               writel(readl(efuse->base + REG_EFUSE_CTRL) &
+                      (~RK3288_STROBE), efuse->base + REG_EFUSE_CTRL);
+               udelay(1);
+       }
+
+       /* Switch to standby mode */
+       writel(RK3288_PGENB | RK3288_CSB, efuse->base + REG_EFUSE_CTRL);
+
+       clk_disable_unprepare(efuse->clk);
+
+       return 0;
+}
+
+static int rockchip_rk3328_efuse_read(void *context, unsigned int offset,
+                                     void *val, size_t bytes)
+{
+       struct rockchip_efuse_chip *efuse = context;
+       unsigned int addr_start, addr_end, addr_offset, addr_len;
+       u32 out_value, status;
+       u8 *buf;
+       int ret, i = 0;
+
+       ret = clk_prepare_enable(efuse->clk);
+       if (ret < 0) {
+               dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
+               return ret;
+       }
+
+       /* 128 Byte efuse, 96 Byte for secure, 32 Byte for non-secure */
+       offset += RK3328_SECURE_SIZES;
+       addr_start = rounddown(offset, RK3399_NBYTES) / RK3399_NBYTES;
+       addr_end = roundup(offset + bytes, RK3399_NBYTES) / RK3399_NBYTES;
+       addr_offset = offset % RK3399_NBYTES;
+       addr_len = addr_end - addr_start;
+
+       buf = kzalloc(array3_size(addr_len, RK3399_NBYTES, sizeof(*buf)),
+                     GFP_KERNEL);
+       if (!buf) {
+               ret = -ENOMEM;
+               goto nomem;
+       }
+
+       while (addr_len--) {
+               writel(RK3328_AUTO_RD | RK3328_AUTO_ENB |
+                      ((addr_start++ & RK3399_A_MASK) << RK3399_A_SHIFT),
+                      efuse->base + RK3328_AUTO_CTRL);
+               udelay(4);
+               status = readl(efuse->base + RK3328_INT_STATUS);
+               if (!(status & RK3328_INT_FINISH)) {
+                       ret = -EIO;
+                       goto err;
+               }
+               out_value = readl(efuse->base + RK3328_DOUT);
+               writel(RK3328_INT_FINISH, efuse->base + RK3328_INT_STATUS);
+
+               memcpy(&buf[i], &out_value, RK3399_NBYTES);
+               i += RK3399_NBYTES;
+       }
+
+       memcpy(val, buf + addr_offset, bytes);
+err:
+       kfree(buf);
+nomem:
+       clk_disable_unprepare(efuse->clk);
+
+       return ret;
+}
+
+static int rockchip_rk3399_efuse_read(void *context, unsigned int offset,
+                                     void *val, size_t bytes)
+{
+       struct rockchip_efuse_chip *efuse = context;
+       unsigned int addr_start, addr_end, addr_offset, addr_len;
+       u32 out_value;
+       u8 *buf;
+       int ret, i = 0;
+
+       ret = clk_prepare_enable(efuse->clk);
+       if (ret < 0) {
+               dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
+               return ret;
+       }
+
+       addr_start = rounddown(offset, RK3399_NBYTES) / RK3399_NBYTES;
+       addr_end = roundup(offset + bytes, RK3399_NBYTES) / RK3399_NBYTES;
+       addr_offset = offset % RK3399_NBYTES;
+       addr_len = addr_end - addr_start;
+
+       buf = kzalloc(array3_size(addr_len, RK3399_NBYTES, sizeof(*buf)),
+                     GFP_KERNEL);
+       if (!buf) {
+               clk_disable_unprepare(efuse->clk);
+               return -ENOMEM;
+       }
+
+       writel(RK3399_LOAD | RK3399_PGENB | RK3399_STROBSFTSEL | RK3399_RSB,
+              efuse->base + REG_EFUSE_CTRL);
+       udelay(1);
+       while (addr_len--) {
+               writel(readl(efuse->base + REG_EFUSE_CTRL) | RK3399_STROBE |
+                      ((addr_start++ & RK3399_A_MASK) << RK3399_A_SHIFT),
+                      efuse->base + REG_EFUSE_CTRL);
+               udelay(1);
+               out_value = readl(efuse->base + REG_EFUSE_DOUT);
+               writel(readl(efuse->base + REG_EFUSE_CTRL) & (~RK3399_STROBE),
+                      efuse->base + REG_EFUSE_CTRL);
+               udelay(1);
+
+               memcpy(&buf[i], &out_value, RK3399_NBYTES);
+               i += RK3399_NBYTES;
+       }
+
+       /* Switch to standby mode */
+       writel(RK3399_PD | RK3399_CSB, efuse->base + REG_EFUSE_CTRL);
+
+       memcpy(val, buf + addr_offset, bytes);
+
+       kfree(buf);
+
+       clk_disable_unprepare(efuse->clk);
+
+       return 0;
+}
+
+static struct nvmem_config econfig = {
+       .name = "rockchip-efuse",
+       .stride = 1,
+       .word_size = 1,
+       .read_only = true,
+};
+
+static const struct of_device_id rockchip_efuse_match[] = {
+       /* deprecated but kept around for dts binding compatibility */
+       {
+               .compatible = "rockchip,rockchip-efuse",
+               .data = (void *)&rockchip_rk3288_efuse_read,
+       },
+       {
+               .compatible = "rockchip,rk3066a-efuse",
+               .data = (void *)&rockchip_rk3288_efuse_read,
+       },
+       {
+               .compatible = "rockchip,rk3188-efuse",
+               .data = (void *)&rockchip_rk3288_efuse_read,
+       },
+       {
+               .compatible = "rockchip,rk3228-efuse",
+               .data = (void *)&rockchip_rk3288_efuse_read,
+       },
+       {
+               .compatible = "rockchip,rk3288-efuse",
+               .data = (void *)&rockchip_rk3288_efuse_read,
+       },
+       {
+               .compatible = "rockchip,rk3368-efuse",
+               .data = (void *)&rockchip_rk3288_efuse_read,
+       },
+       {
+               .compatible = "rockchip,rk3328-efuse",
+               .data = (void *)&rockchip_rk3328_efuse_read,
+       },
+       {
+               .compatible = "rockchip,rk3399-efuse",
+               .data = (void *)&rockchip_rk3399_efuse_read,
+       },
+       { /* sentinel */},
+};
+MODULE_DEVICE_TABLE(of, rockchip_efuse_match);
+
+static int rockchip_efuse_probe(struct device_d *dev)
+{
+       struct resource *res;
+       struct nvmem_device *nvmem;
+       struct rockchip_efuse_chip *efuse;
+       const void *data;
+
+       data = device_get_match_data(dev);
+       if (!data) {
+               dev_err(dev, "failed to get match data\n");
+               return -EINVAL;
+       }
+
+       efuse = kzalloc(sizeof(struct rockchip_efuse_chip), GFP_KERNEL);
+       if (!efuse)
+               return -ENOMEM;
+
+       res = dev_request_mem_resource(dev, 0);
+       if (IS_ERR(res))
+               return PTR_ERR(res);
+
+       efuse->base = IOMEM(res->start);
+
+       efuse->clk = clk_get(dev, "pclk_efuse");
+       if (IS_ERR(efuse->clk))
+               return PTR_ERR(efuse->clk);
+
+       efuse->dev = dev;
+       if (of_property_read_u32(dev->device_node, "rockchip,efuse-size",
+                                &econfig.size))
+               econfig.size = resource_size(res);
+       econfig.reg_read = data;
+       econfig.priv = efuse;
+       econfig.dev = efuse->dev;
+       nvmem = nvmem_register(&econfig);
+
+       return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static struct driver_d rockchip_efuse_driver = {
+       .name = "rockchip-efuse",
+       .of_compatible = rockchip_efuse_match,
+       .probe = rockchip_efuse_probe,
+};
+device_platform_driver(rockchip_efuse_driver);
+MODULE_DESCRIPTION("rockchip_efuse driver");
+MODULE_LICENSE("GPL v2");
-- 
2.30.2


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