[PATCH v2 2/2] drivers: misc: Add driver to access ZynqMP efuses

lukas.funke-oss at weidmueller.com lukas.funke-oss at weidmueller.com
Wed May 15 14:41:25 CEST 2024


From: Lukas Funke <lukas.funke at weidmueller.com>

Add driver to access ZynqMP efuses. This is a u-boot port of [1].

[1] https://lore.kernel.org/all/20240224114516.86365-8-srinivas.kandagatla@linaro.org/

Signed-off-by: Lukas Funke <lukas.funke at weidmueller.com>
---

Changes in v2:
- Drop vendor specific fuse cmd, use existing fuse cmd
- Minor code refactoring (reverse x-mas tree)

 drivers/misc/Kconfig        |   8 +
 drivers/misc/Makefile       |   1 +
 drivers/misc/zynqmp_efuse.c | 324 ++++++++++++++++++++++++++++++++++++
 3 files changed, 333 insertions(+)
 create mode 100644 drivers/misc/zynqmp_efuse.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 6009d55f400..c07f50c9a76 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -298,6 +298,14 @@ config FSL_SEC_MON
 	  Security Monitor can be transitioned on any security failures,
 	  like software violations or hardware security violations.
 
+config ZYNQMP_EFUSE
+	bool "Enable ZynqMP eFUSE Driver"
+	depends on ZYNQMP_FIRMWARE
+	help
+	  Enable access to Zynq UltraScale (ZynqMP) eFUSEs thought PMU firmware
+	  interface. ZnyqMP has 256 eFUSEs where some of them are security related
+	  and cannot be read back (i.e. AES key).
+
 choice
 	prompt "Security monitor interaction endianess"
 	depends on FSL_SEC_MON
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index e53d52c47b3..68ba5648eab 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -92,3 +92,4 @@ obj-$(CONFIG_ESM_K3) += k3_esm.o
 obj-$(CONFIG_ESM_PMIC) += esm_pmic.o
 obj-$(CONFIG_SL28CPLD) += sl28cpld.o
 obj-$(CONFIG_SPL_SOCFPGA_DT_REG) += socfpga_dtreg.o
+obj-$(CONFIG_ZYNQMP_EFUSE) += zynqmp_efuse.o
diff --git a/drivers/misc/zynqmp_efuse.c b/drivers/misc/zynqmp_efuse.c
new file mode 100644
index 00000000000..98a39c1ebdd
--- /dev/null
+++ b/drivers/misc/zynqmp_efuse.c
@@ -0,0 +1,324 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2014 - 2015 Xilinx, Inc.
+ * Michal Simek <michal.simek at amd.com>
+ *
+ * (C) Copyright 2024 Weidmueller Interface GmbH
+ * Lukas Funke <lukas.funke at weidmueller.com>
+ */
+
+#include <compiler.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <zynqmp_firmware.h>
+#include <asm/dma-mapping.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <misc.h>
+
+#define SILICON_REVISION_MASK 0xF
+#define P_USER_0_64_UPPER_MASK	0x5FFF0000
+#define P_USER_127_LOWER_4_BIT_MASK 0xF
+#define WORD_INBYTES		(4)
+#define SOC_VER_SIZE		(0x4)
+#define SOC_VERSION_OFFSET	(0x0)
+#define EFUSE_START_OFFSET	(0xC)
+#define EFUSE_END_OFFSET	(0xFC)
+#define EFUSE_PUF_START_OFFSET	(0x100)
+#define EFUSE_PUF_MID_OFFSET	(0x140)
+#define EFUSE_PUF_END_OFFSET	(0x17F)
+#define EFUSE_NOT_ENABLED	(29)
+#define EFUSE_READ		(0)
+#define EFUSE_WRITE		(1)
+
+/**
+ * struct efuse_map_entry - offset and length of zynqmp fuses
+ * @offset:	offset of efuse to be read/write
+ * @length:	length of efuse
+ */
+struct efuse_map_entry {
+	u32 offset;
+	u32 length;
+};
+
+struct efuse_map_entry zynqmp_efuse_table[] = {
+	{0x000, 0x04}, /* soc revision */
+	{0x00c, 0x0c}, /* SoC DNA */
+	{0x020, 0x04}, /* efuse-usr0 */
+	{0x024, 0x04}, /* efuse-usr1 */
+	{0x028, 0x04}, /* efuse-usr2 */
+	{0x02c, 0x04}, /* efuse-usr3 */
+	{0x030, 0x04}, /* efuse-usr4 */
+	{0x034, 0x04}, /* efuse-usr5 */
+	{0x038, 0x04}, /* efuse-usr6 */
+	{0x03c, 0x04}, /* efuse-usr7 */
+	{0x040, 0x04}, /* efuse-miscusr */
+	{0x050, 0x04}, /* efuse-chash */
+	{0x054, 0x04}, /* efuse-pufmisc */
+	{0x058, 0x04}, /* efuse-sec */
+	{0x05c, 0x04}, /* efuse-spkid */
+	{0x060, 0x30}, /* efuse-aeskey */
+	{0x0a0, 0x30}, /* ppk0-hash */
+	{0x0d0, 0x30}, /* ppk1-hash */
+	{0x100, 0x7f}, /* pufuser */
+};
+
+/**
+ * struct xilinx_efuse - the basic structure
+ * @src:	address of the buffer to store the data to be write/read
+ * @size:	no of words to be read/write
+ * @offset:	offset to be read/write`
+ * @flag:	0 - represents efuse read and 1- represents efuse write
+ * @pufuserfuse:0 - represents non-puf efuses, offset is used for read/write
+ *		1 - represents puf user fuse row number.
+ *
+ * this structure stores all the required details to
+ * read/write efuse memory.
+ */
+struct xilinx_efuse {
+	u64 src;
+	u32 size;
+	u32 offset;
+	u32 flag;
+	u32 pufuserfuse;
+};
+
+static int zynqmp_efuse_get_length(u32 offset, u32 *base_offset, u32 *len)
+{
+	struct efuse_map_entry *fuse;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zynqmp_efuse_table); ++i) {
+		fuse = &zynqmp_efuse_table[i];
+		if (offset >= fuse->offset &&
+		    offset < fuse->offset + fuse->length) {
+			*base_offset = fuse->offset;
+			*len = fuse->length;
+			return 0;
+			}
+	}
+
+	return -ENOENT;
+}
+
+static int zynqmp_efuse_access(struct udevice *dev, unsigned int offset,
+			       void *val, size_t bytes, unsigned int flag,
+			       unsigned int pufflag)
+{
+	size_t words = bytes / WORD_INBYTES;
+	struct xilinx_efuse *efuse;
+	ulong dma_addr, dma_buf;
+	int ret, value;
+	char *data;
+
+	if (bytes % WORD_INBYTES != 0) {
+		dev_err(dev, "Bytes requested should be word aligned\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (pufflag == 0 && offset % WORD_INBYTES) {
+		dev_err(dev, "Offset requested should be word aligned\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (pufflag == 1 && flag == EFUSE_WRITE) {
+		memcpy(&value, val, bytes);
+		if ((offset == EFUSE_PUF_START_OFFSET ||
+		     offset == EFUSE_PUF_MID_OFFSET) &&
+		    value & P_USER_0_64_UPPER_MASK) {
+			dev_err(dev, "Only lower 4 bytes are allowed to be programmed in P_USER_0 & P_USER_64\n");
+			return -EOPNOTSUPP;
+		}
+
+		if (offset == EFUSE_PUF_END_OFFSET &&
+		    (value & P_USER_127_LOWER_4_BIT_MASK)) {
+			dev_err(dev, "Only MSB 28 bits are allowed to be programmed for P_USER_127\n");
+			return -EOPNOTSUPP;
+		}
+	}
+
+	efuse = dma_alloc_coherent(sizeof(struct xilinx_efuse), &dma_addr);
+	if (!efuse)
+		return -ENOMEM;
+
+	data = dma_alloc_coherent(bytes, &dma_buf);
+	if (!data) {
+		dma_free_coherent(efuse);
+		return -ENOMEM;
+	}
+
+	if (flag == EFUSE_WRITE) {
+		memcpy(data, val, bytes);
+		efuse->flag = EFUSE_WRITE;
+	} else {
+		efuse->flag = EFUSE_READ;
+	}
+
+	efuse->src = dma_buf;
+	efuse->size = words;
+	efuse->offset = offset;
+	efuse->pufuserfuse = pufflag;
+
+	flush_dcache_range((ulong)efuse, (ulong)efuse +
+				   roundup(sizeof(struct xilinx_efuse), ARCH_DMA_MINALIGN));
+	flush_dcache_range((ulong)data, (ulong)data +
+				   roundup(sizeof(struct xilinx_efuse), ARCH_DMA_MINALIGN));
+
+	zynqmp_pm_efuse_access(dma_addr, (u32 *)&ret);
+	if (ret != 0) {
+		if (ret == EFUSE_NOT_ENABLED) {
+			dev_err(dev, "efuse access is not enabled\n");
+			ret = -EOPNOTSUPP;
+			goto END;
+		}
+		dev_err(dev, "Error in efuse read %x\n", ret);
+		ret = -EPERM;
+		goto END;
+	}
+
+	if (flag == EFUSE_READ)
+		memcpy(val, data, bytes);
+END:
+
+	dma_free_coherent(efuse);
+	dma_free_coherent(data);
+
+	return ret;
+}
+
+static int zynqmp_nvmem_read(struct udevice *dev, int offset,
+			     void *val, int bytes)
+{
+	int ret, pufflag = 0;
+	int idcode, version;
+
+	if (offset >= EFUSE_PUF_START_OFFSET && offset <= EFUSE_PUF_END_OFFSET)
+		pufflag = 1;
+
+	dev_dbg(dev, "reading from offset=0x%x, bytes=%d\n", offset, bytes);
+
+	switch (offset) {
+	/* Soc version offset is zero */
+	case SOC_VERSION_OFFSET:
+		if (bytes != SOC_VER_SIZE)
+			return -EOPNOTSUPP;
+
+		ret = zynqmp_pm_get_chipid((u32 *)&idcode, (u32 *)&version);
+		if (ret < 0)
+			return ret;
+
+		*(int *)val = version & SILICON_REVISION_MASK;
+		break;
+	/* Efuse offset starts from 0xc */
+	case EFUSE_START_OFFSET ... EFUSE_END_OFFSET:
+	case EFUSE_PUF_START_OFFSET ... EFUSE_PUF_END_OFFSET:
+		ret = zynqmp_efuse_access(dev, offset, val,
+					  bytes, EFUSE_READ, pufflag);
+		break;
+	default:
+		*(u32 *)val = 0xDEADBEEF;
+		ret = 0;
+		break;
+	}
+
+	return ret;
+}
+
+static int zynqmp_nvmem_write(struct udevice *dev, int offset, const void *val,
+			      int bytes)
+{
+	int pufflag = 0;
+
+	dev_dbg(dev, "writing to offset=0x%x, bytes=%d", offset, bytes);
+
+	if (offset < EFUSE_START_OFFSET || offset > EFUSE_PUF_END_OFFSET)
+		return -EOPNOTSUPP;
+
+	if (offset >= EFUSE_PUF_START_OFFSET && offset <= EFUSE_PUF_END_OFFSET)
+		pufflag = 1;
+
+	return zynqmp_efuse_access(dev, offset,
+				   (void *)val, bytes, EFUSE_WRITE, pufflag);
+}
+
+int fuse_read(u32 bank, u32 word, u32 *val)
+{
+	u32 base_offset, offset, len;
+	struct udevice *dev;
+	u8 buf[128];
+	int ret;
+
+	memset(buf, 0, sizeof(buf));
+
+	ret = uclass_get_device_by_driver(UCLASS_MISC,
+					  DM_DRIVER_GET(zynqmp_efuse), &dev);
+	if (ret)
+		return log_msg_ret("uclass_drv", ret);
+
+	ret = zynqmp_efuse_get_length(word, &base_offset, &len);
+	if (ret)
+		return log_msg_ret("efuse_offset", ret);
+
+	ret = misc_read(dev, base_offset, (void *)buf, len);
+	if (ret)
+		return log_msg_ret("misc_read", ret);
+
+	offset = word - base_offset;
+	*val = ((u32 *)buf)[offset];
+
+	return 0;
+}
+
+int fuse_prog(u32 bank, u32 word, u32 val)
+{
+	u32 base_offset, len;
+	struct udevice *dev;
+	int ret;
+
+	ret = zynqmp_efuse_get_length(word, &base_offset, &len);
+	if (ret)
+		return log_msg_ret("efuse_offset", ret);
+
+	ret = uclass_get_device_by_driver(UCLASS_MISC,
+					  DM_DRIVER_GET(zynqmp_efuse), &dev);
+	if (ret)
+		return log_msg_ret("uclass_drv", ret);
+
+	if (word != base_offset || len != sizeof(val))
+		return -EINVAL;
+
+	ret = misc_write(dev, word, (void *)&val, sizeof(val));
+	if (ret)
+		return log_msg_ret("misc_write", ret);
+
+	return 0;
+}
+
+int fuse_sense(u32 bank, u32 word, u32 *val)
+{
+	/* We do not support sense */
+	return -ENOSYS;
+}
+
+int fuse_override(u32 bank, u32 word, u32 val)
+{
+	/* We do not support overriding */
+	return -ENOSYS;
+}
+
+static const struct udevice_id zynqmp_efuse_match[] = {
+	{ .compatible = "xlnx,zynqmp-nvmem-fw", },
+	{ /* sentinel */ },
+};
+
+static const struct misc_ops zynqmp_efuse_ops = {
+	.read = zynqmp_nvmem_read,
+	.write = zynqmp_nvmem_write,
+};
+
+U_BOOT_DRIVER(zynqmp_efuse) = {
+	.name = "zynqmp_efuse",
+	.id = UCLASS_MISC,
+	.of_match = zynqmp_efuse_match,
+	.ops = &zynqmp_efuse_ops,
+};
-- 
2.30.2



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