[PATCH V4 3/4] nvmem: zynqmp_nvmem: Add support to access efuse
Praveen Teja Kundanala
praveen.teja.kundanala at amd.com
Fri Feb 2 03:38:42 PST 2024
Add support to read/write efuse memory map of ZynqMP.
Below are the offsets of ZynqMP efuse memory map
0 - SOC version(read only)
0xC - 0xFC -ZynqMP specific purpose efuses
0x100 - 0x17F - Physical Unclonable Function(PUF)
efuses repurposed as user efuses
Signed-off-by: Praveen Teja Kundanala <praveen.teja.kundanala at amd.com>
---
drivers/nvmem/zynqmp_nvmem.c | 186 +++++++++++++++++++++++++++++++++--
1 file changed, 176 insertions(+), 10 deletions(-)
diff --git a/drivers/nvmem/zynqmp_nvmem.c b/drivers/nvmem/zynqmp_nvmem.c
index 391d8e88b270..8682adaacd69 100644
--- a/drivers/nvmem/zynqmp_nvmem.c
+++ b/drivers/nvmem/zynqmp_nvmem.c
@@ -4,6 +4,7 @@
* Copyright (C) 2022 - 2023, Advanced Micro Devices, Inc.
*/
+#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
@@ -11,24 +12,189 @@
#include <linux/firmware/xlnx-zynqmp.h>
#define SILICON_REVISION_MASK 0xF
+#define P_USER_0_64_UPPER_MASK GENMASK(31, 16)
+#define P_USER_127_LOWER_4_BIT_MASK GENMASK(3, 0)
+#define WORD_INBYTES 4
+#define SOC_VER_SIZE 0x4
+#define EFUSE_MEMORY_SIZE 0x177
+#define UNUSED_SPACE 0x8
+#define ZYNQMP_NVMEM_SIZE (SOC_VER_SIZE + UNUSED_SPACE + \
+ EFUSE_MEMORY_SIZE)
+#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
+/*
+ * efuse access type
+ */
+enum efuse_access {
+ EFUSE_READ = 0,
+ EFUSE_WRITE
+};
+
+/**
+ * struct xilinx_efuse - the basic structure
+ * @src: address of the buffer to store the data to be write/read
+ * @size: read/write word count
+ * @offset: read/write offset
+ * @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;
+ enum efuse_access flag;
+ u32 pufuserfuse;
+};
+
+static int zynqmp_efuse_access(void *context, unsigned int offset,
+ void *val, size_t bytes, enum efuse_access flag,
+ unsigned int pufflag)
+{
+ struct device *dev = context;
+ struct xilinx_efuse *efuse;
+ dma_addr_t dma_addr;
+ dma_addr_t dma_buf;
+ size_t words = bytes / WORD_INBYTES;
+ int ret;
+ int 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(dev, sizeof(struct xilinx_efuse),
+ &dma_addr, GFP_KERNEL);
+ if (!efuse)
+ return -ENOMEM;
-static int zynqmp_nvmem_read(void *context, unsigned int offset,
- void *val, size_t bytes)
+ data = dma_alloc_coherent(dev, sizeof(bytes),
+ &dma_buf, GFP_KERNEL);
+ if (!data) {
+ ret = -ENOMEM;
+ goto efuse_data_fail;
+ }
+
+ 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;
+
+ 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;
+ } else {
+ dev_err(dev, "Error in efuse read %x\n", ret);
+ ret = -EPERM;
+ }
+ goto efuse_access_err;
+ }
+
+ if (flag == EFUSE_READ)
+ memcpy(val, data, bytes);
+efuse_access_err:
+ dma_free_coherent(dev, sizeof(bytes),
+ data, dma_buf);
+efuse_data_fail:
+ dma_free_coherent(dev, sizeof(struct xilinx_efuse),
+ efuse, dma_addr);
+
+ return ret;
+}
+
+static int zynqmp_nvmem_read(void *context, unsigned int offset, void *val, size_t bytes)
{
struct device *dev = context;
int ret;
+ int pufflag = 0;
int idcode;
int version;
- ret = zynqmp_pm_get_chipid(&idcode, &version);
- if (ret < 0)
- return ret;
+ if (offset >= EFUSE_PUF_START_OFFSET && offset <= EFUSE_PUF_END_OFFSET)
+ pufflag = 1;
+
+ 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;
+
+ dev_dbg(dev, "Read chipid val %x %x\n", idcode, version);
+ *(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(context, offset, val,
+ bytes, EFUSE_READ, pufflag);
+ break;
+ default:
+ *(u32 *)val = 0xDEADBEEF;
+ ret = 0;
+ break;
+ }
+
+ return ret;
+}
+
+static int zynqmp_nvmem_write(void *context,
+ unsigned int offset, void *val, size_t bytes)
+{
+ int pufflag = 0;
+
+ if (offset < EFUSE_START_OFFSET || offset > EFUSE_PUF_END_OFFSET)
+ return -EOPNOTSUPP;
- dev_dbg(dev, "Read chipid val %x %x\n", idcode, version);
- *(int *)val = version & SILICON_REVISION_MASK;
+ if (offset >= EFUSE_PUF_START_OFFSET && offset <= EFUSE_PUF_END_OFFSET)
+ pufflag = 1;
- return 0;
+ return zynqmp_efuse_access(context, offset,
+ val, bytes, EFUSE_WRITE, pufflag);
}
static const struct of_device_id zynqmp_nvmem_match[] = {
@@ -45,11 +211,11 @@ static int zynqmp_nvmem_probe(struct platform_device *pdev)
econfig.name = "zynqmp-nvmem";
econfig.owner = THIS_MODULE;
econfig.word_size = 1;
- econfig.size = 1;
+ econfig.size = ZYNQMP_NVMEM_SIZE;
econfig.dev = dev;
econfig.add_legacy_fixed_of_cells = true;
- econfig.read_only = true;
econfig.reg_read = zynqmp_nvmem_read;
+ econfig.reg_write = zynqmp_nvmem_write;
return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &econfig));
}
--
2.37.6
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