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nvmem: zynqmp_nvmem: Add support to access efuse

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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@amd.com>
Acked-by: Kalyani Akula <Kalyani.akula@amd.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20240224114516.86365-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Praveen Teja Kundanala 2024-02-24 11:45:12 +00:00 committed by Greg Kroah-Hartman
parent 29be47fcd6
commit 737c0c8d07
1 changed files with 176 additions and 10 deletions
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186
drivers/nvmem/zynqmp_nvmem.c
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@ -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
};
static int zynqmp_nvmem_read(void *context, unsigned int offset,
void *val, size_t bytes)
/**
* 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;
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;
dev_dbg(dev, "Read chipid val %x %x\n", idcode, version);
*(int *)val = version & SILICON_REVISION_MASK;
switch (offset) {
/* Soc version offset is zero */
case SOC_VERSION_OFFSET:
if (bytes != SOC_VER_SIZE)
return -EOPNOTSUPP;
return 0;
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;
if (offset >= EFUSE_PUF_START_OFFSET && offset <= EFUSE_PUF_END_OFFSET)
pufflag = 1;
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));
}