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authorWolfram Sang <wsa@kernel.org>2020-09-27 16:16:24 +0300
committerWolfram Sang <wsa@kernel.org>2020-09-27 16:16:24 +0300
commit668ba5e690369b38a185943e84ecb7ac04ab5d58 (patch)
tree4856b4b251c0a90d63814cb882e8b0628baead6f /drivers/misc
parent9b65b020fff70bc070c4cb8fcf8ea8a1f70b111b (diff)
parent61f764c307f6b2079b7af0d4fb7951402b824967 (diff)
downloadlinux-668ba5e690369b38a185943e84ecb7ac04ab5d58.tar.xz
Merge tag 'at24-updates-for-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux into i2c/for-5.10
at24 updates for v5.10 - add support for masking sensitive data in VAIO EEPROMs - set the nvmem TYPE to NVMEM_TYPE_EEPROM - add support for the new 'label' property - set the nvmem ID to NVMEM_DEVID_AUTO by default (for backward compatibility) or to NVMEM_DEVID_NONE if label is defined
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/eeprom/at24.c71
1 files changed, 64 insertions, 7 deletions
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 2591c21b2b5d..4aa96d8e78ef 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -8,6 +8,7 @@
#include <linux/acpi.h>
#include <linux/bitops.h>
+#include <linux/capability.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/init.h>
@@ -89,6 +90,7 @@ struct at24_data {
struct nvmem_device *nvmem;
struct regulator *vcc_reg;
+ void (*read_post)(unsigned int off, char *buf, size_t count);
/*
* Some chips tie up multiple I2C addresses; dummy devices reserve
@@ -121,6 +123,7 @@ MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");
struct at24_chip_data {
u32 byte_len;
u8 flags;
+ void (*read_post)(unsigned int off, char *buf, size_t count);
};
#define AT24_CHIP_DATA(_name, _len, _flags) \
@@ -128,6 +131,32 @@ struct at24_chip_data {
.byte_len = _len, .flags = _flags, \
}
+#define AT24_CHIP_DATA_CB(_name, _len, _flags, _read_post) \
+ static const struct at24_chip_data _name = { \
+ .byte_len = _len, .flags = _flags, \
+ .read_post = _read_post, \
+ }
+
+static void at24_read_post_vaio(unsigned int off, char *buf, size_t count)
+{
+ int i;
+
+ if (capable(CAP_SYS_ADMIN))
+ return;
+
+ /*
+ * Hide VAIO private settings to regular users:
+ * - BIOS passwords: bytes 0x00 to 0x0f
+ * - UUID: bytes 0x10 to 0x1f
+ * - Serial number: 0xc0 to 0xdf
+ */
+ for (i = 0; i < count; i++) {
+ if ((off + i <= 0x1f) ||
+ (off + i >= 0xc0 && off + i <= 0xdf))
+ buf[i] = 0;
+ }
+}
+
/* needs 8 addresses as A0-A2 are ignored */
AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR);
/* old variants can't be handled with this generic entry! */
@@ -144,6 +173,10 @@ AT24_CHIP_DATA(at24_data_24mac602, 64 / 8,
/* spd is a 24c02 in memory DIMMs */
AT24_CHIP_DATA(at24_data_spd, 2048 / 8,
AT24_FLAG_READONLY | AT24_FLAG_IRUGO);
+/* 24c02_vaio is a 24c02 on some Sony laptops */
+AT24_CHIP_DATA_CB(at24_data_24c02_vaio, 2048 / 8,
+ AT24_FLAG_READONLY | AT24_FLAG_IRUGO,
+ at24_read_post_vaio);
AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0);
AT24_CHIP_DATA(at24_data_24cs04, 16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
@@ -177,6 +210,7 @@ static const struct i2c_device_id at24_ids[] = {
{ "24mac402", (kernel_ulong_t)&at24_data_24mac402 },
{ "24mac602", (kernel_ulong_t)&at24_data_24mac602 },
{ "spd", (kernel_ulong_t)&at24_data_spd },
+ { "24c02-vaio", (kernel_ulong_t)&at24_data_24c02_vaio },
{ "24c04", (kernel_ulong_t)&at24_data_24c04 },
{ "24cs04", (kernel_ulong_t)&at24_data_24cs04 },
{ "24c08", (kernel_ulong_t)&at24_data_24c08 },
@@ -388,7 +422,7 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
struct at24_data *at24;
struct device *dev;
char *buf = val;
- int ret;
+ int i, ret;
at24 = priv;
dev = at24_base_client_dev(at24);
@@ -411,22 +445,22 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
*/
mutex_lock(&at24->lock);
- while (count) {
- ret = at24_regmap_read(at24, buf, off, count);
+ for (i = 0; count; i += ret, count -= ret) {
+ ret = at24_regmap_read(at24, buf + i, off + i, count);
if (ret < 0) {
mutex_unlock(&at24->lock);
pm_runtime_put(dev);
return ret;
}
- buf += ret;
- off += ret;
- count -= ret;
}
mutex_unlock(&at24->lock);
pm_runtime_put(dev);
+ if (unlikely(at24->read_post))
+ at24->read_post(off, buf, i);
+
return 0;
}
@@ -654,6 +688,7 @@ static int at24_probe(struct i2c_client *client)
at24->byte_len = byte_len;
at24->page_size = page_size;
at24->flags = flags;
+ at24->read_post = cdata->read_post;
at24->num_addresses = num_addresses;
at24->offset_adj = at24_get_offset_adj(flags, byte_len);
at24->client[0].client = client;
@@ -678,8 +713,30 @@ static int at24_probe(struct i2c_client *client)
return err;
}
- nvmem_config.name = dev_name(dev);
+ /*
+ * If the 'label' property is not present for the AT24 EEPROM,
+ * then nvmem_config.id is initialised to NVMEM_DEVID_AUTO,
+ * and this will append the 'devid' to the name of the NVMEM
+ * device. This is purely legacy and the AT24 driver has always
+ * defaulted to this. However, if the 'label' property is
+ * present then this means that the name is specified by the
+ * firmware and this name should be used verbatim and so it is
+ * not necessary to append the 'devid'.
+ */
+ if (device_property_present(dev, "label")) {
+ nvmem_config.id = NVMEM_DEVID_NONE;
+ err = device_property_read_string(dev, "label",
+ &nvmem_config.name);
+ if (err)
+ return err;
+ } else {
+ nvmem_config.id = NVMEM_DEVID_AUTO;
+ nvmem_config.name = dev_name(dev);
+ }
+
+ nvmem_config.type = NVMEM_TYPE_EEPROM;
nvmem_config.dev = dev;
+ nvmem_config.id = NVMEM_DEVID_AUTO;
nvmem_config.read_only = !writable;
nvmem_config.root_only = !(flags & AT24_FLAG_IRUGO);
nvmem_config.owner = THIS_MODULE;