board: ti: common: board_detect: Fix EEPROM read quirk
There are three different kinds of EEPROM possibly present on boards.
1. 1byte address. For those we should avoid 2byte address in order
not to rewrite the data. Second byte of the address can potentially
be interpreted as the data to write.
2. 2byte address with defined behaviour. When we try to use 1byte
address they just return "FF FF FF FF ... FF"
3. 2byte address with undefined behaviour (for instance, 24LC32AI).
When we try to use 1byte address, then their internal read
pointer is changed to some value. Subsequential reads may be
broken.
To gracefully handle both case #1 and case #3 we read all required
data from EEPROM at once (about 80 bytes). So either all the data is
valid or we fallback to 2byte address.
Cc: Nishanth Menon <nm@ti.com>
Fixes: a58147c2dbbf ("board: ti: common: board_detect: Do 1byte address checks first.")
Reference: https://lore.kernel.org/all/CAJs94Ebdd4foOjhGFu9Bop0v=B1US9neDLxfhgcY23ukgLzFOQ@mail.gmail.com/
Signed-off-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
Acked-by: Nishanth Menon <nm@ti.com>
diff --git a/board/ti/common/board_detect.c b/board/ti/common/board_detect.c
index ed34991..9fa7b7b 100644
--- a/board/ti/common/board_detect.c
+++ b/board/ti/common/board_detect.c
@@ -86,7 +86,6 @@
static int __maybe_unused ti_i2c_eeprom_get(int bus_addr, int dev_addr,
u32 header, u32 size, uint8_t *ep)
{
- u32 hdr_read = 0xdeadbeef;
int rc;
#if CONFIG_IS_ENABLED(DM_I2C)
@@ -113,10 +112,10 @@
* We must allow for fall through to check the data if 2 byte
* addressing works
*/
- (void)dm_i2c_read(dev, 0, (uint8_t *)&hdr_read, 4);
+ (void)dm_i2c_read(dev, 0, ep, size);
/* Corrupted data??? */
- if (hdr_read != header) {
+ if (*((u32 *)ep) != header) {
/*
* read the eeprom header using i2c again, but use only a
* 2 byte address (some newer boards need this..)
@@ -125,16 +124,12 @@
if (rc)
return rc;
- rc = dm_i2c_read(dev, 0, (uint8_t *)&hdr_read, 4);
+ rc = dm_i2c_read(dev, 0, ep, size);
if (rc)
return rc;
}
- if (hdr_read != header)
+ if (*((u32 *)ep) != header)
return -1;
-
- rc = dm_i2c_read(dev, 0, ep, size);
- if (rc)
- return rc;
#else
u32 byte;
@@ -154,26 +149,21 @@
* We must allow for fall through to check the data if 2 byte
* addressing works
*/
- (void)i2c_read(dev_addr, 0x0, byte, (uint8_t *)&hdr_read, 4);
+ (void)i2c_read(dev_addr, 0x0, byte, ep, size);
/* Corrupted data??? */
- if (hdr_read != header) {
+ if (*((u32 *)ep) != header) {
/*
* read the eeprom header using i2c again, but use only a
* 2 byte address (some newer boards need this..)
*/
byte = 2;
- rc = i2c_read(dev_addr, 0x0, byte, (uint8_t *)&hdr_read,
- 4);
+ rc = i2c_read(dev_addr, 0x0, byte, ep, size);
if (rc)
return rc;
}
- if (hdr_read != header)
+ if (*((u32 *)ep) != header)
return -1;
-
- rc = i2c_read(dev_addr, 0x0, byte, ep, size);
- if (rc)
- return rc;
#endif
return 0;
}