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device/smbus: Add i2c_eeprom_read

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Expose the existing i2c block read functionality usually used in
romstage to the smbus_bus_operations for use in ramstage.

This allows faster reading of I2C EEPROM in ramstage.

TEST=Can read I2C EEPROM on Lenovo X220 using I2C block read.

Change-Id: I1264f17317c3095f9661b0ab6aa3124a00ce86c5
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/91028
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Alicja Michalska <ahplka19@gmail.com>
This commit is contained in:
Patrick Rudolph 2026-01-31 07:23:55 +01:00 • committed by Matt DeVillier
commit c242193ca4
3 changed files with 27 additions and 4 deletions
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8
src/device/smbus_ops.c
View file

@ -35,3 +35,11 @@ int smbus_block_write(struct device *dev, u8 cmd, u8 bytes, const u8 *buffer)
return ops_smbus_bus(get_pbus_smbus(dev))->block_write(dev, cmd,
bytes, buffer);
}
int smbus_i2c_eeprom_read(struct device *dev, u8 cmd, u8 bytes, u8 *buffer)
{
CHECK_PRESENCE(i2c_eeprom_read);
return ops_smbus_bus(get_pbus_smbus(dev))->i2c_eeprom_read(dev, cmd,
bytes, buffer);
}

2
src/include/device/smbus.h
View file

@ -16,6 +16,7 @@ struct smbus_bus_operations {
int (*block_read)(struct device *dev, u8 cmd, u8 bytes, u8 *buffer);
int (*block_write)(struct device *dev, u8 cmd, u8 bytes,
const u8 *buffer);
int (*i2c_eeprom_read)(struct device *dev, u8 offset, u8 bytes, u8 *buffer);
};
static inline const struct smbus_bus_operations *ops_smbus_bus(struct bus *bus)
@ -54,6 +55,7 @@ static inline int smbus_write_byte(struct device *const dev, u8 addr, u8 val)
int smbus_block_read(struct device *dev, u8 cmd, u8 bytes, u8 *buffer);
int smbus_block_write(struct device *dev, u8 cmd, u8 bytes, const u8 *buffer);
int smbus_i2c_eeprom_read(struct device *dev, u8 cmd, u8 bytes, u8 *buffer);
#endif
#endif /* DEVICE_SMBUS_H */

21
src/southbridge/intel/common/smbus_ops.c
View file

@ -56,11 +56,24 @@ static int lsmbus_block_read(struct device *dev, u8 cmd, u8 bytes, u8 *buf)
return do_smbus_block_read(res->base, device, cmd, bytes, buf);
}
static int lsmbus_i2c_eeprom_read(struct device *dev, u8 offset, u8 bytes, u8 *buf)
{
u16 device;
struct resource *res;
struct bus *pbus;
device = dev->path.i2c.device;
pbus = get_pbus_smbus(dev);
res = find_resource(pbus->dev, PCI_BASE_ADDRESS_4);
return do_i2c_eeprom_read(res->base, device, offset, bytes, buf);
}
struct smbus_bus_operations lops_smbus_bus = {
.read_byte = lsmbus_read_byte,
.write_byte = lsmbus_write_byte,
.block_read = lsmbus_block_read,
.block_write = lsmbus_block_write,
.read_byte = lsmbus_read_byte,
.write_byte = lsmbus_write_byte,
.block_read = lsmbus_block_read,
.block_write = lsmbus_block_write,
.i2c_eeprom_read = lsmbus_i2c_eeprom_read,
};
void smbus_read_resources(struct device *dev)