Consult the i2c_adapter.quirks table for
the maximum read/write data length per bus
transaction. Do not exceed this transaction
limit.
Cc: Jean Delvare <jdelvare@xxxxxxx>
Cc: Alexander Deucher <Alexander.Deucher@xxxxxxx>
Cc: Andrey Grodzovsky <Andrey.Grodzovsky@xxxxxxx>
Cc: Lijo Lazar <Lijo.Lazar@xxxxxxx>
Cc: Stanley Yang <Stanley.Yang@xxxxxxx>
Cc: Hawking Zhang <Hawking.Zhang@xxxxxxx>
Signed-off-by: Luben Tuikov <luben.tuikov@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c | 80 +++++++++++++++++-----
1 file changed, 64 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
index 7fdb5bd2fc8bc8..94aeda1c7f8ca0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
@@ -32,20 +32,9 @@
#define EEPROM_OFFSET_SIZE 2
-/**
- * amdgpu_eeprom_xfer -- Read/write from/to an I2C EEPROM device
- * @i2c_adap: pointer to the I2C adapter to use
- * @slave_addr: I2C address of the slave device
- * @eeprom_addr: EEPROM address from which to read/write
- * @eeprom_buf: pointer to data buffer to read into/write from
- * @buf_size: the size of @eeprom_buf
- * @read: True if reading from the EEPROM, false if writing
- *
- * Returns the number of bytes read/written; -errno on error.
- */
-int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap,
- u16 slave_addr, u16 eeprom_addr,
- u8 *eeprom_buf, u16 buf_size, bool read)
+static int __amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap,
+ u16 slave_addr, u16 eeprom_addr,
+ u8 *eeprom_buf, u16 buf_size, bool read)
{
u8 eeprom_offset_buf[EEPROM_OFFSET_SIZE];
struct i2c_msg msgs[] = {
@@ -65,8 +54,8 @@ int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap,
u16 len;
r = 0;
- for (len = 0; buf_size > 0;
- buf_size -= len, eeprom_addr += len, eeprom_buf += len) {
+ for ( ; buf_size > 0;
+ buf_size -= len, eeprom_addr += len, eeprom_buf += len) {
/* Set the EEPROM address we want to write to/read from.
*/
msgs[0].buf[0] = (eeprom_addr >> 8) & 0xff;
@@ -120,3 +109,62 @@ int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap,
return r < 0 ? r : eeprom_buf - p;
}
+
+/**
+ * amdgpu_eeprom_xfer -- Read/write from/to an I2C EEPROM device
+ * @i2c_adap: pointer to the I2C adapter to use
+ * @slave_addr: I2C address of the slave device
+ * @eeprom_addr: EEPROM address from which to read/write
+ * @eeprom_buf: pointer to data buffer to read into/write from
+ * @buf_size: the size of @eeprom_buf
+ * @read: True if reading from the EEPROM, false if writing
+ *
+ * Returns the number of bytes read/written; -errno on error.
+ */
+int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap,
+ u16 slave_addr, u16 eeprom_addr,
+ u8 *eeprom_buf, u16 buf_size, bool read)
+{
+ const struct i2c_adapter_quirks *quirks = i2c_adap->quirks;
+ u16 limit;
+
+ if (!quirks)
+ limit = 0;
+ else if (read)
+ limit = quirks->max_read_len;
+ else
+ limit = quirks->max_write_len;
+
+ if (limit == 0) {
+ return __amdgpu_eeprom_xfer(i2c_adap, slave_addr, eeprom_addr,
+ eeprom_buf, buf_size, read);
+ } else if (limit <= EEPROM_OFFSET_SIZE) {
+ dev_err_ratelimited(&i2c_adap->dev,
+ "maddr:0x%04X size:0x%02X:quirk max_%s_len must be > %d",
+ eeprom_addr, buf_size,
+ read ? "read" : "write", EEPROM_OFFSET_SIZE);
+ return -EINVAL;
+ } else {
+ u16 ps; /* Partial size */
+ int res = 0, r;
+
+ /* The "limit" includes all data bytes sent/received,
+ * which would include the EEPROM_OFFSET_SIZE bytes.
+ * Account for them here.
+ */
+ limit -= EEPROM_OFFSET_SIZE;
+ for ( ; buf_size > 0;
+ buf_size -= ps, eeprom_addr += ps, eeprom_buf += ps) {
+ ps = min(limit, buf_size);
+
+ r = __amdgpu_eeprom_xfer(i2c_adap,
+ slave_addr, eeprom_addr,
+ eeprom_buf, ps, read);
+ if (r < 0)
+ return r;
+ res += r;
+ }
+
+ return res;
+ }
+}
--
2.32.0
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