Fix I2C access code

While the current implementation works for what it is actually used, it
is broken when trying to do larger transfers.

The length field in the control register has a size of 4 bits. In every
transfer, length+1 bytes are read. Thus, each transfer is limited to a
maximum of 16 bytes. Add a check for the length, and write the correct
value to the register.

Also update the loop in "sfp_send_data" to properly increment the output
register. Remove the unused special case for a length of 128 bytes.
This commit is contained in:
Jan Hoffmann
2026-03-28 18:14:15 +01:00
parent df498b0879
commit efe0c282ba
2 changed files with 11 additions and 10 deletions
+9 -8
View File
@@ -175,11 +175,15 @@ void send_sfp_info(uint8_t sfp)
void sfp_send_data(uint8_t slot, uint8_t reg, uint8_t len)
{
// maximum supported transfer size is 16 bytes
if (len > 16)
return;
if (reg & 0x80) { // Configure SFP readings address (0x51) as I2C device address
reg &= 0x7f;
REG_WRITE(RTL837X_REG_I2C_CTRL, 0x00, 0x1 << (I2C_MEM_ADDR_WIDTH-16) | len & 0xf, 0x51 >> 5, (0x51 << 3) & 0xff);
REG_WRITE(RTL837X_REG_I2C_CTRL, 0x00, 0x1 << (I2C_MEM_ADDR_WIDTH-16) | (len - 1) & 0xf, 0x51 >> 5, (0x51 << 3) & 0xff);
} else {
REG_WRITE(RTL837X_REG_I2C_CTRL, 0x00, 0x1 << (I2C_MEM_ADDR_WIDTH-16) | len & 0xf, 0x50 >> 5, (0x50 << 3) & 0xff);
REG_WRITE(RTL837X_REG_I2C_CTRL, 0x00, 0x1 << (I2C_MEM_ADDR_WIDTH-16) | (len - 1) & 0xf, 0x50 >> 5, (0x50 << 3) & 0xff);
}
reg_read_m(RTL837X_REG_I2C_CTRL);
@@ -196,13 +200,10 @@ void sfp_send_data(uint8_t slot, uint8_t reg, uint8_t len)
reg_read_m(RTL837X_REG_I2C_CTRL);
} while (sfr_data[3] & 0x1);
for (uint8_t i = 0; i < len & 0xf; i++) {
for (uint8_t i = 0; i < len; i++) {
if (!(i & 0x3))
reg_read_m(RTL837X_REG_I2C_OUT + (i >> 2));
if (len & 0x80)
char_to_html(sfr_data[3 - (i & 0x3)]);
else
byte_to_html(sfr_data[3 - (i & 0x3)]);
reg_read_m(RTL837X_REG_I2C_OUT + i);
byte_to_html(sfr_data[3 - (i & 0x3)]);
}
}