diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/ec/google/chromeec/ec_mec.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/src/ec/google/chromeec/ec_mec.c b/src/ec/google/chromeec/ec_mec.c index 9836edad67..264a256036 100644 --- a/src/ec/google/chromeec/ec_mec.c +++ b/src/ec/google/chromeec/ec_mec.c @@ -76,12 +76,22 @@ void mec_io_bytes(int write, u16 port, unsigned int length, u8 *buf, u8 *csum) { int i = 0; int io_addr; + u8 access_mode, new_access_mode; if (length == 0) return; + /* + * Long access cannot be used on misaligned data since reading B0 loads + * the data register and writing B3 flushes it. + */ + if (port & 0x3) + access_mode = ACCESS_TYPE_BYTE; + else + access_mode = ACCESS_TYPE_LONG_AUTO_INCREMENT; + /* Initialize I/O at desired address */ - mec_emi_write_address(port, ACCESS_TYPE_LONG_AUTO_INCREMENT); + mec_emi_write_address(port, access_mode); /* Skip bytes in case of misaligned port */ io_addr = MEC_EMI_EC_DATA_B0 + (port & 0x3); @@ -94,11 +104,26 @@ void mec_io_bytes(int write, u16 port, unsigned int length, u8 *buf, u8 *csum) if (csum) *csum += buf[i]; + port++; /* Extra bounds check in case of misaligned length */ if (++i == length) return; } + /* + * Use long auto-increment access except for misaligned write, + * since writing B3 triggers the flush. + */ + if (length - i < 4 && write) + new_access_mode = ACCESS_TYPE_BYTE; + else + new_access_mode = ACCESS_TYPE_LONG_AUTO_INCREMENT; + if (new_access_mode != access_mode || + access_mode != ACCESS_TYPE_LONG_AUTO_INCREMENT) { + access_mode = new_access_mode; + mec_emi_write_address(port, access_mode); + } + /* Access [B0, B3] on each loop pass */ io_addr = MEC_EMI_EC_DATA_B0; } |