diff options
Diffstat (limited to 'board/cr50/board.c')
| -rw-r--r-- | board/cr50/board.c | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/board/cr50/board.c b/board/cr50/board.c index 67908dc388..e7e19a4577 100644 --- a/board/cr50/board.c +++ b/board/cr50/board.c @@ -1206,8 +1206,10 @@ static int get_strap_config(uint8_t *config) enum strap_list s0; int lvl; int flags; - uint8_t pull_a; - uint8_t pull_b; + uint8_t use_i2c; + uint8_t i2c_prop; + uint8_t use_spi; + uint8_t spi_prop; /* * There are 4 pins that are used to determine Cr50 board strapping @@ -1313,13 +1315,37 @@ static int get_strap_config(uint8_t *config) * config table entries. */ - pull_a = *config & 0xa0; - pull_b = *config & 0xa; - if ((!pull_a && !pull_b) || (pull_a && pull_b)) + use_i2c = *config & 0xa0; + use_spi = *config & 0x0a; + /* + * The strap signals should have at least one pullup. Nothing can + * interfere with these. If we did not read any pullups, these are + * invalid straps. The config can't be salvaged. + */ + if (!use_i2c && !use_spi) return EC_ERROR_INVAL; + /* + * The unused strap signals are used for the bus to the AP. If the AP + * has added pullups to the signals, it could interfere with the strap + * readings. If pullups are found on both the SPI and I2C straps, use + * the board properties to determine SPI vs I2C. We can use this to mask + * unused config pins the AP is interfering with. + */ + if (use_i2c && use_spi) { + spi_prop = (GREG32(PMU, LONG_LIFE_SCRATCH1) & + BOARD_SLAVE_CONFIG_SPI); + i2c_prop = (GREG32(PMU, LONG_LIFE_SCRATCH1) & + BOARD_SLAVE_CONFIG_I2C); + /* Make sure exactly one interface is selected */ + if ((i2c_prop && spi_prop) || (!spi_prop && !i2c_prop)) + return EC_ERROR_INVAL; + use_spi = spi_prop; + CPRINTS("Ambiguous strap config. Use %s based on old " + "brdprop.", use_spi ? "spi" : "i2c"); + } /* Now that I2C vs SPI is known, mask the unused strap bits. */ - *config &= *config & 0xa ? 0xf : 0xf0; + *config &= use_spi ? 0xf : 0xf0; return EC_SUCCESS; } |