diff options
| -rw-r--r-- | board/snow/board.c | 71 | ||||
| -rw-r--r-- | chip/stm32/i2c.c | 8 |
2 files changed, 71 insertions, 8 deletions
diff --git a/board/snow/board.c b/board/snow/board.c index 4c9e30bd4b..4231ee4b2a 100644 --- a/board/snow/board.c +++ b/board/snow/board.c @@ -5,12 +5,15 @@ /* Snow board-specific configuration */ #include "board.h" +#include "chipset.h" #include "common.h" +#include "console.h" #include "dma.h" #include "gpio.h" #include "i2c.h" #include "registers.h" #include "spi.h" +#include "timer.h" #include "util.h" #define GPIO_KB_INPUT (GPIO_INPUT | GPIO_PULL_UP | GPIO_INT_BOTH) @@ -170,3 +173,71 @@ void board_interrupt_host(int active) /* interrupt host by using active low EC_INT signal */ gpio_set_level(GPIO_EC_INT, !active); } + +enum { + /* Time between requesting bus and deciding that we have it */ + BUS_SLEW_DELAY_US = 10, + + /* Time between retrying to see if the AP has released the bus */ + BUS_WAIT_RETRY_US = 3000, + + /* Time to wait until the bus becomes free */ + BUS_WAIT_FREE_US = 50 * 1000, +}; + +#ifdef CONFIG_ARBITRATE_I2C +#define GPIO_AP_CLAIM GPIO_SPI1_NSS +#define GPIO_EC_CLAIM GPIO_SPI1_MISO + +int board_i2c_claim(int port) +{ + timestamp_t start; + + if (port != I2C_PORT_HOST) + return EC_SUCCESS; + + /* If AP is off, we have the bus */ + if (!chipset_in_state(CHIPSET_STATE_ON)) { + gpio_set_level(GPIO_EC_CLAIM, 0); + return EC_SUCCESS; + } + + /* Start a round of trying to claim the bus */ + start = get_time(); + do { + timestamp_t start_retry; + int waiting = 0; + + /* Indicate that we want to claim the bus */ + gpio_set_level(GPIO_EC_CLAIM, 0); + usleep(BUS_SLEW_DELAY_US); + + /* Wait for the AP to release it */ + start_retry = get_time(); + while (time_since32(start_retry) < BUS_WAIT_RETRY_US) { + if (gpio_get_level(GPIO_AP_CLAIM)) { + /* We got it, so return */ + return EC_SUCCESS; + } + + if (!waiting) + waiting = 1; + } + + /* It didn't release, so give up, wait, and try again */ + gpio_set_level(GPIO_EC_CLAIM, 1); + + usleep(BUS_WAIT_RETRY_US); + } while (time_since32(start) < BUS_WAIT_FREE_US); + + return EC_ERROR_BUSY; +} + +void board_i2c_release(int port) +{ + if (port == I2C_PORT_HOST) { + /* Release our claim */ + gpio_set_level(GPIO_EC_CLAIM, 1); + } +} +#endif diff --git a/chip/stm32/i2c.c b/chip/stm32/i2c.c index e4840e786e..ec3be2ace7 100644 --- a/chip/stm32/i2c.c +++ b/chip/stm32/i2c.c @@ -424,10 +424,6 @@ static int i2c_master_transmit(int port, int slave_addr, uint8_t *data, { int rv, i; - /* if the AP is ON, don't play with the connection */ - if ((port == I2C_PORT_SLAVE) && chipset_in_state(CHIPSET_STATE_ON)) - return EC_ERROR_BUSY; - disable_ack(port); rv = master_start(port, slave_addr); if (rv) @@ -471,10 +467,6 @@ static int i2c_master_receive(int port, int slave_addr, uint8_t *data, */ int rv, i; - /* if the AP is ON, don't play with the connection */ - if ((port == I2C_PORT_SLAVE) && chipset_in_state(CHIPSET_STATE_ON)) - return EC_ERROR_BUSY; - if (data == NULL || size < 1) return EC_ERROR_INVAL; |