From 776658d8a23911d3123742008fd4ba1e9b33665e Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Tue, 12 Aug 2014 22:52:00 -0500 Subject: stfm32f0: always send bytes over i2c for EC command responses Certain i2c host drivers don't allow one to snoop the byte stream to abort a transaction. Allow those devices to make forward progress by sending out the '0xec' byte for any requests coming through after an EC host command error. BUG=chrome-os-partner:30784 BRANCH=None TEST=Ran on ryu. Allowed passthru probing which normally hung the system because of there not being a passthrue device on ryu -- error returned. Instead the command returns successfully by returning 0xec for the unfilled bytes. Change-Id: Ibcab5ade1f727f3852995437105eb9fa693caadf Signed-off-by: Aaron Durbin Reviewed-on: https://chromium-review.googlesource.com/212165 Reviewed-by: Alec Berg Reviewed-by: Randall Spangler --- chip/stm32/i2c-stm32f0.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/chip/stm32/i2c-stm32f0.c b/chip/stm32/i2c-stm32f0.c index 1a289393d4..11dd4c7ba4 100644 --- a/chip/stm32/i2c-stm32f0.c +++ b/chip/stm32/i2c-stm32f0.c @@ -153,6 +153,14 @@ static void i2c_send_response_packet(struct host_packet *pkt) /* I2C is slow, so let other things run while we wait */ usleep(50); } + + /* + * If an error occurred. Set the transmitter not full so as to keep + * sending '0xec' in the event loop. That way the master doesn't have + * to snoop the response stream. + */ + if (pkt->driver_result != EC_RES_SUCCESS) + STM32_I2C_CR1(host_i2c_resp_port) |= STM32_I2C_CR1_TXIE; } /* Process the command in the i2c host buffer */ -- cgit v1.2.1