Furquan Shaikh (furquan@google.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/16258
-gerrit
commit 35469d5699d4034df0cb305570a11d472900f7fc Author: Furquan Shaikh furquan@google.com Date: Thu Aug 18 21:39:14 2016 -0700
google/chromeec: Ensure data is ready before reading it
Before reading the data provided by EC to the host, ensure that data ready flag is set. Otherwise, it could result in reading stale/incorrect data from the data buffer.
BUG=chrome-os-partner:56395 BRANCH=None TEST=Verified that lidclose event is read correctly by host on reef.
Change-Id: I88e345d64256af8325b3dbf670467d09f09420f0 Signed-off-by: Furquan Shaikh furquan@google.com --- src/ec/google/chromeec/ec_lpc.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/src/ec/google/chromeec/ec_lpc.c b/src/ec/google/chromeec/ec_lpc.c index 06b506b..51a6e53 100644 --- a/src/ec/google/chromeec/ec_lpc.c +++ b/src/ec/google/chromeec/ec_lpc.c @@ -96,7 +96,7 @@ static inline u8 write_byte(u8 val, u16 port) return byte; }
-static int google_chromeec_wait_ready(u16 port) +static int google_chromeec_status_check(u16 port, u8 mask, u8 cond) { u8 ec_status = read_byte(port); u32 time_count = 0; @@ -108,8 +108,7 @@ static int google_chromeec_wait_ready(u16 port) */ #define MAX_EC_TIMEOUT_US 1000000
- while (ec_status & - (EC_LPC_CMDR_PENDING | EC_LPC_CMDR_BUSY)) { + while ((ec_status & mask) != cond) { udelay(1); if (time_count++ == MAX_EC_TIMEOUT_US) return -1; @@ -118,6 +117,13 @@ static int google_chromeec_wait_ready(u16 port) return 0; }
+static int google_chromeec_wait_ready(u16 port) +{ + return google_chromeec_status_check(port, + EC_LPC_CMDR_PENDING | + EC_LPC_CMDR_BUSY, 0); +} + #if CONFIG_EC_GOOGLE_CHROMEEC_ACPI_MEMMAP /* Read memmap data through ACPI port 66/62 */ static int read_memmap(u8 *data, u8 offset) @@ -481,6 +487,12 @@ struct chip_operations ec_google_chromeec_ops = {
#endif /* __SMM__ */
+static int google_chromeec_data_ready(u16 port) +{ + return google_chromeec_status_check(port, EC_LPC_CMDR_DATA, + EC_LPC_CMDR_DATA); +} + u8 google_chromeec_get_event(void) { if (google_chromeec_wait_ready(EC_LPC_ADDR_ACPI_CMD)) { @@ -496,6 +508,11 @@ u8 google_chromeec_get_event(void) return 0; }
+ if (google_chromeec_data_ready(EC_LPC_ADDR_ACPI_CMD)) { + printk(BIOS_ERR, "Timeout waiting for data ready!\n"); + return 0; + } + /* Event (or 0 if none) is returned directly in the data byte */ return read_byte(EC_LPC_ADDR_ACPI_DATA); }