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authorDaisuke Nojiri <dnojiri@chromium.org>2018-04-26 12:59:58 -0700
committerPatrick Georgi <pgeorgi@google.com>2018-04-30 06:27:24 +0000
commitccfa18feff26211631be53fe1db1b8b0b534cd79 (patch)
tree45ea7f928c6931d8b8c9cfa7804ab1cb3418fa89 /src/ec/google
parentc01a9ab56244dbb6d93e3be128ef1fadccc9ed2b (diff)
downloadcoreboot-ccfa18feff26211631be53fe1db1b8b0b534cd79.tar.xz
cros-ec: Avoid infinitely looping in google_chromeec_pd_get_amode
Currently, google_chromeec_pd_get_amode infinitely loops if a TCPC port is connected to a device with alternate mode(s) and the call is made for the mode with the index higher than 0 (e.g. Zinger). Cros EC manages alternative modes entered in an array (amode[]). The command is designed to accept a query for an particular index and a particular SVID. Zinger has a 'Google' mode. It's stored in amode[0]. When AP queries first time for DisplayPort with index=0, EC says 'no' as expected. AP sends the next query with index=1 but EC_CMD_PROTO_VERSION (0x00) is sent instead because cmd_code is cleared by google_chromeec_command. res.svid is supposed to be 0 when EC hits the last index + 1 but res.svid is set to 2 by the EC_CMD_PROTO_VERSION handler because EC_PROTO_VERSION is currently 2. So, the call succeeds and AP goes to the next index and this repeats forever. Any USB-C device with non-DisplayPort alternate mode can cause this hang unless HDMI port is used. This patch resets all the fields of chromeec_command in each iteration in case google_chromeec_command changes them. BUG=b:78630899 BRANCH=none TEST=Verify Fizz boots without monitors on Zinger. Verify the svid enumeration happens as expected. Change-Id: I388ed4bdfac9176d8e690c429e99674ed267004f Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org> Reviewed-on: https://review.coreboot.org/25878 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org> Reviewed-by: Furquan Shaikh <furquan@google.com>
Diffstat (limited to 'src/ec/google')
-rw-r--r--src/ec/google/chromeec/ec.c25
1 files changed, 14 insertions, 11 deletions
diff --git a/src/ec/google/chromeec/ec.c b/src/ec/google/chromeec/ec.c
index fb3ffab181..5ce3f68823 100644
--- a/src/ec/google/chromeec/ec.c
+++ b/src/ec/google/chromeec/ec.c
@@ -963,23 +963,26 @@ int google_chromeec_pd_get_amode(uint16_t svid)
for (i = 0; i < r.num_ports; i++) {
struct ec_params_usb_pd_get_mode_request p;
struct ec_params_usb_pd_get_mode_response res;
-
- p.port = i;
- p.svid_idx = 0;
- cmd.cmd_code = EC_CMD_USB_PD_GET_AMODE;
- cmd.cmd_version = 0;
- cmd.cmd_data_in = &p;
- cmd.cmd_size_in = sizeof(p);
- cmd.cmd_data_out = &res;
- cmd.cmd_size_out = sizeof(res);
- cmd.cmd_dev_index = 0;
+ int svid_idx = 0;
do {
+ /* Reset cmd in each iteration in case
+ google_chromeec_command changes it. */
+ p.port = i;
+ p.svid_idx = svid_idx;
+ cmd.cmd_code = EC_CMD_USB_PD_GET_AMODE;
+ cmd.cmd_version = 0;
+ cmd.cmd_data_in = &p;
+ cmd.cmd_size_in = sizeof(p);
+ cmd.cmd_data_out = &res;
+ cmd.cmd_size_out = sizeof(res);
+ cmd.cmd_dev_index = 0;
+
if (google_chromeec_command(&cmd) < 0)
return -1;
if (res.svid == svid)
return 1;
- p.svid_idx++;
+ svid_idx++;
} while (res.svid);
}