Messages in this thread | | | From | Guenter Roeck <> | Date | Thu, 14 Jul 2022 09:31:25 -0700 | Subject | Re: [PATCH] platform/chrome: cros_ec_proto: Update version on GET_NEXT_EVENT failure |
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On Thu, Jul 14, 2022 at 9:09 AM Patryk Duda <pdk@semihalf.com> wrote: > > Some EC based devices (e.g. Fingerpint MCU) can jump to RO part of the > firmware (intentionally or due to device reboot). The RO part doesn't > change during the device lifecycle, so it won't support newer version > of EC_CMD_GET_NEXT_EVENT command. > > Function cros_ec_query_all() is responsible for finding maximum > supported MKBP event version. It's usually called when the device is > running RW part of the firmware, so the command version can be > potentially higher than version supported by the RO. > > The problem was fixed by updating maximum supported version when the > device returns EC_RES_INVALID_VERSION (mapped to -ENOPROTOOPT). That way > the kernel will use highest common version supported by RO and RW. > > Fixes: 3300fdd630d4 ("platform/chrome: cros_ec: handle MKBP more events flag") > Cc: <stable@vger.kernel.org> # 5.10+ > Signed-off-by: Patryk Duda <pdk@semihalf.com>
Nice catch. That may explain some hung task issues. observed in EC_CMD_GET_NEXT_EVENT handling
Reviewed-by: Guenter Roeck <groeck@chromium.org>
> --- > When Fingerprint MCU is rebooted (e.g. as a part of tests) it jumps to > the RO image and performs RW image signature check. If kernel calls > EC_CMD_GET_NEXT_EVENT FPMCU RO will respond with EC_RES_INVALID_VERSION > because it's older than RW and supports up to version 1 of the command. > As a result kernel keeps trying to get MKBP events and effectively > blocks FPMCU from jumping to RW image. > > Before patch 3300fdd630d4 the driver called version 1 of the command. > If the device responded with EC_RES_INVALID_VERSION, the driver would > use version 0 of the command. > > Best regards, > Patryk > > drivers/platform/chrome/cros_ec_proto.c | 32 +++++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > > diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c > index ff767dccdf0f6..0a131045d50a9 100644 > --- a/drivers/platform/chrome/cros_ec_proto.c > +++ b/drivers/platform/chrome/cros_ec_proto.c > @@ -750,6 +750,7 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, > u8 event_type; > u32 host_event; > int ret; > + u32 ver_mask = 0; > > /* > * Default value for wake_event. > @@ -771,6 +772,37 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, > return get_keyboard_state_event(ec_dev); > > ret = get_next_event(ec_dev); > + /* > + * -ENOPROTOOPT is returned when EC returns EC_RES_INVALID_VERSION. > + * This can occur when EC based device (e.g. Fingerprint MCU) jumps to > + * the RO image which doesn't support newer version of the command. In > + * this case we will attempt to update maximum supported version of the > + * EC_CMD_GET_NEXT_EVENT. > + */ > + if (ret == -ENOPROTOOPT) { > + dev_dbg(ec_dev->dev, > + "GET_NEXT_EVENT returned invalid version error.\n"); > + ret = cros_ec_get_host_command_version_mask(ec_dev, > + EC_CMD_GET_NEXT_EVENT, > + &ver_mask); > + if (ret < 0 || ver_mask == 0) > + /* > + * Do not change the MKBP supported version if we can't > + * obtain supported version correctly. Please note that > + * calling EC_CMD_GET_NEXT_EVENT returned > + * EC_RES_INVALID_VERSION which means that the command > + * is present. > + */ > + return -ENOPROTOOPT; > + > + ec_dev->mkbp_event_supported = fls(ver_mask); > + dev_dbg(ec_dev->dev, "MKBP support version changed to %u\n", > + ec_dev->mkbp_event_supported - 1); > + > + /* Try to get next event with new MKBP support version set. */ > + ret = get_next_event(ec_dev); > + } > + > if (ret <= 0) > return ret; > > -- > 2.31.0 >
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