Messages in this thread Patch in this message |  | | From | Yicheng Li <> | Subject | [PATCH v5] platform: cros_ec: Query EC protocol version if EC transitions between RO/RW | Date | Tue, 7 Jan 2020 14:06:40 -0800 |
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RO and RW of EC may have different EC protocol version. If EC transitions between RO and RW, but AP does not reboot (this is true for fingerprint microcontroller / cros_fp, but not true for main ec / cros_ec), the AP still uses the protocol version queried before transition, which can cause problems. In the case of fingerprint microcontroller, this causes AP to send the wrong version of EC_CMD_GET_NEXT_EVENT to RO in the interrupt handler, which in turn prevents RO to clear the interrupt line to AP, in an infinite loop.
Once an EC_HOST_EVENT_INTERFACE_READY is received, we know that there might have been a transition between RO and RW, so re-query the protocol.
Change-Id: I49a51cc10d22a4ab9e75204a4c0c8819d5b3d282 Signed-off-by: Yicheng Li <yichengli@chromium.org> --- drivers/platform/chrome/cros_ec.c | 24 +++++++++++++++++++++ include/linux/platform_data/cros_ec_proto.h | 3 +++ 2 files changed, 27 insertions(+)
diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c index 9b2d07422e17..38ec1fb409a5 100644 --- a/drivers/platform/chrome/cros_ec.c +++ b/drivers/platform/chrome/cros_ec.c @@ -104,6 +104,23 @@ static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event) return ret; } +static int cros_ec_ready_event(struct notifier_block *nb, + unsigned long queued_during_suspend, void *_notify) +{ + struct cros_ec_device *ec_dev = container_of(nb, struct cros_ec_device, + notifier_ready); + u32 host_event = cros_ec_get_host_event(ec_dev); + + if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_INTERFACE_READY)) { + mutex_lock(&ec_dev->lock); + cros_ec_query_all(ec_dev); + mutex_unlock(&ec_dev->lock); + return NOTIFY_OK; + } + + return NOTIFY_DONE; +} + /** * cros_ec_register() - Register a new ChromeOS EC, using the provided info. * @ec_dev: Device to register. @@ -201,6 +218,13 @@ int cros_ec_register(struct cros_ec_device *ec_dev) dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec", err); + /* Register the notifier for EC_HOST_EVENT_INTERFACE_READY event. */ + ec_dev->notifier_ready.notifier_call = cros_ec_ready_event; + err = blocking_notifier_chain_register(&ec_dev->event_notifier, + &ec_dev->notifier_ready); + if (err) + return err; + dev_info(dev, "Chrome EC device registered\n"); return 0; diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h index 0d4e4aaed37a..a1c545c464e7 100644 --- a/include/linux/platform_data/cros_ec_proto.h +++ b/include/linux/platform_data/cros_ec_proto.h @@ -121,6 +121,8 @@ struct cros_ec_command { * @event_data: Raw payload transferred with the MKBP event. * @event_size: Size in bytes of the event data. * @host_event_wake_mask: Mask of host events that cause wake from suspend. + * @notifier_ready: The notifier_block to let the kernel re-query EC + * communication protocol when the EC sends EC_HOST_EVENT_INTERFACE_READY. * @ec: The platform_device used by the mfd driver to interface with the * main EC. * @pd: The platform_device used by the mfd driver to interface with the @@ -161,6 +163,7 @@ struct cros_ec_device { int event_size; u32 host_event_wake_mask; u32 last_resume_result; + struct notifier_block notifier_ready; /* The platform devices used by the mfd driver */ struct platform_device *ec; -- 2.21.0
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