Commit 42cd0ab4 authored by Yicheng Li's avatar Yicheng Li Committed by Enric Balletbo i Serra
Browse files

platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW 



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.

Signed-off-by: default avatarYicheng Li <yichengli@chromium.org>
Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: default avatarGwendal Grignou <gwendal@chromium.org>
Signed-off-by: default avatarEnric Balletbo i Serra <enric.balletbo@collabora.com>
parent 8673e944

drivers/platform/chrome/cros_ec.c

+30 −0
Original line number Diff line number Diff line
@@ -138,6 +138,24 @@ 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.
@@ -237,6 +255,18 @@ int cros_ec_register(struct cros_ec_device *ec_dev) 
		dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",

			err);



	if (ec_dev->mkbp_event_supported) {

		/*

		 * 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;

include/linux/platform_data/cros_ec_proto.h

+4 −0
Original line number Diff line number Diff line
@@ -125,6 +125,9 @@ struct cros_ec_command { 
 * @host_event_wake_mask: Mask of host events that cause wake from suspend.

 * @last_event_time: exact time from the hard irq when we got notified of

 *     a new event.

 * @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
@@ -166,6 +169,7 @@ struct cros_ec_device { 
	u32 host_event_wake_mask;

	u32 last_resume_result;

	ktime_t last_event_time;

	struct notifier_block notifier_ready;



	/* The platform devices used by the mfd driver */

	struct platform_device *ec;

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