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

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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.

Signed-off-by: Yicheng Li <yichengli@chromium.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
This commit is contained in:
Yicheng Li 2020-02-03 14:53:56 -08:00 • committed by Enric Balletbo i Serra
parent 8673e944b5
commit 42cd0ab476
2 changed files with 34 additions and 0 deletions
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30
drivers/platform/chrome/cros_ec.c
View file

@ -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;

4
include/linux/platform_data/cros_ec_proto.h
View file

@ -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;