From: Yicheng Li <yichengli@chromium.org>
To: linux-kernel@vger.kernel.org
Cc: bleung@chromium.org, yichengli@chromium.org,
gwendal@chromium.org, enric.balletbo@collabora.com
Subject: [PATCH v4] mfd / platform: cros_ec: Query EC protocol version if EC transitions between RO/RW
Date: Mon, 25 Nov 2019 14:15:17 -0800 [thread overview]
Message-ID: <20191125221517.91611-1-yichengli@chromium.org> (raw)
In-Reply-To: <0f223903-ec93-a5ec-e858-fa0e2e282cf3@collabora.com>
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>
---
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
next prev parent reply other threads:[~2019-11-25 22:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-22 21:29 [PATCH v2] mfd / platform: cros_ec: Query EC protocol version if EC transitions between RO/RW Yicheng Li
2019-11-25 17:09 ` Enric Balletbo i Serra
2019-11-25 22:08 ` [PATCH v3] " Yicheng Li
2019-11-25 22:15 ` Yicheng Li [this message]
2019-11-26 9:56 ` [PATCH v4] " Enric Balletbo i Serra
2019-12-03 19:20 ` Gwendal Grignou
2019-12-16 10:40 ` Lee Jones
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