Messages in this thread |  | | Subject | Re: [PATCH v6] platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW | From | Marek Szyprowski <> | Date | Tue, 4 Feb 2020 08:30:32 +0100 |
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Hi
On 03.02.2020 23:53, Yicheng Li wrote: > 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>
Works fine on Samsung Exynos-based Chromebooks: Snow, Peach-Pit and Peach-Pi.
> --- > Hi Enric and Marek, > >> This patch landed recently in linux-next as commit >> 241a69ae8ea8e2defec751fe55dac1287aa044b8. Sadly, it causes following >> kernel oops on any key press on Samsung Exynos-based Chromebooks (Snow, >> Peach-Pit and Peach-Pi): > >> Many thanks for report the issue, we will take a look ASAP and revert >> this commit meanwhile. > >> Simply removing the BUG_ON() from cros_ec_get_host_event() function >> fixes the issue, but I don't know the protocol details to judge if this >> is the correct way of fixing it. > The issue was those Samsung Chromebooks (Snow, Peach-Pit and Peach-Pi) > do not support mkbp events, yet we applied the same thing to them, which > we shouldn't. This v6 should fix it: I Just added a check > > if (ec_dev->mkbp_event_supported) > > in cros_ec_register(). > > > > drivers/platform/chrome/cros_ec.c | 29 +++++++++++++++++++++ > include/linux/platform_data/cros_ec_proto.h | 3 +++ > 2 files changed, 32 insertions(+) > > diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c > index 9b2d07422e17..f16804db805b 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 +218,18 @@ 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; > 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;
Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
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