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Date:   Fri, 21 Dec 2018 07:24:44 +0000
From:   Lee Jones <lee.jones@linaro.org>
To:     egranata@google.com
Cc:     Benson Leung <bleung@chromium.org>,
        Olof Johansson <olof@lixom.net>, linux-kernel@vger.kernel.org,
        Gwendal Grignou <gwendal@google.com>,
        Brian Norris <briannorris@google.com>,
        Enrico Granata <egranata@chromium.org>
Subject: Re: [PATCH] mfd: cros_ec: Add support for MKBP more event flags
Message-ID: <20181221072444.GM4497@dell>
References: <20181207222223.GA240898@google.com>
 <20181221002933.747-1-egranata@chromium.org>
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On Thu, 20 Dec 2018, egranata@google.com wrote:

> From: Enrico Granata <egranata@chromium.org>
> 
> The ChromeOS EC has support for signaling to the host that
> a single IRQ can serve multiple MKBP events.
> 
> Doing this serves an optimization purpose, as it minimizes the
> number of round-trips into the interrupt handling machinery, and
> it proves beneficial to sensor timestamping as it keeps the desired
> synchronization of event times between the two processors.
> 
> This patch adds kernel support for this EC feature, allowing the
> ec_irq to loop until all events have been served.
> 
> Signed-off-by: Enrico Granata <egranata@chromium.org>
> ---

What is this?

A [RESEND]?  If so, you should s/[PATCH]/[RESEND/ in the subject line.

An updated patch?  If so, you need a Changelog here and a [PATCH v2].

Also, submitting in-reply-to isn't scalable.

Please resubmit this patch.

>  drivers/mfd/cros_ec.c                   | 20 +++++++++++++--
>  drivers/platform/chrome/cros_ec_proto.c | 33 +++++++++++--------------
>  include/linux/mfd/cros_ec.h             |  7 ++++--
>  include/linux/mfd/cros_ec_commands.h    | 15 +++++++++++
>  4 files changed, 53 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
> index fe6f83766144f..17903a378aa1a 100644
> --- a/drivers/mfd/cros_ec.c
> +++ b/drivers/mfd/cros_ec.c
> @@ -51,13 +51,16 @@ static const struct mfd_cell ec_pd_cell = {
>  	.pdata_size = sizeof(pd_p),
>  };
>  
> -static irqreturn_t ec_irq_thread(int irq, void *data)
> +static bool ec_handle_event(struct cros_ec_device *ec_dev)
>  {
> -	struct cros_ec_device *ec_dev = data;
>  	bool wake_event = true;
>  	int ret;
> +	bool ec_has_more_events = false;
>  
>  	ret = cros_ec_get_next_event(ec_dev, &wake_event);
> +	if (ret > 0)
> +		ec_has_more_events =
> +			ec_dev->event_data.event_type & EC_MKBP_HAS_MORE_EVENTS;
>  
>  	/*
>  	 * Signal only if wake host events or any interrupt if
> @@ -70,6 +73,19 @@ static irqreturn_t ec_irq_thread(int irq, void *data)
>  	if (ret > 0)
>  		blocking_notifier_call_chain(&ec_dev->event_notifier,
>  					     0, ec_dev);
> +
> +	return ec_has_more_events;
> +}
> +
> +static irqreturn_t ec_irq_thread(int irq, void *data)
> +{
> +	struct cros_ec_device *ec_dev = data;
> +	bool ec_has_more_events;
> +
> +	do {
> +		ec_has_more_events = ec_handle_event(ec_dev);
> +	} while (ec_has_more_events);
> +
>  	return IRQ_HANDLED;
>  }
>  
> diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
> index b6fd4838f60f3..bb126d95b2fd4 100644
> --- a/drivers/platform/chrome/cros_ec_proto.c
> +++ b/drivers/platform/chrome/cros_ec_proto.c
> @@ -420,10 +420,14 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev)
>  	ret = cros_ec_get_host_command_version_mask(ec_dev,
>  						    EC_CMD_GET_NEXT_EVENT,
>  						    &ver_mask);
> -	if (ret < 0 || ver_mask == 0)
> +	if (ret < 0 || ver_mask == 0) {
>  		ec_dev->mkbp_event_supported = 0;
> -	else
> -		ec_dev->mkbp_event_supported = 1;
> +		dev_info(ec_dev->dev, "MKBP not supported\n");
> +	} else {
> +		ec_dev->mkbp_event_supported = fls(ver_mask);
> +		dev_info(ec_dev->dev, "MKBP support version %u\n",
> +			ec_dev->mkbp_event_supported - 1);
> +	}
>  
>  	/*
>  	 * Get host event wake mask, assume all events are wake events
> @@ -530,28 +534,19 @@ static int get_next_event(struct cros_ec_device *ec_dev)
>  {
>  	u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)];
>  	struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
> -	static int cmd_version = 1;
> -	int ret;
> +	const int cmd_version = ec_dev->mkbp_event_supported - 1;
>  
>  	if (ec_dev->suspended) {
>  		dev_dbg(ec_dev->dev, "Device suspended.\n");
>  		return -EHOSTDOWN;
>  	}
>  
> -	if (cmd_version == 1) {
> -		ret = get_next_event_xfer(ec_dev, msg, cmd_version,
> -				sizeof(struct ec_response_get_next_event_v1));
> -		if (ret < 0 || msg->result != EC_RES_INVALID_VERSION)
> -			return ret;
> -
> -		/* Fallback to version 0 for future send attempts */
> -		cmd_version = 0;
> -	}
> -
> -	ret = get_next_event_xfer(ec_dev, msg, cmd_version,
> +	if (cmd_version == 0)
> +		return get_next_event_xfer(ec_dev, msg, 0,
>  				  sizeof(struct ec_response_get_next_event));
>  
> -	return ret;
> +	return get_next_event_xfer(ec_dev, msg, cmd_version,
> +				sizeof(struct ec_response_get_next_event_v1));
>  }
>  
>  static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
> @@ -607,11 +602,13 @@ EXPORT_SYMBOL(cros_ec_get_next_event);
>  
>  u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
>  {
> +	u32 event_type =
> +		ec_dev->event_data.event_type & EC_MKBP_EVENT_TYPE_MASK;
>  	u32 host_event;
>  
>  	BUG_ON(!ec_dev->mkbp_event_supported);
>  
> -	if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
> +	if (event_type != EC_MKBP_EVENT_HOST_EVENT)
>  		return 0;
>  
>  	if (ec_dev->event_size != sizeof(host_event)) {
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index e44e3ec8a9c7d..cb07ee95a6eb8 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -119,7 +119,9 @@ struct cros_ec_command {
>   *            code.
>   * @pkt_xfer: Send packet to EC and get response.
>   * @lock: One transaction at a time.
> - * @mkbp_event_supported: True if this EC supports the MKBP event protocol.
> + * @mkbp_event_supported: 0 if MKBP not supported. Otherwise its value is
> + *                        the maximum supported version of the MKBP host event
> + *                        command + 1.
>   * @event_notifier: Interrupt event notifier for transport devices.
>   * @event_data: Raw payload transferred with the MKBP event.
>   * @event_size: Size in bytes of the event data.
> @@ -152,7 +154,8 @@ struct cros_ec_device {
>  	int (*pkt_xfer)(struct cros_ec_device *ec,
>  			struct cros_ec_command *msg);
>  	struct mutex lock;
> -	bool mkbp_event_supported;
> +	/* 0 == not supported, otherwise it supports version x - 1 */
> +	u8 mkbp_event_supported;
>  	struct blocking_notifier_head event_notifier;
>  
>  	struct ec_response_get_next_event_v1 event_data;
> diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
> index 9a9631f0559e2..3f013593d0107 100644
> --- a/include/linux/mfd/cros_ec_commands.h
> +++ b/include/linux/mfd/cros_ec_commands.h
> @@ -2146,6 +2146,14 @@ struct ec_result_keyscan_seq_ctrl {
>   */
>  #define EC_CMD_GET_NEXT_EVENT 0x67
>  
> +#define EC_MKBP_HAS_MORE_EVENTS_SHIFT 7
> +
> +/* EC can provide more MKBP events to host */
> +#define EC_MKBP_HAS_MORE_EVENTS (1 << EC_MKBP_HAS_MORE_EVENTS_SHIFT)
> +
> +/* The mask to apply to get the raw event type */
> +#define EC_MKBP_EVENT_TYPE_MASK ((1 << EC_MKBP_HAS_MORE_EVENTS_SHIFT) - 1)
> +
>  enum ec_mkbp_event {
>  	/* Keyboard matrix changed. The event data is the new matrix state. */
>  	EC_MKBP_EVENT_KEY_MATRIX = 0,
> @@ -2173,6 +2181,13 @@ enum ec_mkbp_event {
>  
>  	/* Number of MKBP events */
>  	EC_MKBP_EVENT_COUNT,
> +
> +	/*
> +	 * Maximum possible event type
> +	 * The most significant bit of event type is used to indicate that
> +	 * the EC has multiple events for the AP to serve
> +	 */
> +	EC_MKBP_EVENT_MAX_TYPE = EC_MKBP_EVENT_TYPE_MASK,
>  };
>  
>  union ec_response_get_next_data {

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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