linux-kernel - Re: [PATCH v7 3/6] mfd: cros-ec: Increase maximum mkbp event size

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Message-ID: <017e4688-4036-e606-7220-2e472afa0aac@baylibre.com>
Date:   Mon, 18 Jun 2018 10:35:56 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     airlied@...ux.ie, hans.verkuil@...co.com, olof@...om.net,
        seanpaul@...gle.com, sadolfsson@...gle.com, felixe@...gle.com,
        bleung@...gle.com, darekm@...gle.com, marcheu@...omium.org,
        fparent@...libre.com, dri-devel@...ts.freedesktop.org,
        linux-media@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, eballetbo@...il.com,
        Stefan Adolfsson <sadolfsson@...omium.org>
Subject: Re: [PATCH v7 3/6] mfd: cros-ec: Increase maximum mkbp event size

Hi Lee,

On 18/06/2018 09:44, Lee Jones wrote:
> On Fri, 01 Jun 2018, Neil Armstrong wrote:
> 
>> Having a 16 byte mkbp event size makes it possible to send CEC
>> messages from the EC to the AP directly inside the mkbp event
>> instead of first doing a notification and then a read.
>>
>> Signed-off-by: Stefan Adolfsson <sadolfsson@...omium.org>
>> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
>> Tested-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
>> ---
>>  drivers/platform/chrome/cros_ec_proto.c | 40 +++++++++++++++++++++++++--------
>>  include/linux/mfd/cros_ec.h             |  2 +-
>>  include/linux/mfd/cros_ec_commands.h    | 19 ++++++++++++++++
>>  3 files changed, 51 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
>> index e7bbdf9..c4f6c44 100644
>> --- a/drivers/platform/chrome/cros_ec_proto.c
>> +++ b/drivers/platform/chrome/cros_ec_proto.c
>> @@ -504,10 +504,31 @@ int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
>>  }
>>  EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
>>  
>> +static int get_next_event_xfer(struct cros_ec_device *ec_dev,
>> +			       struct cros_ec_command *msg,
>> +			       int version, uint32_t size)
>> +{
>> +	int ret;
>> +
>> +	msg->version = version;
>> +	msg->command = EC_CMD_GET_NEXT_EVENT;
>> +	msg->insize = size;
>> +	msg->outsize = 0;
>> +
>> +	ret = cros_ec_cmd_xfer(ec_dev, msg);
>> +	if (ret > 0) {
>> +		ec_dev->event_size = ret - 1;
>> +		memcpy(&ec_dev->event_data, msg->data, ec_dev->event_size);
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>>  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;
>>  
>>  	if (ec_dev->suspended) {
>> @@ -515,18 +536,19 @@ static int get_next_event(struct cros_ec_device *ec_dev)
>>  		return -EHOSTDOWN;
>>  	}
>>  
>> -	msg->version = 0;
>> -	msg->command = EC_CMD_GET_NEXT_EVENT;
>> -	msg->insize = sizeof(ec_dev->event_data);
>> -	msg->outsize = 0;
>> +	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;
>>  
>> -	ret = cros_ec_cmd_xfer(ec_dev, msg);
>> -	if (ret > 0) {
>> -		ec_dev->event_size = ret - 1;
>> -		memcpy(&ec_dev->event_data, msg->data,
>> -		       sizeof(ec_dev->event_data));
>> +		/* Fallback to version 0 for future send attempts */
>> +		cmd_version = 0;
>>  	}
>>  
>> +	ret = get_next_event_xfer(ec_dev, msg, cmd_version,
>> +				  sizeof(struct ec_response_get_next_event));
>> +
>>  	return ret;
>>  }
>>  
>> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
>> index f36125e..32caef3 100644
>> --- a/include/linux/mfd/cros_ec.h
>> +++ b/include/linux/mfd/cros_ec.h
>> @@ -147,7 +147,7 @@ struct cros_ec_device {
>>  	bool mkbp_event_supported;
>>  	struct blocking_notifier_head event_notifier;
>>  
>> -	struct ec_response_get_next_event event_data;
>> +	struct ec_response_get_next_event_v1 event_data;
>>  	int event_size;
>>  	u32 host_event_wake_mask;
>>  };
>> diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
>> index f2edd99..cc0768e 100644
>> --- a/include/linux/mfd/cros_ec_commands.h
>> +++ b/include/linux/mfd/cros_ec_commands.h
>> @@ -2093,12 +2093,31 @@ union ec_response_get_next_data {
>>  	uint32_t   sysrq;
>>  } __packed;
>>  
>> +union ec_response_get_next_data_v1 {
>> +	uint8_t   key_matrix[16];
>> +
>> +	/* Unaligned */
> 
> That's funny!
> 
>> +	uint32_t  host_event;
>> +
>> +	uint32_t   buttons;
>> +	uint32_t   switches;
>> +	uint32_t   sysrq;
>> +	uint32_t   cec_events;
>> +	uint8_t    cec_message[16];
> 
> Since there are some whitespace alignment issues in here.
> 
>> +} __packed;
> 
> How come these guys have kerneldoc headers?

Can you explicit what should be changed here ?

Thanks,
Neil

> 
>>  struct ec_response_get_next_event {
>>  	uint8_t event_type;
>>  	/* Followed by event data if any */
>>  	union ec_response_get_next_data data;
>>  } __packed;
>>  
>> +struct ec_response_get_next_event_v1 {
>> +	uint8_t event_type;
>> +	/* Followed by event data if any */
>> +	union ec_response_get_next_data_v1 data;
>> +} __packed;
>> +
>>  /* Bit indices for buttons and switches.*/
>>  /* Buttons */
>>  #define EC_MKBP_POWER_BUTTON	0
>