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

From: Lee Jones
Date: Mon Jun 18 2018 - 03:44:54 EST


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@xxxxxxxxxxxx>
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> Tested-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> ---
> 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?

> 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

--
Lee Jones [æçæ]
Linaro Services Technical Lead
Linaro.org â Open source software for ARM SoCs
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