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SubjectRe: [PATCH v2 3/5] mfd: cros-ec: Introduce CEC commands and events definitions.
Hi Neil,

2018-05-18 15:05 GMT+02:00 Neil Armstrong <narmstrong@baylibre.com>:
> The EC can expose a CEC bus, this patch adds the CEC related definitions
> needed by the cros-ec-cec driver.
> 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@chromium.org>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
> drivers/platform/chrome/cros_ec_proto.c | 40 +++++++++++++----
> include/linux/mfd/cros_ec.h | 2 +-
> include/linux/mfd/cros_ec_commands.h | 80 +++++++++++++++++++++++++++++++++
> 3 files changed, 112 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;

Personal opinion, but I don't like this static here, and also I don't
think this is scalable. Could we ask for the command version?

> 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;
> }
>

So we always do a failed transfer on all these EC devices that does
not support CEC. I am wondering if wouldn't be better pass the command
version to the cros_ec_get_next_event function. The driver should know
which version to use, just a random idea.

> + 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..16c3a2b 100644
> --- a/include/linux/mfd/cros_ec_commands.h
> +++ b/include/linux/mfd/cros_ec_commands.h

This file is going to be very big and as requested by Lee I plan to
convert this file to the kernel-doc format, this patch introduces some
new structs so could you document the new structs in the suggested
format?

> @@ -804,6 +804,8 @@ enum ec_feature_code {
> EC_FEATURE_MOTION_SENSE_FIFO = 24,
> /* EC has RTC feature that can be controlled by host commands */
> EC_FEATURE_RTC = 27,
> + /* EC supports CEC commands */
> + EC_FEATURE_CEC = 35,
> };
>
> #define EC_FEATURE_MASK_0(event_code) (1UL << (event_code % 32))
> @@ -2078,6 +2080,12 @@ enum ec_mkbp_event {
> /* EC sent a sysrq command */
> EC_MKBP_EVENT_SYSRQ = 6,
>
> + /* Notify the AP that something happened on CEC */
> + EC_MKBP_CEC_EVENT = 8,
> +
> + /* Send an incoming CEC message to the AP */
> + EC_MKBP_EVENT_CEC_MESSAGE = 9,
> +
> /* Number of MKBP events */
> EC_MKBP_EVENT_COUNT,
> };
> @@ -2093,12 +2101,31 @@ union ec_response_get_next_data {
> uint32_t sysrq;
> } __packed;
>
> +union ec_response_get_next_data_v1 {
> + uint8_t key_matrix[16];
> +
> + /* Unaligned */
> + uint32_t host_event;
> +
> + uint32_t buttons;
> + uint32_t switches;
> + uint32_t sysrq;
> + uint32_t cec_events;
> + uint8_t cec_message[16];
> +} __packed;
> +
> 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
> @@ -2828,6 +2855,59 @@ struct ec_params_reboot_ec {
> /* Current version of ACPI memory address space */
> #define EC_ACPI_MEM_VERSION_CURRENT 1
>
> +/*****************************************************************************/
> +/*
> + * HDMI CEC commands
> + *
> + * These commands are for sending and receiving message via HDMI CEC
> + */
> +#define MAX_CEC_MSG_LEN 16
> +
> +/* CEC message from the AP to be written on the CEC bus */
> +#define EC_CMD_CEC_WRITE_MSG 0x00B8
> +
> +/* Message to write to the CEC bus */
> +struct ec_params_cec_write {
> + uint8_t msg[MAX_CEC_MSG_LEN];
> +} __packed;
> +
> +/* Set various CEC parameters */
> +#define EC_CMD_CEC_SET 0x00BA
> +
> +struct ec_params_cec_set {
> + uint8_t cmd; /* enum cec_command */
> + union {
> + uint8_t enable;
> + uint8_t address;
> + };
> +} __packed;
> +
> +/* Read various CEC parameters */
> +#define EC_CMD_CEC_GET 0x00BB
> +
> +struct ec_params_cec_get {
> + uint8_t cmd; /* enum cec_command */
> +} __packed;
> +
> +struct ec_response_cec_get {
> + union {
> + uint8_t enable;
> + uint8_t address;
> + };
> +} __packed;
> +
> +enum cec_command {
> + /* CEC reading, writing and events enable */
> + CEC_CMD_ENABLE,
> + /* CEC logical address */
> + CEC_CMD_LOGICAL_ADDRESS,
> +};
> +
> +/* Events from CEC to AP */
> +enum mkbp_cec_event {
> + EC_MKBP_CEC_SEND_OK = 1 << 0,
> + EC_MKBP_CEC_SEND_FAILED = 1 << 1,

Use the BIT() macro.

> +};
>
> /*****************************************************************************/
> /*
> --
> 2.7.4
>

Thanks,
Enric

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