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platform/chrome: Add new driver for Wilco EC

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This EC is an incompatible variant of the typical Chrome OS embedded
controller.  It uses the same low-level communication and a similar
protocol with some significant differences.  The EC firmware does
not support the same mailbox commands so it is not registered as a
cros_ec device type.  This commit exports the wilco_ec_mailbox()
function so that other modules can use it to communicate with the EC.

Signed-off-by: Duncan Laurie <dlaurie@google.com>
Signed-off-by: Nick Crews <ncrews@chromium.org>
[Fix the sparse warning: symbol 'wilco_ec_transfer' was not declared]
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
[Fix Kconfig dependencies for wilco_ec]
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
This commit is contained in:
Nick Crews
2019-02-08 17:37:17 -07:00
committed by Enric Balletbo i Serra
parent 6b7cb2227d
commit 7b3d4f44ab
7 changed files with 499 additions and 0 deletions
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140
include/linux/platform_data/wilco-ec.h Normal file
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/* SPDX-License-Identifier: GPL-2.0 */
/*
* ChromeOS Wilco Embedded Controller
*
* Copyright 2018 Google LLC
*/
#ifndef WILCO_EC_H
#define WILCO_EC_H
#include <linux/device.h>
#include <linux/kernel.h>
/* Message flags for using the mailbox() interface */
#define WILCO_EC_FLAG_NO_RESPONSE BIT(0) /* EC does not respond */
#define WILCO_EC_FLAG_EXTENDED_DATA BIT(1) /* EC returns 256 data bytes */
#define WILCO_EC_FLAG_RAW_REQUEST BIT(2) /* Do not trim request data */
#define WILCO_EC_FLAG_RAW_RESPONSE BIT(3) /* Do not trim response data */
#define WILCO_EC_FLAG_RAW (WILCO_EC_FLAG_RAW_REQUEST | \
WILCO_EC_FLAG_RAW_RESPONSE)
/* Normal commands have a maximum 32 bytes of data */
#define EC_MAILBOX_DATA_SIZE 32
/* Extended commands have 256 bytes of response data */
#define EC_MAILBOX_DATA_SIZE_EXTENDED 256
/**
* struct wilco_ec_device - Wilco Embedded Controller handle.
* @dev: Device handle.
* @mailbox_lock: Mutex to ensure one mailbox command at a time.
* @io_command: I/O port for mailbox command. Provided by ACPI.
* @io_data: I/O port for mailbox data. Provided by ACPI.
* @io_packet: I/O port for mailbox packet data. Provided by ACPI.
* @data_buffer: Buffer used for EC communication. The same buffer
* is used to hold the request and the response.
* @data_size: Size of the data buffer used for EC communication.
*/
struct wilco_ec_device {
struct device *dev;
struct mutex mailbox_lock;
struct resource *io_command;
struct resource *io_data;
struct resource *io_packet;
void *data_buffer;
size_t data_size;
};
/**
* struct wilco_ec_request - Mailbox request message format.
* @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
* @checksum: Sum of all bytes must be 0.
* @mailbox_id: Mailbox identifier, specifies the command set.
* @mailbox_version: Mailbox interface version %EC_MAILBOX_VERSION
* @reserved: Set to zero.
* @data_size: Length of request, data + last 2 bytes of the header.
* @command: Mailbox command code, unique for each mailbox_id set.
* @reserved_raw: Set to zero for most commands, but is used by
* some command types and for raw commands.
*/
struct wilco_ec_request {
u8 struct_version;
u8 checksum;
u16 mailbox_id;
u8 mailbox_version;
u8 reserved;
u16 data_size;
u8 command;
u8 reserved_raw;
} __packed;
/**
* struct wilco_ec_response - Mailbox response message format.
* @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
* @checksum: Sum of all bytes must be 0.
* @result: Result code from the EC. Non-zero indicates an error.
* @data_size: Length of the response data buffer.
* @reserved: Set to zero.
* @mbox0: EC returned data at offset 0 is unused (always 0) so this byte
* is treated as part of the header instead of the data.
* @data: Response data buffer. Max size is %EC_MAILBOX_DATA_SIZE_EXTENDED.
*/
struct wilco_ec_response {
u8 struct_version;
u8 checksum;
u16 result;
u16 data_size;
u8 reserved[2];
u8 mbox0;
u8 data[0];
} __packed;
/**
* enum wilco_ec_msg_type - Message type to select a set of command codes.
* @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior.
* @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property.
* @WILCO_EC_MSG_TELEMETRY_SHORT: 32 bytes of telemetry data provided by the EC.
* @WILCO_EC_MSG_TELEMETRY_LONG: 256 bytes of telemetry data provided by the EC.
*/
enum wilco_ec_msg_type {
WILCO_EC_MSG_LEGACY = 0x00f0,
WILCO_EC_MSG_PROPERTY = 0x00f2,
WILCO_EC_MSG_TELEMETRY_SHORT = 0x00f5,
WILCO_EC_MSG_TELEMETRY_LONG = 0x00f6,
};
/**
* struct wilco_ec_message - Request and response message.
* @type: Mailbox message type.
* @flags: Message flags, e.g. %WILCO_EC_FLAG_NO_RESPONSE.
* @command: Mailbox command code.
* @result: Result code from the EC. Non-zero indicates an error.
* @request_size: Number of bytes to send to the EC.
* @request_data: Buffer containing the request data.
* @response_size: Number of bytes expected from the EC.
* This is 32 by default and 256 if the flag
* is set for %WILCO_EC_FLAG_EXTENDED_DATA
* @response_data: Buffer containing the response data, should be
* response_size bytes and allocated by caller.
*/
struct wilco_ec_message {
enum wilco_ec_msg_type type;
u8 flags;
u8 command;
u8 result;
size_t request_size;
void *request_data;
size_t response_size;
void *response_data;
};
/**
* wilco_ec_mailbox() - Send request to the EC and receive the response.
* @ec: Wilco EC device.
* @msg: Wilco EC message.
*
* Return: Number of bytes received or negative error code on failure.
*/
int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
#endif /* WILCO_EC_H */