platform/chrome: Add new driver for Wilco EC
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>
diff --git a/include/linux/platform_data/wilco-ec.h b/include/linux/platform_data/wilco-ec.h
new file mode 100644
index 0000000..0feb4b5
--- /dev/null
+++ b/include/linux/platform_data/wilco-ec.h
@@ -0,0 +1,140 @@
+/* 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 */