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/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright(c) 2024 Intel Corporation. */
#ifndef __CXL_MBOX_H__
#define __CXL_MBOX_H__
#include <linux/rcuwait.h>
#include <cxl/features.h>
#include <uapi/linux/cxl_mem.h>
/**
* struct cxl_mbox_cmd - A command to be submitted to hardware.
* @opcode: (input) The command set and command submitted to hardware.
* @payload_in: (input) Pointer to the input payload.
* @payload_out: (output) Pointer to the output payload. Must be allocated by
* the caller.
* @size_in: (input) Number of bytes to load from @payload_in.
* @size_out: (input) Max number of bytes loaded into @payload_out.
* (output) Number of bytes generated by the device. For fixed size
* outputs commands this is always expected to be deterministic. For
* variable sized output commands, it tells the exact number of bytes
* written.
* @min_out: (input) internal command output payload size validation
* @poll_count: (input) Number of timeouts to attempt.
* @poll_interval_ms: (input) Time between mailbox background command polling
* interval timeouts.
* @return_code: (output) Error code returned from hardware.
*
* This is the primary mechanism used to send commands to the hardware.
* All the fields except @payload_* correspond exactly to the fields described in
* Command Register section of the CXL 2.0 8.2.8.4.5. @payload_in and
* @payload_out are written to, and read from the Command Payload Registers
* defined in CXL 2.0 8.2.8.4.8.
*/
struct cxl_mbox_cmd {
u16 opcode;
void *payload_in;
void *payload_out;
size_t size_in;
size_t size_out;
size_t min_out;
int poll_count;
int poll_interval_ms;
u16 return_code;
};
/**
* struct cxl_mailbox - context for CXL mailbox operations
* @host: device that hosts the mailbox
* @enabled_cmds: mailbox commands that are enabled by the driver
* @exclusive_cmds: mailbox commands that are exclusive to the kernel
* @payload_size: Size of space for payload
* (CXL 3.1 8.2.8.4.3 Mailbox Capabilities Register)
* @mbox_mutex: mutex protects device mailbox and firmware
* @mbox_wait: rcuwait for mailbox
* @mbox_send: @dev specific transport for transmitting mailbox commands
* @feat_cap: Features capability
*/
struct cxl_mailbox {
struct device *host;
DECLARE_BITMAP(enabled_cmds, CXL_MEM_COMMAND_ID_MAX);
DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX);
size_t payload_size;
struct mutex mbox_mutex; /* lock to protect mailbox context */
struct rcuwait mbox_wait;
int (*mbox_send)(struct cxl_mailbox *cxl_mbox, struct cxl_mbox_cmd *cmd);
enum cxl_features_capability feat_cap;
};
int cxl_mailbox_init(struct cxl_mailbox *cxl_mbox, struct device *host);
#endif
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