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/*
* Android/Easel coprocessor communication.
*
* Copyright 2016 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _UAPI__GOOGLE_EASEL_COMM_H
#define _UAPI__GOOGLE_EASEL_COMM_H
#include <linux/compiler.h>
#include <linux/types.h>
/* Maximum message data size 12KB */
#define EASELCOMM_MAX_MESSAGE_SIZE (12 * 1024)
/* Maximum service count */
#define EASELCOMM_SERVICE_COUNT 64
/* Easel message identifier. Compatible with libeasel defines. */
typedef __u64 easelcomm_msgid_t;
struct easelcomm_wait {
__s32 timeout_ms; /* timeout in ms; -1 means indefinite */
};
/*
* Userspace/kernel interface message descriptor. libeasel converts
* between its representation of messages and these descriptors, plus the
* buffer descriptors below, when passing messages between the kernel and
* userspace.
*/
struct easelcomm_kmsg_desc {
/* 64-bit IDs go first for 32/64-bit struct packing conformity */
easelcomm_msgid_t message_id; /* message ID */
easelcomm_msgid_t in_reply_to; /* msg ID replied to if non-zero */
__u32 message_size; /* size in bytes of the message data */
__u32 dma_buf_size; /* size of the DMA buffer transfer */
__u32 need_reply; /* non-zero if reply requested */
__u32 replycode; /* replycode if in_reply_to != 0 */
struct easelcomm_wait wait;
};
enum easelcomm_dma_buffer_type {
EASELCOMM_DMA_BUFFER_UNUSED = 0,
EASELCOMM_DMA_BUFFER_USER,
EASELCOMM_DMA_BUFFER_DMA_BUF
};
/*
* Local buffer descriptor argument for ioctls that read and write message
* or DMA buffers. The message_id describes an in-progress local outgoing
* message for which the message data is being written or the DMA source
* buffer is being set, or a remote incoming message for which the message
* data is being read or the DMA destination buffer is being set.
*/
struct easelcomm_kbuf_desc {
easelcomm_msgid_t message_id; /* ID of message for this transfer */
void __user *buf; /* local buffer source or dest */
int dma_buf_fd; /* fd of local dma_buf */
int buf_type; /* use enum easelcomm_dma_buffer_type */
__u32 buf_size; /* size of the local buffer */
struct easelcomm_wait wait;
};
/*
* Kernel driver ioctls. All ioctls return zero for success or -1 for
* error with errno set: EINVAL for invalid parameters (dmesg may contain
* further explanation), ENOMEM for out of memory, or other codes as described
* below.
*/
#define EASELCOMM_IOC_MAGIC 0xEA
/*
* Register the file descriptor for an easelcomm service. The AP client will
* flush any local client and remote server messages associated with the
* service at this time, assuming any previous traffic is stale. Registration
* by the Easel server does not flush state and will commence processing of
* any queued incoming messages previously sent to the service by a client.
* Only one fd may be registered for a service on each of the AP and Easel
* sides.
*/
#define EASELCOMM_IOC_REGISTER _IOW(EASELCOMM_IOC_MAGIC, 0, int)
/*
* Start sending an outgoing message. Reads a message descriptor and
* returns a modified descriptor with a local message ID assigned. That
* ID is then supplied in the buffer descriptors of WRITEBUF and SENDDMA
* ioctls as appropriate to supply the message data and local DMA source
* information.
*/
#define EASELCOMM_IOC_SENDMSG _IOWR(EASELCOMM_IOC_MAGIC, 1, \
struct easelcomm_kmsg_desc *)
/*
* Read the message data for an incoming message received from the
* remote. The supplied remote message ID was returned by a previous
* WAITMSG or WAITREPLY ioctl. The data is read to the specified buffer
* in the calling process. If no DMA transfer is requested by the
* associated message then successful completion of this ioctl frees the
* local kernel copy of the message.
*/
#define EASELCOMM_IOC_READDATA _IOW(EASELCOMM_IOC_MAGIC, 2, \
struct easelcomm_kbuf_desc *)
/*
* Write the message data for an outgoing message being sent to the
* remote. The supplied remote message ID was returned by a previous
* SENDMSG ioctl. The data is written from the specified buffer in the
* calling process. This ioctl sends the message to the remote upon
* successful completion; even if the message data length is zero, this
* ioctl must still follow a SENDMSG to actually send the message. If no
* DMA transfer is requested by the associated message then successful
* completion of this ioctl frees the local kernel copy of the message.
*/
#define EASELCOMM_IOC_WRITEDATA _IOW(EASELCOMM_IOC_MAGIC, 3, \
struct easelcomm_kbuf_desc *)
/*
* Initiate a DMA write for an outgoing message that includes a DMA
* transfer. The supplied local message ID was returned by a previous
* SENDMSG ioctl. The DMA data will be read from the specified buffer in the
* calling process. The ioctl returns once the DMA transfer is complete (or
* skipped due to being discarded by the remote). Successful completion of
* this ioctl frees the local kernel copy of the message.
*/
#define EASELCOMM_IOC_SENDDMA _IOW(EASELCOMM_IOC_MAGIC, 4, \
struct easelcomm_kbuf_desc *)
/*
* Specify the local destination for a DMA transfer requested by an incoming
* message. The supplied remote message ID was returned by a previous
* WAITMSG or WAITREPLY ioctl. The DMA data will be written to the specified
* buffer in the calling process; or if a NULL buffer pointer is supplied then
* the DMA transfer is discarded. The ioctl returns once the DMA transfer is
* complete (or discarded per the preceding). Successful completion of this
* ioctl frees the local kernel copy of the message.
*/
#define EASELCOMM_IOC_RECVDMA _IOW(EASELCOMM_IOC_MAGIC, 5, \
struct easelcomm_kbuf_desc *)
/*
* Wait for and return a descriptor for a reply from the remote to a
* local message that requests a reply. The message ID in the supplied
* descriptor was returned by a previous SENDMSG ioctl. This ioctl waits
* for the remote's reply message and returns a desciptor for that message.
* A READDATA ioctl should then be issued to read the message data, followed
* by a RECVDMA if a DMA transfer is requested by the reply.
*/
#define EASELCOMM_IOC_WAITREPLY _IOWR(EASELCOMM_IOC_MAGIC, 6, \
struct easelcomm_kmsg_desc *)
/*
* Wait for and return a descriptor for an incoming message from the remote
* (that is not a reply to a local message). This ioctl waits for the next
* non-reply message from the remote and returns a desciptor for that message.
* A READDATA ioctl should then be issued to read the message data, followed
* by a RECVDMA if a DMA transfer is requested by the message.
* Returns error ESHUTDOWN if a SHUTDOWN ioctl is issued for the file
* descriptor or the file descriptor has been closed.
*/
#define EASELCOMM_IOC_WAITMSG _IOWR(EASELCOMM_IOC_MAGIC, 7, \
struct easelcomm_kmsg_desc *)
/*
* Shut down the local easelcomm connection for the given file descriptor.
* Any other threads blocked on a WAITMSG using the same file descriptor will
* return an ESHUTDOWN. Any local in-progress outgoing or incoming messages
* for the registered Easel service are discarded.
*/
#define EASELCOMM_IOC_SHUTDOWN _IO(EASELCOMM_IOC_MAGIC, 8)
/*
* Any local in-progress outgoing or incoming messages for the registered Easel
* service are discarded, and the remote side is sent a command to flush its
* local messages for the service. Returns when the remote acknowledges the
* flush complete. No userspace handler is required to be registered on the
* remote to perform the flush.
*/
#define EASELCOMM_IOC_FLUSH _IO(EASELCOMM_IOC_MAGIC, 9)
/*
* The last close() of an fd also flushes any local messages for the
* registered service.
*/
#endif /* _UAPI__GOOGLE_EASEL_COMM_H */
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