linux/drivers/hid/intel-ish-hid/ishtp/dma-if.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * ISHTP DMA I/F functions
 *
 * Copyright (c) 2003-2016, Intel Corporation.
 */

#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include "ishtp-dev.h"
#include "client.h"

/**
 * ishtp_cl_alloc_dma_buf() - Allocate DMA RX and TX buffer
 * @dev: ishtp device
 *
 * Allocate RX and TX DMA buffer once during bus setup.
 * It allocates 1MB, RX and TX DMA buffer, which are divided
 * into slots.
 */
void	ishtp_cl_alloc_dma_buf(struct ishtp_device *dev)
{ … }

/**
 * ishtp_cl_free_dma_buf() - Free DMA RX and TX buffer
 * @dev: ishtp device
 *
 * Free DMA buffer when all clients are released. This is
 * only happens during error path in ISH built in driver
 * model
 */
void	ishtp_cl_free_dma_buf(struct ishtp_device *dev)
{ … }

/*
 * ishtp_cl_get_dma_send_buf() - Get a DMA memory slot
 * @dev:	ishtp device
 * @size:	Size of memory to get
 *
 * Find and return free address of "size" bytes in dma tx buffer.
 * the function will mark this address as "in-used" memory.
 *
 * Return: NULL when no free buffer else a buffer to copy
 */
void *ishtp_cl_get_dma_send_buf(struct ishtp_device *dev,
				uint32_t size)
{ … }

/*
 * ishtp_cl_release_dma_acked_mem() - Release DMA memory slot
 * @dev:	ishtp device
 * @msg_addr:	message address of slot
 * @size:	Size of memory to get
 *
 * Release_dma_acked_mem - returnes the acked memory to free list.
 * (from msg_addr, size bytes long)
 */
void ishtp_cl_release_dma_acked_mem(struct ishtp_device *dev,
				    void *msg_addr,
				    uint8_t size)
{ … }