path: root/bmm_lib.c

/*
 *  bmm_lib.c
 *
 *  Buffer Management Module
 *
 *  User level BMM Defines/Globals/Functions
 *
 *  Li Li (lea.li@marvell.com)

 *(C) Copyright 2007 Marvell International Ltd.
 * All Rights Reserved
 */

#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "bmm_drv.h"
#include "bmm_lib.h"
#include "rb.h"

#undef DEBUG

#ifdef DEBUG
#define pr_debug(fmt, arg...) do { fprintf(stderr, fmt, ##arg); } while (0)
#else
#define pr_debug(fmt, arg...) do { if (0) fprintf(stderr, fmt, ##arg); } while (0)
#endif

static int bmm_fd = -1;
static int bmm_use;
static pthread_mutex_t bmm_mutex = PTHREAD_MUTEX_INITIALIZER;
static Rb_node bmm_virt_rb;

struct bmm_virt_buffer {
	void *vaddr;
	size_t size;
	int fd;
};

static int cmp_virt(const void *key, const void *val)
{
	const struct bmm_virt_buffer *vbuf = val;
	void *k = (void *)key;

	return (k < vbuf->vaddr) ? -1 : (k - vbuf->vaddr < vbuf->size) ? 0 : 1;
}

static struct bmm_virt_buffer *bmm_buf_find_virt(void *virt)
{
	struct bmm_virt_buffer *vbuf = NULL;
	Rb_node node;
	int found = 0;

	node = rb_find_key_n(bmm_virt_rb, virt, cmp_virt, &found);
	if (found) {
		vbuf = rb_val(node);

		pr_debug("rb: %s(%p) virt=%p size=0x%08zx\n",
			 "find_virt", virt, vbuf->vaddr,
			 vbuf->size);
	} else {
		pr_debug("rb: %s(%p): not found\n",
			"find_virt", virt);
	}

	return vbuf;
}

static void bmm_rb_virt_remove(struct bmm_virt_buffer *vbuf)
{
	Rb_node node;
	int found = 0;

	pr_debug("%s: virt=%p size=0x%08zx\n",
		 __FUNCTION__, vbuf->vaddr, vbuf->size);

	node = rb_find_key_n(bmm_virt_rb, vbuf->vaddr, cmp_virt, &found);
	assert(found);
	rb_delete_node(node);
}

static void bmm_rb_virt_insert(struct bmm_virt_buffer *vbuf)
{
	Rb_node node;
	int found = 0;

	pr_debug("%s: virt=%p size=0x%08zx\n",
		 __FUNCTION__, vbuf->vaddr, vbuf->size);

	node = rb_find_key_n(bmm_virt_rb, vbuf->vaddr, cmp_virt, &found);
	if (found) {
		struct bmm_virt_buffer *f = rb_val(node);
		pr_debug("rb: found: %p\n", f);
		pr_debug("  v%p s0x%08zx\n", f->vaddr, f->size);
	}
	assert(found == 0);
	rb_insert_b(node, vbuf);
}

/**
 * bmm_dmabuf_alloc - allocate a DMA buffer
 * @size: size of DMA buffer
 * @attr: attributes of DMA buffer
 * @align: requested alignment
 *
 * Returns: dma_buf file descriptor referring to buffer
 */
int bmm_dmabuf_alloc(unsigned long size, int attr, unsigned align)
{
	struct bmm_dmabuf_alloc arg;
	int ret;

	/* obsolete, only for back-compatible */
	if (attr & BMM_ATTR_NONBUFFERABLE && attr & BMM_ATTR_NONCACHEABLE)
		attr = BMM_ATTR_NONCACHED;

	if (!(attr & BMM_ATTR_NONBUFFERABLE) && attr & BMM_ATTR_NONCACHEABLE)
		attr = BMM_ATTR_WRITECOMBINE;

	arg.size = size;
	arg.align = align;
	arg.attr = attr;

	ret = ioctl(bmm_fd, BMM_DMABUF_ALLOC, &arg);

	return ret < 0 ? ret : arg.fd;
}

/**
 * bmm_dmabuf_map - map an allcoated DMA buffer
 * @fd: dma_buf file descriptor
 * @offset: page aligned offset into DMA buffer
 * @size: size of buffer to map
 *
 * Map the requested buffer into userspace with the requested offset and size.
 *
 * Returns: address of mapped buffer, or NULL on error
 */
void *bmm_dmabuf_map(int fd, unsigned offset, unsigned size)
{
	struct bmm_virt_buffer *vbuf;
	void *vaddr;

	vaddr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset);
	if (vaddr == (void *)-1)
		return NULL;

	vbuf = malloc(sizeof(*vbuf));
	if (!vbuf) {
		munmap(vaddr, size);
		return NULL;
	}

	vbuf->vaddr = vaddr;
	vbuf->size = size;
	vbuf->fd = fd;

	pthread_mutex_lock(&bmm_mutex);
	bmm_rb_virt_insert(vbuf);
	pthread_mutex_unlock(&bmm_mutex);

	return vaddr;
}

/*
 * bmm_dmabuf_unmap - unmap a dma_buf mapped previously with bmm_dmabuf_map
 * @vaddr: virtual address returned from bmm_dmabuf_map()
 */
void bmm_dmabuf_unmap(void *vaddr)
{
	struct bmm_virt_buffer *vbuf;

	pthread_mutex_lock(&bmm_mutex);
	vbuf = bmm_buf_find_virt(vaddr);
	if (vbuf)
		bmm_rb_virt_remove(vbuf);
	pthread_mutex_unlock(&bmm_mutex);

	if (vbuf) {
		munmap(vbuf->vaddr, vbuf->size);
		free(vbuf);
	}
}

int bmm_dmabuf_flush(int fd, void *addr, unsigned offset, unsigned size, unsigned direction)
{
	struct bmm_virt_buffer *vbuf;
	int ret = 0;

	pthread_mutex_lock(&bmm_mutex);
	vbuf = bmm_buf_find_virt(addr);
	pthread_mutex_unlock(&bmm_mutex);

	if (vbuf) {
		struct bmm_dmabuf_flush arg;

		if (fd != vbuf->fd) {
			errno = EINVAL;
			return -1;
		}

		arg.size = size;
		arg.offset = offset;
		arg.ptr = (uint64_t)(uintptr_t)addr;
		arg.fd = vbuf->fd;
		arg.direction = direction;

		ret = ioctl(bmm_fd, BMM_DMABUF_FLUSH, &arg);
	}
	return ret;
}

/**
 * bmm_dmabuf_fd - return the dma_buf file descriptor for a mapped dma_buf
 * @vaddr: virtual address returned from bmm_dmabuf_map()
 *
 * Returns the dma_buf file descriptor for the dma_buf previously mapped
 * with bmm_dmabuf_map(), or -1 on error.
 */
int bmm_dmabuf_fd(void *vaddr)
{
	struct bmm_virt_buffer *vbuf;
	int fd = -1;

	pthread_mutex_lock(&bmm_mutex);
	vbuf = bmm_buf_find_virt(vaddr);
	if (vbuf)
		fd = vbuf->fd;
	pthread_mutex_unlock(&bmm_mutex);

	return fd;
}

/**
 * bmm_dmabuf_free - free the dma_buf file descriptor
 * @fd: dma_buf file descriptor returned by bmm_dmabuf_alloc()
 *
 * Closes the file descriptor associated with the DMA buffer.  The actual
 * DMA buffer will only be freed when all references to it are gone - in
 * other words, after the buffer has been completely unmapped and any
 * imported references are also released.
 *
 * After this call has completed, the file descriptor returned by a call
 * to bmm_dmabuf_fd() is invalid.
 */
void bmm_dmabuf_free(int fd)
{
	close(fd);
}

int bmm_init(void)
{
	pthread_mutex_lock(&bmm_mutex);
	if (bmm_use++ == 0) {
		bmm_virt_rb = make_rb();
		if (!bmm_virt_rb)
			goto err_rb;

		/* attempt to open the BMM driver */
		bmm_fd = open(BMM_DEVICE_FILE, O_RDWR | O_CLOEXEC);
		pr_debug("BMM device fd: %d\n", bmm_fd);
		if (bmm_fd < 0)
			goto err_open;
	}
	pthread_mutex_unlock(&bmm_mutex);

	return bmm_fd;

 err_open:
	rb_free_tree(bmm_virt_rb);
	bmm_virt_rb = NULL;
 err_rb:
	bmm_use--;
	pthread_mutex_unlock(&bmm_mutex);
	return bmm_fd;
}

void bmm_exit(void)
{
	pthread_mutex_lock(&bmm_mutex);
	if (bmm_use && --bmm_use == 0) {
		Rb_node node;

		/* Clean up dangling buffers which the app hasn't released. */
		rb_traverse(node, bmm_virt_rb) {
			struct bmm_virt_buffer *vbuf = rb_val(node);

			munmap(vbuf->vaddr, vbuf->size);
			close(vbuf->fd);
			free(vbuf);
		}

		rb_free_tree(bmm_virt_rb);
		bmm_virt_rb = NULL;

		close(bmm_fd);
		bmm_fd = -1;
	}
	pthread_mutex_unlock(&bmm_mutex);
}

/*
 * Destructor for this library: ensure it gets cleaned up when the
 * library is unloaded.
 */
static void __attribute__((destructor)) bmm_destruct(void)
{
	if (bmm_use) {
		bmm_use = 1;
		bmm_exit();
	}
}