linux/drivers/media/pci/saa7164/saa7164-buffer.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Driver for the NXP SAA7164 PCIe bridge
 *
 *  Copyright (c) 2010-2015 Steven Toth <[email protected]>
 */

#include <linux/slab.h>

#include "saa7164.h"

/* The PCI address space for buffer handling looks like this:
 *
 * +-u32 wide-------------+
 * |                      +
 * +-u64 wide------------------------------------+
 * +                                             +
 * +----------------------+
 * | CurrentBufferPtr     + Pointer to current PCI buffer >-+
 * +----------------------+                                 |
 * | Unused               +                                 |
 * +----------------------+                                 |
 * | Pitch                + = 188 (bytes)                   |
 * +----------------------+                                 |
 * | PCI buffer size      + = pitch * number of lines (312) |
 * +----------------------+                                 |
 * |0| Buf0 Write Offset  +                                 |
 * +----------------------+                                 v
 * |1| Buf1 Write Offset  +                                 |
 * +----------------------+                                 |
 * |2| Buf2 Write Offset  +                                 |
 * +----------------------+                                 |
 * |3| Buf3 Write Offset  +                                 |
 * +----------------------+                                 |
 * ... More write offsets                                   |
 * +---------------------------------------------+          |
 * +0| set of ptrs to PCI pagetables             +          |
 * +---------------------------------------------+          |
 * +1| set of ptrs to PCI pagetables             + <--------+
 * +---------------------------------------------+
 * +2| set of ptrs to PCI pagetables             +
 * +---------------------------------------------+
 * +3| set of ptrs to PCI pagetables             + >--+
 * +---------------------------------------------+    |
 * ... More buffer pointers                           |  +----------------+
 *						    +->| pt[0] TS data  |
 *						    |  +----------------+
 *						    |
 *						    |  +----------------+
 *						    +->| pt[1] TS data  |
 *						    |  +----------------+
 *						    | etc
 */

void saa7164_buffer_display(struct saa7164_buffer *buf)
{ … }
/* Allocate a new buffer structure and associated PCI space in bytes.
 * len must be a multiple of sizeof(u64)
 */
struct saa7164_buffer *saa7164_buffer_alloc(struct saa7164_port *port,
	u32 len)
{ … }

int saa7164_buffer_dealloc(struct saa7164_buffer *buf)
{ … }

int saa7164_buffer_zero_offsets(struct saa7164_port *port, int i)
{ … }

/* Write a buffer into the hardware */
int saa7164_buffer_activate(struct saa7164_buffer *buf, int i)
{ … }

int saa7164_buffer_cfg_port(struct saa7164_port *port)
{ … }

struct saa7164_user_buffer *saa7164_buffer_alloc_user(struct saa7164_dev *dev,
	u32 len)
{ … }

void saa7164_buffer_dealloc_user(struct saa7164_user_buffer *buf)
{ … }