drivers/media/video/saa7164/saa7164-buffer.c

   1 /*
   2  *  Driver for the NXP SAA7164 PCIe bridge
   3  *
   4  *  Copyright (c) 2009 Steven Toth <stoth@kernellabs.com>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include <linux/slab.h>
  23
  24 #include "saa7164.h"
  25
  26 /* The PCI address space for buffer handling looks like this:
  27
  28  +-u32 wide-------------+
  29  |                      +
  30  +-u64 wide------------------------------------+
  31  +                                             +
  32  +----------------------+
  33  | CurrentBufferPtr     + Pointer to current PCI buffer >-+
  34  +----------------------+                                 |
  35  | Unused               +                                 |
  36  +----------------------+                                 |
  37  | Pitch                + = 188 (bytes)                   |
  38  +----------------------+                                 |
  39  | PCI buffer size      + = pitch * number of lines (312) |
  40  +----------------------+                                 |
  41  |0| Buf0 Write Offset  +                                 |
  42  +----------------------+                                 v
  43  |1| Buf1 Write Offset  +                                 |
  44  +----------------------+                                 |
  45  |2| Buf2 Write Offset  +                                 |
  46  +----------------------+                                 |
  47  |3| Buf3 Write Offset  +                                 |
  48  +----------------------+                                 |
  49  ... More write offsets                                   |
  50  +---------------------------------------------+          |
  51  +0| set of ptrs to PCI pagetables             +          |
  52  +---------------------------------------------+          |
  53  +1| set of ptrs to PCI pagetables             + <--------+
  54  +---------------------------------------------+
  55  +2| set of ptrs to PCI pagetables             +
  56  +---------------------------------------------+
  57  +3| set of ptrs to PCI pagetables             + >--+
  58  +---------------------------------------------+    |
  59  ... More buffer pointers                           |  +----------------+
  60                                                     +->| pt[0] TS data  |
  61                                                     |  +----------------+
  62                                                     |
  63                                                     |  +----------------+
  64                                                     +->| pt[1] TS data  |
  65                                                     |  +----------------+
  66                                                     | etc
  67  */
  68
  69 /* Allocate a new buffer structure and associated PCI space in bytes.
  70  * len must be a multiple of sizeof(u64)
  71  */
  72 struct saa7164_buffer *saa7164_buffer_alloc(struct saa7164_tsport *port,
  73         u32 len)
  74 {
  75         struct saa7164_buffer *buf = 0;
  76         struct saa7164_dev *dev = port->dev;
  77         int i;
  78
  79         if ((len == 0) || (len >= 65536) || (len % sizeof(u64))) {
  80                 log_warn("%s() SAA_ERR_BAD_PARAMETER\n", __func__);
  81                 goto ret;
  82         }
  83
  84         buf = kzalloc(sizeof(struct saa7164_buffer), GFP_KERNEL);
  85         if (buf == NULL) {
  86                 log_warn("%s() SAA_ERR_NO_RESOURCES\n", __func__);
  87                 goto ret;
  88         }
  89
  90         buf->port = port;
  91         buf->flags = SAA7164_BUFFER_FREE;
  92         /* TODO: arg len is being ignored */
  93         buf->pci_size = SAA7164_PT_ENTRIES * 0x1000;
  94         buf->pt_size = (SAA7164_PT_ENTRIES * sizeof(u64)) + 0x1000;
  95
  96         /* Allocate contiguous memory */
  97         buf->cpu = pci_alloc_consistent(port->dev->pci, buf->pci_size,
  98                 &buf->dma);
  99         if (!buf->cpu)
 100                 goto fail1;
 101
 102         buf->pt_cpu = pci_alloc_consistent(port->dev->pci, buf->pt_size,
 103                 &buf->pt_dma);
 104         if (!buf->pt_cpu)
 105                 goto fail2;
 106
 107         /* init the buffers to a known pattern, easier during debugging */
 108         memset(buf->cpu, 0xff, buf->pci_size);
 109         memset(buf->pt_cpu, 0xff, buf->pt_size);
 110
 111         dprintk(DBGLVL_BUF, "%s()   allocated buffer @ 0x%p\n", __func__, buf);
 112         dprintk(DBGLVL_BUF, "  pci_cpu @ 0x%p    dma @ 0x%08lx len = 0x%x\n",
 113                 buf->cpu, (long)buf->dma, buf->pci_size);
 114         dprintk(DBGLVL_BUF, "   pt_cpu @ 0x%p pt_dma @ 0x%08lx len = 0x%x\n",
 115                 buf->pt_cpu, (long)buf->pt_dma, buf->pt_size);
 116
 117         /* Format the Page Table Entries to point into the data buffer */
 118         for (i = 0 ; i < SAA7164_PT_ENTRIES; i++) {
 119
 120                 *(buf->pt_cpu + i) = buf->dma + (i * 0x1000); /* TODO */
 121
 122         }
 123
 124         goto ret;
 125
 126 fail2:
 127         pci_free_consistent(port->dev->pci, buf->pci_size, buf->cpu, buf->dma);
 128 fail1:
 129         kfree(buf);
 130
 131         buf = 0;
 132 ret:
 133         return buf;
 134 }
 135
 136 int saa7164_buffer_dealloc(struct saa7164_tsport *port,
 137         struct saa7164_buffer *buf)
 138 {
 139         struct saa7164_dev *dev;
 140
 141         if (!buf || !port)
 142                 return SAA_ERR_BAD_PARAMETER;
 143         dev = port->dev;
 144
 145         dprintk(DBGLVL_BUF, "%s() deallocating buffer @ 0x%p\n", __func__, buf);
 146
 147         if (buf->flags != SAA7164_BUFFER_FREE)
 148                 log_warn(" freeing a non-free buffer\n");
 149
 150         pci_free_consistent(port->dev->pci, buf->pci_size, buf->cpu, buf->dma);
 151         pci_free_consistent(port->dev->pci, buf->pt_size, buf->pt_cpu,
 152                 buf->pt_dma);
 153
 154         kfree(buf);
 155
 156         return SAA_OK;
 157 }
 158