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 "saa7164.h"
  23
  24 /* The PCI address space for buffer handling looks like this:
  25
  26  +-u32 wide-------------+
  27  |                      +
  28  +-u64 wide------------------------------------+
  29  +                                             +
  30  +----------------------+
  31  | CurrentBufferPtr     + Pointer to current PCI buffer >-+
  32  +----------------------+                                 |
  33  | Unused               +                                 |
  34  +----------------------+                                 |
  35  | Pitch                + = 188 (bytes)                   |
  36  +----------------------+                                 |
  37  | PCI buffer size      + = pitch * number of lines (312) |
  38  +----------------------+                                 |
  39  |0| Buf0 Write Offset  +                                 |
  40  +----------------------+                                 v
  41  |1| Buf1 Write Offset  +                                 |
  42  +----------------------+                                 |
  43  |2| Buf2 Write Offset  +                                 |
  44  +----------------------+                                 |
  45  |3| Buf3 Write Offset  +                                 |
  46  +----------------------+                                 |
  47  ... More write offsets                                   |
  48  +---------------------------------------------+          |
  49  +0| set of ptrs to PCI pagetables             +          |
  50  +---------------------------------------------+          |
  51  +1| set of ptrs to PCI pagetables             + <--------+
  52  +---------------------------------------------+
  53  +2| set of ptrs to PCI pagetables             +
  54  +---------------------------------------------+
  55  +3| set of ptrs to PCI pagetables             + >--+
  56  +---------------------------------------------+    |
  57  ... More buffer pointers                           |  +----------------+
  58                                                     +->| pt[0] TS data  |
  59                                                     |  +----------------+
  60                                                     |
  61                                                     |  +----------------+
  62                                                     +->| pt[1] TS data  |
  63                                                     |  +----------------+
  64                                                     | etc
  65  */
  66
  67 /* Allocate a new buffer structure and associated PCI space in bytes.
  68  * len must be a multiple of sizeof(u64)
  69  */
  70 struct saa7164_buffer *saa7164_buffer_alloc(struct saa7164_tsport *port,
  71         u32 len)
  72 {
  73         struct saa7164_buffer *buf = 0;
  74         struct saa7164_dev *dev = port->dev;
  75         int i;
  76
  77         if ((len == 0) || (len >= 65536) || (len % sizeof(u64))) {
  78                 log_warn("%s() SAA_ERR_BAD_PARAMETER\n", __func__);
  79                 goto ret;
  80         }
  81
  82         buf = kzalloc(sizeof(struct saa7164_buffer), GFP_KERNEL);
  83         if (buf == NULL) {
  84                 log_warn("%s() SAA_ERR_NO_RESOURCES\n", __func__);
  85                 goto ret;
  86         }
  87
  88         buf->port = port;
  89         buf->flags = SAA7164_BUFFER_FREE;
  90         /* TODO: arg len is being ignored */
  91         buf->pci_size = SAA7164_PT_ENTRIES * 0x1000;
  92         buf->pt_size = (SAA7164_PT_ENTRIES * sizeof(u64)) + 0x1000;
  93
  94         /* Allocate contiguous memory */
  95         buf->cpu = pci_alloc_consistent(port->dev->pci, buf->pci_size,
  96                 &buf->dma);
  97         if (!buf->cpu)
  98                 goto fail1;
  99
 100         buf->pt_cpu = pci_alloc_consistent(port->dev->pci, buf->pt_size,
 101                 &buf->pt_dma);
 102         if (!buf->pt_cpu)
 103                 goto fail2;
 104
 105         /* init the buffers to a known pattern, easier during debugging */
 106         memset(buf->cpu, 0xff, buf->pci_size);
 107         memset(buf->pt_cpu, 0xff, buf->pt_size);
 108
 109         dprintk(DBGLVL_BUF, "%s()   allocated buffer @ 0x%p\n", __func__, buf);
 110         dprintk(DBGLVL_BUF, "  pci_cpu @ 0x%p    dma @ 0x%08lx len = 0x%x\n",
 111                 buf->cpu, (long)buf->dma, buf->pci_size);
 112         dprintk(DBGLVL_BUF, "   pt_cpu @ 0x%p pt_dma @ 0x%08lx len = 0x%x\n",
 113                 buf->pt_cpu, (long)buf->pt_dma, buf->pt_size);
 114
 115         /* Format the Page Table Entries to point into the data buffer */
 116         for (i = 0 ; i < SAA7164_PT_ENTRIES; i++) {
 117
 118                 *(buf->pt_cpu + i) = buf->dma + (i * 0x1000); /* TODO */
 119
 120         }
 121
 122         goto ret;
 123
 124 fail2:
 125         pci_free_consistent(port->dev->pci, buf->pci_size, buf->cpu, buf->dma);
 126 fail1:
 127         kfree(buf);
 128
 129         buf = 0;
 130 ret:
 131         return buf;
 132 }
 133
 134 int saa7164_buffer_dealloc(struct saa7164_tsport *port,
 135         struct saa7164_buffer *buf)
 136 {
 137         struct saa7164_dev *dev = port->dev;
 138
 139         if ((buf == 0) || (port == 0))
 140                 return SAA_ERR_BAD_PARAMETER;
 141
 142         dprintk(DBGLVL_BUF, "%s() deallocating buffer @ 0x%p\n", __func__, buf);
 143
 144         if (buf->flags != SAA7164_BUFFER_FREE)
 145                 log_warn(" freeing a non-free buffer\n");
 146
 147         pci_free_consistent(port->dev->pci, buf->pci_size, buf->cpu, buf->dma);
 148         pci_free_consistent(port->dev->pci, buf->pt_size, buf->pt_cpu,
 149                 buf->pt_dma);
 150
 151         kfree(buf);
 152
 153         return SAA_OK;
 154 }
 155