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V4L/DVB (5119): Various cx2341x documentation updates/fixes.

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Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Hans Verkuil 2007-01-22 18:27:47 -03:00 committed by Mauro Carvalho Chehab
parent 5cc1dd8c3d
commit a63ad325c3
3 changed files with 18 additions and 12 deletions
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16
Documentation/video4linux/cx2341x/fw-dma.txt
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@ -22,6 +22,8 @@ urged to choose a smaller block size and learn the scatter-gather technique.
Mailbox #10 is reserved for DMA transfer information.
Note: the hardware expects little-endian data ('intel format').
Flow
====
@ -64,7 +66,7 @@ addresses are the physical memory location of the target DMA buffer.
Each S-G array element is a struct of three 32-bit words. The first word is
the source address, the second is the destination address. Both take up the
entire 32 bits. The lowest 16 bits of the third word is the transfer byte
entire 32 bits. The lowest 18 bits of the third word is the transfer byte
count. The high-bit of the third word is the "last" flag. The last-flag tells
the card to raise the DMA_DONE interrupt. From hard personal experience, if
you forget to set this bit, the card will still "work" but the stream will
@ -78,8 +80,8 @@ Array Element:
- 32-bit Source Address
- 32-bit Destination Address
- 16-bit reserved (high bit is the last flag)
- 16-bit byte count
- 14-bit reserved (high bit is the last flag)
- 18-bit byte count
DMA Transfer Status
===================
@ -87,8 +89,8 @@ DMA Transfer Status
Register 0x0004 holds the DMA Transfer Status:
Bit
4 Scatter-Gather array error
3 DMA write error
2 DMA read error
1 write completed
0 read completed
1 write completed
2 DMA read error
3 DMA write error
4 Scatter-Gather array error

10
Documentation/video4linux/cx2341x/fw-encoder-api.txt
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@ -498,12 +498,14 @@ Name CX2341X_ENC_GET_PREV_DMA_INFO_MB_9
Enum 203/0xCB
Description
Returns information on the previous DMA transfer in conjunction with
bit 27 of the interrupt mask. Uses mailbox 9.
bit 27 or 18 of the interrupt mask. Uses mailbox 9.
Result[0]
Status bits:
Bit 0 set indicates transfer complete
Bit 2 set indicates transfer error
Bit 4 set indicates linked list error
0 read completed
1 write completed
2 DMA read error
3 DMA write error
4 Scatter-Gather array error
Result[1]
DMA type
Result[2]

4
Documentation/video4linux/cx2341x/fw-memory.txt
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@ -1,6 +1,8 @@
This document describes the cx2341x memory map and documents some of the register
space.
Note: the memory long words are little-endian ('intel format').
Warning! This information was figured out from searching through the memory and
registers, this information may not be correct and is certainly not complete, and
was not derived from anything more than searching through the memory space with
@ -67,7 +69,7 @@ DMA Registers 0x000-0xff:
0x84 - first write linked list reg, for pci memory addr
0x88 - first write linked list reg, for length of buffer in memory addr
(|0x80000000 or this for last link)
0x8c-0xcc - rest of write linked list reg, 8 sets of 3 total, DMA goes here
0x8c-0xdc - rest of write linked list reg, 8 sets of 3 total, DMA goes here
from linked list addr in reg 0x0c, firmware must push through or
something.
0xe0 - first (and only) read linked list reg, for pci memory addr