1This document describes the cx2341x memory map and documents some of the register
  2space.
  3
  4Note: the memory long words are little-endian ('intel format').
  5
  6Warning! This information was figured out from searching through the memory and
  7registers, this information may not be correct and is certainly not complete, and
  8was not derived from anything more than searching through the memory space with
  9commands like:
 10
 11	ivtvctl -O min=0x02000000,max=0x020000ff
 12
 13So take this as is, I'm always searching for more stuff, it's a large
 14register space :-).
 15
 16Memory Map
 17==========
 18
 19The cx2341x exposes its entire 64M memory space to the PCI host via the PCI BAR0
 20(Base Address Register 0). The addresses here are offsets relative to the
 21address held in BAR0.
 22
 230x00000000-0x00ffffff Encoder memory space
 240x00000000-0x0003ffff Encode.rom
 25      ???-???         MPEG buffer(s)
 26      ???-???         Raw video capture buffer(s)
 27      ???-???         Raw audio capture buffer(s)
 28      ???-???         Display buffers (6 or 9)
 29
 300x01000000-0x01ffffff Decoder memory space
 310x01000000-0x0103ffff Decode.rom
 32      ???-???         MPEG buffers(s)
 330x0114b000-0x0115afff Audio.rom (deprecated?)
 34
 350x02000000-0x0200ffff Register Space
 36
 37Registers
 38=========
 39
 40The registers occupy the 64k space starting at the 0x02000000 offset from BAR0.
 41All of these registers are 32 bits wide.
 42
 43DMA Registers 0x000-0xff:
 44
 45 0x00 - Control:
 46	0=reset/cancel, 1=read, 2=write, 4=stop
 47 0x04 - DMA status:
 48	1=read busy, 2=write busy, 4=read error, 8=write error, 16=link list error
 49 0x08 - pci DMA pointer for read link list
 50 0x0c - pci DMA pointer for write link list
 51 0x10 - read/write DMA enable:
 52	1=read enable, 2=write enable
 53 0x14 - always 0xffffffff, if set any lower instability occurs, 0x00 crashes
 54 0x18 - ??
 55 0x1c - always 0x20 or 32, smaller values slow down DMA transactions
 56 0x20 - always value of 0x780a010a
 57 0x24-0x3c - usually just random values???
 58 0x40 - Interrupt status
 59 0x44 - Write a bit here and shows up in Interrupt status 0x40
 60 0x48 - Interrupt Mask
 61 0x4C - always value of 0xfffdffff,
 62	if changed to 0xffffffff DMA write interrupts break.
 63 0x50 - always 0xffffffff
 64 0x54 - always 0xffffffff (0x4c, 0x50, 0x54 seem like interrupt masks, are
 65	3 processors on chip, Java ones, VPU, SPU, APU, maybe these are the
 66	interrupt masks???).
 67 0x60-0x7C - random values
 68 0x80 - first write linked list reg, for Encoder Memory addr
 69 0x84 - first write linked list reg, for pci memory addr
 70 0x88 - first write linked list reg, for length of buffer in memory addr
 71	(|0x80000000 or this for last link)
 72 0x8c-0xdc - rest of write linked list reg, 8 sets of 3 total, DMA goes here
 73	from linked list addr in reg 0x0c, firmware must push through or
 74	something.
 75 0xe0 - first (and only) read linked list reg, for pci memory addr
 76 0xe4 - first (and only) read linked list reg, for Decoder memory addr
 77 0xe8 - first (and only) read linked list reg, for length of buffer
 78 0xec-0xff - Nothing seems to be in these registers, 0xec-f4 are 0x00000000.
 79
 80Memory locations for Encoder Buffers 0x700-0x7ff:
 81
 82These registers show offsets of memory locations pertaining to each
 83buffer area used for encoding, have to shift them by <<1 first.
 84
 850x07F8: Encoder SDRAM refresh
 860x07FC: Encoder SDRAM pre-charge
 87
 88Memory locations for Decoder Buffers 0x800-0x8ff:
 89
 90These registers show offsets of memory locations pertaining to each
 91buffer area used for decoding, have to shift them by <<1 first.
 92
 930x08F8: Decoder SDRAM refresh
 940x08FC: Decoder SDRAM pre-charge
 95
 96Other memory locations:
 97
 980x2800: Video Display Module control
 990x2D00: AO (audio output?) control
1000x2D24: Bytes Flushed
1010x7000: LSB I2C write clock bit (inverted)
1020x7004: LSB I2C write data bit (inverted)
1030x7008: LSB I2C read clock bit
1040x700c: LSB I2C read data bit
1050x9008: GPIO get input state
1060x900c: GPIO set output state
1070x9020: GPIO direction (Bit7 (GPIO 0..7) - 0:input, 1:output)
1080x9050: SPU control
1090x9054: Reset HW blocks
1100x9058: VPU control
1110xA018: Bit6: interrupt pending?
1120xA064: APU command
113
114
115Interrupt Status Register
116=========================
117
118The definition of the bits in the interrupt status register 0x0040, and the
119interrupt mask 0x0048. If a bit is cleared in the mask, then we want our ISR to
120execute.
121
122Bit
12331 Encoder Start Capture
12430 Encoder EOS
12529 Encoder VBI capture
12628 Encoder Video Input Module reset event
12727 Encoder DMA complete
12824 Decoder audio mode change detection event (through event notification)
12922 Decoder data request
13020 Decoder DMA complete
13119 Decoder VBI re-insertion
13218 Decoder DMA err (linked-list bad)
133
134Missing
135Encoder API call completed
136Decoder API call completed
137Encoder API post(?)
138Decoder API post(?)
139Decoder VTRACE event