[media] cx2341x.rst: add contents of fw-memory.txt

Convert the content to ReST and add it at the cx231xx.rst
file.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 151 insertions, 0 deletions

diff --git a/Documentation/media/v4l-drivers/cx2341x.rst b/Documentation/media/v4l-drivers/cx2341x.rst
index ca2f15c..ed7e536 100644
--- a/Documentation/media/v4l-drivers/cx2341x.rst
+++ b/Documentation/media/v4l-drivers/cx2341x.rst
@@ -1,6 +1,157 @@
 The cx2341x driver
 ==================
 
+Memory at cx2341x chips
+-----------------------
+
+This section 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 commands like:
+
+	.. code-block:: none
+
+		ivtvctl -O min=0x02000000,max=0x020000ff
+
+	So take this as is, I'm always searching for more stuff, it's a large
+	register space :-).
+
+Memory Map
+~~~~~~~~~~
+
+The cx2341x exposes its entire 64M memory space to the PCI host via the PCI BAR0
+(Base Address Register 0). The addresses here are offsets relative to the
+address held in BAR0.
+
+.. code-block:: none
+
+	0x00000000-0x00ffffff Encoder memory space
+	0x00000000-0x0003ffff Encode.rom
+	???-???         MPEG buffer(s)
+	???-???         Raw video capture buffer(s)
+	???-???         Raw audio capture buffer(s)
+	???-???         Display buffers (6 or 9)
+
+	0x01000000-0x01ffffff Decoder memory space
+	0x01000000-0x0103ffff Decode.rom
+	???-???         MPEG buffers(s)
+	0x0114b000-0x0115afff Audio.rom (deprecated?)
+
+	0x02000000-0x0200ffff Register Space
+
+Registers
+~~~~~~~~~
+
+The registers occupy the 64k space starting at the 0x02000000 offset from BAR0.
+All of these registers are 32 bits wide.
+
+.. code-block:: none
+
+	DMA Registers 0x000-0xff:
+
+	0x00 - Control:
+		0=reset/cancel, 1=read, 2=write, 4=stop
+	0x04 - DMA status:
+		1=read busy, 2=write busy, 4=read error, 8=write error, 16=link list error
+	0x08 - pci DMA pointer for read link list
+	0x0c - pci DMA pointer for write link list
+	0x10 - read/write DMA enable:
+		1=read enable, 2=write enable
+	0x14 - always 0xffffffff, if set any lower instability occurs, 0x00 crashes
+	0x18 - ??
+	0x1c - always 0x20 or 32, smaller values slow down DMA transactions
+	0x20 - always value of 0x780a010a
+	0x24-0x3c - usually just random values???
+	0x40 - Interrupt status
+	0x44 - Write a bit here and shows up in Interrupt status 0x40
+	0x48 - Interrupt Mask
+	0x4C - always value of 0xfffdffff,
+		if changed to 0xffffffff DMA write interrupts break.
+	0x50 - always 0xffffffff
+	0x54 - always 0xffffffff (0x4c, 0x50, 0x54 seem like interrupt masks, are
+		3 processors on chip, Java ones, VPU, SPU, APU, maybe these are the
+		interrupt masks???).
+	0x60-0x7C - random values
+	0x80 - first write linked list reg, for Encoder Memory addr
+	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-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
+	0xe4 - first (and only) read linked list reg, for Decoder memory addr
+	0xe8 - first (and only) read linked list reg, for length of buffer
+	0xec-0xff - Nothing seems to be in these registers, 0xec-f4 are 0x00000000.
+
+Memory locations for Encoder Buffers 0x700-0x7ff:
+
+These registers show offsets of memory locations pertaining to each
+buffer area used for encoding, have to shift them by <<1 first.
+
+- 0x07F8: Encoder SDRAM refresh
+- 0x07FC: Encoder SDRAM pre-charge
+
+Memory locations for Decoder Buffers 0x800-0x8ff:
+
+These registers show offsets of memory locations pertaining to each
+buffer area used for decoding, have to shift them by <<1 first.
+
+- 0x08F8: Decoder SDRAM refresh
+- 0x08FC: Decoder SDRAM pre-charge
+
+Other memory locations:
+
+- 0x2800: Video Display Module control
+- 0x2D00: AO (audio output?) control
+- 0x2D24: Bytes Flushed
+- 0x7000: LSB I2C write clock bit (inverted)
+- 0x7004: LSB I2C write data bit (inverted)
+- 0x7008: LSB I2C read clock bit
+- 0x700c: LSB I2C read data bit
+- 0x9008: GPIO get input state
+- 0x900c: GPIO set output state
+- 0x9020: GPIO direction (Bit7 (GPIO 0..7) - 0:input, 1:output)
+- 0x9050: SPU control
+- 0x9054: Reset HW blocks
+- 0x9058: VPU control
+- 0xA018: Bit6: interrupt pending?
+- 0xA064: APU command
+
+
+Interrupt Status Register
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The definition of the bits in the interrupt status register 0x0040, and the
+interrupt mask 0x0048. If a bit is cleared in the mask, then we want our ISR to
+execute.
+
+- bit 31 Encoder Start Capture
+- bit 30 Encoder EOS
+- bit 29 Encoder VBI capture
+- bit 28 Encoder Video Input Module reset event
+- bit 27 Encoder DMA complete
+- bit 24 Decoder audio mode change detection event (through event notification)
+- bit 22 Decoder data request
+- bit 20 Decoder DMA complete
+- bit 19 Decoder VBI re-insertion
+- bit 18 Decoder DMA err (linked-list bad)
+
+Missing documentation
+---------------------
+
+- Encoder API post(?)
+- Decoder API post(?)
+- Decoder VTRACE event
+
+
 How to call the firmware API
 ----------------------------