dddvb/docs/octopusnet

OctopusNet
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Hardware:

- SoC Atmel SAM9G45 400MHz ARM 926
  64 MB DRAM
  256 MB NAND flash

- FPGA Lattice ECP3 17
  data flash

- 5 port switch Marvell 88E6175R


The FPGA is connected to the memory bus of the G45 and maps control registers into the memory space
of the G45. This is mainly to control the data flow on the FPGA. Only minimal data can be transferred
(e.g. single sections). Transport streams cannot be transferred to the G45 this way!
The FPGA can receive up to 8 TS from up to 4 Duo-Flex cards. You can also can alternatively connect
CI modules to port 2 and 3 (TAP 3 and 4).

The FPGA is also connected to one of the ports of the gigabit switch.
There are up to 12 channels. Each channel can select one input TS, which is then passed through
a PID filter (8192 bit array) and sent to the switch as a UDP/RTP stream.

The G45 is connected to another port of the switch (but only with 100 MBit)


Booting:

The G45 does not boot from the NAND flash but from the dataflash connected to the FPGA. The G45
does not support error correction for the boot sector and NAND with zero error boot pages
is no longer easily available.
Newer Atmel SoCs support 4-bit error correction in boot ROM but not the G45.

So, the G45 boot looks like this:

- Run a minimal boot rom mapped by the FPGA.
- Boot rom loads a modified bootstrap via SPI (provided via FPGA ports) from the dataflash.
- Bootstrap loads u-boot via SPI from dataflash.
- u-boot boots Linux ...

If you remove jumper XX, boot rom is disabled and the G45 will boot from NAND flash like this:

- Internal G45 boot rom bootstrap from NAND flash.
- Bootstrap boots u-boot from NAND flash
- u-boot boots Linux ...

This is just a fall-back since page 0 can contain errors which cannot be corrected by the G45 boot ROM
and the bootstrap code which loads u-boot also does not contain error correction.



- SPI dataflash

0x000000 - 0x003fff FPGA config data
0x004000 - 0x005fff G45 bootstrap
0x010000 - 0x0affff FPGA bitstream
0x0b0000 - 0x15ffff G45 u-boot
0x160000 - 0x1fefff FPGA golden image
0x1ff000 - 0x1fffff FPGA jump to golden image


- NAND flash 256MB, block size 128K (0x20000)

0x00000000 - 0x0001ffff G45 bootstrap (fallback bootstrap if SPI corrupted, pull jumper to use)
0x00020000 - 0x0007ffff G45 u-boot (fallback u-boot if SPI corrupted)
0x00080000 - 0x0009ffff spare (e.g. for bigger u-boot)
0x000a0000 - 0x000bffff G45 u-boot environment
0x000c0000 - 0x000dffff G45 u-boot redundant environment
0x000e0000 - 0x000fffff spare
0x00100000 - 0x01ffffff G45 Linux recovery
0x02000000 - 0x0fffffff Linux UBI