• http://www.voipac.com/
• Marvell PXA270 and ARM Microprocessor Tips

voipac-pxa270-src.zip

voipac-pxa270-docs.zip

voipac-pxa270-bin.zip

PXA270M DIMM Module Basic specification:

• PXA270M / 312MHz
• 64MB NAND Flash (16bit)
• 64MB SDRAM (32bit)
• Audio AC'97 with controller and support for touchscreen
• 10/100 Mbps Ethernet
• 121 GPIOs
• 200pin SODIMM connector
• JTAG connector pads
• Power supply 3.3V with flexible PMIC
• Dimensions 67.6 x 38.0mm
• 0°C to +70°C commercial temperature range

PXA270M DIMM Module Pro specification:

• PXA270M / 520MHz (by default set to 312MHz)
• 128MB NAND Flash (16bit)
• 128MB SDRAM (32bit)
• Audio AC'97 with controller and support for touchscreen
• 10/100 Mbps Ethernet
• 121 GPIOs
• 200pin SODIMM connector
• JTAG connector pads
• Power supply 3.3V with flexible PMIC
• Dimensions 67.6 x 38.0mm
• 0°C to +70°C commercial temperature range

make menuconfig

Target Architecture (arm)
Target Architecture Variant (xscale)
Target ABI (OABI)
Build options
[*] Enable compiler cache
System configuration
  (em5) System hostname
  (ttyS0) Port to run a getty (login prompt) on 
  Baudrate to use (38400)
Filesystem images
[*] jffs2 root filesystem
[*]   Do not use Cleanmarker
Kernel  
  Kernel binary format (zImage)  ---> 

make uclibc-menuconfig

Target Architecture Features and Options
  [*]   Target CPU has a floating point unit (FPU)
Networking Support
  [*]     Remote Procedure Call (RPC) support

make linux-menuconfig

Прошиваем обновленный загрузчик через JTAG.

Удобно это делать на отладочной baseboard: pxa270_dimm_base_board-datasheet.pdf pxa270_dimm_base_board-schematic.pdf

К плате подключаем JLINK, 12V и COM-порт.

На компьютер устанавливаем openocd:

 $ sudo apt install openocd
 $ openocd --version
   Open On-Chip Debugger 0.12.0

Запускаем отладчик с правильным конфигурационным файлом. В разных JLINK сделанных на чипе ftdi может быть по-разному распаян пин RST.

$ openocd -f vpac270_openocd_v0.12.cfg 
Open On-Chip Debugger 0.12.0
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
Info : pxa270.cpu: hardware has 2 breakpoints and 2 watchpoints
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : clock speed 1000 kHz
Info : JTAG tap: pxa270.cpu tap/device found: 0x79265013 (mfg: 0x009 (Intel), part: 0x9265, ver: 0x7)
Info : starting gdb server for pxa270.cpu on 3333
Info : Listening on port 3333 for gdb connections

For a flow-through DMA read/write from/to an internal peripheral, use the following settings for the DMA controller register bits:

Write to device:
DCMDx[FLYBYS] and DCMDx[FLYBYT] = 0
DSADRx[SRCADDR] = memory address
DTADRx[TRGADDR] = internal peripheral address
DCMDx[INCSRCADDR] = 1
DCMDx[INCTRGADDR] = 0
DCMDx[FLOWSRC] = 0
DCMDx[FLOWTRG] = 1

Read to memory:
DCMDx[FLYBYS] and DCMDx[FLYBYT] = 0
DSADRx[SRCADDR] = internal peripheral address
DTADRx[TRGADDR] = memory address
DCMDx[INCSRCADDR] = 0
DCMDx[INCTRGADDR] = 1
DCMDx[FLOWSRC] = 1
DCMDx[FLOWTRG] = 0

All companion-chip-related transfers must use 64-bit aligned addresses for both source and target locations.

Restricting memory addresses to 8-byte boundaries can be helpful because the DMA controller encounters overhead while it works with misaligned data. Align the source and target addresses to 32-byte boundaries for optimal DMA controller and memory controller performance.

By default, during data transfers the DMA controller forces the least significant three bits of all external addresses to zeros and the least significant two bits of all peripheral addresses to zeros. Software must activate the alignment register to activate byte-aligned addressing.

Companion Chip to Memory:

Source Alignment (Bytes) : 8
Target Alignment (Bytes) : 8
DCMD [IncSrcAddr] (Binary) : 0 or 1
DCMD [IncTrgAddr] (Binary) : 1
DCMD[Width] (Binary) : 00

The companion chip or external peripheral must be connected as a variable-latency I/O memory.

If either DCMDx[IncSrcAddr] or DCMDx[IncTrgAddr] is set, then the DMA controller increments the source or target address, after each bursting transaction, by a number equal to the transaction burst size (8, 16 or 32 bytes) or DCMDx[Len]. The latter is used if DCMDx[Len] is less than the burst size.

DCMD_WIDTH must be 0b00 for memory-to-memory moves or companion-chip-related operations.

—

Состояние регистров DMA смотри в debugfs: /debug/pxa_dma/channels/0/state

Большинство полезных функций уже определены в файлах

/arch/arm/plat-pxa/dma.c 
/arch/arm/plat-pxa/include/plat/dma.h

так что изобретать свои велосипеды нет необходимости.