====== Voipac PXA270 Baseboard ======

  * http://www.voipac.com/ 
  * [[http://www.lancesimms.com/PXA270Tips.html|Marvell PXA270 and ARM Microprocessor Tips]]

{{equipment:embedded:voipac_pxa270_27m-dmm-144_l.jpg?200|}} {{equipment:embedded:voipac_pxa270_27m-dmm-144_l_b.jpg?200|}}

{{ :equipment:embedded:voipac-pxa270-src.zip |}}

{{ :equipment:embedded:voipac-pxa270-docs.zip |}}

{{ :equipment:embedded: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

===== buildroot config =====
make menuconfig
<code>
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)  ---> 
</code>

make uclibc-menuconfig
<code>
Target Architecture Features and Options
  [*]   Target CPU has a floating point unit (FPU)
Networking Support
  [*]     Remote Procedure Call (RPC) support
</code>

make linux-menuconfig



==== Приотритеты каналов ====
^Set ^Channels ^Priority ^Number of Times Served^
|  0  | 0, 1, 2, 3, 16, 17, 18, 19  |  I (High)  |  4/8  |
|  1  | 4, 5, 6, 7, 20, 21, 22, 23  |  II  |  2/8  | 
|  2  | 8, 9, 10, 11, 24, 25, 26, 27 |  III  |  1/8  |
|  3  | 12, 13, 14, 15, 28, 29, 30, 31 |  IV  |  1/8  |

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

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.

---
===== Под Linux =====
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.