75XX SD: Difference between revisions

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The SD card access is implemented in userspace by acting as an NBD server.  The [[sdctl]] page which will show more advanced usage and the linuxrc script will bring up the nbd-clients in this layout:
This product contains our SD controller implemented in the FPGA.  This will support both SD and SDHC cards so sizes up to 32GB are supported.  The SD card access is implemented in userspace by acting as an NBD server.  The [[sdctl]] page which will show more advanced usage and the linuxrc script will bring up the nbd-clients in this layout:


   /dev/nbd5 - whole disk device of microSD card
   /dev/nbd5 - whole disk device of microSD card
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{{Note|NBD devices do '''not''' report size correctly.  If you are formatting a partition or using dd you will need to specify the size of the underlying block device or partition.}}
{{Note|NBD devices do '''not''' report size correctly.  If you are formatting a partition or using dd you will need to specify the size of the underlying block device or partition.}}
The SD card core is a black box serviced by the [ftp://ftp.embeddedarm.com/ts-arm-sbc/ts-7500-linux/sources/sdcore2.c OS independent C API] for reading/writing SD cards. This source code is available, but not recommended for modification. Since this core instance not cannot use memory based register access the generic peek/poke routines need to be overloaded with SBUS specific register access. This happens automatically in the [ftp://ftp.embeddedarm.com/ts-arm-sbc/ts-7500-linux/sources/sdctl.c sdctl utility] which may be consulted as the reference implementation.

Revision as of 16:11, 29 August 2012

This product contains our SD controller implemented in the FPGA. This will support both SD and SDHC cards so sizes up to 32GB are supported. The SD card access is implemented in userspace by acting as an NBD server. The sdctl page which will show more advanced usage and the linuxrc script will bring up the nbd-clients in this layout: 

 /dev/nbd5 - whole disk device of microSD card
 /dev/nbd6 - 1st partition of SD card (Windows VFAT filesystem on devkit card)
 /dev/nbd7 - 2nd partition of SD card (kernel partition on devkit card)
 /dev/nbd8 - 3rd partition of SD card (EXT2 initrd partition on devkit card)
 /dev/nbd9 - 4th partition of SD card (Debian EXT3 filesystem on devkit card)
Note: NBD devices do not report size correctly. If you are formatting a partition or using dd you will need to specify the size of the underlying block device or partition.
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