On Tue, Jul 08, 2014 at 01:26:26AM +0530, Jeshwanth Kumar N K wrote: > Hi Greg, > > Thanks for the reply. > > I recently purchased an mbed board > https://mbed.org/platforms/mbed-LPC1768/ ;(friend recommended) to learn > USB Mass storage class. And used OpenLPC usb stack with fatfs example > to check how it works (used protocol analyser and stuff, to know whats > happening). In that they are reading each buffer, i mean copying > buffer (8k) of data to RAM and process it. And other idea I found is > using diskio function in openLPC stack to read the data in USB flash > (but this is without file system). The USB storage protocol does not define a specific filesystem, so you can send "raw" block commands to the device, but that's usually not very interesting. > As a Linux user I knew in Linux we can do mmap easily for a file (with > filesystem). So thought of asking from where to start understanding > these concepts :). mmap on a file on disk is the same as USB flash, a USB storage device is just a SCSI device (a quite complex little device, not a trivial one at all.) As I said, you have a filesystem, block layer, SCSI layer, USB layer, and then the VFS and other stuff going on here. So I'd recommend focusing on one layer at a time, otherwise you will be overwhelmed. good luck, greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
