Hi Greg,
Thanks for your reply.
I have done copying memory using a driver to SATA hard drive. Basically by programming SATA Controller registers, doing DMA to write to the sectors of SATA hard drive. Doing this from a User application is completely out of question for my purpose.
Now, I have to do it to a USB Flash Drive or USB Hard Drive. Logically, I think it is only a matter of getting access to device micro-controller (I guess) through USB Host Controller on my PC. I guess programming the USB Host controller should not be a problem (follow EHCI Spec.). But, issuing commands from USB Host Controller to device controller is something that I am not completely sure about.
Will the communication between USB Host Controller and the controller on device follow same standard for all USB Flash/Hard drives available today?
(like UASP or Bulk Only Transpot etc.)
Thanks
Santhosh
--- On Fri, 6/18/10, Greg KH <greg@xxxxxxxxx> wrote:
> From: Greg KH <greg@xxxxxxxxx>
> Subject: Re: USB Mass Storage Driver Question
> To: "S I" <devicedriver72@xxxxxxxxx>
> Cc: linux-usb@xxxxxxxxxxxxxxx
> Date: Friday, June 18, 2010, 9:21 PM
> On Fri, Jun 18, 2010 at 02:03:31PM
> -0700, S I wrote:
> > Hi,
> > I want to write a driver to copy some of the main
> memory contents to a
> > USB Drive (either a USB Flash drive or USB Hard Disk
> Drive). This
> > needs to be done for Windows, Linux and Mac OS X. So,
> I don't want to
> > use the respective kernel based APIs or framework.
>
> Then just use the filesystem interface that all of those
> operating
> systems provides to write to the device.
>
> > I browsed through the EHCI spec (at Intel Site) and
> USB Mass Stroage
> > specs (at USB.org site). EHCI spec talks about setting
> up an
> > Asychronous Schedule for bulk transfers.
>
> Woah, no, you can't talk directly to the ehci controller
> and not expect
> to be writing a kernel driver.
>
> At the worse case, just use libusb, that works on all of
> those operating
> systems you referred to.
>
> Again, just write to the filesystem from userspace, no
> kernel driver
> needed at all. Don't make it much harder than it
> really needs to be :)
>
> good luck,
>
> greg k-h
>
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