Re: Write/Read Bulk communication process in KEXT. How?
Re: Write/Read Bulk communication process in KEXT. How?
- Subject: Re: Write/Read Bulk communication process in KEXT. How?
- From: Chinki <email@hidden>
- Date: Wed, 24 May 2006 09:09:50 +0530
Hi Garth,
Thanks for your mail.
I had already searched the APPLE website and old archives but there is no sample provided.
Believe me, but its truth that there are several queries for the same question. But no straight solution.
Can ANY BODY FROM YOUR TEAM post a simple straight method how to use IOMemoryDescriptor to write / read data.
The bulk write/read at USER-LEVEL framework is QUITE EASY. But at kernel level it is mentioned Write / Read take a pointer to IOMemoryDescriptor and its no where described how to exactly fill this structure.
What needs to filled in this IOMemoryDescriptor ?What are the steps ? At Write function , Apple documentation tells nothing about the same.
After reading the documenation, i could get just the rough idea :
1. Use prepare() to make sure that physical memory is availabefor i/o transfer
2. Use writebytes/readbytes
3. Give the direction, kDirectionOut or kDirectionIn
4. Do i/o
5. complete() unwire the memory
But I am not sure if the above steps are correct.
So i would request again to atleast give the exact path incase you have some simple example at your end. And if its not availalbe, then plz atleast paste a simple steps for the same,
Thanks in advance,
Chinki
On 5/23/06, Garth Cummings <email@hidden> wrote:
On May 23, 2006, at 6:53 AM, Chinki wrote:
> Hello all,
>
> Greetings!!!
>
> Upon searching the archives, I found out that although this
> question has been posted but there has been NO Answer for the same
> till date.
>
>
> I need to bulk write/read through my IO Driver (kext). Can any one
> explain how to use IOMemoryDescriptor ? Any sample example that
> illustrates the very simple communication.
It sounds like you might not be aware of the existence of the Apple
Developer reference library. I highly recommend you start at <http://
developer.apple.com/referencelibrary> and use the search engine on
those pages to find what you're looking for.
The reference library includes developer documentation, technical
notes, sample code, and technical Q&As.
This information is also on your Mac OS X machine at /Developer/ADC
Reference Library if you have the development tools installed.
You might also want to review the mailing list guidelines at <http://
lists.apple.com>. Note particularly the statement "While Apple
employees monitor the lists, Apple doesn't guarantee that questions
will be answered. The mailing lists are not a replacement for formal
support or bug reporting procedures."
If you need help beyond what the documentation and sample code
provides, you can also make use of Apple Developer Technical Support.
You can read more about this program at the URL in my email signature.
Best wishes,
--gc
____________________________________________________________________
Garth Cummings email@hidden
Sr. Software Engineer
Apple Developer Technical Support
<http://developer.apple.com/technicalsupport>
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