From owner-freebsd-hackers  Thu Mar  7 14:28: 5 2002
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Date: Thu, 07 Mar 2002 15:27:47 -0700 (MST)
Message-Id: <20020307.152747.127669206.imp@village.org>
To: valery.khromov@icluk.com
Cc: freebsd-hackers@FreeBSD.ORG
Subject: Re: Converting physical into virtual address
From: "M. Warner Losh" <imp@village.org>
In-Reply-To: <009c01c1c356$93e13be0$c80ca8c0@khromovv>
References: <009c01c1c356$93e13be0$c80ca8c0@khromovv>
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In message: <009c01c1c356$93e13be0$c80ca8c0@khromovv>
            "Valery N. Khromov" <valery.khromov@icluk.com> writes:
: I'd like to develop a kernel module for FreeBSD, able to read & write
: directly to VGA text-mode screen buffer. I know that this buffer is located
: at 0xB8000 in physical address space. But in kernel I must address it using
: kernel virtual address space.
: 
: Thus, the question is: how can I _correctly_ convert physical address into
: kernel virtual address?
: 
: Now I use the following trick: 0xC0000000 + 0xB8000, but I want to use more
: correct method. :)

bus_alloc_resource() followed by bus_space_{read,write}_*.

Warner

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