From owner-freebsd-hackers Thu Oct 26 07:58:38 1995 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id HAA08793 for hackers-outgoing; Thu, 26 Oct 1995 07:58:38 -0700 Received: from hda.com (hda.com [199.232.40.182]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id HAA08788 for ; Thu, 26 Oct 1995 07:58:33 -0700 Received: (from dufault@localhost) by hda.com (8.6.11/8.6.9) id LAA06118 for hackers@freebsd.org; Thu, 26 Oct 1995 11:01:07 -0400 From: Peter Dufault Message-Id: <199510261501.LAA06118@hda.com> Subject: Physically contig memory in user process To: hackers@freebsd.org Date: Thu, 26 Oct 1995 11:01:06 -0400 (EDT) X-Mailer: ELM [version 2.4 PL24] Content-Type: text Content-Length: 710 Sender: owner-hackers@freebsd.org Precedence: bulk I want to allocate DMA-friendly buffers that are physically contiguous and within the isa space from a user process so that I know I can do DMA into them without going through bounce buffers or splitting up the transfer. I figure I can allocate the memory in the kernel using isa_physmem or something similar; I haven't looked through this completely yet. What should the semantics be from a user process? A new minor number to mmap to in /dev/mem? Maybe with "addr" equal to the value desired for the low bits of the physical address? -- Peter Dufault Real Time Machine Control and Simulation HD Associates, Inc. Voice: 508 433 6936 dufault@hda.com Fax: 508 433 5267