Xref: utzoo comp.unix.microport:1102 comp.unix.wizards:10083 Path: utzoo!attcan!uunet!husc6!rutgers!ucla-cs!sm.unisys.com!ism780c!mikep From: mikep@ism780c.isc.com (Michael A. Petonic) Newsgroups: comp.unix.microport,comp.unix.wizards Subject: Re: How to attach to physical memory Message-ID: <12398@ism780c.isc.com> Date: 27 Jul 88 19:42:16 GMT References: <193@focsys.UUCP> Reply-To: mikep@ism780c.UUCP (Michael A. Petonic) Organization: Interactive Systems Corp., Santa Monica CA Lines: 27 In article <193@focsys.UUCP> larry@focsys.UUCP (Larry Williamson) writes: >How does one get access to a memory buffer that is hard wired to a >physical memory location outside of the normal system memory? > [...] >If I use this technique, I must tell my driver to use a physical memory >buffer, but I do not understand how to tell my driver to read from >physical address 0xa00000. > >I am using Bell Tech's Unix system V/386. > >Thanks, > Larry Since Bell Tech's UNIX system V/386 is close to our's (INTERACTIVE's 386/ix (see various articles describing the ancestry)), I looked in our ``Writing 386/ix Device Drivers'' book and it mentions the macros ``phystokv()'' and ``kvtophys()'' which map between physical addresses and kernel virtual addresses. They are defined in . This should be relevant to Bell Tech's system. -MikeP -------- Michael A. Petonic (213) 453-8649 x3247 INTERACTIVE Systems Corporation "My opinions in no way influence 2401 Colorado Blvd. the price of tea in China." Santa Monica, CA. 90404 {sdcrdcf|attunix|microsoft|sfmin}!ism780c!mikep