From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sandelman.ca (client-ip=209.87.249.19; helo=tuna.sandelman.ca; envelope-from=mcr@sandelman.ca; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=sandelman.ca X-Greylist: delayed 408 seconds by postgrey-1.36 at bilbo; Fri, 10 Jan 2020 14:47:33 AEDT Received: from tuna.sandelman.ca (tuna.sandelman.ca [209.87.249.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 47v87n4bV9zDqbG for ; Fri, 10 Jan 2020 14:47:31 +1100 (AEDT) Received: from sandelman.ca (obiwan.sandelman.ca [IPv6:2607:f0b0:f:2::247]) by tuna.sandelman.ca (Postfix) with ESMTP id DC6BC3897D; Thu, 9 Jan 2020 22:39:43 -0500 (EST) Received: from localhost (localhost [IPv6:::1]) by sandelman.ca (Postfix) with ESMTP id 06A3E104F; Thu, 9 Jan 2020 22:40:06 -0500 (EST) From: Michael Richardson To: "Andrew Jeffery" cc: "Sharad Khetan" , "Vijay Khemka" , rgrs , "openbmc\@lists.ozlabs.org" Subject: Re: MCTP over PCI on AST2500 In-Reply-To: <8a1fc80f-9d25-4c38-bdcd-df05c4194fe7@www.fastmail.com> References: <037D4669-D49C-4DF8-B49B-4F3BD97451AE@fb.com> <865C376D1B77624AAA570EFEF73CE52F9E08757B@fmsmsx118.amr.corp.intel.com> <3502e928-40c5-41d9-9ff1-5aa199e0e31b@www.fastmail.com> <865C376D1B77624AAA570EFEF73CE52F9E0E4E3E@fmsmsx118.amr.corp.intel.com> <8a1fc80f-9d25-4c38-bdcd-df05c4194fe7@www.fastmail.com> X-Mailer: MH-E 8.6; nmh 1.7+dev; GNU Emacs 24.5.1 X-Face: $\n1pF)h^`}$H>Hk{L"x@)JS7<%Az}5RyS@k9X%29-lHB$Ti.V>2bi.~ehC0; <'$9xN5Ub# z!G,p`nR&p7Fz@^UXIn156S8.~^@MJ*mMsD7=QFeq%AL4m X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 Jan 2020 03:47:34 -0000 --=-=-= Content-Type: text/plain Andrew Jeffery wrote: > On Sat, 21 Dec 2019, at 10:45, Khetan, Sharad wrote: >> Hi Andrew, >> Sorry for late response. >> The plan is to have MCTP in user space. >> > How are you handling this then? mmap()'ing the BAR from sysfs? > I plan to get back to implementing in-kernel socket-based MCTP shortly. > Unfortunately it slipped back a little in my priority list late last year. I'd be > interested in your feedback on the proposal when I get something written > down. I have read through a few MCTP documents on dtmf.org, but they either dealt with too highlevel (SMBIOS tables), or too low-level (MCTP over UART). Is there something that I can read that explains the underlying PCI relationships between the BMC and the host CPU's PCI/bridges? Maybe I just need to read the AST2500 datasheet? (I was at one point quite knowledgeable about PCI, having designed adapter cards with multiple targets and dealt with swizzling, and BARs, etc.) What I heard is that for typical AST2500 based BMCs, the host CPU can map the entire address space of the AST2500, and this rather concerns me. I had rather expected some kind of mailbox system in a specialized ram that both systems could use to exchange data. -- ] Never tell me the odds! | ipv6 mesh networks [ ] Michael Richardson, Sandelman Software Works | IoT architect [ ] mcr@sandelman.ca http://www.sandelman.ca/ | ruby on rails [ --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEbsyLEzg/qUTA43uogItw+93Q3WUFAl4X8hUACgkQgItw+93Q 3WXKLgf+Pmgu9jVdkV+wD7Al5VRMM5o6xM3C1vD/b1hxPkEefGy77h0x3xVijYhe zl1iBAxbwUgP73TkYSrzSbWMVh8BZ25nJ2NZhrKUqtcB2QWkT5gCGqhPO2BLqEyz MCMAwKYO5xAjya3F/cIJgZRJ0LDOw6huFF7+XqvJQbzYWcHsvxGGFHnqVRf+qRK2 l87o0o/qc0H7G4YuTCo6/M5rOTQvHPw74MR38yb4sNXoqEZ9/Q6xlGka0pyFYFkt 7dX64fXHioV4xCoZmlyo9p+SdiaivUtuEX8NtRw55iX+lfGwGDp8f+mjLZtAi7T1 5EldMGipN1Zp2MDgIALHtfyHyftXRw== =nfy3 -----END PGP SIGNATURE----- --=-=-=--