From owner-freebsd-current@freebsd.org Tue Apr 25 20:53:31 2017 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 44F50D4F70D for ; Tue, 25 Apr 2017 20:53:31 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from mail.baldwin.cx (bigwig.baldwin.cx [96.47.65.170]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 01BEE1C03; Tue, 25 Apr 2017 20:53:30 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from ralph.baldwin.cx (c-73-231-226-104.hsd1.ca.comcast.net [73.231.226.104]) by mail.baldwin.cx (Postfix) with ESMTPSA id 0CD3910A7DB; Tue, 25 Apr 2017 16:53:29 -0400 (EDT) From: John Baldwin To: Dexuan Cui Cc: "freebsd-current@freebsd.org" , Jung-uk Kim , Yanmin Qiao Subject: Re: Add support for ACPI Module Device ACPI0004? Date: Tue, 25 Apr 2017 13:36:32 -0700 Message-ID: <5144516.9adee9646c@ralph.baldwin.cx> User-Agent: KMail/4.14.10 (FreeBSD/11.0-STABLE; KDE/4.14.10; amd64; ; ) In-Reply-To: References: <3484633.CMRgrtiqef@ralph.baldwin.cx> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.4.3 (mail.baldwin.cx); Tue, 25 Apr 2017 16:53:29 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.99.2 at mail.baldwin.cx X-Virus-Status: Clean X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 25 Apr 2017 20:53:31 -0000 On Thursday, April 20, 2017 02:29:30 AM Dexuan Cui wrote: > > From: John Baldwin [mailto:jhb@freebsd.org] > > Sent: Thursday, April 20, 2017 02:34 > > > Can we add the support of "ACPI0004" with the below one-line change? > > > > > > acpi_sysres_probe(device_t dev) > > > { > > > - static char *sysres_ids[] = { "PNP0C01", "PNP0C02", NULL }; > > > + static char *sysres_ids[] = { "PNP0C01", "PNP0C02", "ACPI0004", NULL }; > > > > > Hmm, so the role of C01 and C02 is to reserve system resources, though we > > in turn allow any child of acpi0 to suballocate those ranges (since historically > > c01 and c02 tend to allocate I/O ranges that are then used by things like the > > EC, PS/2 keyboard controller, etc.). From my reading of ACPI0004 in the ACPI > > 6.1 spec it's not quite clear that ACPI0004 is like that? In particular, it > > seems that 004 should only allow direct children to suballocate? This > > change might work, but it will allow more devices to allocate the ranges in > > _CRS than otherwise. > > > > Do you have an acpidump from a guest system that contains an ACPI0004 > > node that you can share? > > > > John Baldwin > > Hi John, > Thanks for the help! > > Please see the attached file, which is got by > "acpidump -dt | gzip -c9 > acpidump.dt.gz" > > In the dump, we can see the "ACPI0004" node (VMOD) is the parent of > "VMBus" (VMBS). > It looks the _CRS of ACPI0004 is dynamically generated. Though we can't > see the length of the MMIO range in the dumped asl code, it does have > a 512MB MMIO range [0xFE0000000, 0xFFFFFFFFF]. > > It looks FreeBSD can't detect ACPI0004 automatically. > With the above one-line change, I can first find the child device > acpi_sysresource0 of acpi0, then call AcpiWalkResources() to get > the _CRS of acpi_sysresource0, i.e. the 512MB MMIO range. > > If you think we shouldn't touch acpi_sysresource0 here, I guess > we can add a new small driver for ACPI0004, just like we added VMBus > driver as a child device of acpi0? Hmmm, so looking at this, the "right" thing is probably to have a device driver for the ACPI0004 device that parses its _CRS and then allows its child devices to sub-allocate resources from the ranges in _CRS. However, this would mean make VMBus be a child of the ACPI0004 device. Suppose we called the ACPI0004 driver 'acpi_module' then the 'acpi_module0' device would need to create a child device for all of its child devices. Right now acpi0 also creates devices for them which is somewhat messy (acpi0 creates child devices anywhere in its namespace that have a valid _HID). You can find those duplicates and remove them during acpi_module0's attach routine before creating its own child device_t devices. (We associate a device_t with each Handle when creating device_t's for ACPI handles which is how you can find the old device that is a direct child of acpi0 so that it can be removed). Then when you are the "VMBus" device_t your parent is the ACPI0004 device so you can easily talk to it to obtain resources (probably ACPI0004 can just intercept bus_if.m resource methods to manage the resources). -- John Baldwin