From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Date: Fri, 20 May 2011 08:08:16 +0000 Subject: Re: [PATCH 0/2] sparc32,leon: PCI patches Message-Id: <20110520.040816.1411861187670192730.davem@davemloft.net> List-Id: References: <4DB68838.1020304@gaisler.com> In-Reply-To: <4DB68838.1020304@gaisler.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: sparclinux@vger.kernel.org From: Daniel Hellstrom Date: Fri, 20 May 2011 10:01:11 +0200 > David Miller wrote: > >>From: Daniel Hellstrom >>Date: Thu, 19 May 2011 15:13:14 +0200 >> >> >>>The PowerPC for example assign resources >>>(arch/powerpc/kernel/pci-common.c), and PowerPC may also have a >>>OpenBoot loader: >>> >> >>On some powerpc systems, like sparc64 Niagara, you can't blindly go >>poking around the PCI config space at all and must rely completely >>and entirely upon the OpenBoot device tree. >> > I see, that may be because IRQ routing or resource allocation is done > in a non-standard way I guess, perhaps because of bugs on some of the > motherboards. Or because PCI accesses have to go through a hypervisor. The point is that having it all setup in OpenBoot is a great abstraction because you don't have to care. It also allows things like being able to disable devices with things like "pcia-probe-list" and "pcib-probe-list" properties in the PCI host controller node, which we end up honoring on sparc64 simply because we never directly probe PCI space to probe devices.