From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Mundt Date: Tue, 15 Jul 2008 08:58:01 +0000 Subject: Re: Several questions about SH PCI Message-Id: <20080715085801.GA23440@linux-sh.org> List-Id: References: <7b5883fc0807101148g601033e3n4f9ec4a53ed628fa@mail.gmail.com> In-Reply-To: <7b5883fc0807101148g601033e3n4f9ec4a53ed628fa@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sh@vger.kernel.org On Thu, Jul 10, 2008 at 09:48:41PM +0300, Roni Feldman wrote: > 1. In arch/sh/driver/pci/pci-sh7751.c, shouldn't sh7751_pci_init() be > tagged as core_initcall and not subsyss_initcall? pcibios_init(), > which scans the bus (and expects the pcic to be already initialized) > is also tagged as subsys_initcall. This might lead to bad ordering in > case more things are introduced in the subsys section, since there's > no order guarantee for functions in the same section, right? > It's link order dependent, but yes, there's a potential issue here if we start out with the PCIC completely disabled at boot time. > 2. I didn't manage to find PCIDMA support in the kernel. Did I > overlook it or is it just something nobody has implemented yet for sh? > It's not been implemented. Feel free to send patches. > 3. I was thinking about the case where I'm using non-DMA PCI access, > and I need to change my window (PCIMBR or PCIIOBR). In that case every > section that changes the MBR / IOBR and does PCI access need to be > enclosed in something like pci_lock() and pci_unlock(), to solve the > problem of some other task changing MBR in my "critical section". > Would spinlocks be the best way to implement these locks? > Yes.