From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Boyer Subject: Re: [PATCH] m68k/mac: Allocate IOP message pool and queues dynamically Date: Mon, 1 Jul 2013 15:48:54 -0700 Message-ID: <20130701224854.GB12663@cynthia.pants.nu> References: <1372586542-1318-1-git-send-email-geert@linux-m68k.org> <20130701065258.GA8425@cynthia.pants.nu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Finn Thain Cc: Geert Uytterhoeven , linux-m68k@lists.linux-m68k.org, linux-kernel@vger.kernel.org On Mon, Jul 01, 2013 at 05:48:22PM +1000, Finn Thain wrote: > > On Sun, 30 Jun 2013, Brad Boyer wrote: > > > On Sun, Jun 30, 2013 at 12:02:22PM +0200, Geert Uytterhoeven wrote: > > > > > > if (iop_scc_present) { > > > printk("IOP: detected SCC IOP at %p\n", iop_base[IOP_NUM_SCC]); > > > + alloc_msg_queue(IOP_NUM_SCC); > > > > Technically, this isn't actually useful. As long as we never start this > > IOP, it can't ever send or be sent any messages. > > That assumes that the SCC IOP is in a stopped state after iop_preinit(). > But I don't think that's the case. If it is technically possible to > exchange messages with a device in bypass mode (?) then I think the code > above is correct. You're right. The value we write during iop_preinit actually leaves the IOP running. I'm not sure why we did that. I wonder if it's possible to put the ISM IOP into bypass mode and still use the ADB driver. Then we could possibly use the normal SWIM driver on these systems. > > > @@ -315,6 +307,9 @@ void __init iop_register_interrupts(void) > > > } else { > > > printk("IOP: the ISM IOP seems to be alive.\n"); > > > } > > > > The if/else above isn't useful if it is run before the call to > > iop_start. However, it's also useless if it is called immediately after > > the call to iop_alive which is now below. It was supposed to eventually > > be called in the background on a regular schedule, but that never > > happened. > > > > I agree. That if/else statement and the conditional printk's should be > omitted. > > I had thought that in the existing code the interrupt service routine was > registered before the call to iop_start() but in fact iop_start() happens > first. Looks like a bug to me. The interrupt handler needs to be able to > acknowledge unsolicited messages... Yes, we definitely should install the IRQ handler before calling iop_start. Brad Boyer flar@allandria.com