From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from top.free-electrons.com ([176.31.233.9]:52162 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752084AbaAWLyR (ORCPT ); Thu, 23 Jan 2014 06:54:17 -0500 Date: Thu, 23 Jan 2014 08:54:33 -0300 From: Ezequiel Garcia To: Sebastian Hesselbarth Cc: Jason Gunthorpe , linux-arm-kernel@lists.infradead.org, linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org, Lior Amsalem , Thomas Petazzoni , Jason Cooper , Tawfik Bayouk , Andrew Lunn , Wim Van Sebroeck , Gregory Clement Subject: Re: [PATCH v2 06/15] watchdog: orion: Remove unneeded BRIDGE_CAUSE clear Message-ID: <20140123115432.GC6065@localhost> References: <1390295561-3466-1-git-send-email-ezequiel.garcia@free-electrons.com> <1390295561-3466-7-git-send-email-ezequiel.garcia@free-electrons.com> <20140121233537.GS18269@obsidianresearch.com> <20140122164904.GB27273@localhost> <20140122173417.GT18269@obsidianresearch.com> <52E02AB6.7040104@gmail.com> <20140122205213.GW18269@obsidianresearch.com> <52E0591E.6030009@gmail.com> <20140123111049.GB6065@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: QUOTED-PRINTABLE In-Reply-To: <20140123111049.GB6065@localhost> Sender: linux-watchdog-owner@vger.kernel.org List-Id: linux-watchdog@vger.kernel.org Sebastian, On Thu, Jan 23, 2014 at 08:10:49AM -0300, Ezequiel Garcia wrote: > On Thu, Jan 23, 2014 at 12:49:50AM +0100, Sebastian Hesselbarth wrote= : > [..] > > > Notice that Ezequiel has added an IRQ handler that just calls pan= ic, > > > so a spurious interrupt call is VERY VERY BAD. > >=20 > > And I understand that he now clears watchdog's register before > > requesting an irq. All that is missing is bridge_irq driver clearin= g > > CAUSE register after masking all irqs, right? > >=20 >=20 > Are you sure clearing the CAUSE register after masking the IRQs will = be enough? >=20 > AFAICS, until now nobody unmasks the watchdog IRQ (at least the orion= _wdt > driver didn't request the interruption) but *still* the CAUSE registe= r is set > upon watchdog expiration. So I would guessed a masked interrupt still= raises a > bit in the CAUSE register. >=20 Let me add some real information instead of my speculations. Taken from the Kirkwood specification: Table 136: Mbus-L to Mbus Bridge Interrupt Mask Register Offset: 0x00020114 =46ield: Mask Type/InitVal: RW 0x0 Description: There is a mask bit per each cause bit. Mask only affects = the assertion of interrupt pins. It does not affect the setting of bits in the Cause register. So I guess this is why Jason has been insisting with the introduction o= f the irq_startup. (Just for reference, the little patch I attached yesterday proved to wo= rk here.) --=20 Ezequiel Garc=C3=ADa, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-watchdo= g" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html