From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Mundt Date: Wed, 27 Feb 2013 08:52:17 +0000 Subject: Re: [PATCH] irqchip: Renesas INTC External IRQ pin driver Message-Id: <20130227085216.GC30395@linux-sh.org> List-Id: References: <20130218142834.28739.39417.sendpatchset@w520> <20130227082335.GB30395@linux-sh.org> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Magnus Damm Cc: linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org, benh@kernel.crashing.org, grant.likely@secretlab.ca, horms@verge.net.au, tglx@linutronix.de On Wed, Feb 27, 2013 at 05:35:51PM +0900, Magnus Damm wrote: > On Wed, Feb 27, 2013 at 5:23 PM, Paul Mundt wrote: > > So how exactly does this interact with the existing sh_intc code? Or is > > there some reason why you have opted to bypass it in order to implement a > > simplified reduced-functionality version of INTC support focused only on > > external pins? If both are used together this is going to be a nightmare > > for locking, and it's also non-obvious how the IRQ domains on both sides > > will interact. > > > > This needs a lot more explanation. > > Recent GIC-based SoCs do not make use of INTC for any on-chip I/O > devices. This driver is meant to be used as a layer between the actual > IRQ pin and the GIC. Anything else needs the full driver. The existing > non-DT INTC driver can happily coexist with this driver like it does > in the case of sh73a0 here: > > [PATCH 02/03] ARM: shmobile: INTC External IRQ pin driver on sh73a0 > Ok, thanks for clarifying. I suppose the main concern is how quickly this will simply turn in to a deviated partial implementation of the full driver as newer SoCs begin deviating from your simplified case, and we basically end up reimplementing sh_intc anyways. > The driver is not meant to be used with INTC-only based systems like > sh7372 and the SH architecture. I would be very happy if someone could > get their shit together and fix up DT support for the common INTC > code. This has not happened yet though. So if you know anyone with > time to spare then feel free to suggest them to work together with > Iwamatsu-san to get the DT version of the code reviewed together with > Linaro. > I haven't heard or seen anything new on that in some time, so I assumed the work had stalled. I'm not sure why there wasn't more effort put in to DT support for the INTC code rather than simply coming up with a temporary bypass shim, and I'm not sure why you think this work is blocked by anyone (unless you're just referring to a general lack of resources). In any event, I'm not sure what the best option for the interim is. I suppose we can merge the irqchips until the INTC stuff catches up, but then we are probaby going to run in to a situation where they either have to co-exist, or the irqchips are removed and the sh_intc code has to carry a compat shim to deal with those DT bindings. Neither of those options seem particularly appealing to me.