From mboxrd@z Thu Jan 1 00:00:00 1970 From: julia@ni.com (Julia Cartwright) Date: Wed, 15 Mar 2017 13:17:30 -0500 Subject: [RFC PATCH 0/4] pinctrl: rockchip: PREEMPT_RT_FULL fixes In-Reply-To: References: <20170313183813.3582-1-john@metanate.com> Message-ID: <20170315181730.GC682@jcartwri.amer.corp.natinst.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Mar 15, 2017 at 02:12:39PM +0100, Linus Walleij wrote: > On Mon, Mar 13, 2017 at 7:38 PM, John Keeping wrote: > > > As described in Documentation/gpio/driver.txt, we should not be using > > sleepable APIs in the irqchip implementation. Since this includes the > > regmap API, this patch series ends up moving the mux setup for IRQs into > > an irq_bus_sync_unlock() handler which may result in the IRQ being > > configured before the port has been muxed as a GPIO. > > > > I've marked the series as RFC because I'm not sure if this is the best > > way to accomplish this or if there is another approach that is cleaner. > > Also, the first patch may not be correct on RK3399 because I originally > > wrote the patch for RK3288 on top of v4.4 where all drive updates only > > affect a single register. We don't need locking in this case because > > regmap_update_bits() takes a lock on the regmap internally, but if these > > two registers need to be updated atomically then another lock will > > be required here - slock cannot be used if it is converted to a raw > > spinlock since with full RT preemption the regmap's spinlock may sleep. > > Nice work! It all looks good to me, let's see what Heiko says. > > Please keep Julia Cartwright on the CC for this patch series, she is > doing some coccinelle-based rewrites to use raw spinlocks as we > speak, and she knows this stuff. > > She has not targeted the Rockchip driver yet, I guess because of > its complexity. I haven't really given much thought to how we might generically solve raw_spinlock problems for those drivers which make of irq_chip_generic just yet. I don't imagine it would be too difficult, just more work. Thanks for the CC. Julia -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 488 bytes Desc: not available URL: