From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris.brezillon@free-electrons.com (Boris Brezillon) Date: Wed, 14 Jan 2015 09:31:30 +0100 Subject: [PATCH v2 1/5] irqchip: add dumb demultiplexer implementation In-Reply-To: References: <1421174781-4340-1-git-send-email-boris.brezillon@free-electrons.com> <1421174781-4340-2-git-send-email-boris.brezillon@free-electrons.com> Message-ID: <20150114093130.3923a89a@bbrezillon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Thomas, On Tue, 13 Jan 2015 22:00:55 +0100 (CET) Thomas Gleixner wrote: > On Tue, 13 Jan 2015, Boris Brezillon wrote: > > + ret = irq_set_handler_data(irq, demux); > > + if (ret) { > > + pr_err("Failed to assign handler data\n"); > > + goto err_free_domain; > > + } > > + > > + irq_set_chained_handler(irq, irq_dumb_demux_handler); > > + > > + /* > > + * Disable the src irq (automatically enabled by > > + * irq_set_chained_handler) to prevent irqs from happening while > > + * nobody requested any of the demuxed irqs. > > + */ > > + disable_irq(irq); > > We rather prevent the startup of the irq line right away. Yep, the comment was here to draw the attention, since I wasn't sure modifying core code was the best solution. Anyway I agree that keeping the src_irq disabled when registering the chained handler is better than doing it afterwards. > > enum { > IRQ_CHAINED_NONE, > IRQ_CHAINED_STARTUP, > IRQ_CHAINED_NOSTARTUP, > }; > > -__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained, > - const char *name); > +__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int chained_mode, > + const char *name); > > { > .... > if (handle != handle_bad_irq && chained_mode) { > irq_settings_set_noprobe(desc); > irq_settings_set_norequest(desc); > irq_settings_set_nothread(desc); > - irq_startup(desc, true); > + if (chained_mode == IRQ_CHAINED_STARTUP) > + irq_startup(desc, true); > } > .... > } > > Hmm? I'm fine with this approach, with a static inline helper: static inline void irq_set_chained_handler_nostartup(unsigned int irq, irq_flow_handler_t handle) { __irq_set_handler(irq, handle, IRQ_CHAINED_NOSTARTUP, NULL); } Anyway, I'll wait a clear decision regarding which approach should be taken (see my answer to Rob) before sending a new version. Thanks for your reviews. Best Regards, Boris -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com