From mboxrd@z Thu Jan 1 00:00:00 1970 From: pratheesh@ti.com (TK, Pratheesh Gangadhar) Date: Mon, 21 Feb 2011 09:27:47 +0530 Subject: [PATCH 1/2] PRUSS UIO driver support In-Reply-To: <20110219183427.GG4684@local> References: <1298041530-26855-1-git-send-email-pratheesh@ti.com> <201102181644.17634.arnd@arndb.de> <201102181731.05644.arnd@arndb.de> <20110219183427.GG4684@local> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Hans, > -----Original Message----- > From: Hans J. Koch [mailto:hjk at hansjkoch.de] > Sent: Sunday, February 20, 2011 12:04 AM > To: TK, Pratheesh Gangadhar > Cc: Thomas Gleixner; Arnd Bergmann; linux-arm-kernel at lists.infradead.org; > davinci-linux-open-source at linux.davincidsp.com; gregkh at suse.de; > Chatterjee, Amit; Hans J. Koch; LKML > Subject: Re: [PATCH 1/2] PRUSS UIO driver support > > On Sat, Feb 19, 2011 at 09:10:23PM +0530, TK, Pratheesh Gangadhar wrote: > > > > For my understanding - if the interrupt is not shared and not level > triggered - > > is this okay to have empty handler? > > Greg already said he won't accept that. And I'm quite sure these > interrupts > are level triggered, since that is the default on arch/omap. > > E.g. in arch/arm/mach-omap1/irq.c, a loop sets all irqs to level triggered > handling: set_irq_handler(j, handle_level_irq); (line 234) You should be looking at arch/arm/mach-davinci/irq.c and all interrupts except IRQ_TINT1_TINT34 is set to edge trigger mode (line 160). > > > In this specific case, these interrupt lines are internal to SOC and > hooked to ARM INTC from PRUSS. PRUSS has another INTC to handle system > events to PRUSS as well as to generate system events to host ARM. These > generated events are used for IPC between user application and PRU > firmware and for async notifications from PRU firmware to user space. I > don't see a reason to make it shared as we have 8 lines available for use. > As mentioned before ARM INTC interrupt processing logic converts > interrupts to active high pulses. > > What's a "pulse triggered interrupt"? I know level and edge triggered > ones. Basically it's same as edge triggered. Thanks, Pratheesh