From: Marc Zyngier <maz@kernel.org> To: "Andreas Färber" <afaerber@suse.de> Cc: <linux-realtek-soc@lists.infradead.org>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, Aleix Roca Nonell <kernelrocks@gmail.com>, James Tai <james.tai@realtek.com>, Thomas Gleixner <tglx@linutronix.de>, Jason Cooper <jason@lakedaemon.net> Subject: Re: [PATCH v4 2/8] irqchip: Add Realtek RTD1295 mux driver Date: Wed, 20 Nov 2019 10:18:57 +0000 [thread overview] Message-ID: <8137861d0a89dd246b3334ac596da8be@www.loen.fr> (raw) In-Reply-To: <0bff78c1-a1d0-9631-fbf4-e0d1ef1264ea@suse.de> On 2019-11-19 23:25, Andreas Färber wrote: > Am 19.11.19 um 13:01 schrieb Marc Zyngier: >> On 2019-11-19 02:19, Andreas Färber wrote: >>> diff --git a/drivers/irqchip/irq-rtd1195-mux.c >>> b/drivers/irqchip/irq-rtd1195-mux.c >>> new file mode 100644 >>> index 000000000000..e6b08438b23c >>> --- /dev/null >>> +++ b/drivers/irqchip/irq-rtd1195-mux.c > [...] >>> +static void rtd1195_mux_irq_handle(struct irq_desc *desc) >>> +{ >>> + struct rtd1195_irq_mux_data *data = >>> irq_desc_get_handler_data(desc); >>> + struct irq_chip *chip = irq_desc_get_chip(desc); >>> + u32 isr, mask; >>> + int i; >>> + >>> + chained_irq_enter(chip, desc); >>> + >>> + isr = readl_relaxed(data->reg_isr); >>> + >>> + while (isr) { >>> + i = __ffs(isr); >>> + isr &= ~BIT(i); >>> + >>> + mask = data->info->isr_to_int_en_mask[i]; >>> + if (mask && !(data->scpu_int_en & mask)) >>> + continue; >>> + >>> + if (!generic_handle_irq(irq_find_mapping(data->domain, >>> i))) >>> + writel_relaxed(BIT(i), data->reg_isr); >> >> What does this write do exactly? It is the same thing as a 'mask', >> which is pretty odd. So either: >> >> - this is not doing anything and your 'mask' callback is bogus >> (otherwise you'd never have more than a single interrupt) >> >> - or this is an ACK operation, and this should be described as >> such (and then fix the mask/unmask/enable/disable mess that >> results from it). > > This is supposed to be an ACK, i.e. clear-1-bits operation. If it is an ACK, model it as such, and do not open-code it. > > The BSP had extended various drivers, such as 8250 UART, to do this > ack > in their interrupt handler through an additional DT reg region. I > tried > to clean that up by handling it centrally here in the irqchip driver. > >> >> as I can't see how the same register can be used for both purposes. >> You should be able to verify this experimentally, even without >> documentation. > > There are three registers here: > > MIS_UMSK_ISR - MISC unmasked interrupt status register > MIS_ISR - MISC masked interrupt status register > MIS_SCPU_INT_EN - MISC SCPU interrupt enable register > > The latter is a regular R/W register; the former two have a > write_data > field as BIT(0), with 1 indicating a write vs. 0 indicating clear, > RAZ. > > By enabling/disabling in _SCPU_INT_EN we mask/unmask them in _ISR but > not in _UMSK_ISR. > > Does that shed any more light? None whatsoever. Your mask callback doesn't make any sense, since it actually acks the interrupt. My gut feeling is that your enable/disable should really be mask/unmask. > > So given that we're iterating over reg_isr above, we could probably > drop > the mask check here... > > In addition there are MIS_[UMSK_]ISR_SWC and MIS_SETTING_SWC > registers > for Secure World, and MIS_FAST_INT_EN_* and MIS_FAST_ISR as well as > various GPIO interrupt registers. This doesn't seem relevant to the discussion here. M. -- Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2019-11-20 10:19 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-19 2:19 [PATCH v4 0/8] ARM: Realtek RTD1195/RTD1295/RTD1395 IRQ mux Andreas Färber 2019-11-19 2:19 ` [PATCH v4 1/8] dt-bindings: interrupt-controller: Add Realtek RTD1195/RTD1295 mux Andreas Färber 2019-11-19 2:19 ` [PATCH v4 2/8] irqchip: Add Realtek RTD1295 mux driver Andreas Färber 2019-11-19 12:01 ` Marc Zyngier 2019-11-19 20:56 ` Andreas Färber 2019-11-19 22:29 ` Marc Zyngier 2019-11-19 23:33 ` Andreas Färber 2019-11-20 10:20 ` Marc Zyngier 2019-11-20 13:34 ` Andreas Färber 2019-11-20 14:32 ` Marc Zyngier 2019-11-19 23:25 ` Andreas Färber 2019-11-20 10:18 ` Marc Zyngier [this message] 2019-11-20 12:12 ` Andreas Färber 2019-11-20 12:23 ` Marc Zyngier 2019-11-19 2:19 ` [PATCH v4 3/8] arm64: dts: realtek: rtd129x: Add irq muxes and UART interrupts Andreas Färber 2019-11-19 2:19 ` [PATCH v4 4/8] irqchip: rtd1195-mux: Add RTD1195 definitions Andreas Färber 2019-11-19 2:19 ` [PATCH v4 5/8] ARM: dts: rtd1195: Add irq muxes and UART interrupts Andreas Färber 2019-11-19 2:19 ` [PATCH v4 6/8] dt-bindings: interrupt-controller: rtd1195-mux: Add RTD1395 Andreas Färber 2019-11-19 2:19 ` [PATCH v4 7/8] irqchip: rtd1195-mux: Add RTD1395 definitions Andreas Färber 2019-11-19 2:19 ` [PATCH v4 8/8] arm64: dts: realtek: rtd139x: Add irq muxes and UART interrupts Andreas Färber
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