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 10:20:20 +0000 [thread overview]
Message-ID: <e4d30ff2485c3f9ffd2b934f1f757d19@www.loen.fr> (raw)
In-Reply-To: <d7416bdb-e20a-42e1-daff-c61369f359fa@suse.de>
On 2019-11-19 23:33, Andreas Färber wrote:
> Am 19.11.19 um 23:29 schrieb Marc Zyngier:
>> On Tue, 19 Nov 2019 21:56:48 +0100
>> Andreas Färber <afaerber@suse.de> wrote:
>>> Am 19.11.19 um 13:01 schrieb Marc Zyngier:
>>>> On 2019-11-19 02:19, Andreas Färber wrote:
>>>>> +static void rtd1195_mux_enable_irq(struct irq_data *data)
>>>>> +{
>>>>> + struct rtd1195_irq_mux_data *mux_data =
>>>>> irq_data_get_irq_chip_data(data);
>>>>> + unsigned long flags;
>>>>> + u32 mask;
>>>>> +
>>>>> + mask = mux_data->info->isr_to_int_en_mask[data->hwirq];
>>>>> + if (!mask)
>>>>> + return;
>>>>
>>>> How can this happen? You've mapped the interrupt, so it exists.
>>>> I can't see how you can decide to fail such enable.
>>>
>>> The [UMSK_]ISR bits and the SCPU_INT_EN bits are not (all) the
>>> same.
>>>
>>> My ..._isr_to_scpu_int_en[] arrays have 32 entries for O(1) lookup,
>>> but
>>> are sparsely populated. So there are circumstances such as WDOG_NMI
>>> as
>>> well as reserved bits that we cannot enable.
>>
>> But the you should have failed the map. The moment you allow the
>> mapping to occur, you have accepted the contract that this interrupt
>> is
>> usable.
>>
>>> This check should be
>>> identical to v3; the equivalent mask check inside the interrupt
>>> handler
>>> was extended with "mask &&" to do the same in this v4.
>>
>> Spurious interrupts are a different matter. What I'm objecting to
>> here
>> is a simple question of logic, whether or not you are allowed to
>> fail
>> enabling an interrupt that you've otherwise allowed to be populated.
>
> Then what are you suggesting instead? I don't see how my array map
> lookup could fail other than returning a zero value, given its static
> initialization. Check for a zero mask in
> rtd1195_mux_irq_domain_map()?
> Then we wouldn't be able to use the mentioned WDOG_NMI. Add another
> per-mux info field for which interrupts are valid to map?
I'm suggesting that you fail the map if you're unable to allow the
interrupt to be enabled.
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2019-11-20 10:20 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 [this message]
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
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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