Le 14/01/2015 15:03, Boris Brezillon a écrit :
> On Wed, 14 Jan 2015 14:36:42 +0100
> Nicolas Ferre <nicolas.ferre@xxxxxxxxx> wrote:
>
>> Le 13/01/2015 19:46, Boris Brezillon a écrit :
>>> Some interrupt controllers are multiplexing several peripheral IRQs on
>>> a single interrupt line.
>>> While this is not a problem for most IRQs (as long as all peripherals
>>> request the interrupt with IRQF_SHARED flag set), multiplexing timers and
>>> other type of peripherals will generate a WARNING (mixing IRQF_NO_SUSPEND
>>> and !IRQF_NO_SUSPEND is prohibited).
>>>
>>> Create a dumb irq demultiplexer which simply forwards interrupts to all
>>> peripherals (exactly what's happening with IRQ_SHARED) but keep a unique
>>> irq number for each peripheral, thus preventing the IRQF_NO_SUSPEND
>>> and !IRQF_NO_SUSPEND mix on a given interrupt.
>>>
>>> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
>>> ---
>>> drivers/irqchip/Kconfig | 4 ++
>>> drivers/irqchip/Makefile | 1 +
>>> drivers/irqchip/irq-dumb-demux.c | 70 ++++++++++++++++++++
>>> include/linux/irq.h | 49 ++++++++++++++
>>> include/linux/irqdomain.h | 1 +
>>> kernel/irq/Kconfig | 5 ++
>>> kernel/irq/Makefile | 1 +
>>> kernel/irq/chip.c | 41 ++++++++++++
>>> kernel/irq/dumb-demux-chip.c | 140 +++++++++++++++++++++++++++++++++++++++
>>> kernel/irq/handle.c | 31 ++++++++-
>>> kernel/irq/internals.h | 3 +
>>> 11 files changed, 344 insertions(+), 2 deletions(-)
>>> create mode 100644 drivers/irqchip/irq-dumb-demux.c
>>> create mode 100644 kernel/irq/dumb-demux-chip.c
[..]
>>> +static void irq_dumb_demux_mask(struct irq_data *d)
>>> +{
>>> + struct irq_chip_dumb_demux *demux = irq_data_get_irq_chip_data(d);
>>> +
>>> + clear_bit(d->hwirq, &demux->unmasked);
>>> +
>>> + if (!demux->unmasked)
>>> + disable_irq_nosync(demux->src_irq);
>>> +}
>>> +
>>> +static void irq_dumb_demux_unmask(struct irq_data *d)
>>> +{
>>> + struct irq_chip_dumb_demux *demux = irq_data_get_irq_chip_data(d);
>>> + bool enable_src_irq = !demux->unmasked;
>>
>> Why this additional "bool" unlike the other function above?
>
> Because set_bit will modify the unmasked status and we must check if it
> is equal to 0 (in other terms, all irqs are masked) before modifying it
> in order to know whether we should enable the src irq or not.
pfffff! ok, sorry for the noise then ;-)
>>> +
>>> + set_bit(d->hwirq, &demux->unmasked);
>>> +
>>> + if (enable_src_irq)
>>> + enable_irq(demux->src_irq);
>>> +}
>>> +
[...]
Bye,
--
Nicolas Ferre
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