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Date: Wed, 30 Jan 2019 15:11:26 +0100
From: Lucas Stach <l.stach@...gutronix.de>
To: Dong Aisheng <dongas86@...il.com>
Cc: Aisheng Dong <aisheng.dong@....com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"shawnguo@...nel.org" <shawnguo@...nel.org>,
dl-linux-imx <linux-imx@....com>,
"robh+dt@...nel.org" <robh+dt@...nel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"tglx@...utronix.de" <tglx@...utronix.de>,
Marc Zyngier <marc.zyngier@....com>
Subject: Re: [PATCH V2 4/4] irq: imx: irqsteer: add multi output interrupts
support
Am Mittwoch, den 30.01.2019, 22:03 +0800 schrieb Dong Aisheng:
> > On Wed, Jan 30, 2019 at 9:33 PM Lucas Stach <l.stach@...gutronix.de> wrote:
> >
> > Am Mittwoch, den 30.01.2019, 13:06 +0000 schrieb Aisheng Dong:
> > > One irqsteer channel can support up to 8 output interrupts.
> > >
> > > > > > > > Cc: Marc Zyngier <marc.zyngier@....com>
> > > > > > > > Cc: Lucas Stach <l.stach@...gutronix.de>
> > > > > > > > Cc: Shawn Guo <shawnguo@...nel.org>
> > > > Signed-off-by: Dong Aisheng <aisheng.dong@....com>
> > >
> > > ---
> > > ChangeLog:
> > > v1->v2:
> > > * calculate irq_count by fsl,num-irqs instead of parsing interrupts
> > > property from devicetree to match the input interrupts and outputs
> > > * improve output interrupt handler by searching only two registers
> > > withint the same group
> > > ---
> > > drivers/irqchip/irq-imx-irqsteer.c | 76 +++++++++++++++++++++++++++++---------
> > > 1 file changed, 59 insertions(+), 17 deletions(-)
> > >
> > > diff --git a/drivers/irqchip/irq-imx-irqsteer.c b/drivers/irqchip/irq-imx-irqsteer.c
> > > index 67ed862..cc40039 100644
> > > --- a/drivers/irqchip/irq-imx-irqsteer.c
> > > +++ b/drivers/irqchip/irq-imx-irqsteer.c
> > > @@ -10,6 +10,7 @@
> > > #include <linux/irqchip/chained_irq.h>
> > > #include <linux/irqdomain.h>
> > > #include <linux/kernel.h>
> > > +#include <linux/of_irq.h>
> > > #include <linux/of_platform.h>
> > > #include <linux/spinlock.h>
> > >
> > > @@ -21,10 +22,13 @@
> > > > #define CHAN_MINTDIS(t) (CTRL_STRIDE_OFF(t, 3) + 0x4)
> > > > #define CHAN_MASTRSTAT(t) (CTRL_STRIDE_OFF(t, 3) + 0x8)
> > > > +#define CHAN_MAX_OUTPUT_INT 0x8
> > >
> > > +
> > > struct irqsteer_data {
> > > > > void __iomem *regs;
> > > > > struct clk *ipg_clk;
> > > > > - int irq;
> > > > > + int irq[CHAN_MAX_OUTPUT_INT];
> > > > > + int irq_count;
> > > > > raw_spinlock_t lock;
> > > > > int reg_num;
> > > > > int channel;
> > >
> > > @@ -87,26 +91,45 @@ static const struct irq_domain_ops imx_irqsteer_domain_ops = {
> > > > > .xlate = irq_domain_xlate_onecell,
> > >
> > > };
> > >
> > > +static int imx_irqsteer_get_hwirq_base(struct irqsteer_data *data, u32 irq)
> > > +{
> > > > + int i;
> > >
> > > +
> > > > + for (i = 0; i < data->irq_count; i++) {
> > > > + if (data->irq[i] == irq)
> > >
> > > + break;
> >
> > return i * 64; here...
> > > + }
> > > +
> > > + return i * 64;
> >
> > ... and -EINVAL or something here, so we don't return a out of bounds
> > hwirq base if the loop ever doesn't match something?
> >
>
> Good suggestion, will add it.
>
> > > +}
> > > +
> > > static void imx_irqsteer_irq_handler(struct irq_desc *desc)
> > > {
> > > > struct irqsteer_data *data = irq_desc_get_handler_data(desc);
> > > > + int hwirq;
> > > > int i;
> > > > chained_irq_enter(irq_desc_get_chip(desc), desc);
> > > > - for (i = 0; i < data->reg_num * 32; i += 32) {
> > > > - int idx = imx_irqsteer_get_reg_index(data, i);
> > > > + hwirq = imx_irqsteer_get_hwirq_base(data, irq_desc_get_irq(desc));
> > >
> > > +
> > > > + for (i = 0; i < 2; i++) {
> > > > + int idx = imx_irqsteer_get_reg_index(data, hwirq);
> > > > unsigned long irqmap;
> > > > int pos, virq;
> > > > + if (hwirq >= data->reg_num * 32)
> > > > + break;
> > >
> > > +
> > > > irqmap = readl_relaxed(data->regs +
> > > > CHANSTATUS(idx, data->reg_num));
> > > > for_each_set_bit(pos, &irqmap, 32) {
> > > > - virq = irq_find_mapping(data->domain, pos + i);
> > >
> > > + virq = irq_find_mapping(data->domain, pos + hwirq);
> >
> > The irq index calculation need to be "pos + i * 32 + hwirq", otherwise
> > this will map to the wrong virqs for the second register in each group.
> >
>
> For second register map, hwirq will plus 32 in next round.
> So i can't see this will map a wrong virqs.
> And it looks to me ""pos + i * 32 + hwirq" is equal to "hwirq + 32".
> Am i missed something?
You are right, I forgot about the hwirq being incremented in the loop
when writing this comment.
> > > if (virq)
> > > > generic_handle_irq(virq);
> > > > }
> > >
> > > + hwirq += 32;
> >
> > Could be folded into the loop head.
> >
>
> You mean “for (i = 0; i < 2; i++, hwirq +=32)” ?
> I feel that's not quite necessary.
I personally find that quite a bit clearer than incrementing the loop
variables at different spots. And I probably wouldn't have missed hwirq
being incremented in the loop if I had seen it in the head.
Regards,
Lucas
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