[PATCH v2 4/7] ARM: pxa: add devicetree code for irq handling

[Haojian Zhuang]

On Sat, Jul 28, 2012 at 5:56 PM, Daniel Mack <zonque at gmail.com> wrote:
> Hi Haojian,
>
> On 28.07.2012 09:17, Haojian Zhuang wrote:
>> On Fri, Jul 27, 2012 at 3:16 AM, Daniel Mack <zonque at gmail.com> wrote:
>>> Properly register on-chip interrupt using the irqdomain logic. The
>>> number of interrupts is taken from the devicetree node.
>>>
>>> Signed-off-by: Daniel Mack <zonque at gmail.com>
>>> ---
>>>  arch/arm/mach-pxa/irq.c    | 73 ++++++++++++++++++++++++++++++++++++++++++++++
>>>  arch/arm/mach-pxa/pxa3xx.c | 17 +++++++++--
>>>  2 files changed, 88 insertions(+), 2 deletions(-)
>>>
>>> +#ifdef CONFIG_OF
>>> +static struct irq_domain *pxa_irq_domain;
>>> +
>>> +static int pxa_irq_map(struct irq_domain *h, unsigned int virq,
>>> +                      irq_hw_number_t hw)
>>> +{
>>> +       int irq, i = hw % 32;
>>> +       void __iomem *base = irq_base(hw / 32);
>>> +
>>> +       /* initialize interrupt priority */
>>> +       if (cpu_has_ipr())
>>> +               __raw_writel(i | IPR_VALID, IRQ_BASE + IPR(i));
>> Since we have DT support at here. Could we use property for interrupt priority?
>
> Not sure what you mean here. Can you elaborate? I couldn't find any
> reference to IRQ priorities in other platforms either.
>
> Maybe we can also add that in a separate patch, which would also help in
> tracking possible regressions du to such a change?
>
cpu_has_ipr() returns true if CPU isn't PXA25x.
My point is that we can avoid to use cpu_is_xxx() while DT is used. We only need
to append a property "marvell,intc-priority" is DTS. So the code could
be changed
in below.
if (of_find_property(np, "marvell,intc-priority", NULL))
           __raw_writel(i | IPR_VALID, IRQ_BASE + IPR(i));

>>> +       irq = PXA_IRQ(virq);
>> #ifdef CONFIG_PXA_HAVE_ISA_IRQS
>> #define PXA_ISA_IRQ(x)  (x)
>> #define PXA_ISA_IRQ_NUM (16)
>> #else
>> #define PXA_ISA_IRQ_NUM (0)
>> #endif
>>
>> Could we avoid to use PXA_IRQ() at here? We can make use of
>> NR_IRQS_LEGACY that is 16. Since you already use irq_alloc_descs()
>> to allocate irqs that virtual irq number starts from 16. So you needn't
>> use PXA_IRQ() any more.
>
> Ok, I changed this. Note that there's still need to subtract
> NR_IRQS_LEGACY from the virq that is passed in to the .map function,
> because early_irq_init() in kernel/irq/irqdesc.c will pre-allocate the
> IRQs the platform claims to have natively, which defaults to 16 on PXA,
> unless the machine descriptor sets nr_irqs, which it doesn't in case of DT.
>
You needn't subtract NR_IRQS_LEGACY. PXA25x hwirq starts from
16 & PXA27x/PXA3xx hwirq starts from 0. While DT is used, irq_alloc_descs()
allocates virq from NR_IRQS_LEGACY. For PXA25x, there's exactly match.
For PXA27x/PXA3xx, there's a little different. But it doesn't matter. We needn't
force virq starting from 0 on PXA27x/PXA3xx. The first virq starts from 16 is
also OK.

Although I use this subtract in arch-mmp, it's a little different in
arch-pxa because
of PXA25x.

> I also found another hunk that I forgot to squash in the v2 series. I
> will repost the whole thing and also include the two GPIO patches that
> should go through your tree.
>
>
> Thanks for the review,
>
> Daniel
>