[PATCH] Fix masking of interrupts for 52xx GPT IRQ.

[Henk Stegeman]

What if the unmask/mask functions are dropped and only interrupt
enable/disable functions are provided?
I.e: rename the old unmask/mask functions to enable/disable and
register them as enable/disable? I did try that, and it works too, no
spurious IRQ's and no missing IRQ's.


Cheers,

Henk.

On Wed, Mar 2, 2011 at 10:30 PM, Grant Likely <grant.likely at secretlab.ca> wrote:
> [fixed top-posted reply]
>
> On Wed, Feb 9, 2011 at 3:16 AM, Henk Stegeman <henk.stegeman at gmail.com> wrote:
>> On Mon, Feb 7, 2011 at 12:05 AM, Benjamin Herrenschmidt
>> <benh at kernel.crashing.org> wrote:
>>> On Sat, 2011-01-15 at 02:28 +0100, Henk Stegeman wrote:
>>>> When using the GPT as interrupt controller interupts were missing.
>>>> It turned out the IrqEn bit of the GPT is not a mask bit, but it also
>>>> disables interrupt generation. This modification masks interrupt one
>>>> level down the cascade. Note that masking one level down the cascade
>>>> is only valid here because the GPT as interrupt ontroller only serves
>>>> one IRQ.
>>>
>>> I'm not too sure here... You shouldn't implemen t both mask/unmask and
>>> enable/disable on the same irq_chip and certainly not cal
>>> enable_irq/disable_irq from a mask or an unmask callback...
>>>
>>> Now, I'm not familiar with the HW here, can you tell me more about what
>>> exactly is happening, how things are layed out and what you are trying
>>> to fix ?
>>>
> [...]
>> Because the old code in the unmask/mask function did enable/disable
>> and I didn't want to just drop that code, I provided it via the
>> enable/disable function.
>> What is wrong by implementing & registering both mask/unmask and
>> enable/disable for the same irq_chip?
>> If it is wrong it would be nice to let the kernel print a big fat
>> warning when this is registered.
>
> After some digging, yes Ben is right.  It doesn't make much sense to
> provide an enable/disable function along with the mask/unmask.  I
> think you can safely drop the old enable/disable code.  I'm going to
> drop this patch from my tree and you can respin and retest.
>
> g.
>
>>
>> Cheers,
>>
>> Henk
>>
>
>>>
>>>> Signed-off-by: Henk Stegeman <henk.stegeman at gmail.com>
>>>> ---
>>>>  arch/powerpc/platforms/52xx/mpc52xx_gpt.c |   25 ++++++++++++++++++++++---
>>>>  1 files changed, 22 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
>>>> index 6f8ebe1..9ae2045 100644
>>>> --- a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
>>>> +++ b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
>>>> @@ -91,7 +91,7 @@ struct mpc52xx_gpt_priv {
>>>>       struct irq_host *irqhost;
>>>>       u32 ipb_freq;
>>>>       u8 wdt_mode;
>>>> -
>>>> +     int cascade_virq;
>>>>  #if defined(CONFIG_GPIOLIB)
>>>>       struct of_gpio_chip of_gc;
>>>>  #endif
>>>> @@ -136,18 +136,35 @@ DEFINE_MUTEX(mpc52xx_gpt_list_mutex);
>>>>  static void mpc52xx_gpt_irq_unmask(unsigned int virq)
>>>>  {
>>>>       struct mpc52xx_gpt_priv *gpt = get_irq_chip_data(virq);
>>>> +
>>>> +     enable_irq(gpt->cascade_virq);
>>>> +
>>>> +}
>>>> +
>>>> +static void mpc52xx_gpt_irq_mask(unsigned int virq)
>>>> +{
>>>> +     struct mpc52xx_gpt_priv *gpt = get_irq_chip_data(virq);
>>>> +
>>>> +     disable_irq(gpt->cascade_virq);
>>>> +}
>>>> +
>>>> +static void mpc52xx_gpt_irq_enable(unsigned int virq)
>>>> +{
>>>> +     struct mpc52xx_gpt_priv *gpt = get_irq_chip_data(virq);
>>>>       unsigned long flags;
>>>>
>>>> +     dev_dbg(gpt->dev, "%s %d\n", __func__, virq);
>>>>       spin_lock_irqsave(&gpt->lock, flags);
>>>>       setbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN);
>>>>       spin_unlock_irqrestore(&gpt->lock, flags);
>>>>  }
>>>>
>>>> -static void mpc52xx_gpt_irq_mask(unsigned int virq)
>>>> +static void mpc52xx_gpt_irq_disable(unsigned int virq)
>>>>  {
>>>>       struct mpc52xx_gpt_priv *gpt = get_irq_chip_data(virq);
>>>>       unsigned long flags;
>>>>
>>>> +     dev_dbg(gpt->dev, "%s %d\n", __func__, virq);
>>>>       spin_lock_irqsave(&gpt->lock, flags);
>>>>       clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN);
>>>>       spin_unlock_irqrestore(&gpt->lock, flags);
>>>> @@ -184,6 +201,8 @@ static struct irq_chip mpc52xx_gpt_irq_chip = {
>>>>       .name = "MPC52xx GPT",
>>>>       .unmask = mpc52xx_gpt_irq_unmask,
>>>>       .mask = mpc52xx_gpt_irq_mask,
>>>> +     .enable = mpc52xx_gpt_irq_enable,
>>>> +     .disable = mpc52xx_gpt_irq_disable,
>>>>       .ack = mpc52xx_gpt_irq_ack,
>>>>       .set_type = mpc52xx_gpt_irq_set_type,
>>>>  };
>>>> @@ -268,7 +287,7 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
>>>>       if ((mode & MPC52xx_GPT_MODE_MS_MASK) == 0)
>>>>               out_be32(&gpt->regs->mode, mode | MPC52xx_GPT_MODE_MS_IC);
>>>>       spin_unlock_irqrestore(&gpt->lock, flags);
>>>> -
>>>> +     gpt->cascade_virq = cascade_virq;
>>>>       dev_dbg(gpt->dev, "%s() complete. virq=%i\n", __func__, cascade_virq);
>>>>  }
>>>>
>>>
>>>
>>>
>>
>
>
>
> --
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.
>