Subject: Re: [PATCH 4/4] powerpc/mpic: add the mpic global timer support

From: Benjamin Herrenschmidt <[email-masked]>
Date: Fri, 06 May 2011 13:30:12 +1000

On Thu, 2011-05-05 at 20:07 -0500, Kumar Gala wrote:
> On Mar 24, 2011, at 4:43 PM, Scott Wood wrote:
> 
> > Add support for MPIC timers as requestable interrupt sources.
> > 
> > Based on http://patchwork.ozlabs.org/patch/20941/ by Dave Liu.
> > 
> > Signed-off-by: Dave Liu <[email-masked]>
> > Signed-off-by: Scott Wood <[email-masked]>
> > ---
> > arch/powerpc/include/asm/mpic.h |    3 +-
> > arch/powerpc/sysdev/mpic.c      |   92 ++++++++++++++++++++++++++++++++++++---
> > 2 files changed, 88 insertions(+), 7 deletions(-)
> 
> Ben,
> 
> Did you plan on review and pull this in or expect me to?

I might have been waiting for you I think ... :-) Or I wasn't sure. Feel
free to pick them up (if you do so, tag them as such in patchwork).

Cheers,
Ben.

> - k
> 
> 
> > 
> > diff --git a/arch/powerpc/include/asm/mpic.h b/arch/powerpc/include/asm/mpic.h
> > index 25a0cb3..664bee6 100644
> > --- a/arch/powerpc/include/asm/mpic.h
> > +++ b/arch/powerpc/include/asm/mpic.h
> > @@ -263,6 +263,7 @@ struct mpic
> > #ifdef CONFIG_SMP
> > 	struct irq_chip		hc_ipi;
> > #endif
> > +	struct irq_chip		hc_tm;
> > 	const char		*name;
> > 	/* Flags */
> > 	unsigned int		flags;
> > @@ -281,7 +282,7 @@ struct mpic
> > 
> > 	/* vector numbers used for internal sources (ipi/timers) */
> > 	unsigned int		ipi_vecs[4];
> > -	unsigned int		timer_vecs[4];
> > +	unsigned int		timer_vecs[8];
> > 
> > 	/* Spurious vector to program into unused sources */
> > 	unsigned int		spurious_vec;
> > diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
> > index 69f96ec..c173e67 100644
> > --- a/arch/powerpc/sysdev/mpic.c
> > +++ b/arch/powerpc/sysdev/mpic.c
> > @@ -219,6 +219,28 @@ static inline void _mpic_ipi_write(struct mpic *mpic, unsigned int ipi, u32 valu
> > 	_mpic_write(mpic->reg_type, &mpic->gregs, offset, value);
> > }
> > 
> > +static inline u32 _mpic_tm_read(struct mpic *mpic, unsigned int tm)
> > +{
> > +	unsigned int offset = MPIC_INFO(TIMER_VECTOR_PRI) +
> > +			      ((tm & 3) * MPIC_INFO(TIMER_STRIDE));
> > +
> > +	if (tm >= 4)
> > +		offset += 0x1000 / 4;
> > +
> > +	return _mpic_read(mpic->reg_type, &mpic->tmregs, offset);
> > +}
> > +
> > +static inline void _mpic_tm_write(struct mpic *mpic, unsigned int tm, u32 value)
> > +{
> > +	unsigned int offset = MPIC_INFO(TIMER_VECTOR_PRI) +
> > +			      ((tm & 3) * MPIC_INFO(TIMER_STRIDE));
> > +
> > +	if (tm >= 4)
> > +		offset += 0x1000 / 4;
> > +
> > +	_mpic_write(mpic->reg_type, &mpic->tmregs, offset, value);
> > +}
> > +
> > static inline u32 _mpic_cpu_read(struct mpic *mpic, unsigned int reg)
> > {
> > 	unsigned int cpu = mpic_processor_id(mpic);
> > @@ -269,6 +291,8 @@ static inline void _mpic_irq_write(struct mpic *mpic, unsigned int src_no,
> > #define mpic_write(b,r,v)	_mpic_write(mpic->reg_type,&(b),(r),(v))
> > #define mpic_ipi_read(i)	_mpic_ipi_read(mpic,(i))
> > #define mpic_ipi_write(i,v)	_mpic_ipi_write(mpic,(i),(v))
> > +#define mpic_tm_read(i)		_mpic_tm_read(mpic,(i))
> > +#define mpic_tm_write(i,v)	_mpic_tm_write(mpic,(i),(v))
> > #define mpic_cpu_read(i)	_mpic_cpu_read(mpic,(i))
> > #define mpic_cpu_write(i,v)	_mpic_cpu_write(mpic,(i),(v))
> > #define mpic_irq_read(s,r)	_mpic_irq_read(mpic,(s),(r))
> > @@ -628,6 +652,13 @@ static unsigned int mpic_is_ipi(struct mpic *mpic, unsigned int irq)
> > 	return (src >= mpic->ipi_vecs[0] && src <= mpic->ipi_vecs[3]);
> > }
> > 
> > +/* Determine if the linux irq is a timer */
> > +static unsigned int mpic_is_tm(struct mpic *mpic, unsigned int irq)
> > +{
> > +	unsigned int src = mpic_irq_to_hw(irq);
> > +
> > +	return (src >= mpic->timer_vecs[0] && src <= mpic->timer_vecs[7]);
> > +}
> > 
> > /* Convert a cpu mask from logical to physical cpu numbers. */
> > static inline u32 mpic_physmask(u32 cpumask)
> > @@ -814,6 +845,25 @@ static void mpic_end_ipi(struct irq_data *d)
> > 
> > #endif /* CONFIG_SMP */
> > 
> > +static void mpic_unmask_tm(struct irq_data *d)
> > +{
> > +	struct mpic *mpic = mpic_from_irq_data(d);
> > +	unsigned int src = mpic_irq_to_hw(d->irq) - mpic->timer_vecs[0];
> > +
> > +	DBG("%s: enable_tm: %d (tm %d)\n", mpic->name, irq, src);
> > +	mpic_tm_write(src, mpic_tm_read(src) & ~MPIC_VECPRI_MASK);
> > +	mpic_tm_read(src);
> > +}
> > +
> > +static void mpic_mask_tm(struct irq_data *d)
> > +{
> > +	struct mpic *mpic = mpic_from_irq_data(d);
> > +	unsigned int src = mpic_irq_to_hw(d->irq) - mpic->timer_vecs[0];
> > +
> > +	mpic_tm_write(src, mpic_tm_read(src) | MPIC_VECPRI_MASK);
> > +	mpic_tm_read(src);
> > +}
> > +
> > int mpic_set_affinity(struct irq_data *d, const struct cpumask *cpumask,
> > 		      bool force)
> > {
> > @@ -948,6 +998,12 @@ static struct irq_chip mpic_ipi_chip = {
> > };
> > #endif /* CONFIG_SMP */
> > 
> > +static struct irq_chip mpic_tm_chip = {
> > +	.irq_mask	= mpic_mask_tm,
> > +	.irq_unmask	= mpic_unmask_tm,
> > +	.irq_eoi	= mpic_end_irq,
> > +};
> > +
> > #ifdef CONFIG_MPIC_U3_HT_IRQS
> > static struct irq_chip mpic_irq_ht_chip = {
> > 	.irq_startup	= mpic_startup_ht_irq,
> > @@ -991,6 +1047,16 @@ static int mpic_host_map(struct irq_host *h, unsigned int virq,
> > 	}
> > #endif /* CONFIG_SMP */
> > 
> > +	if (hw >= mpic->timer_vecs[0] && hw <= mpic->timer_vecs[7]) {
> > +		WARN_ON(!(mpic->flags & MPIC_PRIMARY));
> > +
> > +		DBG("mpic: mapping as timer\n");
> > +		set_irq_chip_data(virq, mpic);
> > +		set_irq_chip_and_handler(virq, &mpic->hc_tm,
> > +					 handle_fasteoi_irq);
> > +		return 0;
> > +	}
> > +
> > 	if (hw >= mpic->irq_count)
> > 		return -EINVAL;
> > 
> > @@ -1147,6 +1213,9 @@ struct mpic * __init mpic_alloc(struct device_node *node,
> > 	mpic->hc_ipi.name = name;
> > #endif /* CONFIG_SMP */
> > 
> > +	mpic->hc_tm = mpic_tm_chip;
> > +	mpic->hc_tm.name = name;
> > +
> > 	mpic->flags = flags;
> > 	mpic->isu_size = isu_size;
> > 	mpic->irq_count = irq_count;
> > @@ -1157,10 +1226,14 @@ struct mpic * __init mpic_alloc(struct device_node *node,
> > 	else
> > 		intvec_top = 255;
> > 
> > -	mpic->timer_vecs[0] = intvec_top - 8;
> > -	mpic->timer_vecs[1] = intvec_top - 7;
> > -	mpic->timer_vecs[2] = intvec_top - 6;
> > -	mpic->timer_vecs[3] = intvec_top - 5;
> > +	mpic->timer_vecs[0] = intvec_top - 12;
> > +	mpic->timer_vecs[1] = intvec_top - 11;
> > +	mpic->timer_vecs[2] = intvec_top - 10;
> > +	mpic->timer_vecs[3] = intvec_top - 9;
> > +	mpic->timer_vecs[4] = intvec_top - 8;
> > +	mpic->timer_vecs[5] = intvec_top - 7;
> > +	mpic->timer_vecs[6] = intvec_top - 6;
> > +	mpic->timer_vecs[7] = intvec_top - 5;
> > 	mpic->ipi_vecs[0]   = intvec_top - 4;
> > 	mpic->ipi_vecs[1]   = intvec_top - 3;
> > 	mpic->ipi_vecs[2]   = intvec_top - 2;
> > @@ -1363,15 +1436,17 @@ void __init mpic_init(struct mpic *mpic)
> > 	/* Set current processor priority to max */
> > 	mpic_cpu_write(MPIC_INFO(CPU_CURRENT_TASK_PRI), 0xf);
> > 
> > -	/* Initialize timers: just disable them all */
> > +	/* Initialize timers to our reserved vectors and mask them for now */
> > 	for (i = 0; i < 4; i++) {
> > 		mpic_write(mpic->tmregs,
> > 			   i * MPIC_INFO(TIMER_STRIDE) +
> > -			   MPIC_INFO(TIMER_DESTINATION), 0);
> > +			   MPIC_INFO(TIMER_DESTINATION),
> > +			   1 << hard_smp_processor_id());
> > 		mpic_write(mpic->tmregs,
> > 			   i * MPIC_INFO(TIMER_STRIDE) +
> > 			   MPIC_INFO(TIMER_VECTOR_PRI),
> > 			   MPIC_VECPRI_MASK |
> > +			   (9 << MPIC_VECPRI_PRIORITY_SHIFT) |
> > 			   (mpic->timer_vecs[0] + i));
> > 	}
> > 
> > @@ -1480,6 +1555,11 @@ void mpic_irq_set_priority(unsigned int irq, unsigned int pri)
> > 			~MPIC_VECPRI_PRIORITY_MASK;
> > 		mpic_ipi_write(src - mpic->ipi_vecs[0],
> > 			       reg | (pri << MPIC_VECPRI_PRIORITY_SHIFT));
> > +	} else if (mpic_is_tm(mpic, irq)) {
> > +		reg = mpic_tm_read(src - mpic->timer_vecs[0]) &
> > +			~MPIC_VECPRI_PRIORITY_MASK;
> > +		mpic_tm_write(src - mpic->timer_vecs[0],
> > +			      reg | (pri << MPIC_VECPRI_PRIORITY_SHIFT));
> > 	} else {
> > 		reg = mpic_irq_read(src, MPIC_INFO(IRQ_VECTOR_PRI))
> > 			& ~MPIC_VECPRI_PRIORITY_MASK;
> > -- 
> > 1.7.1