[08/13] irqchip: spear_shirq: Precalculate status mask

On Fri, Jun 20, 2014 at 3:04 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> Calculate the status mask at compile time, not at runtime.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  drivers/irqchip/spear-shirq.c |   13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
>
> Index: linux/drivers/irqchip/spear-shirq.c
> ===================================================================
> --- linux.orig/drivers/irqchip/spear-shirq.c
> +++ linux/drivers/irqchip/spear-shirq.c
> @@ -49,6 +49,7 @@ struct shirq_regs {
>   *
>   * base:       Base register address
>   * regs:       Register configuration for shared irq block
> + * mask:       Mask to apply to the status register
>   * virq_base:  Base virtual interrupt number
>   * nr_irqs:    Number of interrupts handled by this block
>   * offset:     Bit offset of the first interrupt
> @@ -57,6 +58,7 @@ struct shirq_regs {
>  struct spear_shirq {
>         void __iomem            *base;
>         struct shirq_regs       regs;
> +       u32                     mask;
>         u32                     virq_base;
>         u32                     nr_irqs;
>         u32                     offset;
> @@ -72,6 +74,7 @@ static DEFINE_SPINLOCK(lock);
>  static struct spear_shirq spear300_shirq_ras1 = {
>         .offset         = 0,
>         .nr_irqs        = 9,
> +       .mask           = ((0x1 << 9) - 1) << 0,
>         .regs = {
>                 .enb_reg = SPEAR300_INT_ENB_MASK_REG,
>                 .status_reg = SPEAR300_INT_STS_MASK_REG,
> @@ -89,6 +92,7 @@ static struct spear_shirq *spear300_shir
>  static struct spear_shirq spear310_shirq_ras1 = {
>         .offset         = 0,
>         .nr_irqs        = 8,
> +       .mask           = ((0x1 << 8) - 1) << 0,
>         .regs = {
>                 .enb_reg = -1,
>                 .status_reg = SPEAR310_INT_STS_MASK_REG,
> @@ -99,6 +103,7 @@ static struct spear_shirq spear310_shirq
>  static struct spear_shirq spear310_shirq_ras2 = {
>         .offset         = 8,
>         .nr_irqs        = 5,
> +       .mask           = ((0x1 << 5) - 1) << 8,
>         .regs = {
>                 .enb_reg = -1,
>                 .status_reg = SPEAR310_INT_STS_MASK_REG,
> @@ -109,6 +114,7 @@ static struct spear_shirq spear310_shirq
>  static struct spear_shirq spear310_shirq_ras3 = {
>         .offset         = 13,
>         .nr_irqs        = 1,
> +       .mask           = ((0x1 << 1) - 1) << 13,
>         .regs = {
>                 .enb_reg = -1,
>                 .status_reg = SPEAR310_INT_STS_MASK_REG,
> @@ -119,6 +125,7 @@ static struct spear_shirq spear310_shirq
>  static struct spear_shirq spear310_shirq_intrcomm_ras = {
>         .offset         = 14,
>         .nr_irqs        = 3,
> +       .mask           = ((0x1 << 3) - 1) << 14,
>         .regs = {
>                 .enb_reg = -1,
>                 .status_reg = SPEAR310_INT_STS_MASK_REG,
> @@ -141,6 +148,7 @@ static struct spear_shirq *spear310_shir
>  static struct spear_shirq spear320_shirq_ras3 = {
>         .offset         = 0,
>         .nr_irqs        = 7,
> +       .mask           = ((0x1 << 7) - 1) << 0,
>         .disabled       = 1,
>         .regs = {
>                 .enb_reg = SPEAR320_INT_ENB_MASK_REG,
> @@ -154,6 +162,7 @@ static struct spear_shirq spear320_shirq
>  static struct spear_shirq spear320_shirq_ras1 = {
>         .offset         = 7,
>         .nr_irqs        = 3,
> +       .mask           = ((0x1 << 3) - 1) << 7,
>         .regs = {
>                 .enb_reg = -1,
>                 .status_reg = SPEAR320_INT_STS_MASK_REG,
> @@ -165,6 +174,7 @@ static struct spear_shirq spear320_shirq
>  static struct spear_shirq spear320_shirq_ras2 = {
>         .offset         = 10,
>         .nr_irqs        = 1,
> +       .mask           = ((0x1 << 1) - 1) << 10,
>         .regs = {
>                 .enb_reg = -1,
>                 .status_reg = SPEAR320_INT_STS_MASK_REG,
> @@ -176,6 +186,7 @@ static struct spear_shirq spear320_shirq
>  static struct spear_shirq spear320_shirq_intrcomm_ras = {
>         .offset         = 11,
>         .nr_irqs        = 11,
> +       .mask           = ((0x1 << 11) - 1) << 11,
>         .regs = {
>                 .enb_reg = -1,
>                 .status_reg = SPEAR320_INT_STS_MASK_REG,

If you like, maybe this instead of above diff:

                spear_shirq_register(shirq_blocks[i]);


> @@ -239,7 +250,7 @@ static void shirq_handler(unsigned irq,
>
>         chip->irq_ack(idata);
>
> -       mask = ((0x1 << shirq->nr_irqs) - 1) << shirq->offset;
> +       mask = shirq->mask;
>         while ((val = readl(shirq->base + shirq->regs.status_reg) &
>                                 mask)) {
>
>
>
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On Fri, 20 Jun 2014, Viresh Kumar wrote:
> On Fri, Jun 20, 2014 at 3:04 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> > @@ -176,6 +186,7 @@ static struct spear_shirq spear320_shirq
> >  static struct spear_shirq spear320_shirq_intrcomm_ras = {
> >         .offset         = 11,
> >         .nr_irqs        = 11,
> > +       .mask           = ((0x1 << 11) - 1) << 11,
> >         .regs = {
> >                 .enb_reg = -1,
> >                 .status_reg = SPEAR320_INT_STS_MASK_REG,
> 
> If you like, maybe this instead of above diff:

What's wrong with letting the compiler fill it in?
 
> diff --git a/drivers/irqchip/spear-shirq.c b/drivers/irqchip/spear-shirq.c
> index 3fdda3a..40c5c1b 100644
> --- a/drivers/irqchip/spear-shirq.c
> +++ b/drivers/irqchip/spear-shirq.c
> @@ -281,6 +281,8 @@ static int __init shirq_init(struct spear_shirq
> **shirq_blocks, int block_nr,
>                 shirq_blocks[i]->base = base;
>                 shirq_blocks[i]->irq_base = irq_find_mapping(shirq_domain,
>                                 hwirq);
> +               shirq_blocks[i]->mask = ((0x1 << shirq_blocks[i]->nr_irqs) - 1)
> +                                       << shirq_blocks[i]->offset;
>                 shirq_blocks[i]->irq = irq_of_parse_and_map(np, i);
> 
>                 spear_shirq_register(shirq_blocks[i]);
> 
> 
> > @@ -239,7 +250,7 @@ static void shirq_handler(unsigned irq,
> >
> >         chip->irq_ack(idata);
> >
> > -       mask = ((0x1 << shirq->nr_irqs) - 1) << shirq->offset;
> > +       mask = shirq->mask;
> >         while ((val = readl(shirq->base + shirq->regs.status_reg) &
> >                                 mask)) {
> >
> >
> >
> 
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On 20 June 2014 13:36, Thomas Gleixner <tglx@linutronix.de> wrote:
> On Fri, 20 Jun 2014, Viresh Kumar wrote:
>> On Fri, Jun 20, 2014 at 3:04 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
>> > @@ -176,6 +186,7 @@ static struct spear_shirq spear320_shirq
>> >  static struct spear_shirq spear320_shirq_intrcomm_ras = {
>> >         .offset         = 11,
>> >         .nr_irqs        = 11,
>> > +       .mask           = ((0x1 << 11) - 1) << 11,
>> >         .regs = {
>> >                 .enb_reg = -1,
>> >                 .status_reg = SPEAR320_INT_STS_MASK_REG,
>>
>> If you like, maybe this instead of above diff:
>
> What's wrong with letting the compiler fill it in?

>> +               shirq_blocks[i]->mask = ((0x1 << shirq_blocks[i]->nr_irqs) - 1)
>> +                                       << shirq_blocks[i]->offset;

Just for better readability as it doesn't have magic numbers in it
and the performance impact wouldn't be much as its done just
once on boot.
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