Re: [Patch V1 3/6] genirq: Introduce msi_domain_{alloc|free}_irqs()

From: Marc Zyngier
Date: Thu Nov 13 2014 - 15:23:49 EST


On 13/11/14 11:43, Jiang Liu wrote:
> Introduce msi_domain_{alloc|free}_irqs() to alloc/free interrupts
> from generic MSI irqdomain.
>
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
> ---
> include/linux/msi.h | 35 ++++++++++++++++++++++++++++++
> kernel/irq/msi.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 94 insertions(+)
>
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 714716a3ffdd..6b356a1410b2 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -3,6 +3,7 @@
>
> #include <linux/kobject.h>
> #include <linux/list.h>
> +#include <asm/hw_irq.h> /* for msi_alloc_info_t */
>
> struct msi_msg {
> u32 address_lo; /* low 32 bits of msi message address */
> @@ -100,7 +101,26 @@ struct irq_chip;
> struct device_node;
> struct msi_domain_info;
>
> +#ifndef NUM_MSI_ALLOC_SCRATCHPAD_REGS
> +#define NUM_MSI_ALLOC_SCRATCHPAD_REGS 2
> +#endif
> +
> +/*
> + * Default structure for MSI interrupt allocation.
> + * Arch may overwrite it by define msi_alloc_info_t.
> + */
> +struct msi_alloc_info {
> + struct msi_desc *desc;
> + irq_hw_number_t hwirq;
> + long scratchpad[NUM_MSI_ALLOC_SCRATCHPAD_REGS];

As much as I'm relieved to see a generic structure here, could
scratchpad be slightly less awkward to use? Something like:

struct msi_alloc_info {
[...]
union {
unsigned long ul;
void *ptr;
} scratchpad[NUM_MSI_ALLOC_SCRATCHPAD_REGS];
};

That would avoid some very ugly casting.

Thanks,

M.
--
Jazz is not dead. It just smells funny...

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