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SubjectRe: [RFC PATCH 2/6] DRIVERS: IRQCHIP: CROSSBAR: Add support for Crossbar IP
Hi Thomas,

On Thursday 24 October 2013 02:50 PM, Thomas Gleixner wrote:
> On Mon, 30 Sep 2013, Sricharan R wrote:
>> +/*
>> + * @int_max: maximum number of supported interrupts
>> + * @irq_map: array of interrupts to crossbar number mapping
>> + * @crossbar_base: crossbar base address
>> + * @register_offsets: offsets for each irq number
>> + */
>> +struct crossbar_device {
>> + uint int_max;
>> + uint *irq_map;
> Why do you need another map here?
>
> Isn't the linear_revmap of the irqdomain sufficient?
linear_revmap gives the linux-irq for hw-irq,
but here i need the crossbar number corresponding to
the hwirq allocated. This is needed for setting up the
crossbar register in map.
>> +static inline const u32 allocate_free_irq(int cb_no)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < cb->int_max; i++) {
>> + if (cb->irq_map[i] == IRQ_FREE) {
>> + cb->irq_map[i] = cb_no;
>> + return i;
>> + }
>> + }
>> +
>> + return -ENODEV;
>> +}
>> +
>> +static int crossbar_domain_xlate(struct irq_domain *d,
>> + struct device_node *controller,
>> + const u32 *intspec, unsigned int intsize,
>> + unsigned long *out_hwirq,
>> + unsigned int *out_type)
>> +{
>> + return allocate_free_irq(intspec[1]) + GIC_IRQ_START;
> Mooo. In the error case you return:
>
> -ENODEV + GIC_IRQ_START == -19 + 32 == 13
>
> Yikes.
ya. will be a problem with error case. Will add a check here and
in the gic as well to check for the return value.
>> +
>> + /*
>> + * Register offsets are not linear because of the
>> + * reserved irqs. so find and store the offsets once.
>> + */
>> + for (i = 0; i < max; i++) {
>> + if (!cb->irq_map[i])
>> + continue;
>> +
>> + cb->register_offsets[i] = reserved;
>> + reserved += size;
> I'm amazed by such a brilliant hardware design.
>
> Thanks,
>
> tglx

Regards,
Sricharan


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