On Thu, Jan 12, 2012 at 5:37 PM, Rob Herring <robherri...@gmail.com> wrote:
> On 01/11/2012 02:22 PM, Grant Likely wrote:
>> Add support for a legacy mapping where irq = (hwirq - first_hwirq +
>> first_irq)
>> so that a controller driver can allocate a fixed range of irq_descs and use
>> a simple calculation to translate back and forth between linux and hw irq
>> numbers. This is needed to use an irq_domain with many of the ARM interrupt
>> controller drivers that manage their own irq_desc allocations. Ultimately
>> the goal is to migrate those drivers to use the linear revmap, but doing it
>> this way allows each driver to be converted separately which makes the
>> migration path easier.
>>
>> This patch generalizes the IRQ_DOMAIN_MAP_LEGACY method to use
>> (first_irq-first_hwirq) as the offset between hwirq and linux irq number,
>> and adds checks to make sure that the hwirq number does not exceed range
>> assigned to the controller.
>>
>> Signed-off-by: Grant Likely <grant.lik...@secretlab.ca>
>> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
>> ---
>> arch/powerpc/include/asm/irq.h | 3 -
>> arch/powerpc/sysdev/i8259.c | 2 +-
>> arch/powerpc/sysdev/tsi108_pci.c | 2 +-
>> include/linux/irqdomain.h | 20 +++++++++-
>> kernel/irq/irqdomain.c | 78
>> +++++++++++++++++++++++++-------------
>> 5 files changed, 73 insertions(+), 32 deletions(-)
>>
>
> snip...
>
>> @@ -454,8 +477,11 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
>> return 0;
>>
>> /* legacy -> bail early */
>> - if (domain->revmap_type == IRQ_DOMAIN_MAP_LEGACY)
>> - return hwirq;
>> + if (domain->revmap_type == IRQ_DOMAIN_MAP_LEGACY) {
>> + if (hwirq > domain->revmap_data.legacy.size)
>> + return 0;
>> + return domain->revmap_data.legacy.first_irq + hwirq;
>
> This needs a "- domain->revmap_data.legacy.first_hwirq"
Good catch, thanks.
g.
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