[PATCH] irqchip: gic: Fix core ID calculation when topology is read from DT

[Jason Cooper]

On Thu, Jul 17, 2014 at 05:23:44PM +0200, Tomasz Figa wrote:
> Certain GIC implementation, namely those found on earlier, single
> cluster, Exynos SoCs, have registers mapped without per-CPU banking,
> which means that the driver needs to use different offset for each CPU.
> 
> Currently the driver calculates the offset by multiplying value returned
> by cpu_logical_map() by CPU offset parsed from DT. This is correct when
> CPU topology is not specified in DT and aforementioned function returns
> core ID alone. However when DT contains CPU topology, the function
> changes to return cluster ID as well, which is non-zero on mentioned
> SoCs and so breaks the calculation in GIC driver.
> 
> This patch fixes this by masking out cluster ID in CPU offset
> calculation so that only core ID is considered. Multi-cluster Exynos
> SoCs already have banked GIC implementations, so this simple fix should
> be enough.
> 
> Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
> Reported-by: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
> Signed-off-by: Tomasz Figa <t.figa at samsung.com>
> ---
>  drivers/irqchip/irq-gic.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index ddee133..5c15a09 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -40,6 +40,7 @@
>  #include <linux/irqchip/chained_irq.h>
>  #include <linux/irqchip/arm-gic.h>

Applied to irqchip/urgent and Cc'd to stable for v3.3+

thx,

Jason.