mach-ux500: DB8500 PMU support
Rabin Vincent [Tue, 8 Feb 2011 03:54:37 +0000 (08:54 +0530)]
DB8500 has irqs from two cores ORed into one. Implement a
workaround to handle this by bouncing the interrupt by setting
the affinity to the other core when the interrupt appears to
be spurious on the current core.

Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/mach-ux500/cpu-db8500.c

index 1748fbc..5c0fabf 100644 (file)
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/amba/bus.h>
+#include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/gpio.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 
 #include <asm/mach/map.h>
+#include <asm/pmu.h>
 #include <mach/hardware.h>
 #include <mach/setup.h>
 #include <mach/devices.h>
 
 #include "devices-db8500.h"
 
-static struct platform_device *platform_devs[] __initdata = {
-       &u8500_dma40_device,
-};
-
 /* minimum static i/o mapping required to boot U8500 platforms */
 static struct map_desc u8500_uart_io_desc[] __initdata = {
        __IO_DEV_DESC(U8500_UART0_BASE, SZ_4K),
@@ -89,6 +87,51 @@ void __init u8500_map_io(void)
                iotable_init(u8500_v2_io_desc, ARRAY_SIZE(u8500_v2_io_desc));
 }
 
+static struct resource db8500_pmu_resources[] = {
+       [0] = {
+               .start          = IRQ_DB8500_PMU,
+               .end            = IRQ_DB8500_PMU,
+               .flags          = IORESOURCE_IRQ,
+       },
+};
+
+/*
+ * The PMU IRQ lines of two cores are wired together into a single interrupt.
+ * Bounce the interrupt to the other core if it's not ours.
+ */
+static irqreturn_t db8500_pmu_handler(int irq, void *dev, irq_handler_t handler)
+{
+       irqreturn_t ret = handler(irq, dev);
+       int other = !smp_processor_id();
+
+       if (ret == IRQ_NONE && cpu_online(other))
+               irq_set_affinity(irq, cpumask_of(other));
+
+       /*
+        * We should be able to get away with the amount of IRQ_NONEs we give,
+        * while still having the spurious IRQ detection code kick in if the
+        * interrupt really starts hitting spuriously.
+        */
+       return ret;
+}
+
+static struct arm_pmu_platdata db8500_pmu_platdata = {
+       .handle_irq             = db8500_pmu_handler,
+};
+
+static struct platform_device db8500_pmu_device = {
+       .name                   = "arm-pmu",
+       .id                     = ARM_PMU_DEVICE_CPU,
+       .num_resources          = ARRAY_SIZE(db8500_pmu_resources),
+       .resource               = db8500_pmu_resources,
+       .dev.platform_data      = &db8500_pmu_platdata,
+};
+
+static struct platform_device *platform_devs[] __initdata = {
+       &u8500_dma40_device,
+       &db8500_pmu_device,
+};
+
 static resource_size_t __initdata db8500_gpio_base[] = {
        U8500_GPIOBANK0_BASE,
        U8500_GPIOBANK1_BASE,