ARM: imx: drop support for irq priorisation

The code for irq priorisation support doesn't have any in-tree users and
the Kconfig description does wrong promises because nowadays irq
handlers are called with irqs disabled, so no high prioritized irq can
interrupt a lower prioritized handler.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/mach-imx/Kconfig

@@ -20,16 +20,6 @@ config ARCH_MXC
 menu "Freescale i.MX support"
 	depends on ARCH_MXC
 
-config MXC_IRQ_PRIOR
-	bool "Use IRQ priority"
-	help
-	  Select this if you want to use prioritized IRQ handling.
-	  This feature prevents higher priority ISR to be interrupted
-	  by lower priority IRQ.
-	  This may be useful in embedded applications, where are strong
-	  requirements for timing.
-	  Say N here, unless you have a specialized requirement.
-
 config MXC_TZIC
 	bool
 

arch/arm/mach-imx/avic.c

@@ -54,28 +54,6 @@
 static void __iomem *avic_base;
 static struct irq_domain *domain;
 
-#ifdef CONFIG_MXC_IRQ_PRIOR
-static int avic_irq_set_priority(unsigned char irq, unsigned char prio)
-{
-	struct irq_data *d = irq_get_irq_data(irq);
-	unsigned int temp;
-	unsigned int mask = 0x0F << irq % 8 * 4;
-
-	irq = d->hwirq;
-
-	if (irq >= AVIC_NUM_IRQS)
-		return -EINVAL;
-
-	temp = __raw_readl(avic_base + AVIC_NIPRIORITY(irq / 8));
-	temp &= ~mask;
-	temp |= prio & mask;
-
-	__raw_writel(temp, avic_base + AVIC_NIPRIORITY(irq / 8));
-
-	return 0;
-}
-#endif
-
 #ifdef CONFIG_FIQ
 static int avic_set_irq_fiq(unsigned int irq, unsigned int type)
 {
@@ -102,9 +80,6 @@ static int avic_set_irq_fiq(unsigned int irq, unsigned int type)
 
 
 static struct mxc_extra_irq avic_extra_irq = {
-#ifdef CONFIG_MXC_IRQ_PRIOR
-	.set_priority = avic_irq_set_priority,
-#endif
 #ifdef CONFIG_FIQ
 	.set_irq_fiq = avic_set_irq_fiq,
 #endif

arch/arm/mach-imx/irq-common.h

@@ -24,7 +24,6 @@
 
 struct mxc_extra_irq
 {
-	int (*set_priority)(unsigned char irq, unsigned char prio);
 	int (*set_irq_fiq)(unsigned int irq, unsigned int type);
 };