powerpc/xics: Work around limitations of OPAL XICS priority handling (9ba6c38e) · Commits · e / devices / android_kernel_fairphone_FP3

arch/powerpc/sysdev/xics/icp-opal.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -91,6 +91,16 @@ static unsigned int icp_opal_get_irq(void)

		static void icp_opal_set_cpu_priority(unsigned char cppr)
		{
		/*
		* Here be dragons. The caller has asked to allow only IPI's and not
		* external interrupts. But OPAL XIVE doesn't support that. So instead
		* of allowing no interrupts allow all. That's still not right, but
		* currently the only caller who does this is xics_migrate_irqs_away()
		* and it works in that case.
		*/
		if (cppr >= DEFAULT_PRIORITY)
		cppr = LOWEST_PRIORITY;

		xics_set_base_cppr(cppr);
		opal_int_set_cppr(cppr);
		iosync();

+14 −3

Original line number	Diff line number	Diff line
		@@ -20,6 +20,7 @@
		#include <linux/of.h>
		#include <linux/slab.h>
		#include <linux/spinlock.h>
		#include <linux/delay.h>

		#include <asm/prom.h>
		#include <asm/io.h>
		@@ -198,9 +199,6 @@ void xics_migrate_irqs_away(void)
		/* Remove ourselves from the global interrupt queue */
		xics_set_cpu_giq(xics_default_distrib_server, 0);

		/* Allow IPIs again... */
		icp_ops->set_priority(DEFAULT_PRIORITY);

		for_each_irq_desc(virq, desc) {
		struct irq_chip *chip;
		long server;
		@@ -255,6 +253,19 @@ void xics_migrate_irqs_away(void)
		unlock:
		raw_spin_unlock_irqrestore(&desc->lock, flags);
		}

		/* Allow "sufficient" time to drop any inflight IRQ's */
		mdelay(5);

		/*
		* Allow IPIs again. This is done at the very end, after migrating all
		* interrupts, the expectation is that we'll only get woken up by an IPI
		* interrupt beyond this point, but leave externals masked just to be
		* safe. If we're using icp-opal this may actually allow all
		* interrupts anyway, but that should be OK.
		*/
		icp_ops->set_priority(DEFAULT_PRIORITY);

		}
		#endif /* CONFIG_HOTPLUG_CPU */