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Commit d7436188 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Michael Ellerman
Browse files

powerpc/xics: Add ICP OPAL backend 



This adds a new XICS backend that uses OPAL calls, which can be
used when we don't have native support for the platform interrupt
controller.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 1d607bb3

arch/powerpc/include/asm/xics.h

+6 −0
Original line number Diff line number Diff line
@@ -42,6 +42,12 @@ extern int icp_hv_init(void); 
static inline int icp_hv_init(void) { return -ENODEV; }

#endif



#ifdef CONFIG_PPC_POWERNV

extern int icp_opal_init(void);

#else

static inline int icp_opal_init(void) { return -ENODEV; }

#endif



/* ICP ops */

struct icp_ops {

	unsigned int (*get_irq)(void);

arch/powerpc/sysdev/xics/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -4,4 +4,4 @@ obj-y += xics-common.o 
obj-$(CONFIG_PPC_ICP_NATIVE)	+= icp-native.o

obj-$(CONFIG_PPC_ICP_HV)	+= icp-hv.o

obj-$(CONFIG_PPC_ICS_RTAS)	+= ics-rtas.o

obj-$(CONFIG_PPC_POWERNV)	+= ics-opal.o
 
obj-$(CONFIG_PPC_POWERNV)	+= ics-opal.o icp-opal.o

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

0 → 100644
+144 −0
Original line number Diff line number Diff line 
/*

 * Copyright 2016 IBM Corporation.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version

 * 2 of the License, or (at your option) any later version.

 */

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/irq.h>

#include <linux/smp.h>

#include <linux/interrupt.h>

#include <linux/cpu.h>

#include <linux/of.h>



#include <asm/smp.h>

#include <asm/irq.h>

#include <asm/errno.h>

#include <asm/xics.h>

#include <asm/io.h>

#include <asm/opal.h>



static void icp_opal_teardown_cpu(void)

{

	int cpu = smp_processor_id();



	/* Clear any pending IPI */

	opal_int_set_mfrr(cpu, 0xff);

}



static void icp_opal_flush_ipi(void)

{

	/*

	 * We take the ipi irq but and never return so we need to EOI the IPI,

	 * but want to leave our priority 0.

	 *

	 * Should we check all the other interrupts too?

	 * Should we be flagging idle loop instead?

	 * Or creating some task to be scheduled?

	 */

	opal_int_eoi((0x00 << 24) | XICS_IPI);

}



static unsigned int icp_opal_get_irq(void)

{

	unsigned int xirr;

	unsigned int vec;

	unsigned int irq;

	int64_t rc;



	rc = opal_int_get_xirr(&xirr, false);

	if (rc < 0)

		return NO_IRQ;

	xirr = be32_to_cpu(xirr);

	vec = xirr & 0x00ffffff;

	if (vec == XICS_IRQ_SPURIOUS)

		return NO_IRQ;



	irq = irq_find_mapping(xics_host, vec);

	if (likely(irq != NO_IRQ)) {

		xics_push_cppr(vec);

		return irq;

	}



	/* We don't have a linux mapping, so have rtas mask it. */

	xics_mask_unknown_vec(vec);



	/* We might learn about it later, so EOI it */

	opal_int_eoi(xirr);



	return NO_IRQ;

}



static void icp_opal_set_cpu_priority(unsigned char cppr)

{

	xics_set_base_cppr(cppr);

	opal_int_set_cppr(cppr);

	iosync();

}



static void icp_opal_eoi(struct irq_data *d)

{

	unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);

	int64_t rc;



	iosync();

	rc = opal_int_eoi((xics_pop_cppr() << 24) | hw_irq);



	/*

	 * EOI tells us whether there are more interrupts to fetch.

	 *

	 * Some HW implementations might not be able to send us another

	 * external interrupt in that case, so we force a replay.

	 */

	if (rc > 0)

		force_external_irq_replay();

}



#ifdef CONFIG_SMP



static void icp_opal_cause_ipi(int cpu, unsigned long data)

{

	opal_int_set_mfrr(cpu, IPI_PRIORITY);

}



static irqreturn_t icp_opal_ipi_action(int irq, void *dev_id)

{

	int cpu = smp_processor_id();



	opal_int_set_mfrr(cpu, 0xff);



	return smp_ipi_demux();

}



#endif /* CONFIG_SMP */



static const struct icp_ops icp_opal_ops = {

	.get_irq	= icp_opal_get_irq,

	.eoi		= icp_opal_eoi,

	.set_priority	= icp_opal_set_cpu_priority,

	.teardown_cpu	= icp_opal_teardown_cpu,

	.flush_ipi	= icp_opal_flush_ipi,

#ifdef CONFIG_SMP

	.ipi_action	= icp_opal_ipi_action,

	.cause_ipi	= icp_opal_cause_ipi,

#endif

};



int icp_opal_init(void)

{

	struct device_node *np;



	np = of_find_compatible_node(NULL, NULL, "ibm,opal-intc");

	if (!np)

		return -ENODEV;



	icp_ops = &icp_opal_ops;



	printk("XICS: Using OPAL ICP fallbacks\n");



	return 0;

}

arch/powerpc/sysdev/xics/xics-common.c

+4 −1
Original line number Diff line number Diff line
@@ -404,8 +404,11 @@ void __init xics_init(void) 
	/* Fist locate ICP */

	if (firmware_has_feature(FW_FEATURE_LPAR))

		rc = icp_hv_init();

	if (rc < 0)

	if (rc < 0) {

		rc = icp_native_init();

		if (rc == -ENODEV)

		    rc = icp_opal_init();

	}

	if (rc < 0) {

		pr_warning("XICS: Cannot find a Presentation Controller !\n");

		return;