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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2016-07-08 09:37:08 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2016-07-17 09:42:45 +0300
commitd74361881f0dfe5f9dcac37d1b753a15a2345d8c (patch)
tree49713088a40028b016f84e4fb226b855a76b8f8b /arch/powerpc/sysdev
parent1d607bb3bd60f404d1ceb0d6ebceadf261068422 (diff)
downloadlinux-d74361881f0dfe5f9dcac37d1b753a15a2345d8c.tar.xz
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: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/sysdev')
-rw-r--r--arch/powerpc/sysdev/xics/Makefile2
-rw-r--r--arch/powerpc/sysdev/xics/icp-opal.c144
-rw-r--r--arch/powerpc/sysdev/xics/xics-common.c5
3 files changed, 149 insertions, 2 deletions
diff --git a/arch/powerpc/sysdev/xics/Makefile b/arch/powerpc/sysdev/xics/Makefile
index c606aa8ba60a..5d7f5a6564de 100644
--- a/arch/powerpc/sysdev/xics/Makefile
+++ b/arch/powerpc/sysdev/xics/Makefile
@@ -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
diff --git a/arch/powerpc/sysdev/xics/icp-opal.c b/arch/powerpc/sysdev/xics/icp-opal.c
new file mode 100644
index 000000000000..57d72f10a97f
--- /dev/null
+++ b/arch/powerpc/sysdev/xics/icp-opal.c
@@ -0,0 +1,144 @@
+/*
+ * 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;
+}
+
diff --git a/arch/powerpc/sysdev/xics/xics-common.c b/arch/powerpc/sysdev/xics/xics-common.c
index 47e43b7b076b..a795a5f0301c 100644
--- a/arch/powerpc/sysdev/xics/xics-common.c
+++ b/arch/powerpc/sysdev/xics/xics-common.c
@@ -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;