powerpc/powernv: Add OPAL ICS backend

OPAL handles HW access to the various ICS or equivalent chips
for us (with the exception of p5ioc2 based HEA which uses a

different backend) similarily to what RTAS does on pSeries.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

3 files changed, 247 insertions, 6 deletions

diff --git a/arch/powerpc/sysdev/xics/Makefile b/arch/powerpc/sysdev/xics/Makefile
index b75a6059337..c606aa8ba60 100644
--- a/arch/powerpc/sysdev/xics/Makefile
+++ b/arch/powerpc/sysdev/xics/Makefile
@@ -4,3 +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
diff --git a/arch/powerpc/sysdev/xics/ics-opal.c b/arch/powerpc/sysdev/xics/ics-opal.c
new file mode 100644
index 00000000000..f7e8609df0d
--- /dev/null
+++ b/arch/powerpc/sysdev/xics/ics-opal.c
@@ -0,0 +1,244 @@
+/*
+ * ICS backend for OPAL managed interrupts.
+ *
+ * Copyright 2011 IBM Corp.
+ *
+ * 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.
+ */
+
+#undef DEBUG
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/irq.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/spinlock.h>
+#include <linux/msi.h>
+
+#include <asm/prom.h>
+#include <asm/smp.h>
+#include <asm/machdep.h>
+#include <asm/irq.h>
+#include <asm/errno.h>
+#include <asm/xics.h>
+#include <asm/opal.h>
+#include <asm/firmware.h>
+
+static int ics_opal_mangle_server(int server)
+{
+        /* No link for now */
+        return server << 2;
+}
+
+static int ics_opal_unmangle_server(int server)
+{
+        /* No link for now */
+        return server >> 2;
+}
+
+static void ics_opal_unmask_irq(struct irq_data *d)
+{
+        unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
+        int64_t rc;
+        int server;
+
+        pr_devel("ics-hal: unmask virq %d [hw 0x%x]\n", d->irq, hw_irq);
+
+        if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
+                return;
+
+        server = xics_get_irq_server(d->irq, d->affinity, 0);
+        server = ics_opal_mangle_server(server);
+
+        rc = opal_set_xive(hw_irq, server, DEFAULT_PRIORITY);
+        if (rc != OPAL_SUCCESS)
+                pr_err("%s: opal_set_xive(irq=%d [hw 0x%x] server=%x)"
+                       " error %lld\n",
+                       __func__, d->irq, hw_irq, server, rc);
+}
+
+static unsigned int ics_opal_startup(struct irq_data *d)
+{
+#ifdef CONFIG_PCI_MSI
+        /*
+         * The generic MSI code returns with the interrupt disabled on the
+         * card, using the MSI mask bits. Firmware doesn't appear to unmask
+         * at that level, so we do it here by hand.
+         */
+        if (d->msi_desc)
+                unmask_msi_irq(d);
+#endif
+
+        /* unmask it */
+        ics_opal_unmask_irq(d);
+        return 0;
+}
+
+static void ics_opal_mask_real_irq(unsigned int hw_irq)
+{
+        int server = ics_opal_mangle_server(xics_default_server);
+        int64_t rc;
+
+        if (hw_irq == XICS_IPI)
+                return;
+
+        /* Have to set XIVE to 0xff to be able to remove a slot */
+        rc = opal_set_xive(hw_irq, server, 0xff);
+        if (rc != OPAL_SUCCESS)
+                pr_err("%s: opal_set_xive(0xff) irq=%u returned %lld\n",
+                       __func__, hw_irq, rc);
+}
+
+static void ics_opal_mask_irq(struct irq_data *d)
+{
+        unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
+
+        pr_devel("ics-hal: mask virq %d [hw 0x%x]\n", d->irq, hw_irq);
+
+        if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
+                return;
+        ics_opal_mask_real_irq(hw_irq);
+}
+
+static int ics_opal_set_affinity(struct irq_data *d,
+                                 const struct cpumask *cpumask,
+                                 bool force)
+{
+        unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
+        int16_t server;
+        int8_t priority;
+        int64_t rc;
+        int wanted_server;
+
+        if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
+                return -1;
+
+        rc = opal_get_xive(hw_irq, &server, &priority);
+        if (rc != OPAL_SUCCESS) {
+                pr_err("%s: opal_set_xive(irq=%d [hw 0x%x] server=%x)"
+                       " error %lld\n",
+                       __func__, d->irq, hw_irq, server, rc);
+                return -1;
+        }
+
+        wanted_server = xics_get_irq_server(d->irq, cpumask, 1);
+        if (wanted_server < 0) {
+                char cpulist[128];
+                cpumask_scnprintf(cpulist, sizeof(cpulist), cpumask);
+                pr_warning("%s: No online cpus in the mask %s for irq %d\n",
+                           __func__, cpulist, d->irq);
+                return -1;
+        }
+        server = ics_opal_mangle_server(wanted_server);
+
+        pr_devel("ics-hal: set-affinity irq %d [hw 0x%x] server: 0x%x/0x%x\n",
+                 d->irq, hw_irq, wanted_server, server);
+
+        rc = opal_set_xive(hw_irq, server, priority);
+        if (rc != OPAL_SUCCESS) {
+                pr_err("%s: opal_set_xive(irq=%d [hw 0x%x] server=%x)"
+                       " error %lld\n",
+                       __func__, d->irq, hw_irq, server, rc);
+                return -1;
+        }
+        return 0;
+}
+
+static struct irq_chip ics_opal_irq_chip = {
+        .name = "OPAL ICS",
+        .irq_startup = ics_opal_startup,
+        .irq_mask = ics_opal_mask_irq,
+        .irq_unmask = ics_opal_unmask_irq,
+        .irq_eoi = NULL, /* Patched at init time */
+        .irq_set_affinity = ics_opal_set_affinity
+};
+
+static int ics_opal_map(struct ics *ics, unsigned int virq);
+static void ics_opal_mask_unknown(struct ics *ics, unsigned long vec);
+static long ics_opal_get_server(struct ics *ics, unsigned long vec);
+
+static int ics_opal_host_match(struct ics *ics, struct device_node *node)
+{
+        return 1;
+}
+
+/* Only one global & state struct ics */
+static struct ics ics_hal = {
+        .map            = ics_opal_map,
+        .mask_unknown   = ics_opal_mask_unknown,
+        .get_server     = ics_opal_get_server,
+        .host_match     = ics_opal_host_match,
+};
+
+static int ics_opal_map(struct ics *ics, unsigned int virq)
+{
+        unsigned int hw_irq = (unsigned int)virq_to_hw(virq);
+        int64_t rc;
+        int16_t server;
+        int8_t priority;
+
+        if (WARN_ON(hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS))
+                return -EINVAL;
+
+        /* Check if HAL knows about this interrupt */
+        rc = opal_get_xive(hw_irq, &server, &priority);
+        if (rc != OPAL_SUCCESS)
+                return -ENXIO;
+
+        irq_set_chip_and_handler(virq, &ics_opal_irq_chip, handle_fasteoi_irq);
+        irq_set_chip_data(virq, &ics_hal);
+
+        return 0;
+}
+
+static void ics_opal_mask_unknown(struct ics *ics, unsigned long vec)
+{
+        int64_t rc;
+        int16_t server;
+        int8_t priority;
+
+        /* Check if HAL knows about this interrupt */
+        rc = opal_get_xive(vec, &server, &priority);
+        if (rc != OPAL_SUCCESS)
+                return;
+
+        ics_opal_mask_real_irq(vec);
+}
+
+static long ics_opal_get_server(struct ics *ics, unsigned long vec)
+{
+        int64_t rc;
+        int16_t server;
+        int8_t priority;
+
+        /* Check if HAL knows about this interrupt */
+        rc = opal_get_xive(vec, &server, &priority);
+        if (rc != OPAL_SUCCESS)
+                return -1;
+        return ics_opal_unmangle_server(server);
+}
+
+int __init ics_opal_init(void)
+{
+        if (!firmware_has_feature(FW_FEATURE_OPAL))
+                return -ENODEV;
+
+        /* We need to patch our irq chip's EOI to point to the
+         * right ICP
+         */
+        ics_opal_irq_chip.irq_eoi = icp_ops->eoi;
+
+        /* Register ourselves */
+        xics_register_ics(&ics_hal);
+
+        pr_info("ICS OPAL backend registered\n");
+
+        return 0;
+}
diff --git a/arch/powerpc/sysdev/xics/xics-common.c b/arch/powerpc/sysdev/xics/xics-common.c
index 445c5a01b76..3d93a8ded0f 100644
--- a/arch/powerpc/sysdev/xics/xics-common.c
+++ b/arch/powerpc/sysdev/xics/xics-common.c
@@ -409,14 +409,10 @@ void __init xics_init(void)
         int rc = -1;
 
         /* Fist locate ICP */
-#ifdef CONFIG_PPC_ICP_HV
         if (firmware_has_feature(FW_FEATURE_LPAR))
                 rc = icp_hv_init();
-#endif
-#ifdef CONFIG_PPC_ICP_NATIVE
         if (rc < 0)
                 rc = icp_native_init();
-#endif
         if (rc < 0) {
                 pr_warning("XICS: Cannot find a Presentation Controller !\n");
                 return;
@@ -429,9 +425,9 @@ void __init xics_init(void)
         xics_ipi_chip.irq_eoi = icp_ops->eoi;
 
         /* Now locate ICS */
-#ifdef CONFIG_PPC_ICS_RTAS
         rc = ics_rtas_init();
-#endif
+        if (rc < 0)
+                rc = ics_opal_init();
         if (rc < 0)
                 pr_warning("XICS: Cannot find a Source Controller !\n");