From: Benjamin Herrenschmidt <b...@kernel.crashing.org>

This is a simple native ICS backend that matches the layout of
the Microwatt implementation of ICS.

Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Signed-off-by: Paul Mackerras <pau...@ozlabs.org>
---
 arch/powerpc/boot/dts/microwatt.dts      |  18 ++
 arch/powerpc/platforms/microwatt/Kconfig |   2 +
 arch/powerpc/platforms/microwatt/setup.c |   8 +
 arch/powerpc/sysdev/xics/Kconfig         |   3 +
 arch/powerpc/sysdev/xics/Makefile        |   1 +
 arch/powerpc/sysdev/xics/ics-native.c    | 257 +++++++++++++++++++++++
 arch/powerpc/sysdev/xics/xics-common.c   |   2 +
 7 files changed, 291 insertions(+)
 create mode 100644 arch/powerpc/sysdev/xics/ics-native.c

diff --git a/arch/powerpc/boot/dts/microwatt.dts 
b/arch/powerpc/boot/dts/microwatt.dts
index 9b6140c90370..04e5dd92270e 100644
--- a/arch/powerpc/boot/dts/microwatt.dts
+++ b/arch/powerpc/boot/dts/microwatt.dts
@@ -99,7 +99,25 @@ soc@c0000000 {
                compatible = "simple-bus";
                #address-cells = <1>;
                #size-cells = <1>;
+               interrupt-parent = <&ICS>;
 
                ranges = <0 0 0xc0000000 0x40000000>;
+
+               interrupt-controller@4000 {
+                       compatible = "openpower,xics-presentation", 
"ibm,ppc-xicp";
+                       ibm,interrupt-server-ranges = <0x0 0x1>;
+                       reg = <0x4000 0x100>;
+               };
+
+               ICS: interrupt-controller@5000 {
+                       compatible = "openpower,xics-sources";
+                       interrupt-controller;
+                       interrupt-ranges = <0x10 0x10>;
+                       reg = <0x5000 0x100>;
+                       #address-cells = <0>;
+                       #size-cells = <0>;
+                       #interrupt-cells = <2>;
+               };
+
        };
 };
diff --git a/arch/powerpc/platforms/microwatt/Kconfig 
b/arch/powerpc/platforms/microwatt/Kconfig
index 3be01e78ce57..b52c869c0eb8 100644
--- a/arch/powerpc/platforms/microwatt/Kconfig
+++ b/arch/powerpc/platforms/microwatt/Kconfig
@@ -3,6 +3,8 @@ config PPC_MICROWATT
        depends on PPC_BOOK3S_64 && !SMP
        bool "Microwatt SoC platform"
        select PPC_XICS
+       select PPC_ICS_NATIVE
+       select PPC_ICP_NATIVE
        select PPC_NATIVE
        help
           This option enables support for FPGA-based Microwatt implementations.
diff --git a/arch/powerpc/platforms/microwatt/setup.c 
b/arch/powerpc/platforms/microwatt/setup.c
index 5af4adf881bc..1c1b7791fa57 100644
--- a/arch/powerpc/platforms/microwatt/setup.c
+++ b/arch/powerpc/platforms/microwatt/setup.c
@@ -10,8 +10,15 @@
 #include <linux/init.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
+
 #include <asm/machdep.h>
 #include <asm/time.h>
+#include <asm/xics.h>
+
+static void __init microwatt_init_IRQ(void)
+{
+       xics_init();
+}
 
 static int __init microwatt_probe(void)
 {
@@ -27,5 +34,6 @@ machine_arch_initcall(microwatt, microwatt_populate);
 define_machine(microwatt) {
        .name                   = "microwatt",
        .probe                  = microwatt_probe,
+       .init_IRQ               = microwatt_init_IRQ,
        .calibrate_decr         = generic_calibrate_decr,
 };
diff --git a/arch/powerpc/sysdev/xics/Kconfig b/arch/powerpc/sysdev/xics/Kconfig
index 304614c920aa..063d9195891f 100644
--- a/arch/powerpc/sysdev/xics/Kconfig
+++ b/arch/powerpc/sysdev/xics/Kconfig
@@ -12,3 +12,6 @@ config PPC_ICP_HV
 
 config PPC_ICS_RTAS
        def_bool n
+
+config PPC_ICS_NATIVE
+       def_bool n
diff --git a/arch/powerpc/sysdev/xics/Makefile 
b/arch/powerpc/sysdev/xics/Makefile
index ba1e3117b1c0..747063927c6c 100644
--- a/arch/powerpc/sysdev/xics/Makefile
+++ b/arch/powerpc/sysdev/xics/Makefile
@@ -4,4 +4,5 @@ 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_ICS_NATIVE)   += ics-native.o
 obj-$(CONFIG_PPC_POWERNV)      += ics-opal.o icp-opal.o
diff --git a/arch/powerpc/sysdev/xics/ics-native.c 
b/arch/powerpc/sysdev/xics/ics-native.c
new file mode 100644
index 000000000000..d450502f4053
--- /dev/null
+++ b/arch/powerpc/sysdev/xics/ics-native.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ICS backend for OPAL managed interrupts.
+ *
+ * Copyright 2011 IBM Corp.
+ */
+
+//#define 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 <linux/list.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>
+
+struct ics_native {
+       struct ics              ics;
+       struct device_node      *node;
+       void __iomem            *base;
+       u32                     ibase;
+       u32                     icount;
+};
+#define to_ics_native(_ics)     container_of(_ics, struct ics_native, ics)
+
+static void __iomem *ics_native_xive(struct ics_native *in, unsigned int vec)
+{
+       return in->base + 0x800 + ((vec - in->ibase) << 2);
+}
+
+static void ics_native_unmask_irq(struct irq_data *d)
+{
+       unsigned int vec = (unsigned int)irqd_to_hwirq(d);
+       struct ics *ics = irq_data_get_irq_chip_data(d);
+       struct ics_native *in = to_ics_native(ics);
+       unsigned int server;
+
+       pr_devel("ics-native: unmask virq %d [hw 0x%x]\n", d->irq, vec);
+
+       if (vec < in->ibase || vec >= (in->ibase + in->icount))
+               return;
+
+       server = xics_get_irq_server(d->irq, irq_data_get_affinity_mask(d), 0);
+       out_be32(ics_native_xive(in, vec), (server << 8) | DEFAULT_PRIORITY);
+}
+
+static unsigned int ics_native_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 (irq_data_get_msi_desc(d))
+               pci_msi_unmask_irq(d);
+#endif
+
+       /* unmask it */
+       ics_native_unmask_irq(d);
+       return 0;
+}
+
+static void ics_native_do_mask(struct ics_native *in, unsigned int vec)
+{
+       out_be32(ics_native_xive(in, vec), 0xff);
+}
+
+static void ics_native_mask_irq(struct irq_data *d)
+{
+       unsigned int vec = (unsigned int)irqd_to_hwirq(d);
+       struct ics *ics = irq_data_get_irq_chip_data(d);
+       struct ics_native *in = to_ics_native(ics);
+
+       pr_devel("ics-native: mask virq %d [hw 0x%x]\n", d->irq, vec);
+
+       if (vec < in->ibase || vec >= (in->ibase + in->icount))
+               return;
+       ics_native_do_mask(in, vec);
+}
+
+static int ics_native_set_affinity(struct irq_data *d,
+                                  const struct cpumask *cpumask,
+                                  bool force)
+{
+       unsigned int vec = (unsigned int)irqd_to_hwirq(d);
+       struct ics *ics = irq_data_get_irq_chip_data(d);
+       struct ics_native *in = to_ics_native(ics);
+       int server;
+       u32 xive;
+
+       if (vec < in->ibase || vec >= (in->ibase + in->icount))
+               return -EINVAL;
+
+       server = xics_get_irq_server(d->irq, cpumask, 1);
+       if (server == -1) {
+               pr_warn("%s: No online cpus in the mask %*pb for irq %d\n",
+                       __func__, cpumask_pr_args(cpumask), d->irq);
+               return -1;
+       }
+
+       xive = in_be32(ics_native_xive(in, vec));
+       xive = (xive & 0xff) | (server << 8);
+       out_be32(ics_native_xive(in, vec), xive);
+
+       return IRQ_SET_MASK_OK;
+}
+
+static struct irq_chip ics_native_irq_chip = {
+       .name = "ICS",
+       .irq_startup            = ics_native_startup,
+       .irq_mask               = ics_native_mask_irq,
+       .irq_unmask             = ics_native_unmask_irq,
+       .irq_eoi                = NULL, /* Patched at init time */
+       .irq_set_affinity       = ics_native_set_affinity,
+       .irq_set_type           = xics_set_irq_type,
+       .irq_retrigger          = xics_retrigger,
+};
+
+static int ics_native_map(struct ics *ics, unsigned int virq)
+{
+       unsigned int vec = (unsigned int)virq_to_hw(virq);
+       struct ics_native *in = to_ics_native(ics);
+
+       pr_devel("%s: vec=0x%x\n", __func__, vec);
+
+       if (vec < in->ibase || vec >= (in->ibase + in->icount))
+               return -EINVAL;
+
+       irq_set_chip_and_handler(virq, &ics_native_irq_chip, 
handle_fasteoi_irq);
+       irq_set_chip_data(virq, ics);
+
+       return 0;
+}
+
+static void ics_native_mask_unknown(struct ics *ics, unsigned long vec)
+{
+       struct ics_native *in = to_ics_native(ics);
+
+       if (vec < in->ibase || vec >= (in->ibase + in->icount))
+               return;
+
+       ics_native_do_mask(in, vec);
+}
+
+static long ics_native_get_server(struct ics *ics, unsigned long vec)
+{
+       struct ics_native *in = to_ics_native(ics);
+       u32 xive;
+
+       if (vec < in->ibase || vec >= (in->ibase + in->icount))
+               return -EINVAL;
+
+       xive = in_be32(ics_native_xive(in, vec));
+       return (xive >> 8) & 0xfff;
+}
+
+static int ics_native_host_match(struct ics *ics, struct device_node *node)
+{
+       struct ics_native *in = to_ics_native(ics);
+
+       return in->node == node;
+}
+
+static struct ics ics_native_template = {
+       .map            = ics_native_map,
+       .mask_unknown   = ics_native_mask_unknown,
+       .get_server     = ics_native_get_server,
+       .host_match     = ics_native_host_match,
+};
+
+static int __init ics_native_add_one(struct device_node *np)
+{
+       struct ics_native *ics;
+       u32 ranges[2];
+       int rc, count;
+
+       ics = kzalloc(sizeof(struct ics_native), GFP_KERNEL);
+       if (!ics)
+               return -ENOMEM;
+       ics->node = of_node_get(np);
+       memcpy(&ics->ics, &ics_native_template, sizeof(struct ics));
+
+       ics->base = of_iomap(np, 0);
+       if (!ics->base) {
+               pr_err("Failed to map %pOFP\n", np);
+               rc = -ENOMEM;
+               goto fail;
+       }
+
+       count = of_property_count_u32_elems(np, "interrupt-ranges");
+       if (count < 2 || count & 1) {
+               pr_err("Failed to read interrupt-ranges of %pOFP\n", np);
+               rc = -EINVAL;
+               goto fail;
+       }
+       if (count > 2) {
+               pr_warn("ICS %pOFP has %d ranges, only one supported\n",
+                       np, count >> 1);
+       }
+       rc = of_property_read_u32_array(np, "interrupt-ranges",
+                                       ranges, 2);
+       if (rc) {
+               pr_err("Failed to read interrupt-ranges of %pOFP\n", np);
+               goto fail;
+       }
+       ics->ibase = ranges[0];
+       ics->icount = ranges[1];
+
+       pr_info("ICS native initialized for sources %d..%d\n",
+               ics->ibase, ics->ibase + ics->icount - 1);
+
+       /* Register ourselves */
+       xics_register_ics(&ics->ics);
+
+       return 0;
+fail:
+       of_node_put(ics->node);
+       kfree(ics);
+       return rc;
+}
+
+int __init ics_native_init(void)
+{
+       struct device_node *ics;
+       bool found_one = false;
+
+       /* We need to patch our irq chip's EOI to point to the
+        * right ICP
+        */
+       ics_native_irq_chip.irq_eoi = icp_ops->eoi;
+
+       /* Find native ICS in the device-tree */
+       for_each_compatible_node(ics, NULL, "openpower,xics-sources") {
+               if (ics_native_add_one(ics) == 0)
+                       found_one = true;
+       }
+
+       if (found_one)
+               pr_info("ICS native backend registered\n");
+
+       return found_one ? 0 : -ENODEV;
+}
diff --git a/arch/powerpc/sysdev/xics/xics-common.c 
b/arch/powerpc/sysdev/xics/xics-common.c
index 7e4305c01bac..de41ab91f793 100644
--- a/arch/powerpc/sysdev/xics/xics-common.c
+++ b/arch/powerpc/sysdev/xics/xics-common.c
@@ -476,6 +476,8 @@ void __init xics_init(void)
        rc = ics_rtas_init();
        if (rc < 0)
                rc = ics_opal_init();
+       if (rc < 0)
+               rc = ics_native_init();
        if (rc < 0)
                pr_warn("XICS: Cannot find a Source Controller !\n");
 
-- 
2.31.1

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