[Qemu-arm] [PATCH v2 09/11] hw/acpi: Add ACPI Generic Event Device Support

[Shameer Kolothum]

From: Samuel Ortiz <address@hidden>

The ACPI Generic Event Device (GED) is a hardware-reduced specific
device that handles all platform events, including the hotplug ones.
This patch generate the AML code that defines GEDs.
Platforms need to specify their own GedEvent array to describe what kind
of events they want to support through GED. The build_ged_aml routine
takes a GedEvent array that maps a specific GED event to an IRQ number.
Then we use that array to build both the _CRS and the _EVT section
of the GED device.

This is in preparation for making use of GED for ARM/virt
platform and for now supports only memory hotplug.

Signed-off-by: Samuel Ortiz <address@hidden>
Signed-off-by: Sebastien Boeuf <address@hidden>
Signed-off-by: Shameer Kolothum <address@hidden>
---
 hw/acpi/Makefile.objs |   1 +
 hw/acpi/ged.c         | 198 ++++++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/acpi/ged.h |  61 ++++++++++++++++
 3 files changed, 260 insertions(+)
 create mode 100644 hw/acpi/ged.c
 create mode 100644 include/hw/acpi/ged.h

diff --git a/hw/acpi/Makefile.objs b/hw/acpi/Makefile.objs
index 2d46e37..6cf572b 100644
--- a/hw/acpi/Makefile.objs
+++ b/hw/acpi/Makefile.objs
@@ -6,6 +6,7 @@ common-obj-$(CONFIG_ACPI_MEMORY_HOTPLUG) += memory_hotplug.o
 common-obj-$(CONFIG_ACPI_CPU_HOTPLUG) += cpu.o
 common-obj-$(CONFIG_ACPI_NVDIMM) += nvdimm.o
 common-obj-$(CONFIG_ACPI_VMGENID) += vmgenid.o
+common-obj-$(CONFIG_ACPI_HW_REDUCED) += ged.o
 common-obj-$(call lnot,$(CONFIG_ACPI_X86)) += acpi-stub.o
 
 common-obj-y += acpi_interface.o
diff --git a/hw/acpi/ged.c b/hw/acpi/ged.c
new file mode 100644
index 0000000..5076fbc
--- /dev/null
+++ b/hw/acpi/ged.c
@@ -0,0 +1,198 @@
+/*
+ *
+ * Copyright (c) 2018 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "hw/acpi/ged.h"
+
+static hwaddr ged_io_base;
+
+static uint64_t ged_read(void *opaque, hwaddr addr, unsigned size)
+{
+    uint64_t val = 0;
+    GEDState *ged_st = opaque;
+
+    switch (addr) {
+    case ACPI_GED_IRQ_SEL_OFFSET:
+        /* Read the selector value and reset it */
+        qemu_mutex_lock(&ged_st->lock);
+        val = ged_st->sel;
+        ged_st->sel = ACPI_GED_IRQ_SEL_INIT;
+        qemu_mutex_unlock(&ged_st->lock);
+        break;
+    default:
+        break;
+    }
+
+    return val;
+}
+
+/* Nothing is expected to be written to the GED memory region */
+static void ged_write(void *opaque, hwaddr addr, uint64_t data,
+                      unsigned int size)
+{
+}
+
+static const MemoryRegionOps ged_ops = {
+    .read = ged_read,
+    .write = ged_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+    },
+};
+
+void acpi_ged_init(MemoryRegion *as, Object *owner, GEDState *ged_st,
+                   hwaddr base_addr, uint32_t ged_irq)
+{
+
+    assert(!ged_io_base);
+
+    ged_io_base = base_addr;
+    ged_st->irq = ged_irq;
+    qemu_mutex_init(&ged_st->lock);
+    memory_region_init_io(&ged_st->io, owner, &ged_ops, ged_st,
+                          "acpi-ged-event", ACPI_GED_REG_LEN);
+    memory_region_add_subregion(as, base_addr, &ged_st->io);
+}
+
+void acpi_ged_event(GEDState *ged_st, qemu_irq *irq, uint32_t ged_irq_sel)
+{
+    /*
+     * Set the GED IRQ selector to the expected device type value. This
+     * way, the ACPI method will be able to trigger the right code based
+     * on a unique IRQ.
+     */
+    qemu_mutex_lock(&ged_st->lock);
+    ged_st->sel |= ged_irq_sel;
+    qemu_mutex_unlock(&ged_st->lock);
+
+    /* Trigger the event by sending an interrupt to the guest. */
+    qemu_irq_pulse(irq[ged_st->irq]);
+}
+
+static Aml *ged_event_aml(GedEvent *event)
+{
+
+    if (!event) {
+        return NULL;
+    }
+
+    switch (event->event) {
+    case GED_MEMORY_HOTPLUG:
+        /* We run a complete memory SCAN when getting a memory hotplug event */
+        return aml_call0("\\_SB.MHPC." MEMORY_SLOT_SCAN_METHOD);
+    default:
+        break;
+    }
+
+    return NULL;
+}
+
+void build_ged_aml(Aml *table, const char *name, uint32_t ged_irq,
+                   GedEvent *events, uint32_t events_size,
+                   AmlRegionSpace rs)
+{
+    Aml *crs = aml_resource_template();
+    Aml *evt, *field;
+    Aml *zero = aml_int(0);
+    Aml *dev = aml_device("%s", name);
+    Aml *irq_sel = aml_local(0);
+    Aml *isel = aml_name(AML_GED_IRQ_SEL);
+    uint32_t i;
+
+    if (!ged_io_base) {
+        return;
+    }
+
+    /* _CRS interrupt */
+    aml_append(crs, aml_interrupt(AML_CONSUMER, AML_EDGE, AML_ACTIVE_HIGH,
+                                  AML_EXCLUSIVE, &ged_irq, 1));
+    /*
+     * For each GED event we:
+     * - Add an interrupt to the CRS section.
+     * - Add a conditional block for each event, inside a while loop.
+     *   This is semantically equivalent to a switch/case implementation.
+     */
+    evt = aml_method("_EVT", 1, AML_SERIALIZED);
+    {
+        Aml *ged_aml;
+        Aml *if_ctx;
+
+        /* Local0 = ISEL */
+        aml_append(evt, aml_store(isel, irq_sel));
+
+        /*
+         * Here we want to call a method for each supported GED event type.
+         * The resulting ASL code looks like:
+         *
+         * Local0 = ISEL
+         * If ((Local0 & irq0) == irq0)
+         * {
+         *     MethodEvent0()
+         * }
+         *
+         * If ((Local0 & irq1) == irq1)
+         * {
+         *     MethodEvent1()
+         * }
+         *
+         * If ((Local0 & irq2) == irq2)
+         * {
+         *     MethodEvent2()
+         * }
+         */
+
+        for (i = 0; i < events_size; i++) {
+            ged_aml = ged_event_aml(&events[i]);
+            if (!ged_aml) {
+                continue;
+            }
+
+            /* If ((Local1 == irq))*/
+            if_ctx = aml_if(aml_equal(aml_and(irq_sel, 
aml_int(events[i].selector), NULL), aml_int(events[i].selector)));
+            {
+                /* AML for this specific type of event */
+                aml_append(if_ctx, ged_aml);
+            }
+
+            /*
+             * We append the first if to the while context.
+             * Other ifs will be elseifs.
+             */
+            aml_append(evt, if_ctx);
+        }
+    }
+
+    aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0013")));
+    aml_append(dev, aml_name_decl("_UID", zero));
+    aml_append(dev, aml_name_decl("_CRS", crs));
+
+    /* Append IO region */
+    aml_append(dev, aml_operation_region(AML_GED_IRQ_REG, rs,
+               aml_int(ged_io_base + ACPI_GED_IRQ_SEL_OFFSET),
+               ACPI_GED_IRQ_SEL_LEN));
+    field = aml_field(AML_GED_IRQ_REG, AML_DWORD_ACC, AML_NOLOCK,
+                      AML_WRITE_AS_ZEROS);
+    aml_append(field, aml_named_field(AML_GED_IRQ_SEL,
+                                      ACPI_GED_IRQ_SEL_LEN * 8));
+    aml_append(dev, field);
+
+    /* Append _EVT method */
+    aml_append(dev, evt);
+
+    aml_append(table, dev);
+}
diff --git a/include/hw/acpi/ged.h b/include/hw/acpi/ged.h
new file mode 100644
index 0000000..60689b0
--- /dev/null
+++ b/include/hw/acpi/ged.h
@@ -0,0 +1,61 @@
+/*
+ *
+ * Copyright (c) 2018 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef HW_ACPI_GED_H
+#define HW_ACPI_GED_H
+
+#include "qemu/osdep.h"
+#include "exec/memory.h"
+#include "hw/acpi/aml-build.h"
+#include "hw/acpi/memory_hotplug.h"
+
+#define ACPI_GED_IRQ_SEL_OFFSET 0x0
+#define ACPI_GED_IRQ_SEL_LEN    0x4
+#define ACPI_GED_IRQ_SEL_INIT   0x0
+#define ACPI_GED_IRQ_SEL_MEM    0x1
+#define ACPI_GED_REG_LEN        0x4
+
+#define GED_DEVICE      "GED"
+#define AML_GED_IRQ_REG "IREG"
+#define AML_GED_IRQ_SEL "ISEL"
+
+typedef struct Aml Aml;
+
+typedef enum {
+    GED_MEMORY_HOTPLUG = 1,
+} GedEventType;
+
+typedef struct GedEvent {
+    uint32_t     selector;
+    GedEventType event;
+} GedEvent;
+
+typedef struct GEDState {
+    MemoryRegion io;
+    uint32_t     sel;
+    uint32_t     irq;
+    QemuMutex    lock;
+} GEDState;
+
+void acpi_ged_init(MemoryRegion *as, Object *owner, GEDState *ged_st,
+                   hwaddr base_addr, uint32_t ged_irq);
+void acpi_ged_event(GEDState *ged_st, qemu_irq *irq, uint32_t ged_irq_sel);
+void build_ged_aml(Aml *table, const char* name, uint32_t ged_irq,
+                   GedEvent *events, uint32_t events_size,
+                   AmlRegionSpace rs);
+
+#endif
-- 
2.7.4