The platform bus is a very simple bus, similar to SysBus. However it has
a linear IRQ range that platform devices can attach to. It also provdes
mechanisms to dynamically place IO regions.
This patch implements the bus logic itself.
Signed-off-by: Alexander Graf <ag...@suse.de>
---
hw/platbus/platbus.c | 107 +++++++++++++++++++++++++++++++++++++++++++
include/hw/platbus/platbus.h | 86 ++++++++++++++++++++++++++++++++++
2 files changed, 193 insertions(+)
create mode 100644 hw/platbus/platbus.c
create mode 100644 include/hw/platbus/platbus.h
diff --git a/hw/platbus/platbus.c b/hw/platbus/platbus.c
new file mode 100644
index 0000000..769eb5d
--- /dev/null
+++ b/hw/platbus/platbus.c
@@ -0,0 +1,107 @@
+/*
+ * Generic platform bus with dynamic IRQ and IO placement
+ *
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * Authors: Alexander Graf, <ag...@suse.de>
+ *
+ * This 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.
+ *
+ * The platform bus is a very simple bus, similar to SysBus. However it has
+ * a linear IRQ range that platform devices can attach to. It also provdes
+ * mechanisms to dynamically place IO regions.
+ *
+ * Hence platform bus devices can be easily instantiated using -device from
+ * the command line.
+ */
+
+#include "qemu-common.h"
+#include "hw/platbus/platbus.h"
+
+int platbus_map_irq(PlatBusState *s, uint32_t *irqn, qemu_irq *irq)
+{
+ if (*irqn == (uint32_t)PLATBUS_DYNAMIC) {
+ /* Find the first available IRQ */
+ *irqn = find_first_zero_bit(s->used_irqs, PLATBUS_MAX_IRQ);
+ }
+
+ if ((*irqn >= PLATBUS_MAX_IRQ) || test_and_set_bit(*irqn, s->used_irqs)) {
+ hw_error("PlatBus: IRQ %d is already allocated or no free IRQ left",
+ *irqn);
+ }
+
+ *irq = s->irqs[*irqn];
+
+ return 0;
+}
+
+void platbus_add_irq(PlatBusState *s, uint32_t irqn)
+{
+ clear_bit(irqn, s->used_irqs);
+}
+
+int platbus_map_region(PlatBusState *s, uint64_t *addr, MemoryRegion *mem)
+{
+ uint64_t size = memory_region_size(mem);
+ uint64_t size_pages = (size + ((1 << 12) - 1)) >> 12;
+ int page;
+ int i;
+
+ page = *addr >> 12;
+ if (*addr == (uint64_t)PLATBUS_DYNAMIC) {
+ uint64_t size_pages_align;
+
+ /* Align the region to at least its own size granularity */
+ if (is_power_of_2(size_pages)) {
+ size_pages_align = size_pages;
+ } else {
+ size_pages_align = pow2floor(size_pages) << 1;
+ }
+
+ /* Find the first available region that fits */
+ page = bitmap_find_next_zero_area(s->used_mem, PLATBUS_HOLE_PAGES, 0,
+ size_pages, size_pages_align);
+
+ *addr = (uint64_t)page << 12;
+ }
+
+ if (page >= PLATBUS_HOLE_PAGES || test_bit(page, s->used_mem) ||
+ (find_next_bit(s->used_mem, PLATBUS_HOLE_PAGES, page) < size_pages)) {
+ hw_error("PlatBus: Memory [%"PRIx64":%"PRIx64" is already allocated or
"
+ "no slot left", *addr, size);
+ }
+
+ for (i = page; i < (page + size_pages); i++) {
+ set_bit(i, s->used_mem);
+ }
+
+ memory_region_add_subregion(&s->mem, *addr, mem);
+
+ return 0;
+}
+
+static void platbus_init(Object *obj)
+{
+ PlatBusState *s = PLAT_BUS(obj);
+
+ QTAILQ_INIT(&s->devices);
+ bitmap_fill(s->used_irqs, PLATBUS_MAX_IRQ);
+ memory_region_init(&s->mem, NULL, "platbus", PLATBUS_HOLE);
+}
+
+static const TypeInfo platbus_type_info = {
+ .name = TYPE_PLAT_BUS,
+ .parent = TYPE_BUS,
+ .instance_size = sizeof(PlatBusState),
+ .instance_init = platbus_init,
+};
+
+static void platbus_register_types(void)
+{
+ type_register_static(&platbus_type_info);
+}
+
+type_init(platbus_register_types)
diff --git a/include/hw/platbus/platbus.h b/include/hw/platbus/platbus.h
new file mode 100644
index 0000000..d260fb8
--- /dev/null
+++ b/include/hw/platbus/platbus.h
@@ -0,0 +1,86 @@
+/*
+ * Generic platform bus with dynamic IRQ and IO placement
+ *
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * Authors: Alexander Graf, <ag...@suse.de>
+ *
+ * This 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.
+ */
+
+#ifndef QEMU_HW_PLATBUS_PLATBUS_H
+#define QEMU_HW_PLATBUS_PLATBUS_H
+
+#include "qemu-common.h"
+#include "hw/qdev.h"
+#include "qemu/bitmap.h"
+/* for QDEV_MAX_IRQ */
+#include "hw/sysbus.h"
+
+#define PLATBUS_MAX_IRQ QDEV_MAX_IRQ
+#define PLATBUS_DYNAMIC -1LL
+#define PLATBUS_HOLE (128ULL * 1024 * 1024) /* 128 MB */
+#define PLATBUS_HOLE_PAGES (PLATBUS_HOLE >> 12)
+
+#define TYPE_PLAT_BUS "platbus"
+#define PLAT_BUS(obj) OBJECT_CHECK(PlatBusState, (obj), TYPE_PLAT_BUS)
+
+typedef struct PlatBusState {
+ /*< private >*/
+ BusState parent_obj;
+ qemu_irq irqs[PLATBUS_MAX_IRQ];
+ DECLARE_BITMAP(used_irqs, PLATBUS_MAX_IRQ);
+ DECLARE_BITMAP(used_mem, PLATBUS_HOLE_PAGES);
+ /*< public >*/
+
+ QTAILQ_HEAD(, PlatBusDeviceState) devices;
+ MemoryRegion mem;
+} PlatBusState;
+
+/**
+ * platbus_map_region:
+ * @s: Bus to map the region to
+ * @addr: Pointer to the offset inside the platform bus address range we want
to
+ * map to. Should be PLATBUS_DYNAMIC if the bus is supposed to give us
an
+ * address. Gets written back with the actually mapped address.
+ * @mem: Pointer to a properly initialized MemoryRegion which should get mapped
+ * into the platform bus's address space. Does not get modified.
+ *
+ * Tell the platform bus to map a device's memory region into the platform
bus's
+ * address range.
+ *
+ * Returns: 0 on success. Negative values on error.
+ */
+int platbus_map_region(PlatBusState *s, uint64_t *addr, MemoryRegion *mem);
+
+/**
+ * platbus_map_region:
+ * @s: Bus to map the IRQ to
+ * @irqn: Pointer to the IRQ inside the platform bus IRQ range we want to
+ * map to. Should be PLATBUS_DYNAMIC if the bus is supposed to give us
an
+ * IRQ number. Gets written back with the actually mapped IRQ.
+ * @irq: Pointer to a qemu_irq field. Gets populated with a real qemu_irq when
+ * the mapping gets successfully established.
+ *
+ * Tell the platform bus to map a device's IRQ into the platform bus's IRQ
range.
+ *
+ * Returns: 0 on success. Negative values on error.
+ */
+int platbus_map_irq(PlatBusState *s, uint32_t *irqn, qemu_irq *irq);
+
+/**
+ * platbus_add_irq:
+ * @s: Bus to map the IRQ to
+ * @irqn: IRQ number that gets declared valid
+ *
+ * Tell the platform bus that one of its internal IRQ lines was successfully
+ * populated with a usable qemu_irq object.
+ *
+ * Returns: 0 on success. Negative values on error.
+ */
+void platbus_add_irq(PlatBusState *s, uint32_t irqn);
+
+#endif /* !QEMU_HW_PLATBUS_PLATBUS_H */
--
1.8.1.4
