[PATCH v7 05/14] add minimal virtio support for devtree virtio-mmio

Andrew Jones
2014-07-16T08:47:59Z

Support the bare minimum of virtio to enable access to the virtio-mmio
config space of a device. Currently this implementation must use a
device tree to find the device.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
---
v7:
- s/alloc/calloc/
- split into virtio.[ch] and virtio-mmio.[ch] [Paolo Bonzini]
- dump virtio_bind_busses table [Paolo Bonzini]
v6:
- switch to using alloc()
- s/vmdev/vm_dev/ to be consistent with kernel naming
- check for virtio magic in vm_dt_match
v5:
- use same virtio struct names as kernel
- no need to alloc a new virtio_config_ops for each virtio device
- use ioremap
v4:
- split from the virtio-testdev patch
- search a table to "discover" that the device must be DT/virtio-mmio,
which doesn't change anything, but looks less hacky than comments
saying the device must be DT/virtio-mmio...
- manage own pool of virtio-mmio pre-allocated device structures in
order to avoid needing access to the heap
---
lib/virtio-mmio.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
lib/virtio-mmio.h | 47 +++++++++++++++++++++++
lib/virtio.c | 13 +++++++
lib/virtio.h | 74 ++++++++++++++++++++++++++++++++++++
4 files changed, 245 insertions(+)
create mode 100644 lib/virtio-mmio.c
create mode 100644 lib/virtio-mmio.h
create mode 100644 lib/virtio.c
create mode 100644 lib/virtio.h

diff --git a/lib/virtio-mmio.c b/lib/virtio-mmio.c
new file mode 100644
index 0000000000000..7331abf128cc5
--- /dev/null
+++ b/lib/virtio-mmio.c
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2014, Red Hat Inc, Andrew Jones <drjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+#include "libcflat.h"
+#include "devicetree.h"
+#include "alloc.h"
+#include "asm/io.h"
+#include "virtio.h"
+#include "virtio-mmio.h"
+
+static void vm_get(struct virtio_device *vdev, unsigned offset,
+ void *buf, unsigned len)
+{
+ struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
+ u8 *p = buf;
+ unsigned i;
+
+ for (i = 0; i < len; ++i)
+ p[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
+}
+
+static void vm_set(struct virtio_device *vdev, unsigned offset,
+ const void *buf, unsigned len)
+{
+ struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
+ const u8 *p = buf;
+ unsigned i;
+
+ for (i = 0; i < len; ++i)
+ writeb(p[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
+}
+
+static const struct virtio_config_ops vm_config_ops = {
+ .get = vm_get,
+ .set = vm_set,
+};
+
+static void vm_device_init(struct virtio_mmio_device *vm_dev)
+{
+ vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
+ vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
+ vm_dev->vdev.config = &vm_config_ops;
+}
+
+/******************************************************
+ * virtio-mmio device tree support
+ ******************************************************/
+
+struct vm_dt_info {
+ u32 devid;
+ void *base;
+};
+
+static int vm_dt_match(const struct dt_device *dev, int fdtnode)
+{
+ struct vm_dt_info *info = (struct vm_dt_info *)dev->info;
+ struct dt_pbus_reg base;
+ u32 magic;
+
+ dt_device_bind_node((struct dt_device *)dev, fdtnode);
+
+ assert(dt_pbus_get_base(dev, &base) == 0);
+ info->base = ioremap(base.addr, base.size);
+
+ magic = readl(info->base + VIRTIO_MMIO_MAGIC_VALUE);
+ if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24))
+ return false;
+
+ return readl(info->base + VIRTIO_MMIO_DEVICE_ID) == info->devid;
+}
+
+static struct virtio_device *virtio_mmio_dt_bind(u32 devid)
+{
+ struct virtio_mmio_device *vm_dev;
+ struct dt_device dt_dev;
+ struct dt_bus dt_bus;
+ struct vm_dt_info info;
+ int node;
+
+ if (!dt_available())
+ return NULL;
+
+ dt_bus_init_defaults(&dt_bus);
+ dt_bus.match = vm_dt_match;
+
+ info.devid = devid;
+
+ dt_device_init(&dt_dev, &dt_bus, &info);
+
+ node = dt_device_find_compatible(&dt_dev, "virtio,mmio");
+ assert(node >= 0 || node == -FDT_ERR_NOTFOUND);
+
+ if (node == -FDT_ERR_NOTFOUND)
+ return NULL;
+
+ vm_dev = calloc(1, sizeof(*vm_dev));
+ if (!vm_dev)
+ return NULL;
+
+ vm_dev->base = info.base;
+ vm_device_init(vm_dev);
+
+ return &vm_dev->vdev;
+}
+
+struct virtio_device *virtio_mmio_bind(u32 devid)
+{
+ return virtio_mmio_dt_bind(devid);
+}
diff --git a/lib/virtio-mmio.h b/lib/virtio-mmio.h
new file mode 100644
index 0000000000000..7cd610428b486
--- /dev/null
+++ b/lib/virtio-mmio.h
@@ -0,0 +1,47 @@
+#ifndef _VIRTIO_MMIO_H_
+#define _VIRTIO_MMIO_H_
+/*
+ * A minimal implementation of virtio-mmio. Adapted from the Linux Kernel.
+ *
+ * Copyright (C) 2014, Red Hat Inc, Andrew Jones <drjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+#include "libcflat.h"
+#include "virtio.h"
+
+#define VIRTIO_MMIO_MAGIC_VALUE 0x000
+#define VIRTIO_MMIO_VERSION 0x004
+#define VIRTIO_MMIO_DEVICE_ID 0x008
+#define VIRTIO_MMIO_VENDOR_ID 0x00c
+#define VIRTIO_MMIO_HOST_FEATURES 0x010
+#define VIRTIO_MMIO_HOST_FEATURES_SEL 0x014
+#define VIRTIO_MMIO_GUEST_FEATURES 0x020
+#define VIRTIO_MMIO_GUEST_FEATURES_SEL 0x024
+#define VIRTIO_MMIO_GUEST_PAGE_SIZE 0x028
+#define VIRTIO_MMIO_QUEUE_SEL 0x030
+#define VIRTIO_MMIO_QUEUE_NUM_MAX 0x034
+#define VIRTIO_MMIO_QUEUE_NUM 0x038
+#define VIRTIO_MMIO_QUEUE_ALIGN 0x03c
+#define VIRTIO_MMIO_QUEUE_PFN 0x040
+#define VIRTIO_MMIO_QUEUE_NOTIFY 0x050
+#define VIRTIO_MMIO_INTERRUPT_STATUS 0x060
+#define VIRTIO_MMIO_INTERRUPT_ACK 0x064
+#define VIRTIO_MMIO_STATUS 0x070
+#define VIRTIO_MMIO_CONFIG 0x100
+
+#define VIRTIO_MMIO_INT_VRING (1 << 0)
+#define VIRTIO_MMIO_INT_CONFIG (1 << 1)
+
+
+#define to_virtio_mmio_device(vdev_ptr) \
+ container_of(vdev_ptr, struct virtio_mmio_device, vdev)
+
+struct virtio_mmio_device {
+ struct virtio_device vdev;
+ void *base;
+};
+
+extern struct virtio_device *virtio_mmio_bind(u32 devid);
+
+#endif /* _VIRTIO_MMIO_H_ */
diff --git a/lib/virtio.c b/lib/virtio.c
new file mode 100644
index 0000000000000..b9c403cc71e05
--- /dev/null
+++ b/lib/virtio.c
@@ -0,0 +1,13 @@
+/*
+ * Copyright (C) 2014, Red Hat Inc, Andrew Jones <drjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+#include "libcflat.h"
+#include "virtio.h"
+#include "virtio-mmio.h"
+
+struct virtio_device *virtio_bind(u32 devid)
+{
+ return virtio_mmio_bind(devid);
+}
diff --git a/lib/virtio.h b/lib/virtio.h
new file mode 100644
index 0000000000000..5941fa40a8655
--- /dev/null
+++ b/lib/virtio.h
@@ -0,0 +1,74 @@
+#ifndef _VIRTIO_H_
+#define _VIRTIO_H_
+/*
+ * A minimal implementation of virtio.
+ * Structures adapted from the Linux Kernel.
+ *
+ * Copyright (C) 2014, Red Hat Inc, Andrew Jones <drjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+#include "libcflat.h"
+
+struct virtio_device_id {
+ u32 device;
+ u32 vendor;
+};
+
+struct virtio_device {
+ struct virtio_device_id id;
+ const struct virtio_config_ops *config;
+};
+
+struct virtio_config_ops {
+ void (*get)(struct virtio_device *vdev, unsigned offset,
+ void *buf, unsigned len);
+ void (*set)(struct virtio_device *vdev, unsigned offset,
+ const void *buf, unsigned len);
+};
+
+static inline u8
+virtio_config_readb(struct virtio_device *vdev, unsigned offset)
+{
+ u8 val;
+ vdev->config->get(vdev, offset, &val, 1);
+ return val;
+}
+
+static inline u16
+virtio_config_readw(struct virtio_device *vdev, unsigned offset)
+{
+ u16 val;
+ vdev->config->get(vdev, offset, &val, 2);
+ return val;
+}
+
+static inline u32
+virtio_config_readl(struct virtio_device *vdev, unsigned offset)
+{
+ u32 val;
+ vdev->config->get(vdev, offset, &val, 4);
+ return val;
+}
+
+static inline void
+virtio_config_writeb(struct virtio_device *vdev, unsigned offset, u8 val)
+{
+ vdev->config->set(vdev, offset, &val, 1);
+}
+
+static inline void
+virtio_config_writew(struct virtio_device *vdev, unsigned offset, u16 val)
+{
+ vdev->config->set(vdev, offset, &val, 2);
+}
+
+static inline void
+virtio_config_writel(struct virtio_device *vdev, unsigned offset, u32 val)
+{
+ vdev->config->set(vdev, offset, &val, 4);
+}
+
+extern struct virtio_device *virtio_bind(u32 devid);
+
+#endif /* _VIRTIO_H_ */
--
1.9.3