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 <[email protected]> Reviewed-by: Christoffer Dall <[email protected]> --- 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/libcflat.h | 3 ++ lib/virtio.c | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ lib/virtio.h | 89 ++++++++++++++++++++++++++++++++ 3 files changed, 250 insertions(+) create mode 100644 lib/virtio.c create mode 100644 lib/virtio.h diff --git a/lib/libcflat.h b/lib/libcflat.h index 9f76d6741344d..57bdb92a3e1b4 100644 --- a/lib/libcflat.h +++ b/lib/libcflat.h @@ -56,6 +56,9 @@ extern long atol(const char *ptr); #define ARRAY_SIZE(_a) (sizeof(_a)/sizeof((_a)[0])) #define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER) +#define container_of(ptr, type, member) ({ \ + const typeof( ((type *)0)->member ) *__mptr = (ptr); \ + (type *)( (char *)__mptr - offsetof(type,member) );}) #define NULL ((void *)0UL) diff --git a/lib/virtio.c b/lib/virtio.c new file mode 100644 index 0000000000000..8e48d364bec7e --- /dev/null +++ b/lib/virtio.c @@ -0,0 +1,158 @@ +/* + * Copyright (C) 2014, Red Hat Inc, Andrew Jones <[email protected]> + * + * This work is licensed under the terms of the GNU LGPL, version 2. + */ +#include "libcflat.h" +#include "alloc.h" +#include "devicetree.h" +#include "asm/io.h" +#include "virtio.h" + +enum virtio_hwdesc_type { + VIRTIO_HWDESC_TYPE_DT = 0, /* device tree */ + NR_VIRTIO_HWDESC_TYPES, +}; + +enum virtio_bus_type { + VIRTIO_BUS_TYPE_MMIO = 0, /* virtio-mmio */ + NR_VIRTIO_BUS_TYPES, +}; + +struct virtio_bind_bus { + bool (*hwdesc_probe)(void); + struct virtio_device *(*device_bind)(u32 devid); +}; + +static struct virtio_device *vm_dt_device_bind(u32 devid); + +static struct virtio_bind_bus +virtio_bind_busses[NR_VIRTIO_HWDESC_TYPES][NR_VIRTIO_BUS_TYPES] = { + +[VIRTIO_HWDESC_TYPE_DT] = { + + [VIRTIO_BUS_TYPE_MMIO] = { + .hwdesc_probe = dt_available, + .device_bind = vm_dt_device_bind, + }, +}, +}; + +struct virtio_device *virtio_bind(u32 devid) +{ + struct virtio_bind_bus *bus; + struct virtio_device *dev; + int i, j; + + for (i = 0; i < NR_VIRTIO_HWDESC_TYPES; ++i) { + for (j = 0; j < NR_VIRTIO_BUS_TYPES; ++j) { + + bus = &virtio_bind_busses[i][j]; + + if (!bus->hwdesc_probe()) + continue; + + dev = bus->device_bind(devid); + if (dev) + return dev; + } + } + + return NULL; +} + +/****************************************************** + * virtio-mmio support (config space only) + ******************************************************/ + +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 *vm_dt_device_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; + + 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 = alloc(sizeof(*vm_dev)); + if (!vm_dev) + return NULL; + + vm_dev->base = info.base; + vm_device_init(vm_dev); + + return &vm_dev->vdev; +} diff --git a/lib/virtio.h b/lib/virtio.h new file mode 100644 index 0000000000000..16ebe7e0a7e70 --- /dev/null +++ b/lib/virtio.h @@ -0,0 +1,89 @@ +#ifndef _VIRTIO_H_ +#define _VIRTIO_H_ +/* + * A minimal implementation of virtio for virtio-mmio config space + * access. + * + * Copyright (C) 2014, Red Hat Inc, Andrew Jones <[email protected]> + * + * 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); +}; + +extern struct virtio_device *virtio_bind(u32 devid); + +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); +} + +/****************************************************** + * virtio-mmio + ******************************************************/ + +#define VIRTIO_MMIO_DEVICE_ID 0x008 +#define VIRTIO_MMIO_CONFIG 0x100 + +#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; +}; + +#endif /* _VIRTIO_H_ */ -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
