diff options
author | Vincent Whitchurch <vincent.whitchurch@axis.com> | 2023-01-27 15:30:27 +0100 |
---|---|---|
committer | Richard Weinberger <richard@nod.at> | 2023-02-13 10:14:31 +0100 |
commit | 522c532c4fe730258118fb146577ec9bedf6b807 (patch) | |
tree | c70089e18b237790bdbd045225ec0862ae1c807e /arch/um | |
parent | 935f8f7a0123ffa0a2dd7234713dc2ebeeb08955 (diff) | |
download | linux-522c532c4fe730258118fb146577ec9bedf6b807.tar.gz |
virt-pci: add platform bus support
This driver registers PCI busses, but the underlying virtio protocol
could just as easily be used to provide a platform bus instead. If the
virtio device node in the devicetree indicates that it's compatible with
simple-bus, register platform devices instead of handling it as a PCI
bus.
Only one platform bus is allowed and the logic MMIO region for the
platform bus is placed at an arbitrarily-chosen address away from the
PCI region.
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um')
-rw-r--r-- | arch/um/drivers/virt-pci.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c index 0aa71c08210d..2ba89347053a 100644 --- a/arch/um/drivers/virt-pci.c +++ b/arch/um/drivers/virt-pci.c @@ -8,6 +8,7 @@ #include <linux/virtio.h> #include <linux/virtio_config.h> #include <linux/logic_iomem.h> +#include <linux/of_platform.h> #include <linux/irqdomain.h> #include <linux/virtio_pcidev.h> #include <linux/virtio-uml.h> @@ -39,6 +40,8 @@ struct um_pci_device { unsigned long status; int irq; + + bool platform; }; struct um_pci_device_reg { @@ -48,6 +51,7 @@ struct um_pci_device_reg { static struct pci_host_bridge *bridge; static DEFINE_MUTEX(um_pci_mtx); +static struct um_pci_device *um_pci_platform_device; static struct um_pci_device_reg um_pci_devices[MAX_DEVICES]; static struct fwnode_handle *um_pci_fwnode; static struct irq_domain *um_pci_inner_domain; @@ -481,6 +485,9 @@ static void um_pci_handle_irq_message(struct virtqueue *vq, struct virtio_device *vdev = vq->vdev; struct um_pci_device *dev = vdev->priv; + if (!dev->irq) + return; + /* we should properly chain interrupts, but on ARCH=um we don't care */ switch (msg->op) { @@ -581,6 +588,55 @@ static int um_pci_init_vqs(struct um_pci_device *dev) return 0; } +static void __um_pci_virtio_platform_remove(struct virtio_device *vdev, + struct um_pci_device *dev) +{ + virtio_reset_device(vdev); + vdev->config->del_vqs(vdev); + + mutex_lock(&um_pci_mtx); + um_pci_platform_device = NULL; + mutex_unlock(&um_pci_mtx); + + kfree(dev); +} + +static int um_pci_virtio_platform_probe(struct virtio_device *vdev, + struct um_pci_device *dev) +{ + int ret; + + dev->platform = true; + + mutex_lock(&um_pci_mtx); + + if (um_pci_platform_device) { + mutex_unlock(&um_pci_mtx); + ret = -EBUSY; + goto out_free; + } + + ret = um_pci_init_vqs(dev); + if (ret) { + mutex_unlock(&um_pci_mtx); + goto out_free; + } + + um_pci_platform_device = dev; + + mutex_unlock(&um_pci_mtx); + + ret = of_platform_default_populate(vdev->dev.of_node, NULL, &vdev->dev); + if (ret) + __um_pci_virtio_platform_remove(vdev, dev); + + return ret; + +out_free: + kfree(dev); + return ret; +} + static int um_pci_virtio_probe(struct virtio_device *vdev) { struct um_pci_device *dev; @@ -594,6 +650,9 @@ static int um_pci_virtio_probe(struct virtio_device *vdev) dev->vdev = vdev; vdev->priv = dev; + if (of_device_is_compatible(vdev->dev.of_node, "simple-bus")) + return um_pci_virtio_platform_probe(vdev, dev); + mutex_lock(&um_pci_mtx); for (i = 0; i < MAX_DEVICES; i++) { if (um_pci_devices[i].dev) @@ -643,6 +702,12 @@ static void um_pci_virtio_remove(struct virtio_device *vdev) struct um_pci_device *dev = vdev->priv; int i; + if (dev->platform) { + of_platform_depopulate(&vdev->dev); + __um_pci_virtio_platform_remove(vdev, dev); + return; + } + /* Stop all virtqueues */ virtio_reset_device(vdev); vdev->config->del_vqs(vdev); @@ -880,6 +945,30 @@ void *pci_root_bus_fwnode(struct pci_bus *bus) return um_pci_fwnode; } +static long um_pci_map_platform(unsigned long offset, size_t size, + const struct logic_iomem_ops **ops, + void **priv) +{ + if (!um_pci_platform_device) + return -ENOENT; + + *ops = &um_pci_device_bar_ops; + *priv = &um_pci_platform_device->resptr[0]; + + return 0; +} + +static const struct logic_iomem_region_ops um_pci_platform_ops = { + .map = um_pci_map_platform, +}; + +static struct resource virt_platform_resource = { + .name = "platform", + .start = 0x10000000, + .end = 0x1fffffff, + .flags = IORESOURCE_MEM, +}; + static int __init um_pci_init(void) { int err, i; @@ -888,6 +977,8 @@ static int __init um_pci_init(void) &um_pci_cfgspace_ops)); WARN_ON(logic_iomem_add_region(&virt_iomem_resource, &um_pci_iomem_ops)); + WARN_ON(logic_iomem_add_region(&virt_platform_resource, + &um_pci_platform_ops)); if (WARN(CONFIG_UML_PCI_OVER_VIRTIO_DEVICE_ID < 0, "No virtio device ID configured for PCI - no PCI support\n")) |