Commit 522c532c authored by Vincent Whitchurch's avatar Vincent Whitchurch Committed by Richard Weinberger
Browse files

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: default avatarVincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 935f8f7a

arch/um/drivers/virt-pci.c

+91 −0
Original line number Diff line number Diff line
@@ -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"))