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authorVincent Whitchurch <vincent.whitchurch@axis.com>2023-01-27 15:30:27 +0100
committerRichard Weinberger <richard@nod.at>2023-02-13 10:14:31 +0100
commit522c532c4fe730258118fb146577ec9bedf6b807 (patch)
treec70089e18b237790bdbd045225ec0862ae1c807e /arch/um
parent935f8f7a0123ffa0a2dd7234713dc2ebeeb08955 (diff)
downloadlinux-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.c91
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"))