[PATCH 5.15 172/201] um: virtio_uml: Allow probing from devicetree

Greg Kroah-Hartman
2022-07-27T17:22:50Z

From: Vincent Whitchurch <vincent.whitchurch@axis.com>

[ Upstream commit db0dd9cee82270e032123169ceff659eced5115d ]

Allow the virtio_uml device to be probed from the devicetree so that
sub-devices can be specified using the standard virtio bindings, for
example:

virtio@1 {
compatible = "virtio,uml";
socket-path = "i2c.sock";
virtio-device-id = <0x22>;

i2c-controller {
compatible = "virtio,device22";
#address-cells = <0x01>;
#size-cells = <0x00>;

light-sensor@01 {
compatible = "ti,opt3001";
reg = <0x01>;
};
};
};

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/um/drivers/virtio_uml.c | 50 +++++++++++++++++++++++++++++++++---
1 file changed, 47 insertions(+), 3 deletions(-)

diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index 7755cb4ff9fc..ba562d68dc04 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -21,6 +21,7 @@
* Based on Virtio MMIO driver by Pawel Moll, copyright 2011-2014, ARM Ltd.
*/
#include <linux/module.h>
+#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/virtio.h>
@@ -49,6 +50,7 @@ struct virtio_uml_platform_data {
struct virtio_uml_device {
struct virtio_device vdev;
struct platform_device *pdev;
+ struct virtio_uml_platform_data *pdata;

spinlock_t sock_lock;
int sock, req_fd, irq;
@@ -149,7 +151,7 @@ static int vhost_user_recv(struct virtio_uml_device *vu_dev,
if (rc == -ECONNRESET && vu_dev->registered) {
struct virtio_uml_platform_data *pdata;

- pdata = vu_dev->pdev->dev.platform_data;
+ pdata = vu_dev->pdata;

virtio_break_device(&vu_dev->vdev);
schedule_work(&pdata->conn_broken_wk);
@@ -1115,21 +1117,63 @@ void virtio_uml_set_no_vq_suspend(struct virtio_device *vdev,
no_vq_suspend ? "dis" : "en");
}

+static void vu_of_conn_broken(struct work_struct *wk)
+{
+ /*
+ * We can't remove the device from the devicetree so the only thing we
+ * can do is warn.
+ */
+ WARN_ON(1);
+}
+
/* Platform device */

+static struct virtio_uml_platform_data *
+virtio_uml_create_pdata(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct virtio_uml_platform_data *pdata;
+ int ret;
+
+ if (!np)
+ return ERR_PTR(-EINVAL);
+
+ pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return ERR_PTR(-ENOMEM);
+
+ INIT_WORK(&pdata->conn_broken_wk, vu_of_conn_broken);
+ pdata->pdev = pdev;
+
+ ret = of_property_read_string(np, "socket-path", &pdata->socket_path);
+ if (ret)
+ return ERR_PTR(ret);
+
+ ret = of_property_read_u32(np, "virtio-device-id",
+ &pdata->virtio_device_id);
+ if (ret)
+ return ERR_PTR(ret);
+
+ return pdata;
+}
+
static int virtio_uml_probe(struct platform_device *pdev)
{
struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
struct virtio_uml_device *vu_dev;
int rc;

- if (!pdata)
- return -EINVAL;
+ if (!pdata) {
+ pdata = virtio_uml_create_pdata(pdev);
+ if (IS_ERR(pdata))
+ return PTR_ERR(pdata);
+ }

vu_dev = kzalloc(sizeof(*vu_dev), GFP_KERNEL);
if (!vu_dev)
return -ENOMEM;

+ vu_dev->pdata = pdata;
vu_dev->vdev.dev.parent = &pdev->dev;
vu_dev->vdev.dev.release = virtio_uml_release_dev;
vu_dev->vdev.config = &virtio_uml_config_ops;
--
2.35.1