fpga: dfl: fme: add DFL_FPGA_FME_PORT_RELEASE/ASSIGN ioctl support.

In order to support virtualization usage via PCIe SRIOV, this patch
adds two ioctls under FPGA Management Engine (FME) to release and
assign back the port device. In order to safely turn Port from PF
into VF and enable PCIe SRIOV, it requires user to invoke this
PORT_RELEASE ioctl to release port firstly to remove userspace
interfaces, and then configure the PF/VF access register in FME.
After disable SRIOV, it requires user to invoke this PORT_ASSIGN
ioctl to attach the port back to PF.

 Ioctl interfaces:
 * DFL_FPGA_FME_PORT_RELEASE
   Release platform device of given port, it deletes port platform
   device to remove related userspace interfaces on PF. After this
   function, then it's safe to configure PF/VF access mode to VF,
   and enable VFs via SRIOV.

 * DFL_FPGA_FME_PORT_ASSIGN
   Assign platform device of given port back to PF. After configure
   PF/VF access mode to PF, this ioctl adds port platform device
   back to re-enable related userspace interfaces on PF.

Signed-off-by: Zhang Yi Z <yi.z.zhang@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Link: https://lore.kernel.org/r/1564914022-3710-2-git-send-email-hao.wu@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 153 insertions, 12 deletions

diff --git a/drivers/fpga/dfl-fme-main.c b/drivers/fpga/dfl-fme-main.c
index 0be4635583d5..dfea2dee78c3 100644
--- a/drivers/fpga/dfl-fme-main.c
+++ b/drivers/fpga/dfl-fme-main.c
@@ -16,6 +16,7 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/uaccess.h>
 #include <linux/fpga-dfl.h>
 
 #include "dfl.h"
@@ -104,9 +105,50 @@ static void fme_hdr_uinit(struct platform_device *pdev,
 	device_remove_groups(&pdev->dev, fme_hdr_groups);
 }
 
+static long fme_hdr_ioctl_release_port(struct dfl_feature_platform_data *pdata,
+				       unsigned long arg)
+{
+	struct dfl_fpga_cdev *cdev = pdata->dfl_cdev;
+	int port_id;
+
+	if (get_user(port_id, (int __user *)arg))
+		return -EFAULT;
+
+	return dfl_fpga_cdev_release_port(cdev, port_id);
+}
+
+static long fme_hdr_ioctl_assign_port(struct dfl_feature_platform_data *pdata,
+				      unsigned long arg)
+{
+	struct dfl_fpga_cdev *cdev = pdata->dfl_cdev;
+	int port_id;
+
+	if (get_user(port_id, (int __user *)arg))
+		return -EFAULT;
+
+	return dfl_fpga_cdev_assign_port(cdev, port_id);
+}
+
+static long fme_hdr_ioctl(struct platform_device *pdev,
+			  struct dfl_feature *feature,
+			  unsigned int cmd, unsigned long arg)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+
+	switch (cmd) {
+	case DFL_FPGA_FME_PORT_RELEASE:
+		return fme_hdr_ioctl_release_port(pdata, arg);
+	case DFL_FPGA_FME_PORT_ASSIGN:
+		return fme_hdr_ioctl_assign_port(pdata, arg);
+	}
+
+	return -ENODEV;
+}
+
 static const struct dfl_feature_ops fme_hdr_ops = {
 	.init = fme_hdr_init,
 	.uinit = fme_hdr_uinit,
+	.ioctl = fme_hdr_ioctl,
 };
 
 static struct dfl_feature_driver fme_feature_drvs[] = {
diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index 4b66aaa32b5a..70ffe8b4c157 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -231,16 +231,20 @@ EXPORT_SYMBOL_GPL(dfl_fpga_port_ops_del);
  */
 int dfl_fpga_check_port_id(struct platform_device *pdev, void *pport_id)
 {
-	struct dfl_fpga_port_ops *port_ops = dfl_fpga_port_ops_get(pdev);
-	int port_id;
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct dfl_fpga_port_ops *port_ops;
+
+	if (pdata->id != FEATURE_DEV_ID_UNUSED)
+		return pdata->id == *(int *)pport_id;
 
+	port_ops = dfl_fpga_port_ops_get(pdev);
 	if (!port_ops || !port_ops->get_id)
 		return 0;
 
-	port_id = port_ops->get_id(pdev);
+	pdata->id = port_ops->get_id(pdev);
 	dfl_fpga_port_ops_put(port_ops);
 
-	return port_id == *(int *)pport_id;
+	return pdata->id == *(int *)pport_id;
 }
 EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
 
@@ -474,6 +478,7 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
 	pdata->dev = fdev;
 	pdata->num = binfo->feature_num;
 	pdata->dfl_cdev = binfo->cdev;
+	pdata->id = FEATURE_DEV_ID_UNUSED;
 	mutex_init(&pdata->lock);
 	lockdep_set_class_and_name(&pdata->lock, &dfl_pdata_keys[type],
 				   dfl_pdata_key_strings[type]);
@@ -973,25 +978,27 @@ void dfl_fpga_feature_devs_remove(struct dfl_fpga_cdev *cdev)
 {
 	struct dfl_feature_platform_data *pdata, *ptmp;
 
-	remove_feature_devs(cdev);
-
 	mutex_lock(&cdev->lock);
-	if (cdev->fme_dev) {
-		/* the fme should be unregistered. */
-		WARN_ON(device_is_registered(cdev->fme_dev));
+	if (cdev->fme_dev)
 		put_device(cdev->fme_dev);
-	}
 
 	list_for_each_entry_safe(pdata, ptmp, &cdev->port_dev_list, node) {
 		struct platform_device *port_dev = pdata->dev;
 
-		/* the port should be unregistered. */
-		WARN_ON(device_is_registered(&port_dev->dev));
+		/* remove released ports */
+		if (!device_is_registered(&port_dev->dev)) {
+			dfl_id_free(feature_dev_id_type(port_dev),
+				    port_dev->id);
+			platform_device_put(port_dev);
+		}
+
 		list_del(&pdata->node);
 		put_device(&port_dev->dev);
 	}
 	mutex_unlock(&cdev->lock);
 
+	remove_feature_devs(cdev);
+
 	fpga_region_unregister(cdev->region);
 	devm_kfree(cdev->parent, cdev);
 }
@@ -1042,6 +1049,88 @@ static int __init dfl_fpga_init(void)
 	return ret;
 }
 
+/**
+ * dfl_fpga_cdev_release_port - release a port platform device
+ *
+ * @cdev: parent container device.
+ * @port_id: id of the port platform device.
+ *
+ * This function allows user to release a port platform device. This is a
+ * mandatory step before turn a port from PF into VF for SRIOV support.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_cdev_release_port(struct dfl_fpga_cdev *cdev, int port_id)
+{
+	struct platform_device *port_pdev;
+	int ret = -ENODEV;
+
+	mutex_lock(&cdev->lock);
+	port_pdev = __dfl_fpga_cdev_find_port(cdev, &port_id,
+					      dfl_fpga_check_port_id);
+	if (!port_pdev)
+		goto unlock_exit;
+
+	if (!device_is_registered(&port_pdev->dev)) {
+		ret = -EBUSY;
+		goto put_dev_exit;
+	}
+
+	ret = dfl_feature_dev_use_begin(dev_get_platdata(&port_pdev->dev));
+	if (ret)
+		goto put_dev_exit;
+
+	platform_device_del(port_pdev);
+	cdev->released_port_num++;
+put_dev_exit:
+	put_device(&port_pdev->dev);
+unlock_exit:
+	mutex_unlock(&cdev->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_cdev_release_port);
+
+/**
+ * dfl_fpga_cdev_assign_port - assign a port platform device back
+ *
+ * @cdev: parent container device.
+ * @port_id: id of the port platform device.
+ *
+ * This function allows user to assign a port platform device back. This is
+ * a mandatory step after disable SRIOV support.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_cdev_assign_port(struct dfl_fpga_cdev *cdev, int port_id)
+{
+	struct platform_device *port_pdev;
+	int ret = -ENODEV;
+
+	mutex_lock(&cdev->lock);
+	port_pdev = __dfl_fpga_cdev_find_port(cdev, &port_id,
+					      dfl_fpga_check_port_id);
+	if (!port_pdev)
+		goto unlock_exit;
+
+	if (device_is_registered(&port_pdev->dev)) {
+		ret = -EBUSY;
+		goto put_dev_exit;
+	}
+
+	ret = platform_device_add(port_pdev);
+	if (ret)
+		goto put_dev_exit;
+
+	dfl_feature_dev_use_end(dev_get_platdata(&port_pdev->dev));
+	cdev->released_port_num--;
+put_dev_exit:
+	put_device(&port_pdev->dev);
+unlock_exit:
+	mutex_unlock(&cdev->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_cdev_assign_port);
+
 static void __exit dfl_fpga_exit(void)
 {
 	dfl_chardev_uinit();
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index a8b869e9e5b7..6f7855e57869 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -183,6 +183,8 @@ struct dfl_feature {
 
 #define DEV_STATUS_IN_USE	0
 
+#define FEATURE_DEV_ID_UNUSED	(-1)
+
 /**
  * struct dfl_feature_platform_data - platform data for feature devices
  *
@@ -191,6 +193,7 @@ struct dfl_feature {
  * @cdev: cdev of feature dev.
  * @dev: ptr to platform device linked with this platform data.
  * @dfl_cdev: ptr to container device.
+ * @id: id used for this feature device.
  * @disable_count: count for port disable.
  * @num: number for sub features.
  * @dev_status: dev status (e.g. DEV_STATUS_IN_USE).
@@ -203,6 +206,7 @@ struct dfl_feature_platform_data {
 	struct cdev cdev;
 	struct platform_device *dev;
 	struct dfl_fpga_cdev *dfl_cdev;
+	int id;
 	unsigned int disable_count;
 	unsigned long dev_status;
 	void *private;
@@ -373,6 +377,7 @@ void dfl_fpga_enum_info_free(struct dfl_fpga_enum_info *info);
  * @fme_dev: FME feature device under this container device.
  * @lock: mutex lock to protect the port device list.
  * @port_dev_list: list of all port feature devices under this container device.
+ * @released_port_num: released port number under this container device.
  */
 struct dfl_fpga_cdev {
 	struct device *parent;
@@ -380,6 +385,7 @@ struct dfl_fpga_cdev {
 	struct device *fme_dev;
 	struct mutex lock;
 	struct list_head port_dev_list;
+	int released_port_num;
 };
 
 struct dfl_fpga_cdev *
@@ -407,4 +413,8 @@ dfl_fpga_cdev_find_port(struct dfl_fpga_cdev *cdev, void *data,
 
 	return pdev;
 }
+
+int dfl_fpga_cdev_release_port(struct dfl_fpga_cdev *cdev, int port_id);
+int dfl_fpga_cdev_assign_port(struct dfl_fpga_cdev *cdev, int port_id);
+
 #endif /* __FPGA_DFL_H */