dmaengine: idxd: Binding and unbinding IDXD device and driver

Add idxd_bind() and idxd_unbind() helpers to bind and unbind the IDXD
device and driver.

These helpers will be called during Function Level Reset (FLR) processing.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20241122233028.2762809-3-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: Fenghua Yu

drivers/dma/idxd/init.c

@@ -725,6 +725,39 @@ static void idxd_cleanup(struct idxd_device *idxd)
 		idxd_disable_sva(idxd->pdev);
 }
 
+/*
+ * Attach IDXD device to IDXD driver.
+ */
+static int idxd_bind(struct device_driver *drv, const char *buf)
+{
+	const struct bus_type *bus = drv->bus;
+	struct device *dev;
+	int err = -ENODEV;
+
+	dev = bus_find_device_by_name(bus, NULL, buf);
+	if (dev)
+		err = device_driver_attach(drv, dev);
+
+	put_device(dev);
+
+	return err;
+}
+
+/*
+ * Detach IDXD device from driver.
+ */
+static void idxd_unbind(struct device_driver *drv, const char *buf)
+{
+	const struct bus_type *bus = drv->bus;
+	struct device *dev;
+
+	dev = bus_find_device_by_name(bus, NULL, buf);
+	if (dev && dev->driver == drv)
+		device_release_driver(dev);
+
+	put_device(dev);
+}
+
 /*
  * Probe idxd PCI device.
  * If idxd is not given, need to allocate idxd and set up its data.