vfio: platform: introduce vfio-platform-base module

To prepare for vfio platform reset rework let's build
vfio_platform_common.c and vfio_platform_irq.c in a separate
module from vfio-platform and vfio-amba. This makes possible
to have separate module inits and works around a race between
platform driver init and vfio reset module init: that way we
make sure symbols exported by base are available when vfio-platform
driver gets probed.

The open/release being implemented in the base module, the ref
count is applied to the parent module instead.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

5 files changed, 18 insertions, 4 deletions

diff --git a/drivers/vfio/platform/Makefile b/drivers/vfio/platform/Makefile
index 9ce8afe28450..41a6224f5e6b 100644
--- a/drivers/vfio/platform/Makefile
+++ b/drivers/vfio/platform/Makefile
@@ -1,10 +1,12 @@
-
-vfio-platform-y := vfio_platform.o vfio_platform_common.o vfio_platform_irq.o
+vfio-platform-base-y := vfio_platform_common.o vfio_platform_irq.o
+vfio-platform-y := vfio_platform.o
 
 obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform.o
+obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform-base.o
 obj-$(CONFIG_VFIO_PLATFORM) += reset/
 
 vfio-amba-y := vfio_amba.o
 
 obj-$(CONFIG_VFIO_AMBA) += vfio-amba.o
+obj-$(CONFIG_VFIO_AMBA) += vfio-platform-base.o
 obj-$(CONFIG_VFIO_AMBA) += reset/
diff --git a/drivers/vfio/platform/vfio_amba.c b/drivers/vfio/platform/vfio_amba.c
index ff0331f72526..a66479bd0edf 100644
--- a/drivers/vfio/platform/vfio_amba.c
+++ b/drivers/vfio/platform/vfio_amba.c
@@ -67,6 +67,7 @@ static int vfio_amba_probe(struct amba_device *adev, const struct amba_id *id)
         vdev->flags = VFIO_DEVICE_FLAGS_AMBA;
         vdev->get_resource = get_amba_resource;
         vdev->get_irq = get_amba_irq;
+        vdev->parent_module = THIS_MODULE;
 
         ret = vfio_platform_probe_common(vdev, &adev->dev);
         if (ret) {
diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c
index cef645c83996..f1625dcfbb23 100644
--- a/drivers/vfio/platform/vfio_platform.c
+++ b/drivers/vfio/platform/vfio_platform.c
@@ -65,6 +65,7 @@ static int vfio_platform_probe(struct platform_device *pdev)
         vdev->flags = VFIO_DEVICE_FLAGS_PLATFORM;
         vdev->get_resource = get_platform_resource;
         vdev->get_irq = get_platform_irq;
+        vdev->parent_module = THIS_MODULE;
 
         ret = vfio_platform_probe_common(vdev, &pdev->dev);
         if (ret)
diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 8c216de883e3..7f69b852c7e2 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -23,6 +23,10 @@
 
 #include "vfio_platform_private.h"
 
+#define DRIVER_VERSION  "0.10"
+#define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"
+#define DRIVER_DESC     "VFIO platform base module"
+
 static DEFINE_MUTEX(driver_lock);
 
 static const struct vfio_platform_reset_combo reset_lookup_table[] = {
@@ -146,7 +150,7 @@ static void vfio_platform_release(void *device_data)
 
         mutex_unlock(&driver_lock);
 
-        module_put(THIS_MODULE);
+        module_put(vdev->parent_module);
 }
 
 static int vfio_platform_open(void *device_data)
@@ -154,7 +158,7 @@ static int vfio_platform_open(void *device_data)
         struct vfio_platform_device *vdev = device_data;
         int ret;
 
-        if (!try_module_get(THIS_MODULE))
+        if (!try_module_get(vdev->parent_module))
                 return -ENODEV;
 
         mutex_lock(&driver_lock);
@@ -573,3 +577,8 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
         return vdev;
 }
 EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 1c9b3d59543c..71286903fb49 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -56,6 +56,7 @@ struct vfio_platform_device {
         u32                             num_irqs;
         int                             refcnt;
         struct mutex                    igate;
+        struct module                   *parent_module;
 
         /*
          * These fields should be filled by the bus specific binder