Hi Greg,
(resending because it got bounced off a few lists due a line a copied
with HTML tag..)
On 7/3/23 3:28 PM, Greg KH wrote:
On Tue, Jun 27, 2023 at 10:16:24PM +0200, Umang Jain wrote:
The devices that the vchiq interface registers (bcm2835-audio,
bcm2835-camera) are implemented and exposed by the VC04 firmware.
The device tree describes the VC04 itself with the resources required
to communicate with it through a mailbox interface. However, the
vchiq interface registers these devices as platform devices. This
also means the specific drivers for these devices are getting
registered as platform drivers. This is not correct and a blatant
abuse of platform device/driver.
Add a new bus type, vchiq_bus_type and device type (struct vchiq_device)
which will be used to migrate child devices that the vchiq interfaces
creates/registers from the platform device/driver.
Signed-off-by: Umang Jain <umang.jain@xxxxxxxxxxxxxxxx>
---
drivers/staging/vc04_services/Makefile | 1 +
.../interface/vchiq_arm/vchiq_device.c | 78 +++++++++++++++++++
.../interface/vchiq_arm/vchiq_device.h | 43 ++++++++++
3 files changed, 122 insertions(+)
create mode 100644 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c
create mode 100644 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.h
diff --git a/drivers/staging/vc04_services/Makefile b/drivers/staging/vc04_services/Makefile
index 44794bdf6173..2d071e55e175 100644
--- a/drivers/staging/vc04_services/Makefile
+++ b/drivers/staging/vc04_services/Makefile
@@ -5,6 +5,7 @@ vchiq-objs := \
interface/vchiq_arm/vchiq_core.o \
interface/vchiq_arm/vchiq_arm.o \
interface/vchiq_arm/vchiq_debugfs.o \
+ interface/vchiq_arm/vchiq_device.o \
interface/vchiq_arm/vchiq_connected.o \
ifdef CONFIG_VCHIQ_CDEV
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c
new file mode 100644
index 000000000000..dff312e9735c
--- /dev/null
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * vchiq_device.c - VCHIQ generic device and bus-type
+ *
+ * Copyright (c) 2023 Ideas On Board Oy
+ */
+
+#include <linux/device/bus.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#include "vchiq_device.h"
+
+static int vchiq_bus_type_match(struct device *dev, struct device_driver *drv);
+
+struct bus_type vchiq_bus_type = {
+ .name = "vchiq-bus",
+ .match = vchiq_bus_type_match,
+};
+
+static int vchiq_bus_type_match(struct device *dev, struct device_driver *drv)
+{
+ if (dev->bus == &vchiq_bus_type &&
+ strcmp(dev_name(dev), drv->name) == 0)
+ return 1;
+ return 0;
+}
+
+static void vchiq_device_release(struct device *dev)
+{
+ struct vchiq_device *device;
+
+ device = container_of(dev, struct vchiq_device, dev);
+ kfree(device);
+}
+
+int vchiq_device_register(struct device *parent, const char *name)
+{
+ struct vchiq_device *device = NULL;
No need to set this to NULL.
+ int ret;
+
+ device = kzalloc(sizeof(*device), GFP_KERNEL);
+ if (!device)
+ return -ENOMEM;
+
+ device->dev.init_name = name;
+ device->dev.parent = parent;
+ device->dev.bus = &vchiq_bus_type;
+ device->dev.release = vchiq_device_release;
+
+ ret = device_register(&device->dev);
+ if (ret) {
+ put_device(&device->dev);
+ return -EINVAL;
Why not return the error given to you?
+ }
+
+ return 0;
You create a new device, shouldn't you return it? How is it going to be
looked up again?
So I haven't come across usage of the device other than unregistered
right now. If you look at the platform_device static instances of
bcm2835_camera, bcm2835-audio, they are also just used for unregistering
the devices only.
So for unregistering devices on vchiq_bus - I am using the
bus_for_each_dev(&vchiq_bus_type, NULL, NULL, vchiq_device_unregister);
in patch 3/5.
So basically I can return the instances right now, but there would be no
user of those instances.
+}
+
+int vchiq_device_unregister(struct device *dev, void *data)
You should be passing in a sruct vchiq_device *device here, right?
And why the void pointer you do nothing with?
ack
+{
+ device_unregister(dev);
+ return 0;
+}
No need to export this?
In the previous reviews you mentioned not to export it. The
vchiq_bus_type is internal to the vchiq_driver to register it's child
devices. I don't think any other module will be using this bus directly?
Maybe I'm mistaken?
thanks,
greg k-h
