Messages in this thread | | | Date | Mon, 11 Sep 2023 22:22:43 +0200 | Subject | Re: [PATCH v10 1/5] staging: vc04_services: vchiq_arm: Add new bus type and device type | From | Stefan Wahren <> |
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Hi Umang,
Am 11.09.23 um 16:07 schrieb Umang Jain: > 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@ideasonboard.com> > --- > drivers/staging/vc04_services/Makefile | 1 + > .../interface/vchiq_arm/vchiq_device.c | 111 ++++++++++++++++++ > .../interface/vchiq_arm/vchiq_device.h | 54 +++++++++ > 3 files changed, 166 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..aad55c461905 > --- /dev/null > +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c > @@ -0,0 +1,111 @@ > +// 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/dma-mapping.h> > +#include <linux/of_device.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) > +{ > + if (dev->bus == &vchiq_bus_type && > + strcmp(dev_name(dev), drv->name) == 0) > + return 1; > + > + return 0; > +} > + > +static int vchiq_bus_uevent(const struct device *dev, struct kobj_uevent_env *env) > +{ > + const struct vchiq_device *device = container_of_const(dev, struct vchiq_device, dev); > + > + return add_uevent_var(env, "MODALIAS=%s", dev_name(&device->dev)); > +} > + > +static int vchiq_bus_probe(struct device *dev) > +{ > + struct vchiq_device *device = to_vchiq_device(dev); > + struct vchiq_driver *driver = to_vchiq_driver(dev->driver); > + int ret; > + > + ret = driver->probe(device); > + if (ret == 0) > + return 0; > + > + return ret; > +} > + > +struct bus_type vchiq_bus_type = { > + .name = "vchiq-bus", > + .match = vchiq_bus_type_match, > + .uevent = vchiq_bus_uevent, > + .probe = vchiq_bus_probe, > +}; > + > +static void vchiq_device_release(struct device *dev) > +{ > + struct vchiq_device *device = to_vchiq_device(dev); > + > + kfree(device); > +} > + > +struct vchiq_device * > +vchiq_device_register(struct device *parent, const char *name) > +{ > + struct vchiq_device *device; > + int ret; > + > + device = kzalloc(sizeof(*device), GFP_KERNEL); > + if (!device) { > + dev_err(parent, "Cannot register %s: Insufficient memory\n", > + name); > + return NULL; > + } > + > + device->dev.init_name = name; > + device->dev.parent = parent; > + device->dev.bus = &vchiq_bus_type; > + device->dev.release = vchiq_device_release; > + > + of_dma_configure(&device->dev, parent->of_node, true); > + ret = dma_set_mask_and_coherent(&device->dev, DMA_BIT_MASK(32)); > + if (ret) { > + dev_err(&device->dev, "32-bit DMA enable failed\n"); > + return NULL; > + }
Unfortunately the call of of_dma_configure() generates warnings likes this (Raspberry Pi 3A+ with multi_v7_defconfig + VCHIQ):
[ 9.206802] vchiq-bus bcm2835-audio: DMA mask not set [ 9.206892] vchiq-bus bcm2835-camera: DMA mask not set
In the old platform driver code we had something like
pdevinfo.dma_mask = DMA_BIT_MASK(32);
So there is still something missing for our new bus driver.
> + > + ret = device_register(&device->dev); > + if (ret) { > + dev_err(parent, "Cannot register %s: %d\n", name, ret); > + put_device(&device->dev); > + return NULL; > + } > + > + return device; > +} > + > +void vchiq_device_unregister(struct vchiq_device *vchiq_dev) > +{ > + device_unregister(&vchiq_dev->dev); > +} > + > +int vchiq_driver_register(struct vchiq_driver *vchiq_drv) > +{ > + vchiq_drv->driver.bus = &vchiq_bus_type; > + > + return driver_register(&vchiq_drv->driver); > +} > +EXPORT_SYMBOL_GPL(vchiq_driver_register); > + > +void vchiq_driver_unregister(struct vchiq_driver *vchiq_drv) > +{ > + driver_unregister(&vchiq_drv->driver); > +} > +EXPORT_SYMBOL_GPL(vchiq_driver_unregister); > diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.h > new file mode 100644 > index 000000000000..7eaaf9a91cda > --- /dev/null > +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.h > @@ -0,0 +1,54 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Copyright (c) 2023 Ideas On Board Oy > + */ > + > +#ifndef _VCHIQ_DEVICE_H > +#define _VCHIQ_DEVICE_H > + > +#include <linux/device.h> > + > +struct vchiq_device { > + struct device dev; > +}; > + > +struct vchiq_driver { > + int (*probe)(struct vchiq_device *device); > + void (*remove)(struct vchiq_device *device); > + int (*resume)(struct vchiq_device *device); > + int (*suspend)(struct vchiq_device *device, > + pm_message_t state); > + struct device_driver driver; > +}; > + > +static inline struct vchiq_device *to_vchiq_device(struct device *d) > +{ > + return container_of(d, struct vchiq_device, dev); > +} > + > +static inline struct vchiq_driver *to_vchiq_driver(struct device_driver *d) > +{ > + return container_of(d, struct vchiq_driver, driver); > +} > + > +extern struct bus_type vchiq_bus_type; > + > +struct vchiq_device * > +vchiq_device_register(struct device *parent, const char *name); > +void vchiq_device_unregister(struct vchiq_device *dev); > + > +int vchiq_driver_register(struct vchiq_driver *vchiq_drv); > +void vchiq_driver_unregister(struct vchiq_driver *vchiq_drv); > + > +/** > + * module_vchiq_driver() - Helper macro for registering a vchiq driver > + * @__vchiq_driver: vchiq driver struct > + * > + * Helper macro for vchiq drivers which do not do anything special in > + * module init/exit. This eliminates a lot of boilerplate. Each module may only > + * use this macro once, and calling it replaces module_init() and module_exit() > + */ > +#define module_vchiq_driver(__vchiq_driver) \ > + module_driver(__vchiq_driver, vchiq_driver_register, vchiq_driver_unregister) > + > +#endif /* _VCHIQ_DEVICE_H */
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