Re: [PATCH v6 0/6] staging: vc04_services: vchiq: Register devices with a custom bus_type

[Stefan Wahren <stefan.wahren@xxxxxxxx>]

Hi Phil,

Am 23.01.23 um 09:58 schrieb Laurent Pinchart:
> On Mon, Jan 23, 2023 at 01:18:30PM +0530, Umang Jain wrote:
> > Hi Stefan,
> >
> > Thank for the testing.
> >
> > On 1/23/23 5:04 AM, Stefan Wahren wrote:
> > > Hi Umang,
> > >
> > > Am 20.01.23 um 21:10 schrieb Umang Jain:
> > > > This series just introduces five extra patches for dropping include
> > > > directives from Makefiles (suggested by Greg KH) and rebased.
> > > >
> > > > The main patch (6/6) removes platform device/driver abuse and moves
> > > > things to standard device/driver model using a custom_bus. Specific
> > > > details are elaborated in the commit message.
> > > >
> > > > The patch series is based on top of d514392f17fd (tag: next-20230120)
> > > > of linux-next.
> > > applied this series on top of linux-next and build it with
> > > arm/multi_v7_defconfig plus the following:
> > >
> > > CONFIG_BCM_VIDEOCORE=y
> > > CONFIG_BCM2835_VCHIQ=m
> > > CONFIG_VCHIQ_CDEV=y
> > > CONFIG_SND_BCM2835=m
> > > CONFIG_VIDEO_BCM2835=m
> > > CONFIG_BCM2835_VCHIQ_MMAL=m
> > >
> > > and the devices doesn't register on Raspberry Pi 3 B Plus:
> > >
> > > [   25.523337] vchiq: module is from the staging directory, the quality is unknown, you have been warned.
> > > [   25.541647] bcm2835_vchiq 3f00b840.mailbox: Failed to register bcm2835_audio vchiq device
> > > [   25.553692] bcm2835_vchiq 3f00b840.mailbox: Failed to register bcm2835-camera vchiq device
> > I was able to reproduce and it seems the issue here is the change
> > mentioned in the cover
> >
> > - drop dma_set_mask_and_coherent
> >
> > in V6.
> >
> > (I usually test patches on RPi 4B with vcsm-cma and bcm2835-isp applied
> > so my branch has the DMA hunk included while I was testing V6)
> >
> > Below is the hunk which should resolve the issue.
> >
> > --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c
> > +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c
> > @@ -6,6 +6,7 @@
> >     */
> >
> >    #include <linux/device/bus.h>
> > +#include <linux/dma-mapping.h>
> >    #include <linux/slab.h>
> >    #include <linux/string.h>
> >
> > @@ -72,6 +73,12 @@ int vchiq_device_register(struct device *parent,
> > const char *name)
> >           device->dev.type = &vchiq_device_type;
> >           device->dev.release = vchiq_device_release;
> >
> > +       ret = dma_set_mask_and_coherent(&device->dev, DMA_BIT_MASK(32));
> > +       if (ret < 0) {
> > +               vchiq_device_release(&device->dev);
> > +               return ret;
> > +       }
> > +
> >           ret = device_register(&device->dev);
> >           if (ret) {
> >                   put_device(&device->dev);
> >
> > It seems we need to include the dma_set_mask_and_coherent() even if
> > bcm2835-audio, bcm2835-camera device doesn't do DMA? I need to look into
> > why is that/

Do you have an answer for this?

Thanks

> >    Laurent, any thoughts on this please?
> Nothing that immediately springs to my mind. Can you investigate ?