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

Stefan Wahren
2023-01-23T17:28:59Z

Hi Umang,

Am 23.01.23 um 08:48 schrieb Umang Jain:
> 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);
Yes, this patch fixes the errors above. But i noticed that the series
also break autoprobing of bcm2835-audio and bcm2835-camera.
>
> 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/
>
>  Laurent, any thoughts on this please?
>
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