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

Hi Stefan,

Thank for the testing.

On 1/23/23 5:04 AM, Stefan Wahren wrote:

quoted

Hi Umang,

Am 20.01.23 um 21:10 schrieb Umang Jain:

quoted

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/

  Laurent, any thoughts on this please?