Re: [PATCH v9 0/5] staging: vc04_services: vchiq: Register devices with a custom bus_type

From: Umang Jain
Date: Thu Jul 20 2023 - 08:08:43 EST


Hi Stefan ,


On 7/19/23 11:05 PM, Stefan Wahren wrote:
Hi Umang,

Am 19.07.23 um 18:54 schrieb Umang Jain:
Hi,

One comment,

On 7/19/23 10:14 PM, Umang Jain wrote:
The patch series added a new bus type vchiq_bus_type and registers
child devices in order to move them away from using platform
device/driver.

Patch 1/5 and 2/5 adds a new bus_type and registers them to vchiq
interface

Patch 3/5 and 4/5 moves the bcm2835-camera and bcm2835-audio
to the new bus respectively

Patch 5/5 removes a platform registeration helper which is no
longer required.

Changes in v9:
- Fix module autoloading

While the autoloading of bcm2835-audio, bcm2835-camera is fixed as part of this series, there is one WARN coming in when bcm2835-audio is loaded regarding dma_alloc_attr

dmesg output: https://paste.debian.net/plain/1286359

is it possible that after your patch series no DMA mask like DMA_BIT_MASK(32) is provided?

I am trying to set DMA_BIT_MASK(32) via  dma_set_mask_and_coherent() but it fails with -EIO


I am investigating further...
- Implement bus_type's probe() callback to load drivers
- Implement bus_type's uevent() to make sure appropriate drivers are
   loaded when device are registed from vchiq.

Changes in v8:
- Drop dual licensing. Instead use GPL-2.0 only for patch 1/5

Changes in v7:
(5 out of 6 patches from v6 merged)
- Split the main patch (6/6) as requested.
- Use struct vchiq_device * instead of struct device * in
   all bus functions.
- Drop additional name attribute displayed in sysfs (redundant info)
- Document vchiq_interface doesn't enumerate device discovery
- remove EXPORT_SYMBOL_GPL(vchiq_bus_type)

Changes in v6:
- Split struct device and struct driver wrappers in vchiq_device.[ch]
- Move vchiq_bus_type definition to vchiq_device.[ch] as well
- return error on bus_register() failure
- drop dma_set_mask_and_coherent
- trivial variable name change

Changes in v5:
- Fixup missing "staging: " in commits' subject line
- No code changes from v4

Changes in v4:
- Introduce patches to drop include directives from Makefile

Changes in v3:
- Rework entirely to replace platform devices/driver model

-v2:
https://lore.kernel.org/all/20221222191500.515795-1-umang.jain@xxxxxxxxxxxxxxxx/

-v1:
https://lore.kernel.org/all/20221220084404.19280-1-umang.jain@xxxxxxxxxxxxxxxx/

Umang Jain (5):
   staging: vc04_services: vchiq_arm: Add new bus type and device type
   staging: vc04_services: vchiq_arm: Register vchiq_bus_type
   staging: bcm2835-camera: Register bcm2835-camera with vchiq_bus_type
   staging: bcm2835-audio: Register bcm2835-audio with vchiq_bus_type
   staging: vc04_services: vchiq_arm: Remove vchiq_register_child()

  drivers/staging/vc04_services/Makefile        |   1 +
  .../vc04_services/bcm2835-audio/bcm2835.c     |  20 ++--
  .../bcm2835-camera/bcm2835-camera.c           |  17 +--
  .../interface/vchiq_arm/vchiq_arm.c           |  48 ++++-----
  .../interface/vchiq_arm/vchiq_device.c        | 102 ++++++++++++++++++
  .../interface/vchiq_arm/vchiq_device.h        |  54 ++++++++++
  6 files changed, 196 insertions(+), 46 deletions(-)
  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