Re: [PATCH v3 04/18] driver core: platform: Add driver dma ownership management

[Lu Baolu <baolu.lu@linux.intel.com>]

Hi Greg,

On 2021/12/13 8:50, Lu Baolu wrote:
> On 12/10/21 9:23 AM, Lu Baolu wrote:
>> Hi Greg, Jason and Christoph,
>>
>> On 12/9/21 9:20 AM, Lu Baolu wrote:
>>> On 12/7/21 9:16 PM, Jason Gunthorpe wrote:
>>>> On Tue, Dec 07, 2021 at 10:57:25AM +0800, Lu Baolu wrote:
>>>>> On 12/6/21 11:06 PM, Jason Gunthorpe wrote:
>>>>>> On Mon, Dec 06, 2021 at 06:36:27AM -0800, Christoph Hellwig wrote:
>>>>>>> I really hate the amount of boilerplate code that having this in 
>>>>>>> each
>>>>>>> bus type causes.
>>>>>> +1
>>>>>>
>>>>>> I liked the first version of this series better with the code near
>>>>>> really_probe().
>>>>>>
>>>>>> Can we go back to that with some device_configure_dma() wrapper
>>>>>> condtionally called by really_probe as we discussed?
>>
>> [...]
>>
>>>
>>> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
>>> index 68ea1f949daa..68ca5a579eb1 100644
>>> --- a/drivers/base/dd.c
>>> +++ b/drivers/base/dd.c
>>> @@ -538,6 +538,32 @@ static int call_driver_probe(struct device *dev, 
>>> struct device_driver *drv)
>>>          return ret;
>>>   }
>>>
>>> +static int device_dma_configure(struct device *dev, struct 
>>> device_driver *drv)
>>> +{
>>> +       int ret;
>>> +
>>> +       if (!dev->bus->dma_configure)
>>> +               return 0;
>>> +
>>> +       ret = dev->bus->dma_configure(dev);
>>> +       if (ret)
>>> +               return ret;
>>> +
>>> +       if (!drv->suppress_auto_claim_dma_owner)
>>> +               ret = iommu_device_set_dma_owner(dev, 
>>> DMA_OWNER_DMA_API, NULL);
>>> +
>>> +       return ret;
>>> +}
>>> +
>>> +static void device_dma_cleanup(struct device *dev, struct 
>>> device_driver *drv)
>>> +{
>>> +       if (!dev->bus->dma_configure)
>>> +               return;
>>> +
>>> +       if (!drv->suppress_auto_claim_dma_owner)
>>> +               iommu_device_release_dma_owner(dev, DMA_OWNER_DMA_API);
>>> +}
>>> +
>>>   static int really_probe(struct device *dev, struct device_driver *drv)
>>>   {
>>>          bool test_remove = 
>>> IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
>>> @@ -574,11 +600,8 @@ static int really_probe(struct device *dev, 
>>> struct device_driver *drv)
>>>          if (ret)
>>>                  goto pinctrl_bind_failed;
>>>
>>> -       if (dev->bus->dma_configure) {
>>> -               ret = dev->bus->dma_configure(dev);
>>> -               if (ret)
>>> -                       goto probe_failed;
>>> -       }
>>> +       if (device_dma_configure(dev, drv))
>>> +               goto pinctrl_bind_failed;
>>>
>>>          ret = driver_sysfs_add(dev);
>>>          if (ret) {
>>> @@ -660,6 +683,8 @@ static int really_probe(struct device *dev, 
>>> struct device_driver *drv)
>>>          if (dev->bus)
>>>                  
>>> blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
>>>
>>> BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
>>> +
>>> +       device_dma_cleanup(dev, drv);
>>>   pinctrl_bind_failed:
>>>          device_links_no_driver(dev);
>>>          devres_release_all(dev);
>>> @@ -1204,6 +1229,7 @@ static void __device_release_driver(struct 
>>> device *dev, struct device *parent)
>>>                  else if (drv->remove)
>>>                          drv->remove(dev);
>>>
>>> +               device_dma_cleanup(dev, drv);
>>>                  device_links_driver_cleanup(dev);
>>>
>>>                  devres_release_all(dev);
>>> diff --git a/include/linux/device/driver.h 
>>> b/include/linux/device/driver.h
>>> index a498ebcf4993..374a3c2cc10d 100644
>>> --- a/include/linux/device/driver.h
>>> +++ b/include/linux/device/driver.h
>>> @@ -100,6 +100,7 @@ struct device_driver {
>>>          const char              *mod_name;      /* used for built-in 
>>> modules */
>>>
>>>          bool suppress_bind_attrs;       /* disables bind/unbind via 
>>> sysfs */
>>> +       bool suppress_auto_claim_dma_owner;
>>>          enum probe_type probe_type;
>>>
>>>          const struct of_device_id       *of_match_table;
>>
>> Does this work for you? Can I work towards this in the next version?
> 
> A kindly ping ... Is this heading the right direction? I need your
> advice to move ahead. :-)

Can I do it like this? :-)

Best regards,
baolu