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

Lu Baolu
2021-12-10T01:23:39Z

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,
> NULL);
> +}
> +
>  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?

Best regards,
baolu