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

Lu Baolu
2021-12-07T02:57:44Z

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?
>

Are you talking about below change?

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 68ea1f949daa..368f9e530515 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -577,7 +577,13 @@ static int really_probe(struct device *dev, struct
device_driver *drv)
if (dev->bus->dma_configure) {
ret = dev->bus->dma_configure(dev);
if (ret)
- goto probe_failed;
+ goto pinctrl_bind_failed;
+
+ if (!drv->no_kernel_dma) {
+ ret = iommu_device_set_dma_owner(dev, DMA_OWNER_DMA_API, NULL);
+ if (ret)
+ goto pinctrl_bind_failed;
+ }
}

ret = driver_sysfs_add(dev);
@@ -660,6 +666,9 @@ 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);
+
+ if (dev->bus->dma_configure && !drv->no_kernel_dma)
+ iommu_device_release_dma_owner(dev, DMA_OWNER_DMA_API);
pinctrl_bind_failed:
device_links_no_driver(dev);
devres_release_all(dev);
@@ -1204,6 +1213,9 @@ static void __device_release_driver(struct device
*dev, struct device *parent)
else if (drv->remove)
drv->remove(dev);

+ if (dev->bus->dma_configure && !drv->no_kernel_dma)
+ iommu_device_release_dma_owner(dev, DMA_OWNER_DMA_API);
+
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..2cf7b757b28e 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 no_kernel_dma;
enum probe_type probe_type;

const struct of_device_id *of_match_table;

Best regards,
baolu