dma_set_mask_and_coherent() will never return failure when mask >= 32bit.
So needn't fall back to set dma_set_mask_and_coherent(32).
Even if dma_set_mask_and_coherent(48) failure,
dma_set_mask_and_coherent(32) will be failure according to the same reason.
The function dma_set_mask_and_coherent() defines the device DMA access
address width. If it's capable of accessing 48 bits, it inherently supports
32-bit space as well.
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
Notes:
Ref: https://lore.kernel.org/linux-pci/20240328154827.809286-1-Frank.Li@xxxxxxx/T/#u
for document change patch. DMA document sample code is miss leading.
drivers/misc/pci_endpoint_test.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c
index c38a6083f0a73..56ac6969a8f59 100644
--- a/drivers/misc/pci_endpoint_test.c
+++ b/drivers/misc/pci_endpoint_test.c
@@ -824,11 +824,7 @@ static int pci_endpoint_test_probe(struct pci_dev *pdev,
init_completion(&test->irq_raised);
mutex_init(&test->mutex);
- if ((dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(48)) != 0) &&
- dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)) != 0) {
- dev_err(dev, "Cannot set DMA mask\n");
- return -EINVAL;
- }
+ dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(48));
err = pci_enable_device(pdev);
if (err) {
--
2.34.1
