amba: Initialize dma_parms for amba devices

It's currently the amba driver's responsibility to initialize the pointer,
dma_parms, for its corresponding struct device. The benefit with this
approach allows us to avoid the initialization and to not waste memory for
the struct device_dma_parameters, as this can be decided on a case by case
basis.

However, it has turned out that this approach is not very practical. Not
only does it lead to open coding, but also to real errors. In principle
callers of dma_set_max_seg_size() doesn't check the error code, but just
assumes it succeeds.

For these reasons, let's do the initialization from the common amba bus at
the device registration point. This also follows the way the PCI devices
are being managed, see pci_device_add().

Suggested-by: Christoph Hellwig <[email protected]>
Cc: Russell King <[email protected]>
Cc: <[email protected]>
Tested-by: Haibo Chen <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/amba/bus.c

@@ -645,6 +645,7 @@ static void amba_device_initialize(struct amba_device *dev, const char *name)
 	dev->dev.release = amba_device_release;
 	dev->dev.bus = &amba_bustype;
 	dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
+	dev->dev.dma_parms = &dev->dma_parms;
 	dev->res.name = dev_name(&dev->dev);
 }
 

include/linux/amba/bus.h

@@ -65,6 +65,7 @@ struct amba_device {
 	struct device		dev;
 	struct resource		res;
 	struct clk		*pclk;
+	struct device_dma_parameters dma_parms;
 	unsigned int		periphid;
 	unsigned int		cid;
 	struct amba_cs_uci_id	uci;