patch "amba: Initialize dma_parms for amba devices" added to driver-core-linus

This is a note to let you know that I've just added the patch titled

amba: Initialize dma_parms for amba devices

to my driver-core git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From f458488425f1cc9a396aa1d09bb00c48783936da Mon Sep 17 00:00:00 2001
From: Ulf Hansson <[email protected]>
Date: Wed, 22 Apr 2020 12:10:13 +0200
Subject: 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().

---
 drivers/amba/bus.c       | 1 +
 include/linux/amba/bus.h | 1 +
 2 files changed, 2 insertions(+)

index fe1523664816..8558b629880b 100644
@@ -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);
 }
 

index 26f0ecf401ea..0bbfd647f5c6 100644
@@ -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;

2.26.2