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 char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-testing 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 be merged to the char-misc-next branch sometime soon, after it passes testing, and the merge window is open.

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

From 5caf6102e32ead7ed5d21b5309c1a4a7d70e6a9f Mon Sep 17 00:00:00 2001

From: Ulf Hansson ulf.hansson@linaro.org Date: Wed, 25 Mar 2020 12:34:07 +0100 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().

Cc: stable@vger.kernel.org Cc: Russell King linux@armlinux.org.uk Suggested-by: Christoph Hellwig hch@lst.de Tested-by: Ludovic Barre ludovic.barre@st.com Reviewed-by: Linus Walleij linus.walleij@linaro.org Acked-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Ulf Hansson ulf.hansson@linaro.org Link: https://lore.kernel.org/r/20200325113407.26996-3-ulf.hansson@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/amba/bus.c | 2 ++ include/linux/amba/bus.h | 1 + 2 files changed, 3 insertions(+)

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index fe1523664816..5e61783ce92d 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -374,6 +374,8 @@ static int amba_device_try_add(struct amba_device *dev, struct resource *parent) WARN_ON(dev->irq[0] == (unsigned int)-1); WARN_ON(dev->irq[1] == (unsigned int)-1);

+ dev->dev.dma_parms = &dev->dma_parms; + ret = request_resource(parent, &dev->res); if (ret) goto err_out; diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h index 26f0ecf401ea..0bbfd647f5c6 100644 --- a/include/linux/amba/bus.h +++ b/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;