[PATCH v2] xen: Stop abusing DT of_dma_configure API

From: Rob Herring
Date: Tue Oct 08 2019 - 15:42:00 EST


As the removed comments say, these aren't DT based devices.
of_dma_configure() is going to stop allowing a NULL DT node and calling
it will no longer work.

The comment is also now out of date as of commit 9ab91e7c5c51 ("arm64:
default to the direct mapping in get_arch_dma_ops"). Direct mapping
is now the default rather than dma_dummy_ops.

According to Stefano and Oleksandr, the only other part needed is
setting the DMA masks and there's no reason to restrict the masks to
32-bits. So set the masks to 64 bits.

Cc: Robin Murphy <robin.murphy@xxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
Cc: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
---
v2:
- Setup dma masks
- Also fix xen_drm_front.c

This can now be applied to the Xen tree independent of the coming
of_dma_configure() changes.

Rob

drivers/gpu/drm/xen/xen_drm_front.c | 12 ++----------
drivers/xen/gntdev.c | 13 ++-----------
2 files changed, 4 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c
index ba1828acd8c9..4be49c1aef51 100644
--- a/drivers/gpu/drm/xen/xen_drm_front.c
+++ b/drivers/gpu/drm/xen/xen_drm_front.c
@@ -718,17 +718,9 @@ static int xen_drv_probe(struct xenbus_device *xb_dev,
struct device *dev = &xb_dev->dev;
int ret;

- /*
- * The device is not spawn from a device tree, so arch_setup_dma_ops
- * is not called, thus leaving the device with dummy DMA ops.
- * This makes the device return error on PRIME buffer import, which
- * is not correct: to fix this call of_dma_configure() with a NULL
- * node to set default DMA ops.
- */
- dev->coherent_dma_mask = DMA_BIT_MASK(32);
- ret = of_dma_configure(dev, NULL, true);
+ ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(64));
if (ret < 0) {
- DRM_ERROR("Cannot setup DMA ops, ret %d", ret);
+ DRM_ERROR("Cannot setup DMA mask, ret %d", ret);
return ret;
}

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index a446a7221e13..81401f386c9c 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -22,6 +22,7 @@

#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt

+#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
@@ -34,9 +35,6 @@
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/refcount.h>
-#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
-#include <linux/of_device.h>
-#endif

#include <xen/xen.h>
#include <xen/grant_table.h>
@@ -625,14 +623,7 @@ static int gntdev_open(struct inode *inode, struct file *flip)
flip->private_data = priv;
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
priv->dma_dev = gntdev_miscdev.this_device;
-
- /*
- * The device is not spawn from a device tree, so arch_setup_dma_ops
- * is not called, thus leaving the device with dummy DMA ops.
- * Fix this by calling of_dma_configure() with a NULL node to set
- * default DMA ops.
- */
- of_dma_configure(priv->dma_dev, NULL, true);
+ dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));
#endif
pr_debug("priv %p\n", priv);

--
2.20.1