char: xillybus: Eliminate redundant wrappers to DMA related calls

The driver was originally written with the assumption that a different
API must be used for DMA-related functions if the device is PCIe based
or if not. Since Xillybus' driver supports devices on a PCIe bus (with
xillybus_pcie) as well as connected directly to the processor (with
xillybus_of), it originally used wrapper functions that ensure that
a different API is used for each.

This patch eliminates the said wrapper functions, as all use the same
dma_* API now. This is most notable by the code deleted in xillybus_pcie.c
and xillybus_of.c.

It also eliminates the OF driver's check for a "dma-coherent" attribute
in the device's OF entry, since this is taken care of by the kernel's
implementation of dma_sync_single_for_*().

There is however still need for one wrapper function, which is merged
from xillybus_pcie.c and xillybus_of.c into xillybus_core.c: The call to
dma_map_single() is wrapped by a function that uses the Managed Device
(devres) framework, in the absence of a relevant function in the current
kernel's API.

Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Eli Billauer <eli.billauer@gmail.com>
Link: https://lore.kernel.org/r/20210929094442.46383-1-eli.billauer@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 21 deletions

diff --git a/drivers/char/xillybus/xillybus.h b/drivers/char/xillybus/xillybus.h
index afce5bb4d127..51de7cbc579e 100644
--- a/drivers/char/xillybus/xillybus.h
+++ b/drivers/char/xillybus/xillybus.h
@@ -88,7 +88,7 @@ struct xilly_channel {
 
 struct xilly_endpoint {
 	struct device *dev;
-	struct xilly_endpoint_hardware *ephw;
+	struct module *owner;
 
 	int dma_using_dac; /* =1 if 64-bit DMA is used, =0 otherwise. */
 	__iomem void *registers;
@@ -108,23 +108,6 @@ struct xilly_endpoint {
 	unsigned int msg_buf_size;
 };
 
-struct xilly_endpoint_hardware {
-	struct module *owner;
-	void (*hw_sync_sgl_for_cpu)(struct xilly_endpoint *,
-				    dma_addr_t,
-				    size_t,
-				    int);
-	void (*hw_sync_sgl_for_device)(struct xilly_endpoint *,
-				       dma_addr_t,
-				       size_t,
-				       int);
-	int (*map_single)(struct xilly_endpoint *,
-			  void *,
-			  size_t,
-			  int,
-			  dma_addr_t *);
-};
-
 struct xilly_mapping {
 	struct device *device;
 	dma_addr_t dma_addr;
@@ -134,9 +117,7 @@ struct xilly_mapping {
 
 irqreturn_t xillybus_isr(int irq, void *data);
 
-struct xilly_endpoint *xillybus_init_endpoint(struct device *dev,
-					      struct xilly_endpoint_hardware
-					      *ephw);
+struct xilly_endpoint *xillybus_init_endpoint(struct device *dev);
 
 int xillybus_endpoint_discovery(struct xilly_endpoint *endpoint);