ARM/dma-mapping: use dma-direct unconditionally

Use dma-direct unconditionally on arm.  It has already been used for
some time for LPAE and nommu configurations.

This mostly changes the streaming mapping implementation and the (simple)
coherent allocator for device that are DMA coherent.  The existing
complex allocator for uncached mappings for non-coherent devices is still
used as is using the arch_dma_alloc/arch_dma_free hooks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Andre Przywara <andre.przywara@arm.com> [highbank]
Tested-by: Marc Zyngier <maz@kernel.org>

arch/arm/Kconfig

@@ -19,8 +19,8 @@ config ARM
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
 	select ARCH_HAS_STRICT_MODULE_RWX if MMU
-	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if SWIOTLB || !MMU
-	select ARCH_HAS_SYNC_DMA_FOR_CPU if SWIOTLB || !MMU
+	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
+	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_TEARDOWN_DMA_OPS if MMU
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAVE_CUSTOM_GPIO_H

arch/arm/include/asm/dma-mapping.h

-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ASMARM_DMA_MAPPING_H
-#define ASMARM_DMA_MAPPING_H
-
-#ifdef __KERNEL__
-
-#include <linux/mm_types.h>
-#include <linux/scatterlist.h>
-
-#include <xen/xen.h>
-#include <asm/xen/hypervisor.h>
-
-extern const struct dma_map_ops arm_dma_ops;
-extern const struct dma_map_ops arm_coherent_dma_ops;
-
-static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
-{
-	if (IS_ENABLED(CONFIG_MMU) && !IS_ENABLED(CONFIG_ARM_LPAE))
-		return &arm_dma_ops;
-	return NULL;
-}
-
-#endif /* __KERNEL__ */
-#endif

arch/arm/mach-highbank/highbank.c

@@ -98,7 +98,7 @@ static int highbank_platform_notifier(struct notifier_block *nb,
 	if (of_property_read_bool(dev->of_node, "dma-coherent")) {
 		val = readl(sregs_base + reg);
 		writel(val | 0xff01, sregs_base + reg);
-		set_dma_ops(dev, &arm_coherent_dma_ops);
+		dev->dma_coherent = true;
 	}
 
 	return NOTIFY_OK;

arch/arm/mach-mvebu/coherency.c

@@ -98,7 +98,7 @@ static int mvebu_hwcc_notifier(struct notifier_block *nb,
 
 	if (event != BUS_NOTIFY_ADD_DEVICE)
 		return NOTIFY_DONE;
-	set_dma_ops(dev, &arm_coherent_dma_ops);
+	dev->dma_coherent = true;
 
 	return NOTIFY_OK;
 }