ARM: ixp4xx: Drop custom DMA coherency and bouncing

The new PCI driver does not need any of this stuff, so just
drop it.

Cc: iommu@lists.linux-foundation.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220211223238.648934-12-linus.walleij@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/Kconfig

@@ -217,9 +217,6 @@ config ARCH_MAY_HAVE_PC_FDC
 config ARCH_SUPPORTS_UPROBES
 	def_bool y
 
-config ARCH_HAS_DMA_SET_COHERENT_MASK
-	bool
-
 config GENERIC_ISA_DMA
 	bool
 
@@ -381,10 +378,8 @@ config ARCH_IOP32X
 config ARCH_IXP4XX
 	bool "IXP4xx-based"
 	depends on MMU
-	select ARCH_HAS_DMA_SET_COHERENT_MASK
 	select ARCH_SUPPORTS_BIG_ENDIAN
 	select CPU_XSCALE
-	select DMABOUNCE if PCI
 	select GENERIC_IRQ_MULTI_HANDLER
 	select GPIO_IXP4XX
 	select GPIOLIB

arch/arm/mach-ixp4xx/common.c

@@ -30,7 +30,6 @@
 #include <linux/soc/ixp4xx/cpu.h>
 #include <linux/irqchip/irq-ixp4xx.h>
 #include <linux/platform_data/timer-ixp4xx.h>
-#include <linux/dma-map-ops.h>
 #include <mach/hardware.h>
 #include <linux/uaccess.h>
 #include <asm/page.h>
@@ -330,59 +329,3 @@ void ixp4xx_restart(enum reboot_mode mode, const char *cmd)
 		*IXP4XX_OSWE = IXP4XX_WDT_RESET_ENABLE | IXP4XX_WDT_COUNT_ENABLE;
 	}
 }
-
-#ifdef CONFIG_PCI
-static int ixp4xx_needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
-{
-	return (dma_addr + size) > SZ_64M;
-}
-
-static int ixp4xx_platform_notify_remove(struct device *dev)
-{
-	if (dev_is_pci(dev))
-		dmabounce_unregister_dev(dev);
-
-	return 0;
-}
-#endif
-
-/*
- * Setup DMA mask to 64MB on PCI devices and 4 GB on all other things.
- */
-static int ixp4xx_platform_notify(struct device *dev)
-{
-	dev->dma_mask = &dev->coherent_dma_mask;
-
-#ifdef CONFIG_PCI
-	if (dev_is_pci(dev)) {
-		dev->coherent_dma_mask = DMA_BIT_MASK(28); /* 64 MB */
-		dmabounce_register_dev(dev, 2048, 4096, ixp4xx_needs_bounce);
-		return 0;
-	}
-#endif
-
-	dev->coherent_dma_mask = DMA_BIT_MASK(32);
-	return 0;
-}
-
-int dma_set_coherent_mask(struct device *dev, u64 mask)
-{
-	if (dev_is_pci(dev))
-		mask &= DMA_BIT_MASK(28); /* 64 MB */
-
-	if ((mask & DMA_BIT_MASK(28)) == DMA_BIT_MASK(28)) {
-		dev->coherent_dma_mask = mask;
-		return 0;
-	}
-
-	return -EIO;		/* device wanted sub-64MB mask */
-}
-EXPORT_SYMBOL(dma_set_coherent_mask);
-
-void __init ixp4xx_init_early(void)
-{
-	platform_notify = ixp4xx_platform_notify;
-#ifdef CONFIG_PCI
-	platform_notify_remove = ixp4xx_platform_notify_remove;
-#endif
-}

kernel/dma/mapping.c

@@ -745,7 +745,6 @@ int dma_set_mask(struct device *dev, u64 mask)
 }
 EXPORT_SYMBOL(dma_set_mask);
 
-#ifndef CONFIG_ARCH_HAS_DMA_SET_COHERENT_MASK
 int dma_set_coherent_mask(struct device *dev, u64 mask)
 {
 	/*
@@ -761,7 +760,6 @@ int dma_set_coherent_mask(struct device *dev, u64 mask)
 	return 0;
 }
 EXPORT_SYMBOL(dma_set_coherent_mask);
-#endif
 
 size_t dma_max_mapping_size(struct device *dev)
 {