dma-mapping, powerpc: simplify the arch dma_set_mask override

Instead of letting the architecture supply all of dma_set_mask just
give it an additional hook selected by Kconfig.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/Kconfig

@@ -886,6 +886,7 @@ config FSL_SOC
 
 config FSL_PCI
  	bool
+	select ARCH_HAS_DMA_SET_MASK
 	select PPC_INDIRECT_PCI
 	select PCI_QUIRKS
 

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

@@ -110,7 +110,5 @@ static inline void set_dma_offset(struct device *dev, dma_addr_t off)
 		dev->archdata.dma_offset = off;
 }
 
-#define HAVE_ARCH_DMA_SET_MASK 1
-
 #endif /* __KERNEL__ */
 #endif	/* _ASM_DMA_MAPPING_H */

arch/powerpc/include/asm/machdep.h

@@ -47,7 +47,7 @@ struct machdep_calls {
 #endif
 #endif /* CONFIG_PPC64 */
 
-	int		(*dma_set_mask)(struct device *dev, u64 dma_mask);
+	void		(*dma_set_mask)(struct device *dev, u64 dma_mask);
 
 	int		(*probe)(void);
 	void		(*setup_arch)(void); /* Optional, may be NULL */

arch/powerpc/kernel/Makefile

@@ -105,6 +105,7 @@ obj-$(CONFIG_UPROBES)		+= uprobes.o
 obj-$(CONFIG_PPC_UDBG_16550)	+= legacy_serial.o udbg_16550.o
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-$(CONFIG_SWIOTLB)		+= dma-swiotlb.o
+obj-$(CONFIG_ARCH_HAS_DMA_SET_MASK) += dma-mask.o
 
 pci64-$(CONFIG_PPC64)		+= pci_dn.o pci-hotplug.o isa-bridge.o
 obj-$(CONFIG_PCI)		+= pci_$(BITS).o $(pci64-y) \

arch/powerpc/kernel/dma-mask.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/dma-mapping.h>
+#include <linux/export.h>
+#include <asm/machdep.h>
+
+void arch_dma_set_mask(struct device *dev, u64 dma_mask)
+{
+	if (ppc_md.dma_set_mask)
+		ppc_md.dma_set_mask(dev, dma_mask);
+}
+EXPORT_SYMBOL(arch_dma_set_mask);

arch/powerpc/kernel/dma.c

@@ -234,18 +234,6 @@ const struct dma_map_ops dma_nommu_ops = {
 };
 EXPORT_SYMBOL(dma_nommu_ops);
 
-int dma_set_mask(struct device *dev, u64 dma_mask)
-{
-	if (ppc_md.dma_set_mask)
-		return ppc_md.dma_set_mask(dev, dma_mask);
-
-	if (!dev->dma_mask || !dma_supported(dev, dma_mask))
-		return -EIO;
-	*dev->dma_mask = dma_mask;
-	return 0;
-}
-EXPORT_SYMBOL(dma_set_mask);
-
 static int __init dma_init(void)
 {
 #ifdef CONFIG_IBMVIO

arch/powerpc/sysdev/fsl_pci.c

@@ -133,11 +133,8 @@ static void setup_swiotlb_ops(struct pci_controller *hose)
 static inline void setup_swiotlb_ops(struct pci_controller *hose) {}
 #endif
 
-static int fsl_pci_dma_set_mask(struct device *dev, u64 dma_mask)
+static void fsl_pci_dma_set_mask(struct device *dev, u64 dma_mask)
 {
-	if (!dev->dma_mask || !dma_supported(dev, dma_mask))
-		return -EIO;
-
 	/*
 	 * Fix up PCI devices that are able to DMA to the large inbound
 	 * mapping that allows addressing any RAM address from across PCI.
@@ -147,9 +144,6 @@ static int fsl_pci_dma_set_mask(struct device *dev, u64 dma_mask)
 		set_dma_ops(dev, &dma_nommu_ops);
 		set_dma_offset(dev, pci64_dma_offset);
 	}
-
-	*dev->dma_mask = dma_mask;
-	return 0;
 }
 
 static int setup_one_atmu(struct ccsr_pci __iomem *pci,

kernel/dma/Kconfig

@@ -16,6 +16,9 @@ config ARCH_DMA_ADDR_T_64BIT
 config ARCH_HAS_DMA_COHERENCE_H
 	bool
 
+config ARCH_HAS_DMA_SET_MASK
+	bool
+
 config HAVE_GENERIC_DMA_COHERENT
 	bool
 

kernel/dma/mapping.c

@@ -316,18 +316,23 @@ int dma_supported(struct device *dev, u64 mask)
 }
 EXPORT_SYMBOL(dma_supported);
 
-#ifndef HAVE_ARCH_DMA_SET_MASK
+#ifdef CONFIG_ARCH_HAS_DMA_SET_MASK
+void arch_dma_set_mask(struct device *dev, u64 mask);
+#else
+#define arch_dma_set_mask(dev, mask)	do { } while (0)
+#endif
+
 int dma_set_mask(struct device *dev, u64 mask)
 {
 	if (!dev->dma_mask || !dma_supported(dev, mask))
 		return -EIO;
 
+	arch_dma_set_mask(dev, mask);
 	dma_check_mask(dev, mask);
 	*dev->dma_mask = mask;
 	return 0;
 }
 EXPORT_SYMBOL(dma_set_mask);
-#endif
 
 #ifndef CONFIG_ARCH_HAS_DMA_SET_COHERENT_MASK
 int dma_set_coherent_mask(struct device *dev, u64 mask)