set up dma_ops appropriately

This patch introduces a global pointer, dma_ops, which points to an
appropriate dma_mapping_ops that the kernel should use. This is a
common way to handle multiple dma_mapping_ops (X86, POWER, and SPARC).

dma_ops is set in platform_dma_init. We also set it by hand where
machvec_init is callev via subsys_initcall.

- IA64_DIG_VTD uses vtd_dma_ops.
- IA64_HP_ZX1 uses sba_dma_ops.
- IA64_HP_ZX1_SWIOTLB uses hwsw_dma_ops.
- IA64_SGI_SN2 uses sn_dma_ops.
- The rest use swiotlb_dma_ops.

Signed-off-by: FUJITA Tomonori <[e-mail]>
Acked-by: Tony Luck <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

arch/ia64/hp/common/hwsw_iommu.c

···
 	return dev && dev->dma_mask && !hwiommu_dma_supported(dev, *dev->dma_mask);
 }
 
+struct dma_mapping_ops hwsw_dma_ops;
+
 void __init
 hwsw_init (void)
 {
+	dma_ops = &hwsw_dma_ops;
 	/* default to a smallish 2MB sw I/O TLB */
 	if (swiotlb_late_init_with_default_size (2 * (1<<20)) != 0) {
 #ifdef CONFIG_IA64_GENERIC

arch/ia64/hp/common/sba_iommu.c

···
 	},
 };
 
+extern struct dma_mapping_ops swiotlb_dma_ops;
+
 static int __init
 sba_init(void)
 {
···
 	 * a successful kdump kernel boot is to use the swiotlb.
 	 */
 	if (is_kdump_kernel()) {
+		dma_ops = &swiotlb_dma_ops;
 		if (swiotlb_late_init_with_default_size(64 * (1<<20)) != 0)
 			panic("Unable to initialize software I/O TLB:"
 				  " Try machvec=dig boot option");
···
 		 * If we didn't find something sba_iommu can claim, we
 		 * need to setup the swiotlb and switch to the dig machvec.
 		 */
+		dma_ops = &swiotlb_dma_ops;
 		if (swiotlb_late_init_with_default_size(64 * (1<<20)) != 0)
 			panic("Unable to find SBA IOMMU or initialize "
 			      "software I/O TLB: Try machvec=dig boot option");
···
 	.dma_supported_op	= sba_dma_supported,
 	.mapping_error		= sba_dma_mapping_error,
 };
+
+void sba_dma_init(void)
+{
+	dma_ops = &sba_dma_ops;
+}

arch/ia64/include/asm/machvec.h

···
 #  error Unknown configuration.  Update arch/ia64/include/asm/machvec.h.
 # endif /* CONFIG_IA64_GENERIC */
 
+extern void swiotlb_dma_init(void);
+
 /*
  * Define default versions so we can extend machvec for new platforms without having
  * to update the machvec files for all existing platforms.
···
 # define platform_kernel_launch_event	machvec_noop
 #endif
 #ifndef platform_dma_init
-# define platform_dma_init		swiotlb_init
+# define platform_dma_init		swiotlb_dma_init
 #endif
 #ifndef platform_dma_alloc_coherent
 # define platform_dma_alloc_coherent	swiotlb_alloc_coherent

arch/ia64/include/asm/machvec_hpzx1.h

···
 #define _ASM_IA64_MACHVEC_HPZX1_h
 
 extern ia64_mv_setup_t			dig_setup;
+extern ia64_mv_dma_init			sba_dma_init;
 extern ia64_mv_dma_alloc_coherent	sba_alloc_coherent;
 extern ia64_mv_dma_free_coherent	sba_free_coherent;
 extern ia64_mv_dma_map_single_attrs	sba_map_single_attrs;
···
  */
 #define platform_name				"hpzx1"
 #define platform_setup				dig_setup
-#define platform_dma_init			machvec_noop
+#define platform_dma_init			sba_dma_init
 #define platform_dma_alloc_coherent		sba_alloc_coherent
 #define platform_dma_free_coherent		sba_free_coherent
 #define platform_dma_map_single_attrs		sba_map_single_attrs

arch/ia64/include/asm/machvec_sn2.h

···
 extern ia64_mv_readw_t __sn_readw_relaxed;
 extern ia64_mv_readl_t __sn_readl_relaxed;
 extern ia64_mv_readq_t __sn_readq_relaxed;
+extern ia64_mv_dma_init			sn_dma_init;
 extern ia64_mv_dma_alloc_coherent	sn_dma_alloc_coherent;
 extern ia64_mv_dma_free_coherent	sn_dma_free_coherent;
 extern ia64_mv_dma_map_single_attrs	sn_dma_map_single_attrs;
···
 #define platform_pci_get_legacy_mem	sn_pci_get_legacy_mem
 #define platform_pci_legacy_read	sn_pci_legacy_read
 #define platform_pci_legacy_write	sn_pci_legacy_write
-#define platform_dma_init		machvec_noop
+#define platform_dma_init		sn_dma_init
 #define platform_dma_alloc_coherent	sn_dma_alloc_coherent
 #define platform_dma_free_coherent	sn_dma_free_coherent
 #define platform_dma_map_single_attrs	sn_dma_map_single_attrs

arch/ia64/kernel/Makefile

···
 obj-y := acpi.o entry.o efi.o efi_stub.o gate-data.o fsys.o ia64_ksyms.o irq.o irq_ia64.o	\
 	 irq_lsapic.o ivt.o machvec.o pal.o patch.o process.o perfmon.o ptrace.o sal.o		\
 	 salinfo.o setup.o signal.o sys_ia64.o time.o traps.o unaligned.o \
-	 unwind.o mca.o mca_asm.o topology.o
+	 unwind.o mca.o mca_asm.o topology.o dma-mapping.o
 
 obj-$(CONFIG_IA64_BRL_EMU)	+= brl_emu.o
 obj-$(CONFIG_IA64_GENERIC)	+= acpi-ext.o

arch/ia64/kernel/dma-mapping.c

···
+#include <linux/dma-mapping.h>
+
+struct dma_mapping_ops *dma_ops;
+EXPORT_SYMBOL(dma_ops);

arch/ia64/kernel/pci-dma.c

···
 	.dma_mask = &fallback_dev.coherent_dma_mask,
 };
 
+extern struct dma_mapping_ops vtd_dma_ops;
+
 void __init pci_iommu_alloc(void)
 {
+	dma_ops = &vtd_dma_ops;
 	/*
 	 * The order of these functions is important for
 	 * fall-back/fail-over reasons
···
 {
 	return;
 }
-
-struct dma_mapping_ops *dma_ops;
-EXPORT_SYMBOL(dma_ops);
 
 int iommu_dma_supported(struct device *dev, u64 mask)
 {

arch/ia64/kernel/pci-swiotlb.c

···
 	.mapping_error = swiotlb_dma_mapping_error,
 };
 
+void swiotlb_dma_init(void)
+{
+	dma_ops = &swiotlb_dma_ops;
+	swiotlb_init();
+}
+
 void __init pci_swiotlb_init(void)
 {
 	if (!iommu_detected) {

arch/ia64/sn/pci/pci_dma.c

···
 	.mapping_error		= sn_dma_mapping_error,
 	.dma_supported_op	= sn_dma_supported,
 };
+
+void sn_dma_init(void)
+{
+	dma_ops = &sn_dma_ops;
+}