ia64: rework iommu probing

ia64 currently organizes the iommu probing along machves, which isn't
very helpful. Instead just try to probe for Intel IOMMUs in mem_init
as they are properly described in ACPI and if none was found initialize
the swiotlb buffer. The HP SBA handling is then only done delayed when
the actual hardware is probed. Only in the case that we actually found
usable IOMMUs we then set up the DMA ops and free the not needed
swiotlb buffer. This scheme gets rid of the need for the dma_init
machvec operation, and the dig_vtd machvec.

Signed-off-by: Christoph Hellwig <[e-mail]>
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Tony Luck <[e-mail]>

arch/ia64/Kconfig

···
 	bool "DIG-compliant"
 	select SWIOTLB
 
-config IA64_DIG_VTD
-	bool "DIG+Intel+IOMMU"
-	select INTEL_IOMMU
-	select PCI_MSI
-
 config IA64_HP_ZX1
 	bool "HP-zx1/sx1000"
 	help

arch/ia64/Makefile

···
 libs-y				+= arch/ia64/lib/
 core-y				+= arch/ia64/kernel/ arch/ia64/mm/
 core-$(CONFIG_IA64_DIG) 	+= arch/ia64/dig/
-core-$(CONFIG_IA64_DIG_VTD) 	+= arch/ia64/dig/
 core-$(CONFIG_IA64_GENERIC) 	+= arch/ia64/dig/
 core-$(CONFIG_IA64_HP_ZX1)	+= arch/ia64/dig/
 core-$(CONFIG_IA64_SGI_UV)	+= arch/ia64/uv/

arch/ia64/dig/Makefile

···
 #
 
 obj-y := setup.o
-ifeq ($(CONFIG_INTEL_IOMMU), y)
-obj-$(CONFIG_IA64_GENERIC) += machvec.o machvec_vtd.o
-else
 obj-$(CONFIG_IA64_GENERIC) += machvec.o
-endif
-

arch/ia64/dig/machvec_vtd.c

···
-#define MACHVEC_PLATFORM_NAME		dig_vtd
-#define MACHVEC_PLATFORM_HEADER		<asm/machvec_dig_vtd.h>
-#include <asm/machvec_init.h>

arch/ia64/hp/common/sba_iommu.c

···
 #include <linux/iommu-helper.h>
 #include <linux/dma-mapping.h>
 #include <linux/prefetch.h>
+#include <linux/swiotlb.h>
 
 #include <asm/delay.h>		/* ia64_get_itc() */
 #include <asm/io.h>
···
 #include <asm/dma.h>
 
 #include <asm/acpi-ext.h>
-
-extern int swiotlb_late_init_with_default_size (size_t size);
 
 #define PFX "IOC: "
 
···
 /* This has to run before acpi_scan_init(). */
 arch_initcall(acpi_sba_ioc_init_acpi);
 
+static int sba_dma_supported (struct device *dev, u64 mask)
+{
+	/* make sure it's at least 32bit capable */
+	return ((mask & 0xFFFFFFFFUL) == 0xFFFFFFFFUL);
+}
+
+static const struct dma_map_ops sba_dma_ops = {
+	.alloc			= sba_alloc_coherent,
+	.free			= sba_free_coherent,
+	.map_page		= sba_map_page,
+	.unmap_page		= sba_unmap_page,
+	.map_sg			= sba_map_sg_attrs,
+	.unmap_sg		= sba_unmap_sg_attrs,
+	.dma_supported		= sba_dma_supported,
+};
+
 static int __init
 sba_init(void)
 {
-	if (!ia64_platform_is("hpzx1"))
-		return 0;
-
-#if defined(CONFIG_IA64_GENERIC)
-	/* If we are booting a kdump kernel, the sba_iommu will
-	 * cause devices that were not shutdown properly to MCA
-	 * as soon as they are turned back on.  Our only option for
-	 * a successful kdump kernel boot is to use the swiotlb.
+	/*
+	 * If we are booting a kdump kernel, the sba_iommu will cause devices
+	 * that were not shutdown properly to MCA as soon as they are turned
+	 * back on.  Our only option for a successful kdump kernel boot is to
+	 * use swiotlb.
 	 */
-	if (is_kdump_kernel()) {
-		dma_ops = NULL;
-		if (swiotlb_late_init_with_default_size(64 * (1<<20)) != 0)
-			panic("Unable to initialize software I/O TLB:"
-				  " Try machvec=dig boot option");
-		machvec_init("dig");
+	if (is_kdump_kernel())
 		return 0;
-	}
-#endif
 
 	/*
 	 * ioc_found should be populated by the acpi_sba_ioc_handler's .attach()
···
 	while (ioc_found)
 		acpi_sba_ioc_add(ioc_found);
 
-	if (!ioc_list) {
-#ifdef CONFIG_IA64_GENERIC
-		/*
-		 * If we didn't find something sba_iommu can claim, we
-		 * need to setup the swiotlb and switch to the dig machvec.
-		 */
-		dma_ops = NULL;
-		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");
-		machvec_init("dig");
-#else
-		panic("Unable to find SBA IOMMU: Try a generic or DIG kernel");
-#endif
+	if (!ioc_list)
 		return 0;
-	}
 
 	{
 		struct pci_bus *b = NULL;
 		while ((b = pci_find_next_bus(b)) != NULL)
 			sba_connect_bus(b);
 	}
+
+	/* no need for swiotlb with the iommu */
+	swiotlb_exit();
+	dma_ops = &sba_dma_ops;
 
 #ifdef CONFIG_PROC_FS
 	ioc_proc_init();
···
 {
 	reserve_sba_gart = 0;
 	return 1;
-}
-
-static int sba_dma_supported (struct device *dev, u64 mask)
-{
-	/* make sure it's at least 32bit capable */
-	return ((mask & 0xFFFFFFFFUL) == 0xFFFFFFFFUL);
 }
 
 __setup("nosbagart", nosbagart);
···
 }
 
 __setup("sbapagesize=",sba_page_override);
-
-const struct dma_map_ops sba_dma_ops = {
-	.alloc			= sba_alloc_coherent,
-	.free			= sba_free_coherent,
-	.map_page		= sba_map_page,
-	.unmap_page		= sba_unmap_page,
-	.map_sg			= sba_map_sg_attrs,
-	.unmap_sg		= sba_unmap_sg_attrs,
-	.dma_supported		= sba_dma_supported,
-};
-
-void sba_dma_init(void)
-{
-	dma_ops = &sba_dma_ops;
-}

arch/ia64/include/asm/acpi.h

···
 	return "uv";
 # elif defined (CONFIG_IA64_DIG)
 	return "dig";
-# elif defined(CONFIG_IA64_DIG_VTD)
-	return "dig_vtd";
 # else
 #	error Unknown platform.  Fix acpi.c.
 # endif

arch/ia64/include/asm/machvec.h

···
 struct device;
 
 typedef void ia64_mv_setup_t (char **);
-typedef void ia64_mv_dma_init (void);
 
 extern void machvec_setup (char **);
 
 # if defined (CONFIG_IA64_DIG)
 #  include <asm/machvec_dig.h>
-# elif defined(CONFIG_IA64_DIG_VTD)
-#  include <asm/machvec_dig_vtd.h>
 # elif defined (CONFIG_IA64_HP_ZX1)
 #  include <asm/machvec_hpzx1.h>
 # elif defined (CONFIG_IA64_SGI_UV)
···
 # else
 #  define ia64_platform_name	ia64_mv.name
 #  define platform_setup	ia64_mv.setup
-#  define platform_dma_init		ia64_mv.dma_init
 # endif
 
 /* __attribute__((__aligned__(16))) is required to make size of the
···
 struct ia64_machine_vector {
 	const char *name;
 	ia64_mv_setup_t *setup;
-	ia64_mv_dma_init *dma_init;
 } __attribute__((__aligned__(16))); /* align attrib? see above comment */
 
 #define MACHVEC_INIT(name)			\
 {						\
 	#name,					\
 	platform_setup,				\
-	platform_dma_init,			\
 }
 
 extern struct ia64_machine_vector ia64_mv;
···
 #  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.
  */
 #ifndef platform_setup
 # define platform_setup			machvec_setup
-#endif
-#ifndef platform_dma_init
-# define platform_dma_init		swiotlb_dma_init
 #endif
 
 #endif /* _ASM_IA64_MACHVEC_H */

arch/ia64/include/asm/machvec_dig_vtd.h

···
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_IA64_MACHVEC_DIG_VTD_h
-#define _ASM_IA64_MACHVEC_DIG_VTD_h
-
-extern ia64_mv_setup_t			dig_setup;
-extern ia64_mv_dma_init			pci_iommu_alloc;
-
-/*
- * This stuff has dual use!
- *
- * For a generic kernel, the macros are used to initialize the
- * platform's machvec structure.  When compiling a non-generic kernel,
- * the macros are used directly.
- */
-#define ia64_platform_name			"dig_vtd"
-#define platform_setup				dig_setup
-#define platform_dma_init			pci_iommu_alloc
-
-#endif /* _ASM_IA64_MACHVEC_DIG_VTD_h */

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;
 
 /*
  * This stuff has dual use!
···
  */
 #define ia64_platform_name			"hpzx1"
 #define platform_setup				dig_setup
-#define platform_dma_init			sba_dma_init
 
 #endif /* _ASM_IA64_MACHVEC_HPZX1_h */

arch/ia64/include/asm/pci.h

···
 	return channel ? isa_irq_to_vector(15) : isa_irq_to_vector(14);
 }
 
-#ifdef CONFIG_INTEL_IOMMU
-extern void pci_iommu_alloc(void);
-#endif
 #endif /* _ASM_IA64_PCI_H */

arch/ia64/kernel/acpi.c

···
 	struct acpi_table_rsdp *rsdp;
 	struct acpi_table_xsdt *xsdt;
 	struct acpi_table_header *hdr;
-#ifdef CONFIG_INTEL_IOMMU
-	u64 i, nentries;
-#endif
 
 	rsdp_phys = acpi_find_rsdp();
 	if (!rsdp_phys) {
···
 		if (!strcmp(hdr->oem_table_id + 4, "UV"))
 			return "uv";
 	}
-
-#ifdef CONFIG_INTEL_IOMMU
-	/* Look for Intel IOMMU */
-	nentries = (hdr->length - sizeof(*hdr)) /
-			 sizeof(xsdt->table_offset_entry[0]);
-	for (i = 0; i < nentries; i++) {
-		hdr = __va(xsdt->table_offset_entry[i]);
-		if (strncmp(hdr->signature, ACPI_SIG_DMAR,
-			sizeof(ACPI_SIG_DMAR) - 1) == 0)
-			return "dig_vtd";
-	}
-#endif
 
 	return "dig";
 }

arch/ia64/kernel/dma-mapping.c

···
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/dma-direct.h>
-#include <linux/swiotlb.h>
 #include <linux/export.h>
 
 /* Set this to 1 if there is a HW IOMMU in the system */
···
 		dma_addr_t dma_addr)
 {
 	return page_to_pfn(virt_to_page(cpu_addr));
-}
-
-void __init swiotlb_dma_init(void)
-{
-	swiotlb_init(1);
 }
 #endif

arch/ia64/kernel/pci-dma.c

···
 
 /* Must execute after PCI subsystem */
 fs_initcall(pci_iommu_init);
-
-void __init pci_iommu_alloc(void)
-{
-	/*
-	 * The order of these functions is important for
-	 * fall-back/fail-over reasons
-	 */
-	detect_intel_iommu();
-
-#ifdef CONFIG_SWIOTLB
-	if (!iommu_detected) {
-#ifdef CONFIG_IA64_GENERIC
-		printk(KERN_INFO "PCI-DMA: Re-initialize machine vector.\n");
-		machvec_init("dig");
-		swiotlb_dma_init();
-#else
-		panic("Unable to find Intel IOMMU");
-#endif /* CONFIG_IA64_GENERIC */
-	}
-#endif /* CONFIG_SWIOTLB */
-}

arch/ia64/mm/init.c

···
 #include <linux/init.h>
 
 #include <linux/dma-noncoherent.h>
+#include <linux/dmar.h>
 #include <linux/efi.h>
 #include <linux/elf.h>
 #include <linux/memblock.h>
···
 #include <linux/proc_fs.h>
 #include <linux/bitops.h>
 #include <linux/kexec.h>
+#include <linux/swiotlb.h>
 
 #include <asm/dma.h>
 #include <asm/io.h>
···
 	BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
 
 	/*
-	 * This needs to be called _after_ the command line has been parsed but _before_
-	 * any drivers that may need the PCI DMA interface are initialized or bootmem has
-	 * been freed.
+	 * This needs to be called _after_ the command line has been parsed but
+	 * _before_ any drivers that may need the PCI DMA interface are
+	 * initialized or bootmem has been freed.
 	 */
-	platform_dma_init();
+#ifdef CONFIG_INTEL_IOMMU
+	detect_intel_iommu();
+	if (!iommu_detected)
+#endif
+#ifdef CONFIG_SWIOTLB
+		swiotlb_init(1);
+#endif
 
 #ifdef CONFIG_FLATMEM
 	BUG_ON(!mem_map);