omap iommu: simple virtual address space management

This patch provides a device drivers, which has a omap iommu, with
address mapping APIs between device virtual address(iommu), physical
address and MPU virtual address.

There are 4 possible patterns for iommu virtual address(iova/da) mapping.

    |iova/			  mapping		iommu_		page
    | da	pa	va	(d)-(p)-(v)		function	type
  ---------------------------------------------------------------------------
  1 | c		c	c	 1 - 1 - 1	  _kmap() / _kunmap()	s
  2 | c		c,a	c	 1 - 1 - 1	_kmalloc()/ _kfree()	s
  3 | c		d	c	 1 - n - 1	  _vmap() / _vunmap()	s
  4 | c		d,a	c	 1 - n - 1	_vmalloc()/ _vfree()	n*

    'iova':	device iommu virtual address
    'da':	alias of 'iova'
    'pa':	physical address
    'va':	mpu virtual address

    'c':	contiguous memory area
    'd':	dicontiguous memory area
    'a':	anonymous memory allocation
    '()':	optional feature

    'n':	a normal page(4KB) size is used.
    's':	multiple iommu superpage(16MB, 1MB, 64KB, 4KB) size is used.

    '*':	not yet, but feasible.
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>

arch/arm/include/asm/mach/map.h

@@ -30,6 +30,14 @@ struct map_desc {
 
 #ifdef CONFIG_MMU
 extern void iotable_init(struct map_desc *, int);
+
+struct mem_type;
+extern const struct mem_type *get_mem_type(unsigned int type);
+/*
+ * external interface to remap single page with appropriate type
+ */
+extern int ioremap_page(unsigned long virt, unsigned long phys,
+			const struct mem_type *mtype);
 #else
 #define iotable_init(map,num)	do { } while (0)
 #endif

arch/arm/mm/ioremap.c

@@ -110,6 +110,12 @@ static int remap_area_pages(unsigned long start, unsigned long pfn,
 	return err;
 }
 
+int ioremap_page(unsigned long virt, unsigned long phys,
+		 const struct mem_type *mtype)
+{
+	return remap_area_pages(virt, __phys_to_pfn(phys), PAGE_SIZE, mtype);
+}
+EXPORT_SYMBOL(ioremap_page);
 
 void __check_kvm_seq(struct mm_struct *mm)
 {

arch/arm/mm/mmu.c

@@ -255,6 +255,7 @@ const struct mem_type *get_mem_type(unsigned int type)
 {
 	return type < ARRAY_SIZE(mem_types) ? &mem_types[type] : NULL;
 }
+EXPORT_SYMBOL(get_mem_type);
 
 /*
  * Adjust the PMD section entries according to the CPU in use.

arch/arm/plat-omap/include/mach/iovmm.h

+/*
+ * omap iommu: simple virtual address space management
+ *
+ * Copyright (C) 2008-2009 Nokia Corporation
+ *
+ * Written by Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __IOMMU_MMAP_H
+#define __IOMMU_MMAP_H
+
+struct iovm_struct {
+	struct iommu		*iommu;	/* iommu object which this belongs to */
+	u32			da_start; /* area definition */
+	u32			da_end;
+	u32			flags; /* IOVMF_: see below */
+	struct list_head	list; /* linked in ascending order */
+	const struct sg_table	*sgt; /* keep 'page' <-> 'da' mapping */
+	void			*va; /* mpu side mapped address */
+};
+
+/*
+ * IOVMF_FLAGS: attribute for iommu virtual memory area(iovma)
+ *
+ * lower 16 bit is used for h/w and upper 16 bit is for s/w.
+ */
+#define IOVMF_SW_SHIFT		16
+#define IOVMF_HW_SIZE		(1 << IOVMF_SW_SHIFT)
+#define IOVMF_HW_MASK		(IOVMF_HW_SIZE - 1)
+#define IOVMF_SW_MASK		(~IOVMF_HW_MASK)UL
+
+/*
+ * iovma: h/w flags derived from cam and ram attribute
+ */
+#define IOVMF_CAM_MASK		(~((1 << 10) - 1))
+#define IOVMF_RAM_MASK		(~IOVMF_CAM_MASK)
+
+#define IOVMF_PGSZ_MASK		(3 << 0)
+#define IOVMF_PGSZ_1M		MMU_CAM_PGSZ_1M
+#define IOVMF_PGSZ_64K		MMU_CAM_PGSZ_64K
+#define IOVMF_PGSZ_4K		MMU_CAM_PGSZ_4K
+#define IOVMF_PGSZ_16M		MMU_CAM_PGSZ_16M
+
+#define IOVMF_ENDIAN_MASK	(1 << 9)
+#define IOVMF_ENDIAN_BIG	MMU_RAM_ENDIAN_BIG
+#define IOVMF_ENDIAN_LITTLE	MMU_RAM_ENDIAN_LITTLE
+
+#define IOVMF_ELSZ_MASK		(3 << 7)
+#define IOVMF_ELSZ_8		MMU_RAM_ELSZ_8
+#define IOVMF_ELSZ_16		MMU_RAM_ELSZ_16
+#define IOVMF_ELSZ_32		MMU_RAM_ELSZ_32
+#define IOVMF_ELSZ_NONE		MMU_RAM_ELSZ_NONE
+
+#define IOVMF_MIXED_MASK	(1 << 6)
+#define IOVMF_MIXED		MMU_RAM_MIXED
+
+/*
+ * iovma: s/w flags, used for mapping and umapping internally.
+ */
+#define IOVMF_MMIO		(1 << IOVMF_SW_SHIFT)
+#define IOVMF_ALLOC		(2 << IOVMF_SW_SHIFT)
+#define IOVMF_ALLOC_MASK	(3 << IOVMF_SW_SHIFT)
+
+/* "superpages" is supported just with physically linear pages */
+#define IOVMF_DISCONT		(1 << (2 + IOVMF_SW_SHIFT))
+#define IOVMF_LINEAR		(2 << (2 + IOVMF_SW_SHIFT))
+#define IOVMF_LINEAR_MASK	(3 << (2 + IOVMF_SW_SHIFT))
+
+#define IOVMF_DA_FIXED		(1 << (4 + IOVMF_SW_SHIFT))
+#define IOVMF_DA_ANON		(2 << (4 + IOVMF_SW_SHIFT))
+#define IOVMF_DA_MASK		(3 << (4 + IOVMF_SW_SHIFT))
+
+
+extern struct iovm_struct *find_iovm_area(struct iommu *obj, u32 da);
+extern u32 iommu_vmap(struct iommu *obj, u32 da,
+			const struct sg_table *sgt, u32 flags);
+extern struct sg_table *iommu_vunmap(struct iommu *obj, u32 da);
+extern u32 iommu_vmalloc(struct iommu *obj, u32 da, size_t bytes,
+			   u32 flags);
+extern void iommu_vfree(struct iommu *obj, const u32 da);
+extern u32 iommu_kmap(struct iommu *obj, u32 da, u32 pa, size_t bytes,
+			u32 flags);
+extern void iommu_kunmap(struct iommu *obj, u32 da);
+extern u32 iommu_kmalloc(struct iommu *obj, u32 da, size_t bytes,
+			   u32 flags);
+extern void iommu_kfree(struct iommu *obj, u32 da);
+
+extern void *da_to_va(struct iommu *obj, u32 da);
+
+#endif /* __IOMMU_MMAP_H */