text: /*
   *  arch/arm/include/asm/memory.h
   *
   *  Copyright (C) 2000-2002 Russell King
   *  modification for nommu, Hyok S. Choi, 2004
   *
   * 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.
   *
   *  Note: this file should not be included by non-asm/.h files
   */
  #ifndef __ASM_ARM_MEMORY_H
  #define __ASM_ARM_MEMORY_H
  
  #include <linux/compiler.h>
  #include <linux/const.h>
  #include <linux/types.h>
  #include <linux/sizes.h>
  
  #ifdef CONFIG_NEED_MACH_MEMORY_H
  #include <mach/memory.h>
  #endif
  
  /*
   * Allow for constants defined here to be used from assembly code
   * by prepending the UL suffix only with actual C code compilation.
   */
  #define UL(x) _AC(x, UL)
  
  /* PAGE_OFFSET - the virtual address of the start of the kernel image */
  #define PAGE_OFFSET		UL(CONFIG_PAGE_OFFSET)
  
  #ifdef CONFIG_MMU
  
  /*
   * TASK_SIZE - the maximum size of a user space task.
   * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area
   */
  #define TASK_SIZE		(UL(CONFIG_PAGE_OFFSET) - UL(SZ_16M))
  #define TASK_UNMAPPED_BASE	ALIGN(TASK_SIZE / 3, SZ_16M)
  
  /*
   * The maximum size of a 26-bit user space task.
   */
  #define TASK_SIZE_26		(UL(1) << 26)
  
  /*
   * The module space lives between the addresses given by TASK_SIZE
   * and PAGE_OFFSET - it must be within 32MB of the kernel text.
   */
  #ifndef CONFIG_THUMB2_KERNEL
  #define MODULES_VADDR		(PAGE_OFFSET - SZ_16M)
  #else
  /* smaller range for Thumb-2 symbols relocation (2^24)*/
  #define MODULES_VADDR		(PAGE_OFFSET - SZ_8M)
  #endif
  
  #if TASK_SIZE > MODULES_VADDR
  #error Top of user space clashes with start of module space
  #endif
  
  /*
   * The highmem pkmap virtual space shares the end of the module area.
   */
  #ifdef CONFIG_HIGHMEM
  #define MODULES_END		(PAGE_OFFSET - PMD_SIZE)
  #else
  #define MODULES_END		(PAGE_OFFSET)
  #endif
  
  /*
   * The XIP kernel gets mapped at the bottom of the module vm area.
   * Since we use sections to map it, this macro replaces the physical address
   * with its virtual address while keeping offset from the base section.
   */
  #define XIP_VIRT_ADDR(physaddr)  (MODULES_VADDR + ((physaddr) & 0x000fffff))
  
  /*
   * Allow 16MB-aligned ioremap pages
   */
  #define IOREMAP_MAX_ORDER	24
  
  #else /* CONFIG_MMU */
  
  /*
   * The limitation of user task size can grow up to the end of free ram region.
   * It is difficult to define and perhaps will never meet the original meaning
   * of this define that was meant to.
   * Fortunately, there is no reference for this in noMMU mode, for now.
   */
  #define TASK_SIZE		UL(0xffffffff)
  
  #ifndef TASK_UNMAPPED_BASE
  #define TASK_UNMAPPED_BASE	UL(0x00000000)
  #endif
  
  #ifndef END_MEM
  #define END_MEM     		(UL(CONFIG_DRAM_BASE) + CONFIG_DRAM_SIZE)
  #endif
  
  /*
   * The module can be at any place in ram in nommu mode.
   */
  #define MODULES_END		(END_MEM)
  #define MODULES_VADDR		PAGE_OFFSET
  
  #define XIP_VIRT_ADDR(physaddr)  (physaddr)
  
  #endif /* !CONFIG_MMU */
  
  /*
   * We fix the TCM memories max 32 KiB ITCM resp DTCM at these
   * locations
   */
  #ifdef CONFIG_HAVE_TCM
  #define ITCM_OFFSET	UL(0xfffe0000)
  #define DTCM_OFFSET	UL(0xfffe8000)
  #endif
  
  /*
   * Convert a physical address to a Page Frame Number and back
   */
  #define	__phys_to_pfn(paddr)	((unsigned long)((paddr) >> PAGE_SHIFT))
  #define	__pfn_to_phys(pfn)	((phys_addr_t)(pfn) << PAGE_SHIFT)
  
  /*
   * Convert a page to/from a physical address
   */
  #define page_to_phys(page)	(__pfn_to_phys(page_to_pfn(page)))
  #define phys_to_page(phys)	(pfn_to_page(__phys_to_pfn(phys)))
  
  /*
   * PLAT_PHYS_OFFSET is the offset (from zero) of the start of physical
   * memory.  This is used for XIP and NoMMU kernels, and on platforms that don't
   * have CONFIG_ARM_PATCH_PHYS_VIRT. Assembly code must always use
   * PLAT_PHYS_OFFSET and not PHYS_OFFSET.
   */
  #define PLAT_PHYS_OFFSET	UL(CONFIG_PHYS_OFFSET)
  
  #ifndef __ASSEMBLY__
  
  /*
   * Physical vs virtual RAM address space conversion.  These are
   * private definitions which should NOT be used outside memory.h
   * files.  Use virt_to_phys/phys_to_virt/__pa/__va instead.
   *
   * PFNs are used to describe any physical page; this means
   * PFN 0 == physical address 0.
   */
  #if defined(__virt_to_phys)
  #define PHYS_OFFSET	PLAT_PHYS_OFFSET
  #define PHYS_PFN_OFFSET	((unsigned long)(PHYS_OFFSET >> PAGE_SHIFT))
  
  #define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
  
  #elif defined(CONFIG_ARM_PATCH_PHYS_VIRT)
  
  /*
   * Constants used to force the right instruction encodings and shifts
   * so that all we need to do is modify the 8-bit constant field.
   */
  #define __PV_BITS_31_24	0x81000000
  #define __PV_BITS_7_0	0x81
  
  extern unsigned long __pv_phys_pfn_offset;
  extern u64 __pv_offset;
  extern void fixup_pv_table(const void *, unsigned long);
  extern const void *__pv_table_begin, *__pv_table_end;
  
  #define PHYS_OFFSET	((phys_addr_t)__pv_phys_pfn_offset << PAGE_SHIFT)
  #define PHYS_PFN_OFFSET	(__pv_phys_pfn_offset)
  
  #define virt_to_pfn(kaddr) \
  	((((unsigned long)(kaddr) - PAGE_OFFSET) >> PAGE_SHIFT) + \
  	 PHYS_PFN_OFFSET)
  
  #define __pv_stub(from,to,instr,type)			\
  	__asm__("@ __pv_stub\n"				\
  	"1:	" instr "	%0, %1, %2\n"		\
  	"	.pushsection .pv_table,\"a\"\n"		\
  	"	.long	1b\n"				\
  	"	.popsection\n"				\
  	: "=r" (to)					\
  	: "r" (from), "I" (type))
  
  #define __pv_stub_mov_hi(t)				\
  	__asm__ volatile("@ __pv_stub_mov\n"		\
  	"1:	mov	%R0, %1\n"			\
  	"	.pushsection .pv_table,\"a\"\n"		\
  	"	.long	1b\n"				\
  	"	.popsection\n"				\
  	: "=r" (t)					\
  	: "I" (__PV_BITS_7_0))
  
  #define __pv_add_carry_stub(x, y)			\
  	__asm__ volatile("@ __pv_add_carry_stub\n"	\
  	"1:	adds	%Q0, %1, %2\n"			\
  	"	adc	%R0, %R0, #0\n"			\
  	"	.pushsection .pv_table,\"a\"\n"		\
  	"	.long	1b\n"				\
  	"	.popsection\n"				\
  	: "+r" (y)					\
  	: "r" (x), "I" (__PV_BITS_31_24)		\
  	: "cc")
  
  static inline phys_addr_t __virt_to_phys(unsigned long x)
  {
  	phys_addr_t t;
  
  	if (sizeof(phys_addr_t) == 4) {
  		__pv_stub(x, t, "add", __PV_BITS_31_24);
  	} else {
  		__pv_stub_mov_hi(t);
  		__pv_add_carry_stub(x, t);
  	}
  	return t;
  }
  
  static inline unsigned long __phys_to_virt(phys_addr_t x)
  {
  	unsigned long t;
  
  	/*
  	 * 'unsigned long' cast discard upper word when
  	 * phys_addr_t is 64 bit, and makes sure that inline
  	 * assembler expression receives 32 bit argument
  	 * in place where 'r' 32 bit operand is expected.
  	 */
  	__pv_stub((unsigned long) x, t, "sub", __PV_BITS_31_24);
  	return t;
  }
  
  #else
  
  #define PHYS_OFFSET	PLAT_PHYS_OFFSET
  #define PHYS_PFN_OFFSET	((unsigned long)(PHYS_OFFSET >> PAGE_SHIFT))
  
  static inline phys_addr_t __virt_to_phys(unsigned long x)
  {
  	return (phys_addr_t)x - PAGE_OFFSET + PHYS_OFFSET;
  }
  
  static inline unsigned long __phys_to_virt(phys_addr_t x)
  {
  	return x - PHYS_OFFSET + PAGE_OFFSET;
  }
  
  #define virt_to_pfn(kaddr) \
  	((((unsigned long)(kaddr) - PAGE_OFFSET) >> PAGE_SHIFT) + \
  	 PHYS_PFN_OFFSET)
  
  #endif
  
  /*
   * These are *only* valid on the kernel direct mapped RAM memory.
   * Note: Drivers should NOT use these.  They are the wrong
   * translation for translating DMA addresses.  Use the driver
   * DMA support - see dma-mapping.h.
   */
  #define virt_to_phys virt_to_phys
  static inline phys_addr_t virt_to_phys(const volatile void *x)
  {
  	return __virt_to_phys((unsigned long)(x));
  }
  
  #define phys_to_virt phys_to_virt
  static inline void *phys_to_virt(phys_addr_t x)
  {
  	return (void *)__phys_to_virt(x);
  }
  
  /*
   * Drivers should NOT use these either.
   */
  #define __pa(x)			__virt_to_phys((unsigned long)(x))
  #define __va(x)			((void *)__phys_to_virt((phys_addr_t)(x)))
  #define pfn_to_kaddr(pfn)	__va((phys_addr_t)(pfn) << PAGE_SHIFT)
  
  extern phys_addr_t (*arch_virt_to_idmap)(unsigned long x);
  
  /*
   * These are for systems that have a hardware interconnect supported alias of
   * physical memory for idmap purposes.  Most cases should leave these
   * untouched.
   */
  static inline phys_addr_t __virt_to_idmap(unsigned long x)
  {
  	if (IS_ENABLED(CONFIG_MMU) && arch_virt_to_idmap)
  		return arch_virt_to_idmap(x);
  	else
  		return __virt_to_phys(x);
  }
  
  #define virt_to_idmap(x)	__virt_to_idmap((unsigned long)(x))
  
  /*
   * Virtual <-> DMA view memory address translations
   * Again, these are *only* valid on the kernel direct mapped RAM
   * memory.  Use of these is *deprecated* (and that doesn't mean
   * use the __ prefixed forms instead.)  See dma-mapping.h.
   */
  #ifndef __virt_to_bus
  #define __virt_to_bus	__virt_to_phys
  #define __bus_to_virt	__phys_to_virt
  #define __pfn_to_bus(x)	__pfn_to_phys(x)
  #define __bus_to_pfn(x)	__phys_to_pfn(x)
  #endif
  
  #ifdef CONFIG_VIRT_TO_BUS
  #define virt_to_bus virt_to_bus
  static inline __deprecated unsigned long virt_to_bus(void *x)
  {
  	return __virt_to_bus((unsigned long)x);
  }
  
  #define bus_to_virt bus_to_virt
  static inline __deprecated void *bus_to_virt(unsigned long x)
  {
  	return (void *)__bus_to_virt(x);
  }
  #endif
  
  /*
   * Conversion between a struct page and a physical address.
   *
   *  page_to_pfn(page)	convert a struct page * to a PFN number
   *  pfn_to_page(pfn)	convert a _valid_ PFN number to struct page *
   *
   *  virt_to_page(k)	convert a _valid_ virtual address to struct page *
   *  virt_addr_valid(k)	indicates whether a virtual address is valid
   */
  #define ARCH_PFN_OFFSET		PHYS_PFN_OFFSET
  
  #define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))
  #define virt_addr_valid(kaddr)	(((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory) \
  					&& pfn_valid(virt_to_pfn(kaddr)))
  
  #endif
  
  #include <asm-generic/memory_model.h>
  
  #endif
  