root/arch/unicore32/include/asm/io.h

INCLUDED FROM

DEFINITIONS

1. devmem_is_allowed

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * linux/arch/unicore32/include/asm/io.h
   4  *
   5  * Code specific to PKUnity SoC and UniCore ISA
   6  *
   7  * Copyright (C) 2001-2010 GUAN Xue-tao
   8  */
   9 #ifndef __UNICORE_IO_H__
  10 #define __UNICORE_IO_H__
  11 
  12 #ifdef __KERNEL__
  13 
  14 #include <asm/byteorder.h>
  15 #include <asm/memory.h>
  16 
  17 #define PCI_IOBASE      PKUNITY_PCILIO_BASE
  18 #include <asm-generic/io.h>
  19 
  20 /*
  21  * __uc32_ioremap and __uc32_ioremap_cached takes CPU physical address.
  22  */
  23 extern void __iomem *__uc32_ioremap(unsigned long, size_t);
  24 extern void __iomem *__uc32_ioremap_cached(unsigned long, size_t);
  25 extern void __uc32_iounmap(volatile void __iomem *addr);
  26 
  27 /*
  28  * ioremap and friends.
  29  *
  30  * ioremap takes a PCI memory address, as specified in
  31  * Documentation/io-mapping.txt.
  32  *
  33  */
  34 #define ioremap(cookie, size)           __uc32_ioremap(cookie, size)
  35 #define ioremap_cached(cookie, size)    __uc32_ioremap_cached(cookie, size)
  36 #define ioremap_nocache(cookie, size)   __uc32_ioremap(cookie, size)
  37 #define iounmap(cookie)                 __uc32_iounmap(cookie)
  38 
  39 #define readb_relaxed readb
  40 #define readw_relaxed readw
  41 #define readl_relaxed readl
  42 
  43 #define HAVE_ARCH_PIO_SIZE
  44 #define PIO_OFFSET              (unsigned int)(PCI_IOBASE)
  45 #define PIO_MASK                (unsigned int)(IO_SPACE_LIMIT)
  46 #define PIO_RESERVED            (PIO_OFFSET + PIO_MASK + 1)
  47 
  48 #ifdef CONFIG_STRICT_DEVMEM
  49 
  50 #include <linux/ioport.h>
  51 #include <linux/mm.h>
  52 
  53 /*
  54  * devmem_is_allowed() checks to see if /dev/mem access to a certain
  55  * address is valid. The argument is a physical page number.
  56  * We mimic x86 here by disallowing access to system RAM as well as
  57  * device-exclusive MMIO regions. This effectively disable read()/write()
  58  * on /dev/mem.
  59  */
  60 static inline int devmem_is_allowed(unsigned long pfn)
  61 {
  62         if (iomem_is_exclusive(pfn << PAGE_SHIFT))
  63                 return 0;
  64         if (!page_is_ram(pfn))
  65                 return 1;
  66         return 0;
  67 }
  68 
  69 #endif /* CONFIG_STRICT_DEVMEM */
  70 
  71 #endif  /* __KERNEL__ */
  72 #endif  /* __UNICORE_IO_H__ */