arch/microblaze/mm/consistent.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Microblaze support for cache consistent memory.
   4  * Copyright (C) 2010 Michal Simek <monstr@monstr.eu>
   5  * Copyright (C) 2010 PetaLogix
   6  * Copyright (C) 2005 John Williams <jwilliams@itee.uq.edu.au>
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/string.h>
  11 #include <linux/types.h>
  12 #include <linux/mm.h>
  13 #include <linux/init.h>
  14 #include <linux/dma-noncoherent.h>
  15 #include <asm/cpuinfo.h>
  16 #include <asm/cacheflush.h>
  17
  18 void arch_dma_prep_coherent(struct page *page, size_t size)
  19 {
  20         phys_addr_t paddr = page_to_phys(page);
  21
  22         flush_dcache_range(paddr, paddr + size);
  23 }
  24
  25 #ifndef CONFIG_MMU
  26 /*
  27  * Consistent memory allocators. Used for DMA devices that want to share
  28  * uncached memory with the processor core.  My crufty no-MMU approach is
  29  * simple.  In the HW platform we can optionally mirror the DDR up above the
  30  * processor cacheable region.  So, memory accessed in this mirror region will
  31  * not be cached.  It's alloced from the same pool as normal memory, but the
  32  * handle we return is shifted up into the uncached region.  This will no doubt
  33  * cause big problems if memory allocated here is not also freed properly. -- JW
  34  *
  35  * I have to use dcache values because I can't relate on ram size:
  36  */
  37 #ifdef CONFIG_XILINX_UNCACHED_SHADOW
  38 #define UNCACHED_SHADOW_MASK (cpuinfo.dcache_high - cpuinfo.dcache_base + 1)
  39 #else
  40 #define UNCACHED_SHADOW_MASK 0
  41 #endif /* CONFIG_XILINX_UNCACHED_SHADOW */
  42
  43 void *uncached_kernel_address(void *ptr)
  44 {
  45         unsigned long addr = (unsigned long)ptr;
  46
  47         addr |= UNCACHED_SHADOW_MASK;
  48         if (addr > cpuinfo.dcache_base && addr < cpuinfo.dcache_high)
  49                 pr_warn("ERROR: Your cache coherent area is CACHED!!!\n");
  50         return (void *)addr;
  51 }
  52
  53 void *cached_kernel_address(void *ptr)
  54 {
  55         unsigned long addr = (unsigned long)ptr;
  56
  57         return (void *)(addr & ~UNCACHED_SHADOW_MASK);
  58 }
  59 #endif /* CONFIG_MMU */