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 *arch_dma_set_uncached(void *ptr, size_t size) 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 #endif /* CONFIG_MMU */ 53