1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * DMA implementation for Hexagon 4 * 5 * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved. 6 */ 7 8 #include <linux/dma-noncoherent.h> 9 #include <linux/memblock.h> 10 #include <linux/genalloc.h> 11 #include <linux/module.h> 12 #include <asm/page.h> 13 14 static struct gen_pool *coherent_pool; 15 16 17 /* Allocates from a pool of uncached memory that was reserved at boot time */ 18 19 void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_addr, 20 gfp_t flag, unsigned long attrs) 21 { 22 void *ret; 23 24 /* 25 * Our max_low_pfn should have been backed off by 16MB in 26 * mm/init.c to create DMA coherent space. Use that as the VA 27 * for the pool. 28 */ 29 30 if (coherent_pool == NULL) { 31 coherent_pool = gen_pool_create(PAGE_SHIFT, -1); 32 33 if (coherent_pool == NULL) 34 panic("Can't create %s() memory pool!", __func__); 35 else 36 gen_pool_add(coherent_pool, 37 (unsigned long)pfn_to_virt(max_low_pfn), 38 hexagon_coherent_pool_size, -1); 39 } 40 41 ret = (void *) gen_pool_alloc(coherent_pool, size); 42 43 if (ret) { 44 memset(ret, 0, size); 45 *dma_addr = (dma_addr_t) virt_to_phys(ret); 46 } else 47 *dma_addr = ~0; 48 49 return ret; 50 } 51 52 void arch_dma_free(struct device *dev, size_t size, void *vaddr, 53 dma_addr_t dma_addr, unsigned long attrs) 54 { 55 gen_pool_free(coherent_pool, (unsigned long) vaddr, size); 56 } 57 58 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, 59 enum dma_data_direction dir) 60 { 61 void *addr = phys_to_virt(paddr); 62 63 switch (dir) { 64 case DMA_TO_DEVICE: 65 hexagon_clean_dcache_range((unsigned long) addr, 66 (unsigned long) addr + size); 67 break; 68 case DMA_FROM_DEVICE: 69 hexagon_inv_dcache_range((unsigned long) addr, 70 (unsigned long) addr + size); 71 break; 72 case DMA_BIDIRECTIONAL: 73 flush_dcache_range((unsigned long) addr, 74 (unsigned long) addr + size); 75 break; 76 default: 77 BUG(); 78 } 79 } 80