LXR linux/arch/hexagon/kernel/dma.c

   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
  14static struct gen_pool *coherent_pool;
  15
  16
  17/* Allocates from a pool of uncached memory that was reserved at boot time */
  18
  19void *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
  52void 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
  58void 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