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

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
   4 */
   5#include <linux/init.h>
   6#include <linux/dma-direct.h>
   7#include <linux/dma-mapping.h>
   8#include <linux/dma-map-ops.h>
   9#include <linux/swiotlb.h>
  10
  11#include <asm/bootinfo.h>
  12#include <asm/dma.h>
  13#include <asm/loongson.h>
  14
  15/*
  16 * We extract 4bit node id (bit 44~47) from Loongson-3's
  17 * 48bit physical address space and embed it into 40bit.
  18 */
  19
  20static int node_id_offset;
  21
  22dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
  23{
  24        long nid = (paddr >> 44) & 0xf;
  25
  26        return ((nid << 44) ^ paddr) | (nid << node_id_offset);
  27}
  28
  29phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
  30{
  31        long nid = (daddr >> node_id_offset) & 0xf;
  32
  33        return ((nid << node_id_offset) ^ daddr) | (nid << 44);
  34}
  35
  36void __init plat_swiotlb_setup(void)
  37{
  38        swiotlb_init(true, SWIOTLB_VERBOSE);
  39        node_id_offset = ((readl(LS7A_DMA_CFG) & LS7A_DMA_NODE_MASK) >> LS7A_DMA_NODE_SHF) + 36;
  40}
  41