LXR linux/drivers/dma/dw/of.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Platform driver for the Synopsys DesignWare DMA Controller
   4 *
   5 * Copyright (C) 2007-2008 Atmel Corporation
   6 * Copyright (C) 2010-2011 ST Microelectronics
   7 * Copyright (C) 2013 Intel Corporation
   8 */
   9
  10#include <linux/of.h>
  11#include <linux/of_dma.h>
  12#include <linux/platform_device.h>
  13
  14#include "internal.h"
  15
  16static struct dma_chan *dw_dma_of_xlate(struct of_phandle_args *dma_spec,
  17                                        struct of_dma *ofdma)
  18{
  19        struct dw_dma *dw = ofdma->of_dma_data;
  20        struct dw_dma_slave slave = {
  21                .dma_dev = dw->dma.dev,
  22        };
  23        dma_cap_mask_t cap;
  24
  25        if (dma_spec->args_count < 3 || dma_spec->args_count > 4)
  26                return NULL;
  27
  28        slave.src_id = dma_spec->args[0];
  29        slave.dst_id = dma_spec->args[0];
  30        slave.m_master = dma_spec->args[1];
  31        slave.p_master = dma_spec->args[2];
  32        if (dma_spec->args_count >= 4)
  33                slave.channels = dma_spec->args[3];
  34
  35        if (WARN_ON(slave.src_id >= DW_DMA_MAX_NR_REQUESTS ||
  36                    slave.dst_id >= DW_DMA_MAX_NR_REQUESTS ||
  37                    slave.m_master >= dw->pdata->nr_masters ||
  38                    slave.p_master >= dw->pdata->nr_masters ||
  39                    slave.channels >= BIT(dw->pdata->nr_channels)))
  40                return NULL;
  41
  42        dma_cap_zero(cap);
  43        dma_cap_set(DMA_SLAVE, cap);
  44
  45        /* TODO: there should be a simpler way to do this */
  46        return dma_request_channel(cap, dw_dma_filter, &slave);
  47}
  48
  49struct dw_dma_platform_data *dw_dma_parse_dt(struct platform_device *pdev)
  50{
  51        struct device_node *np = pdev->dev.of_node;
  52        struct dw_dma_platform_data *pdata;
  53        u32 tmp, arr[DW_DMA_MAX_NR_MASTERS];
  54        u32 nr_masters;
  55        u32 nr_channels;
  56
  57        if (of_property_read_u32(np, "dma-masters", &nr_masters))
  58                return NULL;
  59        if (nr_masters < 1 || nr_masters > DW_DMA_MAX_NR_MASTERS)
  60                return NULL;
  61
  62        if (of_property_read_u32(np, "dma-channels", &nr_channels))
  63                return NULL;
  64        if (nr_channels > DW_DMA_MAX_NR_CHANNELS)
  65                return NULL;
  66
  67        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  68        if (!pdata)
  69                return NULL;
  70
  71        pdata->nr_masters = nr_masters;
  72        pdata->nr_channels = nr_channels;
  73
  74        of_property_read_u32(np, "chan_allocation_order", &pdata->chan_allocation_order);
  75        of_property_read_u32(np, "chan_priority", &pdata->chan_priority);
  76
  77        of_property_read_u32(np, "block_size", &pdata->block_size);
  78
  79        /* Try deprecated property first */
  80        if (!of_property_read_u32_array(np, "data_width", arr, nr_masters)) {
  81                for (tmp = 0; tmp < nr_masters; tmp++)
  82                        pdata->data_width[tmp] = BIT(arr[tmp] & 0x07);
  83        }
  84
  85        /* If "data_width" and "data-width" both provided use the latter one */
  86        of_property_read_u32_array(np, "data-width", pdata->data_width, nr_masters);
  87
  88        memset32(pdata->multi_block, 1, nr_channels);
  89        of_property_read_u32_array(np, "multi-block", pdata->multi_block, nr_channels);
  90
  91        memset32(pdata->max_burst, DW_DMA_MAX_BURST, nr_channels);
  92        of_property_read_u32_array(np, "snps,max-burst-len", pdata->max_burst, nr_channels);
  93
  94        of_property_read_u32(np, "snps,dma-protection-control", &pdata->protctl);
  95        if (pdata->protctl > CHAN_PROTCTL_MASK)
  96                return NULL;
  97
  98        return pdata;
  99}
 100
 101void dw_dma_of_controller_register(struct dw_dma *dw)
 102{
 103        struct device *dev = dw->dma.dev;
 104        int ret;
 105
 106        if (!dev->of_node)
 107                return;
 108
 109        ret = of_dma_controller_register(dev->of_node, dw_dma_of_xlate, dw);
 110        if (ret)
 111                dev_err(dev, "could not register of_dma_controller\n");
 112}
 113
 114void dw_dma_of_controller_free(struct dw_dma *dw)
 115{
 116        struct device *dev = dw->dma.dev;
 117
 118        if (!dev->of_node)
 119                return;
 120
 121        of_dma_controller_free(dev->of_node);
 122}
 123