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}