summaryrefslogtreecommitdiff
path: root/drivers/dma/lpc18xx-dmamux.c
blob: 2b6436f4b193743dfd31341022b613712c9bf69b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
// SPDX-License-Identifier: GPL-2.0-only
/*
 * DMA Router driver for LPC18xx/43xx DMA MUX
 *
 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
 *
 * Based on TI DMA Crossbar driver by:
 *   Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
 *   Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
 */

#include <linux/err.h>
#include <linux/init.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/of_dma.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/spinlock.h>

/* CREG register offset and macros for mux manipulation */
#define LPC18XX_CREG_DMAMUX		0x11c
#define LPC18XX_DMAMUX_VAL(v, n)	((v) << (n * 2))
#define LPC18XX_DMAMUX_MASK(n)		(0x3 << (n * 2))
#define LPC18XX_DMAMUX_MAX_VAL		0x3

struct lpc18xx_dmamux {
	u32 value;
	bool busy;
};

struct lpc18xx_dmamux_data {
	struct dma_router dmarouter;
	struct lpc18xx_dmamux *muxes;
	u32 dma_master_requests;
	u32 dma_mux_requests;
	struct regmap *reg;
	spinlock_t lock;
};

static void lpc18xx_dmamux_free(struct device *dev, void *route_data)
{
	struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev);
	struct lpc18xx_dmamux *mux = route_data;
	unsigned long flags;

	spin_lock_irqsave(&dmamux->lock, flags);
	mux->busy = false;
	spin_unlock_irqrestore(&dmamux->lock, flags);
}

static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,
				    struct of_dma *ofdma)
{
	struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
	struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev);
	unsigned long flags;
	unsigned mux;

	if (dma_spec->args_count != 3) {
		dev_err(&pdev->dev, "invalid number of dma mux args\n");
		return ERR_PTR(-EINVAL);
	}

	mux = dma_spec->args[0];
	if (mux >= dmamux->dma_master_requests) {
		dev_err(&pdev->dev, "invalid mux number: %d\n",
			dma_spec->args[0]);
		return ERR_PTR(-EINVAL);
	}

	if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) {
		dev_err(&pdev->dev, "invalid dma mux value: %d\n",
			dma_spec->args[1]);
		return ERR_PTR(-EINVAL);
	}

	/* The of_node_put() will be done in the core for the node */
	dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
	if (!dma_spec->np) {
		dev_err(&pdev->dev, "can't get dma master\n");
		return ERR_PTR(-EINVAL);
	}

	spin_lock_irqsave(&dmamux->lock, flags);
	if (dmamux->muxes[mux].busy) {
		spin_unlock_irqrestore(&dmamux->lock, flags);
		dev_err(&pdev->dev, "dma request %u busy with %u.%u\n",
			mux, mux, dmamux->muxes[mux].value);
		of_node_put(dma_spec->np);
		return ERR_PTR(-EBUSY);
	}

	dmamux->muxes[mux].busy = true;
	dmamux->muxes[mux].value = dma_spec->args[1];

	regmap_update_bits(dmamux->reg, LPC18XX_CREG_DMAMUX,
			   LPC18XX_DMAMUX_MASK(mux),
			   LPC18XX_DMAMUX_VAL(dmamux->muxes[mux].value, mux));
	spin_unlock_irqrestore(&dmamux->lock, flags);

	dma_spec->args[1] = dma_spec->args[2];
	dma_spec->args_count = 2;

	dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux,
		dmamux->muxes[mux].value, mux);

	return &dmamux->muxes[mux];
}

static int lpc18xx_dmamux_probe(struct platform_device *pdev)
{
	struct device_node *dma_np, *np = pdev->dev.of_node;
	struct lpc18xx_dmamux_data *dmamux;
	int ret;

	dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
	if (!dmamux)
		return -ENOMEM;

	dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg");
	if (IS_ERR(dmamux->reg)) {
		dev_err(&pdev->dev, "syscon lookup failed\n");
		return PTR_ERR(dmamux->reg);
	}

	ret = of_property_read_u32(np, "dma-requests",
				   &dmamux->dma_mux_requests);
	if (ret) {
		dev_err(&pdev->dev, "missing dma-requests property\n");
		return ret;
	}

	dma_np = of_parse_phandle(np, "dma-masters", 0);
	if (!dma_np) {
		dev_err(&pdev->dev, "can't get dma master\n");
		return -ENODEV;
	}

	ret = of_property_read_u32(dma_np, "dma-requests",
				   &dmamux->dma_master_requests);
	of_node_put(dma_np);
	if (ret) {
		dev_err(&pdev->dev, "missing master dma-requests property\n");
		return ret;
	}

	dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests,
				     sizeof(struct lpc18xx_dmamux),
				     GFP_KERNEL);
	if (!dmamux->muxes)
		return -ENOMEM;

	spin_lock_init(&dmamux->lock);
	platform_set_drvdata(pdev, dmamux);
	dmamux->dmarouter.dev = &pdev->dev;
	dmamux->dmarouter.route_free = lpc18xx_dmamux_free;

	return of_dma_router_register(np, lpc18xx_dmamux_reserve,
				      &dmamux->dmarouter);
}

static const struct of_device_id lpc18xx_dmamux_match[] = {
	{ .compatible = "nxp,lpc1850-dmamux" },
	{},
};

static struct platform_driver lpc18xx_dmamux_driver = {
	.probe	= lpc18xx_dmamux_probe,
	.driver = {
		.name = "lpc18xx-dmamux",
		.of_match_table = lpc18xx_dmamux_match,
	},
};

static int __init lpc18xx_dmamux_init(void)
{
	return platform_driver_register(&lpc18xx_dmamux_driver);
}
arch_initcall(lpc18xx_dmamux_init);