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12#include <linux/err.h>
13#include <linux/init.h>
14#include <linux/mfd/syscon.h>
15#include <linux/of_device.h>
16#include <linux/of_dma.h>
17#include <linux/regmap.h>
18#include <linux/spinlock.h>
19
20
21#define LPC18XX_CREG_DMAMUX 0x11c
22#define LPC18XX_DMAMUX_VAL(v, n) ((v) << (n * 2))
23#define LPC18XX_DMAMUX_MASK(n) (0x3 << (n * 2))
24#define LPC18XX_DMAMUX_MAX_VAL 0x3
25
26struct lpc18xx_dmamux {
27 u32 value;
28 bool busy;
29};
30
31struct lpc18xx_dmamux_data {
32 struct dma_router dmarouter;
33 struct lpc18xx_dmamux *muxes;
34 u32 dma_master_requests;
35 u32 dma_mux_requests;
36 struct regmap *reg;
37 spinlock_t lock;
38};
39
40static void lpc18xx_dmamux_free(struct device *dev, void *route_data)
41{
42 struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev);
43 struct lpc18xx_dmamux *mux = route_data;
44 unsigned long flags;
45
46 spin_lock_irqsave(&dmamux->lock, flags);
47 mux->busy = false;
48 spin_unlock_irqrestore(&dmamux->lock, flags);
49}
50
51static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,
52 struct of_dma *ofdma)
53{
54 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
55 struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev);
56 unsigned long flags;
57 unsigned mux;
58
59 if (dma_spec->args_count != 3) {
60 dev_err(&pdev->dev, "invalid number of dma mux args\n");
61 return ERR_PTR(-EINVAL);
62 }
63
64 mux = dma_spec->args[0];
65 if (mux >= dmamux->dma_master_requests) {
66 dev_err(&pdev->dev, "invalid mux number: %d\n",
67 dma_spec->args[0]);
68 return ERR_PTR(-EINVAL);
69 }
70
71 if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) {
72 dev_err(&pdev->dev, "invalid dma mux value: %d\n",
73 dma_spec->args[1]);
74 return ERR_PTR(-EINVAL);
75 }
76
77
78 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
79 if (!dma_spec->np) {
80 dev_err(&pdev->dev, "can't get dma master\n");
81 return ERR_PTR(-EINVAL);
82 }
83
84 spin_lock_irqsave(&dmamux->lock, flags);
85 if (dmamux->muxes[mux].busy) {
86 spin_unlock_irqrestore(&dmamux->lock, flags);
87 dev_err(&pdev->dev, "dma request %u busy with %u.%u\n",
88 mux, mux, dmamux->muxes[mux].value);
89 of_node_put(dma_spec->np);
90 return ERR_PTR(-EBUSY);
91 }
92
93 dmamux->muxes[mux].busy = true;
94 dmamux->muxes[mux].value = dma_spec->args[1];
95
96 regmap_update_bits(dmamux->reg, LPC18XX_CREG_DMAMUX,
97 LPC18XX_DMAMUX_MASK(mux),
98 LPC18XX_DMAMUX_VAL(dmamux->muxes[mux].value, mux));
99 spin_unlock_irqrestore(&dmamux->lock, flags);
100
101 dma_spec->args[1] = dma_spec->args[2];
102 dma_spec->args_count = 2;
103
104 dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux,
105 dmamux->muxes[mux].value, mux);
106
107 return &dmamux->muxes[mux];
108}
109
110static int lpc18xx_dmamux_probe(struct platform_device *pdev)
111{
112 struct device_node *dma_np, *np = pdev->dev.of_node;
113 struct lpc18xx_dmamux_data *dmamux;
114 int ret;
115
116 dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
117 if (!dmamux)
118 return -ENOMEM;
119
120 dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg");
121 if (IS_ERR(dmamux->reg)) {
122 dev_err(&pdev->dev, "syscon lookup failed\n");
123 return PTR_ERR(dmamux->reg);
124 }
125
126 ret = of_property_read_u32(np, "dma-requests",
127 &dmamux->dma_mux_requests);
128 if (ret) {
129 dev_err(&pdev->dev, "missing dma-requests property\n");
130 return ret;
131 }
132
133 dma_np = of_parse_phandle(np, "dma-masters", 0);
134 if (!dma_np) {
135 dev_err(&pdev->dev, "can't get dma master\n");
136 return -ENODEV;
137 }
138
139 ret = of_property_read_u32(dma_np, "dma-requests",
140 &dmamux->dma_master_requests);
141 of_node_put(dma_np);
142 if (ret) {
143 dev_err(&pdev->dev, "missing master dma-requests property\n");
144 return ret;
145 }
146
147 dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests,
148 sizeof(struct lpc18xx_dmamux),
149 GFP_KERNEL);
150 if (!dmamux->muxes)
151 return -ENOMEM;
152
153 spin_lock_init(&dmamux->lock);
154 platform_set_drvdata(pdev, dmamux);
155 dmamux->dmarouter.dev = &pdev->dev;
156 dmamux->dmarouter.route_free = lpc18xx_dmamux_free;
157
158 return of_dma_router_register(np, lpc18xx_dmamux_reserve,
159 &dmamux->dmarouter);
160}
161
162static const struct of_device_id lpc18xx_dmamux_match[] = {
163 { .compatible = "nxp,lpc1850-dmamux" },
164 {},
165};
166
167static struct platform_driver lpc18xx_dmamux_driver = {
168 .probe = lpc18xx_dmamux_probe,
169 .driver = {
170 .name = "lpc18xx-dmamux",
171 .of_match_table = lpc18xx_dmamux_match,
172 },
173};
174
175static int __init lpc18xx_dmamux_init(void)
176{
177 return platform_driver_register(&lpc18xx_dmamux_driver);
178}
179arch_initcall(lpc18xx_dmamux_init);
180
