1 // SPDX-License-Identifier: GPL-2.0-only
2 //
3 // Copyright 2024 Timesys Corporation <piotr.wojtaszczyk@timesys.com>
4 //
5 // Based on TI DMA Crossbar driver by:
6 // Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
7 // Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
8
9 #include <linux/err.h>
10 #include <linux/init.h>
11 #include <linux/mfd/syscon.h>
12 #include <linux/of.h>
13 #include <linux/of_dma.h>
14 #include <linux/of_platform.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17 #include <linux/spinlock.h>
18
19 #define LPC32XX_SSP_CLK_CTRL 0x78
20 #define LPC32XX_I2S_CLK_CTRL 0x7c
21
22 struct lpc32xx_dmamux {
23 int signal;
24 char *name_sel0;
25 char *name_sel1;
26 int muxval;
27 int muxreg;
28 int bit;
29 bool busy;
30 };
31
32 struct lpc32xx_dmamux_data {
33 struct dma_router dmarouter;
34 struct regmap *reg;
35 spinlock_t lock; /* protects busy status flag */
36 };
37
38 /* From LPC32x0 User manual "3.2.1 DMA request signals" */
39 static struct lpc32xx_dmamux lpc32xx_muxes[] = {
40 {
41 .signal = 3,
42 .name_sel0 = "spi2-rx-tx",
43 .name_sel1 = "ssp1-rx",
44 .muxreg = LPC32XX_SSP_CLK_CTRL,
45 .bit = 5,
46 },
47 {
48 .signal = 10,
49 .name_sel0 = "uart7-rx",
50 .name_sel1 = "i2s1-dma1",
51 .muxreg = LPC32XX_I2S_CLK_CTRL,
52 .bit = 4,
53 },
54 {
55 .signal = 11,
56 .name_sel0 = "spi1-rx-tx",
57 .name_sel1 = "ssp1-tx",
58 .muxreg = LPC32XX_SSP_CLK_CTRL,
59 .bit = 4,
60 },
61 {
62 .signal = 14,
63 .name_sel0 = "none",
64 .name_sel1 = "ssp0-rx",
65 .muxreg = LPC32XX_SSP_CLK_CTRL,
66 .bit = 3,
67 },
68 {
69 .signal = 15,
70 .name_sel0 = "none",
71 .name_sel1 = "ssp0-tx",
72 .muxreg = LPC32XX_SSP_CLK_CTRL,
73 .bit = 2,
74 },
75 };
76
lpc32xx_dmamux_release(struct device * dev,void * route_data)77 static void lpc32xx_dmamux_release(struct device *dev, void *route_data)
78 {
79 struct lpc32xx_dmamux_data *dmamux = dev_get_drvdata(dev);
80 struct lpc32xx_dmamux *mux = route_data;
81
82 dev_dbg(dev, "releasing dma request signal %d routed to %s\n",
83 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
84
85 guard(spinlock)(&dmamux->lock);
86
87 mux->busy = false;
88 }
89
lpc32xx_dmamux_reserve(struct of_phandle_args * dma_spec,struct of_dma * ofdma)90 static void *lpc32xx_dmamux_reserve(struct of_phandle_args *dma_spec,
91 struct of_dma *ofdma)
92 {
93 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
94 struct device *dev = &pdev->dev;
95 struct lpc32xx_dmamux_data *dmamux = platform_get_drvdata(pdev);
96 unsigned long flags;
97 struct lpc32xx_dmamux *mux = NULL;
98 int i;
99
100 if (dma_spec->args_count != 3) {
101 dev_err(&pdev->dev, "invalid number of dma mux args\n");
102 return ERR_PTR(-EINVAL);
103 }
104
105 for (i = 0; i < ARRAY_SIZE(lpc32xx_muxes); i++) {
106 if (lpc32xx_muxes[i].signal == dma_spec->args[0]) {
107 mux = &lpc32xx_muxes[i];
108 break;
109 }
110 }
111 if (!mux) {
112 dev_err(&pdev->dev, "invalid mux request number: %d\n",
113 dma_spec->args[0]);
114 return ERR_PTR(-EINVAL);
115 }
116
117 if (dma_spec->args[2] > 1) {
118 dev_err(&pdev->dev, "invalid dma mux value: %d\n",
119 dma_spec->args[1]);
120 return ERR_PTR(-EINVAL);
121 }
122
123 /* The of_node_put() will be done in the core for the node */
124 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
125 if (!dma_spec->np) {
126 dev_err(&pdev->dev, "can't get dma master\n");
127 return ERR_PTR(-EINVAL);
128 }
129
130 spin_lock_irqsave(&dmamux->lock, flags);
131 if (mux->busy) {
132 spin_unlock_irqrestore(&dmamux->lock, flags);
133 dev_err(dev, "dma request signal %d busy, routed to %s\n",
134 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
135 of_node_put(dma_spec->np);
136 return ERR_PTR(-EBUSY);
137 }
138
139 mux->busy = true;
140 mux->muxval = dma_spec->args[2] ? BIT(mux->bit) : 0;
141
142 regmap_update_bits(dmamux->reg, mux->muxreg, BIT(mux->bit), mux->muxval);
143 spin_unlock_irqrestore(&dmamux->lock, flags);
144
145 dma_spec->args[2] = 0;
146 dma_spec->args_count = 2;
147
148 dev_dbg(dev, "dma request signal %d routed to %s\n",
149 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
150
151 return mux;
152 }
153
lpc32xx_dmamux_probe(struct platform_device * pdev)154 static int lpc32xx_dmamux_probe(struct platform_device *pdev)
155 {
156 struct device_node *np = pdev->dev.of_node;
157 struct lpc32xx_dmamux_data *dmamux;
158
159 dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
160 if (!dmamux)
161 return -ENOMEM;
162
163 dmamux->reg = syscon_node_to_regmap(np->parent);
164 if (IS_ERR(dmamux->reg)) {
165 dev_err(&pdev->dev, "syscon lookup failed\n");
166 return PTR_ERR(dmamux->reg);
167 }
168
169 spin_lock_init(&dmamux->lock);
170 platform_set_drvdata(pdev, dmamux);
171 dmamux->dmarouter.dev = &pdev->dev;
172 dmamux->dmarouter.route_free = lpc32xx_dmamux_release;
173
174 return of_dma_router_register(np, lpc32xx_dmamux_reserve,
175 &dmamux->dmarouter);
176 }
177
178 static const struct of_device_id lpc32xx_dmamux_match[] = {
179 { .compatible = "nxp,lpc3220-dmamux" },
180 {},
181 };
182
183 static struct platform_driver lpc32xx_dmamux_driver = {
184 .probe = lpc32xx_dmamux_probe,
185 .driver = {
186 .name = "lpc32xx-dmamux",
187 .of_match_table = lpc32xx_dmamux_match,
188 },
189 };
190
lpc32xx_dmamux_init(void)191 static int __init lpc32xx_dmamux_init(void)
192 {
193 return platform_driver_register(&lpc32xx_dmamux_driver);
194 }
195 arch_initcall(lpc32xx_dmamux_init);
196