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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
e5f4ae84 JE |
2 | /* |
3 | * DMA Router driver for LPC18xx/43xx DMA MUX | |
4 | * | |
5 | * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com> | |
6 | * | |
7 | * Based on TI DMA Crossbar driver by: | |
8 | * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com | |
9 | * Author: Peter Ujfalusi <peter.ujfalusi@ti.com> | |
e5f4ae84 JE |
10 | */ |
11 | ||
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 | /* CREG register offset and macros for mux manipulation */ | |
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 | ||
26 | struct lpc18xx_dmamux { | |
27 | u32 value; | |
28 | bool busy; | |
29 | }; | |
30 | ||
31 | struct 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 | ||
40 | static 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 | ||
51 | static 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 | /* The of_node_put() will be done in the core for the node */ | |
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 | ||
110 | static 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 | ||
162 | static const struct of_device_id lpc18xx_dmamux_match[] = { | |
163 | { .compatible = "nxp,lpc1850-dmamux" }, | |
164 | {}, | |
165 | }; | |
166 | ||
167 | static 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 | ||
175 | static int __init lpc18xx_dmamux_init(void) | |
176 | { | |
177 | return platform_driver_register(&lpc18xx_dmamux_driver); | |
178 | } | |
179 | arch_initcall(lpc18xx_dmamux_init); |