GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / dma / lpc18xx-dmamux.c
1 // SPDX-License-Identifier: GPL-2.0-only
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>
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);