1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * rcar-fcp.c -- R-Car Frame Compression Processor Driver
4 *
5 * Copyright (C) 2016 Renesas Electronics Corporation
6 *
7 * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
8 */
9
10 #include <linux/device.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/list.h>
13 #include <linux/module.h>
14 #include <linux/mod_devicetable.h>
15 #include <linux/mutex.h>
16 #include <linux/platform_device.h>
17 #include <linux/pm_runtime.h>
18 #include <linux/slab.h>
19
20 #include <media/rcar-fcp.h>
21
22 struct rcar_fcp_device {
23 struct list_head list;
24 struct device *dev;
25 };
26
27 static LIST_HEAD(fcp_devices);
28 static DEFINE_MUTEX(fcp_lock);
29
30 /* -----------------------------------------------------------------------------
31 * Public API
32 */
33
34 /**
35 * rcar_fcp_get - Find and acquire a reference to an FCP instance
36 * @np: Device node of the FCP instance
37 *
38 * Search the list of registered FCP instances for the instance corresponding to
39 * the given device node.
40 *
41 * Return a pointer to the FCP instance, or an ERR_PTR if the instance can't be
42 * found.
43 */
rcar_fcp_get(const struct device_node * np)44 struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np)
45 {
46 struct rcar_fcp_device *fcp;
47
48 mutex_lock(&fcp_lock);
49
50 list_for_each_entry(fcp, &fcp_devices, list) {
51 if (fcp->dev->of_node != np)
52 continue;
53
54 get_device(fcp->dev);
55 goto done;
56 }
57
58 fcp = ERR_PTR(-EPROBE_DEFER);
59
60 done:
61 mutex_unlock(&fcp_lock);
62 return fcp;
63 }
64 EXPORT_SYMBOL_GPL(rcar_fcp_get);
65
66 /**
67 * rcar_fcp_put - Release a reference to an FCP instance
68 * @fcp: The FCP instance
69 *
70 * Release the FCP instance acquired by a call to rcar_fcp_get().
71 */
rcar_fcp_put(struct rcar_fcp_device * fcp)72 void rcar_fcp_put(struct rcar_fcp_device *fcp)
73 {
74 if (fcp)
75 put_device(fcp->dev);
76 }
77 EXPORT_SYMBOL_GPL(rcar_fcp_put);
78
rcar_fcp_get_device(struct rcar_fcp_device * fcp)79 struct device *rcar_fcp_get_device(struct rcar_fcp_device *fcp)
80 {
81 return fcp->dev;
82 }
83 EXPORT_SYMBOL_GPL(rcar_fcp_get_device);
84
85 /**
86 * rcar_fcp_enable - Enable an FCP
87 * @fcp: The FCP instance
88 *
89 * Before any memory access through an FCP is performed by a module, the FCP
90 * must be enabled by a call to this function. The enable calls are reference
91 * counted, each successful call must be followed by one rcar_fcp_disable()
92 * call when no more memory transfer can occur through the FCP.
93 *
94 * Return 0 on success or a negative error code if an error occurs. The enable
95 * reference count isn't increased when this function returns an error.
96 */
rcar_fcp_enable(struct rcar_fcp_device * fcp)97 int rcar_fcp_enable(struct rcar_fcp_device *fcp)
98 {
99 if (!fcp)
100 return 0;
101
102 return pm_runtime_resume_and_get(fcp->dev);
103 }
104 EXPORT_SYMBOL_GPL(rcar_fcp_enable);
105
106 /**
107 * rcar_fcp_disable - Disable an FCP
108 * @fcp: The FCP instance
109 *
110 * This function is the counterpart of rcar_fcp_enable(). As enable calls are
111 * reference counted a disable call may not disable the FCP synchronously.
112 */
rcar_fcp_disable(struct rcar_fcp_device * fcp)113 void rcar_fcp_disable(struct rcar_fcp_device *fcp)
114 {
115 if (fcp)
116 pm_runtime_put(fcp->dev);
117 }
118 EXPORT_SYMBOL_GPL(rcar_fcp_disable);
119
120 /* -----------------------------------------------------------------------------
121 * Platform Driver
122 */
123
rcar_fcp_probe(struct platform_device * pdev)124 static int rcar_fcp_probe(struct platform_device *pdev)
125 {
126 struct rcar_fcp_device *fcp;
127
128 fcp = devm_kzalloc(&pdev->dev, sizeof(*fcp), GFP_KERNEL);
129 if (fcp == NULL)
130 return -ENOMEM;
131
132 fcp->dev = &pdev->dev;
133
134 dma_set_max_seg_size(fcp->dev, UINT_MAX);
135
136 pm_runtime_enable(&pdev->dev);
137
138 mutex_lock(&fcp_lock);
139 list_add_tail(&fcp->list, &fcp_devices);
140 mutex_unlock(&fcp_lock);
141
142 platform_set_drvdata(pdev, fcp);
143
144 return 0;
145 }
146
rcar_fcp_remove(struct platform_device * pdev)147 static void rcar_fcp_remove(struct platform_device *pdev)
148 {
149 struct rcar_fcp_device *fcp = platform_get_drvdata(pdev);
150
151 mutex_lock(&fcp_lock);
152 list_del(&fcp->list);
153 mutex_unlock(&fcp_lock);
154
155 pm_runtime_disable(&pdev->dev);
156 }
157
158 static const struct of_device_id rcar_fcp_of_match[] = {
159 { .compatible = "renesas,fcpf" },
160 { .compatible = "renesas,fcpv" },
161 { },
162 };
163 MODULE_DEVICE_TABLE(of, rcar_fcp_of_match);
164
165 static struct platform_driver rcar_fcp_platform_driver = {
166 .probe = rcar_fcp_probe,
167 .remove_new = rcar_fcp_remove,
168 .driver = {
169 .name = "rcar-fcp",
170 .of_match_table = rcar_fcp_of_match,
171 .suppress_bind_attrs = true,
172 },
173 };
174
175 module_platform_driver(rcar_fcp_platform_driver);
176
177 MODULE_ALIAS("rcar-fcp");
178 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
179 MODULE_DESCRIPTION("Renesas FCP Driver");
180 MODULE_LICENSE("GPL");
181
