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
22struct rcar_fcp_device {
23	struct list_head list;
24	struct device *dev;
25};
26
27static LIST_HEAD(fcp_devices);
28static 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 */
44struct 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
60done:
61	mutex_unlock(&fcp_lock);
62	return fcp;
63}
64EXPORT_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 */
72void rcar_fcp_put(struct rcar_fcp_device *fcp)
73{
74	if (fcp)
75		put_device(fcp->dev);
76}
77EXPORT_SYMBOL_GPL(rcar_fcp_put);
78
79struct device *rcar_fcp_get_device(struct rcar_fcp_device *fcp)
80{
81	return fcp->dev;
82}
83EXPORT_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 */
97int rcar_fcp_enable(struct rcar_fcp_device *fcp)
98{
99	int ret;
100
101	if (!fcp)
102		return 0;
103
104	ret = pm_runtime_get_sync(fcp->dev);
105	if (ret < 0) {
106		pm_runtime_put_noidle(fcp->dev);
107		return ret;
108	}
109
110	return 0;
111}
112EXPORT_SYMBOL_GPL(rcar_fcp_enable);
113
114/**
115 * rcar_fcp_disable - Disable an FCP
116 * @fcp: The FCP instance
117 *
118 * This function is the counterpart of rcar_fcp_enable(). As enable calls are
119 * reference counted a disable call may not disable the FCP synchronously.
120 */
121void rcar_fcp_disable(struct rcar_fcp_device *fcp)
122{
123	if (fcp)
124		pm_runtime_put(fcp->dev);
125}
126EXPORT_SYMBOL_GPL(rcar_fcp_disable);
127
128/* -----------------------------------------------------------------------------
129 * Platform Driver
130 */
131
132static int rcar_fcp_probe(struct platform_device *pdev)
133{
134	struct rcar_fcp_device *fcp;
135
136	fcp = devm_kzalloc(&pdev->dev, sizeof(*fcp), GFP_KERNEL);
137	if (fcp == NULL)
138		return -ENOMEM;
139
140	fcp->dev = &pdev->dev;
141
142	dma_set_max_seg_size(fcp->dev, UINT_MAX);
143
144	pm_runtime_enable(&pdev->dev);
145
146	mutex_lock(&fcp_lock);
147	list_add_tail(&fcp->list, &fcp_devices);
148	mutex_unlock(&fcp_lock);
149
150	platform_set_drvdata(pdev, fcp);
151
152	return 0;
153}
154
155static int rcar_fcp_remove(struct platform_device *pdev)
156{
157	struct rcar_fcp_device *fcp = platform_get_drvdata(pdev);
158
159	mutex_lock(&fcp_lock);
160	list_del(&fcp->list);
161	mutex_unlock(&fcp_lock);
162
163	pm_runtime_disable(&pdev->dev);
164
165	return 0;
166}
167
168static const struct of_device_id rcar_fcp_of_match[] = {
169	{ .compatible = "renesas,fcpf" },
170	{ .compatible = "renesas,fcpv" },
171	{ },
172};
173MODULE_DEVICE_TABLE(of, rcar_fcp_of_match);
174
175static struct platform_driver rcar_fcp_platform_driver = {
176	.probe		= rcar_fcp_probe,
177	.remove		= rcar_fcp_remove,
178	.driver		= {
179		.name	= "rcar-fcp",
180		.of_match_table = rcar_fcp_of_match,
181		.suppress_bind_attrs = true,
182	},
183};
184
185module_platform_driver(rcar_fcp_platform_driver);
186
187MODULE_ALIAS("rcar-fcp");
188MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
189MODULE_DESCRIPTION("Renesas FCP Driver");
190MODULE_LICENSE("GPL");
191