1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Hisilicon clock driver
4 *
5 * Copyright (c) 2013-2017 Hisilicon Limited.
6 * Copyright (c) 2017 Linaro Limited.
7 *
8 * Author: Kai Zhao <zhaokai1@hisilicon.com>
9 *	    Tao Wang <kevin.wangtao@hisilicon.com>
10 *	    Leo Yan <leo.yan@linaro.org>
11 */
12
13#include <linux/clk-provider.h>
14#include <linux/device.h>
15#include <linux/err.h>
16#include <linux/init.h>
17#include <linux/io.h>
18#include <linux/mailbox_client.h>
19#include <linux/module.h>
20#include <linux/of.h>
21#include <linux/platform_device.h>
22#include <dt-bindings/clock/hi3660-clock.h>
23
24#define HI3660_STUB_CLOCK_DATA		(0x70)
25#define MHZ				(1000 * 1000)
26
27#define DEFINE_CLK_STUB(_id, _cmd, _name)			\
28	{							\
29		.id = (_id),					\
30		.cmd = (_cmd),					\
31		.hw.init = &(struct clk_init_data) {		\
32			.name = #_name,				\
33			.ops = &hi3660_stub_clk_ops,		\
34			.num_parents = 0,			\
35			.flags = CLK_GET_RATE_NOCACHE,		\
36		},						\
37	},
38
39#define to_stub_clk(_hw) container_of(_hw, struct hi3660_stub_clk, hw)
40
41struct hi3660_stub_clk_chan {
42	struct mbox_client cl;
43	struct mbox_chan *mbox;
44};
45
46struct hi3660_stub_clk {
47	unsigned int id;
48	struct clk_hw hw;
49	unsigned int cmd;
50	unsigned int msg[8];
51	unsigned int rate;
52};
53
54static void __iomem *freq_reg;
55static struct hi3660_stub_clk_chan stub_clk_chan;
56
57static unsigned long hi3660_stub_clk_recalc_rate(struct clk_hw *hw,
58						 unsigned long parent_rate)
59{
60	struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
61
62	/*
63	 * LPM3 writes back the CPU frequency in shared SRAM so read
64	 * back the frequency.
65	 */
66	stub_clk->rate = readl(freq_reg + (stub_clk->id << 2)) * MHZ;
67	return stub_clk->rate;
68}
69
70static long hi3660_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
71				       unsigned long *prate)
72{
73	/*
74	 * LPM3 handles rate rounding so just return whatever
75	 * rate is requested.
76	 */
77	return rate;
78}
79
80static int hi3660_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
81				    unsigned long parent_rate)
82{
83	struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
84
85	stub_clk->msg[0] = stub_clk->cmd;
86	stub_clk->msg[1] = rate / MHZ;
87
88	dev_dbg(stub_clk_chan.cl.dev, "set rate msg[0]=0x%x msg[1]=0x%x\n",
89		stub_clk->msg[0], stub_clk->msg[1]);
90
91	mbox_send_message(stub_clk_chan.mbox, stub_clk->msg);
92	mbox_client_txdone(stub_clk_chan.mbox, 0);
93
94	stub_clk->rate = rate;
95	return 0;
96}
97
98static const struct clk_ops hi3660_stub_clk_ops = {
99	.recalc_rate    = hi3660_stub_clk_recalc_rate,
100	.round_rate     = hi3660_stub_clk_round_rate,
101	.set_rate       = hi3660_stub_clk_set_rate,
102};
103
104static struct hi3660_stub_clk hi3660_stub_clks[HI3660_CLK_STUB_NUM] = {
105	DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER0, 0x0001030A, "cpu-cluster.0")
106	DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER1, 0x0002030A, "cpu-cluster.1")
107	DEFINE_CLK_STUB(HI3660_CLK_STUB_GPU, 0x0003030A, "clk-g3d")
108	DEFINE_CLK_STUB(HI3660_CLK_STUB_DDR, 0x00040309, "clk-ddrc")
109};
110
111static struct clk_hw *hi3660_stub_clk_hw_get(struct of_phandle_args *clkspec,
112					     void *data)
113{
114	unsigned int idx = clkspec->args[0];
115
116	if (idx >= HI3660_CLK_STUB_NUM) {
117		pr_err("%s: invalid index %u\n", __func__, idx);
118		return ERR_PTR(-EINVAL);
119	}
120
121	return &hi3660_stub_clks[idx].hw;
122}
123
124static int hi3660_stub_clk_probe(struct platform_device *pdev)
125{
126	struct device *dev = &pdev->dev;
127	struct resource *res;
128	unsigned int i;
129	int ret;
130
131	/* Use mailbox client without blocking */
132	stub_clk_chan.cl.dev = dev;
133	stub_clk_chan.cl.tx_done = NULL;
134	stub_clk_chan.cl.tx_block = false;
135	stub_clk_chan.cl.knows_txdone = false;
136
137	/* Allocate mailbox channel */
138	stub_clk_chan.mbox = mbox_request_channel(&stub_clk_chan.cl, 0);
139	if (IS_ERR(stub_clk_chan.mbox))
140		return PTR_ERR(stub_clk_chan.mbox);
141
142	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
143	if (!res)
144		return -EINVAL;
145	freq_reg = devm_ioremap(dev, res->start, resource_size(res));
146	if (!freq_reg)
147		return -ENOMEM;
148
149	freq_reg += HI3660_STUB_CLOCK_DATA;
150
151	for (i = 0; i < HI3660_CLK_STUB_NUM; i++) {
152		ret = devm_clk_hw_register(&pdev->dev, &hi3660_stub_clks[i].hw);
153		if (ret)
154			return ret;
155	}
156
157	return devm_of_clk_add_hw_provider(&pdev->dev, hi3660_stub_clk_hw_get,
158					   hi3660_stub_clks);
159}
160
161static const struct of_device_id hi3660_stub_clk_of_match[] = {
162	{ .compatible = "hisilicon,hi3660-stub-clk", },
163	{}
164};
165
166static struct platform_driver hi3660_stub_clk_driver = {
167	.probe	= hi3660_stub_clk_probe,
168	.driver = {
169		.name = "hi3660-stub-clk",
170		.of_match_table = hi3660_stub_clk_of_match,
171	},
172};
173
174static int __init hi3660_stub_clk_init(void)
175{
176	return platform_driver_register(&hi3660_stub_clk_driver);
177}
178subsys_initcall(hi3660_stub_clk_init);
179