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1/*
2 * Hi6220 stub clock driver
3 *
4 * Copyright (c) 2015 Hisilicon Limited.
5 * Copyright (c) 2015 Linaro Limited.
6 *
7 * Author: Leo Yan <leo.yan@linaro.org>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 */
14
15#include <linux/clk-provider.h>
16#include <linux/err.h>
17#include <linux/kernel.h>
18#include <linux/mfd/syscon.h>
19#include <linux/mailbox_client.h>
20#include <linux/of.h>
21#include <linux/of_device.h>
22#include <linux/regmap.h>
23
24/* Stub clocks id */
25#define HI6220_STUB_ACPU0 0
26#define HI6220_STUB_ACPU1 1
27#define HI6220_STUB_GPU 2
28#define HI6220_STUB_DDR 5
29
30/* Mailbox message */
31#define HI6220_MBOX_MSG_LEN 8
32
33#define HI6220_MBOX_FREQ 0xA
34#define HI6220_MBOX_CMD_SET 0x3
35#define HI6220_MBOX_OBJ_AP 0x0
36
37/* CPU dynamic frequency scaling */
38#define ACPU_DFS_FREQ_MAX 0x1724
39#define ACPU_DFS_CUR_FREQ 0x17CC
40#define ACPU_DFS_FLAG 0x1B30
41#define ACPU_DFS_FREQ_REQ 0x1B34
42#define ACPU_DFS_FREQ_LMT 0x1B38
43#define ACPU_DFS_LOCK_FLAG 0xAEAEAEAE
44
45#define to_stub_clk(hw) container_of(hw, struct hi6220_stub_clk, hw)
46
47struct hi6220_stub_clk {
48 u32 id;
49
50 struct device *dev;
51 struct clk_hw hw;
52
53 struct regmap *dfs_map;
54 struct mbox_client cl;
55 struct mbox_chan *mbox;
56};
57
58struct hi6220_mbox_msg {
59 unsigned char type;
60 unsigned char cmd;
61 unsigned char obj;
62 unsigned char src;
63 unsigned char para[4];
64};
65
66union hi6220_mbox_data {
67 unsigned int data[HI6220_MBOX_MSG_LEN];
68 struct hi6220_mbox_msg msg;
69};
70
71static unsigned int hi6220_acpu_get_freq(struct hi6220_stub_clk *stub_clk)
72{
73 unsigned int freq;
74
75 regmap_read(stub_clk->dfs_map, ACPU_DFS_CUR_FREQ, &freq);
76 return freq;
77}
78
79static int hi6220_acpu_set_freq(struct hi6220_stub_clk *stub_clk,
80 unsigned int freq)
81{
82 union hi6220_mbox_data data;
83
84 /* set the frequency in sram */
85 regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, freq);
86
87 /* compound mailbox message */
88 data.msg.type = HI6220_MBOX_FREQ;
89 data.msg.cmd = HI6220_MBOX_CMD_SET;
90 data.msg.obj = HI6220_MBOX_OBJ_AP;
91 data.msg.src = HI6220_MBOX_OBJ_AP;
92
93 mbox_send_message(stub_clk->mbox, &data);
94 return 0;
95}
96
97static int hi6220_acpu_round_freq(struct hi6220_stub_clk *stub_clk,
98 unsigned int freq)
99{
100 unsigned int limit_flag, limit_freq = UINT_MAX;
101 unsigned int max_freq;
102
103 /* check the constrained frequency */
104 regmap_read(stub_clk->dfs_map, ACPU_DFS_FLAG, &limit_flag);
105 if (limit_flag == ACPU_DFS_LOCK_FLAG)
106 regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, &limit_freq);
107
108 /* check the supported maximum frequency */
109 regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_MAX, &max_freq);
110
111 /* calculate the real maximum frequency */
112 max_freq = min(max_freq, limit_freq);
113
114 if (WARN_ON(freq > max_freq))
115 freq = max_freq;
116
117 return freq;
118}
119
120static unsigned long hi6220_stub_clk_recalc_rate(struct clk_hw *hw,
121 unsigned long parent_rate)
122{
123 u32 rate = 0;
124 struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
125
126 switch (stub_clk->id) {
127 case HI6220_STUB_ACPU0:
128 rate = hi6220_acpu_get_freq(stub_clk);
129
130 /* convert from kHz to Hz */
131 rate *= 1000;
132 break;
133
134 default:
135 dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
136 __func__, stub_clk->id);
137 break;
138 }
139
140 return rate;
141}
142
143static int hi6220_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
144 unsigned long parent_rate)
145{
146 struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
147 unsigned long new_rate = rate / 1000; /* kHz */
148 int ret = 0;
149
150 switch (stub_clk->id) {
151 case HI6220_STUB_ACPU0:
152 ret = hi6220_acpu_set_freq(stub_clk, new_rate);
153 if (ret < 0)
154 return ret;
155
156 break;
157
158 default:
159 dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
160 __func__, stub_clk->id);
161 break;
162 }
163
164 pr_debug("%s: set rate=%ldkHz\n", __func__, new_rate);
165 return ret;
166}
167
168static long hi6220_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
169 unsigned long *parent_rate)
170{
171 struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
172 unsigned long new_rate = rate / 1000; /* kHz */
173
174 switch (stub_clk->id) {
175 case HI6220_STUB_ACPU0:
176 new_rate = hi6220_acpu_round_freq(stub_clk, new_rate);
177
178 /* convert from kHz to Hz */
179 new_rate *= 1000;
180 break;
181
182 default:
183 dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
184 __func__, stub_clk->id);
185 break;
186 }
187
188 return new_rate;
189}
190
191static const struct clk_ops hi6220_stub_clk_ops = {
192 .recalc_rate = hi6220_stub_clk_recalc_rate,
193 .round_rate = hi6220_stub_clk_round_rate,
194 .set_rate = hi6220_stub_clk_set_rate,
195};
196
197static int hi6220_stub_clk_probe(struct platform_device *pdev)
198{
199 struct device *dev = &pdev->dev;
200 struct clk_init_data init;
201 struct hi6220_stub_clk *stub_clk;
202 struct clk *clk;
203 struct device_node *np = pdev->dev.of_node;
204 int ret;
205
206 stub_clk = devm_kzalloc(dev, sizeof(*stub_clk), GFP_KERNEL);
207 if (!stub_clk)
208 return -ENOMEM;
209
210 stub_clk->dfs_map = syscon_regmap_lookup_by_phandle(np,
211 "hisilicon,hi6220-clk-sram");
212 if (IS_ERR(stub_clk->dfs_map)) {
213 dev_err(dev, "failed to get sram regmap\n");
214 return PTR_ERR(stub_clk->dfs_map);
215 }
216
217 stub_clk->hw.init = &init;
218 stub_clk->dev = dev;
219 stub_clk->id = HI6220_STUB_ACPU0;
220
221 /* Use mailbox client with blocking mode */
222 stub_clk->cl.dev = dev;
223 stub_clk->cl.tx_done = NULL;
224 stub_clk->cl.tx_block = true;
225 stub_clk->cl.tx_tout = 500;
226 stub_clk->cl.knows_txdone = false;
227
228 /* Allocate mailbox channel */
229 stub_clk->mbox = mbox_request_channel(&stub_clk->cl, 0);
230 if (IS_ERR(stub_clk->mbox)) {
231 dev_err(dev, "failed get mailbox channel\n");
232 return PTR_ERR(stub_clk->mbox);
233 }
234
235 init.name = "acpu0";
236 init.ops = &hi6220_stub_clk_ops;
237 init.num_parents = 0;
238 init.flags = 0;
239
240 clk = devm_clk_register(dev, &stub_clk->hw);
241 if (IS_ERR(clk))
242 return PTR_ERR(clk);
243
244 ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
245 if (ret) {
246 dev_err(dev, "failed to register OF clock provider\n");
247 return ret;
248 }
249
250 /* initialize buffer to zero */
251 regmap_write(stub_clk->dfs_map, ACPU_DFS_FLAG, 0x0);
252 regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, 0x0);
253 regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, 0x0);
254
255 dev_dbg(dev, "Registered clock '%s'\n", init.name);
256 return 0;
257}
258
259static const struct of_device_id hi6220_stub_clk_of_match[] = {
260 { .compatible = "hisilicon,hi6220-stub-clk", },
261 {}
262};
263
264static struct platform_driver hi6220_stub_clk_driver = {
265 .driver = {
266 .name = "hi6220-stub-clk",
267 .of_match_table = hi6220_stub_clk_of_match,
268 },
269 .probe = hi6220_stub_clk_probe,
270};
271
272static int __init hi6220_stub_clk_init(void)
273{
274 return platform_driver_register(&hi6220_stub_clk_driver);
275}
276subsys_initcall(hi6220_stub_clk_init);
277

Warning: That file was not part of the compilation database. It may have many parsing errors.