1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Hi6220 stub clock driver
4 *
5 * Copyright (c) 2015 Hisilicon Limited.
6 * Copyright (c) 2015 Linaro Limited.
7 *
8 * Author: Leo Yan <leo.yan@linaro.org>
9 */
10
11 #include <linux/clk-provider.h>
12 #include <linux/err.h>
13 #include <linux/kernel.h>
14 #include <linux/mfd/syscon.h>
15 #include <linux/mailbox_client.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/regmap.h>
19
20 /* Stub clocks id */
21 #define HI6220_STUB_ACPU0 0
22 #define HI6220_STUB_ACPU1 1
23 #define HI6220_STUB_GPU 2
24 #define HI6220_STUB_DDR 5
25
26 /* Mailbox message */
27 #define HI6220_MBOX_MSG_LEN 8
28
29 #define HI6220_MBOX_FREQ 0xA
30 #define HI6220_MBOX_CMD_SET 0x3
31 #define HI6220_MBOX_OBJ_AP 0x0
32
33 /* CPU dynamic frequency scaling */
34 #define ACPU_DFS_FREQ_MAX 0x1724
35 #define ACPU_DFS_CUR_FREQ 0x17CC
36 #define ACPU_DFS_FLAG 0x1B30
37 #define ACPU_DFS_FREQ_REQ 0x1B34
38 #define ACPU_DFS_FREQ_LMT 0x1B38
39 #define ACPU_DFS_LOCK_FLAG 0xAEAEAEAE
40
41 #define to_stub_clk(hw) container_of(hw, struct hi6220_stub_clk, hw)
42
43 struct hi6220_stub_clk {
44 u32 id;
45
46 struct device *dev;
47 struct clk_hw hw;
48
49 struct regmap *dfs_map;
50 struct mbox_client cl;
51 struct mbox_chan *mbox;
52 };
53
54 struct hi6220_mbox_msg {
55 unsigned char type;
56 unsigned char cmd;
57 unsigned char obj;
58 unsigned char src;
59 unsigned char para[4];
60 };
61
62 union hi6220_mbox_data {
63 unsigned int data[HI6220_MBOX_MSG_LEN];
64 struct hi6220_mbox_msg msg;
65 };
66
hi6220_acpu_get_freq(struct hi6220_stub_clk * stub_clk)67 static unsigned int hi6220_acpu_get_freq(struct hi6220_stub_clk *stub_clk)
68 {
69 unsigned int freq;
70
71 regmap_read(stub_clk->dfs_map, ACPU_DFS_CUR_FREQ, &freq);
72 return freq;
73 }
74
hi6220_acpu_set_freq(struct hi6220_stub_clk * stub_clk,unsigned int freq)75 static int hi6220_acpu_set_freq(struct hi6220_stub_clk *stub_clk,
76 unsigned int freq)
77 {
78 union hi6220_mbox_data data;
79
80 /* set the frequency in sram */
81 regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, freq);
82
83 /* compound mailbox message */
84 data.msg.type = HI6220_MBOX_FREQ;
85 data.msg.cmd = HI6220_MBOX_CMD_SET;
86 data.msg.obj = HI6220_MBOX_OBJ_AP;
87 data.msg.src = HI6220_MBOX_OBJ_AP;
88
89 mbox_send_message(stub_clk->mbox, &data);
90 return 0;
91 }
92
hi6220_acpu_round_freq(struct hi6220_stub_clk * stub_clk,unsigned int freq)93 static int hi6220_acpu_round_freq(struct hi6220_stub_clk *stub_clk,
94 unsigned int freq)
95 {
96 unsigned int limit_flag, limit_freq = UINT_MAX;
97 unsigned int max_freq;
98
99 /* check the constrained frequency */
100 regmap_read(stub_clk->dfs_map, ACPU_DFS_FLAG, &limit_flag);
101 if (limit_flag == ACPU_DFS_LOCK_FLAG)
102 regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, &limit_freq);
103
104 /* check the supported maximum frequency */
105 regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_MAX, &max_freq);
106
107 /* calculate the real maximum frequency */
108 max_freq = min(max_freq, limit_freq);
109
110 if (WARN_ON(freq > max_freq))
111 freq = max_freq;
112
113 return freq;
114 }
115
hi6220_stub_clk_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)116 static unsigned long hi6220_stub_clk_recalc_rate(struct clk_hw *hw,
117 unsigned long parent_rate)
118 {
119 u32 rate = 0;
120 struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
121
122 switch (stub_clk->id) {
123 case HI6220_STUB_ACPU0:
124 rate = hi6220_acpu_get_freq(stub_clk);
125
126 /* convert from kHz to Hz */
127 rate *= 1000;
128 break;
129
130 default:
131 dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
132 __func__, stub_clk->id);
133 break;
134 }
135
136 return rate;
137 }
138
hi6220_stub_clk_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)139 static int hi6220_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
140 unsigned long parent_rate)
141 {
142 struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
143 unsigned long new_rate = rate / 1000; /* kHz */
144 int ret = 0;
145
146 switch (stub_clk->id) {
147 case HI6220_STUB_ACPU0:
148 ret = hi6220_acpu_set_freq(stub_clk, new_rate);
149 if (ret < 0)
150 return ret;
151
152 break;
153
154 default:
155 dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
156 __func__, stub_clk->id);
157 break;
158 }
159
160 pr_debug("%s: set rate=%ldkHz\n", __func__, new_rate);
161 return ret;
162 }
163
hi6220_stub_clk_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent_rate)164 static long hi6220_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
165 unsigned long *parent_rate)
166 {
167 struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
168 unsigned long new_rate = rate / 1000; /* kHz */
169
170 switch (stub_clk->id) {
171 case HI6220_STUB_ACPU0:
172 new_rate = hi6220_acpu_round_freq(stub_clk, new_rate);
173
174 /* convert from kHz to Hz */
175 new_rate *= 1000;
176 break;
177
178 default:
179 dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
180 __func__, stub_clk->id);
181 break;
182 }
183
184 return new_rate;
185 }
186
187 static const struct clk_ops hi6220_stub_clk_ops = {
188 .recalc_rate = hi6220_stub_clk_recalc_rate,
189 .round_rate = hi6220_stub_clk_round_rate,
190 .set_rate = hi6220_stub_clk_set_rate,
191 };
192
hi6220_stub_clk_probe(struct platform_device * pdev)193 static int hi6220_stub_clk_probe(struct platform_device *pdev)
194 {
195 struct device *dev = &pdev->dev;
196 struct clk_init_data init;
197 struct hi6220_stub_clk *stub_clk;
198 struct clk *clk;
199 struct device_node *np = pdev->dev.of_node;
200 int ret;
201
202 stub_clk = devm_kzalloc(dev, sizeof(*stub_clk), GFP_KERNEL);
203 if (!stub_clk)
204 return -ENOMEM;
205
206 stub_clk->dfs_map = syscon_regmap_lookup_by_phandle(np,
207 "hisilicon,hi6220-clk-sram");
208 if (IS_ERR(stub_clk->dfs_map)) {
209 dev_err(dev, "failed to get sram regmap\n");
210 return PTR_ERR(stub_clk->dfs_map);
211 }
212
213 stub_clk->hw.init = &init;
214 stub_clk->dev = dev;
215 stub_clk->id = HI6220_STUB_ACPU0;
216
217 /* Use mailbox client with blocking mode */
218 stub_clk->cl.dev = dev;
219 stub_clk->cl.tx_done = NULL;
220 stub_clk->cl.tx_block = true;
221 stub_clk->cl.tx_tout = 500;
222 stub_clk->cl.knows_txdone = false;
223
224 /* Allocate mailbox channel */
225 stub_clk->mbox = mbox_request_channel(&stub_clk->cl, 0);
226 if (IS_ERR(stub_clk->mbox)) {
227 dev_err(dev, "failed get mailbox channel\n");
228 return PTR_ERR(stub_clk->mbox);
229 }
230
231 init.name = "acpu0";
232 init.ops = &hi6220_stub_clk_ops;
233 init.num_parents = 0;
234 init.flags = 0;
235
236 clk = devm_clk_register(dev, &stub_clk->hw);
237 if (IS_ERR(clk))
238 return PTR_ERR(clk);
239
240 ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
241 if (ret) {
242 dev_err(dev, "failed to register OF clock provider\n");
243 return ret;
244 }
245
246 /* initialize buffer to zero */
247 regmap_write(stub_clk->dfs_map, ACPU_DFS_FLAG, 0x0);
248 regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, 0x0);
249 regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, 0x0);
250
251 dev_dbg(dev, "Registered clock '%s'\n", init.name);
252 return 0;
253 }
254
255 static const struct of_device_id hi6220_stub_clk_of_match[] = {
256 { .compatible = "hisilicon,hi6220-stub-clk", },
257 {}
258 };
259
260 static struct platform_driver hi6220_stub_clk_driver = {
261 .driver = {
262 .name = "hi6220-stub-clk",
263 .of_match_table = hi6220_stub_clk_of_match,
264 },
265 .probe = hi6220_stub_clk_probe,
266 };
267
hi6220_stub_clk_init(void)268 static int __init hi6220_stub_clk_init(void)
269 {
270 return platform_driver_register(&hi6220_stub_clk_driver);
271 }
272 subsys_initcall(hi6220_stub_clk_init);
273