1 /*
2 * Marvell EBU SoC common clock handling
3 *
4 * Copyright (C) 2012 Marvell
5 *
6 * Gregory CLEMENT <gregory.clement@free-electrons.com>
7 * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
8 * Andrew Lunn <andrew@lunn.ch>
9 *
10 * This file is licensed under the terms of the GNU General Public
11 * License version 2. This program is licensed "as is" without any
12 * warranty of any kind, whether express or implied.
13 */
14
15 #include <linux/kernel.h>
16 #include <linux/slab.h>
17 #include <linux/clk.h>
18 #include <linux/clk-provider.h>
19 #include <linux/io.h>
20 #include <linux/of.h>
21 #include <linux/of_address.h>
22 #include <linux/syscore_ops.h>
23
24 #include "common.h"
25
26 /*
27 * Core Clocks
28 */
29
30 #define SSCG_CONF_MODE(reg) (((reg) >> 16) & 0x3)
31 #define SSCG_SPREAD_DOWN 0x0
32 #define SSCG_SPREAD_UP 0x1
33 #define SSCG_SPREAD_CENTRAL 0x2
34 #define SSCG_CONF_LOW(reg) (((reg) >> 8) & 0xFF)
35 #define SSCG_CONF_HIGH(reg) ((reg) & 0xFF)
36
37 static struct clk_onecell_data clk_data;
38
39 /*
40 * This function can be used by the Kirkwood, the Armada 370, the
41 * Armada XP and the Armada 375 SoC. The name of the function was
42 * chosen following the dt convention: using the first known SoC
43 * compatible with it.
44 */
kirkwood_fix_sscg_deviation(u32 system_clk)45 u32 kirkwood_fix_sscg_deviation(u32 system_clk)
46 {
47 struct device_node *sscg_np = NULL;
48 void __iomem *sscg_map;
49 u32 sscg_reg;
50 s32 low_bound, high_bound;
51 u64 freq_swing_half;
52
53 sscg_np = of_find_node_by_name(NULL, "sscg");
54 if (sscg_np == NULL) {
55 pr_err("cannot get SSCG register node\n");
56 return system_clk;
57 }
58
59 sscg_map = of_iomap(sscg_np, 0);
60 if (sscg_map == NULL) {
61 pr_err("cannot map SSCG register\n");
62 goto out;
63 }
64
65 sscg_reg = readl(sscg_map);
66 high_bound = SSCG_CONF_HIGH(sscg_reg);
67 low_bound = SSCG_CONF_LOW(sscg_reg);
68
69 if ((high_bound - low_bound) <= 0)
70 goto out;
71 /*
72 * From Marvell engineer we got the following formula (when
73 * this code was written, the datasheet was erroneous)
74 * Spread percentage = 1/96 * (H - L) / H
75 * H = SSCG_High_Boundary
76 * L = SSCG_Low_Boundary
77 *
78 * As the deviation is half of spread then it lead to the
79 * following formula in the code.
80 *
81 * To avoid an overflow and not lose any significant digit in
82 * the same time we have to use a 64 bit integer.
83 */
84
85 freq_swing_half = (((u64)high_bound - (u64)low_bound)
86 * (u64)system_clk);
87 do_div(freq_swing_half, (2 * 96 * high_bound));
88
89 switch (SSCG_CONF_MODE(sscg_reg)) {
90 case SSCG_SPREAD_DOWN:
91 system_clk -= freq_swing_half;
92 break;
93 case SSCG_SPREAD_UP:
94 system_clk += freq_swing_half;
95 break;
96 case SSCG_SPREAD_CENTRAL:
97 default:
98 break;
99 }
100
101 iounmap(sscg_map);
102
103 out:
104 of_node_put(sscg_np);
105
106 return system_clk;
107 }
108
mvebu_coreclk_setup(struct device_node * np,const struct coreclk_soc_desc * desc)109 void __init mvebu_coreclk_setup(struct device_node *np,
110 const struct coreclk_soc_desc *desc)
111 {
112 const char *tclk_name = "tclk";
113 const char *cpuclk_name = "cpuclk";
114 void __iomem *base;
115 unsigned long rate;
116 int n;
117
118 base = of_iomap(np, 0);
119 if (WARN_ON(!base))
120 return;
121
122 /* Allocate struct for TCLK, cpu clk, and core ratio clocks */
123 clk_data.clk_num = 2 + desc->num_ratios;
124
125 /* One more clock for the optional refclk */
126 if (desc->get_refclk_freq)
127 clk_data.clk_num += 1;
128
129 clk_data.clks = kcalloc(clk_data.clk_num, sizeof(*clk_data.clks),
130 GFP_KERNEL);
131 if (WARN_ON(!clk_data.clks)) {
132 iounmap(base);
133 return;
134 }
135
136 /* Register TCLK */
137 of_property_read_string_index(np, "clock-output-names", 0,
138 &tclk_name);
139 rate = desc->get_tclk_freq(base);
140 clk_data.clks[0] = clk_register_fixed_rate(NULL, tclk_name, NULL, 0,
141 rate);
142 WARN_ON(IS_ERR(clk_data.clks[0]));
143
144 /* Register CPU clock */
145 of_property_read_string_index(np, "clock-output-names", 1,
146 &cpuclk_name);
147 rate = desc->get_cpu_freq(base);
148
149 if (desc->is_sscg_enabled && desc->fix_sscg_deviation
150 && desc->is_sscg_enabled(base))
151 rate = desc->fix_sscg_deviation(rate);
152
153 clk_data.clks[1] = clk_register_fixed_rate(NULL, cpuclk_name, NULL, 0,
154 rate);
155 WARN_ON(IS_ERR(clk_data.clks[1]));
156
157 /* Register fixed-factor clocks derived from CPU clock */
158 for (n = 0; n < desc->num_ratios; n++) {
159 const char *rclk_name = desc->ratios[n].name;
160 int mult, div;
161
162 of_property_read_string_index(np, "clock-output-names",
163 2+n, &rclk_name);
164 desc->get_clk_ratio(base, desc->ratios[n].id, &mult, &div);
165 clk_data.clks[2+n] = clk_register_fixed_factor(NULL, rclk_name,
166 cpuclk_name, 0, mult, div);
167 WARN_ON(IS_ERR(clk_data.clks[2+n]));
168 }
169
170 /* Register optional refclk */
171 if (desc->get_refclk_freq) {
172 const char *name = "refclk";
173 of_property_read_string_index(np, "clock-output-names",
174 2 + desc->num_ratios, &name);
175 rate = desc->get_refclk_freq(base);
176 clk_data.clks[2 + desc->num_ratios] =
177 clk_register_fixed_rate(NULL, name, NULL, 0, rate);
178 WARN_ON(IS_ERR(clk_data.clks[2 + desc->num_ratios]));
179 }
180
181 /* SAR register isn't needed anymore */
182 iounmap(base);
183
184 of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
185 }
186
187 /*
188 * Clock Gating Control
189 */
190
191 DEFINE_SPINLOCK(ctrl_gating_lock);
192
193 struct clk_gating_ctrl {
194 spinlock_t *lock;
195 struct clk **gates;
196 int num_gates;
197 void __iomem *base;
198 u32 saved_reg;
199 };
200
201 static struct clk_gating_ctrl *ctrl;
202
clk_gating_get_src(struct of_phandle_args * clkspec,void * data)203 static struct clk *clk_gating_get_src(
204 struct of_phandle_args *clkspec, void *data)
205 {
206 int n;
207
208 if (clkspec->args_count < 1)
209 return ERR_PTR(-EINVAL);
210
211 for (n = 0; n < ctrl->num_gates; n++) {
212 struct clk_gate *gate =
213 to_clk_gate(__clk_get_hw(ctrl->gates[n]));
214 if (clkspec->args[0] == gate->bit_idx)
215 return ctrl->gates[n];
216 }
217 return ERR_PTR(-ENODEV);
218 }
219
mvebu_clk_gating_suspend(void)220 static int mvebu_clk_gating_suspend(void)
221 {
222 ctrl->saved_reg = readl(ctrl->base);
223 return 0;
224 }
225
mvebu_clk_gating_resume(void)226 static void mvebu_clk_gating_resume(void)
227 {
228 writel(ctrl->saved_reg, ctrl->base);
229 }
230
231 static struct syscore_ops clk_gate_syscore_ops = {
232 .suspend = mvebu_clk_gating_suspend,
233 .resume = mvebu_clk_gating_resume,
234 };
235
mvebu_clk_gating_setup(struct device_node * np,const struct clk_gating_soc_desc * desc)236 void __init mvebu_clk_gating_setup(struct device_node *np,
237 const struct clk_gating_soc_desc *desc)
238 {
239 struct clk *clk;
240 void __iomem *base;
241 const char *default_parent = NULL;
242 int n;
243
244 if (ctrl) {
245 pr_err("mvebu-clk-gating: cannot instantiate more than one gatable clock device\n");
246 return;
247 }
248
249 base = of_iomap(np, 0);
250 if (WARN_ON(!base))
251 return;
252
253 clk = of_clk_get(np, 0);
254 if (!IS_ERR(clk)) {
255 default_parent = __clk_get_name(clk);
256 clk_put(clk);
257 }
258
259 ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
260 if (WARN_ON(!ctrl))
261 goto ctrl_out;
262
263 /* lock must already be initialized */
264 ctrl->lock = &ctrl_gating_lock;
265
266 ctrl->base = base;
267
268 /* Count, allocate, and register clock gates */
269 for (n = 0; desc[n].name;)
270 n++;
271
272 ctrl->num_gates = n;
273 ctrl->gates = kcalloc(ctrl->num_gates, sizeof(*ctrl->gates),
274 GFP_KERNEL);
275 if (WARN_ON(!ctrl->gates))
276 goto gates_out;
277
278 for (n = 0; n < ctrl->num_gates; n++) {
279 const char *parent =
280 (desc[n].parent) ? desc[n].parent : default_parent;
281 ctrl->gates[n] = clk_register_gate(NULL, desc[n].name, parent,
282 desc[n].flags, base, desc[n].bit_idx,
283 0, ctrl->lock);
284 WARN_ON(IS_ERR(ctrl->gates[n]));
285 }
286
287 of_clk_add_provider(np, clk_gating_get_src, ctrl);
288
289 register_syscore_ops(&clk_gate_syscore_ops);
290
291 return;
292 gates_out:
293 kfree(ctrl);
294 ctrl_out:
295 iounmap(base);
296 }
297