1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Zynq UltraScale+ MPSoC Divider support
4 *
5 * Copyright (C) 2016-2019 Xilinx
6 *
7 * Adjustable divider clock implementation
8 */
9
10#include <linux/clk.h>
11#include <linux/clk-provider.h>
12#include <linux/slab.h>
13#include "clk-zynqmp.h"
14
15/*
16 * DOC: basic adjustable divider clock that cannot gate
17 *
18 * Traits of this clock:
19 * prepare - clk_prepare only ensures that parents are prepared
20 * enable - clk_enable only ensures that parents are enabled
21 * rate - rate is adjustable. clk->rate = ceiling(parent->rate / divisor)
22 * parent - fixed parent. No clk_set_parent support
23 */
24
25#define to_zynqmp_clk_divider(_hw) \
26 container_of(_hw, struct zynqmp_clk_divider, hw)
27
28#define CLK_FRAC BIT(13) /* has a fractional parent */
29#define CUSTOM_FLAG_CLK_FRAC BIT(0) /* has a fractional parent in custom type flag */
30
31/**
32 * struct zynqmp_clk_divider - adjustable divider clock
33 * @hw: handle between common and hardware-specific interfaces
34 * @flags: Hardware specific flags
35 * @is_frac: The divider is a fractional divider
36 * @clk_id: Id of clock
37 * @div_type: divisor type (TYPE_DIV1 or TYPE_DIV2)
38 * @max_div: maximum supported divisor (fetched from firmware)
39 */
40struct zynqmp_clk_divider {
41 struct clk_hw hw;
42 u8 flags;
43 bool is_frac;
44 u32 clk_id;
45 u32 div_type;
46 u16 max_div;
47};
48
49static inline int zynqmp_divider_get_val(unsigned long parent_rate,
50 unsigned long rate, u16 flags)
51{
52 int up, down;
53 unsigned long up_rate, down_rate;
54
55 if (flags & CLK_DIVIDER_POWER_OF_TWO) {
56 up = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
57 down = DIV_ROUND_DOWN_ULL((u64)parent_rate, rate);
58
59 up = __roundup_pow_of_two(n: up);
60 down = __rounddown_pow_of_two(n: down);
61
62 up_rate = DIV_ROUND_UP_ULL((u64)parent_rate, up);
63 down_rate = DIV_ROUND_UP_ULL((u64)parent_rate, down);
64
65 return (rate - up_rate) <= (down_rate - rate) ? up : down;
66
67 } else {
68 return DIV_ROUND_CLOSEST(parent_rate, rate);
69 }
70}
71
72/**
73 * zynqmp_clk_divider_recalc_rate() - Recalc rate of divider clock
74 * @hw: handle between common and hardware-specific interfaces
75 * @parent_rate: rate of parent clock
76 *
77 * Return: 0 on success else error+reason
78 */
79static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw,
80 unsigned long parent_rate)
81{
82 struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
83 const char *clk_name = clk_hw_get_name(hw);
84 u32 clk_id = divider->clk_id;
85 u32 div_type = divider->div_type;
86 u32 div, value;
87 int ret;
88
89 ret = zynqmp_pm_clock_getdivider(clock_id: clk_id, divider: &div);
90
91 if (ret)
92 pr_debug("%s() get divider failed for %s, ret = %d\n",
93 __func__, clk_name, ret);
94
95 if (div_type == TYPE_DIV1)
96 value = div & 0xFFFF;
97 else
98 value = div >> 16;
99
100 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
101 value = 1 << value;
102
103 if (!value) {
104 WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
105 "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
106 clk_name);
107 return parent_rate;
108 }
109
110 return DIV_ROUND_UP_ULL(parent_rate, value);
111}
112
113/**
114 * zynqmp_clk_divider_round_rate() - Round rate of divider clock
115 * @hw: handle between common and hardware-specific interfaces
116 * @rate: rate of clock to be set
117 * @prate: rate of parent clock
118 *
119 * Return: 0 on success else error+reason
120 */
121static long zynqmp_clk_divider_round_rate(struct clk_hw *hw,
122 unsigned long rate,
123 unsigned long *prate)
124{
125 struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
126 const char *clk_name = clk_hw_get_name(hw);
127 u32 clk_id = divider->clk_id;
128 u32 div_type = divider->div_type;
129 u32 bestdiv;
130 int ret;
131 u8 width;
132
133 /* if read only, just return current value */
134 if (divider->flags & CLK_DIVIDER_READ_ONLY) {
135 ret = zynqmp_pm_clock_getdivider(clock_id: clk_id, divider: &bestdiv);
136
137 if (ret)
138 pr_debug("%s() get divider failed for %s, ret = %d\n",
139 __func__, clk_name, ret);
140 if (div_type == TYPE_DIV1)
141 bestdiv = bestdiv & 0xFFFF;
142 else
143 bestdiv = bestdiv >> 16;
144
145 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
146 bestdiv = 1 << bestdiv;
147
148 return DIV_ROUND_UP_ULL((u64)*prate, bestdiv);
149 }
150
151 width = fls(x: divider->max_div);
152
153 rate = divider_round_rate(hw, rate, prate, NULL, width, flags: divider->flags);
154
155 if (divider->is_frac && (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && (rate % *prate))
156 *prate = rate;
157
158 return rate;
159}
160
161/**
162 * zynqmp_clk_divider_set_rate() - Set rate of divider clock
163 * @hw: handle between common and hardware-specific interfaces
164 * @rate: rate of clock to be set
165 * @parent_rate: rate of parent clock
166 *
167 * Return: 0 on success else error+reason
168 */
169static int zynqmp_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
170 unsigned long parent_rate)
171{
172 struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
173 const char *clk_name = clk_hw_get_name(hw);
174 u32 clk_id = divider->clk_id;
175 u32 div_type = divider->div_type;
176 u32 value, div;
177 int ret;
178
179 value = zynqmp_divider_get_val(parent_rate, rate, flags: divider->flags);
180 if (div_type == TYPE_DIV1) {
181 div = value & 0xFFFF;
182 div |= 0xffff << 16;
183 } else {
184 div = 0xffff;
185 div |= value << 16;
186 }
187
188 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
189 div = __ffs(div);
190
191 ret = zynqmp_pm_clock_setdivider(clock_id: clk_id, divider: div);
192
193 if (ret)
194 pr_debug("%s() set divider failed for %s, ret = %d\n",
195 __func__, clk_name, ret);
196
197 return ret;
198}
199
200static const struct clk_ops zynqmp_clk_divider_ops = {
201 .recalc_rate = zynqmp_clk_divider_recalc_rate,
202 .round_rate = zynqmp_clk_divider_round_rate,
203 .set_rate = zynqmp_clk_divider_set_rate,
204};
205
206static const struct clk_ops zynqmp_clk_divider_ro_ops = {
207 .recalc_rate = zynqmp_clk_divider_recalc_rate,
208 .round_rate = zynqmp_clk_divider_round_rate,
209};
210
211/**
212 * zynqmp_clk_get_max_divisor() - Get maximum supported divisor from firmware.
213 * @clk_id: Id of clock
214 * @type: Divider type
215 *
216 * Return: Maximum divisor of a clock if query data is successful
217 * U16_MAX in case of query data is not success
218 */
219static u32 zynqmp_clk_get_max_divisor(u32 clk_id, u32 type)
220{
221 struct zynqmp_pm_query_data qdata = {0};
222 u32 ret_payload[PAYLOAD_ARG_CNT];
223 int ret;
224
225 qdata.qid = PM_QID_CLOCK_GET_MAX_DIVISOR;
226 qdata.arg1 = clk_id;
227 qdata.arg2 = type;
228 ret = zynqmp_pm_query_data(qdata, out: ret_payload);
229 /*
230 * To maintain backward compatibility return maximum possible value
231 * (0xFFFF) if query for max divisor is not successful.
232 */
233 if (ret)
234 return U16_MAX;
235
236 return ret_payload[1];
237}
238
239static inline unsigned long zynqmp_clk_map_divider_ccf_flags(
240 const u32 zynqmp_type_flag)
241{
242 unsigned long ccf_flag = 0;
243
244 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ONE_BASED)
245 ccf_flag |= CLK_DIVIDER_ONE_BASED;
246 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_POWER_OF_TWO)
247 ccf_flag |= CLK_DIVIDER_POWER_OF_TWO;
248 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ALLOW_ZERO)
249 ccf_flag |= CLK_DIVIDER_ALLOW_ZERO;
250 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_POWER_OF_TWO)
251 ccf_flag |= CLK_DIVIDER_HIWORD_MASK;
252 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ROUND_CLOSEST)
253 ccf_flag |= CLK_DIVIDER_ROUND_CLOSEST;
254 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_READ_ONLY)
255 ccf_flag |= CLK_DIVIDER_READ_ONLY;
256 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_MAX_AT_ZERO)
257 ccf_flag |= CLK_DIVIDER_MAX_AT_ZERO;
258
259 return ccf_flag;
260}
261
262/**
263 * zynqmp_clk_register_divider() - Register a divider clock
264 * @name: Name of this clock
265 * @clk_id: Id of clock
266 * @parents: Name of this clock's parents
267 * @num_parents: Number of parents
268 * @nodes: Clock topology node
269 *
270 * Return: clock hardware to registered clock divider
271 */
272struct clk_hw *zynqmp_clk_register_divider(const char *name,
273 u32 clk_id,
274 const char * const *parents,
275 u8 num_parents,
276 const struct clock_topology *nodes)
277{
278 struct zynqmp_clk_divider *div;
279 struct clk_hw *hw;
280 struct clk_init_data init;
281 int ret;
282
283 /* allocate the divider */
284 div = kzalloc(size: sizeof(*div), GFP_KERNEL);
285 if (!div)
286 return ERR_PTR(error: -ENOMEM);
287
288 init.name = name;
289 if (nodes->type_flag & CLK_DIVIDER_READ_ONLY)
290 init.ops = &zynqmp_clk_divider_ro_ops;
291 else
292 init.ops = &zynqmp_clk_divider_ops;
293
294 init.flags = zynqmp_clk_map_common_ccf_flags(zynqmp_flag: nodes->flag);
295
296 init.parent_names = parents;
297 init.num_parents = 1;
298
299 /* struct clk_divider assignments */
300 div->is_frac = !!((nodes->flag & CLK_FRAC) |
301 (nodes->custom_type_flag & CUSTOM_FLAG_CLK_FRAC));
302 div->flags = zynqmp_clk_map_divider_ccf_flags(zynqmp_type_flag: nodes->type_flag);
303 div->hw.init = &init;
304 div->clk_id = clk_id;
305 div->div_type = nodes->type;
306
307 /*
308 * To achieve best possible rate, maximum limit of divider is required
309 * while computation.
310 */
311 div->max_div = zynqmp_clk_get_max_divisor(clk_id, type: nodes->type);
312
313 hw = &div->hw;
314 ret = clk_hw_register(NULL, hw);
315 if (ret) {
316 kfree(objp: div);
317 hw = ERR_PTR(error: ret);
318 }
319
320 return hw;
321}
322

source code of linux/drivers/clk/zynqmp/divider.c