1 // SPDX-License-Identifier: GPL-2.0
3 * Zynq UltraScale+ MPSoC Divider support
5 * Copyright (C) 2016-2019 Xilinx
7 * Adjustable divider clock implementation
10 #include <linux/clk.h>
11 #include <linux/clk-provider.h>
12 #include <linux/slab.h>
13 #include "clk-zynqmp.h"
16 * DOC: basic adjustable divider clock that cannot gate
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
25 #define to_zynqmp_clk_divider(_hw) \
26 container_of(_hw, struct zynqmp_clk_divider, hw)
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 */
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)
40 struct zynqmp_clk_divider {
49 static inline int zynqmp_divider_get_val(unsigned long parent_rate,
50 unsigned long rate, u16 flags)
53 unsigned long up_rate, down_rate;
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);
59 up = __roundup_pow_of_two(up);
60 down = __rounddown_pow_of_two(down);
62 up_rate = DIV_ROUND_UP_ULL((u64)parent_rate, up);
63 down_rate = DIV_ROUND_UP_ULL((u64)parent_rate, down);
65 return (rate - up_rate) <= (down_rate - rate) ? up : down;
68 return DIV_ROUND_CLOSEST(parent_rate, rate);
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
77 * Return: 0 on success else error+reason
79 static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw,
80 unsigned long parent_rate)
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;
89 ret = zynqmp_pm_clock_getdivider(clk_id, &div);
92 pr_debug("%s() get divider failed for %s, ret = %d\n",
93 __func__, clk_name, ret);
95 if (div_type == TYPE_DIV1)
100 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
104 WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
105 "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
110 return DIV_ROUND_UP_ULL(parent_rate, value);
113 static void zynqmp_get_divider2_val(struct clk_hw *hw,
115 struct zynqmp_clk_divider *divider,
120 long error = LONG_MAX;
121 unsigned long div1_prate;
122 struct clk_hw *div1_parent_hw;
123 struct zynqmp_clk_divider *pdivider;
124 struct clk_hw *div2_parent_hw = clk_hw_get_parent(hw);
129 pdivider = to_zynqmp_clk_divider(div2_parent_hw);
133 div1_parent_hw = clk_hw_get_parent(div2_parent_hw);
137 div1_prate = clk_hw_get_rate(div1_parent_hw);
139 for (div1 = 1; div1 <= pdivider->max_div;) {
140 for (div2 = 1; div2 <= divider->max_div;) {
141 long new_error = ((div1_prate / div1) / div2) - rate;
143 if (abs(new_error) < abs(error)) {
147 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
152 if (pdivider->flags & CLK_DIVIDER_POWER_OF_TWO)
160 * zynqmp_clk_divider_round_rate() - Round rate of divider clock
161 * @hw: handle between common and hardware-specific interfaces
162 * @rate: rate of clock to be set
163 * @prate: rate of parent clock
165 * Return: 0 on success else error+reason
167 static long zynqmp_clk_divider_round_rate(struct clk_hw *hw,
169 unsigned long *prate)
171 struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
172 const char *clk_name = clk_hw_get_name(hw);
173 u32 clk_id = divider->clk_id;
174 u32 div_type = divider->div_type;
178 /* if read only, just return current value */
179 if (divider->flags & CLK_DIVIDER_READ_ONLY) {
180 ret = zynqmp_pm_clock_getdivider(clk_id, &bestdiv);
183 pr_debug("%s() get divider failed for %s, ret = %d\n",
184 __func__, clk_name, ret);
185 if (div_type == TYPE_DIV1)
186 bestdiv = bestdiv & 0xFFFF;
188 bestdiv = bestdiv >> 16;
190 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
191 bestdiv = 1 << bestdiv;
193 return DIV_ROUND_UP_ULL((u64)*prate, bestdiv);
196 bestdiv = zynqmp_divider_get_val(*prate, rate, divider->flags);
199 * In case of two divisors, compute best divider values and return
200 * divider2 value based on compute value. div1 will be automatically
201 * set to optimum based on required total divider value.
203 if (div_type == TYPE_DIV2 &&
204 (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
205 zynqmp_get_divider2_val(hw, rate, divider, &bestdiv);
208 if ((clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && divider->is_frac)
209 bestdiv = rate % *prate ? 1 : bestdiv;
211 bestdiv = min_t(u32, bestdiv, divider->max_div);
212 *prate = rate * bestdiv;
218 * zynqmp_clk_divider_set_rate() - Set rate of divider clock
219 * @hw: handle between common and hardware-specific interfaces
220 * @rate: rate of clock to be set
221 * @parent_rate: rate of parent clock
223 * Return: 0 on success else error+reason
225 static int zynqmp_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
226 unsigned long parent_rate)
228 struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
229 const char *clk_name = clk_hw_get_name(hw);
230 u32 clk_id = divider->clk_id;
231 u32 div_type = divider->div_type;
235 value = zynqmp_divider_get_val(parent_rate, rate, divider->flags);
236 if (div_type == TYPE_DIV1) {
237 div = value & 0xFFFF;
244 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
247 ret = zynqmp_pm_clock_setdivider(clk_id, div);
250 pr_debug("%s() set divider failed for %s, ret = %d\n",
251 __func__, clk_name, ret);
256 static const struct clk_ops zynqmp_clk_divider_ops = {
257 .recalc_rate = zynqmp_clk_divider_recalc_rate,
258 .round_rate = zynqmp_clk_divider_round_rate,
259 .set_rate = zynqmp_clk_divider_set_rate,
262 static const struct clk_ops zynqmp_clk_divider_ro_ops = {
263 .recalc_rate = zynqmp_clk_divider_recalc_rate,
264 .round_rate = zynqmp_clk_divider_round_rate,
268 * zynqmp_clk_get_max_divisor() - Get maximum supported divisor from firmware.
269 * @clk_id: Id of clock
270 * @type: Divider type
272 * Return: Maximum divisor of a clock if query data is successful
273 * U16_MAX in case of query data is not success
275 static u32 zynqmp_clk_get_max_divisor(u32 clk_id, u32 type)
277 struct zynqmp_pm_query_data qdata = {0};
278 u32 ret_payload[PAYLOAD_ARG_CNT];
281 qdata.qid = PM_QID_CLOCK_GET_MAX_DIVISOR;
284 ret = zynqmp_pm_query_data(qdata, ret_payload);
286 * To maintain backward compatibility return maximum possible value
287 * (0xFFFF) if query for max divisor is not successful.
292 return ret_payload[1];
295 static inline unsigned long zynqmp_clk_map_divider_ccf_flags(
296 const u32 zynqmp_type_flag)
298 unsigned long ccf_flag = 0;
300 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ONE_BASED)
301 ccf_flag |= CLK_DIVIDER_ONE_BASED;
302 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_POWER_OF_TWO)
303 ccf_flag |= CLK_DIVIDER_POWER_OF_TWO;
304 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ALLOW_ZERO)
305 ccf_flag |= CLK_DIVIDER_ALLOW_ZERO;
306 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_POWER_OF_TWO)
307 ccf_flag |= CLK_DIVIDER_HIWORD_MASK;
308 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ROUND_CLOSEST)
309 ccf_flag |= CLK_DIVIDER_ROUND_CLOSEST;
310 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_READ_ONLY)
311 ccf_flag |= CLK_DIVIDER_READ_ONLY;
312 if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_MAX_AT_ZERO)
313 ccf_flag |= CLK_DIVIDER_MAX_AT_ZERO;
319 * zynqmp_clk_register_divider() - Register a divider clock
320 * @name: Name of this clock
321 * @clk_id: Id of clock
322 * @parents: Name of this clock's parents
323 * @num_parents: Number of parents
324 * @nodes: Clock topology node
326 * Return: clock hardware to registered clock divider
328 struct clk_hw *zynqmp_clk_register_divider(const char *name,
330 const char * const *parents,
332 const struct clock_topology *nodes)
334 struct zynqmp_clk_divider *div;
336 struct clk_init_data init;
339 /* allocate the divider */
340 div = kzalloc(sizeof(*div), GFP_KERNEL);
342 return ERR_PTR(-ENOMEM);
345 if (nodes->type_flag & CLK_DIVIDER_READ_ONLY)
346 init.ops = &zynqmp_clk_divider_ro_ops;
348 init.ops = &zynqmp_clk_divider_ops;
350 init.flags = zynqmp_clk_map_common_ccf_flags(nodes->flag);
352 init.parent_names = parents;
353 init.num_parents = 1;
355 /* struct clk_divider assignments */
356 div->is_frac = !!((nodes->flag & CLK_FRAC) |
357 (nodes->custom_type_flag & CUSTOM_FLAG_CLK_FRAC));
358 div->flags = zynqmp_clk_map_divider_ccf_flags(nodes->type_flag);
359 div->hw.init = &init;
360 div->clk_id = clk_id;
361 div->div_type = nodes->type;
364 * To achieve best possible rate, maximum limit of divider is required
367 div->max_div = zynqmp_clk_get_max_divisor(clk_id, nodes->type);
370 ret = clk_hw_register(NULL, hw);