1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * OMAP2xxx DVFS virtual clock functions
4 *
5 * Copyright (C) 2005-2008, 2012 Texas Instruments, Inc.
6 * Copyright (C) 2004-2010 Nokia Corporation
7 *
8 * Contacts:
9 * Richard Woodruff <r-woodruff2@ti.com>
10 * Paul Walmsley
11 *
12 * Based on earlier work by Tuukka Tikkanen, Tony Lindgren,
13 * Gordon McNutt and RidgeRun, Inc.
14 *
15 * XXX Some of this code should be replaceable by the upcoming OPP layer
16 * code. However, some notion of "rate set" is probably still necessary
17 * for OMAP2xxx at least. Rate sets should be generalized so they can be
18 * used for any OMAP chip, not just OMAP2xxx. In particular, Richard Woodruff
19 * has in the past expressed a preference to use rate sets for OPP changes,
20 * rather than dynamically recalculating the clock tree, so if someone wants
21 * this badly enough to write the code to handle it, we should support it
22 * as an option.
23 */
24 #undef DEBUG
25
26 #include <linux/kernel.h>
27 #include <linux/errno.h>
28 #include <linux/clk.h>
29 #include <linux/io.h>
30 #include <linux/cpufreq.h>
31 #include <linux/slab.h>
32
33 #include "soc.h"
34 #include "clock.h"
35 #include "clock2xxx.h"
36 #include "opp2xxx.h"
37 #include "cm2xxx.h"
38 #include "cm-regbits-24xx.h"
39 #include "sdrc.h"
40 #include "sram.h"
41
42 const struct prcm_config *curr_prcm_set;
43 const struct prcm_config *rate_table;
44
45 /*
46 * sys_ck_rate: the rate of the external high-frequency clock
47 * oscillator on the board. Set by the SoC-specific clock init code.
48 * Once set during a boot, will not change.
49 */
50 static unsigned long sys_ck_rate;
51
52 /**
53 * omap2_table_mpu_recalc - just return the MPU speed
54 * @clk: virt_prcm_set struct clk
55 *
56 * Set virt_prcm_set's rate to the mpu_speed field of the current PRCM set.
57 */
omap2_table_mpu_recalc(struct clk_hw * clk,unsigned long parent_rate)58 unsigned long omap2_table_mpu_recalc(struct clk_hw *clk,
59 unsigned long parent_rate)
60 {
61 return curr_prcm_set->mpu_speed;
62 }
63
64 /*
65 * Look for a rate equal or less than the target rate given a configuration set.
66 *
67 * What's not entirely clear is "which" field represents the key field.
68 * Some might argue L3-DDR, others ARM, others IVA. This code is simple and
69 * just uses the ARM rates.
70 */
omap2_round_to_table_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent_rate)71 long omap2_round_to_table_rate(struct clk_hw *hw, unsigned long rate,
72 unsigned long *parent_rate)
73 {
74 const struct prcm_config *ptr;
75 long highest_rate;
76
77 highest_rate = -EINVAL;
78
79 for (ptr = rate_table; ptr->mpu_speed; ptr++) {
80 if (!(ptr->flags & cpu_mask))
81 continue;
82 if (ptr->xtal_speed != sys_ck_rate)
83 continue;
84
85 highest_rate = ptr->mpu_speed;
86
87 /* Can check only after xtal frequency check */
88 if (ptr->mpu_speed <= rate)
89 break;
90 }
91 return highest_rate;
92 }
93
94 /* Sets basic clocks based on the specified rate */
omap2_select_table_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)95 int omap2_select_table_rate(struct clk_hw *hw, unsigned long rate,
96 unsigned long parent_rate)
97 {
98 u32 cur_rate, done_rate, bypass = 0;
99 const struct prcm_config *prcm;
100 unsigned long found_speed = 0;
101 unsigned long flags;
102
103 for (prcm = rate_table; prcm->mpu_speed; prcm++) {
104 if (!(prcm->flags & cpu_mask))
105 continue;
106
107 if (prcm->xtal_speed != sys_ck_rate)
108 continue;
109
110 if (prcm->mpu_speed <= rate) {
111 found_speed = prcm->mpu_speed;
112 break;
113 }
114 }
115
116 if (!found_speed) {
117 printk(KERN_INFO "Could not set MPU rate to %luMHz\n",
118 rate / 1000000);
119 return -EINVAL;
120 }
121
122 curr_prcm_set = prcm;
123 cur_rate = omap2xxx_clk_get_core_rate();
124
125 if (prcm->dpll_speed == cur_rate / 2) {
126 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL, 1);
127 } else if (prcm->dpll_speed == cur_rate * 2) {
128 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
129 } else if (prcm->dpll_speed != cur_rate) {
130 local_irq_save(flags);
131
132 if (prcm->dpll_speed == prcm->xtal_speed)
133 bypass = 1;
134
135 if ((prcm->cm_clksel2_pll & OMAP24XX_CORE_CLK_SRC_MASK) ==
136 CORE_CLK_SRC_DPLL_X2)
137 done_rate = CORE_CLK_SRC_DPLL_X2;
138 else
139 done_rate = CORE_CLK_SRC_DPLL;
140
141 omap2xxx_cm_set_mod_dividers(prcm->cm_clksel_mpu,
142 prcm->cm_clksel_dsp,
143 prcm->cm_clksel_gfx,
144 prcm->cm_clksel1_core,
145 prcm->cm_clksel_mdm);
146
147 /* x2 to enter omap2xxx_sdrc_init_params() */
148 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
149
150 omap2_set_prcm(prcm->cm_clksel1_pll, prcm->base_sdrc_rfr,
151 bypass);
152
153 omap2xxx_sdrc_init_params(omap2xxx_sdrc_dll_is_unlocked());
154 omap2xxx_sdrc_reprogram(done_rate, 0);
155
156 local_irq_restore(flags);
157 }
158
159 return 0;
160 }
161
162 /**
163 * omap2xxx_clkt_vps_check_bootloader_rate - determine which of the rate
164 * table sets matches the current CORE DPLL hardware rate
165 *
166 * Check the MPU rate set by bootloader. Sets the 'curr_prcm_set'
167 * global to point to the active rate set when found; otherwise, sets
168 * it to NULL. No return value;
169 */
omap2xxx_clkt_vps_check_bootloader_rates(void)170 void omap2xxx_clkt_vps_check_bootloader_rates(void)
171 {
172 const struct prcm_config *prcm = NULL;
173 unsigned long rate;
174
175 rate = omap2xxx_clk_get_core_rate();
176 for (prcm = rate_table; prcm->mpu_speed; prcm++) {
177 if (!(prcm->flags & cpu_mask))
178 continue;
179 if (prcm->xtal_speed != sys_ck_rate)
180 continue;
181 if (prcm->dpll_speed <= rate)
182 break;
183 }
184 curr_prcm_set = prcm;
185 }
186
187 /**
188 * omap2xxx_clkt_vps_late_init - store a copy of the sys_ck rate
189 *
190 * Store a copy of the sys_ck rate for later use by the OMAP2xxx DVFS
191 * code. (The sys_ck rate does not -- or rather, must not -- change
192 * during kernel runtime.) Must be called after we have a valid
193 * sys_ck rate, but before the virt_prcm_set clock rate is
194 * recalculated. No return value.
195 */
omap2xxx_clkt_vps_late_init(void)196 void omap2xxx_clkt_vps_late_init(void)
197 {
198 struct clk *c;
199
200 c = clk_get(NULL, "sys_ck");
201 if (IS_ERR(c)) {
202 WARN(1, "could not locate sys_ck\n");
203 } else {
204 sys_ck_rate = clk_get_rate(c);
205 clk_put(c);
206 }
207 }
208
209 #ifdef CONFIG_OF
210 #include <linux/clk-provider.h>
211 #include <linux/clkdev.h>
212
213 static const struct clk_ops virt_prcm_set_ops = {
214 .recalc_rate = &omap2_table_mpu_recalc,
215 .set_rate = &omap2_select_table_rate,
216 .round_rate = &omap2_round_to_table_rate,
217 };
218
219 /**
220 * omap2xxx_clkt_vps_init - initialize virt_prcm_set clock
221 *
222 * Does a manual init for the virtual prcm DVFS clock for OMAP2. This
223 * function is called only from omap2 DT clock init, as the virtual
224 * node is not modelled in the DT clock data.
225 */
omap2xxx_clkt_vps_init(void)226 void omap2xxx_clkt_vps_init(void)
227 {
228 struct clk_init_data init = { NULL };
229 struct clk_hw_omap *hw = NULL;
230 struct clk *clk;
231 const char *parent_name = "mpu_ck";
232
233 omap2xxx_clkt_vps_late_init();
234 omap2xxx_clkt_vps_check_bootloader_rates();
235
236 hw = kzalloc(sizeof(*hw), GFP_KERNEL);
237 if (!hw)
238 return;
239 init.name = "virt_prcm_set";
240 init.ops = &virt_prcm_set_ops;
241 init.parent_names = &parent_name;
242 init.num_parents = 1;
243
244 hw->hw.init = &init;
245
246 clk = clk_register(NULL, &hw->hw);
247 if (IS_ERR(clk)) {
248 printk(KERN_ERR "Failed to register clock\n");
249 kfree(hw);
250 return;
251 }
252
253 clkdev_create(clk, "cpufreq_ck", NULL);
254 }
255 #endif
256