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