2 * OMAP2xxx DVFS virtual clock functions
4 * Copyright (C) 2005-2008, 2012 Texas Instruments, Inc.
5 * Copyright (C) 2004-2010 Nokia Corporation
8 * Richard Woodruff <r-woodruff2@ti.com>
11 * Based on earlier work by Tuukka Tikkanen, Tony Lindgren,
12 * Gordon McNutt and RidgeRun, Inc.
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.
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
29 #include <linux/kernel.h>
30 #include <linux/errno.h>
31 #include <linux/clk.h>
33 #include <linux/cpufreq.h>
34 #include <linux/slab.h>
38 #include "clock2xxx.h"
41 #include "cm-regbits-24xx.h"
45 const struct prcm_config *curr_prcm_set;
46 const struct prcm_config *rate_table;
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.
53 static unsigned long sys_ck_rate;
56 * omap2_table_mpu_recalc - just return the MPU speed
57 * @clk: virt_prcm_set struct clk
59 * Set virt_prcm_set's rate to the mpu_speed field of the current PRCM set.
61 unsigned long omap2_table_mpu_recalc(struct clk *clk)
63 return curr_prcm_set->mpu_speed;
67 * Look for a rate equal or less than the target rate given a configuration set.
69 * What's not entirely clear is "which" field represents the key field.
70 * Some might argue L3-DDR, others ARM, others IVA. This code is simple and
71 * just uses the ARM rates.
73 long omap2_round_to_table_rate(struct clk *clk, unsigned long rate)
75 const struct prcm_config *ptr;
78 highest_rate = -EINVAL;
80 for (ptr = rate_table; ptr->mpu_speed; ptr++) {
81 if (!(ptr->flags & cpu_mask))
83 if (ptr->xtal_speed != sys_ck_rate)
86 highest_rate = ptr->mpu_speed;
88 /* Can check only after xtal frequency check */
89 if (ptr->mpu_speed <= rate)
95 /* Sets basic clocks based on the specified rate */
96 int omap2_select_table_rate(struct clk *clk, unsigned long rate)
98 u32 cur_rate, done_rate, bypass = 0, tmp;
99 const struct prcm_config *prcm;
100 unsigned long found_speed = 0;
103 for (prcm = rate_table; prcm->mpu_speed; prcm++) {
104 if (!(prcm->flags & cpu_mask))
107 if (prcm->xtal_speed != sys_ck_rate)
110 if (prcm->mpu_speed <= rate) {
111 found_speed = prcm->mpu_speed;
117 printk(KERN_INFO "Could not set MPU rate to %luMHz\n",
122 curr_prcm_set = prcm;
123 cur_rate = omap2xxx_clk_get_core_rate();
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);
132 if (prcm->dpll_speed == prcm->xtal_speed)
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;
139 done_rate = CORE_CLK_SRC_DPLL;
142 omap2_cm_write_mod_reg(prcm->cm_clksel_mpu, MPU_MOD, CM_CLKSEL);
144 /* dsp + iva1 div(2420), iva2.1(2430) */
145 omap2_cm_write_mod_reg(prcm->cm_clksel_dsp,
146 OMAP24XX_DSP_MOD, CM_CLKSEL);
148 omap2_cm_write_mod_reg(prcm->cm_clksel_gfx, GFX_MOD, CM_CLKSEL);
150 /* Major subsystem dividers */
151 tmp = omap2_cm_read_mod_reg(CORE_MOD, CM_CLKSEL1) & OMAP24XX_CLKSEL_DSS2_MASK;
152 omap2_cm_write_mod_reg(prcm->cm_clksel1_core | tmp, CORE_MOD,
155 if (cpu_is_omap2430())
156 omap2_cm_write_mod_reg(prcm->cm_clksel_mdm,
157 OMAP2430_MDM_MOD, CM_CLKSEL);
159 /* x2 to enter omap2xxx_sdrc_init_params() */
160 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
162 omap2_set_prcm(prcm->cm_clksel1_pll, prcm->base_sdrc_rfr,
165 omap2xxx_sdrc_init_params(omap2xxx_sdrc_dll_is_unlocked());
166 omap2xxx_sdrc_reprogram(done_rate, 0);
168 local_irq_restore(flags);
175 * omap2xxx_clkt_vps_check_bootloader_rate - determine which of the rate
176 * table sets matches the current CORE DPLL hardware rate
178 * Check the MPU rate set by bootloader. Sets the 'curr_prcm_set'
179 * global to point to the active rate set when found; otherwise, sets
180 * it to NULL. No return value;
182 void omap2xxx_clkt_vps_check_bootloader_rates(void)
184 const struct prcm_config *prcm = NULL;
187 rate = omap2xxx_clk_get_core_rate();
188 for (prcm = rate_table; prcm->mpu_speed; prcm++) {
189 if (!(prcm->flags & cpu_mask))
191 if (prcm->xtal_speed != sys_ck_rate)
193 if (prcm->dpll_speed <= rate)
196 curr_prcm_set = prcm;
200 * omap2xxx_clkt_vps_late_init - store a copy of the sys_ck rate
202 * Store a copy of the sys_ck rate for later use by the OMAP2xxx DVFS
203 * code. (The sys_ck rate does not -- or rather, must not -- change
204 * during kernel runtime.) Must be called after we have a valid
205 * sys_ck rate, but before the virt_prcm_set clock rate is
206 * recalculated. No return value.
208 void omap2xxx_clkt_vps_late_init(void)
212 c = clk_get(NULL, "sys_ck");
214 WARN(1, "could not locate sys_ck\n");
216 sys_ck_rate = clk_get_rate(c);