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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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