arch/arm/mach-omap2/clkt2xxx_virt_prcm_set.c

   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