arch/arm/mach-omap2/clkt2xxx_virt_prcm_set.c

   1 /*
   2  * OMAP2xxx DVFS virtual clock functions
   3  *
   4  * Copyright (C) 2005-2008 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 <plat/cpu.h>
  37 #include <plat/clock.h>
  38 #include <plat/sram.h>
  39 #include <plat/sdrc.h>
  40
  41 #include "clock.h"
  42 #include "clock2xxx.h"
  43 #include "opp2xxx.h"
  44 #include "cm2xxx_3xxx.h"
  45 #include "cm-regbits-24xx.h"
  46
  47 const struct prcm_config *curr_prcm_set;
  48 const struct prcm_config *rate_table;
  49
  50 /**
  51  * omap2_table_mpu_recalc - just return the MPU speed
  52  * @clk: virt_prcm_set struct clk
  53  *
  54  * Set virt_prcm_set's rate to the mpu_speed field of the current PRCM set.
  55  */
  56 unsigned long omap2_table_mpu_recalc(struct clk *clk)
  57 {
  58         return curr_prcm_set->mpu_speed;
  59 }
  60
  61 /*
  62  * Look for a rate equal or less than the target rate given a configuration set.
  63  *
  64  * What's not entirely clear is "which" field represents the key field.
  65  * Some might argue L3-DDR, others ARM, others IVA. This code is simple and
  66  * just uses the ARM rates.
  67  */
  68 long omap2_round_to_table_rate(struct clk *clk, unsigned long rate)
  69 {
  70         const struct prcm_config *ptr;
  71         long highest_rate;
  72
  73         highest_rate = -EINVAL;
  74
  75         for (ptr = rate_table; ptr->mpu_speed; ptr++) {
  76                 if (!(ptr->flags & cpu_mask))
  77                         continue;
  78                 if (ptr->xtal_speed != sclk->rate)
  79                         continue;
  80
  81                 highest_rate = ptr->mpu_speed;
  82
  83                 /* Can check only after xtal frequency check */
  84                 if (ptr->mpu_speed <= rate)
  85                         break;
  86         }
  87         return highest_rate;
  88 }
  89
  90 /* Sets basic clocks based on the specified rate */
  91 int omap2_select_table_rate(struct clk *clk, unsigned long rate)
  92 {
  93         u32 cur_rate, done_rate, bypass = 0, tmp;
  94         const struct prcm_config *prcm;
  95         unsigned long found_speed = 0;
  96         unsigned long flags;
  97
  98         for (prcm = rate_table; prcm->mpu_speed; prcm++) {
  99                 if (!(prcm->flags & cpu_mask))
 100                         continue;
 101
 102                 if (prcm->xtal_speed != sclk->rate)
 103                         continue;
 104
 105                 if (prcm->mpu_speed <= rate) {
 106                         found_speed = prcm->mpu_speed;
 107                         break;
 108                 }
 109         }
 110
 111         if (!found_speed) {
 112                 printk(KERN_INFO "Could not set MPU rate to %luMHz\n",
 113                        rate / 1000000);
 114                 return -EINVAL;
 115         }
 116
 117         curr_prcm_set = prcm;
 118         cur_rate = omap2xxx_clk_get_core_rate(dclk);
 119
 120         if (prcm->dpll_speed == cur_rate / 2) {
 121                 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL, 1);
 122         } else if (prcm->dpll_speed == cur_rate * 2) {
 123                 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
 124         } else if (prcm->dpll_speed != cur_rate) {
 125                 local_irq_save(flags);
 126
 127                 if (prcm->dpll_speed == prcm->xtal_speed)
 128                         bypass = 1;
 129
 130                 if ((prcm->cm_clksel2_pll & OMAP24XX_CORE_CLK_SRC_MASK) ==
 131                     CORE_CLK_SRC_DPLL_X2)
 132                         done_rate = CORE_CLK_SRC_DPLL_X2;
 133                 else
 134                         done_rate = CORE_CLK_SRC_DPLL;
 135
 136                 /* MPU divider */
 137                 omap2_cm_write_mod_reg(prcm->cm_clksel_mpu, MPU_MOD, CM_CLKSEL);
 138
 139                 /* dsp + iva1 div(2420), iva2.1(2430) */
 140                 omap2_cm_write_mod_reg(prcm->cm_clksel_dsp,
 141                                  OMAP24XX_DSP_MOD, CM_CLKSEL);
 142
 143                 omap2_cm_write_mod_reg(prcm->cm_clksel_gfx, GFX_MOD, CM_CLKSEL);
 144
 145                 /* Major subsystem dividers */
 146                 tmp = omap2_cm_read_mod_reg(CORE_MOD, CM_CLKSEL1) & OMAP24XX_CLKSEL_DSS2_MASK;
 147                 omap2_cm_write_mod_reg(prcm->cm_clksel1_core | tmp, CORE_MOD,
 148                                  CM_CLKSEL1);
 149
 150                 if (cpu_is_omap2430())
 151                         omap2_cm_write_mod_reg(prcm->cm_clksel_mdm,
 152                                          OMAP2430_MDM_MOD, CM_CLKSEL);
 153
 154                 /* x2 to enter omap2xxx_sdrc_init_params() */
 155                 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
 156
 157                 omap2_set_prcm(prcm->cm_clksel1_pll, prcm->base_sdrc_rfr,
 158                                bypass);
 159
 160                 omap2xxx_sdrc_init_params(omap2xxx_sdrc_dll_is_unlocked());
 161                 omap2xxx_sdrc_reprogram(done_rate, 0);
 162
 163                 local_irq_restore(flags);
 164         }
 165
 166         return 0;
 167 }