arch/arm/mach-omap2/clkt2xxx_dpllcore.c

   1 /*
   2  * DPLL + CORE_CLK composite 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 The DPLL and CORE clocks should be split into two separate clock
  19  * types.
  20  */
  21 #undef DEBUG
  22
  23 #include <linux/kernel.h>
  24 #include <linux/errno.h>
  25 #include <linux/clk.h>
  26 #include <linux/io.h>
  27
  28 #include "clock.h"
  29 #include "clock2xxx.h"
  30 #include "opp2xxx.h"
  31 #include "cm2xxx.h"
  32 #include "cm-regbits-24xx.h"
  33 #include "sdrc.h"
  34 #include "sram.h"
  35
  36 /* #define DOWN_VARIABLE_DPLL 1 */              /* Experimental */
  37
  38 /*
  39  * dpll_core_ck: pointer to the combined dpll_ck + core_ck on OMAP2xxx
  40  * (currently defined as "dpll_ck" in the OMAP2xxx clock tree).  Set
  41  * during dpll_ck init and used later by omap2xxx_clk_get_core_rate().
  42  */
  43 static struct clk *dpll_core_ck;
  44
  45 /**
  46  * omap2xxx_clk_get_core_rate - return the CORE_CLK rate
  47  *
  48  * Returns the CORE_CLK rate.  CORE_CLK can have one of three rate
  49  * sources on OMAP2xxx: the DPLL CLKOUT rate, DPLL CLKOUTX2, or 32KHz
  50  * (the latter is unusual).  This currently should be called with
  51  * struct clk *dpll_ck, which is a composite clock of dpll_ck and
  52  * core_ck.
  53  */
  54 unsigned long omap2xxx_clk_get_core_rate(void)
  55 {
  56         long long core_clk;
  57         u32 v;
  58
  59         WARN_ON(!dpll_core_ck);
  60
  61         core_clk = omap2_get_dpll_rate(dpll_core_ck);
  62
  63         v = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
  64         v &= OMAP24XX_CORE_CLK_SRC_MASK;
  65
  66         if (v == CORE_CLK_SRC_32K)
  67                 core_clk = 32768;
  68         else
  69                 core_clk *= v;
  70
  71         return core_clk;
  72 }
  73
  74 /*
  75  * Uses the current prcm set to tell if a rate is valid.
  76  * You can go slower, but not faster within a given rate set.
  77  */
  78 static long omap2_dpllcore_round_rate(unsigned long target_rate)
  79 {
  80         u32 high, low, core_clk_src;
  81
  82         core_clk_src = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
  83         core_clk_src &= OMAP24XX_CORE_CLK_SRC_MASK;
  84
  85         if (core_clk_src == CORE_CLK_SRC_DPLL) {        /* DPLL clockout */
  86                 high = curr_prcm_set->dpll_speed * 2;
  87                 low = curr_prcm_set->dpll_speed;
  88         } else {                                /* DPLL clockout x 2 */
  89                 high = curr_prcm_set->dpll_speed;
  90                 low = curr_prcm_set->dpll_speed / 2;
  91         }
  92
  93 #ifdef DOWN_VARIABLE_DPLL
  94         if (target_rate > high)
  95                 return high;
  96         else
  97                 return target_rate;
  98 #else
  99         if (target_rate > low)
 100                 return high;
 101         else
 102                 return low;
 103 #endif
 104
 105 }
 106
 107 unsigned long omap2_dpllcore_recalc(struct clk *clk)
 108 {
 109         return omap2xxx_clk_get_core_rate();
 110 }
 111
 112 int omap2_reprogram_dpllcore(struct clk *clk, unsigned long rate)
 113 {
 114         u32 cur_rate, low, mult, div, valid_rate, done_rate;
 115         u32 bypass = 0;
 116         struct prcm_config tmpset;
 117         const struct dpll_data *dd;
 118
 119         cur_rate = omap2xxx_clk_get_core_rate();
 120         mult = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
 121         mult &= OMAP24XX_CORE_CLK_SRC_MASK;
 122
 123         if ((rate == (cur_rate / 2)) && (mult == 2)) {
 124                 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL, 1);
 125         } else if ((rate == (cur_rate * 2)) && (mult == 1)) {
 126                 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
 127         } else if (rate != cur_rate) {
 128                 valid_rate = omap2_dpllcore_round_rate(rate);
 129                 if (valid_rate != rate)
 130                         return -EINVAL;
 131
 132                 if (mult == 1)
 133                         low = curr_prcm_set->dpll_speed;
 134                 else
 135                         low = curr_prcm_set->dpll_speed / 2;
 136
 137                 dd = clk->dpll_data;
 138                 if (!dd)
 139                         return -EINVAL;
 140
 141                 tmpset.cm_clksel1_pll = __raw_readl(dd->mult_div1_reg);
 142                 tmpset.cm_clksel1_pll &= ~(dd->mult_mask |
 143                                            dd->div1_mask);
 144                 div = ((curr_prcm_set->xtal_speed / 1000000) - 1);
 145                 tmpset.cm_clksel2_pll = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
 146                 tmpset.cm_clksel2_pll &= ~OMAP24XX_CORE_CLK_SRC_MASK;
 147                 if (rate > low) {
 148                         tmpset.cm_clksel2_pll |= CORE_CLK_SRC_DPLL_X2;
 149                         mult = ((rate / 2) / 1000000);
 150                         done_rate = CORE_CLK_SRC_DPLL_X2;
 151                 } else {
 152                         tmpset.cm_clksel2_pll |= CORE_CLK_SRC_DPLL;
 153                         mult = (rate / 1000000);
 154                         done_rate = CORE_CLK_SRC_DPLL;
 155                 }
 156                 tmpset.cm_clksel1_pll |= (div << __ffs(dd->mult_mask));
 157                 tmpset.cm_clksel1_pll |= (mult << __ffs(dd->div1_mask));
 158
 159                 /* Worst case */
 160                 tmpset.base_sdrc_rfr = SDRC_RFR_CTRL_BYPASS;
 161
 162                 if (rate == curr_prcm_set->xtal_speed)  /* If asking for 1-1 */
 163                         bypass = 1;
 164
 165                 /* For omap2xxx_sdrc_init_params() */
 166                 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
 167
 168                 /* Force dll lock mode */
 169                 omap2_set_prcm(tmpset.cm_clksel1_pll, tmpset.base_sdrc_rfr,
 170                                bypass);
 171
 172                 /* Errata: ret dll entry state */
 173                 omap2xxx_sdrc_init_params(omap2xxx_sdrc_dll_is_unlocked());
 174                 omap2xxx_sdrc_reprogram(done_rate, 0);
 175         }
 176
 177         return 0;
 178 }
 179
 180 /**
 181  * omap2xxx_clkt_dpllcore_init - clk init function for dpll_ck
 182  * @clk: struct clk *dpll_ck
 183  *
 184  * Store a local copy of @clk in dpll_core_ck so other code can query
 185  * the core rate without having to clk_get(), which can sleep.  Must
 186  * only be called once.  No return value.  XXX If the clock
 187  * registration process is ever changed such that dpll_ck is no longer
 188  * statically defined, this code may need to change to increment some
 189  * kind of use count on dpll_ck.
 190  */
 191 void omap2xxx_clkt_dpllcore_init(struct clk *clk)
 192 {
 193         WARN(dpll_core_ck, "dpll_core_ck already set - should never happen");
 194         dpll_core_ck = clk;
 195 }