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_3xxx.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  * omap2xxx_clk_get_core_rate - return the CORE_CLK rate
  40  * @clk: pointer to the combined dpll_ck + core_ck (currently "dpll_ck")
  41  *
  42  * Returns the CORE_CLK rate.  CORE_CLK can have one of three rate
  43  * sources on OMAP2xxx: the DPLL CLKOUT rate, DPLL CLKOUTX2, or 32KHz
  44  * (the latter is unusual).  This currently should be called with
  45  * struct clk *dpll_ck, which is a composite clock of dpll_ck and
  46  * core_ck.
  47  */
  48 unsigned long omap2xxx_clk_get_core_rate(struct clk *clk)
  49 {
  50         long long core_clk;
  51         u32 v;
  52
  53         core_clk = omap2_get_dpll_rate(clk);
  54
  55         v = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
  56         v &= OMAP24XX_CORE_CLK_SRC_MASK;
  57
  58         if (v == CORE_CLK_SRC_32K)
  59                 core_clk = 32768;
  60         else
  61                 core_clk *= v;
  62
  63         return core_clk;
  64 }
  65
  66 /*
  67  * Uses the current prcm set to tell if a rate is valid.
  68  * You can go slower, but not faster within a given rate set.
  69  */
  70 static long omap2_dpllcore_round_rate(unsigned long target_rate)
  71 {
  72         u32 high, low, core_clk_src;
  73
  74         core_clk_src = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
  75         core_clk_src &= OMAP24XX_CORE_CLK_SRC_MASK;
  76
  77         if (core_clk_src == CORE_CLK_SRC_DPLL) {        /* DPLL clockout */
  78                 high = curr_prcm_set->dpll_speed * 2;
  79                 low = curr_prcm_set->dpll_speed;
  80         } else {                                /* DPLL clockout x 2 */
  81                 high = curr_prcm_set->dpll_speed;
  82                 low = curr_prcm_set->dpll_speed / 2;
  83         }
  84
  85 #ifdef DOWN_VARIABLE_DPLL
  86         if (target_rate > high)
  87                 return high;
  88         else
  89                 return target_rate;
  90 #else
  91         if (target_rate > low)
  92                 return high;
  93         else
  94                 return low;
  95 #endif
  96
  97 }
  98
  99 unsigned long omap2_dpllcore_recalc(struct clk *clk)
 100 {
 101         return omap2xxx_clk_get_core_rate(clk);
 102 }
 103
 104 int omap2_reprogram_dpllcore(struct clk *clk, unsigned long rate)
 105 {
 106         u32 cur_rate, low, mult, div, valid_rate, done_rate;
 107         u32 bypass = 0;
 108         struct prcm_config tmpset;
 109         const struct dpll_data *dd;
 110
 111         cur_rate = omap2xxx_clk_get_core_rate(dclk);
 112         mult = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
 113         mult &= OMAP24XX_CORE_CLK_SRC_MASK;
 114
 115         if ((rate == (cur_rate / 2)) && (mult == 2)) {
 116                 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL, 1);
 117         } else if ((rate == (cur_rate * 2)) && (mult == 1)) {
 118                 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
 119         } else if (rate != cur_rate) {
 120                 valid_rate = omap2_dpllcore_round_rate(rate);
 121                 if (valid_rate != rate)
 122                         return -EINVAL;
 123
 124                 if (mult == 1)
 125                         low = curr_prcm_set->dpll_speed;
 126                 else
 127                         low = curr_prcm_set->dpll_speed / 2;
 128
 129                 dd = clk->dpll_data;
 130                 if (!dd)
 131                         return -EINVAL;
 132
 133                 tmpset.cm_clksel1_pll = __raw_readl(dd->mult_div1_reg);
 134                 tmpset.cm_clksel1_pll &= ~(dd->mult_mask |
 135                                            dd->div1_mask);
 136                 div = ((curr_prcm_set->xtal_speed / 1000000) - 1);
 137                 tmpset.cm_clksel2_pll = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
 138                 tmpset.cm_clksel2_pll &= ~OMAP24XX_CORE_CLK_SRC_MASK;
 139                 if (rate > low) {
 140                         tmpset.cm_clksel2_pll |= CORE_CLK_SRC_DPLL_X2;
 141                         mult = ((rate / 2) / 1000000);
 142                         done_rate = CORE_CLK_SRC_DPLL_X2;
 143                 } else {
 144                         tmpset.cm_clksel2_pll |= CORE_CLK_SRC_DPLL;
 145                         mult = (rate / 1000000);
 146                         done_rate = CORE_CLK_SRC_DPLL;
 147                 }
 148                 tmpset.cm_clksel1_pll |= (div << __ffs(dd->mult_mask));
 149                 tmpset.cm_clksel1_pll |= (mult << __ffs(dd->div1_mask));
 150
 151                 /* Worst case */
 152                 tmpset.base_sdrc_rfr = SDRC_RFR_CTRL_BYPASS;
 153
 154                 if (rate == curr_prcm_set->xtal_speed)  /* If asking for 1-1 */
 155                         bypass = 1;
 156
 157                 /* For omap2xxx_sdrc_init_params() */
 158                 omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
 159
 160                 /* Force dll lock mode */
 161                 omap2_set_prcm(tmpset.cm_clksel1_pll, tmpset.base_sdrc_rfr,
 162                                bypass);
 163
 164                 /* Errata: ret dll entry state */
 165                 omap2xxx_sdrc_init_params(omap2xxx_sdrc_dll_is_unlocked());
 166                 omap2xxx_sdrc_reprogram(done_rate, 0);
 167         }
 168
 169         return 0;
 170 }
 171