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174 lines
4.4 KiB
C
174 lines
4.4 KiB
C
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/*
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* DPLL + CORE_CLK composite clock functions
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*
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* Copyright (C) 2005-2008 Texas Instruments, Inc.
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* Copyright (C) 2004-2010 Nokia Corporation
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*
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* Contacts:
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* Richard Woodruff <r-woodruff2@ti.com>
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* Paul Walmsley
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*
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* Based on earlier work by Tuukka Tikkanen, Tony Lindgren,
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* Gordon McNutt and RidgeRun, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* XXX The DPLL and CORE clocks should be split into two separate clock
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* types.
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*/
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#undef DEBUG
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <plat/clock.h>
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#include <plat/sram.h>
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#include <plat/sdrc.h>
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#include "clock.h"
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#include "clock2xxx.h"
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#include "opp2xxx.h"
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#include "cm.h"
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#include "cm-regbits-24xx.h"
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/* #define DOWN_VARIABLE_DPLL 1 */ /* Experimental */
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/**
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* omap2xxx_clk_get_core_rate - return the CORE_CLK rate
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* @clk: pointer to the combined dpll_ck + core_ck (currently "dpll_ck")
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*
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* Returns the CORE_CLK rate. CORE_CLK can have one of three rate
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* sources on OMAP2xxx: the DPLL CLKOUT rate, DPLL CLKOUTX2, or 32KHz
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* (the latter is unusual). This currently should be called with
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* struct clk *dpll_ck, which is a composite clock of dpll_ck and
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* core_ck.
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*/
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unsigned long omap2xxx_clk_get_core_rate(struct clk *clk)
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{
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long long core_clk;
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u32 v;
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core_clk = omap2_get_dpll_rate(clk);
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v = cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
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v &= OMAP24XX_CORE_CLK_SRC_MASK;
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if (v == CORE_CLK_SRC_32K)
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core_clk = 32768;
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else
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core_clk *= v;
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return core_clk;
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}
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/*
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* Uses the current prcm set to tell if a rate is valid.
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* You can go slower, but not faster within a given rate set.
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*/
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static long omap2_dpllcore_round_rate(unsigned long target_rate)
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{
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u32 high, low, core_clk_src;
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core_clk_src = cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
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core_clk_src &= OMAP24XX_CORE_CLK_SRC_MASK;
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if (core_clk_src == CORE_CLK_SRC_DPLL) { /* DPLL clockout */
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high = curr_prcm_set->dpll_speed * 2;
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low = curr_prcm_set->dpll_speed;
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} else { /* DPLL clockout x 2 */
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high = curr_prcm_set->dpll_speed;
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low = curr_prcm_set->dpll_speed / 2;
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}
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#ifdef DOWN_VARIABLE_DPLL
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if (target_rate > high)
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return high;
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else
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return target_rate;
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#else
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if (target_rate > low)
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return high;
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else
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return low;
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#endif
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}
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unsigned long omap2_dpllcore_recalc(struct clk *clk)
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{
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return omap2xxx_clk_get_core_rate(clk);
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}
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int omap2_reprogram_dpllcore(struct clk *clk, unsigned long rate)
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{
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u32 cur_rate, low, mult, div, valid_rate, done_rate;
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u32 bypass = 0;
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struct prcm_config tmpset;
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const struct dpll_data *dd;
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cur_rate = omap2xxx_clk_get_core_rate(dclk);
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mult = cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
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mult &= OMAP24XX_CORE_CLK_SRC_MASK;
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if ((rate == (cur_rate / 2)) && (mult == 2)) {
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omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL, 1);
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} else if ((rate == (cur_rate * 2)) && (mult == 1)) {
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omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
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} else if (rate != cur_rate) {
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valid_rate = omap2_dpllcore_round_rate(rate);
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if (valid_rate != rate)
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return -EINVAL;
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if (mult == 1)
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low = curr_prcm_set->dpll_speed;
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else
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low = curr_prcm_set->dpll_speed / 2;
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dd = clk->dpll_data;
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if (!dd)
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return -EINVAL;
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tmpset.cm_clksel1_pll = __raw_readl(dd->mult_div1_reg);
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tmpset.cm_clksel1_pll &= ~(dd->mult_mask |
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dd->div1_mask);
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div = ((curr_prcm_set->xtal_speed / 1000000) - 1);
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tmpset.cm_clksel2_pll = cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
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tmpset.cm_clksel2_pll &= ~OMAP24XX_CORE_CLK_SRC_MASK;
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if (rate > low) {
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tmpset.cm_clksel2_pll |= CORE_CLK_SRC_DPLL_X2;
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mult = ((rate / 2) / 1000000);
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done_rate = CORE_CLK_SRC_DPLL_X2;
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} else {
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tmpset.cm_clksel2_pll |= CORE_CLK_SRC_DPLL;
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mult = (rate / 1000000);
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done_rate = CORE_CLK_SRC_DPLL;
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}
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tmpset.cm_clksel1_pll |= (div << __ffs(dd->mult_mask));
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tmpset.cm_clksel1_pll |= (mult << __ffs(dd->div1_mask));
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/* Worst case */
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tmpset.base_sdrc_rfr = SDRC_RFR_CTRL_BYPASS;
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if (rate == curr_prcm_set->xtal_speed) /* If asking for 1-1 */
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bypass = 1;
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/* For omap2xxx_sdrc_init_params() */
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omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
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/* Force dll lock mode */
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omap2_set_prcm(tmpset.cm_clksel1_pll, tmpset.base_sdrc_rfr,
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bypass);
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/* Errata: ret dll entry state */
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omap2xxx_sdrc_init_params(omap2xxx_sdrc_dll_is_unlocked());
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omap2xxx_sdrc_reprogram(done_rate, 0);
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}
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return 0;
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}
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