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/*
* DPLL + CORE_CLK composite clock functions
*
* Copyright (C) 2005-2008 Texas Instruments, Inc.
* Copyright (C) 2004-2010 Nokia Corporation
*
* Contacts:
* Richard Woodruff <r-woodruff2@ti.com>
* Paul Walmsley
*
* Based on earlier work by Tuukka Tikkanen, Tony Lindgren,
* Gordon McNutt and RidgeRun, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* XXX The DPLL and CORE clocks should be split into two separate clock
* types.
*/
#undef DEBUG
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/clk.h>
#include <linux/io.h>
#include "clock.h"
#include "clock2xxx.h"
#include "opp2xxx.h"
#include "cm2xxx.h"
#include "cm-regbits-24xx.h"
#include "sdrc.h"
#include "sram.h"
/* #define DOWN_VARIABLE_DPLL 1 */ /* Experimental */
/*
* dpll_core_ck: pointer to the combined dpll_ck + core_ck on OMAP2xxx
* (currently defined as "dpll_ck" in the OMAP2xxx clock tree). Set
* during dpll_ck init and used later by omap2xxx_clk_get_core_rate().
*/
static struct clk *dpll_core_ck;
/**
* omap2xxx_clk_get_core_rate - return the CORE_CLK rate
*
* Returns the CORE_CLK rate. CORE_CLK can have one of three rate
* sources on OMAP2xxx: the DPLL CLKOUT rate, DPLL CLKOUTX2, or 32KHz
* (the latter is unusual). This currently should be called with
* struct clk *dpll_ck, which is a composite clock of dpll_ck and
* core_ck.
*/
unsigned long omap2xxx_clk_get_core_rate(void)
{
long long core_clk;
u32 v;
WARN_ON(!dpll_core_ck);
core_clk = omap2_get_dpll_rate(dpll_core_ck);
v = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
v &= OMAP24XX_CORE_CLK_SRC_MASK;
if (v == CORE_CLK_SRC_32K)
core_clk = 32768;
else
core_clk *= v;
return core_clk;
}
/*
* Uses the current prcm set to tell if a rate is valid.
* You can go slower, but not faster within a given rate set.
*/
static long omap2_dpllcore_round_rate(unsigned long target_rate)
{
u32 high, low, core_clk_src;
core_clk_src = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
core_clk_src &= OMAP24XX_CORE_CLK_SRC_MASK;
if (core_clk_src == CORE_CLK_SRC_DPLL) { /* DPLL clockout */
high = curr_prcm_set->dpll_speed * 2;
low = curr_prcm_set->dpll_speed;
} else { /* DPLL clockout x 2 */
high = curr_prcm_set->dpll_speed;
low = curr_prcm_set->dpll_speed / 2;
}
#ifdef DOWN_VARIABLE_DPLL
if (target_rate > high)
return high;
else
return target_rate;
#else
if (target_rate > low)
return high;
else
return low;
#endif
}
unsigned long omap2_dpllcore_recalc(struct clk *clk)
{
return omap2xxx_clk_get_core_rate();
}
int omap2_reprogram_dpllcore(struct clk *clk, unsigned long rate)
{
u32 cur_rate, low, mult, div, valid_rate, done_rate;
u32 bypass = 0;
struct prcm_config tmpset;
const struct dpll_data *dd;
cur_rate = omap2xxx_clk_get_core_rate();
mult = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
mult &= OMAP24XX_CORE_CLK_SRC_MASK;
if ((rate == (cur_rate / 2)) && (mult == 2)) {
omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL, 1);
} else if ((rate == (cur_rate * 2)) && (mult == 1)) {
omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
} else if (rate != cur_rate) {
valid_rate = omap2_dpllcore_round_rate(rate);
if (valid_rate != rate)
return -EINVAL;
if (mult == 1)
low = curr_prcm_set->dpll_speed;
else
low = curr_prcm_set->dpll_speed / 2;
dd = clk->dpll_data;
if (!dd)
return -EINVAL;
tmpset.cm_clksel1_pll = __raw_readl(dd->mult_div1_reg);
tmpset.cm_clksel1_pll &= ~(dd->mult_mask |
dd->div1_mask);
div = ((curr_prcm_set->xtal_speed / 1000000) - 1);
tmpset.cm_clksel2_pll = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKSEL2);
tmpset.cm_clksel2_pll &= ~OMAP24XX_CORE_CLK_SRC_MASK;
if (rate > low) {
tmpset.cm_clksel2_pll |= CORE_CLK_SRC_DPLL_X2;
mult = ((rate / 2) / 1000000);
done_rate = CORE_CLK_SRC_DPLL_X2;
} else {
tmpset.cm_clksel2_pll |= CORE_CLK_SRC_DPLL;
mult = (rate / 1000000);
done_rate = CORE_CLK_SRC_DPLL;
}
tmpset.cm_clksel1_pll |= (div << __ffs(dd->mult_mask));
tmpset.cm_clksel1_pll |= (mult << __ffs(dd->div1_mask));
/* Worst case */
tmpset.base_sdrc_rfr = SDRC_RFR_CTRL_BYPASS;
if (rate == curr_prcm_set->xtal_speed) /* If asking for 1-1 */
bypass = 1;
/* For omap2xxx_sdrc_init_params() */
omap2xxx_sdrc_reprogram(CORE_CLK_SRC_DPLL_X2, 1);
/* Force dll lock mode */
omap2_set_prcm(tmpset.cm_clksel1_pll, tmpset.base_sdrc_rfr,
bypass);
/* Errata: ret dll entry state */
omap2xxx_sdrc_init_params(omap2xxx_sdrc_dll_is_unlocked());
omap2xxx_sdrc_reprogram(done_rate, 0);
}
return 0;
}
/**
* omap2xxx_clkt_dpllcore_init - clk init function for dpll_ck
* @clk: struct clk *dpll_ck
*
* Store a local copy of @clk in dpll_core_ck so other code can query
* the core rate without having to clk_get(), which can sleep. Must
* only be called once. No return value. XXX If the clock
* registration process is ever changed such that dpll_ck is no longer
* statically defined, this code may need to change to increment some
* kind of use count on dpll_ck.
*/
void omap2xxx_clkt_dpllcore_init(struct clk *clk)
{
WARN(dpll_core_ck, "dpll_core_ck already set - should never happen");
dpll_core_ck = clk;
}
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