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clock.c

/* linux/arch/arm/mach-s3c2443/clock.c
 *
 * Copyright (c) 2007, 2010 Simtec Electronics
 *    Ben Dooks <ben@simtec.co.uk>
 *
 * S3C2443 Clock control support
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <linux/init.h>

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/sysdev.h>
#include <linux/clk.h>
#include <linux/mutex.h>
#include <linux/serial_core.h>
#include <linux/io.h>

#include <asm/mach/map.h>

#include <mach/hardware.h>

#include <mach/regs-s3c2443-clock.h>

#include <plat/cpu-freq.h>

#include <plat/s3c2443.h>
#include <plat/clock.h>
#include <plat/clock-clksrc.h>
#include <plat/cpu.h>

/* We currently have to assume that the system is running
 * from the XTPll input, and that all ***REFCLKs are being
 * fed from it, as we cannot read the state of OM[4] from
 * software.
 *
 * It would be possible for each board initialisation to
 * set the correct muxing at initialisation
*/

/* clock selections */

static struct clk clk_i2s_ext = {
      .name       = "i2s-ext",
      .id         = -1,
};

/* armdiv
 *
 * this clock is sourced from msysclk and can have a number of
 * divider values applied to it to then be fed into armclk.
*/

/* armdiv divisor table */

static unsigned int armdiv[16] = {
      [S3C2443_CLKDIV0_ARMDIV_1 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]  = 1,
      [S3C2443_CLKDIV0_ARMDIV_2 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]  = 2,
      [S3C2443_CLKDIV0_ARMDIV_3 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]  = 3,
      [S3C2443_CLKDIV0_ARMDIV_4 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]  = 4,
      [S3C2443_CLKDIV0_ARMDIV_6 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]  = 6,
      [S3C2443_CLKDIV0_ARMDIV_8 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]  = 8,
      [S3C2443_CLKDIV0_ARMDIV_12 >> S3C2443_CLKDIV0_ARMDIV_SHIFT] = 12,
      [S3C2443_CLKDIV0_ARMDIV_16 >> S3C2443_CLKDIV0_ARMDIV_SHIFT] = 16,
};

static inline unsigned int s3c2443_fclk_div(unsigned long clkcon0)
{
      clkcon0 &= S3C2443_CLKDIV0_ARMDIV_MASK;

      return armdiv[clkcon0 >> S3C2443_CLKDIV0_ARMDIV_SHIFT];
}

static unsigned long s3c2443_armclk_roundrate(struct clk *clk,
                                    unsigned long rate)
{
      unsigned long parent = clk_get_rate(clk->parent);
      unsigned long calc;
      unsigned best = 256; /* bigger than any value */
      unsigned div;
      int ptr;

      for (ptr = 0; ptr < ARRAY_SIZE(armdiv); ptr++) {
            div = armdiv[ptr];
            calc = parent / div;
            if (calc <= rate && div < best)
                  best = div;
      }

      return parent / best;
}

static int s3c2443_armclk_setrate(struct clk *clk, unsigned long rate)
{
      unsigned long parent = clk_get_rate(clk->parent);
      unsigned long calc;
      unsigned div;
      unsigned best = 256; /* bigger than any value */
      int ptr;
      int val = -1;

      for (ptr = 0; ptr < ARRAY_SIZE(armdiv); ptr++) {
            div = armdiv[ptr];
            calc = parent / div;
            if (calc <= rate && div < best) {
                  best = div;
                  val = ptr;
            }
      }

      if (val >= 0) {
            unsigned long clkcon0;

            clkcon0 = __raw_readl(S3C2443_CLKDIV0);
            clkcon0 &= S3C2443_CLKDIV0_ARMDIV_MASK;
            clkcon0 |= val << S3C2443_CLKDIV0_ARMDIV_SHIFT;
            __raw_writel(clkcon0, S3C2443_CLKDIV0);
      }

      return (val == -1) ? -EINVAL : 0;
}

static struct clk clk_armdiv = {
      .name       = "armdiv",
      .id         = -1,
      .parent           = &clk_msysclk.clk,
      .ops        = &(struct clk_ops) {
            .round_rate = s3c2443_armclk_roundrate,
            .set_rate = s3c2443_armclk_setrate,
      },
};

/* armclk
 *
 * this is the clock fed into the ARM core itself, from armdiv or from hclk.
 */

static struct clk *clk_arm_sources[] = {
      [0] = &clk_armdiv,
      [1] = &clk_h,
};

static struct clksrc_clk clk_arm = {
      .clk  = {
            .name       = "armclk",
            .id         = -1,
      },
      .sources = &(struct clksrc_sources) {
            .sources = clk_arm_sources,
            .nr_sources = ARRAY_SIZE(clk_arm_sources),
      },
      .reg_src = { .reg = S3C2443_CLKDIV0, .size = 1, .shift = 13 },
};

/* hsspi
 *
 * high-speed spi clock, sourced from esysclk
*/

static struct clksrc_clk clk_hsspi = {
      .clk  = {
            .name       = "hsspi",
            .id         = -1,
            .parent           = &clk_esysclk.clk,
            .ctrlbit    = S3C2443_SCLKCON_HSSPICLK,
            .enable           = s3c2443_clkcon_enable_s,
      },
      .reg_div = { .reg = S3C2443_CLKDIV1, .size = 2, .shift = 4 },
};


/* clk_hsmcc_div
 *
 * this clock is sourced from epll, and is fed through a divider,
 * to a mux controlled by sclkcon where either it or a extclk can
 * be fed to the hsmmc block
*/

static struct clksrc_clk clk_hsmmc_div = {
      .clk  = {
            .name       = "hsmmc-div",
            .id         = 1,
            .parent           = &clk_esysclk.clk,
      },
      .reg_div = { .reg = S3C2443_CLKDIV1, .size = 2, .shift = 6 },
};

static int s3c2443_setparent_hsmmc(struct clk *clk, struct clk *parent)
{
      unsigned long clksrc = __raw_readl(S3C2443_SCLKCON);

      clksrc &= ~(S3C2443_SCLKCON_HSMMCCLK_EXT |
                S3C2443_SCLKCON_HSMMCCLK_EPLL);

      if (parent == &clk_epll)
            clksrc |= S3C2443_SCLKCON_HSMMCCLK_EPLL;
      else if (parent == &clk_ext)
            clksrc |= S3C2443_SCLKCON_HSMMCCLK_EXT;
      else
            return -EINVAL;

      if (clk->usage > 0) {
            __raw_writel(clksrc, S3C2443_SCLKCON);
      }

      clk->parent = parent;
      return 0;
}

static int s3c2443_enable_hsmmc(struct clk *clk, int enable)
{
      return s3c2443_setparent_hsmmc(clk, clk->parent);
}

static struct clk clk_hsmmc = {
      .name       = "hsmmc-if",
      .id         = 1,
      .parent           = &clk_hsmmc_div.clk,
      .enable           = s3c2443_enable_hsmmc,
      .ops        = &(struct clk_ops) {
            .set_parent = s3c2443_setparent_hsmmc,
      },
};

/* i2s_eplldiv
 *
 * This clock is the output from the I2S divisor of ESYSCLK, and is separate
 * from the mux that comes after it (cannot merge into one single clock)
*/

static struct clksrc_clk clk_i2s_eplldiv = {
      .clk  = {
            .name       = "i2s-eplldiv",
            .id         = -1,
            .parent           = &clk_esysclk.clk,
      },
      .reg_div = { .reg = S3C2443_CLKDIV1, .size = 4, .shift = 12, },
};

/* i2s-ref
 *
 * i2s bus reference clock, selectable from external, esysclk or epllref
 *
 * Note, this used to be two clocks, but was compressed into one.
*/

struct clk *clk_i2s_srclist[] = {
      [0] = &clk_i2s_eplldiv.clk,
      [1] = &clk_i2s_ext,
      [2] = &clk_epllref.clk,
      [3] = &clk_epllref.clk,
};

static struct clksrc_clk clk_i2s = {
      .clk  = {
            .name       = "i2s-if",
            .id         = -1,
            .ctrlbit    = S3C2443_SCLKCON_I2SCLK,
            .enable           = s3c2443_clkcon_enable_s,

      },
      .sources = &(struct clksrc_sources) {
            .sources = clk_i2s_srclist,
            .nr_sources = ARRAY_SIZE(clk_i2s_srclist),
      },
      .reg_src = { .reg = S3C2443_CLKSRC, .size = 2, .shift = 14 },
};

/* standard clock definitions */

static struct clk init_clocks_off[] = {
      {
            .name       = "sdi",
            .id         = -1,
            .parent           = &clk_p,
            .enable           = s3c2443_clkcon_enable_p,
            .ctrlbit    = S3C2443_PCLKCON_SDI,
      }, {
            .name       = "iis",
            .id         = -1,
            .parent           = &clk_p,
            .enable           = s3c2443_clkcon_enable_p,
            .ctrlbit    = S3C2443_PCLKCON_IIS,
      }, {
            .name       = "spi",
            .id         = 0,
            .parent           = &clk_p,
            .enable           = s3c2443_clkcon_enable_p,
            .ctrlbit    = S3C2443_PCLKCON_SPI0,
      }, {
            .name       = "spi",
            .id         = 1,
            .parent           = &clk_p,
            .enable           = s3c2443_clkcon_enable_p,
            .ctrlbit    = S3C2443_PCLKCON_SPI1,
      }
};

static struct clk init_clocks[] = {
};

/* clocks to add straight away */

static struct clksrc_clk *clksrcs[] __initdata = {
      &clk_arm,
      &clk_i2s_eplldiv,
      &clk_i2s,
      &clk_hsspi,
      &clk_hsmmc_div,
};

static struct clk *clks[] __initdata = {
      &clk_hsmmc,
      &clk_armdiv,
};

void __init_or_cpufreq s3c2443_setup_clocks(void)
{
      s3c2443_common_setup_clocks(s3c2443_get_mpll, s3c2443_fclk_div);
}

void __init s3c2443_init_clocks(int xtal)
{
      unsigned long epllcon = __raw_readl(S3C2443_EPLLCON);
      int ptr;

      clk_epll.rate = s3c2443_get_epll(epllcon, xtal);
      clk_epll.parent = &clk_epllref.clk;

      s3c2443_common_init_clocks(xtal, s3c2443_get_mpll, s3c2443_fclk_div);

      s3c2443_setup_clocks();

      s3c24xx_register_clocks(clks, ARRAY_SIZE(clks));

      for (ptr = 0; ptr < ARRAY_SIZE(clksrcs); ptr++)
            s3c_register_clksrc(clksrcs[ptr], 1);

      /* register clocks from clock array */

      s3c_register_clocks(init_clocks, ARRAY_SIZE(init_clocks));

      /* We must be careful disabling the clocks we are not intending to
       * be using at boot time, as subsystems such as the LCD which do
       * their own DMA requests to the bus can cause the system to lockup
       * if they where in the middle of requesting bus access.
       *
       * Disabling the LCD clock if the LCD is active is very dangerous,
       * and therefore the bootloader should be careful to not enable
       * the LCD clock if it is not needed.
      */

      /* install (and disable) the clocks we do not need immediately */

      s3c_register_clocks(init_clocks_off, ARRAY_SIZE(init_clocks_off));
      s3c_disable_clocks(init_clocks_off, ARRAY_SIZE(init_clocks_off));

      s3c_pwmclk_init();
}

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