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clock.c

/*
 * Copyright (C) 2007,2008 Freescale Semiconductor, Inc. All rights reserved.
 *
 * Author: John Rigby <jrigby@freescale.com>
 *
 * Implements the clk api defined in include/linux/clk.h
 *
 *    Original based on linux/arch/arm/mach-integrator/clock.c
 *
 *    Copyright (C) 2004 ARM Limited.
 *    Written by Deep Blue Solutions Limited.
 *
 * 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.
 */
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/clk.h>
#include <linux/mutex.h>
#include <linux/io.h>

#include <linux/of_platform.h>
#include <asm/mpc512x.h>
#include <asm/clk_interface.h>

#undef CLK_DEBUG

static int clocks_initialized;

#define CLK_HAS_RATE    0x1   /* has rate in MHz */
#define CLK_HAS_CTRL    0x2   /* has control reg and bit */

struct clk {
      struct list_head node;
      char name[32];
      int flags;
      struct device *dev;
      unsigned long rate;
      struct module *owner;
      void (*calc) (struct clk *);
      struct clk *parent;
      int reg, bit;           /* CLK_HAS_CTRL */
      int div_shift;          /* only used by generic_div_clk_calc */
};

static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);

static struct clk *mpc5121_clk_get(struct device *dev, const char *id)
{
      struct clk *p, *clk = ERR_PTR(-ENOENT);
      int dev_match = 0;
      int id_match = 0;

      if (dev == NULL && id == NULL)
            return NULL;

      mutex_lock(&clocks_mutex);
      list_for_each_entry(p, &clocks, node) {
            if (dev && dev == p->dev)
                  dev_match++;
            if (strcmp(id, p->name) == 0)
                  id_match++;
            if ((dev_match || id_match) && try_module_get(p->owner)) {
                  clk = p;
                  break;
            }
      }
      mutex_unlock(&clocks_mutex);

      return clk;
}

#ifdef CLK_DEBUG
static void dump_clocks(void)
{
      struct clk *p;

      mutex_lock(&clocks_mutex);
      printk(KERN_INFO "CLOCKS:\n");
      list_for_each_entry(p, &clocks, node) {
            printk(KERN_INFO "  %s %ld", p->name, p->rate);
            if (p->parent)
                  printk(KERN_INFO " %s %ld", p->parent->name,
                         p->parent->rate);
            if (p->flags & CLK_HAS_CTRL)
                  printk(KERN_INFO " reg/bit %d/%d", p->reg, p->bit);
            printk("\n");
      }
      mutex_unlock(&clocks_mutex);
}
#define     DEBUG_CLK_DUMP() dump_clocks()
#else
#define     DEBUG_CLK_DUMP()
#endif


static void mpc5121_clk_put(struct clk *clk)
{
      module_put(clk->owner);
}

#define NRPSC 12

00109 struct mpc512x_clockctl {
      u32 spmr;         /* System PLL Mode Reg */
      u32 sccr[2];            /* System Clk Ctrl Reg 1 & 2 */
      u32 scfr1;        /* System Clk Freq Reg 1 */
      u32 scfr2;        /* System Clk Freq Reg 2 */
      u32 reserved;
      u32 bcr;          /* Bread Crumb Reg */
      u32 pccr[NRPSC];  /* PSC Clk Ctrl Reg 0-11 */
      u32 spccr;        /* SPDIF Clk Ctrl Reg */
      u32 cccr;         /* CFM Clk Ctrl Reg */
      u32 dccr;         /* DIU Clk Cnfg Reg */
};

struct mpc512x_clockctl __iomem *clockctl;

static int mpc5121_clk_enable(struct clk *clk)
{
      unsigned int mask;

      if (clk->flags & CLK_HAS_CTRL) {
            mask = in_be32(&clockctl->sccr[clk->reg]);
            mask |= 1 << clk->bit;
            out_be32(&clockctl->sccr[clk->reg], mask);
      }
      return 0;
}

static void mpc5121_clk_disable(struct clk *clk)
{
      unsigned int mask;

      if (clk->flags & CLK_HAS_CTRL) {
            mask = in_be32(&clockctl->sccr[clk->reg]);
            mask &= ~(1 << clk->bit);
            out_be32(&clockctl->sccr[clk->reg], mask);
      }
}

static unsigned long mpc5121_clk_get_rate(struct clk *clk)
{
      if (clk->flags & CLK_HAS_RATE)
            return clk->rate;
      else
            return 0;
}

static long mpc5121_clk_round_rate(struct clk *clk, unsigned long rate)
{
      return rate;
}

static int mpc5121_clk_set_rate(struct clk *clk, unsigned long rate)
{
      return 0;
}

static int clk_register(struct clk *clk)
{
      mutex_lock(&clocks_mutex);
      list_add(&clk->node, &clocks);
      mutex_unlock(&clocks_mutex);
      return 0;
}

static unsigned long spmf_mult(void)
{
      /*
       * Convert spmf to multiplier
       */
      static int spmf_to_mult[] = {
            68, 1, 12, 16,
            20, 24, 28, 32,
            36, 40, 44, 48,
            52, 56, 60, 64
      };
      int spmf = (clockctl->spmr >> 24) & 0xf;
      return spmf_to_mult[spmf];
}

static unsigned long sysdiv_div_x_2(void)
{
      /*
       * Convert sysdiv to divisor x 2
       * Some divisors have fractional parts so
       * multiply by 2 then divide by this value
       */
      static int sysdiv_to_div_x_2[] = {
            4, 5, 6, 7,
            8, 9, 10, 14,
            12, 16, 18, 22,
            20, 24, 26, 30,
            28, 32, 34, 38,
            36, 40, 42, 46,
            44, 48, 50, 54,
            52, 56, 58, 62,
            60, 64, 66,
      };
      int sysdiv = (clockctl->scfr2 >> 26) & 0x3f;
      return sysdiv_to_div_x_2[sysdiv];
}

static unsigned long ref_to_sys(unsigned long rate)
{
      rate *= spmf_mult();
      rate *= 2;
      rate /= sysdiv_div_x_2();

      return rate;
}

static unsigned long sys_to_ref(unsigned long rate)
{
      rate *= sysdiv_div_x_2();
      rate /= 2;
      rate /= spmf_mult();

      return rate;
}

static long ips_to_ref(unsigned long rate)
{
      int ips_div = (clockctl->scfr1 >> 23) & 0x7;

      rate *= ips_div;  /* csb_clk = ips_clk * ips_div */
      rate *= 2;        /* sys_clk = csb_clk * 2 */
      return sys_to_ref(rate);
}

static unsigned long devtree_getfreq(char *clockname)
{
      struct device_node *np;
      const unsigned int *prop;
      unsigned int val = 0;

      np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-immr");
      if (np) {
            prop = of_get_property(np, clockname, NULL);
            if (prop)
                  val = *prop;
          of_node_put(np);
      }
      return val;
}

static void ref_clk_calc(struct clk *clk)
{
      unsigned long rate;

      rate = devtree_getfreq("bus-frequency");
      if (rate == 0) {
            printk(KERN_ERR "No bus-frequency in dev tree\n");
            clk->rate = 0;
            return;
      }
      clk->rate = ips_to_ref(rate);
}

static struct clk ref_clk = {
      .name = "ref_clk",
      .calc = ref_clk_calc,
};


static void sys_clk_calc(struct clk *clk)
{
      clk->rate = ref_to_sys(ref_clk.rate);
}

static struct clk sys_clk = {
      .name = "sys_clk",
      .calc = sys_clk_calc,
};

static void diu_clk_calc(struct clk *clk)
{
      int diudiv_x_2 = clockctl->scfr1 & 0xff;
      unsigned long rate;

      rate = sys_clk.rate;

      rate *= 2;
      rate /= diudiv_x_2;

      clk->rate = rate;
}

static void half_clk_calc(struct clk *clk)
{
      clk->rate = clk->parent->rate / 2;
}

static void generic_div_clk_calc(struct clk *clk)
{
      int div = (clockctl->scfr1 >> clk->div_shift) & 0x7;

      clk->rate = clk->parent->rate / div;
}

static void unity_clk_calc(struct clk *clk)
{
      clk->rate = clk->parent->rate;
}

static struct clk csb_clk = {
      .name = "csb_clk",
      .calc = half_clk_calc,
      .parent = &sys_clk,
};

static void e300_clk_calc(struct clk *clk)
{
      int spmf = (clockctl->spmr >> 16) & 0xf;
      int ratex2 = clk->parent->rate * spmf;

      clk->rate = ratex2 / 2;
}

static struct clk e300_clk = {
      .name = "e300_clk",
      .calc = e300_clk_calc,
      .parent = &csb_clk,
};

static struct clk ips_clk = {
      .name = "ips_clk",
      .calc = generic_div_clk_calc,
      .parent = &csb_clk,
      .div_shift = 23,
};

/*
 * Clocks controlled by SCCR1 (.reg = 0)
 */
static struct clk lpc_clk = {
      .name = "lpc_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 0,
      .bit = 30,
      .calc = generic_div_clk_calc,
      .parent = &ips_clk,
      .div_shift = 11,
};

static struct clk nfc_clk = {
      .name = "nfc_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 0,
      .bit = 29,
      .calc = generic_div_clk_calc,
      .parent = &ips_clk,
      .div_shift = 8,
};

static struct clk pata_clk = {
      .name = "pata_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 0,
      .bit = 28,
      .calc = unity_clk_calc,
      .parent = &ips_clk,
};

/*
 * PSC clocks (bits 27 - 16)
 * are setup elsewhere
 */

static struct clk sata_clk = {
      .name = "sata_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 0,
      .bit = 14,
      .calc = unity_clk_calc,
      .parent = &ips_clk,
};

static struct clk fec_clk = {
      .name = "fec_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 0,
      .bit = 13,
      .calc = unity_clk_calc,
      .parent = &ips_clk,
};

static struct clk pci_clk = {
      .name = "pci_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 0,
      .bit = 11,
      .calc = generic_div_clk_calc,
      .parent = &csb_clk,
      .div_shift = 20,
};

/*
 * Clocks controlled by SCCR2 (.reg = 1)
 */
static struct clk diu_clk = {
      .name = "diu_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 31,
      .calc = diu_clk_calc,
};

static struct clk axe_clk = {
      .name = "axe_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 30,
      .calc = unity_clk_calc,
      .parent = &csb_clk,
};

static struct clk usb1_clk = {
      .name = "usb1_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 28,
      .calc = unity_clk_calc,
      .parent = &csb_clk,
};

static struct clk usb2_clk = {
      .name = "usb2_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 27,
      .calc = unity_clk_calc,
      .parent = &csb_clk,
};

static struct clk i2c_clk = {
      .name = "i2c_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 26,
      .calc = unity_clk_calc,
      .parent = &ips_clk,
};

static struct clk mscan_clk = {
      .name = "mscan_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 25,
      .calc = unity_clk_calc,
      .parent = &ips_clk,
};

static struct clk sdhc_clk = {
      .name = "sdhc_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 24,
      .calc = unity_clk_calc,
      .parent = &ips_clk,
};

static struct clk mbx_bus_clk = {
      .name = "mbx_bus_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 22,
      .calc = half_clk_calc,
      .parent = &csb_clk,
};

static struct clk mbx_clk = {
      .name = "mbx_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 21,
      .calc = unity_clk_calc,
      .parent = &csb_clk,
};

static struct clk mbx_3d_clk = {
      .name = "mbx_3d_clk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 20,
      .calc = generic_div_clk_calc,
      .parent = &mbx_bus_clk,
      .div_shift = 14,
};

static void psc_mclk_in_calc(struct clk *clk)
{
      clk->rate = devtree_getfreq("psc_mclk_in");
      if (!clk->rate)
            clk->rate = 25000000;
}

static struct clk psc_mclk_in = {
      .name = "psc_mclk_in",
      .calc = psc_mclk_in_calc,
};

static struct clk spdif_txclk = {
      .name = "spdif_txclk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 23,
};

static struct clk spdif_rxclk = {
      .name = "spdif_rxclk",
      .flags = CLK_HAS_CTRL,
      .reg = 1,
      .bit = 23,
};

static void ac97_clk_calc(struct clk *clk)
{
      /* ac97 bit clock is always 24.567 MHz */
      clk->rate = 24567000;
}

static struct clk ac97_clk = {
      .name = "ac97_clk_in",
      .calc = ac97_clk_calc,
};

struct clk *rate_clks[] = {
      &ref_clk,
      &sys_clk,
      &diu_clk,
      &csb_clk,
      &e300_clk,
      &ips_clk,
      &fec_clk,
      &sata_clk,
      &pata_clk,
      &nfc_clk,
      &lpc_clk,
      &mbx_bus_clk,
      &mbx_clk,
      &mbx_3d_clk,
      &axe_clk,
      &usb1_clk,
      &usb2_clk,
      &i2c_clk,
      &mscan_clk,
      &sdhc_clk,
      &pci_clk,
      &psc_mclk_in,
      &spdif_txclk,
      &spdif_rxclk,
      &ac97_clk,
      NULL
};

static void rate_clk_init(struct clk *clk)
{
      if (clk->calc) {
            clk->calc(clk);
            clk->flags |= CLK_HAS_RATE;
            clk_register(clk);
      } else {
            printk(KERN_WARNING
                   "Could not initialize clk %s without a calc routine\n",
                   clk->name);
      }
}

static void rate_clks_init(void)
{
      struct clk **cpp, *clk;

      cpp = rate_clks;
      while ((clk = *cpp++))
            rate_clk_init(clk);
}

/*
 * There are two clk enable registers with 32 enable bits each
 * psc clocks and device clocks are all stored in dev_clks
 */
struct clk dev_clks[2][32];

/*
 * Given a psc number return the dev_clk
 * associated with it
 */
static struct clk *psc_dev_clk(int pscnum)
{
      int reg, bit;
      struct clk *clk;

      reg = 0;
      bit = 27 - pscnum;

      clk = &dev_clks[reg][bit];
      clk->reg = 0;
      clk->bit = bit;
      return clk;
}

/*
 * PSC clock rate calculation
 */
static void psc_calc_rate(struct clk *clk, int pscnum, struct device_node *np)
{
      unsigned long mclk_src = sys_clk.rate;
      unsigned long mclk_div;

      /*
       * Can only change value of mclk divider
       * when the divider is disabled.
       *
       * Zero is not a valid divider so minimum
       * divider is 1
       *
       * disable/set divider/enable
       */
      out_be32(&clockctl->pccr[pscnum], 0);
      out_be32(&clockctl->pccr[pscnum], 0x00020000);
      out_be32(&clockctl->pccr[pscnum], 0x00030000);

      if (clockctl->pccr[pscnum] & 0x80) {
            clk->rate = spdif_rxclk.rate;
            return;
      }

      switch ((clockctl->pccr[pscnum] >> 14) & 0x3) {
      case 0:
            mclk_src = sys_clk.rate;
            break;
      case 1:
            mclk_src = ref_clk.rate;
            break;
      case 2:
            mclk_src = psc_mclk_in.rate;
            break;
      case 3:
            mclk_src = spdif_txclk.rate;
            break;
      }

      mclk_div = ((clockctl->pccr[pscnum] >> 17) & 0x7fff) + 1;
      clk->rate = mclk_src / mclk_div;
}

/*
 * Find all psc nodes in device tree and assign a clock
 * with name "psc%d_mclk" and dev pointing at the device
 * returned from of_find_device_by_node
 */
static void psc_clks_init(void)
{
      struct device_node *np;
      const u32 *cell_index;
      struct of_device *ofdev;

      for_each_compatible_node(np, NULL, "fsl,mpc5121-psc") {
            cell_index = of_get_property(np, "cell-index", NULL);
            if (cell_index) {
                  int pscnum = *cell_index;
                  struct clk *clk = psc_dev_clk(pscnum);

                  clk->flags = CLK_HAS_RATE | CLK_HAS_CTRL;
                  ofdev = of_find_device_by_node(np);
                  clk->dev = &ofdev->dev;
                  /*
                   * AC97 is special rate clock does
                   * not go through normal path
                   */
                  if (strcmp("ac97", np->name) == 0)
                        clk->rate = ac97_clk.rate;
                  else
                        psc_calc_rate(clk, pscnum, np);
                  sprintf(clk->name, "psc%d_mclk", pscnum);
                  clk_register(clk);
                  clk_enable(clk);
            }
      }
}

static struct clk_interface mpc5121_clk_functions = {
      .clk_get          = mpc5121_clk_get,
      .clk_enable       = mpc5121_clk_enable,
      .clk_disable            = mpc5121_clk_disable,
      .clk_get_rate           = mpc5121_clk_get_rate,
      .clk_put          = mpc5121_clk_put,
      .clk_round_rate         = mpc5121_clk_round_rate,
      .clk_set_rate           = mpc5121_clk_set_rate,
      .clk_set_parent         = NULL,
      .clk_get_parent         = NULL,
};

static int
mpc5121_clk_init(void)
{
      struct device_node *np;

      np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-clock");
      if (np) {
            clockctl = of_iomap(np, 0);
            of_node_put(np);
      }

      if (!clockctl) {
            printk(KERN_ERR "Could not map clock control registers\n");
            return 0;
      }

      rate_clks_init();
      psc_clks_init();

      /* leave clockctl mapped forever */
      /*iounmap(clockctl); */
      DEBUG_CLK_DUMP();
      clocks_initialized++;
      clk_functions = mpc5121_clk_functions;
      return 0;
}


arch_initcall(mpc5121_clk_init);

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