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mpc52xx_common.c

/*
 *
 * Utility functions for the Freescale MPC52xx.
 *
 * Copyright (C) 2006 Sylvain Munaut <tnt@246tNt.com>
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 *
 */

#undef DEBUG

#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/of_platform.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/mpc52xx.h>

/* MPC5200 device tree match tables */
static struct of_device_id mpc52xx_xlb_ids[] __initdata = {
      { .compatible = "fsl,mpc5200-xlb", },
      { .compatible = "mpc5200-xlb", },
      {}
};
static struct of_device_id mpc52xx_bus_ids[] __initdata = {
      { .compatible = "fsl,mpc5200-immr", },
      { .compatible = "fsl,mpc5200b-immr", },
      { .compatible = "fsl,lpb", },

      /* depreciated matches; shouldn't be used in new device trees */
      { .type = "builtin", .compatible = "mpc5200", }, /* efika */
      { .type = "soc", .compatible = "mpc5200", }, /* lite5200 */
      {}
};

/*
 * This variable is mapped in mpc52xx_map_wdt() and used in mpc52xx_restart().
 * Permanent mapping is required because mpc52xx_restart() can be called
 * from interrupt context while node mapping (which calls ioremap())
 * cannot be used at such point.
 */
static spinlock_t mpc52xx_lock = SPIN_LOCK_UNLOCKED;
static struct mpc52xx_gpt __iomem *mpc52xx_wdt;
static struct mpc52xx_cdm __iomem *mpc52xx_cdm;

/**
 *    mpc52xx_find_ipb_freq - Find the IPB bus frequency for a device
 *    @node:      device node
 *
 *    Returns IPB bus frequency, or 0 if the bus frequency cannot be found.
 */
unsigned int
mpc52xx_find_ipb_freq(struct device_node *node)
{
      struct device_node *np;
      const unsigned int *p_ipb_freq = NULL;

      of_node_get(node);
      while (node) {
            p_ipb_freq = of_get_property(node, "bus-frequency", NULL);
            if (p_ipb_freq)
                  break;

            np = of_get_parent(node);
            of_node_put(node);
            node = np;
      }
      if (node)
            of_node_put(node);

      return p_ipb_freq ? *p_ipb_freq : 0;
}
EXPORT_SYMBOL(mpc52xx_find_ipb_freq);


/*
 * Configure the XLB arbiter settings to match what Linux expects.
 */
void __init
mpc5200_setup_xlb_arbiter(void)
{
      struct device_node *np;
      struct mpc52xx_xlb  __iomem *xlb;

      np = of_find_matching_node(NULL, mpc52xx_xlb_ids);
      xlb = of_iomap(np, 0);
      of_node_put(np);
      if (!xlb) {
            printk(KERN_ERR __FILE__ ": "
                  "Error mapping XLB in mpc52xx_setup_cpu().  "
                  "Expect some abnormal behavior\n");
            return;
      }

      /* Configure the XLB Arbiter priorities */
      out_be32(&xlb->master_pri_enable, 0xff);
      out_be32(&xlb->master_priority, 0x11111111);

      /* Disable XLB pipelining
       * (cfr errate 292. We could do this only just before ATA PIO
       *  transaction and re-enable it afterwards ...)
       */
      out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS);

      iounmap(xlb);
}

/**
 * mpc52xx_declare_of_platform_devices: register internal devices and children
 *                            of the localplus bus to the of_platform
 *                            bus.
 */
void __init
mpc52xx_declare_of_platform_devices(void)
{
      /* Find every child of the SOC node and add it to of_platform */
      if (of_platform_bus_probe(NULL, mpc52xx_bus_ids, NULL))
            printk(KERN_ERR __FILE__ ": "
                  "Error while probing of_platform bus\n");
}

/*
 * match tables used by mpc52xx_map_common_devices()
 */
static struct of_device_id mpc52xx_gpt_ids[] __initdata = {
      { .compatible = "fsl,mpc5200-gpt", },
      { .compatible = "mpc5200-gpt", }, /* old */
      {}
};
static struct of_device_id mpc52xx_cdm_ids[] __initdata = {
      { .compatible = "fsl,mpc5200-cdm", },
      { .compatible = "mpc5200-cdm", }, /* old */
      {}
};

/**
 * mpc52xx_map_common_devices: iomap devices required by common code
 */
void __init
mpc52xx_map_common_devices(void)
{
      struct device_node *np;

      /* mpc52xx_wdt is mapped here and used in mpc52xx_restart,
       * possibly from a interrupt context. wdt is only implement
       * on a gpt0, so check has-wdt property before mapping.
       */
      for_each_matching_node(np, mpc52xx_gpt_ids) {
            if (of_get_property(np, "fsl,has-wdt", NULL) ||
                of_get_property(np, "has-wdt", NULL)) {
                  mpc52xx_wdt = of_iomap(np, 0);
                  of_node_put(np);
                  break;
            }
      }

      /* Clock Distribution Module, used by PSC clock setting function */
      np = of_find_matching_node(NULL, mpc52xx_cdm_ids);
      mpc52xx_cdm = of_iomap(np, 0);
      of_node_put(np);
}

/**
 * mpc52xx_set_psc_clkdiv: Set clock divider in the CDM for PSC ports
 *
 * @psc_id: id of psc port; must be 1,2,3 or 6
 * @clkdiv: clock divider value to put into CDM PSC register.
 */
int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv)
{
      unsigned long flags;
      u16 __iomem *reg;
      u32 val;
      u32 mask;
      u32 mclken_div;

      if (!mpc52xx_cdm)
            return -ENODEV;

      mclken_div = 0x8000 | (clkdiv & 0x1FF);
      switch (psc_id) {
      case 1: reg = &mpc52xx_cdm->mclken_div_psc1; mask = 0x20; break;
      case 2: reg = &mpc52xx_cdm->mclken_div_psc2; mask = 0x40; break;
      case 3: reg = &mpc52xx_cdm->mclken_div_psc3; mask = 0x80; break;
      case 6: reg = &mpc52xx_cdm->mclken_div_psc6; mask = 0x10; break;
      default:
            return -ENODEV;
      }

      /* Set the rate and enable the clock */
      spin_lock_irqsave(&mpc52xx_lock, flags);
      out_be16(reg, mclken_div);
      val = in_be32(&mpc52xx_cdm->clk_enables);
      out_be32(&mpc52xx_cdm->clk_enables, val | mask);
      spin_unlock_irqrestore(&mpc52xx_lock, flags);

      return 0;
}
EXPORT_SYMBOL(mpc52xx_set_psc_clkdiv);

/**
 * mpc52xx_restart: ppc_md->restart hook for mpc5200 using the watchdog timer
 */
void
mpc52xx_restart(char *cmd)
{
      local_irq_disable();

      /* Turn on the watchdog and wait for it to expire.
       * It effectively does a reset. */
      if (mpc52xx_wdt) {
            out_be32(&mpc52xx_wdt->mode, 0x00000000);
            out_be32(&mpc52xx_wdt->count, 0x000000ff);
            out_be32(&mpc52xx_wdt->mode, 0x00009004);
      } else
            printk("mpc52xx_restart: Can't access wdt. "
                  "Restart impossible, system halted.\n");

      while (1);
}

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