arch/powerpc/platforms/52xx/mpc52xx_common.c

   1 /*
   2  *
   3  * Utility functions for the Freescale MPC52xx.
   4  *
   5  * Copyright (C) 2006 Sylvain Munaut <tnt@246tNt.com>
   6  *
   7  * This file is licensed under the terms of the GNU General Public License
   8  * version 2. This program is licensed "as is" without any warranty of any
   9  * kind, whether express or implied.
  10  *
  11  */
  12
  13 #undef DEBUG
  14
  15 #include <linux/kernel.h>
  16 #include <linux/of_platform.h>
  17 #include <asm/io.h>
  18 #include <asm/prom.h>
  19 #include <asm/mpc52xx.h>
  20
  21 /*
  22  * This variable is mapped in mpc52xx_map_wdt() and used in mpc52xx_restart().
  23  * Permanent mapping is required because mpc52xx_restart() can be called
  24  * from interrupt context while node mapping (which calls ioremap())
  25  * cannot be used at such point.
  26  */
  27 static volatile struct mpc52xx_gpt *mpc52xx_wdt = NULL;
  28
  29 static void __iomem *
  30 mpc52xx_map_node(struct device_node *ofn)
  31 {
  32         const u32 *regaddr_p;
  33         u64 regaddr64, size64;
  34
  35         if (!ofn)
  36                 return NULL;
  37
  38         regaddr_p = of_get_address(ofn, 0, &size64, NULL);
  39         if (!regaddr_p) {
  40                 of_node_put(ofn);
  41                 return NULL;
  42         }
  43
  44         regaddr64 = of_translate_address(ofn, regaddr_p);
  45
  46         of_node_put(ofn);
  47
  48         return ioremap((u32)regaddr64, (u32)size64);
  49 }
  50
  51 void __iomem *
  52 mpc52xx_find_and_map(const char *compatible)
  53 {
  54         return mpc52xx_map_node(
  55                 of_find_compatible_node(NULL, NULL, compatible));
  56 }
  57
  58 EXPORT_SYMBOL(mpc52xx_find_and_map);
  59
  60 void __iomem *
  61 mpc52xx_find_and_map_path(const char *path)
  62 {
  63         return mpc52xx_map_node(of_find_node_by_path(path));
  64 }
  65
  66 EXPORT_SYMBOL(mpc52xx_find_and_map_path);
  67
  68 /**
  69  *      mpc52xx_find_ipb_freq - Find the IPB bus frequency for a device
  70  *      @node:  device node
  71  *
  72  *      Returns IPB bus frequency, or 0 if the bus frequency cannot be found.
  73  */
  74 unsigned int
  75 mpc52xx_find_ipb_freq(struct device_node *node)
  76 {
  77         struct device_node *np;
  78         const unsigned int *p_ipb_freq = NULL;
  79
  80         of_node_get(node);
  81         while (node) {
  82                 p_ipb_freq = of_get_property(node, "bus-frequency", NULL);
  83                 if (p_ipb_freq)
  84                         break;
  85
  86                 np = of_get_parent(node);
  87                 of_node_put(node);
  88                 node = np;
  89         }
  90         if (node)
  91                 of_node_put(node);
  92
  93         return p_ipb_freq ? *p_ipb_freq : 0;
  94 }
  95 EXPORT_SYMBOL(mpc52xx_find_ipb_freq);
  96
  97
  98 /*
  99  * Configure the XLB arbiter settings to match what Linux expects.
 100  */
 101 void __init
 102 mpc5200_setup_xlb_arbiter(void)
 103 {
 104         struct mpc52xx_xlb  __iomem *xlb;
 105
 106         xlb = mpc52xx_find_and_map("mpc5200-xlb");
 107         if (!xlb) {
 108                 printk(KERN_ERR __FILE__ ": "
 109                         "Error mapping XLB in mpc52xx_setup_cpu().  "
 110                         "Expect some abnormal behavior\n");
 111                 return;
 112         }
 113
 114         /* Configure the XLB Arbiter priorities */
 115         out_be32(&xlb->master_pri_enable, 0xff);
 116         out_be32(&xlb->master_priority, 0x11111111);
 117
 118         /* Disable XLB pipelining
 119          * (cfr errate 292. We could do this only just before ATA PIO
 120          *  transaction and re-enable it afterwards ...)
 121          */
 122         out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS);
 123
 124         iounmap(xlb);
 125 }
 126
 127 void __init
 128 mpc52xx_declare_of_platform_devices(void)
 129 {
 130         /* Find every child of the SOC node and add it to of_platform */
 131         if (of_platform_bus_probe(NULL, NULL, NULL))
 132                 printk(KERN_ERR __FILE__ ": "
 133                         "Error while probing of_platform bus\n");
 134 }
 135
 136 void __init
 137 mpc52xx_map_wdt(void)
 138 {
 139         const void *has_wdt;
 140         struct device_node *np;
 141
 142         /* mpc52xx_wdt is mapped here and used in mpc52xx_restart,
 143          * possibly from a interrupt context. wdt is only implement
 144          * on a gpt0, so check has-wdt property before mapping.
 145          */
 146         for_each_compatible_node(np, NULL, "fsl,mpc5200-gpt") {
 147                 has_wdt = of_get_property(np, "fsl,has-wdt", NULL);
 148                 if (has_wdt) {
 149                         mpc52xx_wdt = mpc52xx_map_node(np);
 150                         return;
 151                 }
 152         }
 153         for_each_compatible_node(np, NULL, "mpc5200-gpt") {
 154                 has_wdt = of_get_property(np, "has-wdt", NULL);
 155                 if (has_wdt) {
 156                         mpc52xx_wdt = mpc52xx_map_node(np);
 157                         return;
 158                 }
 159         }
 160 }
 161
 162 void
 163 mpc52xx_restart(char *cmd)
 164 {
 165         local_irq_disable();
 166
 167         /* Turn on the watchdog and wait for it to expire.
 168          * It effectively does a reset. */
 169         if (mpc52xx_wdt) {
 170                 out_be32(&mpc52xx_wdt->mode, 0x00000000);
 171                 out_be32(&mpc52xx_wdt->count, 0x000000ff);
 172                 out_be32(&mpc52xx_wdt->mode, 0x00009004);
 173         } else
 174                 printk("mpc52xx_restart: Can't access wdt. "
 175                         "Restart impossible, system halted.\n");
 176
 177         while (1);
 178 }