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/spinlock.h>
  17 #include <linux/of_platform.h>
  18 #include <asm/io.h>
  19 #include <asm/prom.h>
  20 #include <asm/mpc52xx.h>
  21
  22 /* MPC5200 device tree match tables */
  23 static struct of_device_id mpc52xx_xlb_ids[] __initdata = {
  24         { .compatible = "fsl,mpc5200-xlb", },
  25         { .compatible = "mpc5200-xlb", },
  26         {}
  27 };
  28 static struct of_device_id mpc52xx_bus_ids[] __initdata = {
  29         { .compatible = "fsl,mpc5200-immr", },
  30         { .compatible = "fsl,mpc5200b-immr", },
  31         { .compatible = "fsl,lpb", },
  32
  33         /* depreciated matches; shouldn't be used in new device trees */
  34         { .type = "builtin", .compatible = "mpc5200", }, /* efika */
  35         { .type = "soc", .compatible = "mpc5200", }, /* lite5200 */
  36         {}
  37 };
  38
  39 /*
  40  * This variable is mapped in mpc52xx_map_wdt() and used in mpc52xx_restart().
  41  * Permanent mapping is required because mpc52xx_restart() can be called
  42  * from interrupt context while node mapping (which calls ioremap())
  43  * cannot be used at such point.
  44  */
  45 static spinlock_t mpc52xx_lock = SPIN_LOCK_UNLOCKED;
  46 static struct mpc52xx_gpt __iomem *mpc52xx_wdt;
  47 static struct mpc52xx_cdm __iomem *mpc52xx_cdm;
  48
  49 /**
  50  *      mpc52xx_find_ipb_freq - Find the IPB bus frequency for a device
  51  *      @node:  device node
  52  *
  53  *      Returns IPB bus frequency, or 0 if the bus frequency cannot be found.
  54  */
  55 unsigned int
  56 mpc52xx_find_ipb_freq(struct device_node *node)
  57 {
  58         struct device_node *np;
  59         const unsigned int *p_ipb_freq = NULL;
  60
  61         of_node_get(node);
  62         while (node) {
  63                 p_ipb_freq = of_get_property(node, "bus-frequency", NULL);
  64                 if (p_ipb_freq)
  65                         break;
  66
  67                 np = of_get_parent(node);
  68                 of_node_put(node);
  69                 node = np;
  70         }
  71         if (node)
  72                 of_node_put(node);
  73
  74         return p_ipb_freq ? *p_ipb_freq : 0;
  75 }
  76 EXPORT_SYMBOL(mpc52xx_find_ipb_freq);
  77
  78
  79 /*
  80  * Configure the XLB arbiter settings to match what Linux expects.
  81  */
  82 void __init
  83 mpc5200_setup_xlb_arbiter(void)
  84 {
  85         struct device_node *np;
  86         struct mpc52xx_xlb  __iomem *xlb;
  87
  88         np = of_find_matching_node(NULL, mpc52xx_xlb_ids);
  89         xlb = of_iomap(np, 0);
  90         of_node_put(np);
  91         if (!xlb) {
  92                 printk(KERN_ERR __FILE__ ": "
  93                         "Error mapping XLB in mpc52xx_setup_cpu().  "
  94                         "Expect some abnormal behavior\n");
  95                 return;
  96         }
  97
  98         /* Configure the XLB Arbiter priorities */
  99         out_be32(&xlb->master_pri_enable, 0xff);
 100         out_be32(&xlb->master_priority, 0x11111111);
 101
 102         /* Disable XLB pipelining
 103          * (cfr errate 292. We could do this only just before ATA PIO
 104          *  transaction and re-enable it afterwards ...)
 105          */
 106         out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS);
 107
 108         iounmap(xlb);
 109 }
 110
 111 /**
 112  * mpc52xx_declare_of_platform_devices: register internal devices and children
 113  *                                      of the localplus bus to the of_platform
 114  *                                      bus.
 115  */
 116 void __init
 117 mpc52xx_declare_of_platform_devices(void)
 118 {
 119         /* Find every child of the SOC node and add it to of_platform */
 120         if (of_platform_bus_probe(NULL, mpc52xx_bus_ids, NULL))
 121                 printk(KERN_ERR __FILE__ ": "
 122                         "Error while probing of_platform bus\n");
 123 }
 124
 125 /*
 126  * match tables used by mpc52xx_map_common_devices()
 127  */
 128 static struct of_device_id mpc52xx_gpt_ids[] __initdata = {
 129         { .compatible = "fsl,mpc5200-gpt", },
 130         { .compatible = "mpc5200-gpt", }, /* old */
 131         {}
 132 };
 133 static struct of_device_id mpc52xx_cdm_ids[] __initdata = {
 134         { .compatible = "fsl,mpc5200-cdm", },
 135         { .compatible = "mpc5200-cdm", }, /* old */
 136         {}
 137 };
 138
 139 /**
 140  * mpc52xx_map_common_devices: iomap devices required by common code
 141  */
 142 void __init
 143 mpc52xx_map_common_devices(void)
 144 {
 145         struct device_node *np;
 146
 147         /* mpc52xx_wdt is mapped here and used in mpc52xx_restart,
 148          * possibly from a interrupt context. wdt is only implement
 149          * on a gpt0, so check has-wdt property before mapping.
 150          */
 151         for_each_matching_node(np, mpc52xx_gpt_ids) {
 152                 if (of_get_property(np, "fsl,has-wdt", NULL) ||
 153                     of_get_property(np, "has-wdt", NULL)) {
 154                         mpc52xx_wdt = of_iomap(np, 0);
 155                         of_node_put(np);
 156                         break;
 157                 }
 158         }
 159
 160         /* Clock Distribution Module, used by PSC clock setting function */
 161         np = of_find_matching_node(NULL, mpc52xx_cdm_ids);
 162         mpc52xx_cdm = of_iomap(np, 0);
 163         of_node_put(np);
 164 }
 165
 166 /**
 167  * mpc52xx_set_psc_clkdiv: Set clock divider in the CDM for PSC ports
 168  *
 169  * @psc_id: id of psc port; must be 1,2,3 or 6
 170  * @clkdiv: clock divider value to put into CDM PSC register.
 171  */
 172 int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv)
 173 {
 174         unsigned long flags;
 175         u16 __iomem *reg;
 176         u32 val;
 177         u32 mask;
 178         u32 mclken_div;
 179
 180         if (!mpc52xx_cdm)
 181                 return -ENODEV;
 182
 183         mclken_div = 0x8000 | (clkdiv & 0x1FF);
 184         switch (psc_id) {
 185         case 1: reg = &mpc52xx_cdm->mclken_div_psc1; mask = 0x20; break;
 186         case 2: reg = &mpc52xx_cdm->mclken_div_psc2; mask = 0x40; break;
 187         case 3: reg = &mpc52xx_cdm->mclken_div_psc3; mask = 0x80; break;
 188         case 6: reg = &mpc52xx_cdm->mclken_div_psc6; mask = 0x10; break;
 189         default:
 190                 return -ENODEV;
 191         }
 192
 193         /* Set the rate and enable the clock */
 194         spin_lock_irqsave(&mpc52xx_lock, flags);
 195         out_be16(reg, mclken_div);
 196         val = in_be32(&mpc52xx_cdm->clk_enables);
 197         out_be32(&mpc52xx_cdm->clk_enables, val | mask);
 198         spin_unlock_irqrestore(&mpc52xx_lock, flags);
 199
 200         return 0;
 201 }
 202 EXPORT_SYMBOL(mpc52xx_set_psc_clkdiv);
 203
 204 /**
 205  * mpc52xx_restart: ppc_md->restart hook for mpc5200 using the watchdog timer
 206  */
 207 void
 208 mpc52xx_restart(char *cmd)
 209 {
 210         local_irq_disable();
 211
 212         /* Turn on the watchdog and wait for it to expire.
 213          * It effectively does a reset. */
 214         if (mpc52xx_wdt) {
 215                 out_be32(&mpc52xx_wdt->mode, 0x00000000);
 216                 out_be32(&mpc52xx_wdt->count, 0x000000ff);
 217                 out_be32(&mpc52xx_wdt->mode, 0x00009004);
 218         } else
 219                 printk("mpc52xx_restart: Can't access wdt. "
 220                         "Restart impossible, system halted.\n");
 221
 222         while (1);
 223 }