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 = "simple-bus", },
  32
  33         /* depreciated matches; shouldn't be used in new device trees */
  34         { .compatible = "fsl,lpb", },
  35         { .type = "builtin", .compatible = "mpc5200", }, /* efika */
  36         { .type = "soc", .compatible = "mpc5200", }, /* lite5200 */
  37         {}
  38 };
  39
  40 /*
  41  * This variable is mapped in mpc52xx_map_wdt() and used in mpc52xx_restart().
  42  * Permanent mapping is required because mpc52xx_restart() can be called
  43  * from interrupt context while node mapping (which calls ioremap())
  44  * cannot be used at such point.
  45  */
  46 static DEFINE_SPINLOCK(mpc52xx_lock);
  47 static struct mpc52xx_gpt __iomem *mpc52xx_wdt;
  48 static struct mpc52xx_cdm __iomem *mpc52xx_cdm;
  49
  50 /*
  51  * Configure the XLB arbiter settings to match what Linux expects.
  52  */
  53 void __init
  54 mpc5200_setup_xlb_arbiter(void)
  55 {
  56         struct device_node *np;
  57         struct mpc52xx_xlb  __iomem *xlb;
  58
  59         np = of_find_matching_node(NULL, mpc52xx_xlb_ids);
  60         xlb = of_iomap(np, 0);
  61         of_node_put(np);
  62         if (!xlb) {
  63                 printk(KERN_ERR __FILE__ ": "
  64                         "Error mapping XLB in mpc52xx_setup_cpu(). "
  65                         "Expect some abnormal behavior\n");
  66                 return;
  67         }
  68
  69         /* Configure the XLB Arbiter priorities */
  70         out_be32(&xlb->master_pri_enable, 0xff);
  71         out_be32(&xlb->master_priority, 0x11111111);
  72
  73         /*
  74          * Disable XLB pipelining
  75          * (cfr errate 292. We could do this only just before ATA PIO
  76          *  transaction and re-enable it afterwards ...)
  77          * Not needed on MPC5200B.
  78          */
  79         if ((mfspr(SPRN_SVR) & MPC5200_SVR_MASK) == MPC5200_SVR)
  80                 out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS);
  81
  82         iounmap(xlb);
  83 }
  84
  85 /**
  86  * mpc52xx_declare_of_platform_devices: register internal devices and children
  87  *                                      of the localplus bus to the of_platform
  88  *                                      bus.
  89  */
  90 void __init
  91 mpc52xx_declare_of_platform_devices(void)
  92 {
  93         /* Find every child of the SOC node and add it to of_platform */
  94         if (of_platform_bus_probe(NULL, mpc52xx_bus_ids, NULL))
  95                 printk(KERN_ERR __FILE__ ": "
  96                         "Error while probing of_platform bus\n");
  97 }
  98
  99 /*
 100  * match tables used by mpc52xx_map_common_devices()
 101  */
 102 static struct of_device_id mpc52xx_gpt_ids[] __initdata = {
 103         { .compatible = "fsl,mpc5200-gpt", },
 104         { .compatible = "mpc5200-gpt", }, /* old */
 105         {}
 106 };
 107 static struct of_device_id mpc52xx_cdm_ids[] __initdata = {
 108         { .compatible = "fsl,mpc5200-cdm", },
 109         { .compatible = "mpc5200-cdm", }, /* old */
 110         {}
 111 };
 112
 113 /**
 114  * mpc52xx_map_common_devices: iomap devices required by common code
 115  */
 116 void __init
 117 mpc52xx_map_common_devices(void)
 118 {
 119         struct device_node *np;
 120
 121         /* mpc52xx_wdt is mapped here and used in mpc52xx_restart,
 122          * possibly from a interrupt context. wdt is only implement
 123          * on a gpt0, so check has-wdt property before mapping.
 124          */
 125         for_each_matching_node(np, mpc52xx_gpt_ids) {
 126                 if (of_get_property(np, "fsl,has-wdt", NULL) ||
 127                     of_get_property(np, "has-wdt", NULL)) {
 128                         mpc52xx_wdt = of_iomap(np, 0);
 129                         of_node_put(np);
 130                         break;
 131                 }
 132         }
 133
 134         /* Clock Distribution Module, used by PSC clock setting function */
 135         np = of_find_matching_node(NULL, mpc52xx_cdm_ids);
 136         mpc52xx_cdm = of_iomap(np, 0);
 137         of_node_put(np);
 138 }
 139
 140 /**
 141  * mpc52xx_set_psc_clkdiv: Set clock divider in the CDM for PSC ports
 142  *
 143  * @psc_id: id of psc port; must be 1,2,3 or 6
 144  * @clkdiv: clock divider value to put into CDM PSC register.
 145  */
 146 int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv)
 147 {
 148         unsigned long flags;
 149         u16 __iomem *reg;
 150         u32 val;
 151         u32 mask;
 152         u32 mclken_div;
 153
 154         if (!mpc52xx_cdm)
 155                 return -ENODEV;
 156
 157         mclken_div = 0x8000 | (clkdiv & 0x1FF);
 158         switch (psc_id) {
 159         case 1: reg = &mpc52xx_cdm->mclken_div_psc1; mask = 0x20; break;
 160         case 2: reg = &mpc52xx_cdm->mclken_div_psc2; mask = 0x40; break;
 161         case 3: reg = &mpc52xx_cdm->mclken_div_psc3; mask = 0x80; break;
 162         case 6: reg = &mpc52xx_cdm->mclken_div_psc6; mask = 0x10; break;
 163         default:
 164                 return -ENODEV;
 165         }
 166
 167         /* Set the rate and enable the clock */
 168         spin_lock_irqsave(&mpc52xx_lock, flags);
 169         out_be16(reg, mclken_div);
 170         val = in_be32(&mpc52xx_cdm->clk_enables);
 171         out_be32(&mpc52xx_cdm->clk_enables, val | mask);
 172         spin_unlock_irqrestore(&mpc52xx_lock, flags);
 173
 174         return 0;
 175 }
 176 EXPORT_SYMBOL(mpc52xx_set_psc_clkdiv);
 177
 178 /**
 179  * mpc52xx_get_xtal_freq - Get SYS_XTAL_IN frequency for a device
 180  *
 181  * @node: device node
 182  *
 183  * Returns the frequency of the external oscillator clock connected
 184  * to the SYS_XTAL_IN pin, or 0 if it cannot be determined.
 185  */
 186 unsigned int mpc52xx_get_xtal_freq(struct device_node *node)
 187 {
 188         u32 val;
 189         unsigned int freq;
 190
 191         if (!mpc52xx_cdm)
 192                 return 0;
 193
 194         freq = mpc5xxx_get_bus_frequency(node);
 195         if (!freq)
 196                 return 0;
 197
 198         if (in_8(&mpc52xx_cdm->ipb_clk_sel) & 0x1)
 199                 freq *= 2;
 200
 201         val  = in_be32(&mpc52xx_cdm->rstcfg);
 202         if (val & (1 << 5))
 203                 freq *= 8;
 204         else
 205                 freq *= 4;
 206         if (val & (1 << 6))
 207                 freq /= 12;
 208         else
 209                 freq /= 16;
 210
 211         return freq;
 212 }
 213 EXPORT_SYMBOL(mpc52xx_get_xtal_freq);
 214
 215 /**
 216  * mpc52xx_restart: ppc_md->restart hook for mpc5200 using the watchdog timer
 217  */
 218 void
 219 mpc52xx_restart(char *cmd)
 220 {
 221         local_irq_disable();
 222
 223         /* Turn on the watchdog and wait for it to expire.
 224          * It effectively does a reset. */
 225         if (mpc52xx_wdt) {
 226                 out_be32(&mpc52xx_wdt->mode, 0x00000000);
 227                 out_be32(&mpc52xx_wdt->count, 0x000000ff);
 228                 out_be32(&mpc52xx_wdt->mode, 0x00009004);
 229         } else
 230                 printk(KERN_ERR __FILE__ ": "
 231                         "mpc52xx_restart: Can't access wdt. "
 232                         "Restart impossible, system halted.\n");
 233
 234         while (1);
 235 }