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  *      mpc52xx_find_ipb_freq - Find the IPB bus frequency for a device
  52  *      @node:  device node
  53  *
  54  *      Returns IPB bus frequency, or 0 if the bus frequency cannot be found.
  55  */
  56 unsigned int
  57 mpc52xx_find_ipb_freq(struct device_node *node)
  58 {
  59         struct device_node *np;
  60         const unsigned int *p_ipb_freq = NULL;
  61
  62         of_node_get(node);
  63         while (node) {
  64                 p_ipb_freq = of_get_property(node, "bus-frequency", NULL);
  65                 if (p_ipb_freq)
  66                         break;
  67
  68                 np = of_get_parent(node);
  69                 of_node_put(node);
  70                 node = np;
  71         }
  72         if (node)
  73                 of_node_put(node);
  74
  75         return p_ipb_freq ? *p_ipb_freq : 0;
  76 }
  77 EXPORT_SYMBOL(mpc52xx_find_ipb_freq);
  78
  79
  80 /*
  81  * Configure the XLB arbiter settings to match what Linux expects.
  82  */
  83 void __init
  84 mpc5200_setup_xlb_arbiter(void)
  85 {
  86         struct device_node *np;
  87         struct mpc52xx_xlb  __iomem *xlb;
  88
  89         np = of_find_matching_node(NULL, mpc52xx_xlb_ids);
  90         xlb = of_iomap(np, 0);
  91         of_node_put(np);
  92         if (!xlb) {
  93                 printk(KERN_ERR __FILE__ ": "
  94                         "Error mapping XLB in mpc52xx_setup_cpu(). "
  95                         "Expect some abnormal behavior\n");
  96                 return;
  97         }
  98
  99         /* Configure the XLB Arbiter priorities */
 100         out_be32(&xlb->master_pri_enable, 0xff);
 101         out_be32(&xlb->master_priority, 0x11111111);
 102
 103         /*
 104          * Disable XLB pipelining
 105          * (cfr errate 292. We could do this only just before ATA PIO
 106          *  transaction and re-enable it afterwards ...)
 107          * Not needed on MPC5200B.
 108          */
 109         if ((mfspr(SPRN_SVR) & MPC5200_SVR_MASK) == MPC5200_SVR)
 110                 out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS);
 111
 112         iounmap(xlb);
 113 }
 114
 115 /**
 116  * mpc52xx_declare_of_platform_devices: register internal devices and children
 117  *                                      of the localplus bus to the of_platform
 118  *                                      bus.
 119  */
 120 void __init
 121 mpc52xx_declare_of_platform_devices(void)
 122 {
 123         /* Find every child of the SOC node and add it to of_platform */
 124         if (of_platform_bus_probe(NULL, mpc52xx_bus_ids, NULL))
 125                 printk(KERN_ERR __FILE__ ": "
 126                         "Error while probing of_platform bus\n");
 127 }
 128
 129 /*
 130  * match tables used by mpc52xx_map_common_devices()
 131  */
 132 static struct of_device_id mpc52xx_gpt_ids[] __initdata = {
 133         { .compatible = "fsl,mpc5200-gpt", },
 134         { .compatible = "mpc5200-gpt", }, /* old */
 135         {}
 136 };
 137 static struct of_device_id mpc52xx_cdm_ids[] __initdata = {
 138         { .compatible = "fsl,mpc5200-cdm", },
 139         { .compatible = "mpc5200-cdm", }, /* old */
 140         {}
 141 };
 142
 143 /**
 144  * mpc52xx_map_common_devices: iomap devices required by common code
 145  */
 146 void __init
 147 mpc52xx_map_common_devices(void)
 148 {
 149         struct device_node *np;
 150
 151         /* mpc52xx_wdt is mapped here and used in mpc52xx_restart,
 152          * possibly from a interrupt context. wdt is only implement
 153          * on a gpt0, so check has-wdt property before mapping.
 154          */
 155         for_each_matching_node(np, mpc52xx_gpt_ids) {
 156                 if (of_get_property(np, "fsl,has-wdt", NULL) ||
 157                     of_get_property(np, "has-wdt", NULL)) {
 158                         mpc52xx_wdt = of_iomap(np, 0);
 159                         of_node_put(np);
 160                         break;
 161                 }
 162         }
 163
 164         /* Clock Distribution Module, used by PSC clock setting function */
 165         np = of_find_matching_node(NULL, mpc52xx_cdm_ids);
 166         mpc52xx_cdm = of_iomap(np, 0);
 167         of_node_put(np);
 168 }
 169
 170 /**
 171  * mpc52xx_set_psc_clkdiv: Set clock divider in the CDM for PSC ports
 172  *
 173  * @psc_id: id of psc port; must be 1,2,3 or 6
 174  * @clkdiv: clock divider value to put into CDM PSC register.
 175  */
 176 int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv)
 177 {
 178         unsigned long flags;
 179         u16 __iomem *reg;
 180         u32 val;
 181         u32 mask;
 182         u32 mclken_div;
 183
 184         if (!mpc52xx_cdm)
 185                 return -ENODEV;
 186
 187         mclken_div = 0x8000 | (clkdiv & 0x1FF);
 188         switch (psc_id) {
 189         case 1: reg = &mpc52xx_cdm->mclken_div_psc1; mask = 0x20; break;
 190         case 2: reg = &mpc52xx_cdm->mclken_div_psc2; mask = 0x40; break;
 191         case 3: reg = &mpc52xx_cdm->mclken_div_psc3; mask = 0x80; break;
 192         case 6: reg = &mpc52xx_cdm->mclken_div_psc6; mask = 0x10; break;
 193         default:
 194                 return -ENODEV;
 195         }
 196
 197         /* Set the rate and enable the clock */
 198         spin_lock_irqsave(&mpc52xx_lock, flags);
 199         out_be16(reg, mclken_div);
 200         val = in_be32(&mpc52xx_cdm->clk_enables);
 201         out_be32(&mpc52xx_cdm->clk_enables, val | mask);
 202         spin_unlock_irqrestore(&mpc52xx_lock, flags);
 203
 204         return 0;
 205 }
 206 EXPORT_SYMBOL(mpc52xx_set_psc_clkdiv);
 207
 208 /**
 209  * mpc52xx_get_xtal_freq - Get SYS_XTAL_IN frequency for a device
 210  *
 211  * @node: device node
 212  *
 213  * Returns the frequency of the external oscillator clock connected
 214  * to the SYS_XTAL_IN pin, or 0 if it cannot be determined.
 215  */
 216 unsigned int mpc52xx_get_xtal_freq(struct device_node *node)
 217 {
 218         u32 val;
 219         unsigned int freq;
 220
 221         if (!mpc52xx_cdm)
 222                 return 0;
 223
 224         freq = mpc52xx_find_ipb_freq(node);
 225         if (!freq)
 226                 return 0;
 227
 228         if (in_8(&mpc52xx_cdm->ipb_clk_sel) & 0x1)
 229                 freq *= 2;
 230
 231         val  = in_be32(&mpc52xx_cdm->rstcfg);
 232         if (val & (1 << 5))
 233                 freq *= 8;
 234         else
 235                 freq *= 4;
 236         if (val & (1 << 6))
 237                 freq /= 12;
 238         else
 239                 freq /= 16;
 240
 241         return freq;
 242 }
 243 EXPORT_SYMBOL(mpc52xx_get_xtal_freq);
 244
 245 /**
 246  * mpc52xx_restart: ppc_md->restart hook for mpc5200 using the watchdog timer
 247  */
 248 void
 249 mpc52xx_restart(char *cmd)
 250 {
 251         local_irq_disable();
 252
 253         /* Turn on the watchdog and wait for it to expire.
 254          * It effectively does a reset. */
 255         if (mpc52xx_wdt) {
 256                 out_be32(&mpc52xx_wdt->mode, 0x00000000);
 257                 out_be32(&mpc52xx_wdt->count, 0x000000ff);
 258                 out_be32(&mpc52xx_wdt->mode, 0x00009004);
 259         } else
 260                 printk(KERN_ERR __FILE__ ": "
 261                         "mpc52xx_restart: Can't access wdt. "
 262                         "Restart impossible, system halted.\n");
 263
 264         while (1);
 265 }