arch/powerpc/platforms/wsp/scom_wsp.c

   1 /*
   2  *  SCOM backend for WSP
   3  *
   4  *  Copyright 2010 Benjamin Herrenschmidt, IBM Corp.
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License
   8  *  as published by the Free Software Foundation; either version
   9  *  2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/cpumask.h>
  13 #include <linux/io.h>
  14 #include <linux/of.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/types.h>
  17
  18 #include <asm/cputhreads.h>
  19 #include <asm/reg_a2.h>
  20 #include <asm/scom.h>
  21 #include <asm/udbg.h>
  22
  23 #include "wsp.h"
  24
  25
  26 static scom_map_t wsp_scom_map(struct device_node *dev, u64 reg, u64 count)
  27 {
  28         struct resource r;
  29         u64 xscom_addr;
  30
  31         if (!of_get_property(dev, "scom-controller", NULL)) {
  32                 pr_err("%s: device %s is not a SCOM controller\n",
  33                         __func__, dev->full_name);
  34                 return SCOM_MAP_INVALID;
  35         }
  36
  37         if (of_address_to_resource(dev, 0, &r)) {
  38                 pr_debug("Failed to find SCOM controller address\n");
  39                 return 0;
  40         }
  41
  42         /* Transform the SCOM address into an XSCOM offset */
  43         xscom_addr = ((reg & 0x7f000000) >> 1) | ((reg & 0xfffff) << 3);
  44
  45         return (scom_map_t)ioremap(r.start + xscom_addr, count << 3);
  46 }
  47
  48 static void wsp_scom_unmap(scom_map_t map)
  49 {
  50         iounmap((void *)map);
  51 }
  52
  53 static u64 wsp_scom_read(scom_map_t map, u32 reg)
  54 {
  55         u64 __iomem *addr = (u64 __iomem *)map;
  56
  57         return in_be64(addr + reg);
  58 }
  59
  60 static void wsp_scom_write(scom_map_t map, u32 reg, u64 value)
  61 {
  62         u64 __iomem *addr = (u64 __iomem *)map;
  63
  64         return out_be64(addr + reg, value);
  65 }
  66
  67 static const struct scom_controller wsp_scom_controller = {
  68         .map    = wsp_scom_map,
  69         .unmap  = wsp_scom_unmap,
  70         .read   = wsp_scom_read,
  71         .write  = wsp_scom_write
  72 };
  73
  74 void scom_init_wsp(void)
  75 {
  76         scom_init(&wsp_scom_controller);
  77 }