linux/arch/powerpc/platforms/wsp/scom_wsp.c
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   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
  26static 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
  48static void wsp_scom_unmap(scom_map_t map)
  49{
  50        iounmap((void *)map);
  51}
  52
  53static 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
  60static 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
  67static 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
  74void scom_init_wsp(void)
  75{
  76        scom_init(&wsp_scom_controller);
  77}
  78