target/linux/olpc/files-2.6.23/arch/i386/kernel/ofw.c

   1 /*
   2  * ofw.c - Open Firmware client interface for 32-bit systems.
   3  * This code is intended to be portable to any 32-bit Open Firmware
   4  * implementation with a standard client interface that can be
   5  * called when Linux is running.
   6  *
   7  * Copyright (C) 2007  Mitch Bradley <wmb@firmworks.com>
   8  * Copyright (C) 2007  Andres Salomon <dilinger@debian.org>
   9  */
  10
  11 #include <stdarg.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/module.h>
  14 #include <asm/ofw.h>
  15
  16
  17 int (*call_firmware)(int *);
  18
  19 static DEFINE_SPINLOCK(prom_lock);
  20
  21 #define MAXARGS 20
  22
  23 /*
  24  * The return value from ofw() in all cases is 0 if the attempt to call the
  25  * function succeeded, <0 otherwise.  That return value is from the
  26  * gateway function only.  Any results from the called function are returned
  27  * via output argument pointers.
  28  *
  29  * Here are call templates for all the standard OFW client services:
  30  *
  31  * ofw("test", 1, 1, namestr, &missing);
  32  * ofw("peer", 1, 1, phandle, &sibling_phandle);
  33  * ofw("child", 1, 1, phandle, &child_phandle);
  34  * ofw("parent", 1, 1, phandle, &parent_phandle);
  35  * ofw("instance_to_package", 1, 1, ihandle, &phandle);
  36  * ofw("getproplen", 2, 1, phandle, namestr, &proplen);
  37  * ofw("getprop", 4, 1, phandle, namestr, bufaddr, buflen, &size);
  38  * ofw("nextprop", 3, 1, phandle, previousstr, bufaddr, &flag);
  39  * ofw("setprop", 4, 1, phandle, namestr, bufaddr, len, &size);
  40  * ofw("canon", 3, 1, devspecstr, bufaddr, buflen, &length);
  41  * ofw("finddevice", 1, 1, devspecstr, &phandle);
  42  * ofw("instance-to-path", 3, 1, ihandle, bufaddr, buflen, &length);
  43  * ofw("package-to-path", 3, 1, phandle, bufaddr, buflen, &length);
  44  * ofw("call_method", numin, numout, in0, in1, ..., &out0, &out1, ...);
  45  * ofw("open", 1, 1, devspecstr, &ihandle);
  46  * ofw("close", 1, 0, ihandle);
  47  * ofw("read", 3, 1, ihandle, addr, len, &actual);
  48  * ofw("write", 3, 1, ihandle, addr, len, &actual);
  49  * ofw("seek", 3, 1, ihandle, pos_hi, pos_lo, &status);
  50  * ofw("claim", 3, 1, virtaddr, size, align, &baseaddr);
  51  * ofw("release", 2, 0, virtaddr, size);
  52  * ofw("boot", 1, 0, bootspecstr);
  53  * ofw("enter", 0, 0);
  54  * ofw("exit", 0, 0);
  55  * ofw("chain", 5, 0, virtaddr, size, entryaddr, argsaddr, len);
  56  * ofw("interpret", numin+1, numout+1, cmdstr, in0, ..., &catchres, &out0, ...);
  57  * ofw("set-callback", 1, 1, newfuncaddr, &oldfuncaddr);
  58  * ofw("set-symbol-lookup", 2, 0, symtovaladdr, valtosymaddr);
  59  * ofw("milliseconds", 0, 1, &ms);
  60  */
  61
  62 int ofw(char *name, int numargs, int numres, ...)
  63 {
  64         va_list ap;
  65         int argarray[MAXARGS+3];
  66         int argnum = 3;
  67         int retval;
  68         int *intp;
  69         unsigned long flags;
  70
  71         if (!call_firmware)
  72                 return -1;
  73         if ((numargs + numres) > MAXARGS)
  74                 return -1;      /* spit out an error? */
  75
  76         argarray[0] = (int) name;
  77         argarray[1] = numargs;
  78         argarray[2] = numres;
  79
  80         va_start(ap, numres);
  81         while (numargs) {
  82                 argarray[argnum++] = va_arg(ap, int);
  83                 numargs--;
  84         }
  85
  86         spin_lock_irqsave(&prom_lock, flags);
  87         retval = call_firmware(argarray);
  88         spin_unlock_irqrestore(&prom_lock, flags);
  89
  90         if (retval == 0) {
  91                 while (numres) {
  92                         intp = va_arg(ap, int *);
  93                         *intp = argarray[argnum++];
  94                         numres--;
  95                 }
  96         }
  97         va_end(ap);
  98         return retval;
  99 }
 100 EXPORT_SYMBOL(ofw);