arch/mips/powertv/powertv_setup.c

   1 /*
   2  * Carsten Langgaard, carstenl@mips.com
   3  * Copyright (C) 2000 MIPS Technologies, Inc.  All rights reserved.
   4  * Portions copyright (C) 2009 Cisco Systems, Inc.
   5  *
   6  *  This program is free software; you can distribute it and/or modify it
   7  *  under the terms of the GNU General Public License (Version 2) as
   8  *  published by the Free Software Foundation.
   9  *
  10  *  This program is distributed in the hope it will be useful, but WITHOUT
  11  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  *  for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License along
  16  *  with this program; if not, write to the Free Software Foundation, Inc.,
  17  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  18  */
  19 #include <linux/init.h>
  20 #include <linux/sched.h>
  21 #include <linux/ioport.h>
  22 #include <linux/pci.h>
  23 #include <linux/screen_info.h>
  24 #include <linux/notifier.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/if_ether.h>
  27 #include <linux/ctype.h>
  28 #include <linux/cpu.h>
  29 #include <linux/time.h>
  30
  31 #include <asm/bootinfo.h>
  32 #include <asm/irq.h>
  33 #include <asm/mips-boards/generic.h>
  34 #include <asm/mips-boards/prom.h>
  35 #include <asm/dma.h>
  36 #include <asm/asm.h>
  37 #include <asm/traps.h>
  38 #include <asm/asm-offsets.h>
  39 #include "reset.h"
  40
  41 #define VAL(n)          STR(n)
  42
  43 /*
  44  * Macros for loading addresses and storing registers:
  45  * LONG_L_      Stringified version of LONG_L for use in asm() statement
  46  * LONG_S_      Stringified version of LONG_S for use in asm() statement
  47  * PTR_LA_      Stringified version of PTR_LA for use in asm() statement
  48  * REG_SIZE     Number of 8-bit bytes in a full width register
  49  */
  50 #define LONG_L_         VAL(LONG_L) " "
  51 #define LONG_S_         VAL(LONG_S) " "
  52 #define PTR_LA_         VAL(PTR_LA) " "
  53
  54 #ifdef CONFIG_64BIT
  55 #warning TODO: 64-bit code needs to be verified
  56 #define REG_SIZE        "8"             /* In bytes */
  57 #endif
  58
  59 #ifdef CONFIG_32BIT
  60 #define REG_SIZE        "4"             /* In bytes */
  61 #endif
  62
  63 static void register_panic_notifier(void);
  64 static int panic_handler(struct notifier_block *notifier_block,
  65         unsigned long event, void *cause_string);
  66
  67 const char *get_system_type(void)
  68 {
  69         return "PowerTV";
  70 }
  71
  72 void __init plat_mem_setup(void)
  73 {
  74         panic_on_oops = 1;
  75         register_panic_notifier();
  76
  77 #if 0
  78         mips_pcibios_init();
  79 #endif
  80         mips_reboot_setup();
  81 }
  82
  83 /*
  84  * Install a panic notifier for platform-specific diagnostics
  85  */
  86 static void register_panic_notifier()
  87 {
  88         static struct notifier_block panic_notifier = {
  89                 .notifier_call = panic_handler,
  90                 .next = NULL,
  91                 .priority       = INT_MAX
  92         };
  93         atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);
  94 }
  95
  96 static int panic_handler(struct notifier_block *notifier_block,
  97         unsigned long event, void *cause_string)
  98 {
  99         struct pt_regs  my_regs;
 100
 101         /* Save all of the registers */
 102         {
 103                 unsigned long   at, v0, v1; /* Must be on the stack */
 104
 105                 /* Start by saving $at and v0 on the stack. We use $at
 106                  * ourselves, but it looks like the compiler may use v0 or v1
 107                  * to load the address of the pt_regs structure. We'll come
 108                  * back later to store the registers in the pt_regs
 109                  * structure. */
 110                 __asm__ __volatile__ (
 111                         ".set   noat\n"
 112                         LONG_S_         "$at, %[at]\n"
 113                         LONG_S_         "$2, %[v0]\n"
 114                         LONG_S_         "$3, %[v1]\n"
 115                 :
 116                         [at] "=m" (at),
 117                         [v0] "=m" (v0),
 118                         [v1] "=m" (v1)
 119                 :
 120                 :       "at"
 121                 );
 122
 123                 __asm__ __volatile__ (
 124                         ".set   noat\n"
 125                         "move           $at, %[pt_regs]\n"
 126
 127                         /* Argument registers */
 128                         LONG_S_         "$4, " VAL(PT_R4) "($at)\n"
 129                         LONG_S_         "$5, " VAL(PT_R5) "($at)\n"
 130                         LONG_S_         "$6, " VAL(PT_R6) "($at)\n"
 131                         LONG_S_         "$7, " VAL(PT_R7) "($at)\n"
 132
 133                         /* Temporary regs */
 134                         LONG_S_         "$8, " VAL(PT_R8) "($at)\n"
 135                         LONG_S_         "$9, " VAL(PT_R9) "($at)\n"
 136                         LONG_S_         "$10, " VAL(PT_R10) "($at)\n"
 137                         LONG_S_         "$11, " VAL(PT_R11) "($at)\n"
 138                         LONG_S_         "$12, " VAL(PT_R12) "($at)\n"
 139                         LONG_S_         "$13, " VAL(PT_R13) "($at)\n"
 140                         LONG_S_         "$14, " VAL(PT_R14) "($at)\n"
 141                         LONG_S_         "$15, " VAL(PT_R15) "($at)\n"
 142
 143                         /* "Saved" registers */
 144                         LONG_S_         "$16, " VAL(PT_R16) "($at)\n"
 145                         LONG_S_         "$17, " VAL(PT_R17) "($at)\n"
 146                         LONG_S_         "$18, " VAL(PT_R18) "($at)\n"
 147                         LONG_S_         "$19, " VAL(PT_R19) "($at)\n"
 148                         LONG_S_         "$20, " VAL(PT_R20) "($at)\n"
 149                         LONG_S_         "$21, " VAL(PT_R21) "($at)\n"
 150                         LONG_S_         "$22, " VAL(PT_R22) "($at)\n"
 151                         LONG_S_         "$23, " VAL(PT_R23) "($at)\n"
 152
 153                         /* Add'l temp regs */
 154                         LONG_S_         "$24, " VAL(PT_R24) "($at)\n"
 155                         LONG_S_         "$25, " VAL(PT_R25) "($at)\n"
 156
 157                         /* Kernel temp regs */
 158                         LONG_S_         "$26, " VAL(PT_R26) "($at)\n"
 159                         LONG_S_         "$27, " VAL(PT_R27) "($at)\n"
 160
 161                         /* Global pointer, stack pointer, frame pointer and
 162                          * return address */
 163                         LONG_S_         "$gp, " VAL(PT_R28) "($at)\n"
 164                         LONG_S_         "$sp, " VAL(PT_R29) "($at)\n"
 165                         LONG_S_         "$fp, " VAL(PT_R30) "($at)\n"
 166                         LONG_S_         "$ra, " VAL(PT_R31) "($at)\n"
 167
 168                         /* Now we can get the $at and v0 registers back and
 169                          * store them */
 170                         LONG_L_         "$8, %[at]\n"
 171                         LONG_S_         "$8, " VAL(PT_R1) "($at)\n"
 172                         LONG_L_         "$8, %[v0]\n"
 173                         LONG_S_         "$8, " VAL(PT_R2) "($at)\n"
 174                         LONG_L_         "$8, %[v1]\n"
 175                         LONG_S_         "$8, " VAL(PT_R3) "($at)\n"
 176                 :
 177                 :
 178                         [at] "m" (at),
 179                         [v0] "m" (v0),
 180                         [v1] "m" (v1),
 181                         [pt_regs] "r" (&my_regs)
 182                 :       "at", "t0"
 183                 );
 184
 185                 /* Set the current EPC value to be the current location in this
 186                  * function */
 187                 __asm__ __volatile__ (
 188                         ".set   noat\n"
 189                 "1:\n"
 190                         PTR_LA_         "$at, 1b\n"
 191                         LONG_S_         "$at, %[cp0_epc]\n"
 192                 :
 193                         [cp0_epc] "=m" (my_regs.cp0_epc)
 194                 :
 195                 :       "at"
 196                 );
 197
 198                 my_regs.cp0_cause = read_c0_cause();
 199                 my_regs.cp0_status = read_c0_status();
 200         }
 201
 202         pr_crit("I'm feeling a bit sleepy. hmmmmm... perhaps a nap would... "
 203                 "zzzz... \n");
 204
 205         return NOTIFY_DONE;
 206 }
 207
 208 /* Information about the RF MAC address, if one was supplied on the
 209  * command line. */
 210 static bool have_rfmac;
 211 static u8 rfmac[ETH_ALEN];
 212
 213 static int rfmac_param(char *p)
 214 {
 215         u8      *q;
 216         bool    is_high_nibble;
 217         int     c;
 218
 219         /* Skip a leading "0x", if present */
 220         if (*p == '0' && *(p+1) == 'x')
 221                 p += 2;
 222
 223         q = rfmac;
 224         is_high_nibble = true;
 225
 226         for (c = (unsigned char) *p++;
 227                 isxdigit(c) && q - rfmac < ETH_ALEN;
 228                 c = (unsigned char) *p++) {
 229                 int     nibble;
 230
 231                 nibble = (isdigit(c) ? (c - '0') :
 232                         (isupper(c) ? c - 'A' + 10 : c - 'a' + 10));
 233
 234                 if (is_high_nibble)
 235                         *q = nibble << 4;
 236                 else
 237                         *q++ |= nibble;
 238
 239                 is_high_nibble = !is_high_nibble;
 240         }
 241
 242         /* If we parsed all the way to the end of the parameter value and
 243          * parsed all ETH_ALEN bytes, we have a usable RF MAC address */
 244         have_rfmac = (c == '\0' && q - rfmac == ETH_ALEN);
 245
 246         return 0;
 247 }
 248
 249 early_param("rfmac", rfmac_param);
 250
 251 /*
 252  * Generate an Ethernet MAC address that has a good chance of being unique.
 253  * @addr:       Pointer to six-byte array containing the Ethernet address
 254  * Generates an Ethernet MAC address that is highly likely to be unique for
 255  * this particular system on a network with other systems of the same type.
 256  *
 257  * The problem we are solving is that, when random_ether_addr() is used to
 258  * generate MAC addresses at startup, there isn't much entropy for the random
 259  * number generator to use and the addresses it produces are fairly likely to
 260  * be the same as those of other identical systems on the same local network.
 261  * This is true even for relatively small numbers of systems (for the reason
 262  * why, see the Wikipedia entry for "Birthday problem" at:
 263  *      http://en.wikipedia.org/wiki/Birthday_problem
 264  *
 265  * The good news is that we already have a MAC address known to be unique, the
 266  * RF MAC address. The bad news is that this address is already in use on the
 267  * RF interface. Worse, the obvious trick, taking the RF MAC address and
 268  * turning on the locally managed bit, has already been used for other devices.
 269  * Still, this does give us something to work with.
 270  *
 271  * The approach we take is:
 272  * 1.   If we can't get the RF MAC Address, just call random_ether_addr.
 273  * 2.   Use the 24-bit NIC-specific bits of the RF MAC address as the last 24
 274  *      bits of the new address. This is very likely to be unique, except for
 275  *      the current box.
 276  * 3.   To avoid using addresses already on the current box, we set the top
 277  *      six bits of the address with a value different from any currently
 278  *      registered Scientific Atlanta organizationally unique identifyer
 279  *      (OUI). This avoids duplication with any addresses on the system that
 280  *      were generated from valid Scientific Atlanta-registered address by
 281  *      simply flipping the locally managed bit.
 282  * 4.   We aren't generating a multicast address, so we leave the multicast
 283  *      bit off. Since we aren't using a registered address, we have to set
 284  *      the locally managed bit.
 285  * 5.   We then randomly generate the remaining 16-bits. This does two
 286  *      things:
 287  *      a.      It allows us to call this function for more than one device
 288  *              in this system
 289  *      b.      It ensures that things will probably still work even if
 290  *              some device on the device network has a locally managed
 291  *              address that matches the top six bits from step 2.
 292  */
 293 void platform_random_ether_addr(u8 addr[ETH_ALEN])
 294 {
 295         const int num_random_bytes = 2;
 296         const unsigned char non_sciatl_oui_bits = 0xc0u;
 297         const unsigned char mac_addr_locally_managed = (1 << 1);
 298
 299         if (!have_rfmac) {
 300                 pr_warning("rfmac not available on command line; "
 301                         "generating random MAC address\n");
 302                 random_ether_addr(addr);
 303         }
 304
 305         else {
 306                 int     i;
 307
 308                 /* Set the first byte to something that won't match a Scientific
 309                  * Atlanta OUI, is locally managed, and isn't a multicast
 310                  * address */
 311                 addr[0] = non_sciatl_oui_bits | mac_addr_locally_managed;
 312
 313                 /* Get some bytes of random address information */
 314                 get_random_bytes(&addr[1], num_random_bytes);
 315
 316                 /* Copy over the NIC-specific bits of the RF MAC address */
 317                 for (i = 1 + num_random_bytes; i < ETH_ALEN; i++)
 318                         addr[i] = rfmac[i];
 319         }
 320 }