arch/ia64/kernel/fw-emu.c

   1 /*
   2  * PAL & SAL emulation.
   3  *
   4  * Copyright (C) 1998-2001 Hewlett-Packard Co
   5  *      David Mosberger-Tang <davidm@hpl.hp.com>
   6  *
   7  * For the HP simulator, this file gets include in boot/bootloader.c.
   8  * For SoftSDV, this file gets included in sys_softsdv.c.
   9  */
  10 #include <linux/config.h>
  11
  12 #ifdef CONFIG_PCI
  13 # include <linux/pci.h>
  14 #endif
  15
  16 #include <linux/efi.h>
  17 #include <asm/io.h>
  18 #include <asm/pal.h>
  19 #include <asm/sal.h>
  20
  21 #define MB      (1024*1024UL)
  22
  23 #define SIMPLE_MEMMAP   1
  24
  25 #if SIMPLE_MEMMAP
  26 # define NUM_MEM_DESCS  4
  27 #else
  28 # define NUM_MEM_DESCS  16
  29 #endif
  30
  31 static char fw_mem[(  sizeof(struct ia64_boot_param)
  32                     + sizeof(efi_system_table_t)
  33                     + sizeof(efi_runtime_services_t)
  34                     + 1*sizeof(efi_config_table_t)
  35                     + sizeof(struct ia64_sal_systab)
  36                     + sizeof(struct ia64_sal_desc_entry_point)
  37                     + NUM_MEM_DESCS*(sizeof(efi_memory_desc_t))
  38                     + 1024)] __attribute__ ((aligned (8)));
  39
  40 #ifdef CONFIG_IA64_HP_SIM
  41
  42 /* Simulator system calls: */
  43
  44 #define SSC_EXIT        66
  45
  46 /*
  47  * Simulator system call.
  48  */
  49 static long
  50 ssc (long arg0, long arg1, long arg2, long arg3, int nr)
  51 {
  52         register long r8 asm ("r8");
  53
  54         asm volatile ("mov r15=%1\n\t"
  55                       "break 0x80001"
  56                       : "=r"(r8)
  57                       : "r"(nr), "r"(arg0), "r"(arg1), "r"(arg2), "r"(arg3));
  58         return r8;
  59 }
  60
  61 #define SECS_PER_HOUR   (60 * 60)
  62 #define SECS_PER_DAY    (SECS_PER_HOUR * 24)
  63
  64 /* Compute the `struct tm' representation of *T,
  65    offset OFFSET seconds east of UTC,
  66    and store year, yday, mon, mday, wday, hour, min, sec into *TP.
  67    Return nonzero if successful.  */
  68 int
  69 offtime (unsigned long t, efi_time_t *tp)
  70 {
  71         const unsigned short int __mon_yday[2][13] =
  72         {
  73                 /* Normal years.  */
  74                 { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
  75                 /* Leap years.  */
  76                 { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
  77         };
  78         long int days, rem, y;
  79         const unsigned short int *ip;
  80
  81         days = t / SECS_PER_DAY;
  82         rem = t % SECS_PER_DAY;
  83         while (rem < 0) {
  84                 rem += SECS_PER_DAY;
  85                 --days;
  86         }
  87         while (rem >= SECS_PER_DAY) {
  88                 rem -= SECS_PER_DAY;
  89                 ++days;
  90         }
  91         tp->hour = rem / SECS_PER_HOUR;
  92         rem %= SECS_PER_HOUR;
  93         tp->minute = rem / 60;
  94         tp->second = rem % 60;
  95         /* January 1, 1970 was a Thursday.  */
  96         y = 1970;
  97
  98 #       define DIV(a, b) ((a) / (b) - ((a) % (b) < 0))
  99 #       define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400))
 100 #       define __isleap(year) \
 101           ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 102
 103         while (days < 0 || days >= (__isleap (y) ? 366 : 365)) {
 104                 /* Guess a corrected year, assuming 365 days per year.  */
 105                 long int yg = y + days / 365 - (days % 365 < 0);
 106
 107                 /* Adjust DAYS and Y to match the guessed year.  */
 108                 days -= ((yg - y) * 365 + LEAPS_THRU_END_OF (yg - 1)
 109                          - LEAPS_THRU_END_OF (y - 1));
 110                 y = yg;
 111         }
 112         tp->year = y;
 113         ip = __mon_yday[__isleap(y)];
 114         for (y = 11; days < (long int) ip[y]; --y)
 115                 continue;
 116         days -= ip[y];
 117         tp->month = y + 1;
 118         tp->day = days + 1;
 119         return 1;
 120 }
 121
 122 #endif /* CONFIG_IA64_HP_SIM */
 123
 124 /*
 125  * Very ugly, but we need this in the simulator only.  Once we run on
 126  * real hw, this can all go away.
 127  */
 128 extern void pal_emulator_static (void);
 129
 130 asm (
 131 "       .proc pal_emulator_static\n"
 132 "pal_emulator_static:"
 133 "       mov r8=-1\n"
 134 "       mov r9=256\n"
 135 "       ;;\n"
 136 "       cmp.gtu p6,p7=r9,r28            /* r28 <= 255? */\n"
 137 "(p6)   br.cond.sptk.few static\n"
 138 "       ;;\n"
 139 "       mov r9=512\n"
 140 "       ;;\n"
 141 "       cmp.gtu p6,p7=r9,r28\n"
 142 "(p6)   br.cond.sptk.few stacked\n"
 143 "       ;;\n"
 144 "static:        cmp.eq p6,p7=6,r28              /* PAL_PTCE_INFO */\n"
 145 "(p7)   br.cond.sptk.few 1f\n"
 146 "       ;;\n"
 147 "       mov r8=0                        /* status = 0 */\n"
 148 "       movl r9=0x100000000             /* tc.base */\n"
 149 "       movl r10=0x0000000200000003     /* count[0], count[1] */\n"
 150 "       movl r11=0x1000000000002000     /* stride[0], stride[1] */\n"
 151 "       br.cond.sptk.few rp\n"
 152 "1:     cmp.eq p6,p7=14,r28             /* PAL_FREQ_RATIOS */\n"
 153 "(p7)   br.cond.sptk.few 1f\n"
 154 "       mov r8=0                        /* status = 0 */\n"
 155 "       movl r9 =0x100000064            /* proc_ratio (1/100) */\n"
 156 "       movl r10=0x100000100            /* bus_ratio<<32 (1/256) */\n"
 157 "       movl r11=0x100000064            /* itc_ratio<<32 (1/100) */\n"
 158 "       ;;\n"
 159 "1:     cmp.eq p6,p7=19,r28             /* PAL_RSE_INFO */\n"
 160 "(p7)   br.cond.sptk.few 1f\n"
 161 "       mov r8=0                        /* status = 0 */\n"
 162 "       mov r9=96                       /* num phys stacked */\n"
 163 "       mov r10=0                       /* hints */\n"
 164 "       mov r11=0\n"
 165 "       br.cond.sptk.few rp\n"
 166 "1:     cmp.eq p6,p7=1,r28              /* PAL_CACHE_FLUSH */\n"
 167 "(p7)   br.cond.sptk.few 1f\n"
 168 "       mov r9=ar.lc\n"
 169 "       movl r8=524288                  /* flush 512k million cache lines (16MB) */\n"
 170 "       ;;\n"
 171 "       mov ar.lc=r8\n"
 172 "       movl r8=0xe000000000000000\n"
 173 "       ;;\n"
 174 ".loop: fc r8\n"
 175 "       add r8=32,r8\n"
 176 "       br.cloop.sptk.few .loop\n"
 177 "       sync.i\n"
 178 "       ;;\n"
 179 "       srlz.i\n"
 180 "       ;;\n"
 181 "       mov ar.lc=r9\n"
 182 "       mov r8=r0\n"
 183 "       ;;\n"
 184 "1:     cmp.eq p6,p7=15,r28             /* PAL_PERF_MON_INFO */\n"
 185 "(p7)   br.cond.sptk.few 1f\n"
 186 "       mov r8=0                        /* status = 0 */\n"
 187 "       movl r9 =0x12082004             /* generic=4 width=32 retired=8 cycles=18 */\n"
 188 "       mov r10=0                       /* reserved */\n"
 189 "       mov r11=0                       /* reserved */\n"
 190 "       mov r16=0xffff                  /* implemented PMC */\n"
 191 "       mov r17=0xffff                  /* implemented PMD */\n"
 192 "       add r18=8,r29                   /* second index */\n"
 193 "       ;;\n"
 194 "       st8 [r29]=r16,16                /* store implemented PMC */\n"
 195 "       st8 [r18]=r0,16                 /* clear remaining bits  */\n"
 196 "       ;;\n"
 197 "       st8 [r29]=r0,16                 /* store implemented PMC */\n"
 198 "       st8 [r18]=r0,16                 /* clear remaining bits  */\n"
 199 "       ;;\n"
 200 "       st8 [r29]=r17,16                /* store implemented PMD */\n"
 201 "       st8 [r18]=r0,16                 /* clear remaining bits  */\n"
 202 "       mov r16=0xf0                    /* cycles count capable PMC */\n"
 203 "       ;;\n"
 204 "       st8 [r29]=r0,16                 /* store implemented PMC */\n"
 205 "       st8 [r18]=r0,16                 /* clear remaining bits  */\n"
 206 "       mov r17=0x10                    /* retired bundles capable PMC */\n"
 207 "       ;;\n"
 208 "       st8 [r29]=r16,16                /* store cycles capable */\n"
 209 "       st8 [r18]=r0,16                 /* clear remaining bits  */\n"
 210 "       ;;\n"
 211 "       st8 [r29]=r0,16                 /* store implemented PMC */\n"
 212 "       st8 [r18]=r0,16                 /* clear remaining bits  */\n"
 213 "       ;;\n"
 214 "       st8 [r29]=r17,16                /* store retired bundle capable */\n"
 215 "       st8 [r18]=r0,16                 /* clear remaining bits  */\n"
 216 "       ;;\n"
 217 "       st8 [r29]=r0,16                 /* store implemented PMC */\n"
 218 "       st8 [r18]=r0,16                 /* clear remaining bits  */\n"
 219 "       ;;\n"
 220 "1:     br.cond.sptk.few rp\n"
 221 "stacked:\n"
 222 "       br.ret.sptk.few rp\n"
 223 "       .endp pal_emulator_static\n");
 224
 225 /* Macro to emulate SAL call using legacy IN and OUT calls to CF8, CFC etc.. */
 226
 227 #define BUILD_CMD(addr)         ((0x80000000 | (addr)) & ~3)
 228
 229 #define REG_OFFSET(addr)        (0x00000000000000FF & (addr))
 230 #define DEVICE_FUNCTION(addr)   (0x000000000000FF00 & (addr))
 231 #define BUS_NUMBER(addr)        (0x0000000000FF0000 & (addr))
 232
 233 static efi_status_t
 234 efi_get_time (efi_time_t *tm, efi_time_cap_t *tc)
 235 {
 236 #ifdef CONFIG_IA64_HP_SIM
 237         struct {
 238                 int tv_sec;     /* must be 32bits to work */
 239                 int tv_usec;
 240         } tv32bits;
 241
 242         ssc((unsigned long) &tv32bits, 0, 0, 0, SSC_GET_TOD);
 243
 244         memset(tm, 0, sizeof(*tm));
 245         offtime(tv32bits.tv_sec, tm);
 246
 247         if (tc)
 248                 memset(tc, 0, sizeof(*tc));
 249 #else
 250 #       error Not implemented yet...
 251 #endif
 252         return EFI_SUCCESS;
 253 }
 254
 255 static void
 256 efi_reset_system (int reset_type, efi_status_t status, unsigned long data_size, efi_char16_t *data)
 257 {
 258 #ifdef CONFIG_IA64_HP_SIM
 259         ssc(status, 0, 0, 0, SSC_EXIT);
 260 #else
 261 #       error Not implemented yet...
 262 #endif
 263 }
 264
 265 static efi_status_t
 266 efi_unimplemented (void)
 267 {
 268         return EFI_UNSUPPORTED;
 269 }
 270
 271 static long
 272 sal_emulator (long index, unsigned long in1, unsigned long in2,
 273               unsigned long in3, unsigned long in4, unsigned long in5,
 274               unsigned long in6, unsigned long in7)
 275 {
 276         register long r9 asm ("r9") = 0;
 277         register long r10 asm ("r10") = 0;
 278         register long r11 asm ("r11") = 0;
 279         long status;
 280
 281         /*
 282          * Don't do a "switch" here since that gives us code that
 283          * isn't self-relocatable.
 284          */
 285         status = 0;
 286         if (index == SAL_FREQ_BASE) {
 287                 switch (in1) {
 288                       case SAL_FREQ_BASE_PLATFORM:
 289                         r9 = 200000000;
 290                         break;
 291
 292                       case SAL_FREQ_BASE_INTERVAL_TIMER:
 293                         /*
 294                          * Is this supposed to be the cr.itc frequency
 295                          * or something platform specific?  The SAL
 296                          * doc ain't exactly clear on this...
 297                          */
 298                         r9 = 700000000;
 299                         break;
 300
 301                       case SAL_FREQ_BASE_REALTIME_CLOCK:
 302                         r9 = 1;
 303                         break;
 304
 305                       default:
 306                         status = -1;
 307                         break;
 308                 }
 309         } else if (index == SAL_SET_VECTORS) {
 310                 ;
 311         } else if (index == SAL_GET_STATE_INFO) {
 312                 ;
 313         } else if (index == SAL_GET_STATE_INFO_SIZE) {
 314                 ;
 315         } else if (index == SAL_CLEAR_STATE_INFO) {
 316                 ;
 317         } else if (index == SAL_MC_RENDEZ) {
 318                 ;
 319         } else if (index == SAL_MC_SET_PARAMS) {
 320                 ;
 321         } else if (index == SAL_CACHE_FLUSH) {
 322                 ;
 323         } else if (index == SAL_CACHE_INIT) {
 324                 ;
 325 #ifdef CONFIG_PCI
 326         } else if (index == SAL_PCI_CONFIG_READ) {
 327                 /*
 328                  * in1 contains the PCI configuration address and in2
 329                  * the size of the read.  The value that is read is
 330                  * returned via the general register r9.
 331                  */
 332                 outl(BUILD_CMD(in1), 0xCF8);
 333                 if (in2 == 1)                           /* Reading byte  */
 334                         r9 = inb(0xCFC + ((REG_OFFSET(in1) & 3)));
 335                 else if (in2 == 2)                      /* Reading word  */
 336                         r9 = inw(0xCFC + ((REG_OFFSET(in1) & 2)));
 337                 else                                    /* Reading dword */
 338                         r9 = inl(0xCFC);
 339                 status = PCIBIOS_SUCCESSFUL;
 340         } else if (index == SAL_PCI_CONFIG_WRITE) {
 341                 /*
 342                  * in1 contains the PCI configuration address, in2 the
 343                  * size of the write, and in3 the actual value to be
 344                  * written out.
 345                  */
 346                 outl(BUILD_CMD(in1), 0xCF8);
 347                 if (in2 == 1)                           /* Writing byte  */
 348                         outb(in3, 0xCFC + ((REG_OFFSET(in1) & 3)));
 349                 else if (in2 == 2)                      /* Writing word  */
 350                         outw(in3, 0xCFC + ((REG_OFFSET(in1) & 2)));
 351                 else                                    /* Writing dword */
 352                         outl(in3, 0xCFC);
 353                 status = PCIBIOS_SUCCESSFUL;
 354 #endif /* CONFIG_PCI */
 355         } else if (index == SAL_UPDATE_PAL) {
 356                 ;
 357         } else {
 358                 status = -1;
 359         }
 360         asm volatile ("" :: "r"(r9), "r"(r10), "r"(r11));
 361         return status;
 362 }
 363
 364
 365 /*
 366  * This is here to work around a bug in egcs-1.1.1b that causes the
 367  * compiler to crash (seems like a bug in the new alias analysis code.
 368  */
 369 void *
 370 id (long addr)
 371 {
 372         return (void *) addr;
 373 }
 374
 375 struct ia64_boot_param *
 376 sys_fw_init (const char *args, int arglen)
 377 {
 378         efi_system_table_t *efi_systab;
 379         efi_runtime_services_t *efi_runtime;
 380         efi_config_table_t *efi_tables;
 381         struct ia64_sal_systab *sal_systab;
 382         efi_memory_desc_t *efi_memmap, *md;
 383         unsigned long *pal_desc, *sal_desc;
 384         struct ia64_sal_desc_entry_point *sal_ed;
 385         struct ia64_boot_param *bp;
 386         unsigned char checksum = 0;
 387         char *cp, *cmd_line;
 388         int i = 0;
 389 #       define MAKE_MD(typ, attr, start, end)           \
 390         do {                                            \
 391                 md = efi_memmap + i++;                  \
 392                 md->type = typ;                         \
 393                 md->pad = 0;                            \
 394                 md->phys_addr = start;                  \
 395                 md->virt_addr = 0;                      \
 396                 md->num_pages = (end - start) >> 12;    \
 397                 md->attribute = attr;                   \
 398         } while (0)
 399
 400         memset(fw_mem, 0, sizeof(fw_mem));
 401
 402         pal_desc = (unsigned long *) &pal_emulator_static;
 403         sal_desc = (unsigned long *) &sal_emulator;
 404
 405         cp = fw_mem;
 406         efi_systab  = (void *) cp; cp += sizeof(*efi_systab);
 407         efi_runtime = (void *) cp; cp += sizeof(*efi_runtime);
 408         efi_tables  = (void *) cp; cp += sizeof(*efi_tables);
 409         sal_systab  = (void *) cp; cp += sizeof(*sal_systab);
 410         sal_ed      = (void *) cp; cp += sizeof(*sal_ed);
 411         efi_memmap  = (void *) cp; cp += NUM_MEM_DESCS*sizeof(*efi_memmap);
 412         bp          = (void *) cp; cp += sizeof(*bp);
 413         cmd_line    = (void *) cp;
 414
 415         if (args) {
 416                 if (arglen >= 1024)
 417                         arglen = 1023;
 418                 memcpy(cmd_line, args, arglen);
 419         } else {
 420                 arglen = 0;
 421         }
 422         cmd_line[arglen] = '\0';
 423
 424         memset(efi_systab, 0, sizeof(efi_systab));
 425         efi_systab->hdr.signature = EFI_SYSTEM_TABLE_SIGNATURE;
 426         efi_systab->hdr.revision  = EFI_SYSTEM_TABLE_REVISION;
 427         efi_systab->hdr.headersize = sizeof(efi_systab->hdr);
 428         efi_systab->fw_vendor = __pa("H\0e\0w\0l\0e\0t\0t\0-\0P\0a\0c\0k\0a\0r\0d\0\0");
 429         efi_systab->fw_revision = 1;
 430         efi_systab->runtime = __pa(efi_runtime);
 431         efi_systab->nr_tables = 1;
 432         efi_systab->tables = __pa(efi_tables);
 433
 434         efi_runtime->hdr.signature = EFI_RUNTIME_SERVICES_SIGNATURE;
 435         efi_runtime->hdr.revision = EFI_RUNTIME_SERVICES_REVISION;
 436         efi_runtime->hdr.headersize = sizeof(efi_runtime->hdr);
 437         efi_runtime->get_time = __pa(&efi_get_time);
 438         efi_runtime->set_time = __pa(&efi_unimplemented);
 439         efi_runtime->get_wakeup_time = __pa(&efi_unimplemented);
 440         efi_runtime->set_wakeup_time = __pa(&efi_unimplemented);
 441         efi_runtime->set_virtual_address_map = __pa(&efi_unimplemented);
 442         efi_runtime->get_variable = __pa(&efi_unimplemented);
 443         efi_runtime->get_next_variable = __pa(&efi_unimplemented);
 444         efi_runtime->set_variable = __pa(&efi_unimplemented);
 445         efi_runtime->get_next_high_mono_count = __pa(&efi_unimplemented);
 446         efi_runtime->reset_system = __pa(&efi_reset_system);
 447
 448         efi_tables->guid = SAL_SYSTEM_TABLE_GUID;
 449         efi_tables->table = __pa(sal_systab);
 450
 451         /* fill in the SAL system table: */
 452         memcpy(sal_systab->signature, "SST_", 4);
 453         sal_systab->size = sizeof(*sal_systab);
 454         sal_systab->sal_rev_minor = 1;
 455         sal_systab->sal_rev_major = 0;
 456         sal_systab->entry_count = 1;
 457
 458 #ifdef CONFIG_IA64_GENERIC
 459         strcpy(sal_systab->oem_id, "Generic");
 460         strcpy(sal_systab->product_id, "IA-64 system");
 461 #endif
 462
 463 #ifdef CONFIG_IA64_HP_SIM
 464         strcpy(sal_systab->oem_id, "Hewlett-Packard");
 465         strcpy(sal_systab->product_id, "HP-simulator");
 466 #endif
 467
 468 #ifdef CONFIG_IA64_SDV
 469         strcpy(sal_systab->oem_id, "Intel");
 470         strcpy(sal_systab->product_id, "SDV");
 471 #endif
 472
 473         /* fill in an entry point: */
 474         sal_ed->type = SAL_DESC_ENTRY_POINT;
 475         sal_ed->pal_proc = __pa(pal_desc[0]);
 476         sal_ed->sal_proc = __pa(sal_desc[0]);
 477         sal_ed->gp = __pa(sal_desc[1]);
 478
 479         for (cp = (char *) sal_systab; cp < (char *) efi_memmap; ++cp)
 480                 checksum += *cp;
 481
 482         sal_systab->checksum = -checksum;
 483
 484 #if SIMPLE_MEMMAP
 485         /* simulate free memory at physical address zero */
 486         MAKE_MD(EFI_BOOT_SERVICES_DATA,         EFI_MEMORY_WB,    0*MB,    1*MB);
 487         MAKE_MD(EFI_PAL_CODE,                   EFI_MEMORY_WB,    1*MB,    2*MB);
 488         MAKE_MD(EFI_CONVENTIONAL_MEMORY,        EFI_MEMORY_WB,    2*MB,  130*MB);
 489         MAKE_MD(EFI_CONVENTIONAL_MEMORY,        EFI_MEMORY_WB, 4096*MB, 4128*MB);
 490 #else
 491         MAKE_MD( 4,                0x9, 0x0000000000000000, 0x0000000000001000);
 492         MAKE_MD( 7,                0x9, 0x0000000000001000, 0x000000000008a000);
 493         MAKE_MD( 4,                0x9, 0x000000000008a000, 0x00000000000a0000);
 494         MAKE_MD( 5, 0x8000000000000009, 0x00000000000c0000, 0x0000000000100000);
 495         MAKE_MD( 7,                0x9, 0x0000000000100000, 0x0000000004400000);
 496         MAKE_MD( 2,                0x9, 0x0000000004400000, 0x0000000004be5000);
 497         MAKE_MD( 7,                0x9, 0x0000000004be5000, 0x000000007f77e000);
 498         MAKE_MD( 6, 0x8000000000000009, 0x000000007f77e000, 0x000000007fb94000);
 499         MAKE_MD( 6, 0x8000000000000009, 0x000000007fb94000, 0x000000007fb95000);
 500         MAKE_MD( 6, 0x8000000000000009, 0x000000007fb95000, 0x000000007fc00000);
 501         MAKE_MD(13, 0x8000000000000009, 0x000000007fc00000, 0x000000007fc3a000);
 502         MAKE_MD( 7,                0x9, 0x000000007fc3a000, 0x000000007fea0000);
 503         MAKE_MD( 5, 0x8000000000000009, 0x000000007fea0000, 0x000000007fea8000);
 504         MAKE_MD( 7,                0x9, 0x000000007fea8000, 0x000000007feab000);
 505         MAKE_MD( 5, 0x8000000000000009, 0x000000007feab000, 0x000000007ffff000);
 506         MAKE_MD( 7,                0x9, 0x00000000ff400000, 0x0000000104000000);
 507 #endif
 508
 509         bp->efi_systab = __pa(&fw_mem);
 510         bp->efi_memmap = __pa(efi_memmap);
 511         bp->efi_memmap_size = NUM_MEM_DESCS*sizeof(efi_memory_desc_t);
 512         bp->efi_memdesc_size = sizeof(efi_memory_desc_t);
 513         bp->efi_memdesc_version = 1;
 514         bp->command_line = __pa(cmd_line);
 515         bp->console_info.num_cols = 80;
 516         bp->console_info.num_rows = 25;
 517         bp->console_info.orig_x = 0;
 518         bp->console_info.orig_y = 24;
 519         bp->fpswa = 0;
 520
 521         return bp;
 522 }