1/*
   2 * OpenRISC head.S
   3 *
   4 * Linux architectural port borrowing liberally from similar works of
   5 * others.  All original copyrights apply as per the original source
   6 * declaration.
   7 *
   8 * Modifications for the OpenRISC architecture:
   9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  11 *
  12 *      This program is free software; you can redistribute it and/or
  13 *      modify it under the terms of the GNU General Public License
  14 *      as published by the Free Software Foundation; either version
  15 *      2 of the License, or (at your option) any later version.
  16 */
  17
  18#include <linux/linkage.h>
  19#include <linux/threads.h>
  20#include <linux/errno.h>
  21#include <linux/init.h>
  22#include <linux/serial_reg.h>
 
  23#include <asm/processor.h>
  24#include <asm/page.h>
  25#include <asm/mmu.h>
  26#include <asm/pgtable.h>
  27#include <asm/thread_info.h>
  28#include <asm/cache.h>
  29#include <asm/spr_defs.h>
  30#include <asm/asm-offsets.h>
  31#include <linux/of_fdt.h>
  32
  33#define tophys(rd,rs)				\
  34	l.movhi	rd,hi(-KERNELBASE)		;\
  35	l.add	rd,rd,rs
  36
  37#define CLEAR_GPR(gpr)				\
  38	l.movhi	gpr,0x0
  39
  40#define LOAD_SYMBOL_2_GPR(gpr,symbol)		\
  41	l.movhi gpr,hi(symbol)			;\
  42	l.ori   gpr,gpr,lo(symbol)
  43
  44
  45#define UART_BASE_ADD      0x90000000
  46
  47#define EXCEPTION_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_SM)
  48#define SYSCALL_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_IEE | SPR_SR_TEE | SPR_SR_SM)
  49
  50/* ============================================[ tmp store locations ]=== */
  51
  52#define SPR_SHADOW_GPR(x)	((x) + SPR_GPR_BASE + 32)
  53
  54/*
  55 * emergency_print temporary stores
  56 */
  57#ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
  58#define EMERGENCY_PRINT_STORE_GPR4	l.mtspr r0,r4,SPR_SHADOW_GPR(14)
  59#define EMERGENCY_PRINT_LOAD_GPR4	l.mfspr r4,r0,SPR_SHADOW_GPR(14)
  60
  61#define EMERGENCY_PRINT_STORE_GPR5	l.mtspr r0,r5,SPR_SHADOW_GPR(15)
  62#define EMERGENCY_PRINT_LOAD_GPR5	l.mfspr r5,r0,SPR_SHADOW_GPR(15)
  63
  64#define EMERGENCY_PRINT_STORE_GPR6	l.mtspr r0,r6,SPR_SHADOW_GPR(16)
  65#define EMERGENCY_PRINT_LOAD_GPR6	l.mfspr r6,r0,SPR_SHADOW_GPR(16)
  66
  67#define EMERGENCY_PRINT_STORE_GPR7	l.mtspr r0,r7,SPR_SHADOW_GPR(7)
  68#define EMERGENCY_PRINT_LOAD_GPR7	l.mfspr r7,r0,SPR_SHADOW_GPR(7)
  69
  70#define EMERGENCY_PRINT_STORE_GPR8	l.mtspr r0,r8,SPR_SHADOW_GPR(8)
  71#define EMERGENCY_PRINT_LOAD_GPR8	l.mfspr r8,r0,SPR_SHADOW_GPR(8)
  72
  73#define EMERGENCY_PRINT_STORE_GPR9	l.mtspr r0,r9,SPR_SHADOW_GPR(9)
  74#define EMERGENCY_PRINT_LOAD_GPR9	l.mfspr r9,r0,SPR_SHADOW_GPR(9)
  75
  76#else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
  77#define EMERGENCY_PRINT_STORE_GPR4	l.sw    0x20(r0),r4
  78#define EMERGENCY_PRINT_LOAD_GPR4	l.lwz   r4,0x20(r0)
  79
  80#define EMERGENCY_PRINT_STORE_GPR5	l.sw    0x24(r0),r5
  81#define EMERGENCY_PRINT_LOAD_GPR5	l.lwz   r5,0x24(r0)
  82
  83#define EMERGENCY_PRINT_STORE_GPR6	l.sw    0x28(r0),r6
  84#define EMERGENCY_PRINT_LOAD_GPR6	l.lwz   r6,0x28(r0)
  85
  86#define EMERGENCY_PRINT_STORE_GPR7	l.sw    0x2c(r0),r7
  87#define EMERGENCY_PRINT_LOAD_GPR7	l.lwz   r7,0x2c(r0)
  88
  89#define EMERGENCY_PRINT_STORE_GPR8	l.sw    0x30(r0),r8
  90#define EMERGENCY_PRINT_LOAD_GPR8	l.lwz   r8,0x30(r0)
  91
  92#define EMERGENCY_PRINT_STORE_GPR9	l.sw    0x34(r0),r9
  93#define EMERGENCY_PRINT_LOAD_GPR9	l.lwz   r9,0x34(r0)
  94
  95#endif
  96
  97/*
  98 * TLB miss handlers temorary stores
  99 */
 100#ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
 101#define EXCEPTION_STORE_GPR2		l.mtspr r0,r2,SPR_SHADOW_GPR(2)
 102#define EXCEPTION_LOAD_GPR2		l.mfspr r2,r0,SPR_SHADOW_GPR(2)
 103
 104#define EXCEPTION_STORE_GPR3		l.mtspr r0,r3,SPR_SHADOW_GPR(3)
 105#define EXCEPTION_LOAD_GPR3		l.mfspr r3,r0,SPR_SHADOW_GPR(3)
 106
 107#define EXCEPTION_STORE_GPR4		l.mtspr r0,r4,SPR_SHADOW_GPR(4)
 108#define EXCEPTION_LOAD_GPR4		l.mfspr r4,r0,SPR_SHADOW_GPR(4)
 109
 110#define EXCEPTION_STORE_GPR5		l.mtspr r0,r5,SPR_SHADOW_GPR(5)
 111#define EXCEPTION_LOAD_GPR5		l.mfspr r5,r0,SPR_SHADOW_GPR(5)
 112
 113#define EXCEPTION_STORE_GPR6		l.mtspr r0,r6,SPR_SHADOW_GPR(6)
 114#define EXCEPTION_LOAD_GPR6		l.mfspr r6,r0,SPR_SHADOW_GPR(6)
 115
 116#else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
 117#define EXCEPTION_STORE_GPR2		l.sw    0x64(r0),r2
 118#define EXCEPTION_LOAD_GPR2		l.lwz   r2,0x64(r0)
 119
 120#define EXCEPTION_STORE_GPR3		l.sw    0x68(r0),r3
 121#define EXCEPTION_LOAD_GPR3		l.lwz   r3,0x68(r0)
 122
 123#define EXCEPTION_STORE_GPR4		l.sw    0x6c(r0),r4
 124#define EXCEPTION_LOAD_GPR4		l.lwz   r4,0x6c(r0)
 125
 126#define EXCEPTION_STORE_GPR5		l.sw    0x70(r0),r5
 127#define EXCEPTION_LOAD_GPR5		l.lwz   r5,0x70(r0)
 128
 129#define EXCEPTION_STORE_GPR6		l.sw    0x74(r0),r6
 130#define EXCEPTION_LOAD_GPR6		l.lwz   r6,0x74(r0)
 131
 132#endif
 133
 134/*
 135 * EXCEPTION_HANDLE temporary stores
 136 */
 137
 138#ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
 139#define EXCEPTION_T_STORE_GPR30		l.mtspr r0,r30,SPR_SHADOW_GPR(30)
 140#define EXCEPTION_T_LOAD_GPR30(reg)	l.mfspr reg,r0,SPR_SHADOW_GPR(30)
 141
 142#define EXCEPTION_T_STORE_GPR10		l.mtspr r0,r10,SPR_SHADOW_GPR(10)
 143#define EXCEPTION_T_LOAD_GPR10(reg)	l.mfspr reg,r0,SPR_SHADOW_GPR(10)
 144
 145#define EXCEPTION_T_STORE_SP		l.mtspr r0,r1,SPR_SHADOW_GPR(1)
 146#define EXCEPTION_T_LOAD_SP(reg)	l.mfspr reg,r0,SPR_SHADOW_GPR(1)
 147
 148#else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
 149#define EXCEPTION_T_STORE_GPR30		l.sw    0x78(r0),r30
 150#define EXCEPTION_T_LOAD_GPR30(reg)	l.lwz   reg,0x78(r0)
 151
 152#define EXCEPTION_T_STORE_GPR10		l.sw    0x7c(r0),r10
 153#define EXCEPTION_T_LOAD_GPR10(reg)	l.lwz   reg,0x7c(r0)
 154
 155#define EXCEPTION_T_STORE_SP		l.sw    0x80(r0),r1
 156#define EXCEPTION_T_LOAD_SP(reg)	l.lwz   reg,0x80(r0)
 157#endif
 158
 159/* =========================================================[ macros ]=== */
 160
 161#ifdef CONFIG_SMP
 162#define GET_CURRENT_PGD(reg,t1)					\
 163	LOAD_SYMBOL_2_GPR(reg,current_pgd)			;\
 164	l.mfspr	t1,r0,SPR_COREID				;\
 165	l.slli	t1,t1,2						;\
 166	l.add	reg,reg,t1					;\
 167	tophys  (t1,reg)					;\
 168	l.lwz   reg,0(t1)
 169#else
 170#define GET_CURRENT_PGD(reg,t1)					\
 171	LOAD_SYMBOL_2_GPR(reg,current_pgd)			;\
 172	tophys  (t1,reg)					;\
 173	l.lwz   reg,0(t1)
 174#endif
 175
 176/* Load r10 from current_thread_info_set - clobbers r1 and r30 */
 177#ifdef CONFIG_SMP
 178#define GET_CURRENT_THREAD_INFO					\
 179	LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)		;\
 180	tophys  (r30,r1)					;\
 181	l.mfspr	r10,r0,SPR_COREID				;\
 182	l.slli	r10,r10,2					;\
 183	l.add	r30,r30,r10					;\
 184	/* r10: current_thread_info  */				;\
 185	l.lwz   r10,0(r30)
 186#else
 187#define GET_CURRENT_THREAD_INFO					\
 188	LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)		;\
 189	tophys  (r30,r1)					;\
 190	/* r10: current_thread_info  */				;\
 191	l.lwz   r10,0(r30)
 192#endif
 193
 194/*
 195 * DSCR: this is a common hook for handling exceptions. it will save
 196 *       the needed registers, set up stack and pointer to current
 197 *	 then jump to the handler while enabling MMU
 198 *
 199 * PRMS: handler	- a function to jump to. it has to save the
 200 *			remaining registers to kernel stack, call
 201 *			appropriate arch-independant exception handler
 202 *			and finaly jump to ret_from_except
 203 *
 204 * PREQ: unchanged state from the time exception happened
 205 *
 206 * POST: SAVED the following registers original value
 207 *	       to the new created exception frame pointed to by r1
 208 *
 209 *	 r1  - ksp	pointing to the new (exception) frame
 210 *	 r4  - EEAR     exception EA
 211 *	 r10 - current	pointing to current_thread_info struct
 212 *	 r12 - syscall  0, since we didn't come from syscall
 213 *	 r13 - temp	it actually contains new SR, not needed anymore
 214 *	 r31 - handler	address of the handler we'll jump to
 215 *
 216 *	 handler has to save remaining registers to the exception
 217 *	 ksp frame *before* tainting them!
 218 *
 219 * NOTE: this function is not reentrant per se. reentrancy is guaranteed
 220 *       by processor disabling all exceptions/interrupts when exception
 221 *	 accours.
 222 *
 223 * OPTM: no need to make it so wasteful to extract ksp when in user mode
 224 */
 225
 226#define EXCEPTION_HANDLE(handler)				\
 227	EXCEPTION_T_STORE_GPR30					;\
 228	l.mfspr r30,r0,SPR_ESR_BASE				;\
 229	l.andi  r30,r30,SPR_SR_SM				;\
 230	l.sfeqi r30,0						;\
 231	EXCEPTION_T_STORE_GPR10					;\
 232	l.bnf   2f                            /* kernel_mode */	;\
 233	 EXCEPTION_T_STORE_SP                 /* delay slot */	;\
 2341: /* user_mode:   */						;\
 235	GET_CURRENT_THREAD_INFO	 				;\
 236	tophys  (r30,r10)					;\
 237	l.lwz   r1,(TI_KSP)(r30)				;\
 238	/* fall through */					;\
 2392: /* kernel_mode: */						;\
 240	/* create new stack frame, save only needed gprs */	;\
 241	/* r1: KSP, r10: current, r4: EEAR, r31: __pa(KSP) */	;\
 242	/* r12:	temp, syscall indicator */			;\
 243	l.addi  r1,r1,-(INT_FRAME_SIZE)				;\
 244	/* r1 is KSP, r30 is __pa(KSP) */			;\
 245	tophys  (r30,r1)					;\
 246	l.sw    PT_GPR12(r30),r12				;\
 
 247	l.mfspr r12,r0,SPR_EPCR_BASE				;\
 248	l.sw    PT_PC(r30),r12					;\
 249	l.mfspr r12,r0,SPR_ESR_BASE				;\
 250	l.sw    PT_SR(r30),r12					;\
 251	/* save r30 */						;\
 252	EXCEPTION_T_LOAD_GPR30(r12)				;\
 253	l.sw	PT_GPR30(r30),r12				;\
 254	/* save r10 as was prior to exception */		;\
 255	EXCEPTION_T_LOAD_GPR10(r12)				;\
 256	l.sw	PT_GPR10(r30),r12				;\
 257	/* save PT_SP as was prior to exception */		;\
 258	EXCEPTION_T_LOAD_SP(r12)				;\
 259	l.sw	PT_SP(r30),r12					;\
 260	/* save exception r4, set r4 = EA */			;\
 261	l.sw	PT_GPR4(r30),r4					;\
 262	l.mfspr r4,r0,SPR_EEAR_BASE				;\
 263	/* r12 == 1 if we come from syscall */			;\
 264	CLEAR_GPR(r12)						;\
 265	/* ----- turn on MMU ----- */				;\
 266	l.ori	r30,r0,(EXCEPTION_SR)				;\
 
 
 
 267	l.mtspr	r0,r30,SPR_ESR_BASE				;\
 268	/* r30:	EA address of handler */			;\
 269	LOAD_SYMBOL_2_GPR(r30,handler)				;\
 270	l.mtspr r0,r30,SPR_EPCR_BASE				;\
 271	l.rfe
 272
 273/*
 274 * this doesn't work
 275 *
 276 *
 277 * #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
 278 * #define UNHANDLED_EXCEPTION(handler)				\
 279 *	l.ori   r3,r0,0x1					;\
 280 *	l.mtspr r0,r3,SPR_SR					;\
 281 *      l.movhi r3,hi(0xf0000100)				;\
 282 *      l.ori   r3,r3,lo(0xf0000100)				;\
 283 *	l.jr	r3						;\
 284 *	l.nop	1
 285 *
 286 * #endif
 287 */
 288
 289/* DSCR: this is the same as EXCEPTION_HANDLE(), we are just
 290 *       a bit more carefull (if we have a PT_SP or current pointer
 291 *       corruption) and set them up from 'current_set'
 292 *
 293 */
 294#define UNHANDLED_EXCEPTION(handler)				\
 295	EXCEPTION_T_STORE_GPR30					;\
 296	EXCEPTION_T_STORE_GPR10					;\
 297	EXCEPTION_T_STORE_SP					;\
 298	/* temporary store r3, r9 into r1, r10 */		;\
 299	l.addi	r1,r3,0x0					;\
 300	l.addi	r10,r9,0x0					;\
 301	/* the string referenced by r3 must be low enough */	;\
 302	l.jal	_emergency_print				;\
 303	l.ori	r3,r0,lo(_string_unhandled_exception)		;\
 304	l.mfspr	r3,r0,SPR_NPC					;\
 305	l.jal	_emergency_print_nr				;\
 306	l.andi	r3,r3,0x1f00					;\
 307	/* the string referenced by r3 must be low enough */	;\
 308	l.jal	_emergency_print				;\
 309	l.ori	r3,r0,lo(_string_epc_prefix)			;\
 310	l.jal	_emergency_print_nr				;\
 311	l.mfspr	r3,r0,SPR_EPCR_BASE				;\
 312	l.jal	_emergency_print				;\
 313	l.ori	r3,r0,lo(_string_nl)				;\
 314	/* end of printing */					;\
 315	l.addi	r3,r1,0x0					;\
 316	l.addi	r9,r10,0x0					;\
 317	/* extract current, ksp from current_set */		;\
 318	LOAD_SYMBOL_2_GPR(r1,_unhandled_stack_top)		;\
 319	LOAD_SYMBOL_2_GPR(r10,init_thread_union)		;\
 320	/* create new stack frame, save only needed gprs */	;\
 321	/* r1: KSP, r10: current, r31: __pa(KSP) */		;\
 322	/* r12:	temp, syscall indicator, r13 temp */		;\
 323	l.addi  r1,r1,-(INT_FRAME_SIZE)				;\
 324	/* r1 is KSP, r30 is __pa(KSP) */			;\
 325	tophys  (r30,r1)					;\
 326	l.sw    PT_GPR12(r30),r12					;\
 327	l.mfspr r12,r0,SPR_EPCR_BASE				;\
 328	l.sw    PT_PC(r30),r12					;\
 329	l.mfspr r12,r0,SPR_ESR_BASE				;\
 330	l.sw    PT_SR(r30),r12					;\
 331	/* save r31 */						;\
 332	EXCEPTION_T_LOAD_GPR30(r12)				;\
 333	l.sw	PT_GPR30(r30),r12					;\
 334	/* save r10 as was prior to exception */		;\
 335	EXCEPTION_T_LOAD_GPR10(r12)				;\
 336	l.sw	PT_GPR10(r30),r12					;\
 337	/* save PT_SP as was prior to exception */			;\
 338	EXCEPTION_T_LOAD_SP(r12)				;\
 339	l.sw	PT_SP(r30),r12					;\
 340	l.sw    PT_GPR13(r30),r13					;\
 341	/* --> */						;\
 342	/* save exception r4, set r4 = EA */			;\
 343	l.sw	PT_GPR4(r30),r4					;\
 344	l.mfspr r4,r0,SPR_EEAR_BASE				;\
 345	/* r12 == 1 if we come from syscall */			;\
 346	CLEAR_GPR(r12)						;\
 347	/* ----- play a MMU trick ----- */			;\
 348	l.ori	r30,r0,(EXCEPTION_SR)				;\
 349	l.mtspr	r0,r30,SPR_ESR_BASE				;\
 350	/* r31:	EA address of handler */			;\
 351	LOAD_SYMBOL_2_GPR(r30,handler)				;\
 352	l.mtspr r0,r30,SPR_EPCR_BASE				;\
 353	l.rfe
 354
 355/* =====================================================[ exceptions] === */
 356
 357/* ---[ 0x100: RESET exception ]----------------------------------------- */
 358    .org 0x100
 359	/* Jump to .init code at _start which lives in the .head section
 360	 * and will be discarded after boot.
 361	 */
 362	LOAD_SYMBOL_2_GPR(r15, _start)
 363	tophys	(r13,r15)			/* MMU disabled */
 364	l.jr	r13
 365	 l.nop
 366
 367/* ---[ 0x200: BUS exception ]------------------------------------------- */
 368    .org 0x200
 369_dispatch_bus_fault:
 370	EXCEPTION_HANDLE(_bus_fault_handler)
 371
 372/* ---[ 0x300: Data Page Fault exception ]------------------------------- */
 373    .org 0x300
 374_dispatch_do_dpage_fault:
 375//      totaly disable timer interrupt
 376// 	l.mtspr	r0,r0,SPR_TTMR
 377//	DEBUG_TLB_PROBE(0x300)
 378//	EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x300)
 379	EXCEPTION_HANDLE(_data_page_fault_handler)
 380
 381/* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
 382    .org 0x400
 383_dispatch_do_ipage_fault:
 384//      totaly disable timer interrupt
 385//	l.mtspr	r0,r0,SPR_TTMR
 386//	DEBUG_TLB_PROBE(0x400)
 387//	EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x400)
 388	EXCEPTION_HANDLE(_insn_page_fault_handler)
 389
 390/* ---[ 0x500: Timer exception ]----------------------------------------- */
 391    .org 0x500
 392	EXCEPTION_HANDLE(_timer_handler)
 393
 394/* ---[ 0x600: Alignment exception ]-------------------------------------- */
 395    .org 0x600
 396	EXCEPTION_HANDLE(_alignment_handler)
 397
 398/* ---[ 0x700: Illegal insn exception ]---------------------------------- */
 399    .org 0x700
 400	EXCEPTION_HANDLE(_illegal_instruction_handler)
 401
 402/* ---[ 0x800: External interrupt exception ]---------------------------- */
 403    .org 0x800
 404	EXCEPTION_HANDLE(_external_irq_handler)
 405
 406/* ---[ 0x900: DTLB miss exception ]------------------------------------- */
 407    .org 0x900
 408	l.j	boot_dtlb_miss_handler
 409	l.nop
 410
 411/* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
 412    .org 0xa00
 413	l.j	boot_itlb_miss_handler
 414	l.nop
 415
 416/* ---[ 0xb00: Range exception ]----------------------------------------- */
 417    .org 0xb00
 418	UNHANDLED_EXCEPTION(_vector_0xb00)
 419
 420/* ---[ 0xc00: Syscall exception ]--------------------------------------- */
 421    .org 0xc00
 422	EXCEPTION_HANDLE(_sys_call_handler)
 423
 424/* ---[ 0xd00: Trap exception ]------------------------------------------ */
 425    .org 0xd00
 426	UNHANDLED_EXCEPTION(_vector_0xd00)
 427
 428/* ---[ 0xe00: Trap exception ]------------------------------------------ */
 429    .org 0xe00
 430//	UNHANDLED_EXCEPTION(_vector_0xe00)
 431	EXCEPTION_HANDLE(_trap_handler)
 432
 433/* ---[ 0xf00: Reserved exception ]-------------------------------------- */
 434    .org 0xf00
 435	UNHANDLED_EXCEPTION(_vector_0xf00)
 436
 437/* ---[ 0x1000: Reserved exception ]------------------------------------- */
 438    .org 0x1000
 439	UNHANDLED_EXCEPTION(_vector_0x1000)
 440
 441/* ---[ 0x1100: Reserved exception ]------------------------------------- */
 442    .org 0x1100
 443	UNHANDLED_EXCEPTION(_vector_0x1100)
 444
 445/* ---[ 0x1200: Reserved exception ]------------------------------------- */
 446    .org 0x1200
 447	UNHANDLED_EXCEPTION(_vector_0x1200)
 448
 449/* ---[ 0x1300: Reserved exception ]------------------------------------- */
 450    .org 0x1300
 451	UNHANDLED_EXCEPTION(_vector_0x1300)
 452
 453/* ---[ 0x1400: Reserved exception ]------------------------------------- */
 454    .org 0x1400
 455	UNHANDLED_EXCEPTION(_vector_0x1400)
 456
 457/* ---[ 0x1500: Reserved exception ]------------------------------------- */
 458    .org 0x1500
 459	UNHANDLED_EXCEPTION(_vector_0x1500)
 460
 461/* ---[ 0x1600: Reserved exception ]------------------------------------- */
 462    .org 0x1600
 463	UNHANDLED_EXCEPTION(_vector_0x1600)
 464
 465/* ---[ 0x1700: Reserved exception ]------------------------------------- */
 466    .org 0x1700
 467	UNHANDLED_EXCEPTION(_vector_0x1700)
 468
 469/* ---[ 0x1800: Reserved exception ]------------------------------------- */
 470    .org 0x1800
 471	UNHANDLED_EXCEPTION(_vector_0x1800)
 472
 473/* ---[ 0x1900: Reserved exception ]------------------------------------- */
 474    .org 0x1900
 475	UNHANDLED_EXCEPTION(_vector_0x1900)
 476
 477/* ---[ 0x1a00: Reserved exception ]------------------------------------- */
 478    .org 0x1a00
 479	UNHANDLED_EXCEPTION(_vector_0x1a00)
 480
 481/* ---[ 0x1b00: Reserved exception ]------------------------------------- */
 482    .org 0x1b00
 483	UNHANDLED_EXCEPTION(_vector_0x1b00)
 484
 485/* ---[ 0x1c00: Reserved exception ]------------------------------------- */
 486    .org 0x1c00
 487	UNHANDLED_EXCEPTION(_vector_0x1c00)
 488
 489/* ---[ 0x1d00: Reserved exception ]------------------------------------- */
 490    .org 0x1d00
 491	UNHANDLED_EXCEPTION(_vector_0x1d00)
 492
 493/* ---[ 0x1e00: Reserved exception ]------------------------------------- */
 494    .org 0x1e00
 495	UNHANDLED_EXCEPTION(_vector_0x1e00)
 496
 497/* ---[ 0x1f00: Reserved exception ]------------------------------------- */
 498    .org 0x1f00
 499	UNHANDLED_EXCEPTION(_vector_0x1f00)
 500
 501    .org 0x2000
 502/* ===================================================[ kernel start ]=== */
 503
 504/*    .text*/
 505
 506/* This early stuff belongs in HEAD, but some of the functions below definitely
 507 * don't... */
 508
 509	__HEAD
 510	.global _start
 511_start:
 512	/* Init r0 to zero as per spec */
 513	CLEAR_GPR(r0)
 514
 515	/* save kernel parameters */
 516	l.or	r25,r0,r3	/* pointer to fdt */
 517
 518	/*
 519	 * ensure a deterministic start
 520	 */
 521
 522	l.ori	r3,r0,0x1
 523	l.mtspr	r0,r3,SPR_SR
 524
 525	CLEAR_GPR(r1)
 526	CLEAR_GPR(r2)
 527	CLEAR_GPR(r3)
 528	CLEAR_GPR(r4)
 529	CLEAR_GPR(r5)
 530	CLEAR_GPR(r6)
 531	CLEAR_GPR(r7)
 532	CLEAR_GPR(r8)
 533	CLEAR_GPR(r9)
 534	CLEAR_GPR(r10)
 535	CLEAR_GPR(r11)
 536	CLEAR_GPR(r12)
 537	CLEAR_GPR(r13)
 538	CLEAR_GPR(r14)
 539	CLEAR_GPR(r15)
 540	CLEAR_GPR(r16)
 541	CLEAR_GPR(r17)
 542	CLEAR_GPR(r18)
 543	CLEAR_GPR(r19)
 544	CLEAR_GPR(r20)
 545	CLEAR_GPR(r21)
 546	CLEAR_GPR(r22)
 547	CLEAR_GPR(r23)
 548	CLEAR_GPR(r24)
 549	CLEAR_GPR(r26)
 550	CLEAR_GPR(r27)
 551	CLEAR_GPR(r28)
 552	CLEAR_GPR(r29)
 553	CLEAR_GPR(r30)
 554	CLEAR_GPR(r31)
 555
 556#ifdef CONFIG_SMP
 557	l.mfspr	r26,r0,SPR_COREID
 558	l.sfeq	r26,r0
 559	l.bnf	secondary_wait
 560	 l.nop
 561#endif
 562	/*
 563	 * set up initial ksp and current
 564	 */
 565	/* setup kernel stack */
 566	LOAD_SYMBOL_2_GPR(r1,init_thread_union + THREAD_SIZE)
 567	LOAD_SYMBOL_2_GPR(r10,init_thread_union)	// setup current
 568	tophys	(r31,r10)
 569	l.sw	TI_KSP(r31), r1
 570
 571	l.ori	r4,r0,0x0
 572
 573
 574	/*
 575	 * .data contains initialized data,
 576	 * .bss contains uninitialized data - clear it up
 577	 */
 578clear_bss:
 579	LOAD_SYMBOL_2_GPR(r24, __bss_start)
 580	LOAD_SYMBOL_2_GPR(r26, _end)
 581	tophys(r28,r24)
 582	tophys(r30,r26)
 583	CLEAR_GPR(r24)
 584	CLEAR_GPR(r26)
 5851:
 586	l.sw    (0)(r28),r0
 587	l.sfltu r28,r30
 588	l.bf    1b
 589	l.addi  r28,r28,4
 590
 591enable_ic:
 592	l.jal	_ic_enable
 593	 l.nop
 594
 595enable_dc:
 596	l.jal	_dc_enable
 597	 l.nop
 598
 599flush_tlb:
 600	l.jal	_flush_tlb
 601	 l.nop
 602
 603/* The MMU needs to be enabled before or32_early_setup is called */
 604
 605enable_mmu:
 606	/*
 607	 * enable dmmu & immu
 608	 * SR[5] = 0, SR[6] = 0, 6th and 7th bit of SR set to 0
 609	 */
 610	l.mfspr	r30,r0,SPR_SR
 611	l.movhi	r28,hi(SPR_SR_DME | SPR_SR_IME)
 612	l.ori	r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 613	l.or	r30,r30,r28
 614	l.mtspr	r0,r30,SPR_SR
 615	l.nop
 616	l.nop
 617	l.nop
 618	l.nop
 619	l.nop
 620	l.nop
 621	l.nop
 622	l.nop
 623	l.nop
 624	l.nop
 625	l.nop
 626	l.nop
 627	l.nop
 628	l.nop
 629	l.nop
 630	l.nop
 631
 632	// reset the simulation counters
 633	l.nop 5
 634
 635	/* check fdt header magic word */
 636	l.lwz	r3,0(r25)	/* load magic from fdt into r3 */
 637	l.movhi	r4,hi(OF_DT_HEADER)
 638	l.ori	r4,r4,lo(OF_DT_HEADER)
 639	l.sfeq	r3,r4
 640	l.bf	_fdt_found
 641	 l.nop
 642	/* magic number mismatch, set fdt pointer to null */
 643	l.or	r25,r0,r0
 644_fdt_found:
 645	/* pass fdt pointer to or32_early_setup in r3 */
 646	l.or	r3,r0,r25
 647	LOAD_SYMBOL_2_GPR(r24, or32_early_setup)
 648	l.jalr r24
 649	 l.nop
 650
 651clear_regs:
 652	/*
 653	 * clear all GPRS to increase determinism
 654	 */
 655	CLEAR_GPR(r2)
 656	CLEAR_GPR(r3)
 657	CLEAR_GPR(r4)
 658	CLEAR_GPR(r5)
 659	CLEAR_GPR(r6)
 660	CLEAR_GPR(r7)
 661	CLEAR_GPR(r8)
 662	CLEAR_GPR(r9)
 663	CLEAR_GPR(r11)
 664	CLEAR_GPR(r12)
 665	CLEAR_GPR(r13)
 666	CLEAR_GPR(r14)
 667	CLEAR_GPR(r15)
 668	CLEAR_GPR(r16)
 669	CLEAR_GPR(r17)
 670	CLEAR_GPR(r18)
 671	CLEAR_GPR(r19)
 672	CLEAR_GPR(r20)
 673	CLEAR_GPR(r21)
 674	CLEAR_GPR(r22)
 675	CLEAR_GPR(r23)
 676	CLEAR_GPR(r24)
 677	CLEAR_GPR(r25)
 678	CLEAR_GPR(r26)
 679	CLEAR_GPR(r27)
 680	CLEAR_GPR(r28)
 681	CLEAR_GPR(r29)
 682	CLEAR_GPR(r30)
 683	CLEAR_GPR(r31)
 684
 685jump_start_kernel:
 686	/*
 687	 * jump to kernel entry (start_kernel)
 688	 */
 689	LOAD_SYMBOL_2_GPR(r30, start_kernel)
 690	l.jr    r30
 691	 l.nop
 692
 693_flush_tlb:
 694	/*
 695	 *  I N V A L I D A T E   T L B   e n t r i e s
 696	 */
 697	LOAD_SYMBOL_2_GPR(r5,SPR_DTLBMR_BASE(0))
 698	LOAD_SYMBOL_2_GPR(r6,SPR_ITLBMR_BASE(0))
 699	l.addi	r7,r0,128 /* Maximum number of sets */
 7001:
 701	l.mtspr	r5,r0,0x0
 702	l.mtspr	r6,r0,0x0
 703
 704	l.addi	r5,r5,1
 705	l.addi	r6,r6,1
 706	l.sfeq	r7,r0
 707	l.bnf	1b
 708	 l.addi	r7,r7,-1
 709
 710	l.jr	r9
 711	 l.nop
 712
 713#ifdef CONFIG_SMP
 714secondary_wait:
 715	/* Doze the cpu until we are asked to run */
 716	/* If we dont have power management skip doze */
 717	l.mfspr r25,r0,SPR_UPR
 718	l.andi  r25,r25,SPR_UPR_PMP
 719	l.sfeq  r25,r0
 720	l.bf	secondary_check_release
 721	 l.nop
 722
 723	/* Setup special secondary exception handler */
 724	LOAD_SYMBOL_2_GPR(r3, _secondary_evbar)
 725	tophys(r25,r3)
 726	l.mtspr	r0,r25,SPR_EVBAR
 727
 728	/* Enable Interrupts */
 729	l.mfspr	r25,r0,SPR_SR
 730	l.ori	r25,r25,SPR_SR_IEE
 731	l.mtspr	r0,r25,SPR_SR
 732
 733	/* Unmask interrupts interrupts */
 734	l.mfspr r25,r0,SPR_PICMR
 735	l.ori   r25,r25,0xffff
 736	l.mtspr	r0,r25,SPR_PICMR
 737
 738	/* Doze */
 739	l.mfspr r25,r0,SPR_PMR
 740	LOAD_SYMBOL_2_GPR(r3, SPR_PMR_DME)
 741	l.or    r25,r25,r3
 742	l.mtspr r0,r25,SPR_PMR
 743
 744	/* Wakeup - Restore exception handler */
 745	l.mtspr	r0,r0,SPR_EVBAR
 746
 747secondary_check_release:
 748	/*
 749	 * Check if we actually got the release signal, if not go-back to
 750	 * sleep.
 751	 */
 752	l.mfspr	r25,r0,SPR_COREID
 753	LOAD_SYMBOL_2_GPR(r3, secondary_release)
 754	tophys(r4, r3)
 755	l.lwz	r3,0(r4)
 756	l.sfeq	r25,r3
 757	l.bnf	secondary_wait
 758	 l.nop
 759	/* fall through to secondary_init */
 760
 761secondary_init:
 762	/*
 763	 * set up initial ksp and current
 764	 */
 765	LOAD_SYMBOL_2_GPR(r10, secondary_thread_info)
 766	tophys	(r30,r10)
 767	l.lwz	r10,0(r30)
 768	l.addi	r1,r10,THREAD_SIZE
 769	tophys	(r30,r10)
 770	l.sw	TI_KSP(r30),r1
 771
 772	l.jal	_ic_enable
 773	 l.nop
 774
 775	l.jal	_dc_enable
 776	 l.nop
 777
 778	l.jal	_flush_tlb
 779	 l.nop
 780
 781	/*
 782	 * enable dmmu & immu
 783	 */
 784	l.mfspr	r30,r0,SPR_SR
 785	l.movhi	r28,hi(SPR_SR_DME | SPR_SR_IME)
 786	l.ori	r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 787	l.or	r30,r30,r28
 788	/*
 789	 * This is a bit tricky, we need to switch over from physical addresses
 790	 * to virtual addresses on the fly.
 791	 * To do that, we first set up ESR with the IME and DME bits set.
 792	 * Then EPCR is set to secondary_start and then a l.rfe is issued to
 793	 * "jump" to that.
 794	 */
 795	l.mtspr	r0,r30,SPR_ESR_BASE
 796	LOAD_SYMBOL_2_GPR(r30, secondary_start)
 797	l.mtspr	r0,r30,SPR_EPCR_BASE
 798	l.rfe
 799
 800secondary_start:
 801	LOAD_SYMBOL_2_GPR(r30, secondary_start_kernel)
 802	l.jr    r30
 803	 l.nop
 804
 805#endif
 806
 807/* ========================================[ cache ]=== */
 808
 809	/* alignment here so we don't change memory offsets with
 810	 * memory controller defined
 811	 */
 812	.align 0x2000
 813
 814_ic_enable:
 815	/* Check if IC present and skip enabling otherwise */
 816	l.mfspr r24,r0,SPR_UPR
 817	l.andi  r26,r24,SPR_UPR_ICP
 818	l.sfeq  r26,r0
 819	l.bf	9f
 820	l.nop
 821
 822	/* Disable IC */
 823	l.mfspr r6,r0,SPR_SR
 824	l.addi  r5,r0,-1
 825	l.xori  r5,r5,SPR_SR_ICE
 826	l.and   r5,r6,r5
 827	l.mtspr r0,r5,SPR_SR
 828
 829	/* Establish cache block size
 830	   If BS=0, 16;
 831	   If BS=1, 32;
 832	   r14 contain block size
 833	*/
 834	l.mfspr r24,r0,SPR_ICCFGR
 835	l.andi	r26,r24,SPR_ICCFGR_CBS
 836	l.srli	r28,r26,7
 837	l.ori	r30,r0,16
 838	l.sll	r14,r30,r28
 839
 840	/* Establish number of cache sets
 841	   r16 contains number of cache sets
 842	   r28 contains log(# of cache sets)
 843	*/
 844	l.andi  r26,r24,SPR_ICCFGR_NCS
 845	l.srli 	r28,r26,3
 846	l.ori   r30,r0,1
 847	l.sll   r16,r30,r28
 848
 849	/* Invalidate IC */
 850	l.addi  r6,r0,0
 851	l.sll   r5,r14,r28
 852//        l.mul   r5,r14,r16
 853//	l.trap  1
 854//	l.addi  r5,r0,IC_SIZE
 8551:
 856	l.mtspr r0,r6,SPR_ICBIR
 857	l.sfne  r6,r5
 858	l.bf    1b
 859	l.add   r6,r6,r14
 860 //       l.addi   r6,r6,IC_LINE
 861
 862	/* Enable IC */
 863	l.mfspr r6,r0,SPR_SR
 864	l.ori   r6,r6,SPR_SR_ICE
 865	l.mtspr r0,r6,SPR_SR
 866	l.nop
 867	l.nop
 868	l.nop
 869	l.nop
 870	l.nop
 871	l.nop
 872	l.nop
 873	l.nop
 874	l.nop
 875	l.nop
 8769:
 877	l.jr    r9
 878	l.nop
 879
 880_dc_enable:
 881	/* Check if DC present and skip enabling otherwise */
 882	l.mfspr r24,r0,SPR_UPR
 883	l.andi  r26,r24,SPR_UPR_DCP
 884	l.sfeq  r26,r0
 885	l.bf	9f
 886	l.nop
 887
 888	/* Disable DC */
 889	l.mfspr r6,r0,SPR_SR
 890	l.addi  r5,r0,-1
 891	l.xori  r5,r5,SPR_SR_DCE
 892	l.and   r5,r6,r5
 893	l.mtspr r0,r5,SPR_SR
 894
 895	/* Establish cache block size
 896	   If BS=0, 16;
 897	   If BS=1, 32;
 898	   r14 contain block size
 899	*/
 900	l.mfspr r24,r0,SPR_DCCFGR
 901	l.andi	r26,r24,SPR_DCCFGR_CBS
 902	l.srli	r28,r26,7
 903	l.ori	r30,r0,16
 904	l.sll	r14,r30,r28
 905
 906	/* Establish number of cache sets
 907	   r16 contains number of cache sets
 908	   r28 contains log(# of cache sets)
 909	*/
 910	l.andi  r26,r24,SPR_DCCFGR_NCS
 911	l.srli 	r28,r26,3
 912	l.ori   r30,r0,1
 913	l.sll   r16,r30,r28
 914
 915	/* Invalidate DC */
 916	l.addi  r6,r0,0
 917	l.sll   r5,r14,r28
 9181:
 919	l.mtspr r0,r6,SPR_DCBIR
 920	l.sfne  r6,r5
 921	l.bf    1b
 922	l.add   r6,r6,r14
 923
 924	/* Enable DC */
 925	l.mfspr r6,r0,SPR_SR
 926	l.ori   r6,r6,SPR_SR_DCE
 927	l.mtspr r0,r6,SPR_SR
 9289:
 929	l.jr    r9
 930	l.nop
 931
 932/* ===============================================[ page table masks ]=== */
 933
 934#define DTLB_UP_CONVERT_MASK  0x3fa
 935#define ITLB_UP_CONVERT_MASK  0x3a
 936
 937/* for SMP we'd have (this is a bit subtle, CC must be always set
 938 * for SMP, but since we have _PAGE_PRESENT bit always defined
 939 * we can just modify the mask)
 940 */
 941#define DTLB_SMP_CONVERT_MASK  0x3fb
 942#define ITLB_SMP_CONVERT_MASK  0x3b
 943
 944/* ---[ boot dtlb miss handler ]----------------------------------------- */
 945
 946boot_dtlb_miss_handler:
 947
 948/* mask for DTLB_MR register: - (0) sets V (valid) bit,
 949 *                            - (31-12) sets bits belonging to VPN (31-12)
 950 */
 951#define DTLB_MR_MASK 0xfffff001
 952
 953/* mask for DTLB_TR register: - (2) sets CI (cache inhibit) bit,
 954 *			      - (4) sets A (access) bit,
 955 *                            - (5) sets D (dirty) bit,
 956 *                            - (8) sets SRE (superuser read) bit
 957 *                            - (9) sets SWE (superuser write) bit
 958 *                            - (31-12) sets bits belonging to VPN (31-12)
 959 */
 960#define DTLB_TR_MASK 0xfffff332
 961
 962/* These are for masking out the VPN/PPN value from the MR/TR registers...
 963 * it's not the same as the PFN */
 964#define VPN_MASK 0xfffff000
 965#define PPN_MASK 0xfffff000
 966
 967
 968	EXCEPTION_STORE_GPR6
 969
 970#if 0
 971	l.mfspr r6,r0,SPR_ESR_BASE	   //
 972	l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
 973	l.sfeqi r6,0                       // r6 == 0x1 --> SM
 974	l.bf    exit_with_no_dtranslation  //
 975	l.nop
 976#endif
 977
 978	/* this could be optimized by moving storing of
 979	 * non r6 registers here, and jumping r6 restore
 980	 * if not in supervisor mode
 981	 */
 982
 983	EXCEPTION_STORE_GPR2
 984	EXCEPTION_STORE_GPR3
 985	EXCEPTION_STORE_GPR4
 986	EXCEPTION_STORE_GPR5
 987
 988	l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
 989
 990immediate_translation:
 991	CLEAR_GPR(r6)
 992
 993	l.srli	r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
 994
 995	l.mfspr r6, r0, SPR_DMMUCFGR
 996	l.andi	r6, r6, SPR_DMMUCFGR_NTS
 997	l.srli	r6, r6, SPR_DMMUCFGR_NTS_OFF
 998	l.ori	r5, r0, 0x1
 999	l.sll	r5, r5, r6 	// r5 = number DMMU sets
1000	l.addi	r6, r5, -1  	// r6 = nsets mask
1001	l.and	r2, r3, r6	// r2 <- r3 % NSETS_MASK
1002
1003	l.or    r6,r6,r4                   // r6 <- r4
1004	l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
1005	l.movhi r5,hi(DTLB_MR_MASK)        // r5 <- ffff:0000.x000
1006	l.ori   r5,r5,lo(DTLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply DTLB_MR_MASK
1007	l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have DTLBMR entry
1008	l.mtspr r2,r5,SPR_DTLBMR_BASE(0)   // set DTLBMR
1009
1010	/* set up DTLB with no translation for EA <= 0xbfffffff */
1011	LOAD_SYMBOL_2_GPR(r6,0xbfffffff)
1012	l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xbfffffff >= EA)
1013	l.bf     1f                        // goto out
1014	l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
1015
1016	tophys(r3,r4)                      // r3 <- PA
10171:
1018	l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
1019	l.movhi r5,hi(DTLB_TR_MASK)        // r5 <- ffff:0000.x000
1020	l.ori   r5,r5,lo(DTLB_TR_MASK)     // r5 <- ffff:1111.x330 - apply DTLB_MR_MASK
1021	l.and   r5,r5,r3                   // r5 <- PPN :PPN .x330 - we have DTLBTR entry
1022	l.mtspr r2,r5,SPR_DTLBTR_BASE(0)   // set DTLBTR
1023
1024	EXCEPTION_LOAD_GPR6
1025	EXCEPTION_LOAD_GPR5
1026	EXCEPTION_LOAD_GPR4
1027	EXCEPTION_LOAD_GPR3
1028	EXCEPTION_LOAD_GPR2
1029
1030	l.rfe                              // SR <- ESR, PC <- EPC
1031
1032exit_with_no_dtranslation:
1033	/* EA out of memory or not in supervisor mode */
1034	EXCEPTION_LOAD_GPR6
1035	EXCEPTION_LOAD_GPR4
1036	l.j	_dispatch_bus_fault
1037
1038/* ---[ boot itlb miss handler ]----------------------------------------- */
1039
1040boot_itlb_miss_handler:
1041
1042/* mask for ITLB_MR register: - sets V (valid) bit,
1043 *                            - sets bits belonging to VPN (15-12)
1044 */
1045#define ITLB_MR_MASK 0xfffff001
1046
1047/* mask for ITLB_TR register: - sets A (access) bit,
1048 *                            - sets SXE (superuser execute) bit
1049 *                            - sets bits belonging to VPN (15-12)
1050 */
1051#define ITLB_TR_MASK 0xfffff050
1052
1053/*
1054#define VPN_MASK 0xffffe000
1055#define PPN_MASK 0xffffe000
1056*/
1057
1058
1059
1060	EXCEPTION_STORE_GPR2
1061	EXCEPTION_STORE_GPR3
1062	EXCEPTION_STORE_GPR4
1063	EXCEPTION_STORE_GPR5
1064	EXCEPTION_STORE_GPR6
1065
1066#if 0
1067	l.mfspr r6,r0,SPR_ESR_BASE         //
1068	l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
1069	l.sfeqi r6,0                       // r6 == 0x1 --> SM
1070	l.bf    exit_with_no_itranslation
1071	l.nop
1072#endif
1073
1074
1075	l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
1076
1077earlyearly:
1078	CLEAR_GPR(r6)
1079
1080	l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
1081
1082	l.mfspr r6, r0, SPR_IMMUCFGR
1083	l.andi	r6, r6, SPR_IMMUCFGR_NTS
1084	l.srli	r6, r6, SPR_IMMUCFGR_NTS_OFF
1085	l.ori	r5, r0, 0x1
1086	l.sll	r5, r5, r6 	// r5 = number IMMU sets from IMMUCFGR
1087	l.addi	r6, r5, -1  	// r6 = nsets mask
1088	l.and	r2, r3, r6	// r2 <- r3 % NSETS_MASK
1089
1090	l.or    r6,r6,r4                   // r6 <- r4
1091	l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
1092	l.movhi r5,hi(ITLB_MR_MASK)        // r5 <- ffff:0000.x000
1093	l.ori   r5,r5,lo(ITLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply ITLB_MR_MASK
1094	l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have ITLBMR entry
1095	l.mtspr r2,r5,SPR_ITLBMR_BASE(0)   // set ITLBMR
1096
1097	/*
1098	 * set up ITLB with no translation for EA <= 0x0fffffff
1099	 *
1100	 * we need this for head.S mapping (EA = PA). if we move all functions
1101	 * which run with mmu enabled into entry.S, we might be able to eliminate this.
1102	 *
1103	 */
1104	LOAD_SYMBOL_2_GPR(r6,0x0fffffff)
1105	l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xb0ffffff >= EA)
1106	l.bf     1f                        // goto out
1107	l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
1108
1109	tophys(r3,r4)                      // r3 <- PA
11101:
1111	l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
1112	l.movhi r5,hi(ITLB_TR_MASK)        // r5 <- ffff:0000.x000
1113	l.ori   r5,r5,lo(ITLB_TR_MASK)     // r5 <- ffff:1111.x050 - apply ITLB_MR_MASK
1114	l.and   r5,r5,r3                   // r5 <- PPN :PPN .x050 - we have ITLBTR entry
1115	l.mtspr r2,r5,SPR_ITLBTR_BASE(0)   // set ITLBTR
1116
1117	EXCEPTION_LOAD_GPR6
1118	EXCEPTION_LOAD_GPR5
1119	EXCEPTION_LOAD_GPR4
1120	EXCEPTION_LOAD_GPR3
1121	EXCEPTION_LOAD_GPR2
1122
1123	l.rfe                              // SR <- ESR, PC <- EPC
1124
1125exit_with_no_itranslation:
1126	EXCEPTION_LOAD_GPR4
1127	EXCEPTION_LOAD_GPR6
1128	l.j    _dispatch_bus_fault
1129	l.nop
1130
1131/* ====================================================================== */
1132/*
1133 * Stuff below here shouldn't go into .head section... maybe this stuff
1134 * can be moved to entry.S ???
1135 */
1136
1137/* ==============================================[ DTLB miss handler ]=== */
1138
1139/*
1140 * Comments:
1141 *   Exception handlers are entered with MMU off so the following handler
1142 *   needs to use physical addressing
1143 *
1144 */
1145
1146	.text
1147ENTRY(dtlb_miss_handler)
1148	EXCEPTION_STORE_GPR2
1149	EXCEPTION_STORE_GPR3
1150	EXCEPTION_STORE_GPR4
1151	/*
1152	 * get EA of the miss
1153	 */
1154	l.mfspr	r2,r0,SPR_EEAR_BASE
1155	/*
1156	 * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1157	 */
1158	GET_CURRENT_PGD(r3,r4)		// r3 is current_pgd, r4 is temp
1159	l.srli	r4,r2,0x18		// >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1160	l.slli	r4,r4,0x2		// to get address << 2
1161	l.add	r3,r4,r3		// r4 is pgd_index(daddr)
1162	/*
1163	 * if (pmd_none(*pmd))
1164	 *   goto pmd_none:
1165	 */
1166	tophys	(r4,r3)
1167	l.lwz	r3,0x0(r4)		// get *pmd value
1168	l.sfne	r3,r0
1169	l.bnf	d_pmd_none
1170	 l.addi	r3,r0,0xffffe000	// PAGE_MASK
1171
1172d_pmd_good:
1173	/*
1174	 * pte = *pte_offset(pmd, daddr);
1175	 */
1176	l.lwz	r4,0x0(r4)		// get **pmd value
1177	l.and	r4,r4,r3		// & PAGE_MASK
1178	l.srli	r2,r2,0xd		// >> PAGE_SHIFT, r2 == EEAR
1179	l.andi	r3,r2,0x7ff		// (1UL << PAGE_SHIFT - 2) - 1
1180	l.slli	r3,r3,0x2		// to get address << 2
1181	l.add	r3,r3,r4
1182	l.lwz	r3,0x0(r3)		// this is pte at last
1183	/*
1184	 * if (!pte_present(pte))
1185	 */
1186	l.andi	r4,r3,0x1
1187	l.sfne	r4,r0			// is pte present
1188	l.bnf	d_pte_not_present
1189	l.addi	r4,r0,0xffffe3fa	// PAGE_MASK | DTLB_UP_CONVERT_MASK
1190	/*
1191	 * fill DTLB TR register
1192	 */
1193	l.and	r4,r3,r4		// apply the mask
1194	// Determine number of DMMU sets
1195	l.mfspr r2, r0, SPR_DMMUCFGR
1196	l.andi	r2, r2, SPR_DMMUCFGR_NTS
1197	l.srli	r2, r2, SPR_DMMUCFGR_NTS_OFF
1198	l.ori	r3, r0, 0x1
1199	l.sll	r3, r3, r2 	// r3 = number DMMU sets DMMUCFGR
1200	l.addi	r2, r3, -1  	// r2 = nsets mask
1201	l.mfspr	r3, r0, SPR_EEAR_BASE
1202	l.srli	r3, r3, 0xd	// >> PAGE_SHIFT
1203	l.and	r2, r3, r2	// calc offset:	 & (NUM_TLB_ENTRIES-1)
1204	                                                   //NUM_TLB_ENTRIES
1205	l.mtspr	r2,r4,SPR_DTLBTR_BASE(0)
1206	/*
1207	 * fill DTLB MR register
1208	 */
1209	l.slli	r3, r3, 0xd		/* << PAGE_SHIFT => EA & PAGE_MASK */
1210	l.ori	r4,r3,0x1		// set hardware valid bit: DTBL_MR entry
1211	l.mtspr	r2,r4,SPR_DTLBMR_BASE(0)
1212
1213	EXCEPTION_LOAD_GPR2
1214	EXCEPTION_LOAD_GPR3
1215	EXCEPTION_LOAD_GPR4
1216	l.rfe
1217d_pmd_none:
1218d_pte_not_present:
1219	EXCEPTION_LOAD_GPR2
1220	EXCEPTION_LOAD_GPR3
1221	EXCEPTION_LOAD_GPR4
1222	EXCEPTION_HANDLE(_dtlb_miss_page_fault_handler)
1223
1224/* ==============================================[ ITLB miss handler ]=== */
1225ENTRY(itlb_miss_handler)
1226	EXCEPTION_STORE_GPR2
1227	EXCEPTION_STORE_GPR3
1228	EXCEPTION_STORE_GPR4
1229	/*
1230	 * get EA of the miss
1231	 */
1232	l.mfspr	r2,r0,SPR_EEAR_BASE
1233
1234	/*
1235	 * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1236	 *
1237	 */
1238	GET_CURRENT_PGD(r3,r4)		// r3 is current_pgd, r5 is temp
1239	l.srli	r4,r2,0x18		// >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1240	l.slli	r4,r4,0x2		// to get address << 2
1241	l.add	r3,r4,r3		// r4 is pgd_index(daddr)
1242	/*
1243	 * if (pmd_none(*pmd))
1244	 *   goto pmd_none:
1245	 */
1246	tophys	(r4,r3)
1247	l.lwz	r3,0x0(r4)		// get *pmd value
1248	l.sfne	r3,r0
1249	l.bnf	i_pmd_none
1250	 l.addi	r3,r0,0xffffe000	// PAGE_MASK
1251
1252i_pmd_good:
1253	/*
1254	 * pte = *pte_offset(pmd, iaddr);
1255	 *
1256	 */
1257	l.lwz	r4,0x0(r4)		// get **pmd value
1258	l.and	r4,r4,r3		// & PAGE_MASK
1259	l.srli	r2,r2,0xd		// >> PAGE_SHIFT, r2 == EEAR
1260	l.andi	r3,r2,0x7ff		// (1UL << PAGE_SHIFT - 2) - 1
1261	l.slli	r3,r3,0x2		// to get address << 2
1262	l.add	r3,r3,r4
1263	l.lwz	r3,0x0(r3)		// this is pte at last
1264	/*
1265	 * if (!pte_present(pte))
1266	 *
1267	 */
1268	l.andi	r4,r3,0x1
1269	l.sfne	r4,r0			// is pte present
1270	l.bnf	i_pte_not_present
1271	 l.addi	r4,r0,0xffffe03a	// PAGE_MASK | ITLB_UP_CONVERT_MASK
1272	/*
1273	 * fill ITLB TR register
1274	 */
1275	l.and	r4,r3,r4		// apply the mask
1276	l.andi	r3,r3,0x7c0		// _PAGE_EXEC | _PAGE_SRE | _PAGE_SWE |  _PAGE_URE | _PAGE_UWE
1277	l.sfeq	r3,r0
1278	l.bf	itlb_tr_fill //_workaround
1279	// Determine number of IMMU sets
1280	l.mfspr r2, r0, SPR_IMMUCFGR
1281	l.andi	r2, r2, SPR_IMMUCFGR_NTS
1282	l.srli	r2, r2, SPR_IMMUCFGR_NTS_OFF
1283	l.ori	r3, r0, 0x1
1284	l.sll	r3, r3, r2 	// r3 = number IMMU sets IMMUCFGR
1285	l.addi	r2, r3, -1  	// r2 = nsets mask
1286	l.mfspr	r3, r0, SPR_EEAR_BASE
1287	l.srli	r3, r3, 0xd	// >> PAGE_SHIFT
1288	l.and	r2, r3, r2	// calc offset:	 & (NUM_TLB_ENTRIES-1)
1289
1290/*
1291 * __PHX__ :: fixme
1292 * we should not just blindly set executable flags,
1293 * but it does help with ping. the clean way would be to find out
1294 * (and fix it) why stack doesn't have execution permissions
1295 */
1296
1297itlb_tr_fill_workaround:
1298	l.ori	r4,r4,0xc0		// | (SPR_ITLBTR_UXE | ITLBTR_SXE)
1299itlb_tr_fill:
1300	l.mtspr	r2,r4,SPR_ITLBTR_BASE(0)
1301	/*
1302	 * fill DTLB MR register
1303	 */
1304	l.slli	r3, r3, 0xd		/* << PAGE_SHIFT => EA & PAGE_MASK */
1305	l.ori	r4,r3,0x1		// set hardware valid bit: ITBL_MR entry
1306	l.mtspr	r2,r4,SPR_ITLBMR_BASE(0)
1307
1308	EXCEPTION_LOAD_GPR2
1309	EXCEPTION_LOAD_GPR3
1310	EXCEPTION_LOAD_GPR4
1311	l.rfe
1312
1313i_pmd_none:
1314i_pte_not_present:
1315	EXCEPTION_LOAD_GPR2
1316	EXCEPTION_LOAD_GPR3
1317	EXCEPTION_LOAD_GPR4
1318	EXCEPTION_HANDLE(_itlb_miss_page_fault_handler)
1319
1320/* ==============================================[ boot tlb handlers ]=== */
1321
1322
1323/* =================================================[ debugging aids ]=== */
1324
1325	.align 64
1326_immu_trampoline:
1327	.space 64
1328_immu_trampoline_top:
1329
1330#define TRAMP_SLOT_0		(0x0)
1331#define TRAMP_SLOT_1		(0x4)
1332#define TRAMP_SLOT_2		(0x8)
1333#define TRAMP_SLOT_3		(0xc)
1334#define TRAMP_SLOT_4		(0x10)
1335#define TRAMP_SLOT_5		(0x14)
1336#define TRAMP_FRAME_SIZE	(0x18)
1337
1338ENTRY(_immu_trampoline_workaround)
1339	// r2 EEA
1340	// r6 is physical EEA
1341	tophys(r6,r2)
1342
1343	LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
1344	tophys	(r3,r5)			// r3 is trampoline (physical)
1345
1346	LOAD_SYMBOL_2_GPR(r4,0x15000000)
1347	l.sw	TRAMP_SLOT_0(r3),r4
1348	l.sw	TRAMP_SLOT_1(r3),r4
1349	l.sw	TRAMP_SLOT_4(r3),r4
1350	l.sw	TRAMP_SLOT_5(r3),r4
1351
1352					// EPC = EEA - 0x4
1353	l.lwz	r4,0x0(r6)		// load op @ EEA + 0x0 (fc address)
1354	l.sw	TRAMP_SLOT_3(r3),r4	// store it to _immu_trampoline_data
1355	l.lwz	r4,-0x4(r6)		// load op @ EEA - 0x4 (f8 address)
1356	l.sw	TRAMP_SLOT_2(r3),r4	// store it to _immu_trampoline_data
1357
1358	l.srli  r5,r4,26                // check opcode for write access
1359	l.sfeqi r5,0                    // l.j
1360	l.bf    0f
1361	l.sfeqi r5,0x11                 // l.jr
1362	l.bf    1f
1363	l.sfeqi r5,1                    // l.jal
1364	l.bf    2f
1365	l.sfeqi r5,0x12                 // l.jalr
1366	l.bf    3f
1367	l.sfeqi r5,3                    // l.bnf
1368	l.bf    4f
1369	l.sfeqi r5,4                    // l.bf
1370	l.bf    5f
137199:
1372	l.nop
1373	l.j	99b			// should never happen
1374	l.nop	1
1375
1376	// r2 is EEA
1377	// r3 is trampoline address (physical)
1378	// r4 is instruction
1379	// r6 is physical(EEA)
1380	//
1381	// r5
1382
13832:	// l.jal
1384
1385	/* 19 20 aa aa	l.movhi r9,0xaaaa
1386	 * a9 29 bb bb  l.ori	r9,0xbbbb
1387	 *
1388	 * where 0xaaaabbbb is EEA + 0x4 shifted right 2
1389	 */
1390
1391	l.addi	r6,r2,0x4		// this is 0xaaaabbbb
1392
1393					// l.movhi r9,0xaaaa
1394	l.ori	r5,r0,0x1920		// 0x1920 == l.movhi r9
1395	l.sh	(TRAMP_SLOT_0+0x0)(r3),r5
1396	l.srli	r5,r6,16
1397	l.sh	(TRAMP_SLOT_0+0x2)(r3),r5
1398
1399					// l.ori   r9,0xbbbb
1400	l.ori	r5,r0,0xa929		// 0xa929 == l.ori r9
1401	l.sh	(TRAMP_SLOT_1+0x0)(r3),r5
1402	l.andi	r5,r6,0xffff
1403	l.sh	(TRAMP_SLOT_1+0x2)(r3),r5
1404
1405	/* falthrough, need to set up new jump offset */
1406
1407
14080:	// l.j
1409	l.slli	r6,r4,6			// original offset shifted left 6 - 2
1410//	l.srli	r6,r6,6			// original offset shifted right 2
1411
1412	l.slli	r4,r2,4			// old jump position: EEA shifted left 4
1413//	l.srli	r4,r4,6			// old jump position: shifted right 2
1414
1415	l.addi	r5,r3,0xc		// new jump position (physical)
1416	l.slli	r5,r5,4			// new jump position: shifted left 4
1417
1418	// calculate new jump offset
1419	// new_off = old_off + (old_jump - new_jump)
1420
1421	l.sub	r5,r4,r5		// old_jump - new_jump
1422	l.add	r5,r6,r5		// orig_off + (old_jump - new_jump)
1423	l.srli	r5,r5,6			// new offset shifted right 2
1424
1425	// r5 is new jump offset
1426					// l.j has opcode 0x0...
1427	l.sw	TRAMP_SLOT_2(r3),r5	// write it back
1428
1429	l.j	trampoline_out
1430	l.nop
1431
1432/* ----------------------------- */
1433
14343:	// l.jalr
1435
1436	/* 19 20 aa aa	l.movhi r9,0xaaaa
1437	 * a9 29 bb bb  l.ori	r9,0xbbbb
1438	 *
1439	 * where 0xaaaabbbb is EEA + 0x4 shifted right 2
1440	 */
1441
1442	l.addi	r6,r2,0x4		// this is 0xaaaabbbb
1443
1444					// l.movhi r9,0xaaaa
1445	l.ori	r5,r0,0x1920		// 0x1920 == l.movhi r9
1446	l.sh	(TRAMP_SLOT_0+0x0)(r3),r5
1447	l.srli	r5,r6,16
1448	l.sh	(TRAMP_SLOT_0+0x2)(r3),r5
1449
1450					// l.ori   r9,0xbbbb
1451	l.ori	r5,r0,0xa929		// 0xa929 == l.ori r9
1452	l.sh	(TRAMP_SLOT_1+0x0)(r3),r5
1453	l.andi	r5,r6,0xffff
1454	l.sh	(TRAMP_SLOT_1+0x2)(r3),r5
1455
1456	l.lhz	r5,(TRAMP_SLOT_2+0x0)(r3)	// load hi part of jump instruction
1457	l.andi	r5,r5,0x3ff		// clear out opcode part
1458	l.ori	r5,r5,0x4400		// opcode changed from l.jalr -> l.jr
1459	l.sh	(TRAMP_SLOT_2+0x0)(r3),r5 // write it back
1460
1461	/* falthrough */
1462
14631:	// l.jr
1464	l.j	trampoline_out
1465	l.nop
1466
1467/* ----------------------------- */
1468
14694:	// l.bnf
14705:	// l.bf
1471	l.slli	r6,r4,6			// original offset shifted left 6 - 2
1472//	l.srli	r6,r6,6			// original offset shifted right 2
1473
1474	l.slli	r4,r2,4			// old jump position: EEA shifted left 4
1475//	l.srli	r4,r4,6			// old jump position: shifted right 2
1476
1477	l.addi	r5,r3,0xc		// new jump position (physical)
1478	l.slli	r5,r5,4			// new jump position: shifted left 4
1479
1480	// calculate new jump offset
1481	// new_off = old_off + (old_jump - new_jump)
1482
1483	l.add	r6,r6,r4		// (orig_off + old_jump)
1484	l.sub	r6,r6,r5		// (orig_off + old_jump) - new_jump
1485	l.srli	r6,r6,6			// new offset shifted right 2
1486
1487	// r6 is new jump offset
1488	l.lwz	r4,(TRAMP_SLOT_2+0x0)(r3)	// load jump instruction
1489	l.srli	r4,r4,16
1490	l.andi	r4,r4,0xfc00		// get opcode part
1491	l.slli	r4,r4,16
1492	l.or	r6,r4,r6		// l.b(n)f new offset
1493	l.sw	TRAMP_SLOT_2(r3),r6	// write it back
1494
1495	/* we need to add l.j to EEA + 0x8 */
1496	tophys	(r4,r2)			// may not be needed (due to shifts down_
1497	l.addi	r4,r4,(0x8 - 0x8)	// jump target = r2 + 0x8 (compensate for 0x8)
1498					// jump position = r5 + 0x8 (0x8 compensated)
1499	l.sub	r4,r4,r5		// jump offset = target - new_position + 0x8
1500
1501	l.slli	r4,r4,4			// the amount of info in imediate of jump
1502	l.srli	r4,r4,6			// jump instruction with offset
1503	l.sw	TRAMP_SLOT_4(r3),r4	// write it to 4th slot
1504
1505	/* fallthrough */
1506
1507trampoline_out:
1508	// set up new EPC to point to our trampoline code
1509	LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
1510	l.mtspr	r0,r5,SPR_EPCR_BASE
1511
1512	// immu_trampoline is (4x) CACHE_LINE aligned
1513	// and only 6 instructions long,
1514	// so we need to invalidate only 2 lines
1515
1516	/* Establish cache block size
1517	   If BS=0, 16;
1518	   If BS=1, 32;
1519	   r14 contain block size
1520	*/
1521	l.mfspr r21,r0,SPR_ICCFGR
1522	l.andi	r21,r21,SPR_ICCFGR_CBS
1523	l.srli	r21,r21,7
1524	l.ori	r23,r0,16
1525	l.sll	r14,r23,r21
1526
1527	l.mtspr	r0,r5,SPR_ICBIR
1528	l.add	r5,r5,r14
1529	l.mtspr	r0,r5,SPR_ICBIR
1530
1531	l.jr	r9
1532	l.nop
1533
1534
1535/*
1536 * DSCR: prints a string referenced by r3.
1537 *
1538 * PRMS: r3     	- address of the first character of null
1539 *			terminated string to be printed
1540 *
1541 * PREQ: UART at UART_BASE_ADD has to be initialized
1542 *
1543 * POST: caller should be aware that r3, r9 are changed
1544 */
1545ENTRY(_emergency_print)
1546	EMERGENCY_PRINT_STORE_GPR4
1547	EMERGENCY_PRINT_STORE_GPR5
1548	EMERGENCY_PRINT_STORE_GPR6
1549	EMERGENCY_PRINT_STORE_GPR7
15502:
1551	l.lbz	r7,0(r3)
1552	l.sfeq	r7,r0
1553	l.bf	9f
1554	l.nop
1555
1556// putc:
1557	l.movhi r4,hi(UART_BASE_ADD)
1558
1559	l.addi  r6,r0,0x20
15601:      l.lbz   r5,5(r4)
1561	l.andi  r5,r5,0x20
1562	l.sfeq  r5,r6
1563	l.bnf   1b
1564	l.nop
1565
1566	l.sb    0(r4),r7
1567
1568	l.addi  r6,r0,0x60
15691:      l.lbz   r5,5(r4)
1570	l.andi  r5,r5,0x60
1571	l.sfeq  r5,r6
1572	l.bnf   1b
1573	l.nop
1574
1575	/* next character */
1576	l.j	2b
1577	l.addi	r3,r3,0x1
1578
15799:
1580	EMERGENCY_PRINT_LOAD_GPR7
1581	EMERGENCY_PRINT_LOAD_GPR6
1582	EMERGENCY_PRINT_LOAD_GPR5
1583	EMERGENCY_PRINT_LOAD_GPR4
1584	l.jr	r9
1585	l.nop
1586
1587ENTRY(_emergency_print_nr)
1588	EMERGENCY_PRINT_STORE_GPR4
1589	EMERGENCY_PRINT_STORE_GPR5
1590	EMERGENCY_PRINT_STORE_GPR6
1591	EMERGENCY_PRINT_STORE_GPR7
1592	EMERGENCY_PRINT_STORE_GPR8
1593
1594	l.addi	r8,r0,32		// shift register
1595
15961:	/* remove leading zeros */
1597	l.addi	r8,r8,-0x4
1598	l.srl	r7,r3,r8
1599	l.andi	r7,r7,0xf
1600
1601	/* don't skip the last zero if number == 0x0 */
1602	l.sfeqi	r8,0x4
1603	l.bf	2f
1604	l.nop
1605
1606	l.sfeq	r7,r0
1607	l.bf	1b
1608	l.nop
1609
16102:
1611	l.srl	r7,r3,r8
1612
1613	l.andi	r7,r7,0xf
1614	l.sflts	r8,r0
1615	l.bf	9f
1616
1617	l.sfgtui r7,0x9
1618	l.bnf	8f
1619	l.nop
1620	l.addi	r7,r7,0x27
1621
16228:
1623	l.addi	r7,r7,0x30
1624// putc:
1625	l.movhi r4,hi(UART_BASE_ADD)
1626
1627	l.addi  r6,r0,0x20
16281:      l.lbz   r5,5(r4)
1629	l.andi  r5,r5,0x20
1630	l.sfeq  r5,r6
1631	l.bnf   1b
1632	l.nop
1633
1634	l.sb    0(r4),r7
1635
1636	l.addi  r6,r0,0x60
16371:      l.lbz   r5,5(r4)
1638	l.andi  r5,r5,0x60
1639	l.sfeq  r5,r6
1640	l.bnf   1b
1641	l.nop
1642
1643	/* next character */
1644	l.j	2b
1645	l.addi	r8,r8,-0x4
1646
16479:
1648	EMERGENCY_PRINT_LOAD_GPR8
1649	EMERGENCY_PRINT_LOAD_GPR7
1650	EMERGENCY_PRINT_LOAD_GPR6
1651	EMERGENCY_PRINT_LOAD_GPR5
1652	EMERGENCY_PRINT_LOAD_GPR4
1653	l.jr	r9
1654	l.nop
1655
1656
1657/*
1658 * This should be used for debugging only.
1659 * It messes up the Linux early serial output
1660 * somehow, so use it sparingly and essentially
1661 * only if you need to debug something that goes wrong
1662 * before Linux gets the early serial going.
1663 *
1664 * Furthermore, you'll have to make sure you set the
1665 * UART_DEVISOR correctly according to the system
1666 * clock rate.
1667 *
1668 *
1669 */
1670
1671
1672
1673#define SYS_CLK            20000000
1674//#define SYS_CLK            1843200
1675#define OR32_CONSOLE_BAUD  115200
1676#define UART_DIVISOR       SYS_CLK/(16*OR32_CONSOLE_BAUD)
1677
1678ENTRY(_early_uart_init)
1679	l.movhi	r3,hi(UART_BASE_ADD)
1680
1681	l.addi	r4,r0,0x7
1682	l.sb	0x2(r3),r4
1683
1684	l.addi	r4,r0,0x0
1685	l.sb	0x1(r3),r4
1686
1687	l.addi	r4,r0,0x3
1688	l.sb	0x3(r3),r4
1689
1690	l.lbz	r5,3(r3)
1691	l.ori	r4,r5,0x80
1692	l.sb	0x3(r3),r4
1693	l.addi	r4,r0,((UART_DIVISOR>>8) & 0x000000ff)
1694	l.sb	UART_DLM(r3),r4
1695	l.addi  r4,r0,((UART_DIVISOR) & 0x000000ff)
1696	l.sb	UART_DLL(r3),r4
1697	l.sb	0x3(r3),r5
1698
1699	l.jr	r9
1700	l.nop
1701
1702	.align	0x1000
1703	.global _secondary_evbar
1704_secondary_evbar:
1705
1706	.space 0x800
1707	/* Just disable interrupts and Return */
1708	l.ori	r3,r0,SPR_SR_SM
1709	l.mtspr	r0,r3,SPR_ESR_BASE
1710	l.rfe
1711
1712
1713	.section .rodata
1714_string_unhandled_exception:
1715	.string "\n\rRunarunaround: Unhandled exception 0x\0"
1716
1717_string_epc_prefix:
1718	.string ": EPC=0x\0"
1719
1720_string_nl:
1721	.string "\n\r\0"
1722
1723
1724/* ========================================[ page aligned structures ]=== */
1725
1726/*
1727 * .data section should be page aligned
1728 *	(look into arch/or32/kernel/vmlinux.lds)
1729 */
1730	.section .data,"aw"
1731	.align	8192
1732	.global  empty_zero_page
1733empty_zero_page:
1734	.space  8192
1735
1736	.global  swapper_pg_dir
1737swapper_pg_dir:
1738	.space  8192
1739
1740	.global	_unhandled_stack
1741_unhandled_stack:
1742	.space	8192
1743_unhandled_stack_top:
1744
1745/* ============================================================[ EOF ]=== */