arch/arm/common/fiq_debugger.c

   1 /*
   2  * arch/arm/common/fiq_debugger.c
   3  *
   4  * Serial Debugger Interface accessed through an FIQ interrupt.
   5  *
   6  * Copyright (C) 2008 Google, Inc.
   7  *
   8  * This software is licensed under the terms of the GNU General Public
   9  * License version 2, as published by the Free Software Foundation, and
  10  * may be copied, distributed, and modified under those terms.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <stdarg.h>
  19 #include <linux/module.h>
  20 #include <linux/io.h>
  21 #include <linux/console.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/clk.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/kernel_stat.h>
  26 #include <linux/irq.h>
  27 #include <linux/delay.h>
  28 #include <linux/reboot.h>
  29 #include <linux/sched.h>
  30 #include <linux/slab.h>
  31 #include <linux/smp.h>
  32 #include <linux/timer.h>
  33 #include <linux/tty.h>
  34 #include <linux/tty_flip.h>
  35 #include <linux/wakelock.h>
  36
  37 #include <asm/fiq_debugger.h>
  38 #include <asm/fiq_glue.h>
  39 #include <asm/stacktrace.h>
  40
  41 #include <linux/uaccess.h>
  42
  43 #include "fiq_debugger_ringbuf.h"
  44
  45 #define DEBUG_MAX 64
  46 #define MAX_UNHANDLED_FIQ_COUNT 1000000
  47
  48 #define THREAD_INFO(sp) ((struct thread_info *) \
  49                 ((unsigned long)(sp) & ~(THREAD_SIZE - 1)))
  50
  51 struct fiq_debugger_state {
  52         struct fiq_glue_handler handler;
  53
  54         int fiq;
  55         int uart_irq;
  56         int signal_irq;
  57         int wakeup_irq;
  58         bool wakeup_irq_no_set_wake;
  59         struct clk *clk;
  60         struct fiq_debugger_pdata *pdata;
  61         struct platform_device *pdev;
  62
  63         char debug_cmd[DEBUG_MAX];
  64         int debug_busy;
  65         int debug_abort;
  66
  67         char debug_buf[DEBUG_MAX];
  68         int debug_count;
  69
  70         bool no_sleep;
  71         bool debug_enable;
  72         bool ignore_next_wakeup_irq;
  73         struct timer_list sleep_timer;
  74         spinlock_t sleep_timer_lock;
  75         bool uart_enabled;
  76         struct wake_lock debugger_wake_lock;
  77         bool console_enable;
  78         int current_cpu;
  79         atomic_t unhandled_fiq_count;
  80         bool in_fiq;
  81
  82 #ifdef CONFIG_FIQ_DEBUGGER_CONSOLE
  83         struct console console;
  84         struct tty_driver *tty_driver;
  85         struct tty_struct *tty;
  86         int tty_open_count;
  87         struct fiq_debugger_ringbuf *tty_rbuf;
  88         bool syslog_dumping;
  89 #endif
  90
  91         unsigned int last_irqs[NR_IRQS];
  92         unsigned int last_local_timer_irqs[NR_CPUS];
  93 };
  94
  95 #ifdef CONFIG_FIQ_DEBUGGER_NO_SLEEP
  96 static bool initial_no_sleep = true;
  97 #else
  98 static bool initial_no_sleep;
  99 #endif
 100
 101 #ifdef CONFIG_FIQ_DEBUGGER_CONSOLE_DEFAULT_ENABLE
 102 static bool initial_debug_enable = true;
 103 static bool initial_console_enable = true;
 104 #else
 105 static bool initial_debug_enable;
 106 static bool initial_console_enable;
 107 #endif
 108
 109 module_param_named(no_sleep, initial_no_sleep, bool, 0644);
 110 module_param_named(debug_enable, initial_debug_enable, bool, 0644);
 111 module_param_named(console_enable, initial_console_enable, bool, 0644);
 112
 113 #ifdef CONFIG_FIQ_DEBUGGER_WAKEUP_IRQ_ALWAYS_ON
 114 static inline void enable_wakeup_irq(struct fiq_debugger_state *state) {}
 115 static inline void disable_wakeup_irq(struct fiq_debugger_state *state) {}
 116 #else
 117 static inline void enable_wakeup_irq(struct fiq_debugger_state *state)
 118 {
 119         if (state->wakeup_irq < 0)
 120                 return;
 121         enable_irq(state->wakeup_irq);
 122         if (!state->wakeup_irq_no_set_wake)
 123                 enable_irq_wake(state->wakeup_irq);
 124 }
 125 static inline void disable_wakeup_irq(struct fiq_debugger_state *state)
 126 {
 127         if (state->wakeup_irq < 0)
 128                 return;
 129         disable_irq_nosync(state->wakeup_irq);
 130         if (!state->wakeup_irq_no_set_wake)
 131                 disable_irq_wake(state->wakeup_irq);
 132 }
 133 #endif
 134
 135 static bool inline debug_have_fiq(struct fiq_debugger_state *state)
 136 {
 137         return (state->fiq >= 0);
 138 }
 139
 140 static void debug_force_irq(struct fiq_debugger_state *state)
 141 {
 142         unsigned int irq = state->signal_irq;
 143
 144         if (WARN_ON(!debug_have_fiq(state)))
 145                 return;
 146         if (state->pdata->force_irq) {
 147                 state->pdata->force_irq(state->pdev, irq);
 148         } else {
 149                 struct irq_chip *chip = irq_get_chip(irq);
 150                 if (chip && chip->irq_retrigger)
 151                         chip->irq_retrigger(irq_get_irq_data(irq));
 152         }
 153 }
 154
 155 static void debug_uart_enable(struct fiq_debugger_state *state)
 156 {
 157         if (state->clk)
 158                 clk_enable(state->clk);
 159         if (state->pdata->uart_enable)
 160                 state->pdata->uart_enable(state->pdev);
 161 }
 162
 163 static void debug_uart_disable(struct fiq_debugger_state *state)
 164 {
 165         if (state->pdata->uart_disable)
 166                 state->pdata->uart_disable(state->pdev);
 167         if (state->clk)
 168                 clk_disable(state->clk);
 169 }
 170
 171 static void debug_uart_flush(struct fiq_debugger_state *state)
 172 {
 173         if (state->pdata->uart_flush)
 174                 state->pdata->uart_flush(state->pdev);
 175 }
 176
 177 static void debug_puts(struct fiq_debugger_state *state, char *s)
 178 {
 179         unsigned c;
 180         while ((c = *s++)) {
 181                 if (c == '\n')
 182                         state->pdata->uart_putc(state->pdev, '\r');
 183                 state->pdata->uart_putc(state->pdev, c);
 184         }
 185 }
 186
 187 static void debug_prompt(struct fiq_debugger_state *state)
 188 {
 189         debug_puts(state, "debug> ");
 190 }
 191
 192 int log_buf_copy(char *dest, int idx, int len);
 193 static void dump_kernel_log(struct fiq_debugger_state *state)
 194 {
 195         char buf[1024];
 196         int idx = 0;
 197         int ret;
 198         int saved_oip;
 199
 200         /* setting oops_in_progress prevents log_buf_copy()
 201          * from trying to take a spinlock which will make it
 202          * very unhappy in some cases...
 203          */
 204         saved_oip = oops_in_progress;
 205         oops_in_progress = 1;
 206         for (;;) {
 207                 ret = log_buf_copy(buf, idx, 1023);
 208                 if (ret <= 0)
 209                         break;
 210                 buf[ret] = 0;
 211                 debug_puts(state, buf);
 212                 idx += ret;
 213         }
 214         oops_in_progress = saved_oip;
 215 }
 216
 217 static char *mode_name(unsigned cpsr)
 218 {
 219         switch (cpsr & MODE_MASK) {
 220         case USR_MODE: return "USR";
 221         case FIQ_MODE: return "FIQ";
 222         case IRQ_MODE: return "IRQ";
 223         case SVC_MODE: return "SVC";
 224         case ABT_MODE: return "ABT";
 225         case UND_MODE: return "UND";
 226         case SYSTEM_MODE: return "SYS";
 227         default: return "???";
 228         }
 229 }
 230
 231 static int debug_printf(void *cookie, const char *fmt, ...)
 232 {
 233         struct fiq_debugger_state *state = cookie;
 234         char buf[256];
 235         va_list ap;
 236
 237         va_start(ap, fmt);
 238         vsnprintf(buf, sizeof(buf), fmt, ap);
 239         va_end(ap);
 240
 241         debug_puts(state, buf);
 242         return state->debug_abort;
 243 }
 244
 245 /* Safe outside fiq context */
 246 static int debug_printf_nfiq(void *cookie, const char *fmt, ...)
 247 {
 248         struct fiq_debugger_state *state = cookie;
 249         char buf[256];
 250         va_list ap;
 251         unsigned long irq_flags;
 252
 253         va_start(ap, fmt);
 254         vsnprintf(buf, 128, fmt, ap);
 255         va_end(ap);
 256
 257         local_irq_save(irq_flags);
 258         debug_puts(state, buf);
 259         debug_uart_flush(state);
 260         local_irq_restore(irq_flags);
 261         return state->debug_abort;
 262 }
 263
 264 static void dump_regs(struct fiq_debugger_state *state, unsigned *regs)
 265 {
 266         debug_printf(state, " r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",
 267                         regs[0], regs[1], regs[2], regs[3]);
 268         debug_printf(state, " r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",
 269                         regs[4], regs[5], regs[6], regs[7]);
 270         debug_printf(state, " r8 %08x  r9 %08x r10 %08x r11 %08x  mode %s\n",
 271                         regs[8], regs[9], regs[10], regs[11],
 272                         mode_name(regs[16]));
 273         if ((regs[16] & MODE_MASK) == USR_MODE)
 274                 debug_printf(state, " ip %08x  sp %08x  lr %08x  pc %08x  "
 275                                 "cpsr %08x\n", regs[12], regs[13], regs[14],
 276                                 regs[15], regs[16]);
 277         else
 278                 debug_printf(state, " ip %08x  sp %08x  lr %08x  pc %08x  "
 279                                 "cpsr %08x  spsr %08x\n", regs[12], regs[13],
 280                                 regs[14], regs[15], regs[16], regs[17]);
 281 }
 282
 283 struct mode_regs {
 284         unsigned long sp_svc;
 285         unsigned long lr_svc;
 286         unsigned long spsr_svc;
 287
 288         unsigned long sp_abt;
 289         unsigned long lr_abt;
 290         unsigned long spsr_abt;
 291
 292         unsigned long sp_und;
 293         unsigned long lr_und;
 294         unsigned long spsr_und;
 295
 296         unsigned long sp_irq;
 297         unsigned long lr_irq;
 298         unsigned long spsr_irq;
 299
 300         unsigned long r8_fiq;
 301         unsigned long r9_fiq;
 302         unsigned long r10_fiq;
 303         unsigned long r11_fiq;
 304         unsigned long r12_fiq;
 305         unsigned long sp_fiq;
 306         unsigned long lr_fiq;
 307         unsigned long spsr_fiq;
 308 };
 309
 310 void __naked get_mode_regs(struct mode_regs *regs)
 311 {
 312         asm volatile (
 313         "mrs    r1, cpsr\n"
 314         "msr    cpsr_c, #0xd3 @(SVC_MODE | PSR_I_BIT | PSR_F_BIT)\n"
 315         "stmia  r0!, {r13 - r14}\n"
 316         "mrs    r2, spsr\n"
 317         "msr    cpsr_c, #0xd7 @(ABT_MODE | PSR_I_BIT | PSR_F_BIT)\n"
 318         "stmia  r0!, {r2, r13 - r14}\n"
 319         "mrs    r2, spsr\n"
 320         "msr    cpsr_c, #0xdb @(UND_MODE | PSR_I_BIT | PSR_F_BIT)\n"
 321         "stmia  r0!, {r2, r13 - r14}\n"
 322         "mrs    r2, spsr\n"
 323         "msr    cpsr_c, #0xd2 @(IRQ_MODE | PSR_I_BIT | PSR_F_BIT)\n"
 324         "stmia  r0!, {r2, r13 - r14}\n"
 325         "mrs    r2, spsr\n"
 326         "msr    cpsr_c, #0xd1 @(FIQ_MODE | PSR_I_BIT | PSR_F_BIT)\n"
 327         "stmia  r0!, {r2, r8 - r14}\n"
 328         "mrs    r2, spsr\n"
 329         "stmia  r0!, {r2}\n"
 330         "msr    cpsr_c, r1\n"
 331         "bx     lr\n");
 332 }
 333
 334
 335 static void dump_allregs(struct fiq_debugger_state *state, unsigned *regs)
 336 {
 337         struct mode_regs mode_regs;
 338         dump_regs(state, regs);
 339         get_mode_regs(&mode_regs);
 340         debug_printf(state, " svc: sp %08x  lr %08x  spsr %08x\n",
 341                         mode_regs.sp_svc, mode_regs.lr_svc, mode_regs.spsr_svc);
 342         debug_printf(state, " abt: sp %08x  lr %08x  spsr %08x\n",
 343                         mode_regs.sp_abt, mode_regs.lr_abt, mode_regs.spsr_abt);
 344         debug_printf(state, " und: sp %08x  lr %08x  spsr %08x\n",
 345                         mode_regs.sp_und, mode_regs.lr_und, mode_regs.spsr_und);
 346         debug_printf(state, " irq: sp %08x  lr %08x  spsr %08x\n",
 347                         mode_regs.sp_irq, mode_regs.lr_irq, mode_regs.spsr_irq);
 348         debug_printf(state, " fiq: r8 %08x  r9 %08x  r10 %08x  r11 %08x  "
 349                         "r12 %08x\n",
 350                         mode_regs.r8_fiq, mode_regs.r9_fiq, mode_regs.r10_fiq,
 351                         mode_regs.r11_fiq, mode_regs.r12_fiq);
 352         debug_printf(state, " fiq: sp %08x  lr %08x  spsr %08x\n",
 353                         mode_regs.sp_fiq, mode_regs.lr_fiq, mode_regs.spsr_fiq);
 354 }
 355
 356 static void dump_irqs(struct fiq_debugger_state *state)
 357 {
 358         int n;
 359
 360         debug_printf(state, "irqnr       total  since-last   status  name\n");
 361         for (n = 0; n < NR_IRQS; n++) {
 362                 struct irqaction *act = irq_desc[n].action;
 363                 if (!act && !kstat_irqs(n))
 364                         continue;
 365                 debug_printf(state, "%5d: %10u %11u %8x  %s\n", n,
 366                         kstat_irqs(n),
 367                         kstat_irqs(n) - state->last_irqs[n],
 368                         irq_desc[n].status_use_accessors,
 369                         (act && act->name) ? act->name : "???");
 370                 state->last_irqs[n] = kstat_irqs(n);
 371         }
 372 }
 373
 374 struct stacktrace_state {
 375         struct fiq_debugger_state *state;
 376         unsigned int depth;
 377 };
 378
 379 static int report_trace(struct stackframe *frame, void *d)
 380 {
 381         struct stacktrace_state *sts = d;
 382
 383         if (sts->depth) {
 384                 debug_printf(sts->state,
 385                         "  pc: %p (%pF), lr %p (%pF), sp %p, fp %p\n",
 386                         frame->pc, frame->pc, frame->lr, frame->lr,
 387                         frame->sp, frame->fp);
 388                 sts->depth--;
 389                 return 0;
 390         }
 391         debug_printf(sts->state, "  ...\n");
 392
 393         return sts->depth == 0;
 394 }
 395
 396 struct frame_tail {
 397         struct frame_tail *fp;
 398         unsigned long sp;
 399         unsigned long lr;
 400 } __attribute__((packed));
 401
 402 static struct frame_tail *user_backtrace(struct fiq_debugger_state *state,
 403                                         struct frame_tail *tail)
 404 {
 405         struct frame_tail buftail[2];
 406
 407         /* Also check accessibility of one struct frame_tail beyond */
 408         if (!access_ok(VERIFY_READ, tail, sizeof(buftail))) {
 409                 debug_printf(state, "  invalid frame pointer %p\n", tail);
 410                 return NULL;
 411         }
 412         if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail))) {
 413                 debug_printf(state,
 414                         "  failed to copy frame pointer %p\n", tail);
 415                 return NULL;
 416         }
 417
 418         debug_printf(state, "  %p\n", buftail[0].lr);
 419
 420         /* frame pointers should strictly progress back up the stack
 421          * (towards higher addresses) */
 422         if (tail >= buftail[0].fp)
 423                 return NULL;
 424
 425         return buftail[0].fp-1;
 426 }
 427
 428 void dump_stacktrace(struct fiq_debugger_state *state,
 429                 struct pt_regs * const regs, unsigned int depth, void *ssp)
 430 {
 431         struct frame_tail *tail;
 432         struct thread_info *real_thread_info = THREAD_INFO(ssp);
 433         struct stacktrace_state sts;
 434
 435         sts.depth = depth;
 436         sts.state = state;
 437         *current_thread_info() = *real_thread_info;
 438
 439         if (!current)
 440                 debug_printf(state, "current NULL\n");
 441         else
 442                 debug_printf(state, "pid: %d  comm: %s\n",
 443                         current->pid, current->comm);
 444         dump_regs(state, (unsigned *)regs);
 445
 446         if (!user_mode(regs)) {
 447                 struct stackframe frame;
 448                 frame.fp = regs->ARM_fp;
 449                 frame.sp = regs->ARM_sp;
 450                 frame.lr = regs->ARM_lr;
 451                 frame.pc = regs->ARM_pc;
 452                 debug_printf(state,
 453                         "  pc: %p (%pF), lr %p (%pF), sp %p, fp %p\n",
 454                         regs->ARM_pc, regs->ARM_pc, regs->ARM_lr, regs->ARM_lr,
 455                         regs->ARM_sp, regs->ARM_fp);
 456                 walk_stackframe(&frame, report_trace, &sts);
 457                 return;
 458         }
 459
 460         tail = ((struct frame_tail *) regs->ARM_fp) - 1;
 461         while (depth-- && tail && !((unsigned long) tail & 3))
 462                 tail = user_backtrace(state, tail);
 463 }
 464
 465 static void do_ps(struct fiq_debugger_state *state)
 466 {
 467         struct task_struct *g;
 468         struct task_struct *p;
 469         unsigned task_state;
 470         static const char stat_nam[] = "RSDTtZX";
 471
 472         debug_printf(state, "pid   ppid  prio task            pc\n");
 473         read_lock(&tasklist_lock);
 474         do_each_thread(g, p) {
 475                 task_state = p->state ? __ffs(p->state) + 1 : 0;
 476                 debug_printf(state,
 477                              "%5d %5d %4d ", p->pid, p->parent->pid, p->prio);
 478                 debug_printf(state, "%-13.13s %c", p->comm,
 479                              task_state >= sizeof(stat_nam) ? '?' : stat_nam[task_state]);
 480                 if (task_state == TASK_RUNNING)
 481                         debug_printf(state, " running\n");
 482                 else
 483                         debug_printf(state, " %08lx\n", thread_saved_pc(p));
 484         } while_each_thread(g, p);
 485         read_unlock(&tasklist_lock);
 486 }
 487
 488 #ifdef CONFIG_FIQ_DEBUGGER_CONSOLE
 489 static void begin_syslog_dump(struct fiq_debugger_state *state)
 490 {
 491         state->syslog_dumping = true;
 492 }
 493
 494 static void end_syslog_dump(struct fiq_debugger_state *state)
 495 {
 496         state->syslog_dumping = false;
 497 }
 498 #else
 499 extern int do_syslog(int type, char __user *bug, int count);
 500 static void begin_syslog_dump(struct fiq_debugger_state *state)
 501 {
 502         do_syslog(5 /* clear */, NULL, 0);
 503 }
 504
 505 static void end_syslog_dump(struct fiq_debugger_state *state)
 506 {
 507         char buf[128];
 508         int ret;
 509         int idx = 0;
 510
 511         while (1) {
 512                 ret = log_buf_copy(buf, idx, sizeof(buf) - 1);
 513                 if (ret <= 0)
 514                         break;
 515                 buf[ret] = 0;
 516                 debug_printf(state, "%s", buf);
 517                 idx += ret;
 518         }
 519 }
 520 #endif
 521
 522 static void do_sysrq(struct fiq_debugger_state *state, char rq)
 523 {
 524         begin_syslog_dump(state);
 525         handle_sysrq(rq);
 526         end_syslog_dump(state);
 527 }
 528
 529 /* This function CANNOT be called in FIQ context */
 530 static void debug_irq_exec(struct fiq_debugger_state *state, char *cmd)
 531 {
 532         if (!strcmp(cmd, "ps"))
 533                 do_ps(state);
 534         if (!strcmp(cmd, "sysrq"))
 535                 do_sysrq(state, 'h');
 536         if (!strncmp(cmd, "sysrq ", 6))
 537                 do_sysrq(state, cmd[6]);
 538 }
 539
 540 static void debug_help(struct fiq_debugger_state *state)
 541 {
 542         debug_printf(state,     "FIQ Debugger commands:\n"
 543                                 " pc            PC status\n"
 544                                 " regs          Register dump\n"
 545                                 " allregs       Extended Register dump\n"
 546                                 " bt            Stack trace\n"
 547                                 " reboot        Reboot\n"
 548                                 " irqs          Interupt status\n"
 549                                 " kmsg          Kernel log\n"
 550                                 " version       Kernel version\n");
 551         debug_printf(state,     " sleep         Allow sleep while in FIQ\n"
 552                                 " nosleep       Disable sleep while in FIQ\n"
 553                                 " console       Switch terminal to console\n"
 554                                 " cpu           Current CPU\n"
 555                                 " cpu <number>  Switch to CPU<number>\n");
 556         debug_printf(state,     " ps            Process list\n"
 557                                 " sysrq         sysrq options\n"
 558                                 " sysrq <param> Execute sysrq with <param>\n");
 559 }
 560
 561 static void take_affinity(void *info)
 562 {
 563         struct fiq_debugger_state *state = info;
 564         struct cpumask cpumask;
 565
 566         cpumask_clear(&cpumask);
 567         cpumask_set_cpu(get_cpu(), &cpumask);
 568
 569         irq_set_affinity(state->uart_irq, &cpumask);
 570 }
 571
 572 static void switch_cpu(struct fiq_debugger_state *state, int cpu)
 573 {
 574         if (!debug_have_fiq(state))
 575                 smp_call_function_single(cpu, take_affinity, state, false);
 576         state->current_cpu = cpu;
 577 }
 578
 579 static bool debug_fiq_exec(struct fiq_debugger_state *state,
 580                         const char *cmd, unsigned *regs, void *svc_sp)
 581 {
 582         bool signal_helper = false;
 583
 584         if (!strcmp(cmd, "help") || !strcmp(cmd, "?")) {
 585                 debug_help(state);
 586         } else if (!strcmp(cmd, "pc")) {
 587                 debug_printf(state, " pc %08x cpsr %08x mode %s\n",
 588                         regs[15], regs[16], mode_name(regs[16]));
 589         } else if (!strcmp(cmd, "regs")) {
 590                 dump_regs(state, regs);
 591         } else if (!strcmp(cmd, "allregs")) {
 592                 dump_allregs(state, regs);
 593         } else if (!strcmp(cmd, "bt")) {
 594                 dump_stacktrace(state, (struct pt_regs *)regs, 100, svc_sp);
 595         } else if (!strncmp(cmd, "reboot", 6)) {
 596                 cmd += 6;
 597                 while (*cmd == ' ')
 598                         cmd++;
 599                 if (*cmd) {
 600                         char tmp_cmd[32];
 601                         strlcpy(tmp_cmd, cmd, sizeof(tmp_cmd));
 602                         kernel_restart(tmp_cmd);
 603                 } else {
 604                         kernel_restart(NULL);
 605                 }
 606         } else if (!strcmp(cmd, "irqs")) {
 607                 dump_irqs(state);
 608         } else if (!strcmp(cmd, "kmsg")) {
 609                 dump_kernel_log(state);
 610         } else if (!strcmp(cmd, "version")) {
 611                 debug_printf(state, "%s\n", linux_banner);
 612         } else if (!strcmp(cmd, "sleep")) {
 613                 state->no_sleep = false;
 614                 debug_printf(state, "enabling sleep\n");
 615         } else if (!strcmp(cmd, "nosleep")) {
 616                 state->no_sleep = true;
 617                 debug_printf(state, "disabling sleep\n");
 618         } else if (!strcmp(cmd, "console")) {
 619                 state->console_enable = true;
 620                 debug_printf(state, "console mode\n");
 621         } else if (!strcmp(cmd, "cpu")) {
 622                 debug_printf(state, "cpu %d\n", state->current_cpu);
 623         } else if (!strncmp(cmd, "cpu ", 4)) {
 624                 unsigned long cpu = 0;
 625                 if (strict_strtoul(cmd + 4, 10, &cpu) == 0)
 626                         switch_cpu(state, cpu);
 627                 else
 628                         debug_printf(state, "invalid cpu\n");
 629                 debug_printf(state, "cpu %d\n", state->current_cpu);
 630         } else {
 631                 if (state->debug_busy) {
 632                         debug_printf(state,
 633                                 "command processor busy. trying to abort.\n");
 634                         state->debug_abort = -1;
 635                 } else {
 636                         strcpy(state->debug_cmd, cmd);
 637                         state->debug_busy = 1;
 638                 }
 639
 640                 return true;
 641         }
 642         if (!state->console_enable)
 643                 debug_prompt(state);
 644
 645         return signal_helper;
 646 }
 647
 648 static void sleep_timer_expired(unsigned long data)
 649 {
 650         struct fiq_debugger_state *state = (struct fiq_debugger_state *)data;
 651         unsigned long flags;
 652
 653         spin_lock_irqsave(&state->sleep_timer_lock, flags);
 654         if (state->uart_enabled && !state->no_sleep) {
 655                 if (state->debug_enable && !state->console_enable) {
 656                         state->debug_enable = false;
 657                         debug_printf_nfiq(state, "suspending fiq debugger\n");
 658                 }
 659                 state->ignore_next_wakeup_irq = true;
 660                 debug_uart_disable(state);
 661                 state->uart_enabled = false;
 662                 enable_wakeup_irq(state);
 663         }
 664         wake_unlock(&state->debugger_wake_lock);
 665         spin_unlock_irqrestore(&state->sleep_timer_lock, flags);
 666 }
 667
 668 static void handle_wakeup(struct fiq_debugger_state *state)
 669 {
 670         unsigned long flags;
 671
 672         spin_lock_irqsave(&state->sleep_timer_lock, flags);
 673         if (state->wakeup_irq >= 0 && state->ignore_next_wakeup_irq) {
 674                 state->ignore_next_wakeup_irq = false;
 675         } else if (!state->uart_enabled) {
 676                 wake_lock(&state->debugger_wake_lock);
 677                 debug_uart_enable(state);
 678                 state->uart_enabled = true;
 679                 disable_wakeup_irq(state);
 680                 mod_timer(&state->sleep_timer, jiffies + HZ / 2);
 681         }
 682         spin_unlock_irqrestore(&state->sleep_timer_lock, flags);
 683 }
 684
 685 static irqreturn_t wakeup_irq_handler(int irq, void *dev)
 686 {
 687         struct fiq_debugger_state *state = dev;
 688
 689         if (!state->no_sleep)
 690                 debug_puts(state, "WAKEUP\n");
 691         handle_wakeup(state);
 692
 693         return IRQ_HANDLED;
 694 }
 695
 696
 697 static void debug_handle_irq_context(struct fiq_debugger_state *state)
 698 {
 699         if (!state->no_sleep) {
 700                 unsigned long flags;
 701
 702                 spin_lock_irqsave(&state->sleep_timer_lock, flags);
 703                 wake_lock(&state->debugger_wake_lock);
 704                 mod_timer(&state->sleep_timer, jiffies + HZ * 5);
 705                 spin_unlock_irqrestore(&state->sleep_timer_lock, flags);
 706         }
 707 #if defined(CONFIG_FIQ_DEBUGGER_CONSOLE)
 708         if (state->tty) {
 709                 int i;
 710                 int count = fiq_debugger_ringbuf_level(state->tty_rbuf);
 711                 for (i = 0; i < count; i++) {
 712                         int c = fiq_debugger_ringbuf_peek(state->tty_rbuf, 0);
 713                         tty_insert_flip_char(state->tty, c, TTY_NORMAL);
 714                         if (!fiq_debugger_ringbuf_consume(state->tty_rbuf, 1))
 715                                 pr_warn("fiq tty failed to consume byte\n");
 716                 }
 717                 tty_flip_buffer_push(state->tty);
 718         }
 719 #endif
 720         if (state->debug_busy) {
 721                 debug_irq_exec(state, state->debug_cmd);
 722                 debug_prompt(state);
 723                 state->debug_busy = 0;
 724         }
 725 }
 726
 727 static int debug_getc(struct fiq_debugger_state *state)
 728 {
 729         return state->pdata->uart_getc(state->pdev);
 730 }
 731
 732 static bool debug_handle_uart_interrupt(struct fiq_debugger_state *state,
 733                         int this_cpu, void *regs, void *svc_sp)
 734 {
 735         int c;
 736         static int last_c;
 737         int count = 0;
 738         bool signal_helper = false;
 739
 740         if (this_cpu != state->current_cpu) {
 741                 if (state->in_fiq)
 742                         return false;
 743
 744                 if (atomic_inc_return(&state->unhandled_fiq_count) !=
 745                                         MAX_UNHANDLED_FIQ_COUNT)
 746                         return false;
 747
 748                 debug_printf(state, "fiq_debugger: cpu %d not responding, "
 749                         "reverting to cpu %d\n", state->current_cpu,
 750                         this_cpu);
 751
 752                 atomic_set(&state->unhandled_fiq_count, 0);
 753                 switch_cpu(state, this_cpu);
 754                 return false;
 755         }
 756
 757         state->in_fiq = true;
 758
 759         while ((c = debug_getc(state)) != FIQ_DEBUGGER_NO_CHAR) {
 760                 count++;
 761                 if (!state->debug_enable) {
 762                         if ((c == 13) || (c == 10)) {
 763                                 state->debug_enable = true;
 764                                 state->debug_count = 0;
 765                                 debug_prompt(state);
 766                         }
 767                 } else if (c == FIQ_DEBUGGER_BREAK) {
 768                         state->console_enable = false;
 769                         debug_puts(state, "fiq debugger mode\n");
 770                         state->debug_count = 0;
 771                         debug_prompt(state);
 772 #ifdef CONFIG_FIQ_DEBUGGER_CONSOLE
 773                 } else if (state->console_enable && state->tty_rbuf) {
 774                         fiq_debugger_ringbuf_push(state->tty_rbuf, c);
 775                         signal_helper = true;
 776 #endif
 777                 } else if ((c >= ' ') && (c < 127)) {
 778                         if (state->debug_count < (DEBUG_MAX - 1)) {
 779                                 state->debug_buf[state->debug_count++] = c;
 780                                 state->pdata->uart_putc(state->pdev, c);
 781                         }
 782                 } else if ((c == 8) || (c == 127)) {
 783                         if (state->debug_count > 0) {
 784                                 state->debug_count--;
 785                                 state->pdata->uart_putc(state->pdev, 8);
 786                                 state->pdata->uart_putc(state->pdev, ' ');
 787                                 state->pdata->uart_putc(state->pdev, 8);
 788                         }
 789                 } else if ((c == 13) || (c == 10)) {
 790                         if (c == '\r' || (c == '\n' && last_c != '\r')) {
 791                                 state->pdata->uart_putc(state->pdev, '\r');
 792                                 state->pdata->uart_putc(state->pdev, '\n');
 793                         }
 794                         if (state->debug_count) {
 795                                 state->debug_buf[state->debug_count] = 0;
 796                                 state->debug_count = 0;
 797                                 signal_helper |=
 798                                         debug_fiq_exec(state, state->debug_buf,
 799                                                        regs, svc_sp);
 800                         } else {
 801                                 debug_prompt(state);
 802                         }
 803                 }
 804                 last_c = c;
 805         }
 806         debug_uart_flush(state);
 807         if (state->pdata->fiq_ack)
 808                 state->pdata->fiq_ack(state->pdev, state->fiq);
 809
 810         /* poke sleep timer if necessary */
 811         if (state->debug_enable && !state->no_sleep)
 812                 signal_helper = true;
 813
 814         atomic_set(&state->unhandled_fiq_count, 0);
 815         state->in_fiq = false;
 816
 817         return signal_helper;
 818 }
 819
 820 static void debug_fiq(struct fiq_glue_handler *h, void *regs, void *svc_sp)
 821 {
 822         struct fiq_debugger_state *state =
 823                 container_of(h, struct fiq_debugger_state, handler);
 824         unsigned int this_cpu = THREAD_INFO(svc_sp)->cpu;
 825         bool need_irq;
 826
 827         need_irq = debug_handle_uart_interrupt(state, this_cpu, regs, svc_sp);
 828         if (need_irq)
 829                 debug_force_irq(state);
 830 }
 831
 832 /*
 833  * When not using FIQs, we only use this single interrupt as an entry point.
 834  * This just effectively takes over the UART interrupt and does all the work
 835  * in this context.
 836  */
 837 static irqreturn_t debug_uart_irq(int irq, void *dev)
 838 {
 839         struct fiq_debugger_state *state = dev;
 840         bool not_done;
 841
 842         handle_wakeup(state);
 843
 844         /* handle the debugger irq in regular context */
 845         not_done = debug_handle_uart_interrupt(state, smp_processor_id(),
 846                                               get_irq_regs(),
 847                                               current_thread_info());
 848         if (not_done)
 849                 debug_handle_irq_context(state);
 850
 851         return IRQ_HANDLED;
 852 }
 853
 854 /*
 855  * If FIQs are used, not everything can happen in fiq context.
 856  * FIQ handler does what it can and then signals this interrupt to finish the
 857  * job in irq context.
 858  */
 859 static irqreturn_t debug_signal_irq(int irq, void *dev)
 860 {
 861         struct fiq_debugger_state *state = dev;
 862
 863         if (state->pdata->force_irq_ack)
 864                 state->pdata->force_irq_ack(state->pdev, state->signal_irq);
 865
 866         debug_handle_irq_context(state);
 867
 868         return IRQ_HANDLED;
 869 }
 870
 871 static void debug_resume(struct fiq_glue_handler *h)
 872 {
 873         struct fiq_debugger_state *state =
 874                 container_of(h, struct fiq_debugger_state, handler);
 875         if (state->pdata->uart_resume)
 876                 state->pdata->uart_resume(state->pdev);
 877 }
 878
 879 #if defined(CONFIG_FIQ_DEBUGGER_CONSOLE)
 880 struct tty_driver *debug_console_device(struct console *co, int *index)
 881 {
 882         struct fiq_debugger_state *state;
 883         state = container_of(co, struct fiq_debugger_state, console);
 884         *index = 0;
 885         return state->tty_driver;
 886 }
 887
 888 static void debug_console_write(struct console *co,
 889                                 const char *s, unsigned int count)
 890 {
 891         struct fiq_debugger_state *state;
 892
 893         state = container_of(co, struct fiq_debugger_state, console);
 894
 895         if (!state->console_enable && !state->syslog_dumping)
 896                 return;
 897
 898         debug_uart_enable(state);
 899         while (count--) {
 900                 if (*s == '\n')
 901                         state->pdata->uart_putc(state->pdev, '\r');
 902                 state->pdata->uart_putc(state->pdev, *s++);
 903         }
 904         debug_uart_flush(state);
 905         debug_uart_disable(state);
 906 }
 907
 908 static struct console fiq_debugger_console = {
 909         .name = "ttyFIQ",
 910         .device = debug_console_device,
 911         .write = debug_console_write,
 912         .flags = CON_PRINTBUFFER | CON_ANYTIME | CON_ENABLED,
 913 };
 914
 915 int fiq_tty_open(struct tty_struct *tty, struct file *filp)
 916 {
 917         struct fiq_debugger_state *state = tty->driver->driver_state;
 918         if (state->tty_open_count++)
 919                 return 0;
 920
 921         tty->driver_data = state;
 922         state->tty = tty;
 923         return 0;
 924 }
 925
 926 void fiq_tty_close(struct tty_struct *tty, struct file *filp)
 927 {
 928         struct fiq_debugger_state *state = tty->driver_data;
 929         if (--state->tty_open_count)
 930                 return;
 931         state->tty = NULL;
 932 }
 933
 934 int  fiq_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
 935 {
 936         int i;
 937         struct fiq_debugger_state *state = tty->driver_data;
 938
 939         if (!state->console_enable)
 940                 return count;
 941
 942         debug_uart_enable(state);
 943         for (i = 0; i < count; i++)
 944                 state->pdata->uart_putc(state->pdev, *buf++);
 945         debug_uart_disable(state);
 946
 947         return count;
 948 }
 949
 950 int  fiq_tty_write_room(struct tty_struct *tty)
 951 {
 952         return 1024;
 953 }
 954
 955 static const struct tty_operations fiq_tty_driver_ops = {
 956         .write = fiq_tty_write,
 957         .write_room = fiq_tty_write_room,
 958         .open = fiq_tty_open,
 959         .close = fiq_tty_close,
 960 };
 961
 962 static int fiq_debugger_tty_init(struct fiq_debugger_state *state)
 963 {
 964         int ret = -EINVAL;
 965
 966         state->tty_driver = alloc_tty_driver(1);
 967         if (!state->tty_driver) {
 968                 pr_err("Failed to allocate fiq debugger tty\n");
 969                 return -ENOMEM;
 970         }
 971
 972         state->tty_driver->owner                = THIS_MODULE;
 973         state->tty_driver->driver_name  = "fiq-debugger";
 974         state->tty_driver->name         = "ttyFIQ";
 975         state->tty_driver->type         = TTY_DRIVER_TYPE_SERIAL;
 976         state->tty_driver->subtype      = SERIAL_TYPE_NORMAL;
 977         state->tty_driver->init_termios = tty_std_termios;
 978         state->tty_driver->init_termios.c_cflag =
 979                                         B115200 | CS8 | CREAD | HUPCL | CLOCAL;
 980         state->tty_driver->init_termios.c_ispeed =
 981                 state->tty_driver->init_termios.c_ospeed = 115200;
 982         state->tty_driver->flags                = TTY_DRIVER_REAL_RAW;
 983         tty_set_operations(state->tty_driver, &fiq_tty_driver_ops);
 984         state->tty_driver->driver_state = state;
 985
 986         ret = tty_register_driver(state->tty_driver);
 987         if (ret) {
 988                 pr_err("Failed to register fiq tty: %d\n", ret);
 989                 goto err;
 990         }
 991
 992         state->tty_rbuf = fiq_debugger_ringbuf_alloc(1024);
 993         if (!state->tty_rbuf) {
 994                 pr_err("Failed to allocate fiq debugger ringbuf\n");
 995                 ret = -ENOMEM;
 996                 goto err;
 997         }
 998
 999         pr_info("Registered FIQ tty driver %p\n", state->tty_driver);
1000         return 0;
1001
1002 err:
1003         fiq_debugger_ringbuf_free(state->tty_rbuf);
1004         state->tty_rbuf = NULL;
1005         put_tty_driver(state->tty_driver);
1006         return ret;
1007 }
1008 #endif
1009
1010 static int fiq_debugger_dev_suspend(struct device *dev)
1011 {
1012         struct platform_device *pdev = to_platform_device(dev);
1013         struct fiq_debugger_state *state = platform_get_drvdata(pdev);
1014
1015         if (state->pdata->uart_dev_suspend)
1016                 return state->pdata->uart_dev_suspend(pdev);
1017         return 0;
1018 }
1019
1020 static int fiq_debugger_dev_resume(struct device *dev)
1021 {
1022         struct platform_device *pdev = to_platform_device(dev);
1023         struct fiq_debugger_state *state = platform_get_drvdata(pdev);
1024
1025         if (state->pdata->uart_dev_resume)
1026                 return state->pdata->uart_dev_resume(pdev);
1027         return 0;
1028 }
1029
1030 static int fiq_debugger_probe(struct platform_device *pdev)
1031 {
1032         int ret;
1033         struct fiq_debugger_pdata *pdata = dev_get_platdata(&pdev->dev);
1034         struct fiq_debugger_state *state;
1035         int fiq;
1036         int uart_irq;
1037
1038         if (!pdata->uart_getc || !pdata->uart_putc)
1039                 return -EINVAL;
1040         if ((pdata->uart_enable && !pdata->uart_disable) ||
1041             (!pdata->uart_enable && pdata->uart_disable))
1042                 return -EINVAL;
1043
1044         fiq = platform_get_irq_byname(pdev, "fiq");
1045         uart_irq = platform_get_irq_byname(pdev, "uart_irq");
1046
1047         /* uart_irq mode and fiq mode are mutually exclusive, but one of them
1048          * is required */
1049         if ((uart_irq < 0 && fiq < 0) || (uart_irq >= 0 && fiq >= 0))
1050                 return -EINVAL;
1051         if (fiq >= 0 && !pdata->fiq_enable)
1052                 return -EINVAL;
1053
1054         state = kzalloc(sizeof(*state), GFP_KERNEL);
1055         setup_timer(&state->sleep_timer, sleep_timer_expired,
1056                     (unsigned long)state);
1057         state->pdata = pdata;
1058         state->pdev = pdev;
1059         state->no_sleep = initial_no_sleep;
1060         state->debug_enable = initial_debug_enable;
1061         state->console_enable = initial_console_enable;
1062
1063         state->fiq = fiq;
1064         state->uart_irq = uart_irq;
1065         state->signal_irq = platform_get_irq_byname(pdev, "signal");
1066         state->wakeup_irq = platform_get_irq_byname(pdev, "wakeup");
1067
1068         platform_set_drvdata(pdev, state);
1069
1070         spin_lock_init(&state->sleep_timer_lock);
1071
1072         if (state->wakeup_irq < 0 && debug_have_fiq(state))
1073                 state->no_sleep = true;
1074         state->ignore_next_wakeup_irq = !state->no_sleep;
1075
1076         wake_lock_init(&state->debugger_wake_lock,
1077                         WAKE_LOCK_SUSPEND, "serial-debug");
1078
1079         state->clk = clk_get(&pdev->dev, NULL);
1080         if (IS_ERR(state->clk))
1081                 state->clk = NULL;
1082
1083         /* do not call pdata->uart_enable here since uart_init may still
1084          * need to do some initialization before uart_enable can work.
1085          * So, only try to manage the clock during init.
1086          */
1087         if (state->clk)
1088                 clk_enable(state->clk);
1089
1090         if (pdata->uart_init) {
1091                 ret = pdata->uart_init(pdev);
1092                 if (ret)
1093                         goto err_uart_init;
1094         }
1095
1096         debug_printf_nfiq(state, "<hit enter %sto activate fiq debugger>\n",
1097                                 state->no_sleep ? "" : "twice ");
1098
1099         if (debug_have_fiq(state)) {
1100                 state->handler.fiq = debug_fiq;
1101                 state->handler.resume = debug_resume;
1102                 ret = fiq_glue_register_handler(&state->handler);
1103                 if (ret) {
1104                         pr_err("%s: could not install fiq handler\n", __func__);
1105                         goto err_register_fiq;
1106                 }
1107
1108                 pdata->fiq_enable(pdev, state->fiq, 1);
1109         } else {
1110                 ret = request_irq(state->uart_irq, debug_uart_irq,
1111                                   IRQF_NO_SUSPEND, "debug", state);
1112                 if (ret) {
1113                         pr_err("%s: could not install irq handler\n", __func__);
1114                         goto err_register_irq;
1115                 }
1116
1117                 /* for irq-only mode, we want this irq to wake us up, if it
1118                  * can.
1119                  */
1120                 enable_irq_wake(state->uart_irq);
1121         }
1122
1123         if (state->clk)
1124                 clk_disable(state->clk);
1125
1126         if (state->signal_irq >= 0) {
1127                 ret = request_irq(state->signal_irq, debug_signal_irq,
1128                           IRQF_TRIGGER_RISING, "debug-signal", state);
1129                 if (ret)
1130                         pr_err("serial_debugger: could not install signal_irq");
1131         }
1132
1133         if (state->wakeup_irq >= 0) {
1134                 ret = request_irq(state->wakeup_irq, wakeup_irq_handler,
1135                                   IRQF_TRIGGER_FALLING | IRQF_DISABLED,
1136                                   "debug-wakeup", state);
1137                 if (ret) {
1138                         pr_err("serial_debugger: "
1139                                 "could not install wakeup irq\n");
1140                         state->wakeup_irq = -1;
1141                 } else {
1142                         ret = enable_irq_wake(state->wakeup_irq);
1143                         if (ret) {
1144                                 pr_err("serial_debugger: "
1145                                         "could not enable wakeup\n");
1146                                 state->wakeup_irq_no_set_wake = true;
1147                         }
1148                 }
1149         }
1150         if (state->no_sleep)
1151                 handle_wakeup(state);
1152
1153 #if defined(CONFIG_FIQ_DEBUGGER_CONSOLE)
1154         state->console = fiq_debugger_console;
1155         register_console(&state->console);
1156         fiq_debugger_tty_init(state);
1157 #endif
1158         return 0;
1159
1160 err_register_irq:
1161 err_register_fiq:
1162         if (pdata->uart_free)
1163                 pdata->uart_free(pdev);
1164 err_uart_init:
1165         if (state->clk)
1166                 clk_disable(state->clk);
1167         if (state->clk)
1168                 clk_put(state->clk);
1169         wake_lock_destroy(&state->debugger_wake_lock);
1170         platform_set_drvdata(pdev, NULL);
1171         kfree(state);
1172         return ret;
1173 }
1174
1175 static const struct dev_pm_ops fiq_debugger_dev_pm_ops = {
1176         .suspend        = fiq_debugger_dev_suspend,
1177         .resume         = fiq_debugger_dev_resume,
1178 };
1179
1180 static struct platform_driver fiq_debugger_driver = {
1181         .probe  = fiq_debugger_probe,
1182         .driver = {
1183                 .name   = "fiq_debugger",
1184                 .pm     = &fiq_debugger_dev_pm_ops,
1185         },
1186 };
1187
1188 static int __init fiq_debugger_init(void)
1189 {
1190         return platform_driver_register(&fiq_debugger_driver);
1191 }
1192
1193 postcore_initcall(fiq_debugger_init);