fiq_debugger: Call fiq_debugger_printf through a function pointer from cpu specific code

This allows the output from the register and stack trace code to be
sent elsewhere.

Change-Id: I41bb0d5a25e1b9ca55feef5dbd675818b2f832d5
Signed-off-by: Arve Hjønnevåg <arve@android.com>

4 files changed, 123 insertions, 119 deletions

diff --git a/drivers/staging/android/fiq_debugger/fiq_debugger.c b/drivers/staging/android/fiq_debugger/fiq_debugger.c
index 5516d3113b94..7d6b4ae8a2cd 100644
--- a/drivers/staging/android/fiq_debugger/fiq_debugger.c
+++ b/drivers/staging/android/fiq_debugger/fiq_debugger.c
@@ -54,6 +54,7 @@ struct fiq_debugger_state {
 #ifdef CONFIG_FIQ_GLUE
 	struct fiq_glue_handler handler;
 #endif
+	struct fiq_debugger_output output;
 
 	int fiq;
 	int uart_irq;
@@ -229,18 +230,19 @@ static void fiq_debugger_dump_kernel_log(struct fiq_debugger_state *state)
 	}
 }
 
-int fiq_debugger_printf(void *cookie, const char *fmt, ...)
+static void fiq_debugger_printf(struct fiq_debugger_output *output,
+			       const char *fmt, ...)
 {
-	struct fiq_debugger_state *state = cookie;
+	struct fiq_debugger_state *state;
 	char buf[256];
 	va_list ap;
 
+	state = container_of(output, struct fiq_debugger_state, output);
 	va_start(ap, fmt);
 	vsnprintf(buf, sizeof(buf), fmt, ap);
 	va_end(ap);
 
 	fiq_debugger_puts(state, buf);
-	return state->debug_abort;
 }
 
 /* Safe outside fiq context */
@@ -267,13 +269,13 @@ static void fiq_debugger_dump_irqs(struct fiq_debugger_state *state)
 	int n;
 	struct irq_desc *desc;
 
-	fiq_debugger_printf(state,
+	fiq_debugger_printf(&state->output,
 			"irqnr       total  since-last   status  name\n");
 	for_each_irq_desc(n, desc) {
 		struct irqaction *act = desc->action;
 		if (!act && !kstat_irqs(n))
 			continue;
-		fiq_debugger_printf(state, "%5d: %10u %11u %8x  %s\n", n,
+		fiq_debugger_printf(&state->output, "%5d: %10u %11u %8x  %s\n", n,
 			kstat_irqs(n),
 			kstat_irqs(n) - state->last_irqs[n],
 			desc->status_use_accessors,
@@ -289,18 +291,18 @@ static void fiq_debugger_do_ps(struct fiq_debugger_state *state)
 	unsigned task_state;
 	static const char stat_nam[] = "RSDTtZX";
 
-	fiq_debugger_printf(state, "pid   ppid  prio task            pc\n");
+	fiq_debugger_printf(&state->output, "pid   ppid  prio task            pc\n");
 	read_lock(&tasklist_lock);
 	do_each_thread(g, p) {
 		task_state = p->state ? __ffs(p->state) + 1 : 0;
-		fiq_debugger_printf(state,
+		fiq_debugger_printf(&state->output,
 			     "%5d %5d %4d ", p->pid, p->parent->pid, p->prio);
-		fiq_debugger_printf(state, "%-13.13s %c", p->comm,
+		fiq_debugger_printf(&state->output, "%-13.13s %c", p->comm,
 			     task_state >= sizeof(stat_nam) ? '?' : stat_nam[task_state]);
 		if (task_state == TASK_RUNNING)
-			fiq_debugger_printf(state, " running\n");
+			fiq_debugger_printf(&state->output, " running\n");
 		else
-			fiq_debugger_printf(state, " %08lx\n",
+			fiq_debugger_printf(&state->output, " %08lx\n",
 					thread_saved_pc(p));
 	} while_each_thread(g, p);
 	read_unlock(&tasklist_lock);
@@ -332,7 +334,7 @@ static void fiq_debugger_end_syslog_dump(struct fiq_debugger_state *state)
 static void fiq_debugger_do_sysrq(struct fiq_debugger_state *state, char rq)
 {
 	if ((rq == 'g' || rq == 'G') && !fiq_kgdb_enable) {
-		fiq_debugger_printf(state, "sysrq-g blocked\n");
+		fiq_debugger_printf(&state->output, "sysrq-g blocked\n");
 		return;
 	}
 	fiq_debugger_begin_syslog_dump(state);
@@ -344,11 +346,11 @@ static void fiq_debugger_do_sysrq(struct fiq_debugger_state *state, char rq)
 static void fiq_debugger_do_kgdb(struct fiq_debugger_state *state)
 {
 	if (!fiq_kgdb_enable) {
-		fiq_debugger_printf(state, "kgdb through fiq debugger not enabled\n");
+		fiq_debugger_printf(&state->output, "kgdb through fiq debugger not enabled\n");
 		return;
 	}
 
-	fiq_debugger_printf(state, "enabling console and triggering kgdb\n");
+	fiq_debugger_printf(&state->output, "enabling console and triggering kgdb\n");
 	state->console_enable = true;
 	handle_sysrq('g');
 }
@@ -361,7 +363,7 @@ static void fiq_debugger_schedule_work(struct fiq_debugger_state *state,
 
 	spin_lock_irqsave(&state->work_lock, flags);
 	if (state->work_cmd[0] != '\0') {
-		fiq_debugger_printf(state, "work command processor busy\n");
+		fiq_debugger_printf(&state->output, "work command processor busy\n");
 		spin_unlock_irqrestore(&state->work_lock, flags);
 		return;
 	}
@@ -398,7 +400,7 @@ static void fiq_debugger_work(struct work_struct *work)
 		else
 			kernel_restart(NULL);
 	} else {
-		fiq_debugger_printf(state, "unknown work command '%s'\n",
+		fiq_debugger_printf(&state->output, "unknown work command '%s'\n",
 				work_cmd);
 	}
 }
@@ -422,7 +424,7 @@ static void fiq_debugger_irq_exec(struct fiq_debugger_state *state, char *cmd)
 
 static void fiq_debugger_help(struct fiq_debugger_state *state)
 {
-	fiq_debugger_printf(state,
+	fiq_debugger_printf(&state->output,
 				"FIQ Debugger commands:\n"
 				" pc            PC status\n"
 				" regs          Register dump\n"
@@ -433,18 +435,18 @@ static void fiq_debugger_help(struct fiq_debugger_state *state)
 				" irqs          Interupt status\n"
 				" kmsg          Kernel log\n"
 				" version       Kernel version\n");
-	fiq_debugger_printf(state,
+	fiq_debugger_printf(&state->output,
 				" sleep         Allow sleep while in FIQ\n"
 				" nosleep       Disable sleep while in FIQ\n"
 				" console       Switch terminal to console\n"
 				" cpu           Current CPU\n"
 				" cpu <number>  Switch to CPU<number>\n");
-	fiq_debugger_printf(state,
+	fiq_debugger_printf(&state->output,
 				" ps            Process list\n"
 				" sysrq         sysrq options\n"
 				" sysrq <param> Execute sysrq with <param>\n");
 #ifdef CONFIG_KGDB
-	fiq_debugger_printf(state,
+	fiq_debugger_printf(&state->output,
 				" kgdb          Enter kernel debugger\n");
 #endif
 }
@@ -477,13 +479,13 @@ static bool fiq_debugger_fiq_exec(struct fiq_debugger_state *state,
 	if (!strcmp(cmd, "help") || !strcmp(cmd, "?")) {
 		fiq_debugger_help(state);
 	} else if (!strcmp(cmd, "pc")) {
-		fiq_debugger_dump_pc(state, regs);
+		fiq_debugger_dump_pc(&state->output, regs);
 	} else if (!strcmp(cmd, "regs")) {
-		fiq_debugger_dump_regs(state, regs);
+		fiq_debugger_dump_regs(&state->output, regs);
 	} else if (!strcmp(cmd, "allregs")) {
-		fiq_debugger_dump_allregs(state, regs);
+		fiq_debugger_dump_allregs(&state->output, regs);
 	} else if (!strcmp(cmd, "bt")) {
-		fiq_debugger_dump_stacktrace(state, regs, 100, svc_sp);
+		fiq_debugger_dump_stacktrace(&state->output, regs, 100, svc_sp);
 	} else if (!strncmp(cmd, "reset", 5)) {
 		cmd += 5;
 		while (*cmd == ' ')
@@ -500,29 +502,29 @@ static bool fiq_debugger_fiq_exec(struct fiq_debugger_state *state,
 	} else if (!strcmp(cmd, "kmsg")) {
 		fiq_debugger_dump_kernel_log(state);
 	} else if (!strcmp(cmd, "version")) {
-		fiq_debugger_printf(state, "%s\n", linux_banner);
+		fiq_debugger_printf(&state->output, "%s\n", linux_banner);
 	} else if (!strcmp(cmd, "sleep")) {
 		state->no_sleep = false;
-		fiq_debugger_printf(state, "enabling sleep\n");
+		fiq_debugger_printf(&state->output, "enabling sleep\n");
 	} else if (!strcmp(cmd, "nosleep")) {
 		state->no_sleep = true;
-		fiq_debugger_printf(state, "disabling sleep\n");
+		fiq_debugger_printf(&state->output, "disabling sleep\n");
 	} else if (!strcmp(cmd, "console")) {
-		fiq_debugger_printf(state, "console mode\n");
+		fiq_debugger_printf(&state->output, "console mode\n");
 		fiq_debugger_uart_flush(state);
 		state->console_enable = true;
 	} else if (!strcmp(cmd, "cpu")) {
-		fiq_debugger_printf(state, "cpu %d\n", state->current_cpu);
+		fiq_debugger_printf(&state->output, "cpu %d\n", state->current_cpu);
 	} else if (!strncmp(cmd, "cpu ", 4)) {
 		unsigned long cpu = 0;
 		if (strict_strtoul(cmd + 4, 10, &cpu) == 0)
 			fiq_debugger_switch_cpu(state, cpu);
 		else
-			fiq_debugger_printf(state, "invalid cpu\n");
-		fiq_debugger_printf(state, "cpu %d\n", state->current_cpu);
+			fiq_debugger_printf(&state->output, "invalid cpu\n");
+		fiq_debugger_printf(&state->output, "cpu %d\n", state->current_cpu);
 	} else {
 		if (state->debug_busy) {
-			fiq_debugger_printf(state,
+			fiq_debugger_printf(&state->output,
 				"command processor busy. trying to abort.\n");
 			state->debug_abort = -1;
 		} else {
@@ -645,7 +647,7 @@ static bool fiq_debugger_handle_uart_interrupt(struct fiq_debugger_state *state,
 					MAX_UNHANDLED_FIQ_COUNT)
 			return false;
 
-		fiq_debugger_printf(state,
+		fiq_debugger_printf(&state->output,
 			"fiq_debugger: cpu %d not responding, "
 			"reverting to cpu %d\n", state->current_cpu,
 			this_cpu);
@@ -1053,6 +1055,7 @@ static int fiq_debugger_probe(struct platform_device *pdev)
 		return -EINVAL;
 
 	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	state->output.printf = fiq_debugger_printf;
 	setup_timer(&state->sleep_timer, fiq_debugger_sleep_timer_expired,
 		    (unsigned long)state);
 	state->pdata = pdata;
diff --git a/drivers/staging/android/fiq_debugger/fiq_debugger_arm.c b/drivers/staging/android/fiq_debugger/fiq_debugger_arm.c
index fca12737d224..8b3e0137be1a 100644
--- a/drivers/staging/android/fiq_debugger/fiq_debugger_arm.c
+++ b/drivers/staging/android/fiq_debugger/fiq_debugger_arm.c
@@ -34,27 +34,27 @@ static char *mode_name(unsigned cpsr)
 	}
 }
 
-void fiq_debugger_dump_pc(struct fiq_debugger_state *state,
+void fiq_debugger_dump_pc(struct fiq_debugger_output *output,
 		const struct pt_regs *regs)
 {
-	fiq_debugger_printf(state, " pc %08x cpsr %08x mode %s\n",
+	output->printf(output, " pc %08x cpsr %08x mode %s\n",
 		regs->ARM_pc, regs->ARM_cpsr, mode_name(regs->ARM_cpsr));
 }
 
-void fiq_debugger_dump_regs(struct fiq_debugger_state *state,
+void fiq_debugger_dump_regs(struct fiq_debugger_output *output,
 		const struct pt_regs *regs)
 {
-	fiq_debugger_printf(state,
+	output->printf(output,
 			" r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",
 			regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
-	fiq_debugger_printf(state,
+	output->printf(output,
 			" r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",
 			regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
-	fiq_debugger_printf(state,
+	output->printf(output,
 			" r8 %08x  r9 %08x r10 %08x r11 %08x  mode %s\n",
 			regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp,
 			mode_name(regs->ARM_cpsr));
-	fiq_debugger_printf(state,
+	output->printf(output,
 			" ip %08x  sp %08x  lr %08x  pc %08x cpsr %08x\n",
 			regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc,
 			regs->ARM_cpsr);
@@ -112,43 +112,43 @@ static void __naked get_mode_regs(struct mode_regs *regs)
 }
 
 
-void fiq_debugger_dump_allregs(struct fiq_debugger_state *state,
+void fiq_debugger_dump_allregs(struct fiq_debugger_output *output,
 		const struct pt_regs *regs)
 {
 	struct mode_regs mode_regs;
 	unsigned long mode = regs->ARM_cpsr & MODE_MASK;
 
-	fiq_debugger_dump_regs(state, regs);
+	fiq_debugger_dump_regs(output, regs);
 	get_mode_regs(&mode_regs);
 
-	fiq_debugger_printf(state,
+	output->printf(output,
 			"%csvc: sp %08x  lr %08x  spsr %08x\n",
 			mode == SVC_MODE ? '*' : ' ',
 			mode_regs.sp_svc, mode_regs.lr_svc, mode_regs.spsr_svc);
-	fiq_debugger_printf(state,
+	output->printf(output,
 			"%cabt: sp %08x  lr %08x  spsr %08x\n",
 			mode == ABT_MODE ? '*' : ' ',
 			mode_regs.sp_abt, mode_regs.lr_abt, mode_regs.spsr_abt);
-	fiq_debugger_printf(state,
+	output->printf(output,
 			"%cund: sp %08x  lr %08x  spsr %08x\n",
 			mode == UND_MODE ? '*' : ' ',
 			mode_regs.sp_und, mode_regs.lr_und, mode_regs.spsr_und);
-	fiq_debugger_printf(state,
+	output->printf(output,
 			"%cirq: sp %08x  lr %08x  spsr %08x\n",
 			mode == IRQ_MODE ? '*' : ' ',
 			mode_regs.sp_irq, mode_regs.lr_irq, mode_regs.spsr_irq);
-	fiq_debugger_printf(state,
+	output->printf(output,
 			"%cfiq: r8 %08x  r9 %08x  r10 %08x  r11 %08x  r12 %08x\n",
 			mode == FIQ_MODE ? '*' : ' ',
 			mode_regs.r8_fiq, mode_regs.r9_fiq, mode_regs.r10_fiq,
 			mode_regs.r11_fiq, mode_regs.r12_fiq);
-	fiq_debugger_printf(state,
+	output->printf(output,
 			" fiq: sp %08x  lr %08x  spsr %08x\n",
 			mode_regs.sp_fiq, mode_regs.lr_fiq, mode_regs.spsr_fiq);
 }
 
 struct stacktrace_state {
-	struct fiq_debugger_state *state;
+	struct fiq_debugger_output *output;
 	unsigned int depth;
 };
 
@@ -157,14 +157,14 @@ static int report_trace(struct stackframe *frame, void *d)
 	struct stacktrace_state *sts = d;
 
 	if (sts->depth) {
-		fiq_debugger_printf(sts->state,
+		sts->output->printf(sts->output,
 			"  pc: %p (%pF), lr %p (%pF), sp %p, fp %p\n",
 			frame->pc, frame->pc, frame->lr, frame->lr,
 			frame->sp, frame->fp);
 		sts->depth--;
 		return 0;
 	}
-	fiq_debugger_printf(sts->state, "  ...\n");
+	sts->output->printf(sts->output, "  ...\n");
 
 	return sts->depth == 0;
 }
@@ -175,24 +175,24 @@ struct frame_tail {
 	unsigned long lr;
 } __attribute__((packed));
 
-static struct frame_tail *user_backtrace(struct fiq_debugger_state *state,
+static struct frame_tail *user_backtrace(struct fiq_debugger_output *output,
 					struct frame_tail *tail)
 {
 	struct frame_tail buftail[2];
 
 	/* Also check accessibility of one struct frame_tail beyond */
 	if (!access_ok(VERIFY_READ, tail, sizeof(buftail))) {
-		fiq_debugger_printf(state, "  invalid frame pointer %p\n",
+		output->printf(output, "  invalid frame pointer %p\n",
 				tail);
 		return NULL;
 	}
 	if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail))) {
-		fiq_debugger_printf(state,
+		output->printf(output,
 			"  failed to copy frame pointer %p\n", tail);
 		return NULL;
 	}
 
-	fiq_debugger_printf(state, "  %p\n", buftail[0].lr);
+	output->printf(output, "  %p\n", buftail[0].lr);
 
 	/* frame pointers should strictly progress back up the stack
 	 * (towards higher addresses) */
@@ -202,7 +202,7 @@ static struct frame_tail *user_backtrace(struct fiq_debugger_state *state,
 	return buftail[0].fp-1;
 }
 
-void fiq_debugger_dump_stacktrace(struct fiq_debugger_state *state,
+void fiq_debugger_dump_stacktrace(struct fiq_debugger_output *output,
 		const struct pt_regs *regs, unsigned int depth, void *ssp)
 {
 	struct frame_tail *tail;
@@ -210,15 +210,15 @@ void fiq_debugger_dump_stacktrace(struct fiq_debugger_state *state,
 	struct stacktrace_state sts;
 
 	sts.depth = depth;
-	sts.state = state;
+	sts.output = output;
 	*current_thread_info() = *real_thread_info;
 
 	if (!current)
-		fiq_debugger_printf(state, "current NULL\n");
+		output->printf(output, "current NULL\n");
 	else
-		fiq_debugger_printf(state, "pid: %d  comm: %s\n",
+		output->printf(output, "pid: %d  comm: %s\n",
 			current->pid, current->comm);
-	fiq_debugger_dump_regs(state, regs);
+	fiq_debugger_dump_regs(output, regs);
 
 	if (!user_mode(regs)) {
 		struct stackframe frame;
@@ -226,7 +226,7 @@ void fiq_debugger_dump_stacktrace(struct fiq_debugger_state *state,
 		frame.sp = regs->ARM_sp;
 		frame.lr = regs->ARM_lr;
 		frame.pc = regs->ARM_pc;
-		fiq_debugger_printf(state,
+		output->printf(output,
 			"  pc: %p (%pF), lr %p (%pF), sp %p, fp %p\n",
 			regs->ARM_pc, regs->ARM_pc, regs->ARM_lr, regs->ARM_lr,
 			regs->ARM_sp, regs->ARM_fp);
@@ -236,5 +236,5 @@ void fiq_debugger_dump_stacktrace(struct fiq_debugger_state *state,
 
 	tail = ((struct frame_tail *) regs->ARM_fp) - 1;
 	while (depth-- && tail && !((unsigned long) tail & 3))
-		tail = user_backtrace(state, tail);
+		tail = user_backtrace(output, tail);
 }
diff --git a/drivers/staging/android/fiq_debugger/fiq_debugger_arm64.c b/drivers/staging/android/fiq_debugger/fiq_debugger_arm64.c
index cbca82b70533..99c6584fcfa5 100644
--- a/drivers/staging/android/fiq_debugger/fiq_debugger_arm64.c
+++ b/drivers/staging/android/fiq_debugger/fiq_debugger_arm64.c
@@ -34,79 +34,79 @@ static char *mode_name(const struct pt_regs *regs)
 	}
 }
 
-void fiq_debugger_dump_pc(struct fiq_debugger_state *state,
+void fiq_debugger_dump_pc(struct fiq_debugger_output *output,
 		const struct pt_regs *regs)
 {
-	fiq_debugger_printf(state, " pc %016lx cpsr %08lx mode %s\n",
+	output->printf(output, " pc %016lx cpsr %08lx mode %s\n",
 		regs->pc, regs->pstate, mode_name(regs));
 }
 
-void fiq_debugger_dump_regs_aarch32(struct fiq_debugger_state *state,
+void fiq_debugger_dump_regs_aarch32(struct fiq_debugger_output *output,
 		const struct pt_regs *regs)
 {
-	fiq_debugger_printf(state, " r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",
+	output->printf(output, " r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",
 			regs->compat_usr(0), regs->compat_usr(1),
 			regs->compat_usr(2), regs->compat_usr(3));
-	fiq_debugger_printf(state, " r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",
+	output->printf(output, " r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",
 			regs->compat_usr(4), regs->compat_usr(5),
 			regs->compat_usr(6), regs->compat_usr(7));
-	fiq_debugger_printf(state, " r8 %08x  r9 %08x r10 %08x r11 %08x\n",
+	output->printf(output, " r8 %08x  r9 %08x r10 %08x r11 %08x\n",
 			regs->compat_usr(8), regs->compat_usr(9),
 			regs->compat_usr(10), regs->compat_usr(11));
-	fiq_debugger_printf(state, " ip %08x  sp %08x  lr %08x  pc %08x\n",
+	output->printf(output, " ip %08x  sp %08x  lr %08x  pc %08x\n",
 			regs->compat_usr(12), regs->compat_sp,
 			regs->compat_lr, regs->pc);
-	fiq_debugger_printf(state, " cpsr %08x (%s)\n",
+	output->printf(output, " cpsr %08x (%s)\n",
 			regs->pstate, mode_name(regs));
 }
 
-void fiq_debugger_dump_regs_aarch64(struct fiq_debugger_state *state,
+void fiq_debugger_dump_regs_aarch64(struct fiq_debugger_output *output,
 		const struct pt_regs *regs)
 {
 
-	fiq_debugger_printf(state, "  x0 %016lx   x1 %016lx\n",
+	output->printf(output, "  x0 %016lx   x1 %016lx\n",
 			regs->regs[0], regs->regs[1]);
-	fiq_debugger_printf(state, "  x2 %016lx   x3 %016lx\n",
+	output->printf(output, "  x2 %016lx   x3 %016lx\n",
 			regs->regs[2], regs->regs[3]);
-	fiq_debugger_printf(state, "  x4 %016lx   x5 %016lx\n",
+	output->printf(output, "  x4 %016lx   x5 %016lx\n",
 			regs->regs[4], regs->regs[5]);
-	fiq_debugger_printf(state, "  x6 %016lx   x7 %016lx\n",
+	output->printf(output, "  x6 %016lx   x7 %016lx\n",
 			regs->regs[6], regs->regs[7]);
-	fiq_debugger_printf(state, "  x8 %016lx   x9 %016lx\n",
+	output->printf(output, "  x8 %016lx   x9 %016lx\n",
 			regs->regs[8], regs->regs[9]);
-	fiq_debugger_printf(state, " x10 %016lx  x11 %016lx\n",
+	output->printf(output, " x10 %016lx  x11 %016lx\n",
 			regs->regs[10], regs->regs[11]);
-	fiq_debugger_printf(state, " x12 %016lx  x13 %016lx\n",
+	output->printf(output, " x12 %016lx  x13 %016lx\n",
 			regs->regs[12], regs->regs[13]);
-	fiq_debugger_printf(state, " x14 %016lx  x15 %016lx\n",
+	output->printf(output, " x14 %016lx  x15 %016lx\n",
 			regs->regs[14], regs->regs[15]);
-	fiq_debugger_printf(state, " x16 %016lx  x17 %016lx\n",
+	output->printf(output, " x16 %016lx  x17 %016lx\n",
 			regs->regs[16], regs->regs[17]);
-	fiq_debugger_printf(state, " x18 %016lx  x19 %016lx\n",
+	output->printf(output, " x18 %016lx  x19 %016lx\n",
 			regs->regs[18], regs->regs[19]);
-	fiq_debugger_printf(state, " x20 %016lx  x21 %016lx\n",
+	output->printf(output, " x20 %016lx  x21 %016lx\n",
 			regs->regs[20], regs->regs[21]);
-	fiq_debugger_printf(state, " x22 %016lx  x23 %016lx\n",
+	output->printf(output, " x22 %016lx  x23 %016lx\n",
 			regs->regs[22], regs->regs[23]);
-	fiq_debugger_printf(state, " x24 %016lx  x25 %016lx\n",
+	output->printf(output, " x24 %016lx  x25 %016lx\n",
 			regs->regs[24], regs->regs[25]);
-	fiq_debugger_printf(state, " x26 %016lx  x27 %016lx\n",
+	output->printf(output, " x26 %016lx  x27 %016lx\n",
 			regs->regs[26], regs->regs[27]);
-	fiq_debugger_printf(state, " x28 %016lx  x29 %016lx\n",
+	output->printf(output, " x28 %016lx  x29 %016lx\n",
 			regs->regs[28], regs->regs[29]);
-	fiq_debugger_printf(state, " x30 %016lx   sp %016lx\n",
+	output->printf(output, " x30 %016lx   sp %016lx\n",
 			regs->regs[30], regs->sp);
-	fiq_debugger_printf(state, "  pc %016lx cpsr %08x (%s)\n",
+	output->printf(output, "  pc %016lx cpsr %08x (%s)\n",
 			regs->pc, regs->pstate, mode_name(regs));
 }
 
-void fiq_debugger_dump_regs(struct fiq_debugger_state *state,
+void fiq_debugger_dump_regs(struct fiq_debugger_output *output,
 		const struct pt_regs *regs)
 {
 	if (compat_user_mode(regs))
-		fiq_debugger_dump_regs_aarch32(state, regs);
+		fiq_debugger_dump_regs_aarch32(output, regs);
 	else
-		fiq_debugger_dump_regs_aarch64(state, regs);
+		fiq_debugger_dump_regs_aarch64(output, regs);
 }
 
 #define READ_SPECIAL_REG(x) ({ \
@@ -115,45 +115,45 @@ void fiq_debugger_dump_regs(struct fiq_debugger_state *state,
 	val; \
 })
 
-void fiq_debugger_dump_allregs(struct fiq_debugger_state *state,
+void fiq_debugger_dump_allregs(struct fiq_debugger_output *output,
 		const struct pt_regs *regs)
 {
 	u32 pstate = READ_SPECIAL_REG(CurrentEl);
 	bool in_el2 = (pstate & PSR_MODE_MASK) >= PSR_MODE_EL2t;
 
-	fiq_debugger_dump_regs(state, regs);
+	fiq_debugger_dump_regs(output, regs);
 
-	fiq_debugger_printf(state, " sp_el0   %016lx\n",
+	output->printf(output, " sp_el0   %016lx\n",
 			READ_SPECIAL_REG(sp_el0));
 
 	if (in_el2)
-		fiq_debugger_printf(state, " sp_el1   %016lx\n",
+		output->printf(output, " sp_el1   %016lx\n",
 				READ_SPECIAL_REG(sp_el1));
 
-	fiq_debugger_printf(state, " elr_el1  %016lx\n",
+	output->printf(output, " elr_el1  %016lx\n",
 			READ_SPECIAL_REG(elr_el1));
 
-	fiq_debugger_printf(state, " spsr_el1 %08lx\n",
+	output->printf(output, " spsr_el1 %08lx\n",
 			READ_SPECIAL_REG(spsr_el1));
 
 	if (in_el2) {
-		fiq_debugger_printf(state, " spsr_irq %08lx\n",
+		output->printf(output, " spsr_irq %08lx\n",
 				READ_SPECIAL_REG(spsr_irq));
-		fiq_debugger_printf(state, " spsr_abt %08lx\n",
+		output->printf(output, " spsr_abt %08lx\n",
 				READ_SPECIAL_REG(spsr_abt));
-		fiq_debugger_printf(state, " spsr_und %08lx\n",
+		output->printf(output, " spsr_und %08lx\n",
 				READ_SPECIAL_REG(spsr_und));
-		fiq_debugger_printf(state, " spsr_fiq %08lx\n",
+		output->printf(output, " spsr_fiq %08lx\n",
 				READ_SPECIAL_REG(spsr_fiq));
-		fiq_debugger_printf(state, " spsr_el2 %08lx\n",
+		output->printf(output, " spsr_el2 %08lx\n",
 				READ_SPECIAL_REG(elr_el2));
-		fiq_debugger_printf(state, " spsr_el2 %08lx\n",
+		output->printf(output, " spsr_el2 %08lx\n",
 				READ_SPECIAL_REG(spsr_el2));
 	}
 }
 
 struct stacktrace_state {
-	struct fiq_debugger_state *state;
+	struct fiq_debugger_output *output;
 	unsigned int depth;
 };
 
@@ -162,41 +162,41 @@ static int report_trace(struct stackframe *frame, void *d)
 	struct stacktrace_state *sts = d;
 
 	if (sts->depth) {
-		fiq_debugger_printf(sts->state, "%pF:\n", frame->pc);
-		fiq_debugger_printf(sts->state,
+		sts->output->printf(sts->output, "%pF:\n", frame->pc);
+		sts->output->printf(sts->output,
 				"  pc %016lx   sp %016lx   fp %016lx\n",
 				frame->pc, frame->sp, frame->fp);
 		sts->depth--;
 		return 0;
 	}
-	fiq_debugger_printf(sts->state, "  ...\n");
+	sts->output->printf(sts->output, "  ...\n");
 
 	return sts->depth == 0;
 }
 
-void fiq_debugger_dump_stacktrace(struct fiq_debugger_state *state,
+void fiq_debugger_dump_stacktrace(struct fiq_debugger_output *output,
 		const struct pt_regs *regs, unsigned int depth, void *ssp)
 {
 	struct thread_info *real_thread_info = THREAD_INFO(ssp);
 	struct stacktrace_state sts;
 
 	sts.depth = depth;
-	sts.state = state;
+	sts.output = output;
 	*current_thread_info() = *real_thread_info;
 
 	if (!current)
-		fiq_debugger_printf(state, "current NULL\n");
+		output->printf(output, "current NULL\n");
 	else
-		fiq_debugger_printf(state, "pid: %d  comm: %s\n",
+		output->printf(output, "pid: %d  comm: %s\n",
 			current->pid, current->comm);
-	fiq_debugger_dump_regs(state, regs);
+	fiq_debugger_dump_regs(output, regs);
 
 	if (!user_mode(regs)) {
 		struct stackframe frame;
 		frame.fp = regs->regs[29];
 		frame.sp = regs->sp;
 		frame.pc = regs->pc;
-		fiq_debugger_printf(state, "\n");
+		output->printf(output, "\n");
 		walk_stackframe(&frame, report_trace, &sts);
 	}
 }
diff --git a/drivers/staging/android/fiq_debugger/fiq_debugger_priv.h b/drivers/staging/android/fiq_debugger/fiq_debugger_priv.h
index 746cf1b5d55b..d5d051f727a8 100644
--- a/drivers/staging/android/fiq_debugger/fiq_debugger_priv.h
+++ b/drivers/staging/android/fiq_debugger/fiq_debugger_priv.h
@@ -19,18 +19,19 @@
 #define THREAD_INFO(sp) ((struct thread_info *) \
 		((unsigned long)(sp) & ~(THREAD_SIZE - 1)))
 
-struct fiq_debugger_state;
-struct pt_regs;
+struct fiq_debugger_output {
+	void (*printf)(struct fiq_debugger_output *output, const char *fmt, ...);
+};
 
-int fiq_debugger_printf(void *cookie, const char *fmt, ...);
+struct pt_regs;
 
-void fiq_debugger_dump_pc(struct fiq_debugger_state *state,
+void fiq_debugger_dump_pc(struct fiq_debugger_output *output,
 		const struct pt_regs *regs);
-void fiq_debugger_dump_regs(struct fiq_debugger_state *state,
+void fiq_debugger_dump_regs(struct fiq_debugger_output *output,
 		const struct pt_regs *regs);
-void fiq_debugger_dump_allregs(struct fiq_debugger_state *state,
+void fiq_debugger_dump_allregs(struct fiq_debugger_output *output,
 		const struct pt_regs *regs);
-void fiq_debugger_dump_stacktrace(struct fiq_debugger_state *state,
+void fiq_debugger_dump_stacktrace(struct fiq_debugger_output *output,
 		const struct pt_regs *regs, unsigned int depth, void *ssp);
 
 #endif