ANDROID: ARM: fiq_debugger: Add generic fiq serial debugger

Change-Id: Ibb536c88f0dbaf4766d0599296907e35e42cbfd6
Signed-off-by: Iliyan Malchev <malchev@google.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>

[AmitP: Upstream commit 2a1f062a4a ("sched/headers: Move signal wakeup &
        sigpending methods from <linux/sched.h> into <linux/sched/signal.h>")
        moved few signal definitions to <linux/sched/signal.h>. Hence include
        that instead of <linux/sched.h>.

        Also folded following android-4.9 commit changes into this patch
        69279c68eed4 ("ANDROID: ARM: fiq_debugger: fix compiling for v3.3")
        d05890d37ecc ("ANDROID: ARM: fiq_debugger: Fix to compile on 3.7")
        9de62e0d3f24 ("ANDROID: ARM: fiq_debugger: Use kmsg_dumper to dump kernel logs")]
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>

arch/arm/common/Kconfig

@@ -19,3 +19,49 @@ config SHARP_SCOOP
 config FIQ_GLUE
 	bool
 	select FIQ
+
+config FIQ_DEBUGGER
+	bool "FIQ Mode Serial Debugger"
+	select FIQ
+	select FIQ_GLUE
+	default n
+	help
+	  The FIQ serial debugger can accept commands even when the
+	  kernel is unresponsive due to being stuck with interrupts
+	  disabled.
+
+
+config FIQ_DEBUGGER_NO_SLEEP
+	bool "Keep serial debugger active"
+	depends on FIQ_DEBUGGER
+	default n
+	help
+	  Enables the serial debugger at boot. Passing
+	  fiq_debugger.no_sleep on the kernel commandline will
+	  override this config option.
+
+config FIQ_DEBUGGER_WAKEUP_IRQ_ALWAYS_ON
+	bool "Don't disable wakeup IRQ when debugger is active"
+	depends on FIQ_DEBUGGER
+	default n
+	help
+	  Don't disable the wakeup irq when enabling the uart clock.  This will
+	  cause extra interrupts, but it makes the serial debugger usable with
+	  on some MSM radio builds that ignore the uart clock request in power
+	  collapse.
+
+config FIQ_DEBUGGER_CONSOLE
+	bool "Console on FIQ Serial Debugger port"
+	depends on FIQ_DEBUGGER
+	default n
+	help
+	  Enables a console so that printk messages are displayed on
+	  the debugger serial port as the occur.
+
+config FIQ_DEBUGGER_CONSOLE_DEFAULT_ENABLE
+	bool "Put the FIQ debugger into console mode by default"
+	depends on FIQ_DEBUGGER_CONSOLE
+	default n
+	help
+	  If enabled, this puts the fiq debugger into console mode by default.
+	  Otherwise, the fiq debugger will start out in debug mode.

arch/arm/common/Makefile

@@ -5,6 +5,7 @@
 
 obj-y				+= firmware.o
 
+obj-$(CONFIG_FIQ_DEBUGGER)	+= fiq_debugger.o
 obj-$(CONFIG_FIQ_GLUE)		+= fiq_glue.o fiq_glue_setup.o
 obj-$(CONFIG_SA1111)		+= sa1111.o
 obj-$(CONFIG_DMABOUNCE)		+= dmabounce.o

arch/arm/common/fiq_debugger_ringbuf.h

@@ -0,0 +1,94 @@
+/*
+ * arch/arm/common/fiq_debugger_ringbuf.c
+ *
+ * simple lockless ringbuffer
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+
+struct fiq_debugger_ringbuf {
+	int len;
+	int head;
+	int tail;
+	u8 buf[];
+};
+
+
+static inline struct fiq_debugger_ringbuf *fiq_debugger_ringbuf_alloc(int len)
+{
+	struct fiq_debugger_ringbuf *rbuf;
+
+	rbuf = kzalloc(sizeof(*rbuf) + len, GFP_KERNEL);
+	if (rbuf == NULL)
+		return NULL;
+
+	rbuf->len = len;
+	rbuf->head = 0;
+	rbuf->tail = 0;
+	smp_mb();
+
+	return rbuf;
+}
+
+static inline void fiq_debugger_ringbuf_free(struct fiq_debugger_ringbuf *rbuf)
+{
+	kfree(rbuf);
+}
+
+static inline int fiq_debugger_ringbuf_level(struct fiq_debugger_ringbuf *rbuf)
+{
+	int level = rbuf->head - rbuf->tail;
+
+	if (level < 0)
+		level = rbuf->len + level;
+
+	return level;
+}
+
+static inline int fiq_debugger_ringbuf_room(struct fiq_debugger_ringbuf *rbuf)
+{
+	return rbuf->len - fiq_debugger_ringbuf_level(rbuf) - 1;
+}
+
+static inline u8
+fiq_debugger_ringbuf_peek(struct fiq_debugger_ringbuf *rbuf, int i)
+{
+	return rbuf->buf[(rbuf->tail + i) % rbuf->len];
+}
+
+static inline int
+fiq_debugger_ringbuf_consume(struct fiq_debugger_ringbuf *rbuf, int count)
+{
+	count = min(count, fiq_debugger_ringbuf_level(rbuf));
+
+	rbuf->tail = (rbuf->tail + count) % rbuf->len;
+	smp_mb();
+
+	return count;
+}
+
+static inline int
+fiq_debugger_ringbuf_push(struct fiq_debugger_ringbuf *rbuf, u8 datum)
+{
+	if (fiq_debugger_ringbuf_room(rbuf) == 0)
+		return 0;
+
+	rbuf->buf[rbuf->head] = datum;
+	smp_mb();
+	rbuf->head = (rbuf->head + 1) % rbuf->len;
+	smp_mb();
+
+	return 1;
+}

arch/arm/include/asm/fiq_debugger.h

@@ -0,0 +1,64 @@
+/*
+ * arch/arm/include/asm/fiq_debugger.h
+ *
+ * Copyright (C) 2010 Google, Inc.
+ * Author: Colin Cross <ccross@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _ARCH_ARM_MACH_TEGRA_FIQ_DEBUGGER_H_
+#define _ARCH_ARM_MACH_TEGRA_FIQ_DEBUGGER_H_
+
+#include <linux/serial_core.h>
+
+#define FIQ_DEBUGGER_NO_CHAR NO_POLL_CHAR
+#define FIQ_DEBUGGER_BREAK 0x00ff0100
+
+#define FIQ_DEBUGGER_FIQ_IRQ_NAME	"fiq"
+#define FIQ_DEBUGGER_SIGNAL_IRQ_NAME	"signal"
+#define FIQ_DEBUGGER_WAKEUP_IRQ_NAME	"wakeup"
+
+/**
+ * struct fiq_debugger_pdata - fiq debugger platform data
+ * @uart_resume:	used to restore uart state right before enabling
+ *			the fiq.
+ * @uart_enable:	Do the work necessary to communicate with the uart
+ *			hw (enable clocks, etc.). This must be ref-counted.
+ * @uart_disable:	Do the work necessary to disable the uart hw
+ *			(disable clocks, etc.). This must be ref-counted.
+ * @uart_dev_suspend:	called during PM suspend, generally not needed
+ *			for real fiq mode debugger.
+ * @uart_dev_resume:	called during PM resume, generally not needed
+ *			for real fiq mode debugger.
+ */
+struct fiq_debugger_pdata {
+	int (*uart_init)(struct platform_device *pdev);
+	void (*uart_free)(struct platform_device *pdev);
+	int (*uart_resume)(struct platform_device *pdev);
+	int (*uart_getc)(struct platform_device *pdev);
+	void (*uart_putc)(struct platform_device *pdev, unsigned int c);
+	void (*uart_flush)(struct platform_device *pdev);
+	void (*uart_enable)(struct platform_device *pdev);
+	void (*uart_disable)(struct platform_device *pdev);
+
+	int (*uart_dev_suspend)(struct platform_device *pdev);
+	int (*uart_dev_resume)(struct platform_device *pdev);
+
+	void (*fiq_enable)(struct platform_device *pdev, unsigned int fiq,
+								bool enable);
+	void (*fiq_ack)(struct platform_device *pdev, unsigned int fiq);
+
+	void (*force_irq)(struct platform_device *pdev, unsigned int irq);
+	void (*force_irq_ack)(struct platform_device *pdev, unsigned int irq);
+};
+
+#endif