ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/drivers/tty/serial/kgdb_nmi.c b/marvell/linux/drivers/tty/serial/kgdb_nmi.c
new file mode 100644
index 0000000..4029272
--- /dev/null
+++ b/marvell/linux/drivers/tty/serial/kgdb_nmi.c
@@ -0,0 +1,383 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KGDB NMI serial console
+ *
+ * Copyright 2010 Google, Inc.
+ * Arve Hjønnevåg <arve@android.com>
+ * Colin Cross <ccross@android.com>
+ * Copyright 2012 Linaro Ltd.
+ * Anton Vorontsov <anton.vorontsov@linaro.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/compiler.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/atomic.h>
+#include <linux/console.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/serial_core.h>
+#include <linux/interrupt.h>
+#include <linux/hrtimer.h>
+#include <linux/tick.h>
+#include <linux/kfifo.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+
+static int kgdb_nmi_knock = 1;
+module_param_named(knock, kgdb_nmi_knock, int, 0600);
+MODULE_PARM_DESC(knock, "if set to 1 (default), the special '$3#33' command " \
+ "must be used to enter the debugger; when set to 0, " \
+ "hitting return key is enough to enter the debugger; " \
+ "when set to -1, the debugger is entered immediately " \
+ "upon NMI");
+
+static char *kgdb_nmi_magic = "$3#33";
+module_param_named(magic, kgdb_nmi_magic, charp, 0600);
+MODULE_PARM_DESC(magic, "magic sequence to enter NMI debugger (default $3#33)");
+
+static atomic_t kgdb_nmi_num_readers = ATOMIC_INIT(0);
+
+static int kgdb_nmi_console_setup(struct console *co, char *options)
+{
+ arch_kgdb_ops.enable_nmi(1);
+
+ /* The NMI console uses the dbg_io_ops to issue console messages. To
+ * avoid duplicate messages during kdb sessions we must inform kdb's
+ * I/O utilities that messages sent to the console will automatically
+ * be displayed on the dbg_io.
+ */
+ dbg_io_ops->is_console = true;
+
+ return 0;
+}
+
+static void kgdb_nmi_console_write(struct console *co, const char *s, uint c)
+{
+ int i;
+
+ for (i = 0; i < c; i++)
+ dbg_io_ops->write_char(s[i]);
+}
+
+static struct tty_driver *kgdb_nmi_tty_driver;
+
+static struct tty_driver *kgdb_nmi_console_device(struct console *co, int *idx)
+{
+ *idx = co->index;
+ return kgdb_nmi_tty_driver;
+}
+
+static struct console kgdb_nmi_console = {
+ .name = "ttyNMI",
+ .setup = kgdb_nmi_console_setup,
+ .write = kgdb_nmi_console_write,
+ .device = kgdb_nmi_console_device,
+ .flags = CON_PRINTBUFFER | CON_ANYTIME,
+ .index = -1,
+};
+
+/*
+ * This is usually the maximum rate on debug ports. We make fifo large enough
+ * to make copy-pasting to the terminal usable.
+ */
+#define KGDB_NMI_BAUD 115200
+#define KGDB_NMI_FIFO_SIZE roundup_pow_of_two(KGDB_NMI_BAUD / 8 / HZ)
+
+struct kgdb_nmi_tty_priv {
+ struct tty_port port;
+ struct timer_list timer;
+ STRUCT_KFIFO(char, KGDB_NMI_FIFO_SIZE) fifo;
+};
+
+static struct tty_port *kgdb_nmi_port;
+
+static void kgdb_tty_recv(int ch)
+{
+ struct kgdb_nmi_tty_priv *priv;
+ char c = ch;
+
+ if (!kgdb_nmi_port || ch < 0)
+ return;
+ /*
+ * Can't use port->tty->driver_data as tty might be not there. Timer
+ * will check for tty and will get the ref, but here we don't have to
+ * do that, and actually, we can't: we're in NMI context, no locks are
+ * possible.
+ */
+ priv = container_of(kgdb_nmi_port, struct kgdb_nmi_tty_priv, port);
+ kfifo_in(&priv->fifo, &c, 1);
+}
+
+static int kgdb_nmi_poll_one_knock(void)
+{
+ static int n;
+ int c = -1;
+ const char *magic = kgdb_nmi_magic;
+ size_t m = strlen(magic);
+ bool printch = 0;
+
+ c = dbg_io_ops->read_char();
+ if (c == NO_POLL_CHAR)
+ return c;
+
+ if (!kgdb_nmi_knock && (c == '\r' || c == '\n')) {
+ return 1;
+ } else if (c == magic[n]) {
+ n = (n + 1) % m;
+ if (!n)
+ return 1;
+ printch = 1;
+ } else {
+ n = 0;
+ }
+
+ if (atomic_read(&kgdb_nmi_num_readers)) {
+ kgdb_tty_recv(c);
+ return 0;
+ }
+
+ if (printch) {
+ kdb_printf("%c", c);
+ return 0;
+ }
+
+ kdb_printf("\r%s %s to enter the debugger> %*s",
+ kgdb_nmi_knock ? "Type" : "Hit",
+ kgdb_nmi_knock ? magic : "<return>", (int)m, "");
+ while (m--)
+ kdb_printf("\b");
+ return 0;
+}
+
+/**
+ * kgdb_nmi_poll_knock - Check if it is time to enter the debugger
+ *
+ * "Serial ports are often noisy, especially when muxed over another port (we
+ * often use serial over the headset connector). Noise on the async command
+ * line just causes characters that are ignored, on a command line that blocked
+ * execution noise would be catastrophic." -- Colin Cross
+ *
+ * So, this function implements KGDB/KDB knocking on the serial line: we won't
+ * enter the debugger until we receive a known magic phrase (which is actually
+ * "$3#33", known as "escape to KDB" command. There is also a relaxed variant
+ * of knocking, i.e. just pressing the return key is enough to enter the
+ * debugger. And if knocking is disabled, the function always returns 1.
+ */
+bool kgdb_nmi_poll_knock(void)
+{
+ if (kgdb_nmi_knock < 0)
+ return true;
+
+ while (1) {
+ int ret;
+
+ ret = kgdb_nmi_poll_one_knock();
+ if (ret == NO_POLL_CHAR)
+ return false;
+ else if (ret == 1)
+ break;
+ }
+ return true;
+}
+
+/*
+ * The tasklet is cheap, it does not cause wakeups when reschedules itself,
+ * instead it waits for the next tick.
+ */
+static void kgdb_nmi_tty_receiver(struct timer_list *t)
+{
+ struct kgdb_nmi_tty_priv *priv = from_timer(priv, t, timer);
+ char ch;
+
+ priv->timer.expires = jiffies + (HZ/100);
+ add_timer(&priv->timer);
+
+ if (likely(!atomic_read(&kgdb_nmi_num_readers) ||
+ !kfifo_len(&priv->fifo)))
+ return;
+
+ while (kfifo_out(&priv->fifo, &ch, 1))
+ tty_insert_flip_char(&priv->port, ch, TTY_NORMAL);
+ tty_flip_buffer_push(&priv->port);
+}
+
+static int kgdb_nmi_tty_activate(struct tty_port *port, struct tty_struct *tty)
+{
+ struct kgdb_nmi_tty_priv *priv =
+ container_of(port, struct kgdb_nmi_tty_priv, port);
+
+ kgdb_nmi_port = port;
+ priv->timer.expires = jiffies + (HZ/100);
+ add_timer(&priv->timer);
+
+ return 0;
+}
+
+static void kgdb_nmi_tty_shutdown(struct tty_port *port)
+{
+ struct kgdb_nmi_tty_priv *priv =
+ container_of(port, struct kgdb_nmi_tty_priv, port);
+
+ del_timer(&priv->timer);
+ kgdb_nmi_port = NULL;
+}
+
+static const struct tty_port_operations kgdb_nmi_tty_port_ops = {
+ .activate = kgdb_nmi_tty_activate,
+ .shutdown = kgdb_nmi_tty_shutdown,
+};
+
+static int kgdb_nmi_tty_install(struct tty_driver *drv, struct tty_struct *tty)
+{
+ struct kgdb_nmi_tty_priv *priv;
+ int ret;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ INIT_KFIFO(priv->fifo);
+ timer_setup(&priv->timer, kgdb_nmi_tty_receiver, 0);
+ tty_port_init(&priv->port);
+ priv->port.ops = &kgdb_nmi_tty_port_ops;
+ tty->driver_data = priv;
+
+ ret = tty_port_install(&priv->port, drv, tty);
+ if (ret) {
+ pr_err("%s: can't install tty port: %d\n", __func__, ret);
+ goto err;
+ }
+ return 0;
+err:
+ tty_port_destroy(&priv->port);
+ kfree(priv);
+ return ret;
+}
+
+static void kgdb_nmi_tty_cleanup(struct tty_struct *tty)
+{
+ struct kgdb_nmi_tty_priv *priv = tty->driver_data;
+
+ tty->driver_data = NULL;
+ tty_port_destroy(&priv->port);
+ kfree(priv);
+}
+
+static int kgdb_nmi_tty_open(struct tty_struct *tty, struct file *file)
+{
+ struct kgdb_nmi_tty_priv *priv = tty->driver_data;
+ unsigned int mode = file->f_flags & O_ACCMODE;
+ int ret;
+
+ ret = tty_port_open(&priv->port, tty, file);
+ if (!ret && (mode == O_RDONLY || mode == O_RDWR))
+ atomic_inc(&kgdb_nmi_num_readers);
+
+ return ret;
+}
+
+static void kgdb_nmi_tty_close(struct tty_struct *tty, struct file *file)
+{
+ struct kgdb_nmi_tty_priv *priv = tty->driver_data;
+ unsigned int mode = file->f_flags & O_ACCMODE;
+
+ if (mode == O_RDONLY || mode == O_RDWR)
+ atomic_dec(&kgdb_nmi_num_readers);
+
+ tty_port_close(&priv->port, tty, file);
+}
+
+static void kgdb_nmi_tty_hangup(struct tty_struct *tty)
+{
+ struct kgdb_nmi_tty_priv *priv = tty->driver_data;
+
+ tty_port_hangup(&priv->port);
+}
+
+static int kgdb_nmi_tty_write_room(struct tty_struct *tty)
+{
+ /* Actually, we can handle any amount as we use polled writes. */
+ return 2048;
+}
+
+static int kgdb_nmi_tty_write(struct tty_struct *tty, const unchar *buf, int c)
+{
+ int i;
+
+ for (i = 0; i < c; i++)
+ dbg_io_ops->write_char(buf[i]);
+ return c;
+}
+
+static const struct tty_operations kgdb_nmi_tty_ops = {
+ .open = kgdb_nmi_tty_open,
+ .close = kgdb_nmi_tty_close,
+ .install = kgdb_nmi_tty_install,
+ .cleanup = kgdb_nmi_tty_cleanup,
+ .hangup = kgdb_nmi_tty_hangup,
+ .write_room = kgdb_nmi_tty_write_room,
+ .write = kgdb_nmi_tty_write,
+};
+
+int kgdb_register_nmi_console(void)
+{
+ int ret;
+
+ if (!arch_kgdb_ops.enable_nmi)
+ return 0;
+
+ kgdb_nmi_tty_driver = alloc_tty_driver(1);
+ if (!kgdb_nmi_tty_driver) {
+ pr_err("%s: cannot allocate tty\n", __func__);
+ return -ENOMEM;
+ }
+ kgdb_nmi_tty_driver->driver_name = "ttyNMI";
+ kgdb_nmi_tty_driver->name = "ttyNMI";
+ kgdb_nmi_tty_driver->num = 1;
+ kgdb_nmi_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
+ kgdb_nmi_tty_driver->subtype = SERIAL_TYPE_NORMAL;
+ kgdb_nmi_tty_driver->flags = TTY_DRIVER_REAL_RAW;
+ kgdb_nmi_tty_driver->init_termios = tty_std_termios;
+ tty_termios_encode_baud_rate(&kgdb_nmi_tty_driver->init_termios,
+ KGDB_NMI_BAUD, KGDB_NMI_BAUD);
+ tty_set_operations(kgdb_nmi_tty_driver, &kgdb_nmi_tty_ops);
+
+ ret = tty_register_driver(kgdb_nmi_tty_driver);
+ if (ret) {
+ pr_err("%s: can't register tty driver: %d\n", __func__, ret);
+ goto err_drv_reg;
+ }
+
+ register_console(&kgdb_nmi_console);
+
+ return 0;
+err_drv_reg:
+ put_tty_driver(kgdb_nmi_tty_driver);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kgdb_register_nmi_console);
+
+int kgdb_unregister_nmi_console(void)
+{
+ int ret;
+
+ if (!arch_kgdb_ops.enable_nmi)
+ return 0;
+ arch_kgdb_ops.enable_nmi(0);
+
+ ret = unregister_console(&kgdb_nmi_console);
+ if (ret)
+ return ret;
+
+ ret = tty_unregister_driver(kgdb_nmi_tty_driver);
+ if (ret)
+ return ret;
+ put_tty_driver(kgdb_nmi_tty_driver);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kgdb_unregister_nmi_console);