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authorJason Wessel <jason.wessel@windriver.com>2008-04-17 20:05:37 +0200
committerIngo Molnar <mingo@elte.hu>2008-04-17 20:05:37 +0200
commitf2d937f3bf00665ccf048b3b6616ef95859b0945 (patch)
tree6136ded0706be0d39a09a0a912e8f79a4ab63322 /drivers/serial
parentdc7d552705215ac50a0617fcf51bb9c736255b8e (diff)
downloadop-kernel-dev-f2d937f3bf00665ccf048b3b6616ef95859b0945.zip
op-kernel-dev-f2d937f3bf00665ccf048b3b6616ef95859b0945.tar.gz
consoles: polling support, kgdboc
polled console handling support, to access a console in an irq-less way while in debug or irq context. absolutely zero impact as long as CONFIG_CONSOLE_POLL is disabled. (which is the default) [ jan.kiszka@siemens.com: lots of cleanups ] [ mingo@elte.hu: redesign, splitups, cleanups. ] Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jan Kiszka <jan.kiszka@web.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'drivers/serial')
-rw-r--r--drivers/serial/8250.c58
-rw-r--r--drivers/serial/Kconfig3
-rw-r--r--drivers/serial/Makefile1
-rw-r--r--drivers/serial/kgdboc.c163
-rw-r--r--drivers/serial/serial_core.c72
5 files changed, 294 insertions, 3 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 77f7a7f..96a585e 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1740,6 +1740,60 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits)
}
}
+#ifdef CONFIG_CONSOLE_POLL
+/*
+ * Console polling routines for writing and reading from the uart while
+ * in an interrupt or debug context.
+ */
+
+static int serial8250_get_poll_char(struct uart_port *port)
+{
+ struct uart_8250_port *up = (struct uart_8250_port *)port;
+ unsigned char lsr = serial_inp(up, UART_LSR);
+
+ while (!(lsr & UART_LSR_DR))
+ lsr = serial_inp(up, UART_LSR);
+
+ return serial_inp(up, UART_RX);
+}
+
+
+static void serial8250_put_poll_char(struct uart_port *port,
+ unsigned char c)
+{
+ unsigned int ier;
+ struct uart_8250_port *up = (struct uart_8250_port *)port;
+
+ /*
+ * First save the IER then disable the interrupts
+ */
+ ier = serial_in(up, UART_IER);
+ if (up->capabilities & UART_CAP_UUE)
+ serial_out(up, UART_IER, UART_IER_UUE);
+ else
+ serial_out(up, UART_IER, 0);
+
+ wait_for_xmitr(up, BOTH_EMPTY);
+ /*
+ * Send the character out.
+ * If a LF, also do CR...
+ */
+ serial_out(up, UART_TX, c);
+ if (c == 10) {
+ wait_for_xmitr(up, BOTH_EMPTY);
+ serial_out(up, UART_TX, 13);
+ }
+
+ /*
+ * Finally, wait for transmitter to become empty
+ * and restore the IER
+ */
+ wait_for_xmitr(up, BOTH_EMPTY);
+ serial_out(up, UART_IER, ier);
+}
+
+#endif /* CONFIG_CONSOLE_POLL */
+
static int serial8250_startup(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
@@ -2386,6 +2440,10 @@ static struct uart_ops serial8250_pops = {
.request_port = serial8250_request_port,
.config_port = serial8250_config_port,
.verify_port = serial8250_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+ .poll_get_char = serial8250_get_poll_char,
+ .poll_put_char = serial8250_put_poll_char,
+#endif
};
static struct uart_8250_port serial8250_ports[UART_NR];
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index cf627cd..f7cd950 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -961,6 +961,9 @@ config SERIAL_CORE
config SERIAL_CORE_CONSOLE
bool
+config CONSOLE_POLL
+ bool
+
config SERIAL_68328
bool "68328 serial support"
depends on M68328 || M68EZ328 || M68VZ328
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 640cfe4..3cbea54 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -66,4 +66,5 @@ obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
+obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
obj-$(CONFIG_SERIAL_QE) += ucc_uart.o
diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
new file mode 100644
index 0000000..3418307
--- /dev/null
+++ b/drivers/serial/kgdboc.c
@@ -0,0 +1,163 @@
+/*
+ * Based on the same principle as kgdboe using the NETPOLL api, this
+ * driver uses a console polling api to implement a gdb serial inteface
+ * which is multiplexed on a console port.
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/kernel.h>
+#include <linux/ctype.h>
+#include <linux/kgdb.h>
+#include <linux/tty.h>
+
+#define MAX_CONFIG_LEN 40
+
+static struct kgdb_io kgdboc_io_ops;
+
+/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
+static int configured = -1;
+
+static char config[MAX_CONFIG_LEN];
+static struct kparam_string kps = {
+ .string = config,
+ .maxlen = MAX_CONFIG_LEN,
+};
+
+static struct tty_driver *kgdb_tty_driver;
+static int kgdb_tty_line;
+
+static int kgdboc_option_setup(char *opt)
+{
+ if (strlen(opt) > MAX_CONFIG_LEN) {
+ printk(KERN_ERR "kgdboc: config string too long\n");
+ return -ENOSPC;
+ }
+ strcpy(config, opt);
+
+ return 0;
+}
+
+__setup("kgdboc=", kgdboc_option_setup);
+
+static int configure_kgdboc(void)
+{
+ struct tty_driver *p;
+ int tty_line = 0;
+ int err;
+
+ err = kgdboc_option_setup(config);
+ if (err || !strlen(config) || isspace(config[0]))
+ goto noconfig;
+
+ err = -ENODEV;
+
+ p = tty_find_polling_driver(config, &tty_line);
+ if (!p)
+ goto noconfig;
+
+ kgdb_tty_driver = p;
+ kgdb_tty_line = tty_line;
+
+ err = kgdb_register_io_module(&kgdboc_io_ops);
+ if (err)
+ goto noconfig;
+
+ configured = 1;
+
+ return 0;
+
+noconfig:
+ config[0] = 0;
+ configured = 0;
+
+ return err;
+}
+
+static int __init init_kgdboc(void)
+{
+ /* Already configured? */
+ if (configured == 1)
+ return 0;
+
+ return configure_kgdboc();
+}
+
+static void cleanup_kgdboc(void)
+{
+ if (configured == 1)
+ kgdb_unregister_io_module(&kgdboc_io_ops);
+}
+
+static int kgdboc_get_char(void)
+{
+ return kgdb_tty_driver->poll_get_char(kgdb_tty_driver, kgdb_tty_line);
+}
+
+static void kgdboc_put_char(u8 chr)
+{
+ kgdb_tty_driver->poll_put_char(kgdb_tty_driver, kgdb_tty_line, chr);
+}
+
+static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
+{
+ if (strlen(kmessage) >= MAX_CONFIG_LEN) {
+ printk(KERN_ERR "kgdboc: config string too long\n");
+ return -ENOSPC;
+ }
+
+ /* Only copy in the string if the init function has not run yet */
+ if (configured < 0) {
+ strcpy(config, kmessage);
+ return 0;
+ }
+
+ if (kgdb_connected) {
+ printk(KERN_ERR
+ "kgdboc: Cannot reconfigure while KGDB is connected.\n");
+
+ return -EBUSY;
+ }
+
+ strcpy(config, kmessage);
+
+ if (configured == 1)
+ cleanup_kgdboc();
+
+ /* Go and configure with the new params. */
+ return configure_kgdboc();
+}
+
+static void kgdboc_pre_exp_handler(void)
+{
+ /* Increment the module count when the debugger is active */
+ if (!kgdb_connected)
+ try_module_get(THIS_MODULE);
+}
+
+static void kgdboc_post_exp_handler(void)
+{
+ /* decrement the module count when the debugger detaches */
+ if (!kgdb_connected)
+ module_put(THIS_MODULE);
+}
+
+static struct kgdb_io kgdboc_io_ops = {
+ .name = "kgdboc",
+ .read_char = kgdboc_get_char,
+ .write_char = kgdboc_put_char,
+ .pre_exception = kgdboc_pre_exp_handler,
+ .post_exception = kgdboc_post_exp_handler,
+};
+
+module_init(init_kgdboc);
+module_exit(cleanup_kgdboc);
+module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
+MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
+MODULE_DESCRIPTION("KGDB Console TTY Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 0f5a179..4d7eecb 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1827,7 +1827,7 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co)
* options. The format of the string is <baud><parity><bits><flow>,
* eg: 115200n8r
*/
-void __init
+void
uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
{
char *s = options;
@@ -1842,6 +1842,7 @@ uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
if (*s)
*flow = *s;
}
+EXPORT_SYMBOL_GPL(uart_parse_options);
struct baud_rates {
unsigned int rate;
@@ -1872,7 +1873,7 @@ static const struct baud_rates baud_rates[] = {
* @bits: number of data bits
* @flow: flow control character - 'r' (rts)
*/
-int __init
+int
uart_set_options(struct uart_port *port, struct console *co,
int baud, int parity, int bits, int flow)
{
@@ -1924,10 +1925,16 @@ uart_set_options(struct uart_port *port, struct console *co,
port->mctrl |= TIOCM_DTR;
port->ops->set_termios(port, &termios, &dummy);
- co->cflag = termios.c_cflag;
+ /*
+ * Allow the setting of the UART parameters with a NULL console
+ * too:
+ */
+ if (co)
+ co->cflag = termios.c_cflag;
return 0;
}
+EXPORT_SYMBOL_GPL(uart_set_options);
#endif /* CONFIG_SERIAL_CORE_CONSOLE */
static void uart_change_pm(struct uart_state *state, int pm_state)
@@ -2182,6 +2189,60 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
}
}
+#ifdef CONFIG_CONSOLE_POLL
+
+static int uart_poll_init(struct tty_driver *driver, int line, char *options)
+{
+ struct uart_driver *drv = driver->driver_state;
+ struct uart_state *state = drv->state + line;
+ struct uart_port *port;
+ int baud = 9600;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
+
+ if (!state || !state->port)
+ return -1;
+
+ port = state->port;
+ if (!(port->ops->poll_get_char && port->ops->poll_put_char))
+ return -1;
+
+ if (options) {
+ uart_parse_options(options, &baud, &parity, &bits, &flow);
+ return uart_set_options(port, NULL, baud, parity, bits, flow);
+ }
+
+ return 0;
+}
+
+static int uart_poll_get_char(struct tty_driver *driver, int line)
+{
+ struct uart_driver *drv = driver->driver_state;
+ struct uart_state *state = drv->state + line;
+ struct uart_port *port;
+
+ if (!state || !state->port)
+ return -1;
+
+ port = state->port;
+ return port->ops->poll_get_char(port);
+}
+
+static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
+{
+ struct uart_driver *drv = driver->driver_state;
+ struct uart_state *state = drv->state + line;
+ struct uart_port *port;
+
+ if (!state || !state->port)
+ return;
+
+ port = state->port;
+ port->ops->poll_put_char(port, ch);
+}
+#endif
+
static const struct tty_operations uart_ops = {
.open = uart_open,
.close = uart_close,
@@ -2206,6 +2267,11 @@ static const struct tty_operations uart_ops = {
#endif
.tiocmget = uart_tiocmget,
.tiocmset = uart_tiocmset,
+#ifdef CONFIG_CONSOLE_POLL
+ .poll_init = uart_poll_init,
+ .poll_get_char = uart_poll_get_char,
+ .poll_put_char = uart_poll_put_char,
+#endif
};
/**
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