From f2d937f3bf00665ccf048b3b6616ef95859b0945 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 17 Apr 2008 20:05:37 +0200 Subject: [PATCH] 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 Signed-off-by: Ingo Molnar Signed-off-by: Jan Kiszka Reviewed-by: Thomas Gleixner --- drivers/char/tty_io.c | 47 ++++++++++ drivers/serial/8250.c | 58 +++++++++++++ drivers/serial/Kconfig | 3 + drivers/serial/Makefile | 1 + drivers/serial/kgdboc.c | 163 +++++++++++++++++++++++++++++++++++ drivers/serial/serial_core.c | 72 +++++++++++++++- include/linux/serial_core.h | 4 + include/linux/tty_driver.h | 12 +++ 8 files changed, 357 insertions(+), 3 deletions(-) create mode 100644 drivers/serial/kgdboc.c diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 613ec816ce6..4d3c7018f0c 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1155,6 +1155,48 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index) return NULL; } +#ifdef CONFIG_CONSOLE_POLL + +/** + * tty_find_polling_driver - find device of a polled tty + * @name: name string to match + * @line: pointer to resulting tty line nr + * + * This routine returns a tty driver structure, given a name + * and the condition that the tty driver is capable of polled + * operation. + */ +struct tty_driver *tty_find_polling_driver(char *name, int *line) +{ + struct tty_driver *p, *res = NULL; + int tty_line = 0; + char *str; + + mutex_lock(&tty_mutex); + /* Search through the tty devices to look for a match */ + list_for_each_entry(p, &tty_drivers, tty_drivers) { + str = name + strlen(p->name); + tty_line = simple_strtoul(str, &str, 10); + if (*str == ',') + str++; + if (*str == '\0') + str = 0; + + if (tty_line >= 0 && tty_line <= p->num && p->poll_init && + !p->poll_init(p, tty_line, str)) { + + res = p; + *line = tty_line; + break; + } + } + mutex_unlock(&tty_mutex); + + return res; +} +EXPORT_SYMBOL_GPL(tty_find_polling_driver); +#endif + /** * tty_check_change - check for POSIX terminal changes * @tty: tty to check @@ -3850,6 +3892,11 @@ void tty_set_operations(struct tty_driver *driver, driver->write_proc = op->write_proc; driver->tiocmget = op->tiocmget; driver->tiocmset = op->tiocmset; +#ifdef CONFIG_CONSOLE_POLL + driver->poll_init = op->poll_init; + driver->poll_get_char = op->poll_get_char; + driver->poll_put_char = op->poll_put_char; +#endif } diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 77f7a7f0646..96a585e1cee 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 cf627cd1b4c..f7cd9504d81 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 640cfe44a56..3cbea549472 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 00000000000..34183079160 --- /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 + * + * 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 +#include +#include +#include + +#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, "[,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 0f5a17987cc..4d7eecbead9 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 , * 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 }; /** diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 289942fc665..7cb094a8245 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -213,6 +213,10 @@ struct uart_ops { void (*config_port)(struct uart_port *, int); int (*verify_port)(struct uart_port *, struct serial_struct *); int (*ioctl)(struct uart_port *, unsigned int, unsigned long); +#ifdef CONFIG_CONSOLE_POLL + void (*poll_put_char)(struct uart_port *, unsigned char); + int (*poll_get_char)(struct uart_port *); +#endif }; #define UART_CONFIG_TYPE (1 << 0) diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 85c95cd39bc..21f69aca450 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -125,6 +125,7 @@ #include struct tty_struct; +struct tty_driver; struct tty_operations { int (*open)(struct tty_struct * tty, struct file * filp); @@ -157,6 +158,11 @@ struct tty_operations { int (*tiocmget)(struct tty_struct *tty, struct file *file); int (*tiocmset)(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear); +#ifdef CONFIG_CONSOLE_POLL + int (*poll_init)(struct tty_driver *driver, int line, char *options); + int (*poll_get_char)(struct tty_driver *driver, int line); + void (*poll_put_char)(struct tty_driver *driver, int line, char ch); +#endif }; struct tty_driver { @@ -220,6 +226,11 @@ struct tty_driver { int (*tiocmget)(struct tty_struct *tty, struct file *file); int (*tiocmset)(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear); +#ifdef CONFIG_CONSOLE_POLL + int (*poll_init)(struct tty_driver *driver, int line, char *options); + int (*poll_get_char)(struct tty_driver *driver, int line); + void (*poll_put_char)(struct tty_driver *driver, int line, char ch); +#endif struct list_head tty_drivers; }; @@ -230,6 +241,7 @@ struct tty_driver *alloc_tty_driver(int lines); void put_tty_driver(struct tty_driver *driver); void tty_set_operations(struct tty_driver *driver, const struct tty_operations *op); +extern struct tty_driver *tty_find_polling_driver(char *name, int *line); /* tty driver magic number */ #define TTY_DRIVER_MAGIC 0x5402 -- 2.41.0