diff options
Diffstat (limited to 'include/linux/serial_core.h')
| -rw-r--r-- | include/linux/serial_core.h | 369 |
1 files changed, 351 insertions, 18 deletions
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 657a0fc68a3f..aef3145f2032 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -31,9 +31,336 @@ struct serial_struct; struct device; struct gpio_desc; -/* +/** + * struct uart_ops -- interface between serial_core and the driver + * * This structure describes all the operations that can be done on the - * physical hardware. See Documentation/driver-api/serial/driver.rst for details. + * physical hardware. + * + * @tx_empty: ``unsigned int ()(struct uart_port *port)`` + * + * This function tests whether the transmitter fifo and shifter for the + * @port is empty. If it is empty, this function should return + * %TIOCSER_TEMT, otherwise return 0. If the port does not support this + * operation, then it should return %TIOCSER_TEMT. + * + * Locking: none. + * Interrupts: caller dependent. + * This call must not sleep + * + * @set_mctrl: ``void ()(struct uart_port *port, unsigned int mctrl)`` + * + * This function sets the modem control lines for @port to the state + * described by @mctrl. The relevant bits of @mctrl are: + * + * - %TIOCM_RTS RTS signal. + * - %TIOCM_DTR DTR signal. + * - %TIOCM_OUT1 OUT1 signal. + * - %TIOCM_OUT2 OUT2 signal. + * - %TIOCM_LOOP Set the port into loopback mode. + * + * If the appropriate bit is set, the signal should be driven + * active. If the bit is clear, the signal should be driven + * inactive. + * + * Locking: @port->lock taken. + * Interrupts: locally disabled. + * This call must not sleep + * + * @get_mctrl: ``unsigned int ()(struct uart_port *port)`` + * + * Returns the current state of modem control inputs of @port. The state + * of the outputs should not be returned, since the core keeps track of + * their state. The state information should include: + * + * - %TIOCM_CAR state of DCD signal + * - %TIOCM_CTS state of CTS signal + * - %TIOCM_DSR state of DSR signal + * - %TIOCM_RI state of RI signal + * + * The bit is set if the signal is currently driven active. If + * the port does not support CTS, DCD or DSR, the driver should + * indicate that the signal is permanently active. If RI is + * not available, the signal should not be indicated as active. + * + * Locking: @port->lock taken. + * Interrupts: locally disabled. + * This call must not sleep + * + * @stop_tx: ``void ()(struct uart_port *port)`` + * + * Stop transmitting characters. This might be due to the CTS line + * becoming inactive or the tty layer indicating we want to stop + * transmission due to an %XOFF character. + * + * The driver should stop transmitting characters as soon as possible. + * + * Locking: @port->lock taken. + * Interrupts: locally disabled. + * This call must not sleep + * + * @start_tx: ``void ()(struct uart_port *port)`` + * + * Start transmitting characters. + * + * Locking: @port->lock taken. + * Interrupts: locally disabled. + * This call must not sleep + * + * @throttle: ``void ()(struct uart_port *port)`` + * + * Notify the serial driver that input buffers for the line discipline are + * close to full, and it should somehow signal that no more characters + * should be sent to the serial port. + * This will be called only if hardware assisted flow control is enabled. + * + * Locking: serialized with @unthrottle() and termios modification by the + * tty layer. + * + * @unthrottle: ``void ()(struct uart_port *port)`` + * + * Notify the serial driver that characters can now be sent to the serial + * port without fear of overrunning the input buffers of the line + * disciplines. + * + * This will be called only if hardware assisted flow control is enabled. + * + * Locking: serialized with @throttle() and termios modification by the + * tty layer. + * + * @send_xchar: ``void ()(struct uart_port *port, char ch)`` + * + * Transmit a high priority character, even if the port is stopped. This + * is used to implement XON/XOFF flow control and tcflow(). If the serial + * driver does not implement this function, the tty core will append the + * character to the circular buffer and then call start_tx() / stop_tx() + * to flush the data out. + * + * Do not transmit if @ch == '\0' (%__DISABLED_CHAR). + * + * Locking: none. + * Interrupts: caller dependent. + * + * @stop_rx: ``void ()(struct uart_port *port)`` + * + * Stop receiving characters; the @port is in the process of being closed. + * + * Locking: @port->lock taken. + * Interrupts: locally disabled. + * This call must not sleep + * + * @enable_ms: ``void ()(struct uart_port *port)`` + * + * Enable the modem status interrupts. + * + * This method may be called multiple times. Modem status interrupts + * should be disabled when the @shutdown() method is called. + * + * Locking: @port->lock taken. + * Interrupts: locally disabled. + * This call must not sleep + * + * @break_ctl: ``void ()(struct uart_port *port, int ctl)`` + * + * Control the transmission of a break signal. If @ctl is nonzero, the + * break signal should be transmitted. The signal should be terminated + * when another call is made with a zero @ctl. + * + * Locking: caller holds tty_port->mutex + * + * @startup: ``int ()(struct uart_port *port)`` + * + * Grab any interrupt resources and initialise any low level driver state. + * Enable the port for reception. It should not activate RTS nor DTR; + * this will be done via a separate call to @set_mctrl(). + * + * This method will only be called when the port is initially opened. + * + * Locking: port_sem taken. + * Interrupts: globally disabled. + * + * @shutdown: ``void ()(struct uart_port *port)`` + * + * Disable the @port, disable any break condition that may be in effect, + * and free any interrupt resources. It should not disable RTS nor DTR; + * this will have already been done via a separate call to @set_mctrl(). + * + * Drivers must not access @port->state once this call has completed. + * + * This method will only be called when there are no more users of this + * @port. + * + * Locking: port_sem taken. + * Interrupts: caller dependent. + * + * @flush_buffer: ``void ()(struct uart_port *port)`` + * + * Flush any write buffers, reset any DMA state and stop any ongoing DMA + * transfers. + * + * This will be called whenever the @port->state->xmit circular buffer is + * cleared. + * + * Locking: @port->lock taken. + * Interrupts: locally disabled. + * This call must not sleep + * + * @set_termios: ``void ()(struct uart_port *port, struct ktermios *new, + * struct ktermios *old)`` + * + * Change the @port parameters, including word length, parity, stop bits. + * Update @port->read_status_mask and @port->ignore_status_mask to + * indicate the types of events we are interested in receiving. Relevant + * ktermios::c_cflag bits are: + * + * - %CSIZE - word size + * - %CSTOPB - 2 stop bits + * - %PARENB - parity enable + * - %PARODD - odd parity (when %PARENB is in force) + * - %ADDRB - address bit (changed through uart_port::rs485_config()). + * - %CREAD - enable reception of characters (if not set, still receive + * characters from the port, but throw them away). + * - %CRTSCTS - if set, enable CTS status change reporting. + * - %CLOCAL - if not set, enable modem status change reporting. + * + * Relevant ktermios::c_iflag bits are: + * + * - %INPCK - enable frame and parity error events to be passed to the TTY + * layer. + * - %BRKINT / %PARMRK - both of these enable break events to be passed to + * the TTY layer. + * - %IGNPAR - ignore parity and framing errors. + * - %IGNBRK - ignore break errors. If %IGNPAR is also set, ignore overrun + * errors as well. + * + * The interaction of the ktermios::c_iflag bits is as follows (parity + * error given as an example): + * + * ============ ======= ======= ========================================= + * Parity error INPCK IGNPAR + * ============ ======= ======= ========================================= + * n/a 0 n/a character received, marked as %TTY_NORMAL + * None 1 n/a character received, marked as %TTY_NORMAL + * Yes 1 0 character received, marked as %TTY_PARITY + * Yes 1 1 character discarded + * ============ ======= ======= ========================================= + * + * Other flags may be used (eg, xon/xoff characters) if your hardware + * supports hardware "soft" flow control. + * + * Locking: caller holds tty_port->mutex + * Interrupts: caller dependent. + * This call must not sleep + * + * @set_ldisc: ``void ()(struct uart_port *port, struct ktermios *termios)`` + * + * Notifier for discipline change. See + * Documentation/driver-api/tty/tty_ldisc.rst. + * + * Locking: caller holds tty_port->mutex + * + * @pm: ``void ()(struct uart_port *port, unsigned int state, + * unsigned int oldstate)`` + * + * Perform any power management related activities on the specified @port. + * @state indicates the new state (defined by enum uart_pm_state), + * @oldstate indicates the previous state. + * + * This function should not be used to grab any resources. + * + * This will be called when the @port is initially opened and finally + * closed, except when the @port is also the system console. This will + * occur even if %CONFIG_PM is not set. + * + * Locking: none. + * Interrupts: caller dependent. + * + * @type: ``const char *()(struct uart_port *port)`` + * + * Return a pointer to a string constant describing the specified @port, + * or return %NULL, in which case the string 'unknown' is substituted. + * + * Locking: none. + * Interrupts: caller dependent. + * + * @release_port: ``void ()(struct uart_port *port)`` + * + * Release any memory and IO region resources currently in use by the + * @port. + * + * Locking: none. + * Interrupts: caller dependent. + * + * @request_port: ``int ()(struct uart_port *port)`` + * + * Request any memory and IO region resources required by the port. If any + * fail, no resources should be registered when this function returns, and + * it should return -%EBUSY on failure. + * + * Locking: none. + * Interrupts: caller dependent. + * + * @config_port: ``void ()(struct uart_port *port, int type)`` + * + * Perform any autoconfiguration steps required for the @port. @type + * contains a bit mask of the required configuration. %UART_CONFIG_TYPE + * indicates that the port requires detection and identification. + * @port->type should be set to the type found, or %PORT_UNKNOWN if no + * port was detected. + * + * %UART_CONFIG_IRQ indicates autoconfiguration of the interrupt signal, + * which should be probed using standard kernel autoprobing techniques. + * This is not necessary on platforms where ports have interrupts + * internally hard wired (eg, system on a chip implementations). + * + * Locking: none. + * Interrupts: caller dependent. + * + * @verify_port: ``int ()(struct uart_port *port, + * struct serial_struct *serinfo)`` + * + * Verify the new serial port information contained within @serinfo is + * suitable for this port type. + * + * Locking: none. + * Interrupts: caller dependent. + * + * @ioctl: ``int ()(struct uart_port *port, unsigned int cmd, + * unsigned long arg)`` + * + * Perform any port specific IOCTLs. IOCTL commands must be defined using + * the standard numbering system found in <asm/ioctl.h>. + * + * Locking: none. + * Interrupts: caller dependent. + * + * @poll_init: ``int ()(struct uart_port *port)`` + * + * Called by kgdb to perform the minimal hardware initialization needed to + * support @poll_put_char() and @poll_get_char(). Unlike @startup(), this + * should not request interrupts. + * + * Locking: %tty_mutex and tty_port->mutex taken. + * Interrupts: n/a. + * + * @poll_put_char: ``void ()(struct uart_port *port, unsigned char ch)`` + * + * Called by kgdb to write a single character @ch directly to the serial + * @port. It can and should block until there is space in the TX FIFO. + * + * Locking: none. + * Interrupts: caller dependent. + * This call must not sleep + * + * @poll_get_char: ``int ()(struct uart_port *port)`` + * + * Called by kgdb to read a single character directly from the serial + * port. If data is available, it should be returned; otherwise the + * function should return %NO_POLL_CHAR immediately. + * + * Locking: none. + * Interrupts: caller dependent. + * This call must not sleep */ struct uart_ops { unsigned int (*tx_empty)(struct uart_port *); @@ -56,22 +383,8 @@ struct uart_ops { void (*set_ldisc)(struct uart_port *, struct ktermios *); void (*pm)(struct uart_port *, unsigned int state, unsigned int oldstate); - - /* - * Return a string describing the type of the port - */ const char *(*type)(struct uart_port *); - - /* - * Release IO and memory resources used by the port. - * This includes iounmap if necessary. - */ void (*release_port)(struct uart_port *); - - /* - * Request IO and memory resources used by the port. - * This includes iomapping the port if necessary. - */ int (*request_port)(struct uart_port *); void (*config_port)(struct uart_port *, int); int (*verify_port)(struct uart_port *, struct serial_struct *); @@ -133,6 +446,7 @@ struct uart_port { unsigned int old); void (*handle_break)(struct uart_port *); int (*rs485_config)(struct uart_port *, + struct ktermios *termios, struct serial_rs485 *rs485); int (*iso7816_config)(struct uart_port *, struct serial_iso7816 *iso7816); @@ -232,7 +546,6 @@ struct uart_port { int hw_stopped; /* sw-assisted CTS flow state */ unsigned int mctrl; /* current modem ctrl settings */ - unsigned int timeout; /* character-based timeout */ unsigned int frame_time; /* frame timing in ns */ unsigned int type; /* port type */ const struct uart_ops *ops; @@ -255,6 +568,7 @@ struct uart_port { struct attribute_group *attr_group; /* port specific attributes */ const struct attribute_group **tty_groups; /* all attributes (serial core use only) */ struct serial_rs485 rs485; + struct serial_rs485 rs485_supported; /* Supported mask for serial_rs485 */ struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */ struct serial_iso7816 iso7816; void *private_data; /* generic platform data pointer */ @@ -334,10 +648,23 @@ unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios unsigned int max); unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud); +/* + * Calculates FIFO drain time. + */ +static inline unsigned long uart_fifo_timeout(struct uart_port *port) +{ + u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize; + + /* Add .02 seconds of slop */ + fifo_timeout += 20 * NSEC_PER_MSEC; + + return max(nsecs_to_jiffies(fifo_timeout), 1UL); +} + /* Base timer interval for polling */ static inline int uart_poll_timeout(struct uart_port *port) { - int timeout = port->timeout; + int timeout = uart_fifo_timeout(port); return timeout > 6 ? (timeout / 2 - 2) : 1; } @@ -390,6 +717,11 @@ static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED; static inline int setup_earlycon(char *buf) { return 0; } #endif +static inline bool uart_console_enabled(struct uart_port *port) +{ + return uart_console(port) && (port->cons->flags & CON_ENABLED); +} + struct uart_port *uart_get_console(struct uart_port *ports, int nr, struct console *c); int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr, @@ -593,4 +925,5 @@ static inline int uart_handle_break(struct uart_port *port) !((cflag) & CLOCAL)) int uart_get_rs485_mode(struct uart_port *port); +int uart_rs485_config(struct uart_port *port); #endif /* LINUX_SERIAL_CORE_H */ |