/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * linux/drivers/char/serial_core.h * * Copyright (C) 2000 Deep Blue Solutions Ltd. */ #ifndef LINUX_SERIAL_CORE_H #define LINUX_SERIAL_CORE_H #include <linux/bitops.h> #include <linux/compiler.h> #include <linux/console.h> #include <linux/interrupt.h> #include <linux/lockdep.h> #include <linux/printk.h> #include <linux/spinlock.h> #include <linux/sched.h> #include <linux/tty.h> #include <linux/mutex.h> #include <linux/sysrq.h> #include <uapi/linux/serial_core.h> #ifdef CONFIG_SERIAL_CORE_CONSOLE #define uart_console(port) \ ((port)->cons && (port)->cons->index == (port)->line) #else #define uart_console(port) ({ (void)port; 0; }) #endif struct uart_port; struct serial_struct; struct serial_port_device; 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. * * @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. * * @start_rx: ``void ()(struct uart_port *port)`` * * Start receiving characters. * * Locking: @port->lock taken. * Interrupts: locally disabled. * This call must not sleep * * @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 *); void (*set_mctrl)(struct uart_port *, unsigned int mctrl); unsigned int (*get_mctrl)(struct uart_port *); void (*stop_tx)(struct uart_port *); void (*start_tx)(struct uart_port *); void (*throttle)(struct uart_port *); void (*unthrottle)(struct uart_port *); void (*send_xchar)(struct uart_port *, char ch); void (*stop_rx)(struct uart_port *); void (*start_rx)(struct uart_port *); void (*enable_ms)(struct uart_port *); void (*break_ctl)(struct uart_port *, int ctl); int (*startup)(struct uart_port *); void (*shutdown)(struct uart_port *); void (*flush_buffer)(struct uart_port *); void (*set_termios)(struct uart_port *, struct ktermios *new, const struct ktermios *old); void (*set_ldisc)(struct uart_port *, struct ktermios *); void (*pm)(struct uart_port *, unsigned int state, unsigned int oldstate); const char *(*type)(struct uart_port *); void (*release_port)(struct uart_port *); int (*request_port)(struct uart_port *); 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 int (*poll_init)(struct uart_port *); void (*poll_put_char)(struct uart_port *, unsigned char); int (*poll_get_char)(struct uart_port *); #endif }; #define NO_POLL_CHAR 0x00ff0000 #define UART_CONFIG_TYPE (1 << 0) #define UART_CONFIG_IRQ (1 << 1) struct uart_icount { __u32 cts; __u32 dsr; __u32 rng; __u32 dcd; __u32 rx; __u32 tx; __u32 frame; __u32 overrun; __u32 parity; __u32 brk; __u32 buf_overrun; }; typedef u64 __bitwise upf_t; typedef unsigned int __bitwise upstat_t; enum uart_iotype { UPIO_UNKNOWN = -1, UPIO_PORT = SERIAL_IO_PORT, /* 8b I/O port access */ UPIO_HUB6 = SERIAL_IO_HUB6, /* Hub6 ISA card */ UPIO_MEM = SERIAL_IO_MEM, /* driver-specific */ UPIO_MEM32 = SERIAL_IO_MEM32, /* 32b little endian */ UPIO_AU = SERIAL_IO_AU, /* Au1x00 and RT288x type IO */ UPIO_TSI = SERIAL_IO_TSI, /* Tsi108/109 type IO */ UPIO_MEM32BE = SERIAL_IO_MEM32BE, /* 32b big endian */ UPIO_MEM16 = SERIAL_IO_MEM16, /* 16b little endian */ }; struct uart_port { spinlock_t lock; /* port lock */ unsigned long iobase; /* in/out[bwl] */ unsigned char __iomem *membase; /* read/write[bwl] */ u32 (*serial_in)(struct uart_port *, unsigned int offset); void (*serial_out)(struct uart_port *, unsigned int offset, u32 val); void (*set_termios)(struct uart_port *, struct ktermios *new, const struct ktermios *old); void (*set_ldisc)(struct uart_port *, struct ktermios *); unsigned int (*get_mctrl)(struct uart_port *); void (*set_mctrl)(struct uart_port *, unsigned int); unsigned int (*get_divisor)(struct uart_port *, unsigned int baud, unsigned int *frac); void (*set_divisor)(struct uart_port *, unsigned int baud, unsigned int quot, unsigned int quot_frac); int (*startup)(struct uart_port *port); void (*shutdown)(struct uart_port *port); void (*throttle)(struct uart_port *port); void (*unthrottle)(struct uart_port *port); int (*handle_irq)(struct uart_port *); void (*pm)(struct uart_port *, unsigned int state, 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); unsigned int ctrl_id; /* optional serial core controller id */ unsigned int port_id; /* optional serial core port id */ unsigned int irq; /* irq number */ unsigned long irqflags; /* irq flags */ unsigned int uartclk; /* base uart clock */ unsigned int fifosize; /* tx fifo size */ unsigned char x_char; /* xon/xoff char */ unsigned char regshift; /* reg offset shift */ unsigned char quirks; /* internal quirks */ /* internal quirks must be updated while holding port mutex */ #define UPQ_NO_TXEN_TEST BIT(0) enum uart_iotype iotype; /* io access style */ unsigned int read_status_mask; /* driver specific */ unsigned int ignore_status_mask; /* driver specific */ struct uart_state *state; /* pointer to parent state */ struct uart_icount icount; /* statistics */ struct console *cons; /* struct console, if any */ /* flags must be updated while holding port mutex */ upf_t flags; /* * These flags must be equivalent to the flags defined in * include/uapi/linux/tty_flags.h which are the userspace definitions * assigned from the serial_struct flags in uart_set_info() * [for bit definitions in the UPF_CHANGE_MASK] * * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable * The remaining bits are serial-core specific and not modifiable by * userspace. */ #ifdef CONFIG_HAS_IOPORT #define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ ) #else #define UPF_FOURPORT 0 #endif #define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ ) #define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ ) #define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ ) #define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ ) #define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ ) #define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ ) #define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ ) #define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ ) #define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ ) #define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ ) #define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ ) #define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ ) #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ ) #define UPF_NO_THRE_TEST ((__force upf_t) BIT_ULL(19)) /* Port has hardware-assisted h/w flow control */ #define UPF_AUTO_CTS ((__force upf_t) BIT_ULL(20)) #define UPF_AUTO_RTS ((__force upf_t) BIT_ULL(21)) #define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS)) /* Port has hardware-assisted s/w flow control */ #define UPF_SOFT_FLOW ((__force upf_t) BIT_ULL(22)) #define UPF_CONS_FLOW ((__force upf_t) BIT_ULL(23)) #define UPF_SHARE_IRQ ((__force upf_t) BIT_ULL(24)) #define UPF_EXAR_EFR ((__force upf_t) BIT_ULL(25)) #define UPF_BUG_THRE ((__force upf_t) BIT_ULL(26)) /* The exact UART type is known and should not be probed. */ #define UPF_FIXED_TYPE ((__force upf_t) BIT_ULL(27)) #define UPF_BOOT_AUTOCONF ((__force upf_t) BIT_ULL(28)) #define UPF_FIXED_PORT ((__force upf_t) BIT_ULL(29)) #define UPF_DEAD ((__force upf_t) BIT_ULL(30)) #define UPF_IOREMAP ((__force upf_t) BIT_ULL(31)) #define UPF_FULL_PROBE ((__force upf_t) BIT_ULL(32)) #define __UPF_CHANGE_MASK 0x17fff #define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK) #define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY)) #if __UPF_CHANGE_MASK > ASYNC_FLAGS #error Change mask not equivalent to userspace-visible bit defines #endif /* * Must hold termios_rwsem, port mutex and port lock to change; * can hold any one lock to read. */ upstat_t status; #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0)) #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1)) #define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2)) #define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3)) #define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4)) #define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5)) bool hw_stopped; /* sw-assisted CTS flow state */ unsigned int mctrl; /* current modem ctrl settings */ unsigned int frame_time; /* frame timing in ns */ unsigned int type; /* port type */ const struct uart_ops *ops; unsigned int custom_divisor; unsigned int line; /* port index */ unsigned int minor; resource_size_t mapbase; /* for ioremap */ resource_size_t mapsize; struct device *dev; /* serial port physical parent device */ struct serial_port_device *port_dev; /* serial core port device */ unsigned long sysrq; /* sysrq timeout */ u8 sysrq_ch; /* char for sysrq */ unsigned char has_sysrq; unsigned char sysrq_seq; /* index in sysrq_toggle_seq */ unsigned char hub6; /* this should be in the 8250 driver */ unsigned char suspended; unsigned char console_reinit; const char *name; /* port name */ 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 gpio_desc *rs485_rx_during_tx_gpio; /* Output GPIO that sets the state of RS485 RX during TX */ struct serial_iso7816 iso7816; void *private_data; /* generic platform data pointer */ }; /* * Only for console->device_lock()/_unlock() callbacks and internal * port lock wrapper synchronization. */ static inline void __uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags) { spin_lock_irqsave(&up->lock, *flags); } /* * Only for console->device_lock()/_unlock() callbacks and internal * port lock wrapper synchronization. */ static inline void __uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags) { spin_unlock_irqrestore(&up->lock, flags); } /** * uart_port_set_cons - Safely set the @cons field for a uart * @up: The uart port to set * @con: The new console to set to * * This function must be used to set @up->cons. It uses the port lock to * synchronize with the port lock wrappers in order to ensure that the console * cannot change or disappear while another context is holding the port lock. */ static inline void uart_port_set_cons(struct uart_port *up, struct console *con) { unsigned long flags; __uart_port_lock_irqsave(up, &flags); up->cons = con; __uart_port_unlock_irqrestore(up, flags); } /* Only for internal port lock wrapper usage. */ static inline bool __uart_port_using_nbcon(struct uart_port *up) { lockdep_assert_held_once(&up->lock); if (likely(!uart_console(up))) return false; /* * @up->cons is only modified under the port lock. Therefore it is * certain that it cannot disappear here. * * @up->cons->node is added/removed from the console list under the * port lock. Therefore it is certain that the registration status * cannot change here, thus @up->cons->flags can be read directly. */ if (hlist_unhashed_lockless(&up->cons->node) || !(up->cons->flags & CON_NBCON) || !up->cons->write_atomic) { return false; } return true; } /* Only for internal port lock wrapper usage. */ static inline bool __uart_port_nbcon_try_acquire(struct uart_port *up) { if (!__uart_port_using_nbcon(up)) return true; return nbcon_device_try_acquire(up->cons); } /* Only for internal port lock wrapper usage. */ static inline void __uart_port_nbcon_acquire(struct uart_port *up) { if (!__uart_port_using_nbcon(up)) return; while (!nbcon_device_try_acquire(up->cons)) cpu_relax(); } /* Only for internal port lock wrapper usage. */ static inline void __uart_port_nbcon_release(struct uart_port *up) { if (!__uart_port_using_nbcon(up)) return; nbcon_device_release(up->cons); } /** * uart_port_lock - Lock the UART port * @up: Pointer to UART port structure */ static inline void uart_port_lock(struct uart_port *up) { spin_lock(&up->lock); __uart_port_nbcon_acquire(up); } /** * uart_port_lock_irq - Lock the UART port and disable interrupts * @up: Pointer to UART port structure */ static inline void uart_port_lock_irq(struct uart_port *up) { spin_lock_irq(&up->lock); __uart_port_nbcon_acquire(up); } /** * uart_port_lock_irqsave - Lock the UART port, save and disable interrupts * @up: Pointer to UART port structure * @flags: Pointer to interrupt flags storage */ static inline void uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags) { spin_lock_irqsave(&up->lock, *flags); __uart_port_nbcon_acquire(up); } /** * uart_port_trylock - Try to lock the UART port * @up: Pointer to UART port structure * * Returns: True if lock was acquired, false otherwise */ static inline bool uart_port_trylock(struct uart_port *up) { if (!spin_trylock(&up->lock)) return false; if (!__uart_port_nbcon_try_acquire(up)) { spin_unlock(&up->lock); return false; } return true; } /** * uart_port_trylock_irqsave - Try to lock the UART port, save and disable interrupts * @up: Pointer to UART port structure * @flags: Pointer to interrupt flags storage * * Returns: True if lock was acquired, false otherwise */ static inline bool uart_port_trylock_irqsave(struct uart_port *up, unsigned long *flags) { if (!spin_trylock_irqsave(&up->lock, *flags)) return false; if (!__uart_port_nbcon_try_acquire(up)) { spin_unlock_irqrestore(&up->lock, *flags); return false; } return true; } /** * uart_port_unlock - Unlock the UART port * @up: Pointer to UART port structure */ static inline void uart_port_unlock(struct uart_port *up) { __uart_port_nbcon_release(up); spin_unlock(&up->lock); } /** * uart_port_unlock_irq - Unlock the UART port and re-enable interrupts * @up: Pointer to UART port structure */ static inline void uart_port_unlock_irq(struct uart_port *up) { __uart_port_nbcon_release(up); spin_unlock_irq(&up->lock); } /** * uart_port_unlock_irqrestore - Unlock the UART port, restore interrupts * @up: Pointer to UART port structure * @flags: The saved interrupt flags for restore */ static inline void uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags) { __uart_port_nbcon_release(up); spin_unlock_irqrestore(&up->lock, flags); } DEFINE_GUARD(uart_port_lock, struct uart_port *, uart_port_lock(_T), uart_port_unlock(_T)); DEFINE_GUARD_COND(uart_port_lock, _try, uart_port_trylock(_T)); DEFINE_GUARD(uart_port_lock_irq, struct uart_port *, uart_port_lock_irq(_T), uart_port_unlock_irq(_T)); DEFINE_LOCK_GUARD_1(uart_port_lock_irqsave, struct uart_port, uart_port_lock_irqsave(_T->lock, &_T->flags), uart_port_unlock_irqrestore(_T->lock, _T->flags), unsigned long flags); DEFINE_LOCK_GUARD_1_COND(uart_port_lock_irqsave, _try, uart_port_trylock_irqsave(_T->lock, &_T->flags)); static inline int serial_port_in(struct uart_port *up, int offset) { return up->serial_in(up, offset); } static inline void serial_port_out(struct uart_port *up, int offset, int value) { up->serial_out(up, offset, value); } /** * enum uart_pm_state - power states for UARTs * @UART_PM_STATE_ON: UART is powered, up and operational * @UART_PM_STATE_OFF: UART is powered off * @UART_PM_STATE_UNDEFINED: sentinel */ enum uart_pm_state { UART_PM_STATE_ON = 0, UART_PM_STATE_OFF = 3, /* number taken from ACPI */ UART_PM_STATE_UNDEFINED, }; /* * This is the state information which is persistent across opens. */ struct uart_state { struct tty_port port; enum uart_pm_state pm_state; atomic_t refcount; wait_queue_head_t remove_wait; struct uart_port *uart_port; }; #define UART_XMIT_SIZE PAGE_SIZE /* number of characters left in xmit buffer before we ask for more */ #define WAKEUP_CHARS 256 /** * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars * @up: uart_port structure describing the port * @chars: number of characters sent * * This function advances the tail of circular xmit buffer by the number of * @chars transmitted and handles accounting of transmitted bytes (into * @up's icount.tx). */ static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars) { struct tty_port *tport = &up->state->port; kfifo_skip_count(&tport->xmit_fifo, chars); up->icount.tx += chars; } static inline unsigned int uart_fifo_out(struct uart_port *up, unsigned char *buf, unsigned int chars) { struct tty_port *tport = &up->state->port; chars = kfifo_out(&tport->xmit_fifo, buf, chars); up->icount.tx += chars; return chars; } static inline unsigned int uart_fifo_get(struct uart_port *up, unsigned char *ch) { struct tty_port *tport = &up->state->port; unsigned int chars; chars = kfifo_get(&tport->xmit_fifo, ch); up->icount.tx += chars; return chars; } struct module; struct tty_driver; struct uart_driver { struct module *owner; const char *driver_name; const char *dev_name; int major; int minor; int nr; struct console *cons; /* * these are private; the low level driver should not * touch these; they should be initialised to NULL */ struct uart_state *state; struct tty_driver *tty_driver; }; void uart_write_wakeup(struct uart_port *port); /** * enum UART_TX_FLAGS -- flags for uart_port_tx_flags() * * @UART_TX_NOSTOP: don't call port->ops->stop_tx() on empty buffer */ enum UART_TX_FLAGS { UART_TX_NOSTOP = BIT(0), }; #define __uart_port_tx(uport, ch, flags, tx_ready, put_char, tx_done, \ for_test, for_post) \ ({ \ struct uart_port *__port = (uport); \ struct tty_port *__tport = &__port->state->port; \ unsigned int pending; \ \ for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) { \ if (__port->x_char) { \ (ch) = __port->x_char; \ (put_char); \ __port->x_char = 0; \ continue; \ } \ \ if (uart_tx_stopped(__port)) \ break; \ \ if (!kfifo_get(&__tport->xmit_fifo, &(ch))) \ break; \ \ (put_char); \ } \ \ (tx_done); \ \ pending = kfifo_len(&__tport->xmit_fifo); \ if (pending < WAKEUP_CHARS) { \ uart_write_wakeup(__port); \ \ if (!((flags) & UART_TX_NOSTOP) && pending == 0) \ __port->ops->stop_tx(__port); \ } \ \ pending; \ }) /** * uart_port_tx_limited -- transmit helper for uart_port with count limiting * @port: uart port * @ch: variable to store a character to be written to the HW * @count: a limit of characters to send * @tx_ready: can HW accept more data function * @put_char: function to write a character * @tx_done: function to call after the loop is done * * This helper transmits characters from the xmit buffer to the hardware using * @put_char(). It does so until @count characters are sent and while @tx_ready * evaluates to true. * * Returns: the number of characters in the xmit buffer when done. * * The expression in macro parameters shall be designed as follows: * * **tx_ready:** should evaluate to true if the HW can accept more data to * be sent. This parameter can be %true, which means the HW is always ready. * * **put_char:** shall write @ch to the device of @port. * * **tx_done:** when the write loop is done, this can perform arbitrary * action before potential invocation of ops->stop_tx() happens. If the * driver does not need to do anything, use e.g. ({}). * * For all of them, @port->lock is held, interrupts are locally disabled and * the expressions must not sleep. */ #define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \ unsigned int __count = (count); \ __uart_port_tx(port, ch, 0, tx_ready, put_char, tx_done, __count, \ __count--); \ }) /** * uart_port_tx_limited_flags -- transmit helper for uart_port with count limiting with flags * @port: uart port * @ch: variable to store a character to be written to the HW * @flags: %UART_TX_NOSTOP or similar * @count: a limit of characters to send * @tx_ready: can HW accept more data function * @put_char: function to write a character * @tx_done: function to call after the loop is done * * See uart_port_tx_limited() for more details. */ #define uart_port_tx_limited_flags(port, ch, flags, count, tx_ready, put_char, tx_done) ({ \ unsigned int __count = (count); \ __uart_port_tx(port, ch, flags, tx_ready, put_char, tx_done, __count, \ __count--); \ }) /** * uart_port_tx -- transmit helper for uart_port * @port: uart port * @ch: variable to store a character to be written to the HW * @tx_ready: can HW accept more data function * @put_char: function to write a character * * See uart_port_tx_limited() for more details. */ #define uart_port_tx(port, ch, tx_ready, put_char) \ __uart_port_tx(port, ch, 0, tx_ready, put_char, ({}), true, ({})) /** * uart_port_tx_flags -- transmit helper for uart_port with flags * @port: uart port * @ch: variable to store a character to be written to the HW * @flags: %UART_TX_NOSTOP or similar * @tx_ready: can HW accept more data function * @put_char: function to write a character * * See uart_port_tx_limited() for more details. */ #define uart_port_tx_flags(port, ch, flags, tx_ready, put_char) \ __uart_port_tx(port, ch, flags, tx_ready, put_char, ({}), true, ({})) /* * Baud rate helpers. */ void uart_update_timeout(struct uart_port *port, unsigned int cflag, unsigned int baud); unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, const struct ktermios *old, unsigned int min, 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 unsigned long uart_poll_timeout(struct uart_port *port) { unsigned long timeout = uart_fifo_timeout(port); return timeout > 6 ? (timeout / 2 - 2) : 1; } /* * Console helpers. */ struct earlycon_device { struct console *con; struct uart_port port; char options[32]; /* e.g., 115200n8 */ unsigned int baud; }; struct earlycon_id { char name[15]; char name_term; /* In case compiler didn't '\0' term name */ char compatible[128]; int (*setup)(struct earlycon_device *, const char *options); }; extern const struct earlycon_id __earlycon_table[]; extern const struct earlycon_id __earlycon_table_end[]; #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE) #define EARLYCON_USED_OR_UNUSED __used #else #define EARLYCON_USED_OR_UNUSED __maybe_unused #endif #define OF_EARLYCON_DECLARE(_name, compat, fn) \ static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \ EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \ __aligned(__alignof__(struct earlycon_id)) \ = { .name = __stringify(_name), \ .compatible = compat, \ .setup = fn } #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn) int of_setup_earlycon(const struct earlycon_id *match, unsigned long node, const char *options); #ifdef CONFIG_SERIAL_EARLYCON extern bool earlycon_acpi_spcr_enable __initdata; int setup_earlycon(char *buf); #else static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED; static inline int setup_earlycon(char *buf) { return 0; } #endif /* Variant of uart_console_registered() when the console_list_lock is held. */ static inline bool uart_console_registered_locked(struct uart_port *port) { return uart_console(port) && console_is_registered_locked(port->cons); } static inline bool uart_console_registered(struct uart_port *port) { return uart_console(port) && console_is_registered(port->cons); } int uart_parse_earlycon(char *p, enum uart_iotype *iotype, resource_size_t *addr, char **options); void uart_parse_options(const char *options, int *baud, int *parity, int *bits, int *flow); int uart_set_options(struct uart_port *port, struct console *co, int baud, int parity, int bits, int flow); struct tty_driver *uart_console_device(struct console *co, int *index); void uart_console_write(struct uart_port *port, const char *s, unsigned int count, void (*putchar)(struct uart_port *, unsigned char)); /* * Port/driver registration/removal */ int uart_register_driver(struct uart_driver *uart); void uart_unregister_driver(struct uart_driver *uart); int uart_add_one_port(struct uart_driver *reg, struct uart_port *port); void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port); int uart_read_port_properties(struct uart_port *port); int uart_read_and_validate_port_properties(struct uart_port *port); bool uart_match_port(const struct uart_port *port1, const struct uart_port *port2); /* * Power Management */ int uart_suspend_port(struct uart_driver *reg, struct uart_port *port); int uart_resume_port(struct uart_driver *reg, struct uart_port *port); static inline int uart_tx_stopped(struct uart_port *port) { struct tty_struct *tty = port->state->port.tty; if ((tty && tty->flow.stopped) || port->hw_stopped) return 1; return 0; } static inline bool uart_cts_enabled(struct uart_port *uport) { return !!(uport->status & UPSTAT_CTS_ENABLE); } static inline bool uart_softcts_mode(struct uart_port *uport) { upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS; return ((uport->status & mask) == UPSTAT_CTS_ENABLE); } /* * The following are helper functions for the low level drivers. */ void uart_handle_dcd_change(struct uart_port *uport, bool active); void uart_handle_cts_change(struct uart_port *uport, bool active); void uart_insert_char(struct uart_port *port, unsigned int status, unsigned int overrun, u8 ch, u8 flag); void uart_xchar_out(struct uart_port *uport, int offset); #ifdef CONFIG_MAGIC_SYSRQ_SERIAL #define SYSRQ_TIMEOUT (HZ * 5) bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch); static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch) { if (!port->sysrq) return 0; if (ch && time_before(jiffies, port->sysrq)) { if (sysrq_mask()) { handle_sysrq(ch); port->sysrq = 0; return 1; } if (uart_try_toggle_sysrq(port, ch)) return 1; } port->sysrq = 0; return 0; } static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch) { if (!port->sysrq) return 0; if (ch && time_before(jiffies, port->sysrq)) { if (sysrq_mask()) { port->sysrq_ch = ch; port->sysrq = 0; return 1; } if (uart_try_toggle_sysrq(port, ch)) return 1; } port->sysrq = 0; return 0; } static inline void uart_unlock_and_check_sysrq(struct uart_port *port) { u8 sysrq_ch; if (!port->has_sysrq) { uart_port_unlock(port); return; } sysrq_ch = port->sysrq_ch; port->sysrq_ch = 0; uart_port_unlock(port); if (sysrq_ch) handle_sysrq(sysrq_ch); } static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, unsigned long flags) { u8 sysrq_ch; if (!port->has_sysrq) { uart_port_unlock_irqrestore(port, flags); return; } sysrq_ch = port->sysrq_ch; port->sysrq_ch = 0; uart_port_unlock_irqrestore(port, flags); if (sysrq_ch) handle_sysrq(sysrq_ch); } #else /* CONFIG_MAGIC_SYSRQ_SERIAL */ static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch) { return 0; } static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch) { return 0; } static inline void uart_unlock_and_check_sysrq(struct uart_port *port) { uart_port_unlock(port); } static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, unsigned long flags) { uart_port_unlock_irqrestore(port, flags); } #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */ /* * We do the SysRQ and SAK checking like this... */ static inline int uart_handle_break(struct uart_port *port) { struct uart_state *state = port->state; if (port->handle_break) port->handle_break(port); #ifdef CONFIG_MAGIC_SYSRQ_SERIAL if (port->has_sysrq && uart_console(port)) { if (!port->sysrq) { port->sysrq = jiffies + SYSRQ_TIMEOUT; return 1; } port->sysrq = 0; } #endif if (port->flags & UPF_SAK) do_SAK(state->port.tty); return 0; } /* * UART_ENABLE_MS - determine if port should enable modem status irqs */ #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \ (cflag) & CRTSCTS || \ !((cflag) & CLOCAL)) int uart_get_rs485_mode(struct uart_port *port); #endif /* LINUX_SERIAL_CORE_H */
