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Diffstat (limited to 'include/linux/serial_core.h')
| -rw-r--r-- | include/linux/serial_core.h | 1033 |
1 files changed, 1033 insertions, 0 deletions
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h new file mode 100644 index 000000000..13bf20242 --- /dev/null +++ b/include/linux/serial_core.h @@ -0,0 +1,1033 @@ +/* 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/circ_buf.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 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; + +struct uart_port { + spinlock_t lock; /* port lock */ + unsigned long iobase; /* in/out[bwl] */ + unsigned char __iomem *membase; /* read/write[bwl] */ + unsigned int (*serial_in)(struct uart_port *, int); + void (*serial_out)(struct uart_port *, int, int); + 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 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 iotype; /* io access style */ + unsigned char quirks; /* internal quirks */ + +#define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */ +#define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */ +#define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */ +#define UPIO_MEM32 (SERIAL_IO_MEM32) /* 32b little endian */ +#define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */ +#define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */ +#define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */ +#define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */ + + /* quirks must be updated while holding port mutex */ +#define UPQ_NO_TXEN_TEST BIT(0) + + 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. + */ +#define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ ) +#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)) + + int 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; /* parent device */ + + unsigned long sysrq; /* sysrq timeout */ + unsigned int 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 serial_iso7816 iso7816; + void *private_data; /* generic platform data pointer */ +}; + +/** + * 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_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_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_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) +{ + return spin_trylock(&up->lock); +} + +/** + * 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) +{ + return spin_trylock_irqsave(&up->lock, *flags); +} + +/** + * uart_port_unlock - Unlock the UART port + * @up: Pointer to UART port structure + */ +static inline void uart_port_unlock(struct uart_port *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) +{ + 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) +{ + spin_unlock_irqrestore(&up->lock, 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; + struct circ_buf xmit; + + 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 circ_buf *xmit = &up->state->xmit; + + xmit->tail = (xmit->tail + chars) & (UART_XMIT_SIZE - 1); + up->icount.tx += 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); + +/* + * 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 int uart_poll_timeout(struct uart_port *port) +{ + int 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[16]; /* 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) + +extern 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 + +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, + 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); +int uart_remove_one_port(struct uart_driver *reg, 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); + +#define uart_circ_empty(circ) ((circ)->head == (circ)->tail) +#define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0) + +#define uart_circ_chars_pending(circ) \ + (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE)) + +#define uart_circ_chars_free(circ) \ + (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE)) + +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. + */ + +extern void uart_handle_dcd_change(struct uart_port *uport, + unsigned int status); +extern void uart_handle_cts_change(struct uart_port *uport, + unsigned int status); + +extern void uart_insert_char(struct uart_port *port, unsigned int status, + unsigned int overrun, unsigned int ch, unsigned int 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, unsigned int ch); + +static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int 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, unsigned int 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) +{ + int sysrq_ch; + + if (!port->has_sysrq) { + spin_unlock(&port->lock); + return; + } + + sysrq_ch = port->sysrq_ch; + port->sysrq_ch = 0; + + spin_unlock(&port->lock); + + if (sysrq_ch) + handle_sysrq(sysrq_ch); +} + +static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, + unsigned long flags) +{ + int sysrq_ch; + + if (!port->has_sysrq) { + spin_unlock_irqrestore(&port->lock, flags); + return; + } + + sysrq_ch = port->sysrq_ch; + port->sysrq_ch = 0; + + spin_unlock_irqrestore(&port->lock, flags); + + if (sysrq_ch) + handle_sysrq(sysrq_ch); +} +#else /* CONFIG_MAGIC_SYSRQ_SERIAL */ +static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) +{ + return 0; +} +static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) +{ + return 0; +} +static inline void uart_unlock_and_check_sysrq(struct uart_port *port) +{ + spin_unlock(&port->lock); +} +static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, + unsigned long flags) +{ + spin_unlock_irqrestore(&port->lock, 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 */ |