printf: Remove unused 'bprintf'

[drm/drm-misc.git] / include / linux / serial_core.h

/* 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;

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            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           iotype;                 /* io access style */

#define UPIO_UNKNOWN            ((unsigned char)~0U)    /* UCHAR_MAX */
#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 */

        unsigned char           quirks;                 /* internal quirks */

        /* internal 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.
         */
#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);
}

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);
}

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);
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 */