diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_core.c')
-rw-r--r-- | drivers/tty/serial/8250/8250_core.c | 253 |
1 files changed, 229 insertions, 24 deletions
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index bd67294..ca5cfdc 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -37,6 +37,8 @@ #include <linux/nmi.h> #include <linux/mutex.h> #include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/pm_runtime.h> #ifdef CONFIG_SPARC #include <linux/sunserialcore.h> #endif @@ -539,6 +541,53 @@ void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p) } EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos); +static void serial8250_rpm_get(struct uart_8250_port *p) +{ + if (!(p->capabilities & UART_CAP_RPM)) + return; + pm_runtime_get_sync(p->port.dev); +} + +static void serial8250_rpm_put(struct uart_8250_port *p) +{ + if (!(p->capabilities & UART_CAP_RPM)) + return; + pm_runtime_mark_last_busy(p->port.dev); + pm_runtime_put_autosuspend(p->port.dev); +} + +/* + * This two wrapper ensure, that enable_runtime_pm_tx() can be called more than + * once and disable_runtime_pm_tx() will still disable RPM because the fifo is + * empty and the HW can idle again. + */ +static void serial8250_rpm_get_tx(struct uart_8250_port *p) +{ + unsigned char rpm_active; + + if (!(p->capabilities & UART_CAP_RPM)) + return; + + rpm_active = xchg(&p->rpm_tx_active, 1); + if (rpm_active) + return; + pm_runtime_get_sync(p->port.dev); +} + +static void serial8250_rpm_put_tx(struct uart_8250_port *p) +{ + unsigned char rpm_active; + + if (!(p->capabilities & UART_CAP_RPM)) + return; + + rpm_active = xchg(&p->rpm_tx_active, 0); + if (!rpm_active) + return; + pm_runtime_mark_last_busy(p->port.dev); + pm_runtime_put_autosuspend(p->port.dev); +} + /* * IER sleep support. UARTs which have EFRs need the "extended * capability" bit enabled. Note that on XR16C850s, we need to @@ -553,10 +602,11 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep) * offset but the UART channel may only write to the corresponding * bit. */ + serial8250_rpm_get(p); if ((p->port.type == PORT_XR17V35X) || (p->port.type == PORT_XR17D15X)) { serial_out(p, UART_EXAR_SLEEP, sleep ? 0xff : 0); - return; + goto out; } if (p->capabilities & UART_CAP_SLEEP) { @@ -572,6 +622,8 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep) serial_out(p, UART_LCR, 0); } } +out: + serial8250_rpm_put(p); } #ifdef CONFIG_SERIAL_8250_RSA @@ -1272,6 +1324,7 @@ static inline void __stop_tx(struct uart_8250_port *p) if (p->ier & UART_IER_THRI) { p->ier &= ~UART_IER_THRI; serial_out(p, UART_IER, p->ier); + serial8250_rpm_put_tx(p); } } @@ -1279,6 +1332,7 @@ static void serial8250_stop_tx(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); + serial8250_rpm_get(up); __stop_tx(up); /* @@ -1288,12 +1342,14 @@ static void serial8250_stop_tx(struct uart_port *port) up->acr |= UART_ACR_TXDIS; serial_icr_write(up, UART_ACR, up->acr); } + serial8250_rpm_put(up); } static void serial8250_start_tx(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); + serial8250_rpm_get_tx(up); if (up->dma && !serial8250_tx_dma(up)) { return; } else if (!(up->ier & UART_IER_THRI)) { @@ -1318,13 +1374,27 @@ static void serial8250_start_tx(struct uart_port *port) } } +static void serial8250_throttle(struct uart_port *port) +{ + port->throttle(port); +} + +static void serial8250_unthrottle(struct uart_port *port) +{ + port->unthrottle(port); +} + static void serial8250_stop_rx(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); - up->ier &= ~UART_IER_RLSI; + serial8250_rpm_get(up); + + up->ier &= ~(UART_IER_RLSI | UART_IER_RDI); up->port.read_status_mask &= ~UART_LSR_DR; serial_port_out(port, UART_IER, up->ier); + + serial8250_rpm_put(up); } static void serial8250_enable_ms(struct uart_port *port) @@ -1336,7 +1406,10 @@ static void serial8250_enable_ms(struct uart_port *port) return; up->ier |= UART_IER_MSI; + + serial8250_rpm_get(up); serial_port_out(port, UART_IER, up->ier); + serial8250_rpm_put(up); } /* @@ -1458,11 +1531,17 @@ void serial8250_tx_chars(struct uart_8250_port *up) DEBUG_INTR("THRE..."); - if (uart_circ_empty(xmit)) + /* + * With RPM enabled, we have to wait once the FIFO is empty before the + * HW can go idle. So we get here once again with empty FIFO and disable + * the interrupt and RPM in __stop_tx() + */ + if (uart_circ_empty(xmit) && !(up->capabilities & UART_CAP_RPM)) __stop_tx(up); } EXPORT_SYMBOL_GPL(serial8250_tx_chars); +/* Caller holds uart port lock */ unsigned int serial8250_modem_status(struct uart_8250_port *up) { struct uart_port *port = &up->port; @@ -1525,9 +1604,17 @@ EXPORT_SYMBOL_GPL(serial8250_handle_irq); static int serial8250_default_handle_irq(struct uart_port *port) { - unsigned int iir = serial_port_in(port, UART_IIR); + struct uart_8250_port *up = up_to_u8250p(port); + unsigned int iir; + int ret; + + serial8250_rpm_get(up); - return serial8250_handle_irq(port, iir); + iir = serial_port_in(port, UART_IIR); + ret = serial8250_handle_irq(port, iir); + + serial8250_rpm_put(up); + return ret; } /* @@ -1784,11 +1871,15 @@ static unsigned int serial8250_tx_empty(struct uart_port *port) unsigned long flags; unsigned int lsr; + serial8250_rpm_get(up); + spin_lock_irqsave(&port->lock, flags); lsr = serial_port_in(port, UART_LSR); up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS; spin_unlock_irqrestore(&port->lock, flags); + serial8250_rpm_put(up); + return (lsr & BOTH_EMPTY) == BOTH_EMPTY ? TIOCSER_TEMT : 0; } @@ -1798,7 +1889,9 @@ static unsigned int serial8250_get_mctrl(struct uart_port *port) unsigned int status; unsigned int ret; + serial8250_rpm_get(up); status = serial8250_modem_status(up); + serial8250_rpm_put(up); ret = 0; if (status & UART_MSR_DCD) @@ -1838,6 +1931,7 @@ static void serial8250_break_ctl(struct uart_port *port, int break_state) struct uart_8250_port *up = up_to_u8250p(port); unsigned long flags; + serial8250_rpm_get(up); spin_lock_irqsave(&port->lock, flags); if (break_state == -1) up->lcr |= UART_LCR_SBC; @@ -1845,6 +1939,7 @@ static void serial8250_break_ctl(struct uart_port *port, int break_state) up->lcr &= ~UART_LCR_SBC; serial_port_out(port, UART_LCR, up->lcr); spin_unlock_irqrestore(&port->lock, flags); + serial8250_rpm_put(up); } /* @@ -1889,12 +1984,23 @@ static void wait_for_xmitr(struct uart_8250_port *up, int bits) static int serial8250_get_poll_char(struct uart_port *port) { - unsigned char lsr = serial_port_in(port, UART_LSR); + struct uart_8250_port *up = up_to_u8250p(port); + unsigned char lsr; + int status; + + serial8250_rpm_get(up); + + lsr = serial_port_in(port, UART_LSR); - if (!(lsr & UART_LSR_DR)) - return NO_POLL_CHAR; + if (!(lsr & UART_LSR_DR)) { + status = NO_POLL_CHAR; + goto out; + } - return serial_port_in(port, UART_RX); + status = serial_port_in(port, UART_RX); +out: + serial8250_rpm_put(up); + return status; } @@ -1904,6 +2010,7 @@ static void serial8250_put_poll_char(struct uart_port *port, unsigned int ier; struct uart_8250_port *up = up_to_u8250p(port); + serial8250_rpm_get(up); /* * First save the IER then disable the interrupts */ @@ -1925,11 +2032,12 @@ static void serial8250_put_poll_char(struct uart_port *port, */ wait_for_xmitr(up, BOTH_EMPTY); serial_port_out(port, UART_IER, ier); + serial8250_rpm_put(up); } #endif /* CONFIG_CONSOLE_POLL */ -static int serial8250_startup(struct uart_port *port) +int serial8250_do_startup(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); unsigned long flags; @@ -1950,6 +2058,7 @@ static int serial8250_startup(struct uart_port *port) if (port->iotype != up->cur_iotype) set_io_from_upio(port); + serial8250_rpm_get(up); if (port->type == PORT_16C950) { /* Wake up and initialize UART */ up->acr = 0; @@ -1970,7 +2079,6 @@ static int serial8250_startup(struct uart_port *port) */ enable_rsa(up); #endif - /* * Clear the FIFO buffers and disable them. * (they will be reenabled in set_termios()) @@ -1980,8 +2088,8 @@ static int serial8250_startup(struct uart_port *port) /* * Clear the interrupt registers. */ - serial_port_in(port, UART_LSR); - serial_port_in(port, UART_RX); + if (serial_port_in(port, UART_LSR) & UART_LSR_DR) + serial_port_in(port, UART_RX); serial_port_in(port, UART_IIR); serial_port_in(port, UART_MSR); @@ -1994,7 +2102,8 @@ static int serial8250_startup(struct uart_port *port) (serial_port_in(port, UART_LSR) == 0xff)) { printk_ratelimited(KERN_INFO "ttyS%d: LSR safety check engaged!\n", serial_index(port)); - return -ENODEV; + retval = -ENODEV; + goto out; } /* @@ -2079,7 +2188,7 @@ static int serial8250_startup(struct uart_port *port) } else { retval = serial_link_irq_chain(up); if (retval) - return retval; + goto out; } /* @@ -2141,8 +2250,8 @@ dont_test_tx_en: * saved flags to avoid getting false values from polling * routines or the previous session. */ - serial_port_in(port, UART_LSR); - serial_port_in(port, UART_RX); + if (serial_port_in(port, UART_LSR) & UART_LSR_DR) + serial_port_in(port, UART_RX); serial_port_in(port, UART_IIR); serial_port_in(port, UART_MSR); up->lsr_saved_flags = 0; @@ -2177,15 +2286,26 @@ dont_test_tx_en: outb_p(0x80, icp); inb_p(icp); } + retval = 0; +out: + serial8250_rpm_put(up); + return retval; +} +EXPORT_SYMBOL_GPL(serial8250_do_startup); - return 0; +static int serial8250_startup(struct uart_port *port) +{ + if (port->startup) + return port->startup(port); + return serial8250_do_startup(port); } -static void serial8250_shutdown(struct uart_port *port) +void serial8250_do_shutdown(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); unsigned long flags; + serial8250_rpm_get(up); /* * Disable interrupts from this port */ @@ -2224,13 +2344,24 @@ static void serial8250_shutdown(struct uart_port *port) * Read data port to reset things, and then unlink from * the IRQ chain. */ - serial_port_in(port, UART_RX); + if (serial_port_in(port, UART_LSR) & UART_LSR_DR) + serial_port_in(port, UART_RX); + serial8250_rpm_put(up); del_timer_sync(&up->timer); up->timer.function = serial8250_timeout; if (port->irq) serial_unlink_irq_chain(up); } +EXPORT_SYMBOL_GPL(serial8250_do_shutdown); + +static void serial8250_shutdown(struct uart_port *port) +{ + if (port->shutdown) + port->shutdown(port); + else + serial8250_do_shutdown(port); +} static unsigned int serial8250_get_divisor(struct uart_port *port, unsigned int baud) { @@ -2319,11 +2450,9 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, * the trigger, or the MCR RTS bit is cleared. In the case where * the remote UART is not using CTS auto flow control, we must * have sufficient FIFO entries for the latency of the remote - * UART to respond. IOW, at least 32 bytes of FIFO. Also enable - * AFE if hw flow control is supported + * UART to respond. IOW, at least 32 bytes of FIFO. */ - if ((up->capabilities & UART_CAP_AFE && (port->fifosize >= 32)) || - (port->flags & UPF_HARD_FLOW)) { + if (up->capabilities & UART_CAP_AFE && port->fifosize >= 32) { up->mcr &= ~UART_MCR_AFE; if (termios->c_cflag & CRTSCTS) up->mcr |= UART_MCR_AFE; @@ -2333,6 +2462,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, * Ok, we're now changing the port state. Do it with * interrupts disabled. */ + serial8250_rpm_get(up); spin_lock_irqsave(&port->lock, flags); /* @@ -2454,6 +2584,8 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, } serial8250_set_mctrl(port, port->mctrl); spin_unlock_irqrestore(&port->lock, flags); + serial8250_rpm_put(up); + /* Don't rewrite B0 */ if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); @@ -2843,6 +2975,42 @@ serial8250_verify_port(struct uart_port *port, struct serial_struct *ser) return 0; } +static int serial8250_ioctl(struct uart_port *port, unsigned int cmd, + unsigned long arg) +{ + struct uart_8250_port *up = + container_of(port, struct uart_8250_port, port); + int ret; + struct serial_rs485 rs485_config; + + if (!up->rs485_config) + return -ENOIOCTLCMD; + + switch (cmd) { + case TIOCSRS485: + if (copy_from_user(&rs485_config, (void __user *)arg, + sizeof(rs485_config))) + return -EFAULT; + + ret = up->rs485_config(up, &rs485_config); + if (ret) + return ret; + + memcpy(&up->rs485, &rs485_config, sizeof(rs485_config)); + + return 0; + case TIOCGRS485: + if (copy_to_user((void __user *)arg, &up->rs485, + sizeof(up->rs485))) + return -EFAULT; + return 0; + default: + break; + } + + return -ENOIOCTLCMD; +} + static const char * serial8250_type(struct uart_port *port) { @@ -2859,6 +3027,8 @@ static struct uart_ops serial8250_pops = { .get_mctrl = serial8250_get_mctrl, .stop_tx = serial8250_stop_tx, .start_tx = serial8250_start_tx, + .throttle = serial8250_throttle, + .unthrottle = serial8250_unthrottle, .stop_rx = serial8250_stop_rx, .enable_ms = serial8250_enable_ms, .break_ctl = serial8250_break_ctl, @@ -2872,6 +3042,7 @@ static struct uart_ops serial8250_pops = { .request_port = serial8250_request_port, .config_port = serial8250_config_port, .verify_port = serial8250_verify_port, + .ioctl = serial8250_ioctl, #ifdef CONFIG_CONSOLE_POLL .poll_get_char = serial8250_get_poll_char, .poll_put_char = serial8250_put_poll_char, @@ -2880,6 +3051,24 @@ static struct uart_ops serial8250_pops = { static struct uart_8250_port serial8250_ports[UART_NR]; +/** + * serial8250_get_port - retrieve struct uart_8250_port + * @line: serial line number + * + * This function retrieves struct uart_8250_port for the specific line. + * This struct *must* *not* be used to perform a 8250 or serial core operation + * which is not accessible otherwise. Its only purpose is to make the struct + * accessible to the runtime-pm callbacks for context suspend/restore. + * The lock assumption made here is none because runtime-pm suspend/resume + * callbacks should not be invoked if there is any operation performed on the + * port. + */ +struct uart_8250_port *serial8250_get_port(int line) +{ + return &serial8250_ports[line]; +} +EXPORT_SYMBOL_GPL(serial8250_get_port); + static void (*serial8250_isa_config)(int port, struct uart_port *up, unsigned short *capabilities); @@ -3007,6 +3196,8 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count) touch_nmi_watchdog(); + serial8250_rpm_get(up); + if (port->sysrq || oops_in_progress) locked = spin_trylock_irqsave(&port->lock, flags); else @@ -3043,6 +3234,7 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count) if (locked) spin_unlock_irqrestore(&port->lock, flags); + serial8250_rpm_put(up); } static int __init serial8250_console_setup(struct console *co, char *options) @@ -3324,6 +3516,11 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port * if (uart_match_port(&serial8250_ports[i].port, port)) return &serial8250_ports[i]; + /* try line number first if still available */ + i = port->line; + if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN && + serial8250_ports[i].port.iobase == 0) + return &serial8250_ports[i]; /* * We didn't find a matching entry, so look for the first * free entry. We look for one which hasn't been previously @@ -3388,6 +3585,10 @@ int serial8250_register_8250_port(struct uart_8250_port *up) uart->port.fifosize = up->port.fifosize; uart->tx_loadsz = up->tx_loadsz; uart->capabilities = up->capabilities; + uart->rs485_config = up->rs485_config; + uart->rs485 = up->rs485; + uart->port.throttle = up->port.throttle; + uart->port.unthrottle = up->port.unthrottle; /* Take tx_loadsz from fifosize if it wasn't set separately */ if (uart->port.fifosize && !uart->tx_loadsz) @@ -3410,6 +3611,10 @@ int serial8250_register_8250_port(struct uart_8250_port *up) /* Possibly override set_termios call */ if (up->port.set_termios) uart->port.set_termios = up->port.set_termios; + if (up->port.startup) + uart->port.startup = up->port.startup; + if (up->port.shutdown) + uart->port.shutdown = up->port.shutdown; if (up->port.pm) uart->port.pm = up->port.pm; if (up->port.handle_break) |