diff options
| -rw-r--r-- | drivers/tty/serial/8250/8250.h | 1 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250_core.c | 133 | ||||
| -rw-r--r-- | include/linux/serial_8250.h | 1 |
3 files changed, 122 insertions, 13 deletions
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 85bfec58d77c..1bcb4b2141a6 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -72,6 +72,7 @@ struct serial8250_config { #define UART_CAP_UUE (1 << 12) /* UART needs IER bit 6 set (Xscale) */ #define UART_CAP_RTOIE (1 << 13) /* UART needs IER bit 4 set (Xscale, Tegra) */ #define UART_CAP_HFIFO (1 << 14) /* UART has a "hidden" FIFO */ +#define UART_CAP_RPM (1 << 15) /* Runtime PM is active while idle */ #define UART_BUG_QUOT (1 << 0) /* UART has buggy quot LSB */ #define UART_BUG_TXEN (1 << 1) /* UART has buggy TX IIR status */ diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 68c44d97091b..3cf5c98013e4 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -38,6 +38,7 @@ #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 @@ -540,6 +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 @@ -554,10 +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) { @@ -573,6 +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 @@ -1273,6 +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); } } @@ -1280,6 +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); /* @@ -1289,12 +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)) { @@ -1333,9 +1388,13 @@ static void serial8250_stop_rx(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); + serial8250_rpm_get(up); + up->ier &= ~UART_IER_RLSI; 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) @@ -1347,7 +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); } /* @@ -1469,7 +1531,12 @@ 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); @@ -1537,9 +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; } /* @@ -1796,11 +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; } @@ -1810,7 +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) @@ -1850,6 +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; @@ -1857,6 +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); } /* @@ -1901,12 +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); - if (!(lsr & UART_LSR_DR)) - return NO_POLL_CHAR; + lsr = serial_port_in(port, UART_LSR); - return serial_port_in(port, UART_RX); + if (!(lsr & UART_LSR_DR)) { + status = NO_POLL_CHAR; + goto out; + } + + status = serial_port_in(port, UART_RX); +out: + serial8250_rpm_put(up); + return status; } @@ -1916,6 +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 */ @@ -1937,6 +2032,7 @@ 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 */ @@ -1962,6 +2058,7 @@ int serial8250_do_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; @@ -1982,7 +2079,6 @@ int serial8250_do_startup(struct uart_port *port) */ enable_rsa(up); #endif - /* * Clear the FIFO buffers and disable them. * (they will be reenabled in set_termios()) @@ -2006,7 +2102,8 @@ int serial8250_do_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; } /* @@ -2091,7 +2188,7 @@ int serial8250_do_startup(struct uart_port *port) } else { retval = serial_link_irq_chain(up); if (retval) - return retval; + goto out; } /* @@ -2189,8 +2286,10 @@ dont_test_tx_en: outb_p(0x80, icp); inb_p(icp); } - - return 0; + retval = 0; +out: + serial8250_rpm_put(up); + return retval; } EXPORT_SYMBOL_GPL(serial8250_do_startup); @@ -2206,6 +2305,7 @@ 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 */ @@ -2245,6 +2345,7 @@ void serial8250_do_shutdown(struct uart_port *port) * the IRQ chain. */ serial_port_in(port, UART_RX); + serial8250_rpm_put(up); del_timer_sync(&up->timer); up->timer.function = serial8250_timeout; @@ -2360,6 +2461,7 @@ 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); /* @@ -2481,6 +2583,8 @@ 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); @@ -3091,6 +3195,8 @@ 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 @@ -3127,6 +3233,7 @@ 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) diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index 6fc9d7bee05e..c267412a3ef4 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -84,6 +84,7 @@ struct uart_8250_port { unsigned char mcr_mask; /* mask of user bits */ unsigned char mcr_force; /* mask of forced bits */ unsigned char cur_iotype; /* Running I/O type */ + unsigned char rpm_tx_active; /* * Some bits in registers are cleared on a read, so they must |