While comparing the OMAP-serial and the 8250 part of this I noticed that the the latter does not use runtime-pm. Here are the pieces. It is basically a get before first register access and a last_busy + put after last access. If I understand this correct, it should do nothing as long as pm_runtime_use_autosuspend() + pm_runtime_enable() isn't invoked on the device. Cc: mika.westerberg@xxxxxxxxxxxxxxx Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> --- drivers/tty/serial/8250/8250_core.c | 101 +++++++++++++++++++++++++++++++----- 1 file changed, 88 insertions(+), 13 deletions(-) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index d37eb08..1a91a89 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -38,6 +38,7 @@ #include <linux/nmi.h> #include <linux/mutex.h> #include <linux/slab.h> +#include <linux/pm_runtime.h> #ifdef CONFIG_SPARC #include <linux/sunserialcore.h> #endif @@ -553,10 +554,11 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep) * offset but the UART channel may only write to the corresponding * bit. */ + pm_runtime_get_sync(p->port.dev); 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) { @@ -571,7 +573,17 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep) serial_out(p, UART_EFR, 0); serial_out(p, UART_LCR, 0); } + + if (!device_may_wakeup(p->port.dev)) { + if (sleep) + pm_runtime_forbid(p->port.dev); + else + pm_runtime_allow(p->port.dev); + } } +out: + pm_runtime_mark_last_busy(p->port.dev); + pm_runtime_put_autosuspend(p->port.dev); } #ifdef CONFIG_SERIAL_8250_RSA @@ -1280,6 +1292,7 @@ static void serial8250_stop_tx(struct uart_port *port) struct uart_8250_port *up = container_of(port, struct uart_8250_port, port); + pm_runtime_get_sync(port->dev); __stop_tx(up); /* @@ -1289,6 +1302,8 @@ static void serial8250_stop_tx(struct uart_port *port) up->acr |= UART_ACR_TXDIS; serial_icr_write(up, UART_ACR, up->acr); } + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); } static void serial8250_start_tx(struct uart_port *port) @@ -1296,8 +1311,9 @@ static void serial8250_start_tx(struct uart_port *port) struct uart_8250_port *up = container_of(port, struct uart_8250_port, port); + pm_runtime_get_sync(port->dev); if (up->dma && !serial8250_tx_dma(up)) { - return; + goto out; } else if (!(up->ier & UART_IER_THRI)) { up->ier |= UART_IER_THRI; serial_port_out(port, UART_IER, up->ier); @@ -1318,6 +1334,9 @@ static void serial8250_start_tx(struct uart_port *port) up->acr &= ~UART_ACR_TXDIS; serial_icr_write(up, UART_ACR, up->acr); } +out: + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); } static void serial8250_stop_rx(struct uart_port *port) @@ -1325,9 +1344,14 @@ static void serial8250_stop_rx(struct uart_port *port) struct uart_8250_port *up = container_of(port, struct uart_8250_port, port); + pm_runtime_get_sync(port->dev); + up->ier &= ~UART_IER_RLSI; up->port.read_status_mask &= ~UART_LSR_DR; serial_port_out(port, UART_IER, up->ier); + + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); } static void serial8250_enable_ms(struct uart_port *port) @@ -1340,7 +1364,10 @@ static void serial8250_enable_ms(struct uart_port *port) return; up->ier |= UART_IER_MSI; + pm_runtime_get_sync(port->dev); serial_port_out(port, UART_IER, up->ier); + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); } /* @@ -1530,9 +1557,17 @@ 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); + unsigned int iir; + int ret; - return serial8250_handle_irq(port, iir); + pm_runtime_get_sync(port->dev); + + iir = serial_port_in(port, UART_IIR); + ret = serial8250_handle_irq(port, iir); + + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); + return ret; } /* @@ -1790,11 +1825,16 @@ static unsigned int serial8250_tx_empty(struct uart_port *port) unsigned long flags; unsigned int lsr; + pm_runtime_get_sync(port->dev); + 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); + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); + return (lsr & BOTH_EMPTY) == BOTH_EMPTY ? TIOCSER_TEMT : 0; } @@ -1805,7 +1845,10 @@ static unsigned int serial8250_get_mctrl(struct uart_port *port) unsigned int status; unsigned int ret; + pm_runtime_get_sync(port->dev); status = serial8250_modem_status(up); + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); ret = 0; if (status & UART_MSR_DCD) @@ -1838,7 +1881,10 @@ static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl) mcr = (mcr & up->mcr_mask) | up->mcr_force | up->mcr; + pm_runtime_get_sync(port->dev); serial_port_out(port, UART_MCR, mcr); + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); } static void serial8250_break_ctl(struct uart_port *port, int break_state) @@ -1847,6 +1893,7 @@ static void serial8250_break_ctl(struct uart_port *port, int break_state) container_of(port, struct uart_8250_port, port); unsigned long flags; + pm_runtime_get_sync(port->dev); spin_lock_irqsave(&port->lock, flags); if (break_state == -1) up->lcr |= UART_LCR_SBC; @@ -1854,6 +1901,8 @@ 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); + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); } /* @@ -1898,12 +1947,23 @@ 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); + unsigned char lsr; + int status; + + pm_runtime_get_sync(port->dev); - 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: + pm_runtime_mark_last_busy(up->dev); + pm_runtime_put_autosuspend(up->dev); + return status; } @@ -1914,6 +1974,7 @@ static void serial8250_put_poll_char(struct uart_port *port, struct uart_8250_port *up = container_of(port, struct uart_8250_port, port); + pm_runtime_get_sync(up->dev); /* * First save the IER then disable the interrupts */ @@ -1935,6 +1996,9 @@ static void serial8250_put_poll_char(struct uart_port *port, */ wait_for_xmitr(up, BOTH_EMPTY); serial_port_out(port, UART_IER, ier); + pm_runtime_mark_last_busy(up->dev); + pm_runtime_put_autosuspend(up->dev); + } #endif /* CONFIG_CONSOLE_POLL */ @@ -1961,6 +2025,7 @@ int serial8250_do_startup(struct uart_port *port) if (port->iotype != up->cur_iotype) set_io_from_upio(port); + pm_runtime_get_sync(port->dev); if (port->type == PORT_16C950) { /* Wake up and initialize UART */ up->acr = 0; @@ -1981,7 +2046,6 @@ 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()) @@ -2005,7 +2069,8 @@ 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; } /* @@ -2090,7 +2155,7 @@ int serial8250_do_startup(struct uart_port *port) } else { retval = serial_link_irq_chain(up); if (retval) - return retval; + goto out; } /* @@ -2188,8 +2253,11 @@ int serial8250_do_startup(struct uart_port *port) outb_p(0x80, icp); inb_p(icp); } - - return 0; + retval = 0; +out: + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); + return retval; } EXPORT_SYMBOL_GPL(serial8250_do_startup); @@ -2207,6 +2275,7 @@ void serial8250_do_shutdown(struct uart_port *port) container_of(port, struct uart_8250_port, port); unsigned long flags; + pm_runtime_get_sync(port->dev); /* * Disable interrupts from this port */ @@ -2246,6 +2315,8 @@ void serial8250_do_shutdown(struct uart_port *port) * the IRQ chain. */ serial_port_in(port, UART_RX); + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); del_timer_sync(&up->timer); up->timer.function = serial8250_timeout; @@ -2365,6 +2436,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, * Ok, we're now changing the port state. Do it with * interrupts disabled. */ + pm_runtime_get_sync(port->dev); spin_lock_irqsave(&port->lock, flags); /* @@ -2486,6 +2558,9 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, } serial8250_set_mctrl(port, port->mctrl); spin_unlock_irqrestore(&port->lock, flags); + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); + /* Don't rewrite B0 */ if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); -- 2.0.1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html