| Message ID | 20211115084203.56478-2-tony@atomide.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/7] serial: core: Add support of runtime PM | expand |
Hi, * Johan Hovold <johan@kernel.org> [211130 10:29]: > On Mon, Nov 15, 2021 at 10:41:57AM +0200, Tony Lindgren wrote: > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > > > 8250 driver has wrong implementation of runtime power management, i.e. > > it uses an irq_safe flag. The irq_safe flag takes a permanent usage count > > on the parent device preventing the parent from idling. This patch > > prepares for making runtime power management generic by adding runtime PM > > calls to serial core once for all UART drivers. > > > > As we have serial drivers that do not enable runtime PM, and drivers that > > enable runtime PM, we add new functions for serial_pm_resume_and_get() and > > serial_pm_autosuspend() functions to handle errors and allow the use also > > for cases when runtime PM is not enabled. The other option considered was > > to not check for runtime PM enable errors. But some CPUs can hang when the > > clocks are not enabled for the device, so ignoring the errors is not a good > > option. Eventually with the serial port drivers updated, we should be able > > to just switch to using the standard runtime PM calls with no need for the > > wrapper functions. > > A third option which needs to be considered is to always enable runtime > pm in core but to keep the ports active while they are opened unless a > driver opts in for more aggressive power management. This is how USB > devices are handled for example. > > A next step could then be to move over uart_change_pm() to be handled > from the pm callbacks. Yes that would be nice to do eventually :) > > @@ -1824,12 +1901,16 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i) > > } > > > > if (capable(CAP_SYS_ADMIN)) { > > + err = serial_pm_resume_and_get(uport->dev); > > + if (err < 0) > > + goto out; > > pm_state = state->pm_state; > > if (pm_state != UART_PM_STATE_ON) > > uart_change_pm(state, UART_PM_STATE_ON); > > spin_lock_irq(&uport->lock); > > status = uport->ops->get_mctrl(uport); > > spin_unlock_irq(&uport->lock); > > + serial_pm_autosuspend(uport->dev); > > if (pm_state != UART_PM_STATE_ON) > > uart_change_pm(state, pm_state); > > The interaction with uart_change_pm() looks inconsistent. Why resume > before the state change and also suspend *before* updating the pm state? Good point. > That is, shouldn't the suspend go after uart_change_pm()? And similar in > other places. Yes agreed, runtime PM may disable the clock and shut down the UART so should be done after uart_change_pm(). BTW, Andy has follow-up patches to also drop the old uart_pm in favor of runtime PM :) > > @@ -2050,6 +2131,7 @@ uart_set_options(struct uart_port *port, struct console *co, > > { > > struct ktermios termios; > > static struct ktermios dummy; > > + int ret; > > > > /* > > * Ensure that the serial-console lock is initialised early. > > @@ -2089,7 +2171,17 @@ uart_set_options(struct uart_port *port, struct console *co, > > */ > > port->mctrl |= TIOCM_DTR; > > > > - port->ops->set_termios(port, &termios, &dummy); > > + /* At early stage device is not created yet, we can't do PM */ > > + if (port->dev) { > > Checking port->dev here looks a bit hacky. As this is kernel console related we may be able to just leave out the runtime PM calls here, see the two commits below. Andy, do you have some comments? > Can you expand on this and also on how this relates to console ports > presumably never being runtime suspended? See the following two commits for kernel console handling: bedb404e91bb ("serial: 8250_port: Don't use power management for kernel console") a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Thanks for looking through the patches again, I'll take a look at all your comments and will repost after the merge window. Regards, Tony
On Thu, Dec 09, 2021 at 09:29:44AM +0200, Tony Lindgren wrote: > * Johan Hovold <johan@kernel.org> [211130 10:29]: > > On Mon, Nov 15, 2021 at 10:41:57AM +0200, Tony Lindgren wrote: > > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > > > > > 8250 driver has wrong implementation of runtime power management, i.e. > > > it uses an irq_safe flag. The irq_safe flag takes a permanent usage count > > > on the parent device preventing the parent from idling. This patch > > > prepares for making runtime power management generic by adding runtime PM > > > calls to serial core once for all UART drivers. > > > > > > As we have serial drivers that do not enable runtime PM, and drivers that > > > enable runtime PM, we add new functions for serial_pm_resume_and_get() and > > > serial_pm_autosuspend() functions to handle errors and allow the use also > > > for cases when runtime PM is not enabled. The other option considered was > > > to not check for runtime PM enable errors. But some CPUs can hang when the > > > clocks are not enabled for the device, so ignoring the errors is not a good > > > option. Eventually with the serial port drivers updated, we should be able > > > to just switch to using the standard runtime PM calls with no need for the > > > wrapper functions. > > > > A third option which needs to be considered is to always enable runtime > > pm in core but to keep the ports active while they are opened unless a > > driver opts in for more aggressive power management. This is how USB > > devices are handled for example. > > > > A next step could then be to move over uart_change_pm() to be handled > > from the pm callbacks. > > Yes that would be nice to do eventually :) > > > > @@ -1824,12 +1901,16 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i) > > > } > > > > > > if (capable(CAP_SYS_ADMIN)) { > > > + err = serial_pm_resume_and_get(uport->dev); > > > + if (err < 0) > > > + goto out; > > > pm_state = state->pm_state; > > > if (pm_state != UART_PM_STATE_ON) > > > uart_change_pm(state, UART_PM_STATE_ON); > > > spin_lock_irq(&uport->lock); > > > status = uport->ops->get_mctrl(uport); > > > spin_unlock_irq(&uport->lock); > > > + serial_pm_autosuspend(uport->dev); > > > if (pm_state != UART_PM_STATE_ON) > > > uart_change_pm(state, pm_state); > > > > The interaction with uart_change_pm() looks inconsistent. Why resume > > before the state change and also suspend *before* updating the pm state? > > Good point. > > > That is, shouldn't the suspend go after uart_change_pm()? And similar in > > other places. > > Yes agreed, runtime PM may disable the clock and shut down the UART so > should be done after uart_change_pm(). > > BTW, Andy has follow-up patches to also drop the old uart_pm in favor of > runtime PM :) Yeah, but they are just removals without any proper replacements where the current drivers already are using some kind of runtime PM. I was focused and able to test only 8250 part. > > > @@ -2050,6 +2131,7 @@ uart_set_options(struct uart_port *port, struct console *co, > > > { > > > struct ktermios termios; > > > static struct ktermios dummy; > > > + int ret; > > > > > > /* > > > * Ensure that the serial-console lock is initialised early. > > > @@ -2089,7 +2171,17 @@ uart_set_options(struct uart_port *port, struct console *co, > > > */ > > > port->mctrl |= TIOCM_DTR; > > > > > > - port->ops->set_termios(port, &termios, &dummy); > > > + /* At early stage device is not created yet, we can't do PM */ > > > + if (port->dev) { > > > > Checking port->dev here looks a bit hacky. > > As this is kernel console related we may be able to just leave out the > runtime PM calls here, see the two commits below. Andy, do you have some > comments? IIRC the uart_set_options() can be called during early boot stages where no device is present and we need to handle those cases, otherwise it will be KABOOMs. I.o.w. we3 may not get rid of those checks (at least in a simple way). > > Can you expand on this and also on how this relates to console ports > > presumably never being runtime suspended? > > See the following two commits for kernel console handling: > > bedb404e91bb ("serial: 8250_port: Don't use power management for kernel console") > a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") > > Thanks for looking through the patches again, I'll take a look at all > your comments and will repost after the merge window. Thanks, Tony, for moving this forward and Johan for good review!
Hi, * Andy Shevchenko <andriy.shevchenko@intel.com> [211209 10:37]: > On Thu, Dec 09, 2021 at 09:29:44AM +0200, Tony Lindgren wrote: > > * Johan Hovold <johan@kernel.org> [211130 10:29]: > > > On Mon, Nov 15, 2021 at 10:41:57AM +0200, Tony Lindgren wrote: > > > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > > > > > > > 8250 driver has wrong implementation of runtime power management, i.e. > > > > it uses an irq_safe flag. The irq_safe flag takes a permanent usage count > > > > on the parent device preventing the parent from idling. This patch > > > > prepares for making runtime power management generic by adding runtime PM > > > > calls to serial core once for all UART drivers. > > > > > > > > As we have serial drivers that do not enable runtime PM, and drivers that > > > > enable runtime PM, we add new functions for serial_pm_resume_and_get() and > > > > serial_pm_autosuspend() functions to handle errors and allow the use also > > > > for cases when runtime PM is not enabled. The other option considered was > > > > to not check for runtime PM enable errors. But some CPUs can hang when the > > > > clocks are not enabled for the device, so ignoring the errors is not a good > > > > option. Eventually with the serial port drivers updated, we should be able > > > > to just switch to using the standard runtime PM calls with no need for the > > > > wrapper functions. > > > > > > A third option which needs to be considered is to always enable runtime > > > pm in core but to keep the ports active while they are opened unless a > > > driver opts in for more aggressive power management. This is how USB > > > devices are handled for example. > > > > > > A next step could then be to move over uart_change_pm() to be handled > > > from the pm callbacks. > > > > Yes that would be nice to do eventually :) I think we should do the "third option" above as the first preparatory patch. It can be done separately from the rest of the series, and we avoid adding serial layer specific wrappers around runtime PM calls in the later patches. Below is what I came up with for the preparatory patch, can you guys please take a look and see if you have better ideas? For system suspend and resume, it seems we don't need to do anything as runtime PM is anyways disabled already in prepare. Andy, care to give the following also a try for your serial port test cases? Regards, Tony 8< -------------------- diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -997,6 +997,7 @@ int serial8250_register_8250_port(const struct uart_8250_port *up) uart->port.regshift = up->port.regshift; uart->port.iotype = up->port.iotype; uart->port.flags = up->port.flags | UPF_BOOT_AUTOCONF; + uart->port.supports_autosuspend = up->port.supports_autosuspend; uart->bugs = up->bugs; uart->port.mapbase = up->port.mapbase; uart->port.mapsize = up->port.mapsize; diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -1352,6 +1352,7 @@ static int omap8250_probe(struct platform_device *pdev) up.rs485_start_tx = serial8250_em485_start_tx; up.rs485_stop_tx = serial8250_em485_stop_tx; up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); + up.port.supports_autosuspend = 1; ret = of_alias_get_id(np, "serial"); if (ret < 0) { diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -16,6 +16,7 @@ #include <linux/console.h> #include <linux/gpio/consumer.h> #include <linux/of.h> +#include <linux/pm_runtime.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/device.h> @@ -184,6 +185,7 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state, int init_hw) { struct uart_port *uport = uart_port_check(state); + struct device *dev = uport->dev; unsigned long flags; unsigned long page; int retval = 0; @@ -191,6 +193,32 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state, if (uport->type == PORT_UNKNOWN) return 1; + /* Always enable autosuspend and consider child devices for serdev */ + pm_runtime_use_autosuspend(dev); + pm_suspend_ignore_children(dev, false); + + /* + * If the port driver did not enable runtime PM in probe, do it now. + * Devices that did not enable runtime PM get set active so we can + * properly handler the returned errors for runtime PM calls. + */ + if (!pm_runtime_enabled(dev)) { + pm_runtime_set_active(dev); + pm_runtime_enable(dev); + } else { + uport->implements_pm_runtime = 1; + } + + /* + * Keep the port enabled unless autosuspend is supported. + * Released in uart_shutdown(). + */ + if (!uport->supports_autosuspend) { + retval = pm_runtime_resume_and_get(dev); + if (retval < 0) + return retval; + } + /* * Make sure the device is in D0 state. */ @@ -279,6 +307,7 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state) { struct uart_port *uport = uart_port_check(state); struct tty_port *port = &state->port; + struct device *dev = uport->dev; unsigned long flags; char *xmit_buf = NULL; @@ -313,6 +342,19 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state) */ tty_port_set_suspended(port, 0); + /* Runtime PM paired with configuration done in uart_port_startup() */ + if (uport) { + dev = uport->dev; + pm_runtime_dont_use_autosuspend(dev); + pm_suspend_ignore_children(dev, true); + if (!uport->supports_autosuspend) + pm_runtime_put_sync(dev); + if (!uport->implements_pm_runtime) { + pm_runtime_set_suspended(dev); + pm_runtime_disable(dev); + } + } + /* * Do not free() the transmit buffer page under the port lock since * this can create various circular locking scenarios. For instance, diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -249,6 +249,8 @@ struct uart_port { unsigned char hub6; /* this should be in the 8250 driver */ unsigned char suspended; unsigned char console_reinit; + unsigned long implements_pm_runtime:1; + unsigned long supports_autosuspend:1; 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) */
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -16,6 +16,7 @@ #include <linux/console.h> #include <linux/gpio/consumer.h> #include <linux/of.h> +#include <linux/pm_runtime.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/device.h> @@ -91,6 +92,27 @@ static inline struct uart_port *uart_port_check(struct uart_state *state) return state->uart_port; } +/* + * Enables runtime PM suspended serial port. If runtime PM is not + * enabled by the serial port driver, only increments the runtime PM + * usage count. May sleep. + */ +static int serial_pm_resume_and_get(struct device *dev) +{ + if (!pm_runtime_enabled(dev)) { + pm_runtime_get_noresume(dev); + return 0; + } + + return pm_runtime_resume_and_get(dev); +} + +static void serial_pm_autosuspend(struct device *dev) +{ + pm_runtime_mark_last_busy(dev); + pm_runtime_put_autosuspend(dev); +} + /* * This routine is used by the interrupt handler to schedule processing in * the software interrupt portion of the driver. @@ -143,13 +165,18 @@ uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear) { unsigned long flags; unsigned int old; + int err; + err = serial_pm_resume_and_get(port->dev); + if (err < 0) + return; spin_lock_irqsave(&port->lock, flags); old = port->mctrl; port->mctrl = (old & ~clear) | set; if (old != port->mctrl) port->ops->set_mctrl(port, port->mctrl); spin_unlock_irqrestore(&port->lock, flags); + serial_pm_autosuspend(port->dev); } #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0) @@ -218,7 +245,12 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state, free_page(page); } + retval = serial_pm_resume_and_get(uport->dev); + if (retval < 0) + goto out; retval = uport->ops->startup(uport); + serial_pm_autosuspend(uport->dev); + if (retval == 0) { if (uart_console(uport) && uport->cons->cflag) { tty->termios.c_cflag = uport->cons->cflag; @@ -244,7 +276,7 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state, */ if (retval && capable(CAP_SYS_ADMIN)) return 1; - +out: return retval; } @@ -481,6 +513,7 @@ static void uart_change_speed(struct tty_struct *tty, struct uart_state *state, struct uart_port *uport = uart_port_check(state); struct ktermios *termios; int hw_stopped; + int err; /* * If we have no tty, termios, or the port does not exist, @@ -490,6 +523,11 @@ static void uart_change_speed(struct tty_struct *tty, struct uart_state *state, return; termios = &tty->termios; + + err = serial_pm_resume_and_get(uport->dev); + if (err < 0) + return; + uport->ops->set_termios(uport, termios, old_termios); /* @@ -518,6 +556,7 @@ static void uart_change_speed(struct tty_struct *tty, struct uart_state *state, __uart_start(tty); } spin_unlock_irq(&uport->lock); + serial_pm_autosuspend(uport->dev); } static int uart_put_char(struct tty_struct *tty, unsigned char c) @@ -1015,7 +1054,14 @@ static int uart_get_lsr_info(struct tty_struct *tty, struct uart_port *uport = uart_port_check(state); unsigned int result; + result = serial_pm_resume_and_get(uport->dev); + if (result < 0) { + result = TIOCSER_TEMT; + goto out; + } + result = uport->ops->tx_empty(uport); + serial_pm_autosuspend(uport->dev); /* * If we're about to load something into the transmit @@ -1027,7 +1073,7 @@ static int uart_get_lsr_info(struct tty_struct *tty, ((uart_circ_chars_pending(&state->xmit) > 0) && !uart_tx_stopped(uport))) result &= ~TIOCSER_TEMT; - +out: return put_user(result, value); } @@ -1045,9 +1091,14 @@ static int uart_tiocmget(struct tty_struct *tty) if (!tty_io_error(tty)) { result = uport->mctrl; + + result = serial_pm_resume_and_get(uport->dev); + if (result < 0) + goto out; spin_lock_irq(&uport->lock); result |= uport->ops->get_mctrl(uport); spin_unlock_irq(&uport->lock); + serial_pm_autosuspend(uport->dev); } out: mutex_unlock(&port->mutex); @@ -1088,8 +1139,12 @@ static int uart_break_ctl(struct tty_struct *tty, int break_state) if (!uport) goto out; + ret = serial_pm_resume_and_get(uport->dev); + if (ret < 0) + goto out; if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl) uport->ops->break_ctl(uport, break_state); + serial_pm_autosuspend(uport->dev); ret = 0; out: mutex_unlock(&port->mutex); @@ -1138,7 +1193,11 @@ static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state) * This will claim the ports resources if * a port is found. */ + ret = serial_pm_resume_and_get(uport->dev); + if (ret < 0) + goto out; uport->ops->config_port(uport, flags); + serial_pm_autosuspend(uport->dev); ret = uart_startup(tty, state, 1); if (ret == 0) @@ -1443,14 +1502,21 @@ static void uart_set_ldisc(struct tty_struct *tty) struct uart_state *state = tty->driver_data; struct uart_port *uport; struct tty_port *port = &state->port; + int err; if (!tty_port_initialized(port)) return; mutex_lock(&state->port.mutex); uport = uart_port_check(state); - if (uport && uport->ops->set_ldisc) + if (uport && uport->ops->set_ldisc) { + err = serial_pm_resume_and_get(uport->dev); + if (err < 0) + goto out; uport->ops->set_ldisc(uport, &tty->termios); + serial_pm_autosuspend(uport->dev); + } +out: mutex_unlock(&state->port.mutex); } @@ -1542,6 +1608,7 @@ static void uart_tty_port_shutdown(struct tty_port *port) { struct uart_state *state = container_of(port, struct uart_state, port); struct uart_port *uport = uart_port_check(state); + int err; /* * At this point, we stop accepting input. To do this, we @@ -1550,9 +1617,13 @@ static void uart_tty_port_shutdown(struct tty_port *port) if (WARN(!uport, "detached port still initialized!\n")) return; + err = serial_pm_resume_and_get(uport->dev); + if (err < 0) + return; spin_lock_irq(&uport->lock); uport->ops->stop_rx(uport); spin_unlock_irq(&uport->lock); + serial_pm_autosuspend(uport->dev); uart_port_shutdown(port); @@ -1668,6 +1739,7 @@ static void uart_port_shutdown(struct tty_port *port) { struct uart_state *state = container_of(port, struct uart_state, port); struct uart_port *uport = uart_port_check(state); + int err; /* * clear delta_msr_wait queue to avoid mem leaks: we may free @@ -1681,8 +1753,13 @@ static void uart_port_shutdown(struct tty_port *port) /* * Free the IRQ and disable the port. */ - if (uport) + if (uport) { + err = serial_pm_resume_and_get(uport->dev); + if (err < 0) + return; uport->ops->shutdown(uport); + serial_pm_autosuspend(uport->dev); + } /* * Ensure that the IRQ handler isn't running on another CPU. @@ -1803,7 +1880,7 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i) struct uart_port *uport; char stat_buf[32]; unsigned int status; - int mmio; + int mmio, err; mutex_lock(&port->mutex); uport = uart_port_check(state); @@ -1824,12 +1901,16 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i) } if (capable(CAP_SYS_ADMIN)) { + err = serial_pm_resume_and_get(uport->dev); + if (err < 0) + goto out; pm_state = state->pm_state; if (pm_state != UART_PM_STATE_ON) uart_change_pm(state, UART_PM_STATE_ON); spin_lock_irq(&uport->lock); status = uport->ops->get_mctrl(uport); spin_unlock_irq(&uport->lock); + serial_pm_autosuspend(uport->dev); if (pm_state != UART_PM_STATE_ON) uart_change_pm(state, pm_state); @@ -2050,6 +2131,7 @@ uart_set_options(struct uart_port *port, struct console *co, { struct ktermios termios; static struct ktermios dummy; + int ret; /* * Ensure that the serial-console lock is initialised early. @@ -2089,7 +2171,17 @@ uart_set_options(struct uart_port *port, struct console *co, */ port->mctrl |= TIOCM_DTR; - port->ops->set_termios(port, &termios, &dummy); + /* At early stage device is not created yet, we can't do PM */ + if (port->dev) { + ret = serial_pm_resume_and_get(port->dev); + if (ret < 0) + return ret; + port->ops->set_termios(port, &termios, &dummy); + serial_pm_autosuspend(port->dev); + } else { + port->ops->set_termios(port, &termios, &dummy); + } + /* * Allow the setting of the UART parameters with a NULL console * too: @@ -2143,6 +2235,7 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) struct tty_port *port = &state->port; struct device *tty_dev; struct uart_match match = {uport, drv}; + int err; mutex_lock(&port->mutex); @@ -2168,11 +2261,15 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) tty_port_set_suspended(port, 1); tty_port_set_initialized(port, 0); + err = serial_pm_resume_and_get(uport->dev); + if (err < 0) + goto unlock; spin_lock_irq(&uport->lock); ops->stop_tx(uport); ops->set_mctrl(uport, 0); ops->stop_rx(uport); spin_unlock_irq(&uport->lock); + serial_pm_autosuspend(uport->dev); /* * Wait for the transmitter to empty. @@ -2183,7 +2280,11 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) dev_err(uport->dev, "%s: Unable to drain transmitter\n", uport->name); + err = serial_pm_resume_and_get(uport->dev); + if (err < 0) + goto unlock; ops->shutdown(uport); + serial_pm_autosuspend(uport->dev); } /* @@ -2206,6 +2307,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) struct device *tty_dev; struct uart_match match = {uport, drv}; struct ktermios termios; + int ret; mutex_lock(&port->mutex); @@ -2236,33 +2338,50 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) if (port->tty && termios.c_cflag == 0) termios = port->tty->termios; + ret = serial_pm_resume_and_get(uport->dev); + if (ret < 0) + goto unlock; if (console_suspend_enabled) uart_change_pm(state, UART_PM_STATE_ON); uport->ops->set_termios(uport, &termios, NULL); + serial_pm_autosuspend(uport->dev); + if (console_suspend_enabled) console_start(uport->cons); } if (tty_port_suspended(port)) { const struct uart_ops *ops = uport->ops; - int ret; + ret = serial_pm_resume_and_get(uport->dev); + if (ret < 0) + goto unlock; uart_change_pm(state, UART_PM_STATE_ON); spin_lock_irq(&uport->lock); ops->set_mctrl(uport, 0); spin_unlock_irq(&uport->lock); + serial_pm_autosuspend(uport->dev); + if (console_suspend_enabled || !uart_console(uport)) { /* Protected by port mutex for now */ struct tty_struct *tty = port->tty; + ret = serial_pm_resume_and_get(uport->dev); + if (ret < 0) + goto unlock; ret = ops->startup(uport); + serial_pm_autosuspend(uport->dev); if (ret == 0) { if (tty) uart_change_speed(tty, state, NULL); + ret = serial_pm_resume_and_get(uport->dev); + if (ret < 0) + goto unlock; spin_lock_irq(&uport->lock); ops->set_mctrl(uport, uport->mctrl); ops->start_tx(uport); spin_unlock_irq(&uport->lock); + serial_pm_autosuspend(uport->dev); tty_port_set_initialized(port, 1); } else { /* @@ -2276,10 +2395,10 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) tty_port_set_suspended(port, 0); } - +unlock: mutex_unlock(&port->mutex); - return 0; + return ret; } static inline void @@ -2329,6 +2448,7 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, struct uart_port *port) { unsigned int flags; + int err; /* * If there isn't a port here, don't do anything further. @@ -2356,6 +2476,10 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, uart_report_port(drv, port); + err = serial_pm_resume_and_get(port->dev); + if (err < 0) + return; + /* Power up port for set_mctrl() */ uart_change_pm(state, UART_PM_STATE_ON); @@ -2367,6 +2491,7 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, spin_lock_irqsave(&port->lock, flags); port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR); spin_unlock_irqrestore(&port->lock, flags); + serial_pm_autosuspend(port->dev); /* * If this driver supports console, and it hasn't been @@ -3084,11 +3209,16 @@ EXPORT_SYMBOL_GPL(uart_handle_dcd_change); */ void uart_handle_cts_change(struct uart_port *uport, unsigned int status) { + int err; + lockdep_assert_held_once(&uport->lock); uport->icount.cts++; if (uart_softcts_mode(uport)) { + err = serial_pm_resume_and_get(uport->dev); + if (err < 0) + return; if (uport->hw_stopped) { if (status) { uport->hw_stopped = 0; @@ -3101,7 +3231,7 @@ void uart_handle_cts_change(struct uart_port *uport, unsigned int status) uport->ops->stop_tx(uport); } } - + serial_pm_autosuspend(uport->dev); } } EXPORT_SYMBOL_GPL(uart_handle_cts_change);