[PATCH 7/7] serial: 8250_port: Remove calls to runtime PM
From: Tony Lindgren
Date: Mon Nov 15 2021 - 03:43:51 EST
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Since we now have runtime PM calls in serial_core.c the individual
drivers do not need them anymore for the struct uart_ops related
functions.
Remove runtime PM calls in 8250 driver. This still leaves the flag for
UART_CAP_RPM for serial8250_rpm_get_tx(), serial8250_rpm_put_tx() and
serial8250_wakeup() to manage the reference count for serial TX.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
[tony@xxxxxxxxxxx: updated to remove the exported functions too]
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
---
drivers/tty/serial/8250/8250.h | 3 -
drivers/tty/serial/8250/8250_port.c | 98 ++++++++---------------------
2 files changed, 27 insertions(+), 74 deletions(-)
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -152,9 +152,6 @@ static inline bool serial8250_clear_THRI(struct uart_8250_port *up)
struct uart_8250_port *serial8250_get_port(int line);
-void serial8250_rpm_get(struct uart_8250_port *p);
-void serial8250_rpm_put(struct uart_8250_port *p);
-
void serial8250_rpm_get_tx(struct uart_8250_port *p);
void serial8250_rpm_put_tx(struct uart_8250_port *p);
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -573,23 +573,6 @@ void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p)
}
EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos);
-void serial8250_rpm_get(struct uart_8250_port *p)
-{
- if (!(p->capabilities & UART_CAP_RPM))
- return;
- pm_runtime_get_sync(p->port.dev);
-}
-EXPORT_SYMBOL_GPL(serial8250_rpm_get);
-
-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);
-}
-EXPORT_SYMBOL_GPL(serial8250_rpm_put);
-
/**
* serial8250_em485_init() - put uart_8250_port into rs485 emulating
* @p: uart_8250_port port instance
@@ -724,7 +707,14 @@ void serial8250_rpm_get_tx(struct uart_8250_port *p)
rpm_active = xchg(&p->rpm_tx_active, 1);
if (rpm_active)
return;
- pm_runtime_get(p->port.dev);
+
+ /*
+ * Device has to be powered on at this point. Here we just increase
+ * reference count to prevent autosuspend until the TX FIFO becomes
+ * empty. Paired with serial8250_rpm_put_tx(). See also a comment
+ * in serial8250_tx_chars().
+ */
+ pm_runtime_get_noresume(p->port.dev);
}
EXPORT_SYMBOL_GPL(serial8250_rpm_get_tx);
@@ -752,8 +742,6 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
{
unsigned char lcr = 0, efr = 0;
- serial8250_rpm_get(p);
-
if (p->capabilities & UART_CAP_SLEEP) {
if (p->capabilities & UART_CAP_EFR) {
lcr = serial_in(p, UART_LCR);
@@ -769,8 +757,6 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
serial_out(p, UART_LCR, lcr);
}
}
-
- serial8250_rpm_put(p);
}
#ifdef CONFIG_SERIAL_8250_RSA
@@ -1432,13 +1418,9 @@ 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 | UART_IER_RDI);
up->port.read_status_mask &= ~UART_LSR_DR;
serial_port_out(port, UART_IER, up->ier);
-
- serial8250_rpm_put(up);
}
/**
@@ -1477,8 +1459,11 @@ static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
stop_tx_timer);
struct uart_8250_port *p = em485->port;
unsigned long flags;
+ int err;
- serial8250_rpm_get(p);
+ err = pm_runtime_resume_and_get(p->port.dev);
+ if (err < 0)
+ goto out_rpm_err;
spin_lock_irqsave(&p->port.lock, flags);
if (em485->active_timer == &em485->stop_tx_timer) {
p->rs485_stop_tx(p);
@@ -1486,8 +1471,9 @@ static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
em485->tx_stopped = true;
}
spin_unlock_irqrestore(&p->port.lock, flags);
- serial8250_rpm_put(p);
-
+ pm_runtime_mark_last_busy(p->port.dev);
+ pm_runtime_put_autosuspend(p->port.dev);
+out_rpm_err:
return HRTIMER_NORESTART;
}
@@ -1545,7 +1531,6 @@ 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);
/*
@@ -1555,7 +1540,6 @@ 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 inline void __start_tx(struct uart_port *port)
@@ -1703,9 +1687,7 @@ static void serial8250_enable_ms(struct uart_port *port)
up->ier |= UART_IER_MSI;
- serial8250_rpm_get(up);
serial_port_out(port, UART_IER, up->ier);
- serial8250_rpm_put(up);
}
void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
@@ -1984,15 +1966,11 @@ 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;
}
@@ -2002,9 +1980,7 @@ unsigned int serial8250_do_get_mctrl(struct uart_port *port)
unsigned int status;
unsigned int val;
- serial8250_rpm_get(up);
status = serial8250_modem_status(up);
- serial8250_rpm_put(up);
val = serial8250_MSR_to_TIOCM(status);
if (up->gpios)
@@ -2054,7 +2030,6 @@ 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;
@@ -2062,7 +2037,6 @@ 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);
}
/*
@@ -2107,33 +2081,21 @@ static void wait_for_xmitr(struct uart_8250_port *up, int bits)
static int serial8250_get_poll_char(struct uart_port *port)
{
- 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;
- }
-
- status = serial_port_in(port, UART_RX);
-out:
- serial8250_rpm_put(up);
- return status;
+ return serial_port_in(port, UART_RX);
}
-
static void serial8250_put_poll_char(struct uart_port *port,
unsigned char c)
{
unsigned int ier;
struct uart_8250_port *up = up_to_u8250p(port);
- serial8250_rpm_get(up);
/*
* First save the IER then disable the interrupts
*/
@@ -2155,7 +2117,6 @@ 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 */
@@ -2178,7 +2139,6 @@ 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;
@@ -2244,8 +2204,7 @@ int serial8250_do_startup(struct uart_port *port)
if (!(port->flags & UPF_BUGGY_UART) &&
(serial_port_in(port, UART_LSR) == 0xff)) {
dev_info_ratelimited(port->dev, "LSR safety check engaged!\n");
- retval = -ENODEV;
- goto out;
+ return -ENODEV;
}
/*
@@ -2333,7 +2292,7 @@ int serial8250_do_startup(struct uart_port *port)
retval = up->ops->setup_irq(up);
if (retval)
- goto out;
+ return retval;
/*
* Now, initialize the UART
@@ -2432,10 +2391,7 @@ int serial8250_do_startup(struct uart_port *port)
outb_p(0x80, icp);
inb_p(icp);
}
- retval = 0;
-out:
- serial8250_rpm_put(up);
- return retval;
+ return 0;
}
EXPORT_SYMBOL_GPL(serial8250_do_startup);
@@ -2451,7 +2407,6 @@ 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
*/
@@ -2495,7 +2450,6 @@ void serial8250_do_shutdown(struct uart_port *port)
* the IRQ chain.
*/
serial_port_in(port, UART_RX);
- serial8250_rpm_put(up);
up->ops->release_irq(up);
}
@@ -2737,6 +2691,7 @@ void serial8250_update_uartclk(struct uart_port *port, unsigned int uartclk)
unsigned int baud, quot, frac = 0;
struct ktermios *termios;
unsigned long flags;
+ int err;
mutex_lock(&port->state->port.mutex);
@@ -2753,7 +2708,9 @@ void serial8250_update_uartclk(struct uart_port *port, unsigned int uartclk)
baud = serial8250_get_baud_rate(port, termios, NULL);
quot = serial8250_get_divisor(port, baud, &frac);
- serial8250_rpm_get(up);
+ err = pm_runtime_resume_and_get(port->dev);
+ if (err < 0)
+ goto out_lock;
spin_lock_irqsave(&port->lock, flags);
uart_update_timeout(port, termios->c_cflag, baud);
@@ -2762,7 +2719,8 @@ void serial8250_update_uartclk(struct uart_port *port, unsigned int uartclk)
serial_port_out(port, UART_LCR, up->lcr);
spin_unlock_irqrestore(&port->lock, flags);
- serial8250_rpm_put(up);
+ pm_runtime_mark_last_busy(port->dev);
+ pm_runtime_put_autosuspend(port->dev);
out_lock:
mutex_unlock(&port->state->port.mutex);
@@ -2793,7 +2751,6 @@ 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);
up->lcr = cval; /* Save computed LCR */
@@ -2899,7 +2856,6 @@ 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))
--
2.33.1