From: Andy Shevchenko <andriy.shevche...@linux.intel.com>
Backport:
- Upstream-Status: Pending.
- Backport fix.
[https://bitbucket.org/andy-shev/linux/commits/881267aa49844618a01a9d11895b48822e68c1a1?at=master]
Since we have runtime PM calls in serial_core.c the individual drivers do not
need them anymore. Remove unnecessary runtime PM calls.
Signed-off-by: Andy Shevchenko <andriy.shevche...@linux.intel.com>
Signed-off-by: Nilesh Bacchewar <nilesh.bacche...@intel.com>
---
drivers/tty/serial/8250/8250_port.c | 74 +++++++++++++------------------------
1 file changed, 25 insertions(+), 49 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c
b/drivers/tty/serial/8250/8250_port.c
index 805a15c..880fb4c 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -543,7 +543,12 @@ 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_sync(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. See also a comment in serial8250_tx_chars().
+ */
+ pm_runtime_get_noresume(p->port.dev);
}
EXPORT_SYMBOL_GPL(serial8250_rpm_get_tx);
@@ -577,11 +582,10 @@ 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);
- goto out;
+ return;
}
if (p->capabilities & UART_CAP_SLEEP) {
@@ -599,8 +603,6 @@ static void serial8250_set_sleep(struct uart_8250_port *p,
int sleep)
serial_out(p, UART_LCR, lcr);
}
}
-out:
- serial8250_rpm_put(p);
}
#ifdef CONFIG_SERIAL_8250_RSA
@@ -1295,7 +1297,6 @@ 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);
/*
@@ -1305,7 +1306,6 @@ 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 void serial8250_start_tx(struct uart_port *port)
@@ -1353,13 +1353,9 @@ 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);
}
static void serial8250_disable_ms(struct uart_port *port)
@@ -1385,9 +1381,7 @@ 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);
}
/*
@@ -1629,15 +1623,11 @@ 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;
}
@@ -1647,9 +1637,7 @@ 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)
@@ -1698,7 +1686,6 @@ 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;
@@ -1706,7 +1693,6 @@ 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);
}
/*
@@ -1753,21 +1739,12 @@ 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);
}
@@ -1777,7 +1754,6 @@ 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
*/
@@ -1799,7 +1775,6 @@ 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 */
@@ -1822,7 +1797,6 @@ 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;
@@ -1881,8 +1855,7 @@ 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));
- retval = -ENODEV;
- goto out;
+ return -ENODEV;
}
/*
@@ -1945,7 +1918,7 @@ int serial8250_do_startup(struct uart_port *port)
retval = up->ops->setup_irq(up);
if (retval)
- goto out;
+ return retval;
/*
* Now, initialize the UART
@@ -2041,10 +2014,7 @@ dont_test_tx_en:
outb_p(0x80, icp);
inb_p(icp);
}
- retval = 0;
-out:
- serial8250_rpm_put(up);
- return retval;
+ return 0;
}
EXPORT_SYMBOL_GPL(serial8250_do_startup);
@@ -2060,7 +2030,6 @@ 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
*/
@@ -2100,7 +2069,6 @@ 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);
}
@@ -2302,7 +2270,6 @@ 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 */
@@ -2394,7 +2361,6 @@ serial8250_do_set_termios(struct uart_port *port, struct
ktermios *termios,
serial8250_do_restore_context(port);
spin_unlock_irqrestore(&port->lock, flags);
- serial8250_rpm_put(up);
/* Don't rewrite B0 */
if (tty_termios_baud_rate(termios))
@@ -2853,6 +2819,11 @@ static void serial8250_console_restore(struct
uart_8250_port *up)
* any possible real use of the port...
*
* The console_lock must be held when we get here.
+ *
+ * Doing runtime PM is a really bad idea for the kernel console.
+ * Nevertheless we leave the calls here and allow individual drivers to
+ * decide how to proceed.
+ *
*/
void serial8250_console_write(struct uart_8250_port *up, const char *s,
unsigned int count)
@@ -2864,7 +2835,9 @@ void serial8250_console_write(struct uart_8250_port *up,
const char *s,
touch_nmi_watchdog();
- serial8250_rpm_get(up);
+ /* At early stage device is not created yet, we can't do PM */
+ if (port->dev)
+ serial8250_rpm_get(up);
if (port->sysrq)
locked = 0;
@@ -2910,7 +2883,10 @@ void serial8250_console_write(struct uart_8250_port *up,
const char *s,
if (locked)
spin_unlock_irqrestore(&port->lock, flags);
- serial8250_rpm_put(up);
+
+ /* At early stage device is not created yet, we can't do PM */
+ if (port->dev)
+ serial8250_rpm_put(up);
}
static unsigned int probe_baud(struct uart_port *port)
--
1.9.1
--
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