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Date:   Tue, 27 Jul 2021 14:49:44 +0300
From:   Andy Shevchenko <andriy.shevchenko@intel.com>
To:     Tony Lindgren <tony@atomide.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-serial@vger.kernel.org, linux-omap@vger.kernel.org,
        linux-kernel@vger.kernel.org, Dario Binacchi <dariobin@libero.it>
Subject: Re: [PATCH 1/2] serial: omap: Disable PM runtime autoidle to remove
 pm_runtime_irq_safe()
Message-ID: <YP/y2KqIcspll/6R@smile.fi.intel.com>
References: <20210727103149.51175-1-tony@atomide.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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In-Reply-To: <20210727103149.51175-1-tony@atomide.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
Precedence: bulk

On Tue, Jul 27, 2021 at 01:31:48PM +0300, Tony Lindgren wrote:
> We want to remove the use of pm_runtime_irq_safe() from serial drivers
> to allow making PM runtime handling generic. Let's simplify things by
> disabling PM runtime autoidle for omap-serial as this driver has been
> deprecated for years because of the 8250_omap driver.
> 
> There are still some omap-serial users that seem to hang on to it for
> some unknown rs485 reasons it seems. But presumably those folks do not
> need PM runtime autoidle with omap-serial, and hopefully can just move
> to using 8250_omap driver instead.
> 
> For 8250_omap driver, we will eventually move to use generic serial
> layer PM based on patches done by Andy Shevchenko to remove
> pm_runtime_irq_safe() usage.

Great one, thanks for doing this, Tony!
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>

> Cc: Andy Shevchenko <andriy.shevchenko@intel.com>
> Cc: Dario Binacchi <dariobin@libero.it>
> Cc: Vignesh Raghavendra <vigneshr@ti.com>
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
>  drivers/tty/serial/omap-serial.c | 75 +-------------------------------
>  1 file changed, 2 insertions(+), 73 deletions(-)
> 
> diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
> --- a/drivers/tty/serial/omap-serial.c
> +++ b/drivers/tty/serial/omap-serial.c
> @@ -276,11 +276,8 @@ static void serial_omap_enable_ms(struct uart_port *port)
>  
>  	dev_dbg(up->port.dev, "serial_omap_enable_ms+%d\n", up->port.line);
>  
> -	pm_runtime_get_sync(up->dev);
>  	up->ier |= UART_IER_MSI;
>  	serial_out(up, UART_IER, up->ier);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static void serial_omap_stop_tx(struct uart_port *port)
> @@ -288,8 +285,6 @@ static void serial_omap_stop_tx(struct uart_port *port)
>  	struct uart_omap_port *up = to_uart_omap_port(port);
>  	int res;
>  
> -	pm_runtime_get_sync(up->dev);
> -
>  	/* Handle RS-485 */
>  	if (port->rs485.flags & SER_RS485_ENABLED) {
>  		if (up->scr & OMAP_UART_SCR_TX_EMPTY) {
> @@ -330,21 +325,15 @@ static void serial_omap_stop_tx(struct uart_port *port)
>  		up->ier &= ~UART_IER_THRI;
>  		serial_out(up, UART_IER, up->ier);
>  	}
> -
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static void serial_omap_stop_rx(struct uart_port *port)
>  {
>  	struct uart_omap_port *up = to_uart_omap_port(port);
>  
> -	pm_runtime_get_sync(up->dev);
>  	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
>  	up->port.read_status_mask &= ~UART_LSR_DR;
>  	serial_out(up, UART_IER, up->ier);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static void transmit_chars(struct uart_omap_port *up, unsigned int lsr)
> @@ -399,8 +388,6 @@ static void serial_omap_start_tx(struct uart_port *port)
>  	struct uart_omap_port *up = to_uart_omap_port(port);
>  	int res;
>  
> -	pm_runtime_get_sync(up->dev);
> -
>  	/* Handle RS-485 */
>  	if (port->rs485.flags & SER_RS485_ENABLED) {
>  		/* Fire THR interrupts when FIFO is below trigger level */
> @@ -421,8 +408,6 @@ static void serial_omap_start_tx(struct uart_port *port)
>  		up->rs485_tx_filter_count = 0;
>  
>  	serial_omap_enable_ier_thri(up);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static void serial_omap_throttle(struct uart_port *port)
> @@ -430,13 +415,10 @@ static void serial_omap_throttle(struct uart_port *port)
>  	struct uart_omap_port *up = to_uart_omap_port(port);
>  	unsigned long flags;
>  
> -	pm_runtime_get_sync(up->dev);
>  	spin_lock_irqsave(&up->port.lock, flags);
>  	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
>  	serial_out(up, UART_IER, up->ier);
>  	spin_unlock_irqrestore(&up->port.lock, flags);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static void serial_omap_unthrottle(struct uart_port *port)
> @@ -444,13 +426,10 @@ static void serial_omap_unthrottle(struct uart_port *port)
>  	struct uart_omap_port *up = to_uart_omap_port(port);
>  	unsigned long flags;
>  
> -	pm_runtime_get_sync(up->dev);
>  	spin_lock_irqsave(&up->port.lock, flags);
>  	up->ier |= UART_IER_RLSI | UART_IER_RDI;
>  	serial_out(up, UART_IER, up->ier);
>  	spin_unlock_irqrestore(&up->port.lock, flags);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static unsigned int check_modem_status(struct uart_omap_port *up)
> @@ -576,7 +555,6 @@ static irqreturn_t serial_omap_irq(int irq, void *dev_id)
>  	int max_count = 256;
>  
>  	spin_lock(&up->port.lock);
> -	pm_runtime_get_sync(up->dev);
>  
>  	do {
>  		iir = serial_in(up, UART_IIR);
> @@ -616,8 +594,6 @@ static irqreturn_t serial_omap_irq(int irq, void *dev_id)
>  
>  	tty_flip_buffer_push(&up->port.state->port);
>  
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  	up->port_activity = jiffies;
>  
>  	return ret;
> @@ -629,13 +605,11 @@ static unsigned int serial_omap_tx_empty(struct uart_port *port)
>  	unsigned long flags;
>  	unsigned int ret = 0;
>  
> -	pm_runtime_get_sync(up->dev);
>  	dev_dbg(up->port.dev, "serial_omap_tx_empty+%d\n", up->port.line);
>  	spin_lock_irqsave(&up->port.lock, flags);
>  	ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
>  	spin_unlock_irqrestore(&up->port.lock, flags);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
> +
>  	return ret;
>  }
>  
> @@ -645,10 +619,7 @@ static unsigned int serial_omap_get_mctrl(struct uart_port *port)
>  	unsigned int status;
>  	unsigned int ret = 0;
>  
> -	pm_runtime_get_sync(up->dev);
>  	status = check_modem_status(up);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  
>  	dev_dbg(up->port.dev, "serial_omap_get_mctrl+%d\n", up->port.line);
>  
> @@ -680,7 +651,6 @@ static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
>  	if (mctrl & TIOCM_LOOP)
>  		mcr |= UART_MCR_LOOP;
>  
> -	pm_runtime_get_sync(up->dev);
>  	old_mcr = serial_in(up, UART_MCR);
>  	old_mcr &= ~(UART_MCR_LOOP | UART_MCR_OUT2 | UART_MCR_OUT1 |
>  		     UART_MCR_DTR | UART_MCR_RTS);
> @@ -696,9 +666,6 @@ static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
>  		up->efr &= ~UART_EFR_RTS;
>  	serial_out(up, UART_EFR, up->efr);
>  	serial_out(up, UART_LCR, lcr);
> -
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static void serial_omap_break_ctl(struct uart_port *port, int break_state)
> @@ -707,7 +674,6 @@ static void serial_omap_break_ctl(struct uart_port *port, int break_state)
>  	unsigned long flags;
>  
>  	dev_dbg(up->port.dev, "serial_omap_break_ctl+%d\n", up->port.line);
> -	pm_runtime_get_sync(up->dev);
>  	spin_lock_irqsave(&up->port.lock, flags);
>  	if (break_state == -1)
>  		up->lcr |= UART_LCR_SBC;
> @@ -715,8 +681,6 @@ static void serial_omap_break_ctl(struct uart_port *port, int break_state)
>  		up->lcr &= ~UART_LCR_SBC;
>  	serial_out(up, UART_LCR, up->lcr);
>  	spin_unlock_irqrestore(&up->port.lock, flags);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static int serial_omap_startup(struct uart_port *port)
> @@ -788,8 +752,6 @@ static int serial_omap_startup(struct uart_port *port)
>  
>  	serial_out(up, UART_OMAP_WER, up->wer);
>  
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  	up->port_activity = jiffies;
>  	return 0;
>  }
> @@ -801,7 +763,6 @@ static void serial_omap_shutdown(struct uart_port *port)
>  
>  	dev_dbg(up->port.dev, "serial_omap_shutdown+%d\n", up->port.line);
>  
> -	pm_runtime_get_sync(up->dev);
>  	/*
>  	 * Disable interrupts from this port
>  	 */
> @@ -825,8 +786,7 @@ static void serial_omap_shutdown(struct uart_port *port)
>  	if (serial_in(up, UART_LSR) & UART_LSR_DR)
>  		(void) serial_in(up, UART_RX);
>  
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
> +	pm_runtime_put_sync(up->dev);
>  	free_irq(up->port.irq, up);
>  	dev_pm_clear_wake_irq(up->dev);
>  }
> @@ -896,7 +856,6 @@ serial_omap_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(up->dev);
>  	spin_lock_irqsave(&up->port.lock, flags);
>  
>  	/*
> @@ -1096,8 +1055,6 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
>  	serial_omap_set_mctrl(&up->port, up->port.mctrl);
>  
>  	spin_unlock_irqrestore(&up->port.lock, flags);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  	dev_dbg(up->port.dev, "serial_omap_set_termios+%d\n", up->port.line);
>  }
>  
> @@ -1110,7 +1067,6 @@ serial_omap_pm(struct uart_port *port, unsigned int state,
>  
>  	dev_dbg(up->port.dev, "serial_omap_pm+%d\n", up->port.line);
>  
> -	pm_runtime_get_sync(up->dev);
>  	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
>  	efr = serial_in(up, UART_EFR);
>  	serial_out(up, UART_EFR, efr | UART_EFR_ECB);
> @@ -1120,9 +1076,6 @@ serial_omap_pm(struct uart_port *port, unsigned int state,
>  	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
>  	serial_out(up, UART_EFR, efr);
>  	serial_out(up, UART_LCR, 0);
> -
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static void serial_omap_release_port(struct uart_port *port)
> @@ -1202,11 +1155,8 @@ static void serial_omap_poll_put_char(struct uart_port *port, unsigned char ch)
>  {
>  	struct uart_omap_port *up = to_uart_omap_port(port);
>  
> -	pm_runtime_get_sync(up->dev);
>  	wait_for_xmitr(up);
>  	serial_out(up, UART_TX, ch);
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  }
>  
>  static int serial_omap_poll_get_char(struct uart_port *port)
> @@ -1214,7 +1164,6 @@ static int serial_omap_poll_get_char(struct uart_port *port)
>  	struct uart_omap_port *up = to_uart_omap_port(port);
>  	unsigned int status;
>  
> -	pm_runtime_get_sync(up->dev);
>  	status = serial_in(up, UART_LSR);
>  	if (!(status & UART_LSR_DR)) {
>  		status = NO_POLL_CHAR;
> @@ -1224,9 +1173,6 @@ static int serial_omap_poll_get_char(struct uart_port *port)
>  	status = serial_in(up, UART_RX);
>  
>  out:
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
> -
>  	return status;
>  }
>  
> @@ -1309,8 +1255,6 @@ serial_omap_console_write(struct console *co, const char *s,
>  	unsigned int ier;
>  	int locked = 1;
>  
> -	pm_runtime_get_sync(up->dev);
> -
>  	local_irq_save(flags);
>  	if (up->port.sysrq)
>  		locked = 0;
> @@ -1343,8 +1287,6 @@ serial_omap_console_write(struct console *co, const char *s,
>  	if (up->msr_saved_flags)
>  		check_modem_status(up);
>  
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  	if (locked)
>  		spin_unlock(&up->port.lock);
>  	local_irq_restore(flags);
> @@ -1403,8 +1345,6 @@ serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485)
>  	unsigned int mode;
>  	int val;
>  
> -	pm_runtime_get_sync(up->dev);
> -
>  	/* Disable interrupts from this port */
>  	mode = up->ier;
>  	up->ier = 0;
> @@ -1438,9 +1378,6 @@ serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485)
>  		serial_out(up, UART_OMAP_SCR, up->scr);
>  	}
>  
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
> -
>  	return 0;
>  }
>  
> @@ -1737,11 +1674,7 @@ static int serial_omap_probe(struct platform_device *pdev)
>  		omap_up_info->autosuspend_timeout = -1;
>  
>  	device_init_wakeup(up->dev, true);
> -	pm_runtime_use_autosuspend(&pdev->dev);
> -	pm_runtime_set_autosuspend_delay(&pdev->dev,
> -			omap_up_info->autosuspend_timeout);
>  
> -	pm_runtime_irq_safe(&pdev->dev);
>  	pm_runtime_enable(&pdev->dev);
>  
>  	pm_runtime_get_sync(&pdev->dev);
> @@ -1755,12 +1688,9 @@ static int serial_omap_probe(struct platform_device *pdev)
>  	if (ret != 0)
>  		goto err_add_port;
>  
> -	pm_runtime_mark_last_busy(up->dev);
> -	pm_runtime_put_autosuspend(up->dev);
>  	return 0;
>  
>  err_add_port:
> -	pm_runtime_dont_use_autosuspend(&pdev->dev);
>  	pm_runtime_put_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  	cpu_latency_qos_remove_request(&up->pm_qos_request);
> @@ -1778,7 +1708,6 @@ static int serial_omap_remove(struct platform_device *dev)
>  
>  	uart_remove_one_port(&serial_omap_reg, &up->port);
>  
> -	pm_runtime_dont_use_autosuspend(up->dev);
>  	pm_runtime_put_sync(up->dev);
>  	pm_runtime_disable(up->dev);
>  	cpu_latency_qos_remove_request(&up->pm_qos_request);
> -- 
> 2.32.0

-- 
With Best Regards,
Andy Shevchenko