Commit 0d114e9f authored by Valentin Caron's avatar Valentin Caron Committed by Greg Kroah-Hartman
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serial: stm32: move dma_request_chan() before clk_prepare_enable() 



If dma_request_chan() returns a PROBE_DEFER error, clk_disable_unprepare()
will be called and USART clock will be disabled. But early console can be
still active on the same USART.

While moving dma_request_chan() before clk_prepare_enable(), the clock
won't be taken in case of a DMA PROBE_DEFER error, and so it doesn't need
to be disabled. Then USART is still clocked for early console.

Fixes: a7770a4b ("serial: stm32: defer probe for dma devices")
Reported-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarValentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20221118170602.1057863-1-valentin.caron@foss.st.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b30e6686

drivers/tty/serial/stm32-usart.c

+23 −24
Original line number Diff line number Diff line
@@ -1680,22 +1680,10 @@ static int stm32_usart_serial_probe(struct platform_device *pdev) 
	if (!stm32port->info)

		return -EINVAL;



	ret = stm32_usart_init_port(stm32port, pdev);

	if (ret)

		return ret;



	if (stm32port->wakeup_src) {

		device_set_wakeup_capable(&pdev->dev, true);

		ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq);

		if (ret)

			goto err_deinit_port;

	}



	stm32port->rx_ch = dma_request_chan(&pdev->dev, "rx");

	if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER) {

		ret = -EPROBE_DEFER;

		goto err_wakeirq;

	}

	if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER)

		return -EPROBE_DEFER;



	/* Fall back in interrupt mode for any non-deferral error */

	if (IS_ERR(stm32port->rx_ch))

		stm32port->rx_ch = NULL;
@@ -1709,6 +1697,17 @@ static int stm32_usart_serial_probe(struct platform_device *pdev) 
	if (IS_ERR(stm32port->tx_ch))

		stm32port->tx_ch = NULL;



	ret = stm32_usart_init_port(stm32port, pdev);

	if (ret)

		goto err_dma_tx;



	if (stm32port->wakeup_src) {

		device_set_wakeup_capable(&pdev->dev, true);

		ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq);

		if (ret)

			goto err_deinit_port;

	}



	if (stm32port->rx_ch && stm32_usart_of_dma_rx_probe(stm32port, pdev)) {

		/* Fall back in interrupt mode */

		dma_release_channel(stm32port->rx_ch);
@@ -1745,19 +1744,11 @@ static int stm32_usart_serial_probe(struct platform_device *pdev) 
	pm_runtime_set_suspended(&pdev->dev);

	pm_runtime_put_noidle(&pdev->dev);



	if (stm32port->tx_ch) {

	if (stm32port->tx_ch)

		stm32_usart_of_dma_tx_remove(stm32port, pdev);

		dma_release_channel(stm32port->tx_ch);

	}



	if (stm32port->rx_ch)

		stm32_usart_of_dma_rx_remove(stm32port, pdev);



err_dma_rx:

	if (stm32port->rx_ch)

		dma_release_channel(stm32port->rx_ch);



err_wakeirq:

	if (stm32port->wakeup_src)

		dev_pm_clear_wake_irq(&pdev->dev);
@@ -1767,6 +1758,14 @@ static int stm32_usart_serial_probe(struct platform_device *pdev) 


	stm32_usart_deinit_port(stm32port);



err_dma_tx:

	if (stm32port->tx_ch)

		dma_release_channel(stm32port->tx_ch);



err_dma_rx:

	if (stm32port->rx_ch)

		dma_release_channel(stm32port->rx_ch);



	return ret;

}