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serial: stm32: move dma_request_chan() before clk_prepare_enable()

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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: a7770a4bfc ("serial: stm32: defer probe for dma devices")
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20221118170602.1057863-1-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Valentin Caron 2022-11-18 18:06:02 +01:00 committed by Greg Kroah-Hartman
parent b30e66863c
commit 0d114e9ff9
1 changed files with 23 additions and 24 deletions
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47
drivers/tty/serial/stm32-usart.c
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@ -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 @@ err_port:
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 @@ err_deinit_port:
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;
}