Re: [PATCH v2 1/6] serial: imx: only set DMA rx-ing when DMA starts

From: Uwe Kleine-König
Date: Wed Jul 05 2017 - 09:29:30 EST


On Wed, Jul 05, 2017 at 03:07:01PM +0200, Romain Perier wrote:
> From: Nandor Han <nandor.han@xxxxxx>
> Avoid the situation when `dma_is_rxing` could incorrectly signal that
> DMA RX channel is receiving data in case DMA preparation or sg mapping
> fails.
> This commit fixes the issues by moving the assignment of dma_is_rxing
> out of imx_disable_rx_int(), then the variable is set to 1 from
> start_rx_dma() only when the preparation is correctly done.

I'd write:

There are a few issues with setting dma_is_rxing to 1 in

- Currently always after imx_disable_rx_int() the function
start_rx_dma() is called. This dependency isn't obvious though.
- start_rx_dma() does error checking and might exit without enabling
DMA but keeping dma_is_rxing 1.

So the more natural place for setting dma_is_rxing to 1 is in
start_rx_dma after all errors are checked.

If you use this, there is nothing left of Nandor Han's patch and you can
drop his authorship.

Best regards

Pengutronix e.K. | Uwe Kleine-König |
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