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efb362cd93
When this target got updated to 4.14, this patch got removed to re-evaluate if it was still needed. Extensive testing now shows this issue is still present. Let's re-add the patch to fix it for now. As the uart bus is very low bandwidth .. performance impact is negligible. Boot log: [ 22.513051] imx-uart 2020000.serial: DMA transaction error. [ 22.522721] imx-uart 2020000.serial: DMA transaction error. As a sidenote: The patch mentiones an issue with RS485, but the bootlog errors above were recorded with the uart ports in standard RS232 mode. Compile/Run-tested on imx6/GW5200 Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
24 lines
747 B
Diff
24 lines
747 B
Diff
Based on following upstream patch by Tim Harvey (Gateworks):
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https://github.com/Gateworks/openwrt/commit/80a01b6582f94c4547f39d3a25e0a1e9b6eb9877
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TX complete DMA messages are getting missed.
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This is also currently an issue in mainline.
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For now we will disable DMA in serial/imx.c.
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This resolves an issue encountered with RS485 transmit.
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--- a/drivers/tty/serial/imx.c
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+++ b/drivers/tty/serial/imx.c
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@@ -1268,10 +1268,6 @@ static int imx_startup(struct uart_port
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writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
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- /* Can we enable the DMA support? */
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- if (!uart_console(port) && !sport->dma_is_inited)
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- imx_uart_dma_init(sport);
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-
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spin_lock_irqsave(&sport->port.lock, flags);
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/* Reset fifo's and state machines */
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i = 100;
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