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serial: 8250: 8250_omap: Do not start RX DMA on THRI interrupt

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commit c6bb057418876cdfdd29a6f7b8cef54539ee8811 upstream.

Starting RX DMA on THRI interrupt is too early because TX may not have
finished yet.

This change is inspired by commit 90b8596ac460 ("serial: 8250: Prevent
starting up DMA Rx on THRI interrupt") and fixes DMA issues I had with
an AM62 SoC that is using the 8250 OMAP variant.

Cc: stable@vger.kernel.org
Fixes: c26389f998a8 ("serial: 8250: 8250_omap: Add DMA support for UARTs on K3 SoCs")
Signed-off-by: Ronald Wahl <ronald.wahl@raritan.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20231101171431.16495-1-rwahl@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ronald Wahl 2023-11-01 18:14:31 +01:00 • committed by Ksawlii
parent 1716cad60a
commit 5439f9c255
1 changed files with 6 additions and 4 deletions
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10
drivers/tty/serial/8250/8250_omap.c
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@ -1209,10 +1209,12 @@ static int omap_8250_dma_handle_irq(struct uart_port *port)
status = serial_port_in(port, UART_LSR); status = serial_port_in(port, UART_LSR);
if (priv->habit & UART_HAS_EFR2) if ((iir & 0x3f) != UART_IIR_THRI) {
am654_8250_handle_rx_dma(up, iir, status); if (priv->habit & UART_HAS_EFR2)
else am654_8250_handle_rx_dma(up, iir, status);
status = omap_8250_handle_rx_dma(up, iir, status); else
status = omap_8250_handle_rx_dma(up, iir, status);
}
serial8250_modem_status(up); serial8250_modem_status(up);
if (status & UART_LSR_THRE && up->dma->tx_err) { if (status & UART_LSR_THRE && up->dma->tx_err) {