serial: 8250_pxa: Configure tx_loadsz to match FIFO IRQ level

commit 5208e7ced520a813b4f4774451fbac4e517e78b2 upstream.

The FIFO is 64 bytes, but the FCR is configured to fire the TX interrupt
when the FIFO is half empty (bit 3 = 0). Thus, we should only write 32
bytes when a TX interrupt occurs.

This fixes a problem observed on the PXA168 that dropped a bunch of TX
bytes during large transmissions.

Fixes: ab28f51c77cd ("serial: rewrite pxa2xx-uart to use 8250_core")
Signed-off-by: Doug Brown <doug@schmorgal.com>
Link: https://lore.kernel.org/r/20240519191929.122202-1-doug@schmorgal.com
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Doug Brown 2024-05-19 12:19:30 -07:00 committed by Ksawlii
parent 0d21b4485a
commit 8c9519c7da

View file

@ -125,6 +125,7 @@ static int serial_pxa_probe(struct platform_device *pdev)
uart.port.regshift = 2;
uart.port.irq = irq;
uart.port.fifosize = 64;
uart.tx_loadsz = 32;
uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST | UPF_FIXED_TYPE;
uart.port.dev = &pdev->dev;
uart.port.uartclk = clk_get_rate(data->clk);