From b7639b0b15ddd1a4686b0142e70dfb122eefc88f Mon Sep 17 00:00:00 2001 From: Joshua Scott Date: Fri, 16 Mar 2018 13:42:00 +1300 Subject: serial: 8250_dw: Limit dw8250_tx_wait_empty quirk to armada-38x devices MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The previous implementation has had a detrimental effect on devices using high bitrates (bluetooth), as the fifo being non-empty for a single check would result in a 10 µs delay. Limit the change to devices with the new "marvell,armada-38x-uart" compatible string. Also update the code to allow the first 1000 retries to not perform a delay. The maximum duration of retries has been increased to cover a worst-case seen on the Armada 385 SoC. "dmesg ; resize", will fill the buffer with text to output before doing a resize. At 9600 baud this took up to 13 ms to flush all characters and avoid some getting lost. Signed-off-by: Joshua Scott Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- arch/arm/boot/dts/armada-38x.dtsi | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/arm/boot/dts/armada-38x.dtsi b/arch/arm/boot/dts/armada-38x.dtsi index 4cc09e43eea2..6916d7532ad2 100644 --- a/arch/arm/boot/dts/armada-38x.dtsi +++ b/arch/arm/boot/dts/armada-38x.dtsi @@ -163,7 +163,7 @@ }; uart0: serial@12000 { - compatible = "snps,dw-apb-uart"; + compatible = "marvell,armada-38x-uart"; reg = <0x12000 0x100>; reg-shift = <2>; interrupts = ; @@ -173,7 +173,7 @@ }; uart1: serial@12100 { - compatible = "snps,dw-apb-uart"; + compatible = "marvell,armada-38x-uart"; reg = <0x12100 0x100>; reg-shift = <2>; interrupts = ; -- cgit v1.2.3-59-g8ed1b