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MIPS: SEAD3: Probe UARTs using DT

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Probe the UARTs on SEAD3 boards using device tree rather than platform
code, in order to reduce the amount of the latter. This requires that
CONFIG_SERIAL_OF_PLATFORM be enabled, so enable it in sead3_defconfig.
The SEAD3 DT shim code is extended to read bootloader environment
variables to determine the appropriate UART & mode for kernel console
output & set the stdout-path property of the chosen node accordingly.

In contrast to the old platform code, which appears to have only ever
set "console=ttyS0,38400n8r" with the code in console_config never
having an effect, this will honor the "yamontty" environment variable to
select between the 2 UARTs on the board and then check the "modetty0" or
"modetty1" variable as appropriate to determine the UART configuration.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14048/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton
2016-08-26 15:17:35 +01:00
committed by Ralf Baechle
parent b6d5e47e67
commit c11e3b48db
6 changed files with 143 additions and 81 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
arch/mips/boot/dts/mti/sead3.dts
View File

@@ -12,6 +12,15 @@
compatible = "mti,sead-3";
interrupt-parent = <&gic>;
chosen {
stdout-path = "uart1:115200";
};
aliases {
uart0 = &uart0;
uart1 = &uart1;
};
cpus {
cpu@0 {
compatible = "mti,mips14KEc", "mti,mips14Kc";
@@ -50,4 +59,32 @@
interrupts = <GIC_LOCAL 1 IRQ_TYPE_NONE>;
};
};
/* UART connected to FTDI & miniUSB socket */
uart0: uart@1f000900 {
compatible = "ns16550a";
reg = <0x1f000900 0x20>;
reg-io-width = <4>;
reg-shift = <2>;
clock-frequency = <14745600>;
interrupts = <3>; /* GIC 3 or CPU 4 */
no-loopback-test;
};
/* UART connected to RS232 socket */
uart1: uart@1f000800 {
compatible = "ns16550a";
reg = <0x1f000800 0x20>;
reg-io-width = <4>;
reg-shift = <2>;
clock-frequency = <14745600>;
interrupts = <2>; /* GIC 2 or CPU 4 */
no-loopback-test;
};
};