From 8d0d56ba24d8d0b04bc9d9a7fbd1796d8966159f Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Mon, 2 Feb 2015 19:23:21 +0530 Subject: ARC: [axs101] support early 8250 uart Earlycon calculates UART clock as "BASE_BAUD * 16". In case of ARC "BASE_BAUD" is calculated dynamically in runtime, basically it is an alias to arc_early_base_baud(), which in turn just does "arc_base_baud/16". 8250 UART on AXS/SDP board uses 33.3MHz clock source which is set in "arc_base_baud" with this change. Additional compatibility string "snps,arc-sdp" is introduced as well because there're different flavours of AXS boards but they all share the same motherboard and so it's possible to re-use the same code for motherbord even if CPU daughterboard changes. Signed-off-by: Vineet Gupta diff --git a/Documentation/devicetree/bindings/arc/axs101.txt b/Documentation/devicetree/bindings/arc/axs101.txt index 568aa5f..48290d5 100644 --- a/Documentation/devicetree/bindings/arc/axs101.txt +++ b/Documentation/devicetree/bindings/arc/axs101.txt @@ -4,4 +4,4 @@ Synopsys DesignWare ARC Software Development Platforms Device Tree Bindings SDP Main Board with an AXC001 CPU Card hoisting ARC700 core in silicon Required root node properties: - - compatible = "snps,axs101"; + - compatible = "snps,axs101", "snps,arc-sdp"; diff --git a/arch/arc/boot/dts/axs101.dts b/arch/arc/boot/dts/axs101.dts index 6c3391d..3f9b058 100644 --- a/arch/arc/boot/dts/axs101.dts +++ b/arch/arc/boot/dts/axs101.dts @@ -13,9 +13,9 @@ /include/ "axs10x_mb.dtsi" / { - compatible = "snps,axs101"; + compatible = "snps,axs101", "snps,arc-sdp"; chosen { - bootargs = "console=tty0 console=ttyS3,115200n8 consoleblank=0"; + bootargs = "earlycon=uart8250,mmio32,0xe0022000,115200n8 console=tty0 console=ttyS3,115200n8 consoleblank=0"; }; }; diff --git a/arch/arc/kernel/devtree.c b/arch/arc/kernel/devtree.c index e32b54a..f801d46 100644 --- a/arch/arc/kernel/devtree.c +++ b/arch/arc/kernel/devtree.c @@ -32,6 +32,8 @@ static void __init arc_set_early_base_baud(unsigned long dt_root) if (of_flat_dt_is_compatible(dt_root, "abilis,arc-tb10x")) arc_base_baud = core_clk/3; + else if (of_flat_dt_is_compatible(dt_root, "snps,arc-sdp")) + arc_base_baud = 33333333; /* Fixed 33MHz clk */ else arc_base_baud = core_clk; } -- cgit v0.10.2