From: Vineet Gupta <vgupta@xxxxxxxxxxxx>
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 <vgupta@xxxxxxxxxxxx>
---
Documentation/devicetree/bindings/arc/axs10x.txt | 2 +-
arch/arc/boot/dts/axs101.dts | 4 ++--
arch/arc/kernel/devtree.c | 2 ++
3 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/Documentation/devicetree/bindings/arc/axs10x.txt b/Documentation/devicetree/bindings/arc/axs10x.txt
index dcbb834..9021ab7 100644
--- a/Documentation/devicetree/bindings/arc/axs10x.txt
+++ b/Documentation/devicetree/bindings/arc/axs10x.txt
@@ -4,4 +4,4 @@ Synopsys DesignWare ARC Software Development Platforms Device Tree Bindings
SDP boards with Synopsys ARC700 core shall have the following properties.
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;
}
--
2.1.0
--
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