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authorVineet Gupta <vgupta@synopsys.com>2014-10-28 15:04:05 +0530
committerVineet Gupta <vgupta@synopsys.com>2015-02-02 17:08:37 +0530
commitffb7fcd66f14bc716b9fdf559e71909131fef39b (patch)
tree35b7c289c75651d8244ac0e7d7ede0185da1f367 /arch/arc/kernel/devtree.c
parent7bf6df575fd628fd7ec737789ae8bcb7081d77de (diff)
downloadtalos-obmc-linux-ffb7fcd66f14bc716b9fdf559e71909131fef39b.tar.gz
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ARC: Dynamically determine BASE_BAUD from DeviceTree
8250 earlycon is broken on multi-platform ARC because the UART clk value (BASE_BAUD) is fixed at build time. Instead, determine the appropriate UART clk at runtime; parse the devicetree early for platforms requiring alternate UART clk values (currently only the TB10X platform). Cc: Jiri Slaby <jslaby@suse.cz> Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Rob Herring <robh@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/kernel/devtree.c')
-rw-r--r--arch/arc/kernel/devtree.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/arc/kernel/devtree.c b/arch/arc/kernel/devtree.c
index fffdb5e41b20..5036d4c06996 100644
--- a/arch/arc/kernel/devtree.c
+++ b/arch/arc/kernel/devtree.c
@@ -17,6 +17,28 @@
#include <asm/clk.h>
#include <asm/mach_desc.h>
+#ifdef CONFIG_SERIAL_8250_CONSOLE
+
+static unsigned int __initdata arc_base_baud;
+
+unsigned int __init arc_early_base_baud(void)
+{
+ return arc_base_baud/16;
+}
+
+static void __init arc_set_early_base_baud(unsigned long dt_root)
+{
+ unsigned int core_clk = arc_get_core_freq();
+
+ if (of_flat_dt_is_compatible(dt_root, "abilis,arc-tb10x"))
+ arc_base_baud = core_clk/3;
+ else
+ arc_base_baud = core_clk;
+}
+#else
+#define arc_set_early_base_baud(dt_root)
+#endif
+
static const void * __init arch_get_next_mach(const char *const **match)
{
static const struct machine_desc *mdesc = __arch_info_begin;
@@ -56,5 +78,7 @@ const struct machine_desc * __init setup_machine_fdt(void *dt)
if (clk)
arc_set_core_freq(of_read_ulong(clk, len/4));
+ arc_set_early_base_baud(dt_root);
+
return mdesc;
}
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