ARM: meson: debug: add debug UART for earlyprintk support

Add the UART definitions needed to support earlyprintk for MesonX SoCs
on UARTAO.

Signed-off-by: Carlo Caione <carlo@caione.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 35 insertions, 0 deletions

diff --git a/arch/arm/include/debug/meson.S b/arch/arm/include/debug/meson.S
new file mode 100644
index 000000000000..1bae99bf6f11
--- /dev/null
+++ b/arch/arm/include/debug/meson.S
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2014 Carlo Caione
+ * Carlo Caione <carlo@caione.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define MESON_AO_UART_WFIFO             0x0
+#define MESON_AO_UART_STATUS            0xc
+
+#define MESON_AO_UART_TX_FIFO_EMPTY     (1 << 22)
+#define MESON_AO_UART_TX_FIFO_FULL      (1 << 21)
+
+        .macro  addruart, rp, rv, tmp
+        ldr     \rp, =(CONFIG_DEBUG_UART_PHYS)          @ physical
+        ldr     \rv, =(CONFIG_DEBUG_UART_VIRT)          @ virtual
+        .endm
+
+        .macro  senduart,rd,rx
+        str     \rd, [\rx, #MESON_AO_UART_WFIFO]
+        .endm
+
+        .macro  busyuart,rd,rx
+1002:   ldr     \rd, [\rx, #MESON_AO_UART_STATUS]
+        tst     \rd, #MESON_AO_UART_TX_FIFO_EMPTY
+        beq     1002b
+        .endm
+
+        .macro  waituart,rd,rx
+1001:   ldr     \rd, [\rx, #MESON_AO_UART_STATUS]
+        tst     \rd, #MESON_AO_UART_TX_FIFO_FULL
+        bne     1001b
+        .endm