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>

diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index eb3913fd07e707112c245a1a55f079255cfb59fa..2dc9f6cd3c38d222d832c5f87db33966879ff3ad 100644 (file)
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -356,6 +356,13 @@ choice
                  Say Y here if you want the debug print routines to direct
                  their output to UART1 serial port on KEYSTONE2 devices.
 
+       config DEBUG_MESON_UARTAO
+               bool "Kernel low-level debugging via Meson6 UARTAO"
+               depends on ARCH_MESON
+               help
+                 Say Y here if you want kernel low-lever debugging support
+                 on Amlogic Meson6 based platforms on the UARTAO.
+
        config DEBUG_MMP_UART2
                bool "Kernel low-level debugging message via MMP UART2"
                depends on ARCH_MMP
@@ -1027,6 +1034,7 @@ config DEBUG_LL_INCLUDE
        string
        default "debug/8250.S" if DEBUG_LL_UART_8250 || DEBUG_UART_8250
        default "debug/clps711x.S" if DEBUG_CLPS711X_UART1 || DEBUG_CLPS711X_UART2
+       default "debug/meson.S" if DEBUG_MESON_UARTAO
        default "debug/pl01x.S" if DEBUG_LL_UART_PL01X || DEBUG_UART_PL01X
        default "debug/exynos.S" if DEBUG_EXYNOS_UART
        default "debug/efm32.S" if DEBUG_LL_UART_EFM32
@@ -1123,6 +1131,7 @@ config DEBUG_UART_PHYS
        default 0xc8000003 if ARCH_IXP4XX && CPU_BIG_ENDIAN
        default 0xd0000000 if ARCH_SPEAR3XX || ARCH_SPEAR6XX
        default 0xd0012000 if DEBUG_MVEBU_UART
+       default 0xc81004c0 if DEBUG_MESON_UARTAO
        default 0xd4017000 if DEBUG_MMP_UART2
        default 0xd4018000 if DEBUG_MMP_UART3
        default 0xe0000000 if ARCH_SPEAR13XX
@@ -1143,7 +1152,7 @@ config DEBUG_UART_PHYS
        default 0xfffff700 if ARCH_IOP33X
        depends on DEBUG_LL_UART_8250 || DEBUG_LL_UART_PL01X || \
                DEBUG_LL_UART_EFM32 || \
-               DEBUG_UART_8250 || DEBUG_UART_PL01X || \
+               DEBUG_UART_8250 || DEBUG_UART_PL01X || DEBUG_MESON_UARTAO || \
                DEBUG_MSM_UART || DEBUG_QCOM_UARTDM || DEBUG_S3C24XX_UART
 
 config DEBUG_UART_VIRT
@@ -1182,6 +1191,7 @@ config DEBUG_UART_VIRT
        default 0xfd012000 if ARCH_MV78XX0
        default 0xfde12000 if ARCH_DOVE
        default 0xfe012000 if ARCH_ORION5X
+       default 0xf31004c0 if DEBUG_MESON_UARTAO
        default 0xfe017000 if DEBUG_MMP_UART2
        default 0xfe018000 if DEBUG_MMP_UART3
        default 0xfe100000 if DEBUG_IMX23_UART || DEBUG_IMX28_UART
@@ -1213,7 +1223,7 @@ config DEBUG_UART_VIRT
        default 0xff003000 if DEBUG_U300_UART
        default DEBUG_UART_PHYS if !MMU
        depends on DEBUG_LL_UART_8250 || DEBUG_LL_UART_PL01X || \
-               DEBUG_UART_8250 || DEBUG_UART_PL01X || \
+               DEBUG_UART_8250 || DEBUG_UART_PL01X || DEBUG_MESON_UARTAO || \
                DEBUG_MSM_UART || DEBUG_QCOM_UARTDM || DEBUG_S3C24XX_UART
 
 config DEBUG_UART_8250_SHIFT

diff --git a/arch/arm/include/debug/meson.S b/arch/arm/include/debug/meson.S
new file mode 100644 (file)
index 0000000..1bae99b
--- /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