ARM: BCM63XX: add low-level UART debug support

Broadcom BCM63xx DSL SoCs have a different UART implementation for which
we need specially crafted low-level debug assembly code to support. Add
support for this using the standard definitions provided in
include/linux/serial_bcm63xx.h (shared with their MIPS counterparts).

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index b11ad54f8d17fa6bfcdc388cbba397814d349bed..07e9dd5eda26520dbb6f0698ed80f6df698c4426 100644 (file)
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -122,6 +122,11 @@ choice
                  mobile SoCs in the Kona family of chips (e.g. bcm28155,
                  bcm11351, etc...)
 
+       config DEBUG_BCM63XX
+               bool "Kernel low-level debugging on BCM63XX UART"
+               depends on ARCH_BCM_63XX
+               select DEBUG_UART_BCM63XX
+
        config DEBUG_BERLIN_UART
                bool "Marvell Berlin SoC Debug UART"
                depends on ARCH_BERLIN
@@ -1038,6 +1043,7 @@ config DEBUG_LL_INCLUDE
        default "debug/vf.S" if DEBUG_VF_UART
        default "debug/vt8500.S" if DEBUG_VT8500_UART0
        default "debug/zynq.S" if DEBUG_ZYNQ_UART0 || DEBUG_ZYNQ_UART1
+       default "debug/bcm63xx.S" if DEBUG_UART_BCM63XX
        default "mach/debug-macro.S"
 
 # Compatibility options for PL01x
@@ -1057,6 +1063,10 @@ config DEBUG_UART_8250
                ARCH_IOP33X || ARCH_IXP4XX || \
                ARCH_LPC32XX || ARCH_MV78XX0 || ARCH_ORION5X || ARCH_RPC
 
+# Compatibility options for BCM63xx
+config DEBUG_UART_BCM63XX
+       def_bool ARCH_BCM_63XX
+
 config DEBUG_UART_PHYS
        hex "Physical base address of debug UART"
        default 0x01c20000 if DEBUG_DAVINCI_DMx_UART0
@@ -1122,11 +1132,13 @@ config DEBUG_UART_PHYS
        default 0xffc02000 if DEBUG_SOCFPGA_UART
        default 0xffd82340 if ARCH_IOP13XX
        default 0xfff36000 if DEBUG_HIGHBANK_UART
+       default 0xfffe8600 if DEBUG_UART_BCM63XX
        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_MSM_UART || DEBUG_QCOM_UARTDM || DEBUG_S3C24XX_UART
+               DEBUG_MSM_UART || DEBUG_QCOM_UARTDM || DEBUG_S3C24XX_UART || \
+               DEBUG_UART_BCM63XX
 
 config DEBUG_UART_VIRT
        hex "Virtual base address of debug UART"
@@ -1157,6 +1169,7 @@ config DEBUG_UART_VIRT
        default 0xfa71e000 if DEBUG_QCOM_UARTDM
        default 0xfb009000 if DEBUG_REALVIEW_STD_PORT
        default 0xfb10c000 if DEBUG_REALVIEW_PB1176_PORT
+       default 0xfcfe8600 if DEBUG_UART_BCM63XX
        default 0xfd000000 if ARCH_SPEAR3XX || ARCH_SPEAR6XX
        default 0xfd000000 if ARCH_SPEAR13XX
        default 0xfd012000 if ARCH_MV78XX0
@@ -1194,7 +1207,8 @@ config DEBUG_UART_VIRT
        default DEBUG_UART_PHYS if !MMU
        depends on DEBUG_LL_UART_8250 || DEBUG_LL_UART_PL01X || \
                DEBUG_UART_8250 || DEBUG_UART_PL01X || \
-               DEBUG_MSM_UART || DEBUG_QCOM_UARTDM || DEBUG_S3C24XX_UART
+               DEBUG_MSM_UART || DEBUG_QCOM_UARTDM || DEBUG_S3C24XX_UART || \
+               DEBUG_UART_BCM63XX
 
 config DEBUG_UART_8250_SHIFT
        int "Register offset shift for the 8250 debug UART"

diff --git a/arch/arm/include/debug/bcm63xx.S b/arch/arm/include/debug/bcm63xx.S
new file mode 100644 (file)
index 0000000..e7164d5
--- /dev/null
+++ b/arch/arm/include/debug/bcm63xx.S
@@ -0,0 +1,33 @@
+/*
+ * Broadcom BCM63xx low-level UART debug
+ *
+ * Copyright (C) 2014 Broadcom Corporation
+ *
+ * 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.
+ */
+
+#include <linux/serial_bcm63xx.h>
+
+       .macro  addruart, rp, rv, tmp
+       ldr     \rp, =CONFIG_DEBUG_UART_PHYS
+       ldr     \rv, =CONFIG_DEBUG_UART_VIRT
+       .endm
+
+       .macro  senduart, rd, rx
+       /* word access do not work */
+       strb    \rd, [\rx, #UART_FIFO_REG]
+       .endm
+
+       .macro  waituart, rd, rx
+1001:  ldr     \rd, [\rx, #UART_IR_REG]
+       tst     \rd, #(1 << UART_IR_TXEMPTY)
+       beq     1001b
+       .endm
+
+       .macro  busyuart, rd, rx
+1002:  ldr     \rd, [\rx, #UART_IR_REG]
+       tst     \rd, #(1 << UART_IR_TXTRESH)
+       beq     1002b
+       .endm