ARM: 7850/1: DEBUG_LL on efm32 SoCs

This implements output of debug messages on efm32 SoCs.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index 9762c84..2b32068 100644 (file)
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -834,6 +834,20 @@ choice
                  options; the platform specific options are deprecated
                  and will be soon removed.
 
+       config DEBUG_LL_UART_EFM32
+               bool "Kernel low-level debugging via efm32 UART"
+               depends on ARCH_EFM32
+               help
+                 Say Y here if you want the debug print routines to direct
+                 their output to an UART or USART port on efm32 based
+                 machines. Use the following addresses for DEBUG_UART_PHYS:
+
+                   0x4000c000 | USART0
+                   0x4000c400 | USART1
+                   0x4000c800 | USART2
+                   0x4000e000 | UART0
+                   0x4000e400 | UART1
+
        config DEBUG_LL_UART_PL01X
                bool "Kernel low-level debugging via ARM Ltd PL01x Primecell UART"
                help
@@ -885,6 +899,7 @@ config DEBUG_LL_INCLUDE
        default "debug/8250.S" if DEBUG_LL_UART_8250 || DEBUG_UART_8250
        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
        default "debug/icedcc.S" if DEBUG_ICEDCC
        default "debug/imx.S" if DEBUG_IMX1_UART || \
                                 DEBUG_IMX25_UART || \
@@ -951,6 +966,7 @@ config DEBUG_UART_PHYS
        default 0x20064000 if DEBUG_RK29_UART1 || DEBUG_RK3X_UART2
        default 0x20068000 if DEBUG_RK29_UART2 || DEBUG_RK3X_UART3
        default 0x20201000 if DEBUG_BCM2835
+       default 0x4000e400 if DEBUG_LL_UART_EFM32
        default 0x40090000 if ARCH_LPC32XX
        default 0x40100000 if DEBUG_PXA_UART1
        default 0x42000000 if ARCH_GEMINI
@@ -981,6 +997,7 @@ config DEBUG_UART_PHYS
        default 0xfff36000 if DEBUG_HIGHBANK_UART
        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
 
 config DEBUG_UART_VIRT

diff --git a/arch/arm/include/debug/efm32.S b/arch/arm/include/debug/efm32.S
new file mode 100644 (file)
index 0000000..2265a19
--- /dev/null
+++ b/arch/arm/include/debug/efm32.S
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2013 Pengutronix
+ * Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
+ *
+ * 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 UARTn_CMD              0x000c
+#define UARTn_CMD_TXEN                 0x0004
+
+#define        UARTn_STATUS            0x0010
+#define        UARTn_STATUS_TXC                0x0020
+#define        UARTn_STATUS_TXBL               0x0040
+
+#define        UARTn_TXDATA            0x0034
+
+               .macro  addruart, rx, tmp
+               ldr     \rx, =(CONFIG_DEBUG_UART_PHYS)
+
+               /*
+                * enable TX. The driver might disable it to save energy. We
+                * don't care about disabling at the end as during debug power
+                * consumption isn't that important.
+                */
+               ldr     \tmp, =(UARTn_CMD_TXEN)
+               str     \tmp, [\rx, #UARTn_CMD]
+               .endm
+
+               .macro  senduart,rd,rx
+               strb    \rd, [\rx, #UARTn_TXDATA]
+               .endm
+
+               .macro  waituart,rd,rx
+1001:          ldr     \rd, [\rx, #UARTn_STATUS]
+               tst     \rd, #UARTn_STATUS_TXBL
+               beq     1001b
+               .endm
+
+               .macro  busyuart,rd,rx
+1001:          ldr     \rd, [\rx, UARTn_STATUS]
+               tst     \rd, #UARTn_STATUS_TXC
+               bne     1001b
+               .endm