ARM: vexpress: Config option for early printk console

Versatile Express platform can be used in different configurations,
the console UART used by early printk may be located at different
addresses in the address space.

This patch makes it possible to select the base address of a PL011
UART to be used as a console output in the kernel configuration.
The default behaviour is still the heuristic detecting memory map
on Cortex-A core tiles.

The zImage decompressor will use the same configuration values
or print out nothing if DEBUG_LL is not enabled.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>

2 files changed, 55 insertions, 0 deletions

diff --git a/arch/arm/mach-vexpress/include/mach/debug-macro.S b/arch/arm/mach-vexpress/include/mach/debug-macro.S
index fa8224794e0b..9f509f55d078 100644
--- a/arch/arm/mach-vexpress/include/mach/debug-macro.S
+++ b/arch/arm/mach-vexpress/include/mach/debug-macro.S
@@ -18,6 +18,8 @@
 
 #define DEBUG_LL_VIRT_BASE              0xf8000000
 
+#if defined(CONFIG_DEBUG_VEXPRESS_UART0_DETECT)
+
                 .macro  addruart,rp,rv,tmp
 
                 @ Make an educated guess regarding the memory map:
@@ -41,3 +43,42 @@
                 .endm
 
 #include <asm/hardware/debug-pl01x.S>
+
+#elif defined(CONFIG_DEBUG_VEXPRESS_UART0_CA9)
+
+                .macro  addruart,rp,rv,tmp
+                mov     \rp, #DEBUG_LL_UART_OFFSET
+                orr     \rv, \rp, #DEBUG_LL_VIRT_BASE
+                orr     \rp, \rp, #DEBUG_LL_PHYS_BASE
+                .endm
+
+#include <asm/hardware/debug-pl01x.S>
+
+#elif defined(CONFIG_DEBUG_VEXPRESS_UART0_RS1)
+
+                .macro  addruart,rp,rv,tmp
+                mov     \rp, #DEBUG_LL_UART_OFFSET_RS1
+                orr     \rv, \rp, #DEBUG_LL_VIRT_BASE
+                orr     \rp, \rp, #DEBUG_LL_PHYS_BASE_RS1
+                .endm
+
+#include <asm/hardware/debug-pl01x.S>
+
+#else /* CONFIG_DEBUG_LL_UART_NONE */
+
+                .macro  addruart, rp, rv, tmp
+                /* Safe dummy values */
+                mov     \rp, #0
+                mov     \rv, #DEBUG_LL_VIRT_BASE
+                .endm
+
+                .macro  senduart,rd,rx
+                .endm
+
+                .macro  waituart,rd,rx
+                .endm
+
+                .macro  busyuart,rd,rx
+                .endm
+
+#endif
diff --git a/arch/arm/mach-vexpress/include/mach/uncompress.h b/arch/arm/mach-vexpress/include/mach/uncompress.h
index 7dab5596b868..1e472eb0bbdc 100644
--- a/arch/arm/mach-vexpress/include/mach/uncompress.h
+++ b/arch/arm/mach-vexpress/include/mach/uncompress.h
@@ -27,6 +27,7 @@
 
 static unsigned long get_uart_base(void)
 {
+#if defined(CONFIG_DEBUG_VEXPRESS_UART0_DETECT)
         unsigned long mpcore_periph;
 
         /*
@@ -42,6 +43,13 @@ static unsigned long get_uart_base(void)
                 return UART_BASE;
         else
                 return UART_BASE_RS1;
+#elif defined(CONFIG_DEBUG_VEXPRESS_UART0_CA9)
+        return UART_BASE;
+#elif defined(CONFIG_DEBUG_VEXPRESS_UART0_RS1)
+        return UART_BASE_RS1;
+#else
+        return 0;
+#endif
 }
 
 /*
@@ -51,6 +59,9 @@ static inline void putc(int c)
 {
         unsigned long base = get_uart_base();
 
+        if (!base)
+                return;
+
         while (AMBA_UART_FR(base) & (1 << 5))
                 barrier();
 
@@ -61,6 +72,9 @@ static inline void flush(void)
 {
         unsigned long base = get_uart_base();
 
+        if (!base)
+                return;
+
         while (AMBA_UART_FR(base) & (1 << 3))
                 barrier();
 }