From 62486b40f309a18209a862130c787caedfe3c5cb Mon Sep 17 00:00:00 2001
From: Jan Kiszka <jan.kiszka@siemens.com>
Date: Tue, 26 Jan 2016 09:27:40 +0100
Subject: [PATCH] x86: Make debug UART port configurable via system config

We already allow to enable a VGA console via the system config, so let's
make the UART port configurable this way as well: phys_start will hold
the port, and flags must not have JAILHOUSE_MEM_IO set, in order to
differentiate us from the memory-mapped VGA console. And by leaving
phys_start at 0, we can even turn off the console now.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 hypervisor/arch/x86/dbg-write.c | 49 +++++++++++++++++----------------
 1 file changed, 26 insertions(+), 23 deletions(-)

diff --git a/hypervisor/arch/x86/dbg-write.c b/hypervisor/arch/x86/dbg-write.c
index cdb6b85..df6f459 100644
--- a/hypervisor/arch/x86/dbg-write.c
+++ b/hypervisor/arch/x86/dbg-write.c
@@ -12,35 +12,39 @@
  * the COPYING file in the top-level directory.
  */
 
+#include <jailhouse/control.h>
 #include <jailhouse/entry.h>
 #include <jailhouse/printk.h>
 #include <jailhouse/processor.h>
 #include <asm/io.h>
 
-#ifdef CONFIG_UART_OXPCIE952
-#define UART_BASE		0xe010
-#else
-#define UART_BASE		0x3f8
-#endif
-#define  UART_TX		0x0
-#define  UART_DLL		0x0
-#define  UART_DLM		0x1
-#define  UART_LCR		0x3
-#define  UART_LCR_8N1		0x03
-#define  UART_LCR_DLAB		0x80
-#define  UART_LSR		0x5
-#define  UART_LSR_THRE		0x20
+#define UART_TX			0x0
+#define UART_DLL		0x0
+#define UART_DLM		0x1
+#define UART_LCR		0x3
+#define UART_LCR_8N1		0x03
+#define UART_LCR_DLAB		0x80
+#define UART_LSR		0x5
+#define UART_LSR_THRE		0x20
+
+static u16 uart_base;
 
 static void uart_init(void)
 {
-	outb(UART_LCR_DLAB, UART_BASE + UART_LCR);
+	if (system_config->debug_console.phys_start == 0 ||
+	    system_config->debug_console.flags & JAILHOUSE_MEM_IO)
+		return;
+
+	uart_base = system_config->debug_console.phys_start;
+
+	outb(UART_LCR_DLAB, uart_base + UART_LCR);
 #ifdef CONFIG_UART_OXPCIE952
-	outb(0x22, UART_BASE + UART_DLL);
+	outb(0x22, uart_base + UART_DLL);
 #else
-	outb(1, UART_BASE + UART_DLL);
+	outb(1, uart_base + UART_DLL);
 #endif
-	outb(0, UART_BASE + UART_DLM);
-	outb(UART_LCR_8N1, UART_BASE + UART_LCR);
+	outb(0, uart_base + UART_DLM);
+	outb(UART_LCR_8N1, uart_base + UART_LCR);
 }
 
 static void uart_write(const char *msg)
@@ -54,11 +58,11 @@ static void uart_write(const char *msg)
 			c = *msg++;
 		if (!c)
 			break;
-		while (!(inb(UART_BASE + UART_LSR) & UART_LSR_THRE))
+		while (!(inb(uart_base + UART_LSR) & UART_LSR_THRE))
 			cpu_relax();
 		if (panic_in_progress && panic_cpu != phys_processor_id())
 			break;
-		outb(c, UART_BASE + UART_TX);
+		outb(c, uart_base + UART_TX);
 	}
 }
 
@@ -134,14 +138,13 @@ static void vga_write(const char *msg)
 void arch_dbg_write_init(void)
 {
 	vga_init();
-	if (!vga_mem)
-		uart_init();
+	uart_init();
 }
 
 void arch_dbg_write(const char *msg)
 {
 	if (vga_mem)
 		vga_write(msg);
-	else
+	else if (uart_base)
 		uart_write(msg);
 }
-- 
2.39.2