[kvm-unit-tests PATCH v3 3/5] lib: arm: Use ns16550a UART when --vmm=kvmtool

[Alexandru Elisei <alexandru.elisei@xxxxxxx>]

When kvm-unit-tests is configured with --vmm=kvmtool, use the address for
the ns16550a UART that kvmtool emulates. When the virtual machine manager
is QEMU, use the address for the pl011 UART, as before.

Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
---
 configure    |  9 +++++++--
 lib/arm/io.c | 27 ++++++++++++++++++---------
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/configure b/configure
index d1dd7d5830eb..30112a812d0b 100755
--- a/configure
+++ b/configure
@@ -114,7 +114,11 @@ if [ "$arch" = "i386" ] || [ "$arch" = "x86_64" ]; then
     testdir=x86
 elif [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then
     testdir=arm
-    if [ "$vmm" != "qemu" ] && [ "$vmm" != "kvmtool" ]; then
+    if [ "$vmm" = "qemu" ]; then
+        arm_uart_early_addr=0x09000000
+    elif [ "$vmm" = "kvmtool" ]; then
+        arm_uart_early_addr=0x3f8
+    else
         echo '--vmm must be one of "qemu" or "kvmtool"!'
         usage
     fi
@@ -216,11 +220,12 @@ cat <<EOF > lib/config.h
  * Generated file. DO NOT MODIFY.
  *
  */
+
 EOF
 if [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then
 cat <<EOF >> lib/config.h
 
-#define CONFIG_UART_EARLY_BASE 0x09000000
+#define CONFIG_UART_EARLY_BASE ${arm_uart_early_addr}
 
 EOF
 fi
diff --git a/lib/arm/io.c b/lib/arm/io.c
index e84a5c89fcb1..e55b8b854869 100644
--- a/lib/arm/io.c
+++ b/lib/arm/io.c
@@ -21,10 +21,10 @@ extern void halt(int code);
 
 static struct spinlock uart_lock;
 /*
- * Use this guess for the pl011 base in order to make an attempt at
+ * Use this guess for the uart base in order to make an attempt at
  * having earlier printf support. We'll overwrite it with the real
  * base address that we read from the device tree later. This is
- * the address we expect QEMU's mach-virt machine type to put in
+ * the address we expect the virtual machine manager to put in
  * its generated device tree.
  */
 #define UART_EARLY_BASE (u8 *)(unsigned long)CONFIG_UART_EARLY_BASE
@@ -32,22 +32,31 @@ static volatile u8 *uart0_base = UART_EARLY_BASE;
 
 static void uart0_init(void)
 {
-	const char *compatible = "arm,pl011";
+	/*
+	 * kvm-unit-tests uses the uart only for output. Both uart models have
+	 * the TX register at offset 0 from the base address, so there is no
+	 * need to treat them separately.
+	 */
+	const char *compatible[] = {"arm,pl011", "ns16550a"};
 	struct dt_pbus_reg base;
-	int ret;
+	int i, ret;
 
 	ret = dt_get_default_console_node();
 	assert(ret >= 0 || ret == -FDT_ERR_NOTFOUND);
 
 	if (ret == -FDT_ERR_NOTFOUND) {
 
-		ret = dt_pbus_get_base_compatible(compatible, &base);
-		assert(ret == 0 || ret == -FDT_ERR_NOTFOUND);
+		for (i = 0; i < ARRAY_SIZE(compatible); i++) {
+			ret = dt_pbus_get_base_compatible(compatible[i], &base);
+			assert(ret == 0 || ret == -FDT_ERR_NOTFOUND);
+
+			if (ret == 0)
+				break;
+		}
 
 		if (ret) {
-			printf("%s: %s not found in the device tree, "
-				"aborting...\n",
-				__func__, compatible);
+			printf("%s: Compatible uart not found in the device tree, "
+				"aborting...\n", __func__);
 			abort();
 		}
 
-- 
2.17.0