Arguably all of uart0_init() is unnecessary, as we're pretty sure
that the address we initialize uart0_base to is correct. We go
through the motions of finding the uart anyway though, because it's
easy. It's also easy to check chosen/stdout-path first, so let's do
that too. But, just to make all this stuff a little less unnecessary,
let's add a warning when we do actually find an address that doesn't
match our initializer.
Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx>
---
lib/arm/io.c | 36 +++++++++++++++++++++++++++---------
1 file changed, 27 insertions(+), 9 deletions(-)
diff --git a/lib/arm/io.c b/lib/arm/io.c
index 8b1501886736a..a08d394e4aa1c 100644
--- a/lib/arm/io.c
+++ b/lib/arm/io.c
@@ -19,12 +19,14 @@ extern void halt(int code);
/*
* Use this guess for the pl011 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.
+ * 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
+ * its generated device tree.
*/
-#define QEMU_MACH_VIRT_PL011_BASE 0x09000000UL
+#define UART_EARLY_BASE 0x09000000UL
static struct spinlock uart_lock;
-static volatile u8 *uart0_base = (u8 *)QEMU_MACH_VIRT_PL011_BASE;
+static volatile u8 *uart0_base = (u8 *)UART_EARLY_BASE;
static void uart0_init(void)
{
@@ -32,16 +34,32 @@ static void uart0_init(void)
struct dt_pbus_reg base;
int ret;
- ret = dt_pbus_get_base_compatible(compatible, &base);
- assert(ret == 0 || ret == -FDT_ERR_NOTFOUND);
+ ret = dt_get_default_console_node();
+ assert(ret >= 0 || ret == -FDT_ERR_NOTFOUND);
- if (ret) {
- printf("%s: %s not found in the device tree, aborting...\n",
- __func__, compatible);
- abort();
+ if (ret == -FDT_ERR_NOTFOUND) {
+
+ ret = dt_pbus_get_base_compatible(compatible, &base);
+ assert(ret == 0 || ret == -FDT_ERR_NOTFOUND);
+
+ if (ret) {
+ printf("%s: %s not found in the device tree, "
+ "aborting...\n",
+ __func__, compatible);
+ abort();
+ }
+
+ } else {
+ assert(dt_pbus_translate_node(ret, 0, &base) == 0);
}
uart0_base = ioremap(base.addr, base.size);
+
+ if (uart0_base != (u8 *)UART_EARLY_BASE) {
+ printf("WARNING: early print support may not work. "
+ "Found uart at %p, but early base is %p.\n",
+ uart0_base, (u8 *)UART_EARLY_BASE);
+ }
}
void io_init(void)
--
2.4.3
--
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