hdat: Parse BMC nodes much earlier

This moves the parsing of the BMC and LPC details to the start of the
HDAT parsing. This allows us to enable the Skiboot log console earlier
so we can get debug output while parsing the rest of the HDAT.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/hw/lpc-uart.c b/hw/lpc-uart.c
index 9034fbd5..6e349ef9 100644
--- a/hw/lpc-uart.c
+++ b/hw/lpc-uart.c
@@ -548,6 +548,37 @@ static bool uart_init_hw(unsigned int speed, unsigned int clock)
 	return false;
 }
 
+/*
+ * early_uart_init() is similar to uart_init() in that it configures skiboot
+ * console log to output via a UART. The main differences are that the early
+ * version only works with MMIO UARTs and will not setup interrupts or locks.
+ */
+void early_uart_init(void)
+{
+	struct dt_node *uart_node;
+	u32 clk, baud;
+
+	uart_node = dt_find_compatible_node(dt_root, NULL, "ns16550");
+	if (!uart_node)
+		return;
+
+	/* Try translate the address, if this fails then it's not a MMIO UART */
+	mmio_uart_base = (void *) dt_translate_address(uart_node, 0, NULL);
+	if (!mmio_uart_base)
+		return;
+
+	clk = dt_prop_get_u32(uart_node, "clock-frequency");
+	baud = dt_prop_get_u32(uart_node, "current-speed");
+
+	if (uart_init_hw(baud, clk)) {
+		set_console(&uart_con_driver);
+		prlog(PR_NOTICE, "UART: Using UART at %p\n", mmio_uart_base);
+	} else {
+		prerror("UART: Early init failed!");
+		mmio_uart_base = NULL;
+	}
+}
+
 void uart_init(void)
 {
 	const struct dt_property *prop;
@@ -555,6 +586,9 @@ void uart_init(void)
 	char *path __unused;
 	const uint32_t *irqp;
 
+	/* Clean up after early_uart_init() */
+	mmio_uart_base = NULL;
+
 	/* UART lock is in the console path and thus must block
 	 * printf re-entrancy
 	 */