1 files changed, 82 insertions, 0 deletions
diff --git a/arch/x86/cpu/braswell/early_uart.c b/arch/x86/cpu/braswell/early_uart.c
new file mode 100644
index 0000000000..c70a8854fd
--- /dev/null
+++ b/arch/x86/cpu/braswell/early_uart.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2017, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+
+#define PCI_DEV_CONFIG(segbus, dev, fn) ( \
+		(((segbus) & 0xfff) << 20) | \
+		(((dev) & 0x1f) << 15) | \
+		(((fn)  & 0x07) << 12))
+
+/* Platform Controller Unit */
+#define LPC_DEV			0x1f
+#define LPC_FUNC		0
+
+/* Enable UART */
+#define UART_CONT		0x80
+
+/* UART PAD definitions */
+#define UART_RXD_COMMUITY	1
+#define UART_TXD_COMMUITY	1
+#define UART_RXD_FAMILY		4
+#define UART_TXD_FAMILY		4
+#define UART_RXD_PAD		2
+#define UART_TXD_PAD		7
+#define UART_RXD_FUNC		3
+#define UART_TXD_FUNC		3
+
+/* IO Memory */
+#define IO_BASE_ADDRESS		0xfed80000
+
+static inline uint32_t gpio_pconf0(int community, int family, int pad)
+{
+	return IO_BASE_ADDRESS + community * 0x8000 + 0x4400 +
+		family * 0x400 + pad * 8;
+}
+
+static void gpio_select_func(int community, int family, int pad, int func)
+{
+	uint32_t pconf0_addr = gpio_pconf0(community, family, pad);
+
+	clrsetbits_le32(pconf0_addr, 0xf << 16, func << 16);
+}
+
+static void x86_pci_write_config32(int dev, unsigned int where, u32 value)
+{
+	unsigned long addr;
+
+	addr = CONFIG_PCIE_ECAM_BASE | dev | (where & ~3);
+	writel(value, addr);
+}
+
+/* This can be called after memory-mapped PCI is working */
+int setup_internal_uart(int enable)
+{
+	/* Enable or disable the legacy UART hardware */
+	x86_pci_write_config32(PCI_DEV_CONFIG(0, LPC_DEV, LPC_FUNC), UART_CONT,
+			       enable);
+
+	/* All done for the disable part, so just return */
+	if (!enable)
+		return 0;
+
+	/*
+	 * Set up the pads to the UART function. This allows the signals to
+	 * leave the chip
+	 */
+	gpio_select_func(UART_RXD_COMMUITY, UART_RXD_FAMILY,
+			 UART_RXD_PAD, UART_RXD_FUNC);
+	gpio_select_func(UART_TXD_COMMUITY, UART_TXD_FAMILY,
+			 UART_TXD_PAD, UART_TXD_FUNC);
+
+	return 0;
+}
+
+void board_debug_uart_init(void)
+{
+	setup_internal_uart(1);
+}