1 files changed, 75 insertions, 0 deletions
diff --git a/core/drivers/amlogic_uart.c b/core/drivers/amlogic_uart.c
new file mode 100644
index 00000000..c5366090
--- /dev/null
+++ b/core/drivers/amlogic_uart.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright (c) 2020 Carlo Caione <ccaione@baylibre.com>
+ */
+
+#include <assert.h>
+#include <drivers/amlogic_uart.h>
+#include <io.h>
+#include <keep.h>
+#include <util.h>
+
+/* Registers */
+#define AML_UART_WFIFO		0x0000
+#define AML_UART_RFIFO		0x0004
+#define AML_UART_CONTROL	0x0008
+#define AML_UART_STATUS		0x000C
+#define AML_UART_MISC		0x0010
+
+/* AML_UART_STATUS bits */
+#define AML_UART_RX_EMPTY	BIT(20)
+#define AML_UART_TX_FULL	BIT(21)
+#define AML_UART_TX_EMPTY	BIT(22)
+
+static vaddr_t chip_to_base(struct serial_chip *chip)
+{
+	struct amlogic_uart_data *pd =
+		container_of(chip, struct amlogic_uart_data, chip);
+
+	return io_pa_or_va(&pd->base);
+}
+
+static void amlogic_uart_flush(struct serial_chip *chip)
+{
+	vaddr_t base = chip_to_base(chip);
+
+	while (!(io_read32(base + AML_UART_STATUS) & AML_UART_TX_EMPTY))
+		;
+}
+
+static int amlogic_uart_getchar(struct serial_chip *chip)
+{
+	vaddr_t base = chip_to_base(chip);
+
+	if (io_read32(base + AML_UART_STATUS) & AML_UART_RX_EMPTY)
+		return -1;
+
+	return io_read32(base + AML_UART_RFIFO) & 0xff;
+}
+
+static void amlogic_uart_putc(struct serial_chip *chip, int ch)
+{
+	vaddr_t base = chip_to_base(chip);
+
+	while (io_read32(base + AML_UART_STATUS) & AML_UART_TX_FULL)
+		;
+
+	io_write32(base + AML_UART_WFIFO, ch);
+}
+
+static const struct serial_ops amlogic_uart_ops = {
+	.flush = amlogic_uart_flush,
+	.getchar = amlogic_uart_getchar,
+	.putc = amlogic_uart_putc,
+};
+
+void amlogic_uart_init(struct amlogic_uart_data *pd, paddr_t base)
+{
+	pd->base.pa = base;
+	pd->chip.ops = &amlogic_uart_ops;
+
+	/*
+	 * Do nothing, debug uart (AO) shared with normal world, everything for
+	 * uart initialization is done in bootloader.
+	 */
+}