drivers: imx_lpuart: add i.MX lpuart driver

add new lpuart driver
This driver is used by the i.MX 7ulp SoC

Signed-off-by: Peng Fan <peng.fan@nxp.com>

3 files changed, 93 insertions, 0 deletions

diff --git a/core/drivers/imx_lpuart.c b/core/drivers/imx_lpuart.c
new file mode 100644
index 00000000..8997bb49
--- /dev/null
+++ b/core/drivers/imx_lpuart.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright 2017-2018 NXP
+ *
+ */
+
+#include <assert.h>
+#include <drivers/imx_lpuart.h>
+#include <io.h>
+#include <keep.h>
+#include <util.h>
+
+#define STAT		0x14
+#define DATA		0x1C
+#define STAT_TDRE	BIT(23)
+#define STAT_RDRF	BIT(21)
+#define STAT_OR		BIT(19)
+
+static vaddr_t chip_to_base(struct serial_chip *chip)
+{
+	struct imx_lpuart_data *pd =
+		container_of(chip, struct imx_lpuart_data, chip);
+
+	return io_pa_or_va(&pd->base);
+}
+
+static void imx_lpuart_flush(struct serial_chip *chip __unused)
+{
+
+}
+
+static int imx_lpuart_getchar(struct serial_chip *chip)
+{
+	int ch;
+	vaddr_t base = chip_to_base(chip);
+
+	while (read32(base + STAT) & STAT_RDRF)
+		;
+
+	ch = (read32(base + DATA) & 0x3ff);
+
+	if (read32(base + STAT) & STAT_OR)
+		write32(base + STAT, STAT_OR);
+
+	return ch;
+}
+
+static void imx_lpuart_putc(struct serial_chip *chip, int ch)
+{
+	vaddr_t base = chip_to_base(chip);
+
+	while (!(read32(base + STAT) & STAT_TDRE))
+		__asm__ __volatile__("" : : : "memory");
+	write32(ch, base + DATA);
+}
+
+static const struct serial_ops imx_lpuart_ops = {
+	.flush = imx_lpuart_flush,
+	.getchar = imx_lpuart_getchar,
+	.putc = imx_lpuart_putc,
+};
+KEEP_PAGER(imx_lpuart_ops);
+
+void imx_lpuart_init(struct imx_lpuart_data *pd, paddr_t base)
+{
+	pd->base.pa = base;
+	pd->chip.ops = &imx_lpuart_ops;
+
+	/*
+	 * Do nothing, debug uart(sc lpuart) share with normal world,
+	 * everything for uart0 intialization is done in scfw.
+	 */
+}
diff --git a/core/drivers/sub.mk b/core/drivers/sub.mk
index ac058155..6ae44875 100644
--- a/core/drivers/sub.mk
+++ b/core/drivers/sub.mk
@@ -11,6 +11,7 @@ srcs-$(CFG_8250_UART) += serial8250_uart.c
 srcs-$(CFG_16550_UART) += ns16550.c
 srcs-$(CFG_IMX_SNVS) += imx_snvs.c
 srcs-$(CFG_IMX_UART) += imx_uart.c
+srcs-$(CFG_IMX_LPUART) += imx_lpuart.c
 srcs-$(CFG_IMX_WDOG) += imx_wdog.c
 cflags-imx_wdog.c-y += -Wno-suggest-attribute=noreturn
 srcs-$(CFG_SPRD_UART) += sprd_uart.c
diff --git a/core/include/drivers/imx_lpuart.h b/core/include/drivers/imx_lpuart.h
new file mode 100644
index 00000000..8048fcd9
--- /dev/null
+++ b/core/include/drivers/imx_lpuart.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright 2017-2018 NXP
+ *
+ */
+#ifndef IMX_LPUART_H
+#define IMX_LPUART_H
+
+#include <types_ext.h>
+#include <drivers/serial.h>
+
+struct imx_lpuart_data {
+	struct io_pa_va base;
+	struct serial_chip chip;
+};
+
+void imx_lpuart_init(struct imx_lpuart_data *pd, paddr_t base);
+
+#endif /* IMX_LPUART_H */