[PATCH] lib: utils: Add Xilinx uartlite implementation

[Guokai Chen]

Uartlite is a device commonly used on Xilinx platforms. We add OpenSBI support for uartlite so that OpenSBI boots on SoCs that utilize uartlite for output.

Signed-off-by: Guokai Chen <chenguokai17 at mails.ucas.ac.cn>
---
 include/sbi_utils/serial/xilinx-uart.h | 20 ++++++++++++
 lib/utils/serial/fdt_serial.c          |  2 ++
 lib/utils/serial/fdt_serial_xilinx.c   | 36 ++++++++++++++++++++++
 lib/utils/serial/objects.mk            |  2 ++
 lib/utils/serial/xilinx-uart.c         | 42 ++++++++++++++++++++++++++
 5 files changed, 102 insertions(+)
 create mode 100644 include/sbi_utils/serial/xilinx-uart.h
 create mode 100644 lib/utils/serial/fdt_serial_xilinx.c
 create mode 100644 lib/utils/serial/xilinx-uart.c

diff --git a/include/sbi_utils/serial/xilinx-uart.h b/include/sbi_utils/serial/xilinx-uart.h
new file mode 100644
index 0000000..e3d667e
--- /dev/null
+++ b/include/sbi_utils/serial/xilinx-uart.h
@@ -0,0 +1,20 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Guokai Chen <chenguokai17 at mails.ucas.ac.cn>
+ *
+ * This code is based on include/sbi_utils/serial/shakti-uart.h
+ */
+
+#ifndef __SERIAL_XILINX_UART_H__
+#define __SERIAL_XILINX_UART_H__
+
+#include <sbi/sbi_types.h>
+
+void xilinx_uart_putc(char ch);
+
+int xilinx_uart_getc(void);
+
+int xilinx_uart_init(unsigned long base, u32 in_freq, u32 baudrate);
+
+#endif
diff --git a/lib/utils/serial/fdt_serial.c b/lib/utils/serial/fdt_serial.c
index b9ce67e..8671ee3 100644
--- a/lib/utils/serial/fdt_serial.c
+++ b/lib/utils/serial/fdt_serial.c
@@ -16,12 +16,14 @@ extern struct fdt_serial fdt_serial_uart8250;
 extern struct fdt_serial fdt_serial_sifive;
 extern struct fdt_serial fdt_serial_htif;
 extern struct fdt_serial fdt_serial_shakti;
+extern struct fdt_serial fdt_serial_xilinx;
 
 static struct fdt_serial *serial_drivers[] = {
 	&fdt_serial_uart8250,
 	&fdt_serial_sifive,
 	&fdt_serial_htif,
 	&fdt_serial_shakti,
+	&fdt_serial_xilinx,
 };
 
 static void dummy_putc(char ch)
diff --git a/lib/utils/serial/fdt_serial_xilinx.c b/lib/utils/serial/fdt_serial_xilinx.c
new file mode 100644
index 0000000..8b52a7d
--- /dev/null
+++ b/lib/utils/serial/fdt_serial_xilinx.c
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Guokai Chen <chenguokai17 at mails.ucas.ac.cn>
+ * 
+ * This code is based on lib/utils/serial/fdt_serial_shakti.c
+ */
+
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/serial/fdt_serial.h>
+#include <sbi_utils/serial/xilinx-uart.h>
+
+static int serial_xilinx_init(void *fdt, int nodeoff,
+				const struct fdt_match *match)
+{
+		
+	int rc;
+	struct platform_uart_data uart;
+	// no need to reinvent a wheel
+	rc = fdt_parse_shakti_uart_node(fdt, nodeoff, &uart);
+	if (rc)
+		return rc;
+	return xilinx_uart_init(uart.addr, uart.freq, uart.baud);
+}
+
+static const struct fdt_match serial_xilinx_match[] = {
+	{ .compatible = "xilinx,uartlite" },
+	{ },
+};
+
+struct fdt_serial fdt_serial_xilinx = {
+	.match_table = serial_xilinx_match,
+	.init = serial_xilinx_init,
+	.getc = xilinx_uart_getc,
+	.putc = xilinx_uart_putc
+};
diff --git a/lib/utils/serial/objects.mk b/lib/utils/serial/objects.mk
index c0746f0..6089944 100644
--- a/lib/utils/serial/objects.mk
+++ b/lib/utils/serial/objects.mk
@@ -10,8 +10,10 @@
 libsbiutils-objs-y += serial/fdt_serial.o
 libsbiutils-objs-y += serial/fdt_serial_htif.o
 libsbiutils-objs-y += serial/fdt_serial_shakti.o
+libsbiutils-objs-y += serial/fdt_serial_xilinx.o
 libsbiutils-objs-y += serial/fdt_serial_sifive.o
 libsbiutils-objs-y += serial/fdt_serial_uart8250.o
 libsbiutils-objs-y += serial/shakti-uart.o
+libsbiutils-objs-y += serial/xilinx-uart.o
 libsbiutils-objs-y += serial/sifive-uart.o
 libsbiutils-objs-y += serial/uart8250.o
diff --git a/lib/utils/serial/xilinx-uart.c b/lib/utils/serial/xilinx-uart.c
new file mode 100644
index 0000000..ea32d47
--- /dev/null
+++ b/lib/utils/serial/xilinx-uart.c
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Guokai Chen <chenguokai17 at mails.ucas.ac.cn>
+ *
+ * This code is based on lib/utils/serial/xilinx-uart.c
+ */
+
+#include <sbi/riscv_io.h>
+#include <sbi/sbi_console.h>
+#include <sbi_utils/serial/xilinx-uart.h>
+
+#define REG_TX		0x04
+#define REG_RX		0x00
+#define REG_STATUS	0x08
+#define REG_CONTROL	0x0C
+
+#define UART_TX_FULL    (1<<0x3)
+#define UART_RX_VALID   (1<<0x0)
+
+static volatile void *uart_base;
+
+void xilinx_uart_putc(char ch)
+{
+	while((readb(uart_base + REG_STATUS) & UART_TX_FULL))
+		;
+	writeb(ch, uart_base + REG_TX);
+}
+
+int xilinx_uart_getc(void)
+{
+	u16 status = readb(uart_base + REG_STATUS);
+	if (status & UART_RX_VALID)
+		return readb(uart_base + REG_RX);
+	return -1;
+}
+
+int xilinx_uart_init(unsigned long base, u32 in_freq, u32 baudrate)
+{
+	uart_base = (volatile void *)base;
+	return 0;
+}
-- 
2.31.1