From: "chunyan.zhang" <chunyan.zhang@xxxxxxxxxxxxxx>
Adds earlycon support for the Spreadtrum's serial.
Signed-off-by: chunyan.zhang <chunyan.zhang@xxxxxxxxxxxxxx>
---
drivers/tty/serial/Kconfig | 12 ++++++
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/serial_sprd_early.c | 64 ++++++++++++++++++++++++++++++++
3 files changed, 77 insertions(+)
create mode 100644 drivers/tty/serial/serial_sprd_early.c
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 26cec64..ede16e6 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -85,6 +85,18 @@ config SERIAL_EARLYCON_ARM_SEMIHOST
with "earlycon=smh" on the kernel command line. The console is
enabled when early_param is processed.
+config SERIAL_EARLYCON_SPRD
+ bool "Early console using SPRD serial"
+ depends on ARM64
+ select SERIAL_CORE
+ select SERIAL_CORE_CONSOLE
+ select SERIAL_EARLYCON
+ help
+ Support for early debug console using SPRD serial. This enables
+ the console before standard serial driver is probed. This is enabled
+ with "earlycon=serial_sprd" on the kernel command line. The console is
+ enabled when early_param is processed.
+
config SERIAL_SB1250_DUART
tristate "BCM1xxx on-chip DUART serial support"
depends on SIBYTE_SB1xxx_SOC=y
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 0080cc3..3ea9edc 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_SERIAL_21285) += 21285.o
obj-$(CONFIG_SERIAL_EARLYCON) += earlycon.o
obj-$(CONFIG_SERIAL_EARLYCON_ARM_SEMIHOST) += earlycon-arm-semihost.o
+obj-$(CONFIG_SERIAL_EARLYCON_SPRD) += serial_sprd_early.o
# These Sparc drivers have to appear before others such as 8250
# which share ttySx minor node space. Otherwise console device
diff --git a/drivers/tty/serial/serial_sprd_early.c b/drivers/tty/serial/serial_sprd_early.c
new file mode 100644
index 0000000..059e109
--- /dev/null
+++ b/drivers/tty/serial/serial_sprd_early.c
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2012 Spreadtrum Communications Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/serial_core.h>
+#include <linux/of.h>
+
+/*offset*/
+#define ARM_UART_TXD 0x0000
+#define ARM_UART_RXD 0x0004
+#define ARM_UART_STS0 0x0008
+#define ARM_UART_STS1 0x000C
+#define ARM_UART_IEN 0x0010
+#define ARM_UART_ICLR 0x0014
+#define ARM_UART_CTL0 0x0018
+#define ARM_UART_CTL1 0x001C
+#define ARM_UART_CTL2 0x0020
+#define ARM_UART_CLKD0 0x0024
+#define ARM_UART_CLKD1 0x0028
+#define ARM_UART_STS2 0x002C
+
+/*line status */
+#define UART_LSR_TX_OVER (0x1<<15)
+
+static void serial_sprd_putc(struct uart_port *port, int c)
+{
+ while (!(readl(port->membase + ARM_UART_STS0) & UART_LSR_TX_OVER))
+ ;
+ writeb(c, port->membase + ARM_UART_TXD);
+}
+
+static void serial_sprd_early_write(struct console *con, const char *s,
+ unsigned n)
+{
+ struct earlycon_device *dev = con->data;
+
+ uart_console_write(&dev->port, s, n, serial_sprd_putc);
+}
+
+static int __init serial_sprd_early_console_setup(
+ struct earlycon_device *device,
+ const char *opt)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ device->con->write = serial_sprd_early_write;
+ return 0;
+}
+EARLYCON_DECLARE(serial_sprd, serial_sprd_early_console_setup);
+OF_EARLYCON_DECLARE(serial_sprd, "sprd,serial",
+ serial_sprd_early_console_setup);
--
1.7.9.5
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