@@ -119,6 +119,17 @@ config DEBUG_UART_UARTLITE
You will need to provide parameters to make this work. The driver will
be available until the real driver-model serial is running.
+config DEBUG_UART_ARM_DCC
+ bool "ARM DCC"
+ help
+ Select this to enable a debug UART using the ARM JTAG DCC port.
+ The DCC port can be used for very early debugging and doesn't require
+ any additional setting like address/baudrate/clock. On systems without
+ any serial interface this is the easiest way how to get console.
+ Every ARM core has own DCC port which is the part of debug interface.
+ This port is available at least on ARMv6, ARMv7, ARMv8 and XScale
+ architectures.
+
config DEBUG_UART_ZYNQ
bool "Xilinx Zynq"
help
@@ -1,6 +1,7 @@
/*
* Copyright (C) 2004-2007 ARM Limited.
* Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ * Copyright (C) 2015 - 2016 Xilinx, Inc, Michal Simek
*
* SPDX-License-Identifier: GPL-2.0
*
@@ -16,6 +17,7 @@
*/
#include <common.h>
+#include <dm.h>
#include <serial.h>
#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V7)
@@ -94,12 +96,7 @@
#define TIMEOUT_COUNT 0x4000000
-static int arm_dcc_init(void)
-{
- return 0;
-}
-
-static int arm_dcc_getc(void)
+static int arm_dcc_getc(struct udevice *dev)
{
int ch;
register unsigned int reg;
@@ -112,7 +109,7 @@ static int arm_dcc_getc(void)
return ch;
}
-static void arm_dcc_putc(char ch)
+static int arm_dcc_putc(struct udevice *dev, char ch)
{
register unsigned int reg;
unsigned int timeout_count = TIMEOUT_COUNT;
@@ -123,41 +120,57 @@ static void arm_dcc_putc(char ch)
break;
}
if (timeout_count == 0)
- return;
+ return -EAGAIN;
else
write_dcc(ch);
+
+ return 0;
}
-static int arm_dcc_tstc(void)
+static int arm_dcc_pending(struct udevice *dev, bool input)
{
register unsigned int reg;
- can_read_dcc(reg);
+ if (input) {
+ can_read_dcc(reg);
+ } else {
+ can_write_dcc(reg);
+ }
return reg;
}
-static void arm_dcc_setbrg(void)
-{
-}
+static const struct dm_serial_ops arm_dcc_ops = {
+ .putc = arm_dcc_putc,
+ .pending = arm_dcc_pending,
+ .getc = arm_dcc_getc,
+};
+
+static const struct udevice_id arm_dcc_ids[] = {
+ { .compatible = "arm,dcc", },
+ { }
+};
-static struct serial_device arm_dcc_drv = {
+U_BOOT_DRIVER(serial_dcc) = {
.name = "arm_dcc",
- .start = arm_dcc_init,
- .stop = NULL,
- .setbrg = arm_dcc_setbrg,
- .putc = arm_dcc_putc,
- .puts = default_serial_puts,
- .getc = arm_dcc_getc,
- .tstc = arm_dcc_tstc,
+ .id = UCLASS_SERIAL,
+ .of_match = arm_dcc_ids,
+ .ops = &arm_dcc_ops,
+ .flags = DM_FLAG_PRE_RELOC,
};
-void arm_dcc_initialize(void)
+#ifdef CONFIG_DEBUG_UART_ARM_DCC
+
+#include <debug_uart.h>
+
+static inline void _debug_uart_init(void)
{
- serial_register(&arm_dcc_drv);
}
-__weak struct serial_device *default_serial_console(void)
+static inline void _debug_uart_putc(int ch)
{
- return &arm_dcc_drv;
+ arm_dcc_putc(NULL, ch);
}
+
+DEBUG_UART_FUNCS
+#endif
Enabling this driver requires some DT changes. Adding DCC to root or main bus: dcc: dcc { compatible = "arm,dcc"; u-boot,dm-pre-reloc; }; Extend alias list to link DCC: serial0 = &uart0; serial1 = &uart1; serial2 = &dcc; Change stdout-path to point to dcc port. stdout-path = "serial2:115200n8"; Also add support for debug uart to help with early debug. Signed-off-by: Michal Simek <michal.simek@xilinx.com> --- Changes in v2: - Extend Kconfig entry description drivers/serial/Kconfig | 11 +++++++++ drivers/serial/arm_dcc.c | 63 +++++++++++++++++++++++++++++------------------- 2 files changed, 49 insertions(+), 25 deletions(-)