diff options
Diffstat (limited to 'drivers/tty/hvc')
| -rw-r--r-- | drivers/tty/hvc/Kconfig | 30 | ||||
| -rw-r--r-- | drivers/tty/hvc/hvc_dcc.c | 28 |
2 files changed, 43 insertions, 15 deletions
diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig index 4d22b911111f..6a3c97d345a0 100644 --- a/drivers/tty/hvc/Kconfig +++ b/drivers/tty/hvc/Kconfig @@ -70,26 +70,26 @@ config HVC_XEN_FRONTEND Xen driver for secondary virtual consoles config HVC_UDBG - bool "udbg based fake hypervisor console" - depends on PPC - select HVC_DRIVER - help - This is meant to be used during HW bring up or debugging when - no other console mechanism exist but udbg, to get you a quick - console for userspace. Do NOT enable in production kernels. + bool "udbg based fake hypervisor console" + depends on PPC + select HVC_DRIVER + help + This is meant to be used during HW bring up or debugging when + no other console mechanism exist but udbg, to get you a quick + console for userspace. Do NOT enable in production kernels. config HVC_DCC - bool "ARM JTAG DCC console" - depends on ARM || ARM64 - select HVC_DRIVER - help - This console uses the JTAG DCC on ARM to create a console under the HVC - driver. This console is used through a JTAG only on ARM. If you don't have - a JTAG then you probably don't want this option. + bool "ARM JTAG DCC console" + depends on ARM || ARM64 + select HVC_DRIVER + help + This console uses the JTAG DCC on ARM to create a console under the HVC + driver. This console is used through a JTAG only on ARM. If you don't have + a JTAG then you probably don't want this option. config HVC_RISCV_SBI bool "RISC-V SBI console support" - depends on RISCV + depends on RISCV_SBI select HVC_DRIVER help This enables support for console output via RISC-V SBI calls, which diff --git a/drivers/tty/hvc/hvc_dcc.c b/drivers/tty/hvc/hvc_dcc.c index 02629a1f193d..8e0edb7d93fd 100644 --- a/drivers/tty/hvc/hvc_dcc.c +++ b/drivers/tty/hvc/hvc_dcc.c @@ -1,7 +1,10 @@ // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2010, 2014 The Linux Foundation. All rights reserved. */ +#include <linux/console.h> #include <linux/init.h> +#include <linux/serial.h> +#include <linux/serial_core.h> #include <asm/dcc.h> #include <asm/processor.h> @@ -12,6 +15,31 @@ #define DCC_STATUS_RX (1 << 30) #define DCC_STATUS_TX (1 << 29) +static void dcc_uart_console_putchar(struct uart_port *port, int ch) +{ + while (__dcc_getstatus() & DCC_STATUS_TX) + cpu_relax(); + + __dcc_putchar(ch); +} + +static void dcc_early_write(struct console *con, const char *s, unsigned n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, dcc_uart_console_putchar); +} + +static int __init dcc_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + device->con->write = dcc_early_write; + + return 0; +} + +EARLYCON_DECLARE(dcc, dcc_early_console_setup); + static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count) { int i; |