Merge tag 'tty-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial updates from Greg KH:
 "Here is the "big" tty and serial driver patches for 5.5-rc1.

  It's a bit later in the merge window than normal as I wanted to make
  sure some last-minute patches applied to it were all sane. They seem
  to be :)

  There's a lot of little stuff in here, for the tty core, and for lots
  of serial drivers:

   - reverts of uartlite serial driver patches that were wrong

   - msm-serial driver fixes

   - serial core updates and fixes

   - tty core fixes

   - serial driver dma mapping api changes

   - lots of other tiny fixes and updates for serial drivers

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (58 commits)
  Revert "serial/8250: Add support for NI-Serial PXI/PXIe+485 devices"
  vcs: prevent write access to vcsu devices
  tty: vt: keyboard: reject invalid keycodes
  tty: don't crash in tty_init_dev when missing tty_port
  serial: stm32: fix clearing interrupt error flags
  tty: Fix Kconfig indentation, continued
  serial: serial_core: Perform NULL checks for break_ctl ops
  tty: remove unused argument from tty_open_by_driver()
  tty: Fix Kconfig indentation
  {tty: serial, nand: onenand}: samsung: rename to fix build warning
  serial: ifx6x60: add missed pm_runtime_disable
  serial: pl011: Fix DMA ->flush_buffer()
  Revert "serial-uartlite: Move the uart register"
  Revert "serial-uartlite: Add get serial id if not provided"
  Revert "serial-uartlite: Do not use static struct uart_driver out of probe()"
  Revert "serial-uartlite: Add runtime support"
  Revert "serial-uartlite: Change logic how console_port is setup"
  Revert "serial-uartlite: Use allocated structure instead of static ones"
  tty: serial: msm_serial: Use dma_request_chan() directly for channel request
  tty: serial: tegra: Use dma_request_chan() directly for channel request
  ...

2 files changed, 42 insertions, 14 deletions

diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig
index 4487a6b9acc8..6a3c97d345a0 100644
--- a/drivers/tty/hvc/Kconfig
+++ b/drivers/tty/hvc/Kconfig
@@ -70,22 +70,22 @@ 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"
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;