Merge tag 'tty-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here is the big tty and serial driver update for 4.4-rc1.

  Lots of serial driver updates and a few small tty core changes.  Full
  details in the shortlog.

  All of these have been in linux-next for a while"

* tag 'tty-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (148 commits)
  tty: Use unbound workqueue for all input workers
  tty: Abstract tty buffer work
  tty: Prevent tty teardown during tty_write_message()
  tty: core: Use correct spinlock flavor in tiocspgrp()
  tty: Combine SIGTTOU/SIGTTIN handling
  serial: amba-pl011: fix incorrect integer size in pl011_fifo_to_tty()
  ttyFDC: Fix build problems due to use of module_{init,exit}
  tty: remove unneeded return statement
  serial: 8250_mid: add support for DMA engine handling from UART MMIO
  dmaengine: hsu: remove platform data
  dmaengine: hsu: introduce stubs for the exported functions
  dmaengine: hsu: make the UART driver in control of selecting this driver
  serial: fix mctrl helper functions
  serial: 8250_pci: Intel MID UART support to its own driver
  serial: fsl_lpuart: add earlycon support
  tty: disable unbind for old 74xx based serial/mpsc console port
  serial: pl011: Spelling s/clocks-names/clock-names/
  n_tty: Remove reader wakeups for TTY_BREAK/TTY_PARITY chars
  tty: synclink, fix indentation
  serial: at91, fix rs485 properties
  ...

1 files changed, 55 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/dcc.h b/arch/arm64/include/asm/dcc.h
new file mode 100644
index 000000000000..65e0190e97c8
--- /dev/null
+++ b/arch/arm64/include/asm/dcc.h
@@ -0,0 +1,55 @@
+/* Copyright (c) 2014-2015 The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * A call to __dcc_getchar() or __dcc_putchar() is typically followed by
+ * a call to __dcc_getstatus().  We want to make sure that the CPU does
+ * not speculative read the DCC status before executing the read or write
+ * instruction.  That's what the ISBs are for.
+ *
+ * The 'volatile' ensures that the compiler does not cache the status bits,
+ * and instead reads the DCC register every time.
+ */
+#ifndef __ASM_DCC_H
+#define __ASM_DCC_H
+
+#include <asm/barrier.h>
+
+static inline u32 __dcc_getstatus(void)
+{
+	u32 ret;
+
+	asm volatile("mrs %0, mdccsr_el0" : "=r" (ret));
+
+	return ret;
+}
+
+static inline char __dcc_getchar(void)
+{
+	char c;
+
+	asm volatile("mrs %0, dbgdtrrx_el0" : "=r" (c));
+	isb();
+
+	return c;
+}
+
+static inline void __dcc_putchar(char c)
+{
+	/*
+	 * The typecast is to make absolutely certain that 'c' is
+	 * zero-extended.
+	 */
+	asm volatile("msr dbgdtrtx_el0, %0"
+			: : "r" ((unsigned long)(unsigned char)c));
+	isb();
+}
+
+#endif