Merge Qualcom Hexagon architecture

This is the fifth version of the patchset (with one tiny whitespace fix)
to the Linux kernel to support the Qualcomm Hexagon architecture.

Between now and the next pull requests, Richard Kuo should have his key
signed, etc., and should be back on kernel.org.  In the meantime, this
got merged as a emailed patch-series.

* Hexagon: (36 commits)
  Add extra arch overrides to asm-generic/checksum.h
  Hexagon: Add self to MAINTAINERS
  Hexagon: Add basic stacktrace functionality for Hexagon architecture.
  Hexagon: Add configuration and makefiles for the Hexagon architecture.
  Hexagon: Comet platform support
  Hexagon: kgdb support files
  Hexagon: Add page-fault support.
  Hexagon: Add page table header files & etc.
  Hexagon: Add ioremap support
  Hexagon: Provide DMA implementation
  Hexagon: Implement basic TLB management routines for Hexagon.
  Hexagon: Implement basic cache-flush support
  Hexagon: Provide basic implementation and/or stubs for I/O routines.
  Hexagon: Add user access functions
  Hexagon: Add locking types and functions
  Hexagon: Add SMP support
  Hexagon: Provide basic debugging and system trap support.
  Hexagon: Add ptrace support
  Hexagon: Add time and timer functions
  Hexagon: Add interrupts
  ...

1 files changed, 164 insertions, 0 deletions

diff --git a/arch/hexagon/include/asm/atomic.h b/arch/hexagon/include/asm/atomic.h
new file mode 100644
index 0000000..e220f90
--- /dev/null
+++ b/arch/hexagon/include/asm/atomic.h
@@ -0,0 +1,164 @@
+/*
+ * Atomic operations for the Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _ASM_ATOMIC_H
+#define _ASM_ATOMIC_H
+
+#include <linux/types.h>
+
+#define ATOMIC_INIT(i)		{ (i) }
+#define atomic_set(v, i)	((v)->counter = (i))
+
+/**
+ * atomic_read - reads a word, atomically
+ * @v: pointer to atomic value
+ *
+ * Assumes all word reads on our architecture are atomic.
+ */
+#define atomic_read(v)		((v)->counter)
+
+/**
+ * atomic_xchg - atomic
+ * @v: pointer to memory to change
+ * @new: new value (technically passed in a register -- see xchg)
+ */
+#define atomic_xchg(v, new)	(xchg(&((v)->counter), (new)))
+
+
+/**
+ * atomic_cmpxchg - atomic compare-and-exchange values
+ * @v: pointer to value to change
+ * @old:  desired old value to match
+ * @new:  new value to put in
+ *
+ * Parameters are then pointer, value-in-register, value-in-register,
+ * and the output is the old value.
+ *
+ * Apparently this is complicated for archs that don't support
+ * the memw_locked like we do (or it's broken or whatever).
+ *
+ * Kind of the lynchpin of the rest of the generically defined routines.
+ * Remember V2 had that bug with dotnew predicate set by memw_locked.
+ *
+ * "old" is "expected" old val, __oldval is actual old value
+ */
+static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
+{
+	int __oldval;
+
+	asm volatile(
+		"1:	%0 = memw_locked(%1);\n"
+		"	{ P0 = cmp.eq(%0,%2);\n"
+		"	  if (!P0.new) jump:nt 2f; }\n"
+		"	memw_locked(%1,P0) = %3;\n"
+		"	if (!P0) jump 1b;\n"
+		"2:\n"
+		: "=&r" (__oldval)
+		: "r" (&v->counter), "r" (old), "r" (new)
+		: "memory", "p0"
+	);
+
+	return __oldval;
+}
+
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+	int output;
+
+	__asm__ __volatile__ (
+		"1:	%0 = memw_locked(%1);\n"
+		"	%0 = add(%0,%2);\n"
+		"	memw_locked(%1,P3)=%0;\n"
+		"	if !P3 jump 1b;\n"
+		: "=&r" (output)
+		: "r" (&v->counter), "r" (i)
+		: "memory", "p3"
+	);
+	return output;
+
+}
+
+#define atomic_add(i, v) atomic_add_return(i, (v))
+
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+	int output;
+	__asm__ __volatile__ (
+		"1:	%0 = memw_locked(%1);\n"
+		"	%0 = sub(%0,%2);\n"
+		"	memw_locked(%1,P3)=%0\n"
+		"	if !P3 jump 1b;\n"
+		: "=&r" (output)
+		: "r" (&v->counter), "r" (i)
+		: "memory", "p3"
+	);
+	return output;
+}
+
+#define atomic_sub(i, v) atomic_sub_return(i, (v))
+
+/**
+ * atomic_add_unless - add unless the number is a given value
+ * @v: pointer to value
+ * @a: amount to add
+ * @u: unless value is equal to u
+ *
+ * Returns 1 if the add happened, 0 if it didn't.
+ */
+static inline int __atomic_add_unless(atomic_t *v, int a, int u)
+{
+	int output, __oldval;
+	asm volatile(
+		"1:	%0 = memw_locked(%2);"
+		"	{"
+		"		p3 = cmp.eq(%0, %4);"
+		"		if (p3.new) jump:nt 2f;"
+		"		%0 = add(%0, %3);"
+		"		%1 = #0;"
+		"	}"
+		"	memw_locked(%2, p3) = %0;"
+		"	{"
+		"		if !p3 jump 1b;"
+		"		%1 = #1;"
+		"	}"
+		"2:"
+		: "=&r" (__oldval), "=&r" (output)
+		: "r" (v), "r" (a), "r" (u)
+		: "memory", "p3"
+	);
+	return output;
+}
+
+#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+
+#define atomic_inc(v) atomic_add(1, (v))
+#define atomic_dec(v) atomic_sub(1, (v))
+
+#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
+#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
+#define atomic_sub_and_test(i, v) (atomic_sub_return(i, (v)) == 0)
+#define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0)
+
+
+#define atomic_inc_return(v) (atomic_add_return(1, v))
+#define atomic_dec_return(v) (atomic_sub_return(1, v))
+
+#endif