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, 126 insertions, 0 deletions

diff --git a/arch/hexagon/include/asm/system.h b/arch/hexagon/include/asm/system.h
new file mode 100644
index 0000000..323ed1d
--- /dev/null
+++ b/arch/hexagon/include/asm/system.h
@@ -0,0 +1,126 @@
+/*
+ * System level definitions 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_SYSTEM_H
+#define _ASM_SYSTEM_H
+
+#include <linux/linkage.h>
+#include <linux/irqflags.h>
+#include <asm/atomic.h>
+#include <asm/hexagon_vm.h>
+
+struct thread_struct;
+
+extern struct task_struct *__switch_to(struct task_struct *,
+	struct task_struct *,
+	struct task_struct *);
+
+#define switch_to(p, n, r) do {\
+	r = __switch_to((p), (n), (r));\
+} while (0)
+
+
+#define rmb()				barrier()
+#define read_barrier_depends()		barrier()
+#define wmb()				barrier()
+#define mb()				barrier()
+#define smp_rmb()			barrier()
+#define smp_read_barrier_depends()	barrier()
+#define smp_wmb()			barrier()
+#define smp_mb()			barrier()
+#define smp_mb__before_atomic_dec()	barrier()
+#define smp_mb__after_atomic_dec()	barrier()
+#define smp_mb__before_atomic_inc()	barrier()
+#define smp_mb__after_atomic_inc()	barrier()
+
+/*
+ * __xchg - atomically exchange a register and a memory location
+ * @x: value to swap
+ * @ptr: pointer to memory
+ * @size:  size of the value
+ *
+ * Only 4 bytes supported currently.
+ *
+ * Note:  there was an errata for V2 about .new's and memw_locked.
+ *
+ */
+static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
+				   int size)
+{
+	unsigned long retval;
+
+	/*  Can't seem to use printk or panic here, so just stop  */
+	if (size != 4) do { asm volatile("brkpt;\n"); } while (1);
+
+	__asm__ __volatile__ (
+	"1:	%0 = memw_locked(%1);\n"    /*  load into retval */
+	"	memw_locked(%1,P0) = %2;\n" /*  store into memory */
+	"	if !P0 jump 1b;\n"
+	: "=&r" (retval)
+	: "r" (ptr), "r" (x)
+	: "memory", "p0"
+	);
+	return retval;
+}
+
+/*
+ * Atomically swap the contents of a register with memory.  Should be atomic
+ * between multiple CPU's and within interrupts on the same CPU.
+ */
+#define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), \
+	sizeof(*(ptr))))
+
+/*  Set a value and use a memory barrier.  Used by the scheduler somewhere.  */
+#define set_mb(var, value) \
+	do { var = value; mb(); } while (0)
+
+/*
+ *  see rt-mutex-design.txt; cmpxchg supposedly checks if *ptr == A and swaps.
+ *  looks just like atomic_cmpxchg on our arch currently with a bunch of
+ *  variable casting.
+ */
+#define __HAVE_ARCH_CMPXCHG 1
+
+#define cmpxchg(ptr, old, new)					\
+({								\
+	__typeof__(ptr) __ptr = (ptr);				\
+	__typeof__(*(ptr)) __old = (old);			\
+	__typeof__(*(ptr)) __new = (new);			\
+	__typeof__(*(ptr)) __oldval = 0;			\
+								\
+	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" (__ptr), "r" (__old), "r" (__new)		\
+		: "memory", "p0"				\
+	);							\
+	__oldval;						\
+})
+
+/*  Should probably shoot for an 8-byte aligned stack pointer  */
+#define STACK_MASK (~7)
+#define arch_align_stack(x) (x & STACK_MASK)
+
+#endif