[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6
The attached patches provides part 6 of an architecture implementation for the
Tensilica Xtensa CPU series.
Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-xtensa/system.h b/include/asm-xtensa/system.h
new file mode 100644
index 0000000..690fe32
--- /dev/null
+++ b/include/asm-xtensa/system.h
@@ -0,0 +1,252 @@
+/*
+ * include/asm-xtensa/system.h
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001 - 2005 Tensilica Inc.
+ */
+
+#ifndef _XTENSA_SYSTEM_H
+#define _XTENSA_SYSTEM_H
+
+#include <linux/config.h>
+#include <linux/stringify.h>
+
+#include <asm/processor.h>
+
+/* interrupt control */
+
+#define local_save_flags(x) \
+ __asm__ __volatile__ ("rsr %0,"__stringify(PS) : "=a" (x));
+#define local_irq_restore(x) do { \
+ __asm__ __volatile__ ("wsr %0, "__stringify(PS)" ; rsync" \
+ :: "a" (x) : "memory"); } while(0);
+#define local_irq_save(x) do { \
+ __asm__ __volatile__ ("rsil %0, "__stringify(LOCKLEVEL) \
+ : "=a" (x) :: "memory");} while(0);
+
+static inline void local_irq_disable(void)
+{
+ unsigned long flags;
+ __asm__ __volatile__ ("rsil %0, "__stringify(LOCKLEVEL)
+ : "=a" (flags) :: "memory");
+}
+static inline void local_irq_enable(void)
+{
+ unsigned long flags;
+ __asm__ __volatile__ ("rsil %0, 0" : "=a" (flags) :: "memory");
+
+}
+
+static inline int irqs_disabled(void)
+{
+ unsigned long flags;
+ local_save_flags(flags);
+ return flags & 0xf;
+}
+
+#define RSR_CPENABLE(x) do { \
+ __asm__ __volatile__("rsr %0," __stringify(CPENABLE) : "=a" (x)); \
+ } while(0);
+#define WSR_CPENABLE(x) do { \
+ __asm__ __volatile__("wsr %0," __stringify(CPENABLE)";rsync" \
+ :: "a" (x));} while(0);
+
+#define clear_cpenable() __clear_cpenable()
+
+extern __inline__ void __clear_cpenable(void)
+{
+#if XCHAL_HAVE_CP
+ unsigned long i = 0;
+ WSR_CPENABLE(i);
+#endif
+}
+
+extern __inline__ void enable_coprocessor(int i)
+{
+#if XCHAL_HAVE_CP
+ int cp;
+ RSR_CPENABLE(cp);
+ cp |= 1 << i;
+ WSR_CPENABLE(cp);
+#endif
+}
+
+extern __inline__ void disable_coprocessor(int i)
+{
+#if XCHAL_HAVE_CP
+ int cp;
+ RSR_CPENABLE(cp);
+ cp &= ~(1 << i);
+ WSR_CPENABLE(cp);
+#endif
+}
+
+#define smp_read_barrier_depends() do { } while(0)
+#define read_barrier_depends() do { } while(0)
+
+#define mb() barrier()
+#define rmb() mb()
+#define wmb() mb()
+
+#ifdef CONFIG_SMP
+#error smp_* not defined
+#else
+#define smp_mb() barrier()
+#define smp_rmb() barrier()
+#define smp_wmb() barrier()
+#endif
+
+#define set_mb(var, value) do { var = value; mb(); } while (0)
+#define set_wmb(var, value) do { var = value; wmb(); } while (0)
+
+#if !defined (__ASSEMBLY__)
+
+/* * switch_to(n) should switch tasks to task nr n, first
+ * checking that n isn't the current task, in which case it does nothing.
+ */
+extern void *_switch_to(void *last, void *next);
+
+#endif /* __ASSEMBLY__ */
+
+#define prepare_to_switch() do { } while(0)
+
+#define switch_to(prev,next,last) \
+do { \
+ clear_cpenable(); \
+ (last) = _switch_to(prev, next); \
+} while(0)
+
+/*
+ * cmpxchg
+ */
+
+extern __inline__ unsigned long
+__cmpxchg_u32(volatile int *p, int old, int new)
+{
+ __asm__ __volatile__("rsil a15, "__stringify(LOCKLEVEL)"\n\t"
+ "l32i %0, %1, 0 \n\t"
+ "bne %0, %2, 1f \n\t"
+ "s32i %3, %1, 0 \n\t"
+ "1: \n\t"
+ "wsr a15, "__stringify(PS)" \n\t"
+ "rsync \n\t"
+ : "=&a" (old)
+ : "a" (p), "a" (old), "r" (new)
+ : "a15", "memory");
+ return old;
+}
+/* This function doesn't exist, so you'll get a linker error
+ * if something tries to do an invalid cmpxchg(). */
+
+extern void __cmpxchg_called_with_bad_pointer(void);
+
+static __inline__ unsigned long
+__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
+{
+ switch (size) {
+ case 4: return __cmpxchg_u32(ptr, old, new);
+ default: __cmpxchg_called_with_bad_pointer();
+ return old;
+ }
+}
+
+#define cmpxchg(ptr,o,n) \
+ ({ __typeof__(*(ptr)) _o_ = (o); \
+ __typeof__(*(ptr)) _n_ = (n); \
+ (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
+ (unsigned long)_n_, sizeof (*(ptr))); \
+ })
+
+
+
+
+/*
+ * xchg_u32
+ *
+ * Note that a15 is used here because the register allocation
+ * done by the compiler is not guaranteed and a window overflow
+ * may not occur between the rsil and wsr instructions. By using
+ * a15 in the rsil, the machine is guaranteed to be in a state
+ * where no register reference will cause an overflow.
+ */
+
+extern __inline__ unsigned long xchg_u32(volatile int * m, unsigned long val)
+{
+ unsigned long tmp;
+ __asm__ __volatile__("rsil a15, "__stringify(LOCKLEVEL)"\n\t"
+ "l32i %0, %1, 0 \n\t"
+ "s32i %2, %1, 0 \n\t"
+ "wsr a15, "__stringify(PS)" \n\t"
+ "rsync \n\t"
+ : "=&a" (tmp)
+ : "a" (m), "a" (val)
+ : "a15", "memory");
+ return tmp;
+}
+
+#define tas(ptr) (xchg((ptr),1))
+
+#if ( __XCC__ == 1 )
+
+/* xt-xcc processes __inline__ differently than xt-gcc and decides to
+ * insert an out-of-line copy of function __xchg. This presents the
+ * unresolved symbol at link time of __xchg_called_with_bad_pointer,
+ * even though such a function would never be called at run-time.
+ * xt-gcc always inlines __xchg, and optimizes away the undefined
+ * bad_pointer function.
+ */
+
+#define xchg(ptr,x) xchg_u32(ptr,x)
+
+#else /* assume xt-gcc */
+
+#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
+
+/*
+ * This only works if the compiler isn't horribly bad at optimizing.
+ * gcc-2.5.8 reportedly can't handle this, but I define that one to
+ * be dead anyway.
+ */
+
+extern void __xchg_called_with_bad_pointer(void);
+
+static __inline__ unsigned long
+__xchg(unsigned long x, volatile void * ptr, int size)
+{
+ switch (size) {
+ case 4:
+ return xchg_u32(ptr, x);
+ }
+ __xchg_called_with_bad_pointer();
+ return x;
+}
+
+#endif
+
+extern void set_except_vector(int n, void *addr);
+
+static inline void spill_registers(void)
+{
+ unsigned int a0, ps;
+
+ __asm__ __volatile__ (
+ "movi a14," __stringify (PS_EXCM_MASK) " | 1\n\t"
+ "mov a12, a0\n\t"
+ "rsr a13," __stringify(SAR) "\n\t"
+ "xsr a14," __stringify(PS) "\n\t"
+ "movi a0, _spill_registers\n\t"
+ "rsync\n\t"
+ "callx0 a0\n\t"
+ "mov a0, a12\n\t"
+ "wsr a13," __stringify(SAR) "\n\t"
+ "wsr a14," __stringify(PS) "\n\t"
+ :: "a" (&a0), "a" (&ps)
+ : "a2", "a3", "a12", "a13", "a14", "a15", "memory");
+}
+
+#define arch_align_stack(x) (x)
+
+#endif /* _XTENSA_SYSTEM_H */