arch/tile: core support for Tilera 32-bit chips.

This change is the core kernel support for TILEPro and TILE64 chips.
No driver support (except the console driver) is included yet.

This includes the relevant Linux headers in asm/; the low-level
low-level "Tile architecture" headers in arch/, which are
shared with the hypervisor, etc., and are build-system agnostic;
and the relevant hypervisor headers in hv/.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reviewed-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 220 insertions, 0 deletions

diff --git a/arch/tile/include/asm/system.h b/arch/tile/include/asm/system.h
new file mode 100644
index 00000000000..d6ca7f816c8
--- /dev/null
+++ b/arch/tile/include/asm/system.h
@@ -0,0 +1,220 @@
+/*
+ * Copyright 2010 Tilera Corporation. 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
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+#ifndef _ASM_TILE_SYSTEM_H
+#define _ASM_TILE_SYSTEM_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <linux/irqflags.h>
+
+/* NOTE: we can't include <linux/ptrace.h> due to #include dependencies. */
+#include <asm/ptrace.h>
+
+#include <arch/chip.h>
+#include <arch/sim_def.h>
+#include <arch/spr_def.h>
+
+/*
+ * read_barrier_depends - Flush all pending reads that subsequents reads
+ * depend on.
+ *
+ * No data-dependent reads from memory-like regions are ever reordered
+ * over this barrier.  All reads preceding this primitive are guaranteed
+ * to access memory (but not necessarily other CPUs' caches) before any
+ * reads following this primitive that depend on the data return by
+ * any of the preceding reads.  This primitive is much lighter weight than
+ * rmb() on most CPUs, and is never heavier weight than is
+ * rmb().
+ *
+ * These ordering constraints are respected by both the local CPU
+ * and the compiler.
+ *
+ * Ordering is not guaranteed by anything other than these primitives,
+ * not even by data dependencies.  See the documentation for
+ * memory_barrier() for examples and URLs to more information.
+ *
+ * For example, the following code would force ordering (the initial
+ * value of "a" is zero, "b" is one, and "p" is "&a"):
+ *
+ * <programlisting>
+ *      CPU 0                           CPU 1
+ *
+ *      b = 2;
+ *      memory_barrier();
+ *      p = &b;                         q = p;
+ *                                      read_barrier_depends();
+ *                                      d = *q;
+ * </programlisting>
+ *
+ * because the read of "*q" depends on the read of "p" and these
+ * two reads are separated by a read_barrier_depends().  However,
+ * the following code, with the same initial values for "a" and "b":
+ *
+ * <programlisting>
+ *      CPU 0                           CPU 1
+ *
+ *      a = 2;
+ *      memory_barrier();
+ *      b = 3;                          y = b;
+ *                                      read_barrier_depends();
+ *                                      x = a;
+ * </programlisting>
+ *
+ * does not enforce ordering, since there is no data dependency between
+ * the read of "a" and the read of "b".  Therefore, on some CPUs, such
+ * as Alpha, "y" could be set to 3 and "x" to 0.  Use rmb()
+ * in cases like this where there are no data dependencies.
+ */
+
+#define read_barrier_depends()  do { } while (0)
+
+#define __sync()        __insn_mf()
+
+#if CHIP_HAS_SPLIT_CYCLE()
+#define get_cycles_low() __insn_mfspr(SPR_CYCLE_LOW)
+#else
+#define get_cycles_low() __insn_mfspr(SPR_CYCLE)   /* just get all 64 bits */
+#endif
+
+/* Fence to guarantee visibility of stores to incoherent memory. */
+static inline void
+mb_incoherent(void)
+{
+        __insn_mf();
+
+#if !CHIP_HAS_MF_WAITS_FOR_VICTIMS()
+        {
+                int __mb_incoherent(void);
+#if CHIP_HAS_TILE_WRITE_PENDING()
+                const unsigned long WRITE_TIMEOUT_CYCLES = 400;
+                unsigned long start = get_cycles_low();
+                do {
+                        if (__insn_mfspr(SPR_TILE_WRITE_PENDING) == 0)
+                                return;
+                } while ((get_cycles_low() - start) < WRITE_TIMEOUT_CYCLES);
+#endif /* CHIP_HAS_TILE_WRITE_PENDING() */
+                (void) __mb_incoherent();
+        }
+#endif /* CHIP_HAS_MF_WAITS_FOR_VICTIMS() */
+}
+
+#define fast_wmb()      __sync()
+#define fast_rmb()      __sync()
+#define fast_mb()       __sync()
+#define fast_iob()      mb_incoherent()
+
+#define wmb()           fast_wmb()
+#define rmb()           fast_rmb()
+#define mb()            fast_mb()
+#define iob()           fast_iob()
+
+#ifdef CONFIG_SMP
+#define smp_mb()        mb()
+#define smp_rmb()       rmb()
+#define smp_wmb()       wmb()
+#define smp_read_barrier_depends()      read_barrier_depends()
+#else
+#define smp_mb()        barrier()
+#define smp_rmb()       barrier()
+#define smp_wmb()       barrier()
+#define smp_read_barrier_depends()      do { } while (0)
+#endif
+
+#define set_mb(var, value) \
+        do { var = value; mb(); } while (0)
+
+#include <linux/irqflags.h>
+
+/*
+ * Pause the DMA engine and static network before task switching.
+ */
+#define prepare_arch_switch(next) _prepare_arch_switch(next)
+void _prepare_arch_switch(struct task_struct *next);
+
+
+/*
+ * 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.
+ * The number of callee-saved registers saved on the kernel stack
+ * is defined here for use in copy_thread() and must agree with __switch_to().
+ */
+#endif /* !__ASSEMBLY__ */
+#define CALLEE_SAVED_FIRST_REG 30
+#define CALLEE_SAVED_REGS_COUNT 24   /* r30 to r52, plus an empty to align */
+#ifndef __ASSEMBLY__
+struct task_struct;
+#define switch_to(prev, next, last) ((last) = _switch_to((prev), (next)))
+extern struct task_struct *_switch_to(struct task_struct *prev,
+                                      struct task_struct *next);
+
+/*
+ * On SMP systems, when the scheduler does migration-cost autodetection,
+ * it needs a way to flush as much of the CPU's caches as possible:
+ *
+ * TODO: fill this in!
+ */
+static inline void sched_cacheflush(void)
+{
+}
+
+#define arch_align_stack(x) (x)
+
+/*
+ * Is the kernel doing fixups of unaligned accesses?  If <0, no kernel
+ * intervention occurs and SIGBUS is delivered with no data address
+ * info.  If 0, the kernel single-steps the instruction to discover
+ * the data address to provide with the SIGBUS.  If 1, the kernel does
+ * a fixup.
+ */
+extern int unaligned_fixup;
+
+/* Is the kernel printing on each unaligned fixup? */
+extern int unaligned_printk;
+
+/* Number of unaligned fixups performed */
+extern unsigned int unaligned_fixup_count;
+
+/* User-level DMA management functions */
+void grant_dma_mpls(void);
+void restrict_dma_mpls(void);
+
+
+/* Invoke the simulator "syscall" mechanism (see arch/tile/kernel/entry.S). */
+extern int _sim_syscall(int syscall_num, ...);
+#define sim_syscall(syscall_num, ...) \
+        _sim_syscall(SIM_CONTROL_SYSCALL + \
+                ((syscall_num) << _SIM_CONTROL_OPERATOR_BITS), \
+                ## __VA_ARGS__)
+
+/*
+ * Kernel threads can check to see if they need to migrate their
+ * stack whenever they return from a context switch; for user
+ * threads, we defer until they are returning to user-space.
+ */
+#define finish_arch_switch(prev) do {                                     \
+        if (unlikely((prev)->state == TASK_DEAD))                         \
+                __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_EXIT |       \
+                        ((prev)->pid << _SIM_CONTROL_OPERATOR_BITS));     \
+        __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_SWITCH |             \
+                (current->pid << _SIM_CONTROL_OPERATOR_BITS));            \
+        if (current->mm == NULL && !kstack_hash &&                        \
+            current_thread_info()->homecache_cpu != smp_processor_id())   \
+                homecache_migrate_kthread();                              \
+} while (0)
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* _ASM_TILE_SYSTEM_H */