arch: remove tile port

The Tile architecture port was added by Chris Metcalf in 2010, and
maintained until early 2018 when he orphaned it due to his departure
from Mellanox, and nobody else stepped up to maintain it. The product
line is still around in the form of the BlueField SoC, but no longer
uses the Tile architecture.

There are also still products for sale with Tile-GX SoCs, notably the
Mikrotik CCR router family. The products all use old (linux-3.3) kernels
with lots of patches and won't be upgraded by their manufacturers. There
have been efforts to port both OpenWRT and Debian to these, but both
projects have stalled and are very unlikely to be continued in the future.

Given that we are reasonably sure that nobody is still using the port
with an upstream kernel any more, it seems better to remove it now while
the port is in a good shape than to let it bitrot for a few years first.

Cc: Chris Metcalf <chris.d.metcalf@gmail.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: http://www.mellanox.com/page/npu_multicore_overview
Link: https://jenkins.debian.net/view/rebootstrap/job/rebootstrap_tilegx_gcc7/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 0 insertions, 64 deletions

diff --git a/arch/tile/lib/spinlock_common.h b/arch/tile/lib/spinlock_common.h
deleted file mode 100644
index 6ac37509faca..000000000000
--- a/arch/tile/lib/spinlock_common.h
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * 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.
- * This file is included into spinlock_32.c or _64.c.
- */
-
-/*
- * The mfspr in __spinlock_relax() is 5 or 6 cycles plus 2 for loop
- * overhead.
- */
-#ifdef __tilegx__
-#define CYCLES_PER_RELAX_LOOP 7
-#else
-#define CYCLES_PER_RELAX_LOOP 8
-#endif
-
-/*
- * Idle the core for CYCLES_PER_RELAX_LOOP * iterations cycles.
- */
-static inline void
-relax(int iterations)
-{
-	for (/*above*/; iterations > 0; iterations--)
-		__insn_mfspr(SPR_PASS);
-	barrier();
-}
-
-/* Perform bounded exponential backoff.*/
-static void delay_backoff(int iterations)
-{
-	u32 exponent, loops;
-
-	/*
-	 * 2^exponent is how many times we go around the loop,
-	 * which takes 8 cycles.  We want to start with a 16- to 31-cycle
-	 * loop, so we need to go around minimum 2 = 2^1 times, so we
-	 * bias the original value up by 1.
-	 */
-	exponent = iterations + 1;
-
-	/*
-	 * Don't allow exponent to exceed 7, so we have 128 loops,
-	 * or 1,024 (to 2,047) cycles, as our maximum.
-	 */
-	if (exponent > 8)
-		exponent = 8;
-
-	loops = 1 << exponent;
-
-	/* Add a randomness factor so two cpus never get in lock step. */
-	loops += __insn_crc32_32(stack_pointer, get_cycles_low()) &
-		(loops - 1);
-
-	relax(loops);
-}