c6x: remove architecture

The c6x architecture was added to the kernel in 2011 at a time when
running Linux on DSPs was widely seen as the logical evolution.
It appears the trend has gone back to running Linux on Arm based SoCs
with DSP, using a better supported software ecosystem, and having better
real-time behavior for the DSP code. An example of this is TI's own
Keystone2 platform.

The upstream kernel port appears to no longer have any users. Mark
Salter remained avaialable to review patches, but mentioned that
he no longer has access to working hardware himself. Without any
users, it's best to just remove the code completely to reduce the
work for cross-architecture code changes.

Many thanks to Mark for maintaining the code for the past ten years.

Link: https://lore.kernel.org/lkml/41dc7795afda9f776d8cd0d3075f776cf586e97c.camel@redhat.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 0 insertions, 86 deletions

diff --git a/arch/c6x/lib/divu.S b/arch/c6x/lib/divu.S
deleted file mode 100644
index f0f6082944c2..000000000000
--- a/arch/c6x/lib/divu.S
+++ /dev/null
@@ -1,86 +0,0 @@
-;; SPDX-License-Identifier: GPL-2.0-or-later
-;;  Copyright 2010  Free Software Foundation, Inc.
-;;  Contributed by Bernd Schmidt <bernds@codesourcery.com>.
-;;
-
-#include <linux/linkage.h>
-
-	;; ABI considerations for the divide functions
-	;; The following registers are call-used:
-	;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5
-	;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4
-	;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4
-	;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4
-	;;
-	;; In our implementation, divu and remu are leaf functions,
-	;; while both divi and remi call into divu.
-	;; A0 is not clobbered by any of the functions.
-	;; divu does not clobber B2 either, which is taken advantage of
-	;; in remi.
-	;; divi uses B5 to hold the original return address during
-	;; the call to divu.
-	;; remi uses B2 and A5 to hold the input values during the
-	;; call to divu.  It stores B3 in on the stack.
-
-	.text
-ENTRY(__c6xabi_divu)
-	;; We use a series of up to 31 subc instructions.  First, we find
-	;; out how many leading zero bits there are in the divisor.  This
-	;; gives us both a shift count for aligning (shifting) the divisor
-	;; to the, and the number of times we have to execute subc.
-
-	;; At the end, we have both the remainder and most of the quotient
-	;; in A4.  The top bit of the quotient is computed first and is
-	;; placed in A2.
-
-	;; Return immediately if the dividend is zero.
-	 mv	.s2x	A4, B1
-   [B1]	 lmbd	.l2	1, B4, B1
-|| [!B1] b	.s2	B3	; RETURN A
-|| [!B1] mvk	.d2	1, B4
-	 mv	.l1x	B1, A6
-||	 shl	.s2	B4, B1, B4
-
-	;; The loop performs a maximum of 28 steps, so we do the
-	;; first 3 here.
-	 cmpltu	.l1x	A4, B4, A2
-   [!A2] sub	.l1x	A4, B4, A4
-||	 shru	.s2	B4, 1, B4
-||	 xor	.s1	1, A2, A2
-
-	 shl	.s1	A2, 31, A2
-|| [B1]	 subc	.l1x	A4,B4,A4
-|| [B1]	 add	.s2	-1, B1, B1
-   [B1]	 subc	.l1x	A4,B4,A4
-|| [B1]	 add	.s2	-1, B1, B1
-
-	;; RETURN A may happen here (note: must happen before the next branch)
-_divu_loop:
-	 cmpgt	.l2	B1, 7, B0
-|| [B1]	 subc	.l1x	A4,B4,A4
-|| [B1]	 add	.s2	-1, B1, B1
-   [B1]	 subc	.l1x	A4,B4,A4
-|| [B1]	 add	.s2	-1, B1, B1
-|| [B0]  b	.s1	_divu_loop
-   [B1]	 subc	.l1x	A4,B4,A4
-|| [B1]	 add	.s2	-1, B1, B1
-   [B1]	 subc	.l1x	A4,B4,A4
-|| [B1]	 add	.s2	-1, B1, B1
-   [B1]	 subc	.l1x	A4,B4,A4
-|| [B1]	 add	.s2	-1, B1, B1
-   [B1]	 subc	.l1x	A4,B4,A4
-|| [B1]	 add	.s2	-1, B1, B1
-   [B1]	 subc	.l1x	A4,B4,A4
-|| [B1]	 add	.s2	-1, B1, B1
-	;; loop backwards branch happens here
-
-	 ret	.s2	B3
-||	 mvk	.s1	32, A1
-	 sub	.l1	A1, A6, A6
-	 shl	.s1	A4, A6, A4
-	 shru	.s1	A4, 1, A4
-||	 sub	.l1	A6, 1, A6
-	 or	.l1	A2, A4, A4
-	 shru	.s1	A4, A6, A4
-	 nop
-ENDPROC(__c6xabi_divu)