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authorJulius Werner <jwerner@chromium.org>2014-01-13 11:13:23 -0800
committerIsaac Christensen <isaac.christensen@se-eng.com>2014-09-29 17:26:22 +0200
commit12de698c248e52a14cbb56f5fc3c4598115d72ef (patch)
treeab0ea31e19ab18d74ee2dc6523bef728c0d760be /src/arch/arm
parent81f90c58d2eacf8ee2baf2334fd38bbfa0ef7274 (diff)
downloadcoreboot-12de698c248e52a14cbb56f5fc3c4598115d72ef.tar.xz
arm: Import armv7_dcache_wbinv_all function from NetBSD
This patch pulls in NetBSD's full cache flushing algorithm for ARM, to replace our old, slow and slightly overzealous C-only implementation. It's a beautiful piece of code that manages to run on only caller-saved registers (meaning it doesn't need to write to memory) in a very tight loop, and it's BSD-licensed to boot (which we need for libpayload). Unfortunately it's also not quite correct, but I can fix that. Pulling the original in a separate commit to make it more obvious what changes are mine. Change-Id: I7a71c9e570866a6e25f756cb09ae2b6445048d83 Signed-off-by: Julius Werner <jwerner@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/183878 Reviewed-by: Stefan Reinauer <reinauer@google.com> Reviewed-by: Vincent Palatin <vpalatin@chromium.org> Reviewed-by: David Hendricks <dhendrix@chromium.org> (cherry picked from commit 4698467320613d7ddc39714f40aacbc990af9399) Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com> Reviewed-on: http://review.coreboot.org/6931 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
Diffstat (limited to 'src/arch/arm')
-rw-r--r--src/arch/arm/armv7/cpu.S99
1 files changed, 99 insertions, 0 deletions
diff --git a/src/arch/arm/armv7/cpu.S b/src/arch/arm/armv7/cpu.S
new file mode 100644
index 0000000000..42e2354d44
--- /dev/null
+++ b/src/arch/arm/armv7/cpu.S
@@ -0,0 +1,99 @@
+/*
+ * Optimized assembly for low-level CPU operations on ARMv7 processors.
+ *
+ * Cache flushing code based off sys/arch/arm/arm/cpufunc_asm_armv7.S in NetBSD
+ *
+ * Copyright (c) 2010 Per Odlund <per.odlund@armagedon.se>
+ * Copyright (c) 2014 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * These work very hard to not push registers onto the stack and to limit themselves
+ * to use r0-r3 and ip.
+ */
+
+/* * LINTSTUB: void armv7_dcache_wbinv_all(void); */
+ENTRY_NP(armv7_dcache_wbinv_all)
+ mrc p15, 1, r0, c0, c0, 1 @ read CLIDR
+ ands r3, r0, #0x07000000
+ beq .Ldone_wbinv
+ lsr r3, r3, #23 @ left align loc (low 4 bits)
+
+ mov r1, #0
+.Lstart_wbinv:
+ add r2, r3, r3, lsr #1 @ r2 = level * 3 / 2
+ mov r1, r0, lsr r2 @ r1 = cache type
+ bfc r1, #3, #28
+ cmp r1, #2 @ is it data or i&d?
+ blt .Lnext_level_wbinv @ nope, skip level
+
+ mcr p15, 2, r3, c0, c0, 0 @ select cache level
+ isb
+ mrc p15, 1, r0, c0, c0, 0 @ read CCSIDR
+
+ ubfx ip, r0, #0, #3 @ get linesize from CCSIDR
+ add ip, ip, #4 @ apply bias
+ ubfx r2, r0, #13, #15 @ get numsets - 1 from CCSIDR
+ lsl r2, r2, ip @ shift to set position
+ orr r3, r3, r2 @ merge set into way/set/level
+ mov r1, #1
+ lsl r1, r1, ip @ r1 = set decr
+
+ ubfx ip, r0, #3, #10 @ get numways - 1 from [to be discarded] CCSIDR
+ clz r2, ip @ number of bits to MSB of way
+ lsl ip, ip, r2 @ shift by that into way position
+ mov r0, #1 @
+ lsl r2, r0, r2 @ r2 now contains the way decr
+ mov r0, r3 @ get sets/level (no way yet)
+ orr r3, r3, ip @ merge way into way/set/level
+ bfc r0, #0, #4 @ clear low 4 bits (level) to get numset - 1
+ sub r2, r2, r0 @ subtract from way decr
+
+ /* r3 = ways/sets/level, r2 = way decr, r1 = set decr, r0 and ip are free */
+1: mcr p15, 0, r3, c7, c14, 2 @ writeback and invalidate line
+ cmp r3, #15 @ are we done with this level (way/set == 0)
+ bls .Lnext_level_wbinv @ yes, go to next level
+ lsl r0, r3, #10 @ clear way bits leaving only set/level bits
+ lsr r0, r0, #4 @ clear level bits leaving only set bits
+ subne r3, r3, r1 @ non-zero?, decrement set #
+ subeq r3, r3, r2 @ zero?, decrement way # and restore set count
+ b 1b
+
+.Lnext_level_wbinv:
+ mrc p15, 1, r0, c0, c0, 1 @ read CLIDR
+ and ip, r0, #0x07000000 @ narrow to LoC
+ lsr ip, ip, #23 @ left align LoC (low 4 bits)
+ add r3, r3, #2 @ go to next level
+ cmp r3, ip @ compare
+ blt .Lstart_wbinv @ not done, next level (r0 == CLIDR)
+
+.Ldone_wbinv:
+ mov r0, #0 @ default back to cache level 0
+ mcr p15, 2, r0, c0, c0, 0 @ select cache level
+ dsb
+ isb
+ bx lr
+END(armv7_dcache_wbinv_all)