Commit Graph

4 Commits

Author SHA1 Message Date
Julius Werner fd9defc0ca arm: Redesign, clarify and clean up cache related code
This patch changes several cache-related pieces to be cleaner, faster or
more correct. The largest point is removing the old
arm_invalidate_caches() function and surrounding bootblock code to
initialize SCTLR and replace it with an all-assembly function that takes
care of cache and SCTLR initialization to bring the system to a known
state. It runs without stack and before coreboot makes any write
accesses to be as compatible as possible with whatever state the system
was left in by preceeding code. This also finally fixes the dreaded
icache bug that wasted hundreds of milliseconds during boot.

Old-Change-Id: I7bb4995af8184f6383f8e3b1b870b0662bde8bd4
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/183890
(cherry picked from commit 07a35925dc957919bf88dfc90515971a36e81b97)

nyan_big: apply cache-related changes from nyan

This applies the same changes from 07a3592 that were applied to nyan.

Old-Change-Id: Idcbe85436d7a2f65fcd751954012eb5f4bec0b6c
Reviewed-on: https://chromium-review.googlesource.com/184551
Commit-Queue: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit 4af27f02614da41c611aee2c6d175b1b948428ea)

Squashed the followup patch for nyan_big into the original patch.

Change-Id: Id14aef7846355ea2da496e55da227b635aca409e
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
(cherry picked from commit 4cbf25f8eca3a12bbfec5b015953c0fc2b69c877)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>
Reviewed-on: http://review.coreboot.org/6993
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2014-11-10 21:34:49 +01:00
Julius Werner e9e31892d2 libpayload: Add missing cache API stub to x86
This patch adds another cache invalidation stub to the x86 arch to
make it usable in common code. This whole stuff should probably be
redesigned anyway but I just want to get it working and unblock my CL
for now... more cleanups coming later.

Change-Id: I2e8bdd8aa0e6723209384c24042f053f2e993fe6
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/182534
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
(cherry picked from commit cafce5182a7a2a9ce17ad40d9d893a40ebd5aafd)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6919
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2014-09-25 18:33:07 +02:00
Julius Werner 509c37e750 libpayload: Make EHCI driver cache-aware
This patch makes the EHCI driver work on ARM platforms which usually do
not support automatic cache snooping. It uses the new DMA memory
mechanism (which needs to be correctly set up in the Coreboot mainboard
code) to allocate all EHCI-internal communication structures in
cache-coherent memory, and cleans/invalidates the externally supplied
transfer buffers in Bulk and Control functions with explicit calls as
necessary.

Old-Change-Id: Ie8a62545d905b7a4fdd2a56b9405774be69779e5
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/167339
(cherry picked from commit 322338934add36a5372ffe7d2a45e61a4fdd4a54)

libpayload: ehci: Cache management is hard, let's go copying...

It turns out that my previous commit to make the EHCI stack cache aware
on ARM devices wasn't quite correct, and the problem is actually much
trickier than I thought. After having some fun with more weird transfer
problems that appear/disappear based on stack alignment, this is my
current worst-case threat model that any cache managing implementation
would need to handle correctly:

Some upper layer calls ehci_bulk() with a transfer buffer on its stack.
Due to stack alignment, it happens to start just at the top of a cache
line, so up to 64 - 4 bytes of ehci_bulk's stack will share that line.
ehci_bulk() calls dcache_clean() and initializes the USB transfer.
Between that point and the call to dcache_invalidate() at the end of
ehci_bulk(), any access to the stack variables in that cache line (even
a speculative prefetch) will refetch the line into the cache. Afterwards
any other access to a random memory location that just happens to get
aliased to the same cache line may evict it again, causing the processor
to write out stale data to the transfer buffer and possibly overwrite
data that has already been received over USB.

In short, any dcache_clean/dcache_invalidate-based implementation that
preserves correctness while allowing any arbitrary (non cache-aligned)
memory location as a transfer buffer is presumed to be impossible.
Instead, this patch causes all transfer data to be copied to/from a
cache-coherent bounce buffer. It will still transfer directly if the
supplied buffer is already cache-coherent, which can be used by callers
to optimize their transfers (and is true by default on x86).

Old-Change-Id: I112908410bdbc8ca028d44f2f5d388c529f8057f
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/169231
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
(cherry picked from commit 702dc50f1d56fe206442079fa443437f4336daed)

Squashed the initial commit and a follow up fix.

Change-Id: Idf7e5aa855b4f0221f82fa380a76049f273e4c88
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6633
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2014-08-14 23:40:25 +02:00
Stefan Reinauer b86062959b libpayload: Have similar cache api on ARM and x86
So far this is used by the USB driver, and instead of
having ifdefs all throughout that code, implement the same
API on x86 and ARM.

Change-Id: I8093ad818ad2e38a0901787aa8674faf591d580c
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/56105
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Commit-Queue: Stefan Reinauer <reinauer@chromium.org>
Tested-by: Stefan Reinauer <reinauer@chromium.org>
Reviewed-on: http://review.coreboot.org/4320
Tested-by: build bot (Jenkins)
2013-12-05 20:11:39 +01:00