[PATCH v4 0/7] Enable L2 cache support on Exynos4210/4x12 SoCs

From: Tomasz Figa
Date: Tue Aug 26 2014 - 10:19:21 EST

This series intends to add support for L2 cache on Exynos4 SoCs on boards
running under secure firmware, which requires certain initialization steps
to be done with help of firmware, as selected registers are writable only
from secure mode.

First four patches extend existing support for secure write in L2C driver
to account for design of secure firmware running on Exynos. Namely:
1) direct read access to certain registers is needed on Exynos, because
secure firmware calls set several registers at once,
2) not all boards are running secure firmware, so .write_sec callback
needs to be installed in Exynos firmware ops initialization code,
3) write access to {DATA,TAG}_LATENCY_CTRL registers fron non-secure world
is not allowed and so must use l2c_write_sec as well,
4) on certain boards, default value of prefetch register is incorrect
and must be overridden at L2C initialization.
For boards running with firmware that provides access to individual
L2C registers this series should introduce no functional changes. However
since the driver is widely used on other platforms I'd like to kindly ask
any interested people for testing.

Further three patches add implementation of .write_sec and .configure
callbacks for Exynos secure firmware and necessary DT nodes to enable
L2 cache.

Changes in this version tested on Exynos4412-based TRATS2 board (with secure
firmware). There should be no functional change for Exynos boards running
without secure firmware. I do not have access to affected non-Exynos boards,
so I could not test on them.

Depends on:
- [PATCH v3 0/5] Firmware-assisted suspend/resume of Exynos SoCs

Changes since v3:
- fixed issues with references to initdata on resume path by creating
a copy of affected structure (pointed out by Russell King),
- fixed unnecessary full reconfiguration of L2C controller on resume
(configuration is already determined after initialization, so the
only thing to do is to push those values to the controller),
- rebased on next-20140717 tag of linux-next tree and last versions
of dependencies.

Changes since v2:
- refactored L2C driver to use commit-like interface and make it no longer
depend on availability of writes to individual registers,
- moved L2C resume to assembly code, because doing it later makes some
systems unstable - this is also needed for deeper cpuidle modes,
- dropped unnecessary patch hacking around the .write_sec interface,
- dropped patch making the driver use l2c_write_sec() for LATENCY_CTRL
registers as Exynos is no longer affected and I'm not aware of any
reports that this is also needed on other platforms (can be applied
separately if it turns out to be so),
- rebased onto next-20140717 tag of linux-next tree.

Changes since v1:
- rebased onto for-next branch of linux-samsung tree,
- changed argument order of outer_cache.write_sec() callback to match
l2c_write_sec() function in cache-l2x0.c,
- added support of overriding of prefetch settings to work around incorrect
default settings on certain Exynos4x12-based boards,
- added call to firmware to invalidate whole L2 cache before setting enable
bit in L2C control register (required by Exynos secure firmware).

Tomasz Figa (7):
ARM: l2c: Refactor the driver to use commit-like interface
ARM: l2c: Add interface to ask hypervisor to configure L2C
ARM: l2c: Get outer cache .write_sec callback from mach_desc only if
not NULL
ARM: l2c: Add support for overriding prefetch settings
ARM: EXYNOS: Add .write_sec outer cache callback for L2C-310
ARM: EXYNOS: Add support for non-secure L2X0 resume
ARM: dts: exynos4: Add nodes for L2 cache controller

Documentation/devicetree/bindings/arm/l2cc.txt | 10 +
arch/arm/boot/dts/exynos4210.dtsi | 9 +
arch/arm/boot/dts/exynos4x12.dtsi | 14 ++
arch/arm/include/asm/outercache.h | 3 +
arch/arm/kernel/irq.c | 3 +-
arch/arm/mach-exynos/common.h | 1 +
arch/arm/mach-exynos/firmware.c | 42 +++-
arch/arm/mach-exynos/sleep.S | 41 ++++
arch/arm/mm/cache-l2x0.c | 255 ++++++++++++++++---------
9 files changed, 281 insertions(+), 97 deletions(-)


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