It was found that the L2 cache timings that we had before could cause
freezes and hangs. We should make things more robust with better
timings. Currently the production ChromeOS kernel applies these
timings, but it's nice to fixup firmware too (and upstream probably
won't take our kernel hacks).
This also provides a big cleanup of the L2 cache init code avoiding
some duplication. The way things used to work:
* low_power_start() was installed by the SPL (both at boot and resume
time) and left resident in iRAM for the kernel to use when bringing
up additional CPUs. It used configure_l2_ctlr() and
configure_l2_actlr() when it detected it was on an A15. This was
needed (despite the L2 cache registers being shared among all A15s)
because we might have been the first man in after the whole A15
cluster was shutdown.
* secondary_cores_configure() was called on at boot time and at resume
time. Strangely this called configure_l2_ctlr() but not
configure_l2_actlr() which was almost certainly wrong. Given that
we'll call both (see next bullet) later in the boot process it
didn't matter for normal boot, but I guess this is how L2 cache
settings got set on 5420/5800 (but not 5250?) at resume time.
* exynos5_set_l2cache_params() was called as part of cache enablement.
This should happen at boot time (normally in the SPL except for USB
boot where it happens in main U-Boot).
Note that the old code wasn't setting ECC/parity in the cache
enablement code but we happened to get it anyway because we'd call
secondary_cores_configure() at boot time. For resume time we'd get it
anyway when the 2nd A15 core came up.
Let's make this a whole lot simpler. Now we always set these
parameters in the same place for all boots and use the same code for
setting up secondary CPUs.
Intended net effects of this change (other than cleanup):
* Timings go from before:
data: 0 cycle setup, 3 cycles (0x2) latency
tag: 0 cycle setup, 3 cycles (0x2) latency
after:
data: 1 cycle setup, 4 cycles (0x3) latency
tag: 1 cycle setup, 4 cycles (0x3) latency
* L2ACTLR is properly initted on 5420/5800 in all cases.
One note is that we're still relying on luck to keep low_power_start()
working. The compiler is being nice and not storing anything on the
stack.
Another note is that on its own this patch won't help to fix cache
settings in an RW U-Boot update where we still have the RO SPL. The
plan for that is:
* Have RW U-Boot re-init the cache right before calling the kernel
(after it has turned the L2 cache off). This is why the functions
are in a header file instead of lowlevel_init.c.
* Have the kernel save the L2 cache settings of the boot CPU and apply
them to all other CPUs. We get a little lucky here because the old
code was using "|=" to modify the registers and all of the bits that
it's setting are also present in the new settings (!). That means
that when the 2nd CPU in the A15 cluster comes up it doesn't
actually mess up the settings of the 1st CPU in the A15 cluster. An
alternative option is to have the kernel write its own
low_power_start() code.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
When compiled SPL for Thumb secondary cores failed to boot
at the kernel boot up. Only one core came up out of 4.
This was happening because the code relocated to the
address 0x02073000 by the primary core was an ARM asm
code which was executed by the secondary cores as if it
was a thumb code.
This patch fixes the issue of secondary cores considering
relocated code as Thumb instructions and not ARM instructions
by jumping to the relocated with the help of "bx" ARM instruction.
"bx" instruction changes the 5th bit of CPSR which allows
execution unit to consider the following instructions as ARM
instructions.
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
This patch adds code to shutdown secondary cores.
When U-boot comes up, all secondary cores appear powered on,
which is undesirable and causes side effects while
initializing these cores in kernel.
Secondary core power down happens in following steps:
Step-1: After Exynos power-on, primary core starts executing first.
Step-2: In iROM code every core has to check 2 flags i.e.
addresses 0x02020028 & 0x02020004.
Step-3: Initially 0x02020028 is 0 for all cores and 0x02020004 has a
jump address for primary core and 0 for all secondary cores.
Step-4: Therefore, primary core follows normal iROM execution and jumps
to BL1 eventually, whereas all secondary cores enter WFE.
Step-5: When primary core comes into function secondary_cores_configure,
it puts pointer to function power_down_core into 0x02020004
and provides DSB and SEV for all cores so that they may come out
of WFE and jump to power_down_core function.
Step-6: And ultimately because of power_down_core all
secondary cores shut-down.
Signed-off-by: Kimoon Kim <kimoon.kim@samsung.com>
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
Not all exynos 5420 based devices with an LCD also have a parade LVDS
bridge. So make sure compilation doesn't break if CONFIG_LCD is enabled
and CONFIG_VIDEO_PARADE is not.
As a side-effect move the parade functions from the exynos system header
file to its own file.
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
Previously, we used to statically assign values for vl_col, vl_row and
vl_bpix using #defines like LCD_XRES, LCD_YRES and LCD_COLOR16.
Introducing the function exynos_lcd_early_init() would take care of this
assignment on the fly by parsing FIMD DT properties, thereby allowing us
to remove LCD_XRES and LCD_YRES from the main config file.
Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
This patch corrects the SYSREG structure.
We have removed the sysreg.h added in the previous patchset
version as the sysreg structure is already defined in system.h.
Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Acked-by: Minkyu Kang <mk7.kang@samsung.com>
This is definitions of system registers and power mananagement registers for EXYNOS SoC.
Signed-off-by: Donghwa Lee <dh09.lee@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
