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>
On warm reset, all cores jump to the low_power_start function because iRAM
data is retained and because while executing iROM code all cores find
the jump flag 0x02020028 set. In low_power_start, cores check the reset
status and if true they clear the jump flag and jump back to 0x0.
The A7 cores do jump to 0x0 but consider following instructions as a Thumb
instructions which in turn makes them loop inside the iROM code instead of
jumping to power_down_core.
This issue is fixed by replacing the "mov pc" instruction with a "bx"
instruction which switches state along with the jump to make the execution
unit consider the branch target as an ARM instruction.
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>
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 does 3 things:
1. Enables ECC by setting 21st bit of L2CTLR.
2. Restore data and tag RAM latencies to 3 cycles because iROM sets
0x3000400 L2CTLR value during switching.
3. Disable clean/evict push to external by setting 3rd bit of L2ACTLR.
We need to restore this here due to switching.
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
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>
iROM logic provides undesired jump address for CPU2.
This patch adds a programmable susbstitute for a part of
iROM logic which wakes up cores and provides jump addresses.
This patch creates a logic to make all secondary cores jump
to a particular address which evades the possibility of CPU2
jumping to wrong address and create undesired results.
Logic of the workaround:
Step-1: iROM code checks value at address 0x2020028.
Step-2: If value is 0xc9cfcfcf, it jumps to the address (0x202000+CPUid*4),
else, it continues executing normally.
Step-3: Primary core puts secondary cores in WFE and store 0xc9cfcfcf in
0x2020028 and jump address (pointer to function low_power_start)
in (0x202000+CPUid*4).
Step-4: When secondary cores recieve event signal they jump to this address
and continue execution.
Signed-off-by: Kimoon Kim <kimoon.kim@samsung.com>
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>
Setting ps_hold ought to be one of the first things we do when we
first boot up. If we wait until the main u-boot runs we won't set it
in time and the PMIC may power us back off.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
There is quite a tight deadline in enabling PSHOLD, less than a second.
In some cases (e.g. with USB download), U-Boot takes longer than that
to load, so the board powers off before U-Boot starts.
Add a call in SPL to enable PSHOLD.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
This patch performs the following:
1) Convert the assembly code for memory and clock initialization to C code.
2) Move the memory and clock init codes from board/samsung to arch/arm
3) Creat a common lowlevel_init file across Exynos4 and Exynos5. Converted
the common lowlevel_init from assembly to C-code
4) Made spl_boot.c and tzpc_init.c common for both exynos4 and exynos5.
5) Enable CONFIG_SKIP_LOWLEVEL_INIT as stack pointer initialisation is already
done in _main.
6) exynos-uboot-spl.lds made common across SMDKV310, Origen and SMDK5250.
TEST: Tested SD-MMC boot on SMDK5250 and Origen.
Tested USB and SPI boot on SMDK5250
Compile tested for SMDKV310.
Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
