On OMAP4+ devices, GIC register context is lost when MPUSS hits
the OSWR(Open Switch Retention). On the CPU wakeup path, ROM code
gets executed and one of the steps in it is to restore the
saved context of the GIC. The ROM Code GIC distributor restoration
is split in two parts: CPU specific register done by each CPU and
common register done by only one CPU.
Below is the abstract flow.
...............................................................
- MPUSS in OSWR state.
- CPU0 wakes up on the event(interrupt) and start executing ROM code.
[..]
- CPU0 executes "GIC Restoration:"
[...]
- CPU0 swicthes to non-secure mode and jumps to OS resume code.
[...]
- CPU0 is online in OS
- CPU0 enables the GIC distributor. GICD.Enable Non-secure = 1
- CPU0 wakes up CPU1 with clock-domain force wakeup method.
- CPU0 continues it's execution.
[..]
- CPU1 wakes up and start executing ROM code.
[..]
- CPU1 executes "GIC Restoration:"
[..]
- CPU1 swicthes to non-secure mode and jumps to OS resume code.
[...]
- CPU1 is online in OS and start executing.
[...] -
GIC Restoration: /* Common routine for HS and GP devices */
{
if (GICD != 1) { /* This will be true in OSWR state */
if (GIC_SAR_BACKUP_STATE == SAVED)
- CPU restores GIC distributor
else
- reconfigure GIC distributor to boot values.
GICD.Enable secure = 1
}
if (GIC_SAR_BACKUP_STATE == SAVED)
- CPU restore its GIC CPU interface registers if saved.
else
- reconfigure its GIC CPU interface registers to boot
values.
}
...............................................................
So as mentioned in the flow, GICD != 1 condition decides how
the GIC registers are handled in ROM code wakeup path from
OSWR. As evident from the flow, ROM code relies on the entire
GICD register value and not specific register bits.
The assumption was valid till CortexA9 r1pX version since there
was only one banked bit to control secure and non-secure GICD.
Secure view which ROM code sees:
bit 0 == Enable Non-secure
Non-secure view which HLOS sees:
bit 0 == Enable secure
But GICD register has changed between CortexA9 r1pX and r2pX.
On r2pX GICD register is composed of 2 bits.
Secure view which ROM code sees:
bit 1 == Enable Non-secure
bit 0 == Enable secure
Non-secure view which HLOS sees:
bit 0 == Enable Non-secure
Hence on OMAP4460(r2pX) devices, if you go through the
above flow again during CPU1 wakeup, GICD == 3 and hence
ROM code fails to understand the real wakeup power state
and reconfigures GIC distributor to boot values. This is
nasty since you loose the entire interrupt controller
context in a live system.
The ROM code fix done on next OMAP4 device (OMAP4470 - r2px) is to
check "GICD.Enable secure != 1" for GIC restoration in OSWR wakeup path.
Since ROM code can't be fixed on OMAP4460 devices, a work around
needs to be implemented. As evident from the flow, as long as
CPU1 sees GICD == 1 in it's wakeup path from OSWR, the issue
won't happen. Below is the flow with the work-around.
...............................................................
- MPUSS in OSWR state.
- CPU0 wakes up on the event(interrupt) and start executing ROM code.
[..]
- CPU0 executes "GIC Restoration:"
[..]
- CPU0 swicthes to non-secure mode and jumps to OS resume code.
[..]
- CPU0 is online in OS.
- CPU0 does GICD.Enable Non-secure = 0
- CPU0 wakes up CPU1 with clock domain force wakeup method.
- CPU0 waits for GICD.Enable Non-secure = 1
- CPU0 coninues it's execution.
[..]
- CPU1 wakes up and start executing ROM code.
[..]
- CPU1 executes "GIC Restoration:"
[..]
- CPU1 swicthes to non-secure mode and jumps to OS resume code.
[..]
- CPU1 is online in OS
- CPU1 does GICD.Enable Non-secure = 1
- CPU1 start executing
[...]
...............................................................
With this procedure, the GIC configuration done between the
CPU0 wakeup and CPU1 wakeup will not be lost but during this
short windows, the CPU0 will not receive interrupts.
The BUG is applicable to only OMAP4460(r2pX) devices.
OMAP4470 (also r2pX) is not affected by this bug because
ROM code has been fixed.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
Add OMAP5 SMP boot support using OMAP4 SMP code. The relevant code paths
are runtime checked using cpu id
Signed-off-by: R Sricharan <r.sricharan@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
WARNING: vmlinux.o(.text+0x1c664): Section mismatch in reference from the function omap_secondary_startup() to the function .cpuinit.text:secondary_startup()
The function omap_secondary_startup() references
the function __cpuinit secondary_startup().
This is often because omap_secondary_startup lacks a __cpuinit
annotation or the annotation of secondary_startup is wrong.
Unfortunately, fixing this causes a new warning which is harder to
solve:
WARNING: arch/arm/mach-omap2/built-in.o(.text+0x5328): Section mismatch in reference from the function omap4_hotplug_cpu() to the function .cpuinit.text:omap_secondary_startup()
The function omap4_hotplug_cpu() references
the function __cpuinit omap_secondary_startup().
This is often because omap4_hotplug_cpu lacks a __cpuinit
annotation or the annotation of omap_secondary_startup is wrong.
because omap4_hotplug_cpu() is used by power management code as well,
which may not end up using omap_secondary_startup().
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Remove the __INIT from omap_secondary_startup() so that it can
be re-used for CPU hotplug.
While at this, remove the un-used AUXBOOT register reference.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
Code marked with ENTRY() also needs a matching ENDPROC() directive,
in order to ensure that the type and instruction set of the
symbol are correctly annotated.
ENDPROC() tags the affected symbol as a function symbol, which will
ensure that link-time fixups don't accidentally switch to the
wrong instruction set.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
This patch adds a secure API to read AuxCoreBoot0 register to
check the cpu boot status. It also moves the other smc APIs
to common omap44xx-smc.S. This APIs should not be marked as
__INIT because we need these to be present for CPU hotplug
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
The AuxCoreBoot0 and AuxCoreBoot1 can be only accessed in secure
mode. Replace the current code with secure monitor API's to access/modify
these registers.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This patch adds SMP platform files support for OMAP4430SDP. TI's OMAP4430
SOC is based on ARM Cortex-A9 SMP architecture. It's a dual core SOC
with GIC used for interrupt handling and SCU for cache coherency.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Santosh Shilimkar