During the review process of the UniPhier System Bus driver
(drivers/bus/uniphier.c), the current binding of the System Bus
Controller turned out to be no good. In order to use the driver,
some nodes in the device trees must be tweaked. It would also have
impacts on the SMP code because the SMP related registers are
located in the System Bus Controller block. This commit reworks
the smp_operations to support the new binding, but still supports
the old binding, too.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This node pointer is allocated by of_find_compatible_node() in this
function. It should be put before exitting this function.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Merge in cleanup to avoid internal conflicts with newly added code.
* treewide/cleanup:
ARM: use "depends on" for SoC configs instead of "if" after prompt
ARM/clocksource: use automatic DT probing for ux500 PRCMU
ARM: use const and __initconst for smp_operations
ARM: hisi: do not export smp_operations structures
Signed-off-by: Olof Johansson <olof@lixom.net>
The UniPhier SoCs support pinctrl drivers.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
The complexity of the boot sequence of UniPhier SoC family is
a PITA due to the following hardware limitations:
[1] No dedicated on-chip SRAM
SoCs in general have small SRAM, on which a tiny firmware or a boot
loader can run before SDRAM is initialized. As UniPhier SoCs do not
have any dedicated SRAM accessible from CPUs, the locked outer cache
is used instead. Due to the ARM specification, to have access to
the outer cache, the MMU must be enabled. This is done for all CPU
cores by the program hard-wired in the boot ROM. The boot ROM code
loads a small amount of program (this is usually SPL of U-Boot) from
a non-volatile device onto the locked outer cache, and the primary
CPU jumps to it. The secondary CPUs stay in the boot ROM until they
are kicked by the primary CPU.
[2] CPUs can not directly jump to SDRAM address space
As mentioned above, the MMU is enable for all the CPUs with the page
table hard-wired in the boot ROM. Unfortunately, the page table only
has minimal sets of valid sections; all the sections of SDRAM address
space are zero-filled. That means all the CPUs, including secondary
ones, can not jump directly to SDRAM address space. So, the primary
CPU must bring up secondary CPUs to accessible address mapped onto
the outer cache, then again kick them to SDRAM address space.
Before this commit, this complex task was done with help of a boot
loader (U-Boot); U-Boot SPL brings up the secondary CPUs to the entry
of U-Boot SPL and they stay there until they are kicked by Linux.
This is not nice because a boot loader must put the secondary CPUs
into a certain state expected by the kernel. It makes difficult to
port another boot loader because the boot loader and the kernel must
work in sync to wake up the secondary CPUs.
This commit reworks the SMP operations so that they do not rely on
particular boot loader implementation; the SMP operations (platsmp.c)
put trampoline code (headsmp.S) on a locked way of the outer cache.
The secondary CPUs jump from the boot ROM to secondary_entry via the
trampoline code. The boot loader no longer needs to take care of SMP.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
This is unnecessary since commit 02b4e2756e ("ARM: v7 setup
function should invalidate L1 cache").
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
This makes uniphier behave like all the other platforms that
support TWD, and only select this driver when SMP is enabled.
Without this, we get a compile error on UP builds:
arch/arm/kernel/smp_twd.c: In function 'twd_local_timer_of_register':
arch/arm/kernel/smp_twd.c:391:20: error: 'setup_max_cpus' undeclared (first use in this function)
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Initial commit for a new SoC family, UniPhier, developed by
Socionext Inc. (formerly, System LSI Business Division of
Panasonic Corporation).
This commit includes a minimal set of components for booting the
kernel, including SMP support.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
