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The bcm283x chips provide a way for the ARM core to communicate with the
graphics processor, which is in charge of many things. This is handled by
way of a message prototcol.
At present the code for sending message (and receiving a reply) is spread
around U-Boot, primarily in the board file. This means that sending a
message from a driver requires duplicating the code.
Create a new message implementation with a function to support powering on
a subsystem as a starting point.
Signed-off-by: Simon Glass <sjg@chromium.org>
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Now that rpi_*defconfig and Kconfig (rather than the config header file)
provide the identity of the build, we don't need to separate config
headers and board directories for each RPi variant. Set CONFIG_SYS_BOARD
and CONFIG_SYS_CONFIG_NAME so that we can get rid of the duplication. This
requires a tiny number of extra ifdefs in the config header.
The only disadvantage of this approach is that the $board/$board_name
environment variables aren't as descriptive as they used to be. This isn't
really an issue because those only exist to allow scripts to create DTB
filenames at runtime. However, the RPi board code already sets $fdtfile to
something more accurate based on FW-reported board ID anyway.
While at it, unify some Kconfig select options, and add a MAINTAINERS
entry for bcm283x too.
Partially-suggested-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
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Switch to generic timer implementation from lib/time.c .
This also fixes a signed overflow which was in __udelay()
implementation.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Tyler Baker <tyler.baker@linaro.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
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The BCM283[56] contain both a L1 and L2 cache between the GPU (a/k/a
VideoCore CPU?) and DRAM. DMA-capable peripherals can also optionally
access DRAM via this same L2 cache (although they always bypass the L1
cache). Peripherals select whether to use or bypass the cache via the
top two bits of the bus address.
An IOMMU exists between the ARM CPU and the rest of the system. This
controls whether the ARM CPU's accesses use or bypass the L1 and/or L2
cache. This IOMMU is configured/controlled exclusively by the VideoCore
CPU.
In order for DRAM accesses made by the ARM core to be coherent with
accesses made by other DMA peripherals, we must program a bus address
into those peripherals that causes the peripheral's accesses to use the
same set of caches that the ARM core's accesses will use.
On the RPi1, the VideoCore firmware sets up the IOMMU to enable use of
the L2 cache. This corresponds to addresses based at 0x40000000.
On the RPi2, the VideoCore firmware sets up the IOMMU to disable use of
the L2 cache. This corresponds to addresses based at 0xc0000000.
This patch implements U-Boot's phys_to_bus/bus_to_phys APIs according
to those rules.
For full details of this setup, please see Dom Cobley's description at:
http://lists.denx.de/pipermail/u-boot/2015-March/208201.html
http://permalink.gmane.org/gmane.comp.boot-loaders.u-boot/215038
https://www.mail-archive.com/u-boot@lists.denx.de/msg166568.html
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
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BCM2835 (used on Raspberry Pi) and BCM2836 (used on Raspberry Pi 2)
are similar enough. One of the biggest differences is the ARM
processor. It is reasonable to collect the source files into a
single place, arch/arm/mach-bcm283x/.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
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