From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: add support for BCM2708/BCM2835 and Raspberry Pi
Date: Thu, 6 Sep 2012 09:04:14 +0000 [thread overview]
Message-ID: <201209060904.14903.arnd@arndb.de> (raw)
In-Reply-To: <1346908038-22421-1-git-send-email-swarren@wwwdotorg.org>
On Thursday 06 September 2012, Stephen Warren wrote:
> The BCM2708 is an ARM SoC from Broadcom. It is the primary SoC in a
> series which contains the BCM2835 amongst other variants. This patch
> adds very basic support for this series of SoCs, under the BCM2708 name.
Very nice!
> ---
> To do:
> * Interrupt controller and timer aren't implemented, so the kernel only
> boots as far as "Calibrating delay loop...". However, this patch is
> intended solely to provide the very basic infra-structure so people
> can start filling in the gaps in mainline rather than downstream.
> * No device drivers are implemented yet.
ok
> Questions:
> * It is asserted (I believe by Broadcom) that the BCM2835 is the only SoC
> in the series likely to see Linux support. Irrespective, those working
> on BCM2835 support downstream (see git URL above) have chosen to name
> the kernel support after the primary SoC (BCM2708) rather than the
> particular instance in use on the Raspberry Pi (BCM2835). I've followed
> that here, although I wonder if it's really the correct thing to do?
Doesn't matter too much. Depending on how different the various broadcom
SoCs actually are, we might even name this mach-bcm and eventually try to
merge the existing bcmring into it.
> * Should bcm2708_map_io() map the entire peripheral address range, or
> only the debug UART iff DEBUG_LL is enabled? Presumably anything other
> than the UART should be using of_iomap(), so doesn't need to be
> statically mapped; are the IRQ controller/timer set up before
> of_iomap() will work with non-static mappings?
Mapping the entire range is fine, as long as it's not too large. This
will end up using large pages for the mapping, which is a bit more efficient,
and any call to of_iomap or ioremap will just return the same address
rather than adding another mapping.
> * Does the (currently somewhat arbitrary) value for BCM2708_PERIPH_VIRT
> matter; should it be picked to align nicely with any particular part
> of the kernel's virtual address layout?
The only requirement is that it's inside of the vmalloc area described in
Documentation/arm/memory.txt. 0xf0000000 is fine here.
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 88ff698..3c11dce 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -349,6 +349,25 @@ config ARCH_AT91
> This enables support for systems based on Atmel
> AT91RM9200 and AT91SAM9* processors.
>
> +config ARCH_BCM2708
> + bool "Broadcom BCM2708 family"
> + select ARCH_WANT_OPTIONAL_GPIOLIB
> + select ARM_AMBA
> + select ARM_ERRATA_411920
> + select ARM_TIMER_SP804
> + select CLKDEV_LOOKUP
> + select COMMON_CLK
> + select CPU_V6
> + select GENERIC_CLOCKEVENTS
> + select MULTI_IRQ_HANDLER
> + select SPARSE_IRQ
> + select USE_OF
> + select WATCHDOG
All the good things are there, but normally one does not select WATCHDOG here.
> +CONFIG_SERIAL_8250=y
> +CONFIG_SERIAL_8250_CONSOLE=y
> +CONFIG_SERIAL_8250_NR_UARTS=48
> +CONFIG_SERIAL_8250_RUNTIME_UARTS=32
> +CONFIG_SERIAL_8250_EXTENDED=y
> +CONFIG_SERIAL_8250_MANY_PORTS=y
> +CONFIG_SERIAL_8250_SHARE_IRQ=y
> +CONFIG_SERIAL_AMBA_PL010=y
> +CONFIG_SERIAL_AMBA_PL010_CONSOLE=y
> +CONFIG_SERIAL_AMBA_PL011=y
> +CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
All three kinds of serial ports really?
> diff --git a/arch/arm/mach-bcm2708/common.c b/arch/arm/mach-bcm2708/common.c
> new file mode 100644
> index 0000000..85f19aa3
> --- /dev/null
> +++ b/arch/arm/mach-bcm2708/common.c
I think when this is the only file, we probably want to name this one bcm2708.c,
same as the platform.
> diff --git a/arch/arm/mach-bcm2708/include/mach/hardware.h b/arch/arm/mach-bcm2708/include/mach/hardware.h
> new file mode 100644
> index 0000000..2b15d0b
> --- /dev/null
> +++ b/arch/arm/mach-bcm2708/include/mach/hardware.h
No longer required.
> diff --git a/arch/arm/mach-bcm2708/include/mach/timex.h b/arch/arm/mach-bcm2708/include/mach/timex.h
> new file mode 100644
> index 0000000..ca67219
> --- /dev/null
> +++ b/arch/arm/mach-bcm2708/include/mach/timex.h
Very close to not being required any more, so you probably won't need it in 3.7.
Arnd
next prev parent reply other threads:[~2012-09-06 9:04 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-06 5:07 [PATCH] ARM: add support for BCM2708/BCM2835 and Raspberry Pi Stephen Warren
2012-09-06 9:04 ` Arnd Bergmann [this message]
2012-09-06 9:47 ` Domenico Andreoli
2012-09-06 15:46 ` Arnd Bergmann
2012-09-08 21:56 ` Russell King - ARM Linux
2012-09-09 0:30 ` Domenico Andreoli
2012-09-09 1:34 ` Arnd Bergmann
2012-09-09 0:52 ` Olof Johansson
2012-09-09 1:16 ` Arnd Bergmann
2012-09-09 8:46 ` Imre Kaloz
2012-09-07 2:23 ` Stephen Warren
2012-09-07 4:04 ` Arnd Bergmann
2012-09-06 16:53 ` Seth Jennings
2012-09-06 22:10 ` Simon Arlott
2012-09-07 0:56 ` Seth Jennings
2012-09-07 1:52 ` Stephen Warren
2012-09-08 17:12 ` popcornmix
2012-09-08 17:48 ` Stephen Warren
2012-09-08 17:53 ` popcornmix
2012-09-07 1:38 ` Stephen Warren
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