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r: 234846
b: refs/heads/master
c: 275a88d
h: refs/heads/master
v: v3
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Ingo Molnar committed Feb 16, 2011
1 parent c3e2d32 commit 98b281f
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: 9e81509efc4fefcdd75cc6a4121672fa71ae8745
refs/heads/master: 275a88d3cf0e2f08a98dc5ce9494af0cb6ed2092
25 changes: 25 additions & 0 deletions trunk/Documentation/ABI/testing/sysfs-platform-at91
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What: /sys/devices/platform/at91_can/net/<iface>/mb0_id
Date: January 2011
KernelVersion: 2.6.38
Contact: Marc Kleine-Budde <kernel@pengutronix.de>
Description:
Value representing the can_id of mailbox 0.

Default: 0x7ff (standard frame)

Due to a chip bug (errata 50.2.6.3 & 50.3.5.3 in
"AT91SAM9263 Preliminary 6249H-ATARM-27-Jul-09") the
contents of mailbox 0 may be send under certain
conditions (even if disabled or in rx mode).

The workaround in the errata suggests not to use the
mailbox and load it with an unused identifier.

In order to use an extended can_id add the
CAN_EFF_FLAG (0x80000000U) to the can_id. Example:

- standard id 0x7ff:
echo 0x7ff > /sys/class/net/can0/mb0_id

- extended id 0x1fffffff:
echo 0x9fffffff > /sys/class/net/can0/mb0_id
33 changes: 29 additions & 4 deletions trunk/Documentation/arm/Booting
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Expand Up @@ -65,13 +65,19 @@ looks at the connected hardware is beyond the scope of this document.
The boot loader must ultimately be able to provide a MACH_TYPE_xxx
value to the kernel. (see linux/arch/arm/tools/mach-types).


4. Setup the kernel tagged list
-------------------------------
4. Setup boot data
------------------

Existing boot loaders: OPTIONAL, HIGHLY RECOMMENDED
New boot loaders: MANDATORY

The boot loader must provide either a tagged list or a dtb image for
passing configuration data to the kernel. The physical address of the
boot data is passed to the kernel in register r2.

4a. Setup the kernel tagged list
--------------------------------

The boot loader must create and initialise the kernel tagged list.
A valid tagged list starts with ATAG_CORE and ends with ATAG_NONE.
The ATAG_CORE tag may or may not be empty. An empty ATAG_CORE tag
Expand Down Expand Up @@ -101,6 +107,24 @@ The tagged list must be placed in a region of memory where neither
the kernel decompressor nor initrd 'bootp' program will overwrite
it. The recommended placement is in the first 16KiB of RAM.

4b. Setup the device tree
-------------------------

The boot loader must load a device tree image (dtb) into system ram
at a 64bit aligned address and initialize it with the boot data. The
dtb format is documented in Documentation/devicetree/booting-without-of.txt.
The kernel will look for the dtb magic value of 0xd00dfeed at the dtb
physical address to determine if a dtb has been passed instead of a
tagged list.

The boot loader must pass at a minimum the size and location of the
system memory, and the root filesystem location. The dtb must be
placed in a region of memory where the kernel decompressor will not
overwrite it. The recommended placement is in the first 16KiB of RAM
with the caveat that it may not be located at physical address 0 since
the kernel interprets a value of 0 in r2 to mean neither a tagged list
nor a dtb were passed.

5. Calling the kernel image
---------------------------

Expand All @@ -125,7 +149,8 @@ In either case, the following conditions must be met:
- CPU register settings
r0 = 0,
r1 = machine type number discovered in (3) above.
r2 = physical address of tagged list in system RAM.
r2 = physical address of tagged list in system RAM, or
physical address of device tree block (dtb) in system RAM

- CPU mode
All forms of interrupts must be disabled (IRQs and FIQs)
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