Commit 6ff8f59f authored by Ben Dooks's avatar Ben Dooks Committed by Russell King

[ARM] 3076/1: S3C2410 - updated documentation for platfrom data init

Patch from Ben Dooks

Update the Documentation/arm/Samsung-S3C24XX to add
example platform data initialisation, and add the
linux-arm mailing list URL.
Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent e838ffc2
......@@ -81,7 +81,8 @@ Adding New Machines
Any large scale modifications, or new drivers should be discussed
on the ARM kernel mailing list (linux-arm-kernel) before being
attempted.
attempted. See http://www.arm.linux.org.uk/mailinglists/ for the
mailing list information.
NAND
......@@ -120,6 +121,43 @@ Clock Management
various clock units
Platform Data
-------------
Whenever a device has platform specific data that is specified
on a per-machine basis, care should be taken to ensure the
following:
1) that default data is not left in the device to confuse the
driver if a machine does not set it at startup
2) the data should (if possible) be marked as __initdata,
to ensure that the data is thrown away if the machine is
not the one currently in use.
The best way of doing this is to make a function that
kmalloc()s an area of memory, and copies the __initdata
and then sets the relevant device's platform data. Making
the function `__init` takes care of ensuring it is discarded
with the rest of the initialisation code
static __init void s3c24xx_xxx_set_platdata(struct xxx_data *pd)
{
struct s3c2410_xxx_mach_info *npd;
npd = kmalloc(sizeof(struct s3c2410_xxx_mach_info), GFP_KERNEL);
if (npd) {
memcpy(npd, pd, sizeof(struct s3c2410_xxx_mach_info));
s3c_device_xxx.dev.platform_data = npd;
} else {
printk(KERN_ERR "no memory for xxx platform data\n");
}
}
Note, since the code is marked as __init, it should not be
exported outside arch/arm/mach-s3c2410/, or exported to
modules via EXPORT_SYMBOL() and related functions.
Port Contributors
-----------------
......@@ -149,6 +187,7 @@ Document Changes
06 Mar 2005 - BJD - Added Christer Weinigel
08 Mar 2005 - BJD - Added LCVR to list of people, updated introduction
08 Mar 2005 - BJD - Added section on adding machines
09 Sep 2005 - BJD - Added section on platform data
Document Author
---------------
......
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