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-rw-r--r--Documentation/arm/Samsung-S3C24XX/Overview.txt41
1 files changed, 40 insertions, 1 deletions
diff --git a/Documentation/arm/Samsung-S3C24XX/Overview.txt b/Documentation/arm/Samsung-S3C24XX/Overview.txt
index 3af4d29..89aa89d 100644
--- a/Documentation/arm/Samsung-S3C24XX/Overview.txt
+++ b/Documentation/arm/Samsung-S3C24XX/Overview.txt
@@ -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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