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-rw-r--r--Documentation/arm/Samsung-S3C24XX/Suspend.txt35
1 files changed, 33 insertions, 2 deletions
diff --git a/Documentation/arm/Samsung-S3C24XX/Suspend.txt b/Documentation/arm/Samsung-S3C24XX/Suspend.txt
index e12bc3284a27..0dab6e32c130 100644
--- a/Documentation/arm/Samsung-S3C24XX/Suspend.txt
+++ b/Documentation/arm/Samsung-S3C24XX/Suspend.txt
@@ -5,10 +5,10 @@
Introduction
------------
- The S3C2410 supports a low-power suspend mode, where the SDRAM is kept
+ The S3C24XX supports a low-power suspend mode, where the SDRAM is kept
in Self-Refresh mode, and all but the essential peripheral blocks are
powered down. For more information on how this works, please look
- at the S3C2410 datasheets from Samsung.
+ at the relevant CPU datasheet from Samsung.
Requirements
@@ -56,6 +56,27 @@ Machine Support
Note, the original method of adding an late_initcall() is wrong,
and will end up initialising all compiled machines' pm init!
+ The following is an example of code used for testing wakeup from
+ an falling edge on IRQ_EINT0:
+
+
+static irqreturn_t button_irq(int irq, void *pw)
+{
+ return IRQ_HANDLED;
+}
+
+statuc void __init machine_init(void)
+{
+ ...
+
+ request_irq(IRQ_EINT0, button_irq, IRQF_TRIGGER_FALLING,
+ "button-irq-eint0", NULL);
+
+ enable_irq_wake(IRQ_EINT0);
+
+ s3c2410_pm_init();
+}
+
Debugging
---------
@@ -70,6 +91,12 @@ Debugging
care should be taken that any external clock sources that the UARTs
rely on are still enabled at that point.
+ 3) If any debugging is placed in the resume path, then it must have the
+ relevant clocks and peripherals setup before use (ie, bootloader).
+
+ For example, if you transmit a character from the UART, the baud
+ rate and uart controls must be setup beforehand.
+
Configuration
-------------
@@ -89,6 +116,10 @@ Configuration
Allows the entire memory to be checksummed before and after the
suspend to see if there has been any corruption of the contents.
+ Note, the time to calculate the CRC is dependant on the CPU speed
+ and the size of memory. For an 64Mbyte RAM area on an 200MHz
+ S3C2410, this can take approximately 4 seconds to complete.
+
This support requires the CRC32 function to be enabled.
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