diff options
Diffstat (limited to 'Documentation/arm')
| -rw-r--r-- | Documentation/arm/Samsung-S3C24XX/Suspend.txt | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/Documentation/arm/Samsung-S3C24XX/Suspend.txt b/Documentation/arm/Samsung-S3C24XX/Suspend.txt index e12bc3284a2..0dab6e32c13 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. |