Commit dd5cde45 authored by Nathan Lynch's avatar Nathan Lynch Committed by Michael Ellerman
Browse files

powerpc/rtas: rtas_busy_delay_time() kernel-doc 



Provide API documentation for rtas_busy_delay_time(), explaining why we
return the same value for 9900 and -2.

Signed-off-by: default avatarNathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211117060259.957178-3-nathanl@linux.ibm.com
parent 38f7b706

arch/powerpc/kernel/rtas.c

+19 −2
Original line number Diff line number Diff line
@@ -492,8 +492,25 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...) 
}

EXPORT_SYMBOL(rtas_call);



/* For RTAS_BUSY (-2), delay for 1 millisecond.  For an extended busy status

 * code of 990n, perform the hinted delay of 10^n (last digit) milliseconds.

/**

 * rtas_busy_delay_time() - From an RTAS status value, calculate the

 *                          suggested delay time in milliseconds.

 *

 * @status: a value returned from rtas_call() or similar APIs which return

 *          the status of a RTAS function call.

 *

 * Context: Any context.

 *

 * Return:

 * * 100000 - If @status is 9905.

 * * 10000  - If @status is 9904.

 * * 1000   - If @status is 9903.

 * * 100    - If @status is 9902.

 * * 10     - If @status is 9901.

 * * 1      - If @status is either 9900 or -2. This is "wrong" for -2, but

 *            some callers depend on this behavior, and the worst outcome

 *            is that they will delay for longer than necessary.

 * * 0      - If @status is not a busy or extended delay value.

 */

unsigned int rtas_busy_delay_time(int status)

{