From: Nathan Lynch Date: Wed, 17 Nov 2021 06:02:59 +0000 (-0600) Subject: powerpc/rtas: rtas_busy_delay_time() kernel-doc X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=dd5cde457a5eb77088d1d9eecface47c0563cd43;p=linux.git 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: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211117060259.957178-3-nathanl@linux.ibm.com --- diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index 048599a68834c..733e6ef367589 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -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) {