From 4409a5eef6d1d669caad1bfe3fbefee87ea7734e Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Mon, 6 May 2013 12:20:52 -0500 Subject: coreboot: add thread cooperative multitasking The cooperative multitasking support allows the boot state machine to be ran cooperatively with other threads of work. The main thread still continues to run the boot state machine (src/lib/hardwaremain.c). All callbacks from the state machine are still ran synchronously from within the main thread's context. Without any other code added the only change to the boot sequence when cooperative multitasking is enabled is the queueing of an idlle thread. The idle thread is responsible for ensuring progress is made by calling timer callbacks. The main thread can yield to any other threads in the system. That means that anyone that spins up a thread must ensure no shared resources are used from 2 or more execution contexts. The support is originally intentioned to allow for long work itesm with busy loops to occur in parallel during a boot. Note that the intention on when to yield a thread will be on calls to udelay(). Change-Id: Ia4d67a38665b12ce2643474843a93babd8a40c77 Signed-off-by: Aaron Durbin Reviewed-on: http://review.coreboot.org/3206 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich --- src/Kconfig | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'src/Kconfig') diff --git a/src/Kconfig b/src/Kconfig index ce5a048bcc..4366bc809b 100644 --- a/src/Kconfig +++ b/src/Kconfig @@ -324,6 +324,22 @@ config TIMER_QUEUE help Provide a timer queue for performing time-based callbacks. +config COOP_MULTITASKING + def_bool n + depends on TIMER_QUEUE + help + Cooperative multitasking allows callbacks to be multiplexed on the + main thread of ramstage. With this enabled it allows for multiple + execution paths to take place when they have udelay() calls within + their code. + +config NUM_THREADS + int + default 4 + depends on COOP_MULTITASKING + help + How many execution threads to cooperatively multitask with. + config HIGH_SCRATCH_MEMORY_SIZE hex default 0x0 -- cgit v1.2.3