Author: ian
Date: Sat Sep 2 19:20:11 2017
New Revision: 323132
URL: https://svnweb.freebsd.org/changeset/base/323132
Log:
The latest RPi firmware leaves secondary cores in a wait-for-event (WFE)
state to save power, so after writing the entry point address for a core to
the mailbox, use a dsb() to synchronize the execution pipeline to the data
written, then use an sev() to wake up the core.
Submitted by: Sylvain Garrigues <syl...@gmail.com>
Modified:
head/sys/arm/broadcom/bcm2835/bcm2836_mp.c
Modified: head/sys/arm/broadcom/bcm2835/bcm2836_mp.c
==============================================================================
--- head/sys/arm/broadcom/bcm2835/bcm2836_mp.c Sat Sep 2 18:18:49 2017
(r323131)
+++ head/sys/arm/broadcom/bcm2835/bcm2836_mp.c Sat Sep 2 19:20:11 2017
(r323132)
@@ -117,7 +117,9 @@ bcm2836_mp_start_ap(platform_t plat)
/* set entry point to mailbox 3 */
BSWR4(MBOX3SET_CORE(i),
(uint32_t)pmap_kextract((vm_offset_t)mpentry));
- wmb();
+ /* Firmware put cores in WFE state, need SEV to wake up. */
+ dsb();
+ sev();
/* wait for bootup */
retry = 1000;
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