path: root/arch/openrisc/lib
diff options
authorStefan Kristiansson <stefan.kristiansson@saunalahti.fi>2014-05-11 21:49:34 +0300
committerStafford Horne <shorne@gmail.com>2017-11-03 14:01:13 +0900
commit8e6d08e0a15e7d4d4b608b56597350d4cdd77710 (patch)
tree5c060395457f5bdd407c09b85caedcbbf701072c /arch/openrisc/lib
parent9b54470afd836278a7e6f0f08194e2e2dca4b6eb (diff)
openrisc: initial SMP support
This patch introduces the SMP support for the OpenRISC architecture. The SMP architecture requires cores which have multi-core features which have been introduced a few years back including: - New SPRS SPR_COREID SPR_NUMCORES - Shadow SPRs - Atomic Instructions - Cache Coherency - A wired in IPI controller This patch adds all of the SMP specific changes to core infrastructure, it looks big but it needs to go all together as its hard to split this one up. Boot loader spinning of second cpu is not supported yet, it's assumed that Linux is booted straight after cpu reset. The bulk of these changes are trivial changes to refactor to use per cpu data structures throughout. The addition of the smp.c and changes in time.c are the changes. Some specific notes: MM changes ---------- The reason why this is created as an array, and not with DEFINE_PER_CPU is that doing it this way, we'll save a load in the tlb-miss handler (the load from __per_cpu_offset). TLB Flush --------- The SMP implementation of flush_tlb_* works by sending out a function-call IPI to all the non-local cpus by using the generic on_each_cpu() function. Currently, all flush_tlb_* functions will result in a flush_tlb_all(), which has always been the behaviour in the UP case. CPU INFO -------- This creates a per cpu cpuinfo struct and fills it out accordingly for each activated cpu. show_cpuinfo is also updated to reflect new version information in later versions of the spec. SMP API ------- This imitates the arm64 implementation by having a smp_cross_call callback that can be set by set_smp_cross_call to initiate an IPI and a handle_IPI function that is expected to be called from an IPI irqchip driver. Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> [shorne@gmail.com: added cpu stop, checkpatch fixes, wrote commit message] Signed-off-by: Stafford Horne <shorne@gmail.com>
Diffstat (limited to 'arch/openrisc/lib')
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/openrisc/lib/delay.c b/arch/openrisc/lib/delay.c
index 8b13fdf43ec6..a92bd621aa1f 100644
--- a/arch/openrisc/lib/delay.c
+++ b/arch/openrisc/lib/delay.c
@@ -25,7 +25,7 @@
int read_current_timer(unsigned long *timer_value)
- *timer_value = mfspr(SPR_TTCR);
+ *timer_value = get_cycles();
return 0;

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