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MIPS: smp-cps: Skip core setup if coherent 

In preparation for supporting MIPSr6 multithreading (ie. VPs) which will
begin execution from the core reset vector, skip core level setup if the
core is already coherent. This is never the case when a core is first
started, since boot_core explicitly clears the cores GCR_Cx_COH_EN
register, and always the case when secondary VPs start since the first
VP to start will have enabled coherence after initialising the core &
its caches.

One notable side effect of this patch is that eva_init gets called
slightly earlier, prior to mips_cps_core_init rather than after it.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12338/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2016-02-03 03:15:32 +00:00 committed by Ralf Baechle
parent f12401d721
commit 87a70bcdb4
1 changed files with 24 additions and 15 deletions
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39
arch/mips/kernel/cps-vec.S
View File

@ -101,43 +101,52 @@ not_nmi:
li t0, ST0_CU1 | ST0_CU0 | ST0_BEV | STATUS_BITDEPS
mtc0 t0, CP0_STATUS
/* Skip cache & coherence setup if we're already coherent */
cmgcrb v1
lw s7, GCR_CL_COHERENCE_OFS(v1)
bnez s7, 1f
nop
/* Initialize the L1 caches */
jal mips_cps_cache_init
nop
/* Enter the coherent domain */
li t0, 0xff
sw t0, GCR_CL_COHERENCE_OFS(v1)
ehb
/* Set Kseg0 CCA to that in s0 */
mfc0 t0, CP0_CONFIG
1: mfc0 t0, CP0_CONFIG
ori t0, 0x7
xori t0, 0x7
or t0, t0, s0
mtc0 t0, CP0_CONFIG
ehb
/* Enter the coherent domain */
cmgcrb v1
li t0, 0xff
sw t0, GCR_CL_COHERENCE_OFS(v1)
ehb
/* Jump to kseg0 */
PTR_LA t0, 1f
jr t0
nop
/*
* We're up, cached & coherent. Perform any further required core-level
* initialisation.
* We're up, cached & coherent. Perform any EVA initialization necessary
* before we access memory.
*/
1: jal mips_cps_core_init
nop
/* Do any EVA initialization if necessary */
eva_init
1: eva_init
/* Retrieve boot configuration pointers */
jal mips_cps_get_bootcfg
nop
/* Skip core-level init if we started up coherent */
bnez s7, 1f
nop
/* Perform any further required core-level initialisation */
jal mips_cps_core_init
nop
/*
* Boot any other VPEs within this core that should be online, and
* deactivate this VPE if it should be offline.
@ -147,7 +156,7 @@ not_nmi:
move a0, v0
/* Off we go! */
PTR_L t1, VPEBOOTCFG_PC(v1)
1: PTR_L t1, VPEBOOTCFG_PC(v1)
PTR_L gp, VPEBOOTCFG_GP(v1)
PTR_L sp, VPEBOOTCFG_SP(v1)
jr t1