From 87a70bcdb41008decfcf7c217e26b0bcd7f52642 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Wed, 3 Feb 2016 03:15:32 +0000 Subject: [PATCH] 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 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 --- arch/mips/kernel/cps-vec.S | 39 ++++++++++++++++++++++++--------------- 1 file changed, 24 insertions(+), 15 deletions(-) diff --git a/arch/mips/kernel/cps-vec.S b/arch/mips/kernel/cps-vec.S index 2613de9..4849cbd 100644 --- a/arch/mips/kernel/cps-vec.S +++ b/arch/mips/kernel/cps-vec.S @@ -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 -- 2.7.4