From 929d4f51e6b87900c9179eb62d6b43db6ce4930d Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Wed, 7 Sep 2016 10:45:17 +0100 Subject: [PATCH] MIPS: pm-cps: Add MIPSr6 CPU support This patch adds support for CPUs implementing the MIPSr6 ISA to the CPS power management code. Three changes are necessary: 1. In MIPSr6, coupled coherence is necessary when CPUS implement multiple Virtual Processors (VPs). 2. MIPSr6 virtual processors are more like real cores and cannot yield to other VPs on the same core, so drop the MT ASE yield instruction. 3. To halt a MIPSr6 VP, the CPC VP_STOP register is used rather than the MT ASE TCHalt CP0 register. Signed-off-by: Matt Redfearn Reviewed-by: Paul Burton Cc: Adam Buchbinder Cc: Masahiro Yamada Cc: Kees Cook Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14225/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/pm-cps.h | 6 ++++-- arch/mips/kernel/pm-cps.c | 22 ++++++++++++++++++---- 2 files changed, 22 insertions(+), 6 deletions(-) diff --git a/arch/mips/include/asm/pm-cps.h b/arch/mips/include/asm/pm-cps.h index 625eda53d571..89d58d80b77b 100644 --- a/arch/mips/include/asm/pm-cps.h +++ b/arch/mips/include/asm/pm-cps.h @@ -13,10 +13,12 @@ /* * The CM & CPC can only handle coherence & power control on a per-core basis, - * thus in an MT system the VPEs within each core are coupled and can only + * thus in an MT system the VP(E)s within each core are coupled and can only * enter or exit states requiring CM or CPC assistance in unison. */ -#ifdef CONFIG_MIPS_MT +#if defined(CONFIG_CPU_MIPSR6) +# define coupled_coherence cpu_has_vp +#elif defined(CONFIG_MIPS_MT) # define coupled_coherence cpu_has_mipsmt #else # define coupled_coherence 0 diff --git a/arch/mips/kernel/pm-cps.c b/arch/mips/kernel/pm-cps.c index b3a7d36ada5a..440e79259566 100644 --- a/arch/mips/kernel/pm-cps.c +++ b/arch/mips/kernel/pm-cps.c @@ -129,7 +129,7 @@ int cps_pm_enter_state(enum cps_pm_state state) return -EINVAL; /* Calculate which coupled CPUs (VPEs) are online */ -#ifdef CONFIG_MIPS_MT +#if defined(CONFIG_MIPS_MT) || defined(CONFIG_CPU_MIPSR6) if (cpu_online(cpu)) { cpumask_and(coupled_mask, cpu_online_mask, &cpu_sibling_map[cpu]); @@ -431,7 +431,8 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum cps_pm_state state) uasm_i_lw(&p, t0, 0, r_nc_count); uasm_il_bltz(&p, &r, t0, lbl_secondary_cont); uasm_i_ehb(&p); - uasm_i_yield(&p, zero, t1); + if (cpu_has_mipsmt) + uasm_i_yield(&p, zero, t1); uasm_il_b(&p, &r, lbl_poll_cont); uasm_i_nop(&p); } else { @@ -439,8 +440,21 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum cps_pm_state state) * The core will lose power & this VPE will not continue * so it can simply halt here. */ - uasm_i_addiu(&p, t0, zero, TCHALT_H); - uasm_i_mtc0(&p, t0, 2, 4); + if (cpu_has_mipsmt) { + /* Halt the VPE via C0 tchalt register */ + uasm_i_addiu(&p, t0, zero, TCHALT_H); + uasm_i_mtc0(&p, t0, 2, 4); + } else if (cpu_has_vp) { + /* Halt the VP via the CPC VP_STOP register */ + unsigned int vpe_id; + + vpe_id = cpu_vpe_id(&cpu_data[cpu]); + uasm_i_addiu(&p, t0, zero, 1 << vpe_id); + UASM_i_LA(&p, t1, (long)addr_cpc_cl_vp_stop()); + uasm_i_sw(&p, t0, 0, t1); + } else { + BUG(); + } uasm_build_label(&l, p, lbl_secondary_hang); uasm_il_b(&p, &r, lbl_secondary_hang); uasm_i_nop(&p); -- 2.20.1