Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753720AbdDMGgZ convert rfc822-to-8bit (ORCPT ); Thu, 13 Apr 2017 02:36:25 -0400 Received: from ozlabs.org ([103.22.144.67]:48029 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751300AbdDMGgW (ORCPT ); Thu, 13 Apr 2017 02:36:22 -0400 Message-ID: <1492065380.4624.50.camel@neuling.org> Subject: Re: [PATCH 1/3] powernv:idle: Use correct IDLE_THREAD_BITS in POWER8/9 From: Michael Neuling To: "Gautham R. Shenoy" , Michael Ellerman , Benjamin Herrenschmidt , "Shreyas B. Prabhu" , Shilpasri G Bhat , Vaidyanathan Srinivasan , Anton Blanchard , Balbir Singh , Akshay Adiga , Nicholas Piggin , Mahesh J Salgaonkar , "Aneesh Kumar K.V" Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Date: Thu, 13 Apr 2017 16:36:20 +1000 In-Reply-To: <1b89d07b1a7ea140501a86b1ed246c5af1b0ce83.1491996797.git.ego@linux.vnet.ibm.com> References: <1b89d07b1a7ea140501a86b1ed246c5af1b0ce83.1491996797.git.ego@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.22.3-0ubuntu0.1 Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2976 Lines: 82 On Wed, 2017-04-12 at 17:16 +0530, Gautham R. Shenoy wrote: > From: "Gautham R. Shenoy" > > This patch ensures that POWER8 and POWER9 processors use the correct > value of IDLE_THREAD_BITS as POWER8 has 8 threads per core and hence > the IDLE_THREAD_BITS should be 0xFF while POWER9 has only 4 threads > per core and hence the IDLE_THREAD_BITS should be 0xF. Why don't we derive this from the device tree rather than hard wiring it per cpu type? Mikey > > Signed-off-by: Gautham R. Shenoy > --- >  arch/powerpc/include/asm/cpuidle.h    | 3 ++- >  arch/powerpc/kernel/idle_book3s.S     | 9 ++++++--- >  arch/powerpc/platforms/powernv/idle.c | 5 ++++- >  3 files changed, 12 insertions(+), 5 deletions(-) > > diff --git a/arch/powerpc/include/asm/cpuidle.h > b/arch/powerpc/include/asm/cpuidle.h > index 52586f9..fece6ca 100644 > --- a/arch/powerpc/include/asm/cpuidle.h > +++ b/arch/powerpc/include/asm/cpuidle.h > @@ -34,7 +34,8 @@ >  #define PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT 8 >  #define PNV_CORE_IDLE_THREAD_WINKLE_BITS 0x0000FF00 >   > -#define PNV_CORE_IDLE_THREAD_BITS        0x000000FF > +#define PNV_CORE_IDLE_4THREAD_BITS        0x0000000F > +#define PNV_CORE_IDLE_8THREAD_BITS        0x000000FF >   >  /* >   * ============================ NOTE ================================= > diff --git a/arch/powerpc/kernel/idle_book3s.S > b/arch/powerpc/kernel/idle_book3s.S > index 2b13fe2..9b747e9 100644 > --- a/arch/powerpc/kernel/idle_book3s.S > +++ b/arch/powerpc/kernel/idle_book3s.S > @@ -223,7 +223,7 @@ lwarx_loop1: >   add r15,r15,r5 /* Add if winkle */ >   andc r15,r15,r7 /* Clear thread bit */ >   > - andi. r9,r15,PNV_CORE_IDLE_THREAD_BITS > + andi. r9,r15,PNV_CORE_IDLE_8THREAD_BITS >   >  /* >   * If cr0 = 0, then current thread is the last thread of the core entering > @@ -582,8 +582,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) >   stwcx. r15,0,r14 >   bne- 1b >   isync > - > - andi. r9,r15,PNV_CORE_IDLE_THREAD_BITS > +BEGIN_FTR_SECTION > + andi. r9,r15,PNV_CORE_IDLE_4THREAD_BITS > +FTR_SECTION_ELSE > + andi. r9,r15,PNV_CORE_IDLE_8THREAD_BITS > +ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300) >   cmpwi cr2,r9,0 >   >   /* > diff --git a/arch/powerpc/platforms/powernv/idle.c > b/arch/powerpc/platforms/powernv/idle.c > index 445f30a..d46920b 100644 > --- a/arch/powerpc/platforms/powernv/idle.c > +++ b/arch/powerpc/platforms/powernv/idle.c > @@ -112,7 +112,10 @@ static void pnv_alloc_idle_core_states(void) >   size_t paca_ptr_array_size; >   >   core_idle_state = kmalloc_node(sizeof(u32), GFP_KERNEL, > node); > - *core_idle_state = PNV_CORE_IDLE_THREAD_BITS; > + if (cpu_has_feature(CPU_FTR_ARCH_300)) > + *core_idle_state = PNV_CORE_IDLE_4THREAD_BITS; > + else > + *core_idle_state = PNV_CORE_IDLE_8THREAD_BITS; >   paca_ptr_array_size = (threads_per_core * >          sizeof(struct paca_struct *)); >