From patchwork Fri Feb 10 10:27:51 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 726474 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3vKWPG05lQz9rxw for ; Fri, 10 Feb 2017 21:28:18 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751644AbdBJK2Q (ORCPT ); Fri, 10 Feb 2017 05:28:16 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44068 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751233AbdBJK2P (ORCPT ); Fri, 10 Feb 2017 05:28:15 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9D3F06AAE9; Fri, 10 Feb 2017 10:28:10 +0000 (UTC) Received: from shalem.localdomain.com (ovpn-117-212.ams2.redhat.com [10.36.117.212]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v1AAS4j9005761; Fri, 10 Feb 2017 05:28:07 -0500 From: Hans de Goede To: Daniel Vetter , Jani Nikula , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Jarkko Nikula , Wolfram Sang , Len Brown , Andy Shevchenko , Thomas Gleixner , "H . Peter Anvin" Cc: Hans de Goede , intel-gfx , dri-devel@lists.freedesktop.org, Mika Westerberg , Takashi Iwai , "russianneuromancer @ ya . ru" , linux-i2c@vger.kernel.org Subject: [PATCH v3 01/12] x86/platform/intel/iosf_mbi: Add a mutex for P-Unit access Date: Fri, 10 Feb 2017 11:27:51 +0100 Message-Id: <20170210102802.20898-2-hdegoede@redhat.com> In-Reply-To: <20170210102802.20898-1-hdegoede@redhat.com> References: <20170210102802.20898-1-hdegoede@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 10 Feb 2017 10:28:10 +0000 (UTC) Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org One some systems the P-Unit accesses the PMIC to change various voltages through the same bus as other kernel drivers use for e.g. battery monitoring. If a driver sends requests to the P-Unit which require the P-Unit to access the PMIC bus while another driver is also accessing the PMIC bus various bad things happen. This commit adds a mutex to protect the P-Unit against simultaneous accesses and 2 functions to lock / unlock this mutex. Note on these systems the i2c-bus driver will request a sempahore from the P-Unit for exclusive access to the PMIC bus when i2c drivers are accessing it, but this does not appear to be sufficient, we still need to avoid making certain P-Unit requests during the access window to avoid problems. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241 Signed-off-by: Hans de Goede Tested-by: tagorereddy Reviewed-by: Andy Shevchenko --- Changes in v2: -Rename iosf_mbi_punit_lock/_unlock to _acquire/_release rename -Spelling: P-Unit, PMIC --- arch/x86/include/asm/iosf_mbi.h | 31 +++++++++++++++++++++++++++++++ arch/x86/platform/intel/iosf_mbi.c | 13 +++++++++++++ 2 files changed, 44 insertions(+) diff --git a/arch/x86/include/asm/iosf_mbi.h b/arch/x86/include/asm/iosf_mbi.h index b41ee16..f6119d0 100644 --- a/arch/x86/include/asm/iosf_mbi.h +++ b/arch/x86/include/asm/iosf_mbi.h @@ -88,6 +88,33 @@ int iosf_mbi_write(u8 port, u8 opcode, u32 offset, u32 mdr); */ int iosf_mbi_modify(u8 port, u8 opcode, u32 offset, u32 mdr, u32 mask); +/** + * iosf_mbi_punit_acquire() - Acquire access to the P-Unit + * + * One some systems the P-Unit accesses the PMIC to change various voltages + * through the same bus as other kernel drivers use for e.g. battery monitoring. + * + * If a driver sends requests to the P-Unit which require the P-Unit to access + * the PMIC bus while another driver is also accessing the PMIC bus various bad + * things happen. + * + * To avoid these problems this function must be called before accessing the + * P-Unit or the PMIC, be it through iosf_mbi* functions or through other means. + * + * Note on these systems the i2c-bus driver will request a sempahore from the + * P-Unit for exclusive access to the PMIC bus when i2c drivers are accessing + * it, but this does not appear to be sufficient, we still need to avoid making + * certain P-Unit requests during the access window to avoid problems. + * + * This function locks a mutex, as such it may sleep. + */ +void iosf_mbi_punit_acquire(void); + +/** + * iosf_mbi_punit_release() - Release access to the P-Unit + */ +void iosf_mbi_punit_release(void); + #else /* CONFIG_IOSF_MBI is not enabled */ static inline bool iosf_mbi_available(void) @@ -115,6 +142,10 @@ int iosf_mbi_modify(u8 port, u8 opcode, u32 offset, u32 mdr, u32 mask) WARN(1, "IOSF_MBI driver not available"); return -EPERM; } + +static inline void iosf_mbi_punit_acquire(void) {} +static inline void iosf_mbi_punit_release(void) {} + #endif /* CONFIG_IOSF_MBI */ #endif /* IOSF_MBI_SYMS_H */ diff --git a/arch/x86/platform/intel/iosf_mbi.c b/arch/x86/platform/intel/iosf_mbi.c index edf2c54..ed24fa9f 100644 --- a/arch/x86/platform/intel/iosf_mbi.c +++ b/arch/x86/platform/intel/iosf_mbi.c @@ -34,6 +34,7 @@ static struct pci_dev *mbi_pdev; static DEFINE_SPINLOCK(iosf_mbi_lock); +static DEFINE_MUTEX(iosf_mbi_punit_mutex); static inline u32 iosf_mbi_form_mcr(u8 op, u8 port, u8 offset) { @@ -190,6 +191,18 @@ bool iosf_mbi_available(void) } EXPORT_SYMBOL(iosf_mbi_available); +void iosf_mbi_punit_acquire(void) +{ + mutex_lock(&iosf_mbi_punit_mutex); +} +EXPORT_SYMBOL(iosf_mbi_punit_acquire); + +void iosf_mbi_punit_release(void) +{ + mutex_unlock(&iosf_mbi_punit_mutex); +} +EXPORT_SYMBOL(iosf_mbi_punit_release); + #ifdef CONFIG_IOSF_MBI_DEBUG static u32 dbg_mdr; static u32 dbg_mcr;