From patchwork Sun Jan 1 20:15:19 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: 710070 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 3tsBKL2wvdz9sCG for ; Mon, 2 Jan 2017 07:15:34 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932431AbdAAUPd (ORCPT ); Sun, 1 Jan 2017 15:15:33 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47638 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932229AbdAAUPd (ORCPT ); Sun, 1 Jan 2017 15:15:33 -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 AA04581239; Sun, 1 Jan 2017 20:15:33 +0000 (UTC) Received: from shalem.localdomain.com (vpn1-7-169.ams2.redhat.com [10.36.7.169]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v01KFMJ9027103; Sun, 1 Jan 2017 15:15:31 -0500 From: Hans de Goede To: Jarkko Nikula , Wolfram Sang , Len Brown , Andy Shevchenko Cc: Mika Westerberg , Jani Nikula , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Takashi Iwai , "russianneuromancer @ ya . ru" , linux-i2c@vger.kernel.org, intel-gfx , Hans de Goede Subject: [PATCH v5 4/6] i2c: designware-baytrail: Disallow the CPU to enter C6 or C7 while holding the punit semaphore Date: Sun, 1 Jan 2017 21:15:19 +0100 Message-Id: <20170101201521.12364-4-hdegoede@redhat.com> In-Reply-To: <20170101201521.12364-1-hdegoede@redhat.com> References: <20170101201521.12364-1-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 [10.5.110.25]); Sun, 01 Jan 2017 20:15:33 +0000 (UTC) Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On my cherrytrail tablet with axp288 pmic, just doing a bunch of repeated reads from the pmic, e.g. "i2cdump -y 14 0x34" would lookup the tablet in 1 - 3 runs guaranteed. This seems to be causes by the cpu trying to enter C6 or C7 while we hold the punit bus semaphore, at which point everything just hangs. Avoid this by disallowing the CPU to enter C6 or C7 before acquiring the punit bus semaphore. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=109051 Signed-off-by: Hans de Goede Tested-by: Takashi Iwai Reviewed-by: Andy Shevchenko Acked-by: Jarkko Nikula --- Changes in v2: -New patch in v2 of this set Changes in v3: -Change commit message and comment in the code from "force the CPU to C1" to "Disallow the CPU to enter C6 or C7", as the CPU may still be in either C0 or C1 with the request pm_qos Changes in v4: -Rename i2c_dw_eval_lock_support to i2c_dw_probe_lock_support so that we can add a matching i2c_dw_remove_lock_support cleanup function -Move qm_pos removal to new i2c_dw_remove_lock_support function -Move pm_qos_add_request to the end of i2c_dw_probe_lock_support Changes in v5: -Update the pm_qos for a latency of 0 *before* requesting the semaphore, instead of doing it while waiting for the request to be acked --- drivers/i2c/busses/i2c-designware-baytrail.c | 24 ++++++++++++++++++++++-- drivers/i2c/busses/i2c-designware-core.h | 9 +++++++-- drivers/i2c/busses/i2c-designware-platdrv.c | 4 +++- 3 files changed, 32 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c index cf02222..650a700 100644 --- a/drivers/i2c/busses/i2c-designware-baytrail.c +++ b/drivers/i2c/busses/i2c-designware-baytrail.c @@ -16,6 +16,7 @@ #include #include #include +#include #include @@ -56,6 +57,8 @@ static void reset_semaphore(struct dw_i2c_dev *dev) data &= ~PUNIT_SEMAPHORE_BIT; if (iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, PUNIT_SEMAPHORE, data)) dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n"); + + pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE); } static int baytrail_i2c_acquire(struct dw_i2c_dev *dev) @@ -72,11 +75,18 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev) if (!dev->release_lock) return 0; + /* + * Disallow the CPU to enter C6 or C7 state, entering these states + * requires the punit to talk to the pmic and if this happens while + * we're holding the semaphore, the SoC hangs. + */ + pm_qos_update_request(&dev->pm_qos, 0); + /* host driver writes to side band semaphore register */ ret = iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, PUNIT_SEMAPHORE, sem); if (ret) { dev_err(dev->dev, "iosf punit semaphore request failed\n"); - return ret; + goto out; } /* host driver waits for bit 0 to be set in semaphore register */ @@ -95,6 +105,7 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev) } while (time_before(jiffies, end)); dev_err(dev->dev, "punit semaphore timed out, resetting\n"); +out: reset_semaphore(dev); ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE, &sem); @@ -121,7 +132,7 @@ static void baytrail_i2c_release(struct dw_i2c_dev *dev) jiffies_to_msecs(jiffies - acquired)); } -int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev) +int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev) { acpi_status status; unsigned long long shared_host = 0; @@ -149,5 +160,14 @@ int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev) dev->release_lock = baytrail_i2c_release; dev->pm_runtime_disabled = true; + pm_qos_add_request(&dev->pm_qos, PM_QOS_CPU_DMA_LATENCY, + PM_QOS_DEFAULT_VALUE); + return 0; } + +void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev) +{ + if (dev->acquire_lock) + pm_qos_remove_request(&dev->pm_qos); +} diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index fb143f5..871970e 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -22,6 +22,7 @@ * */ +#include #define DW_IC_CON_MASTER 0x1 #define DW_IC_CON_SPEED_STD 0x2 @@ -67,6 +68,7 @@ * @fp_lcnt: fast plus LCNT value * @hs_hcnt: high speed HCNT value * @hs_lcnt: high speed LCNT value + * @pm_qos: pm_qos_request used while holding a hardware lock on the bus * @acquire_lock: function to acquire a hardware lock on the bus * @release_lock: function to release a hardware lock on the bus * @pm_runtime_disabled: true if pm runtime is disabled @@ -114,6 +116,7 @@ struct dw_i2c_dev { u16 fp_lcnt; u16 hs_hcnt; u16 hs_lcnt; + struct pm_qos_request pm_qos; int (*acquire_lock)(struct dw_i2c_dev *dev); void (*release_lock)(struct dw_i2c_dev *dev); bool pm_runtime_disabled; @@ -131,7 +134,9 @@ extern u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev); extern int i2c_dw_probe(struct dw_i2c_dev *dev); #if IS_ENABLED(CONFIG_I2C_DESIGNWARE_BAYTRAIL) -extern int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev); +extern int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev); +extern void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev); #else -static inline int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev) { return 0; } +static inline int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev) { return 0; } +static inline void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev) {} #endif diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index 97a2ca1..b0a64a2 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -210,7 +210,7 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) return -EINVAL; } - r = i2c_dw_eval_lock_support(dev); + r = i2c_dw_probe_lock_support(dev); if (r) return r; @@ -291,6 +291,8 @@ static int dw_i2c_plat_remove(struct platform_device *pdev) if (!dev->pm_runtime_disabled) pm_runtime_disable(&pdev->dev); + i2c_dw_remove_lock_support(dev); + return 0; }