From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f67.google.com ([209.85.160.67]:40550 "EHLO mail-pl0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751344AbeDEIQD (ORCPT ); Thu, 5 Apr 2018 04:16:03 -0400 Received: by mail-pl0-f67.google.com with SMTP id x4-v6so18081759pln.7 for ; Thu, 05 Apr 2018 01:16:03 -0700 (PDT) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin , Benjamin Herrenschmidt , Stewart Smith , linux-rtc@vger.kernel.org Subject: [PATCH 2/6] powerpc/powernv: OPAL RTC driver standardise OPAL_BUSY loops Date: Thu, 5 Apr 2018 18:15:43 +1000 Message-Id: <20180405081547.13266-3-npiggin@gmail.com> In-Reply-To: <20180405081547.13266-1-npiggin@gmail.com> References: <20180405081547.13266-1-npiggin@gmail.com> Sender: linux-rtc-owner@vger.kernel.org List-ID: Convert to using the standard delay poll/delay form. The OPAL RTC driver: - Did not previously delay or sleep in the OPAL_BUSY_EVENT case. There have been scheduling delays of up to 50 seconds observed here (BMC reboot can do it), which this should fix. Cc: linux-rtc@vger.kernel.org Signed-off-by: Nicholas Piggin --- arch/powerpc/platforms/powernv/opal-rtc.c | 6 ++++-- drivers/rtc/rtc-opal.c | 33 ++++++++++++++++++++----------- 2 files changed, 25 insertions(+), 14 deletions(-) diff --git a/arch/powerpc/platforms/powernv/opal-rtc.c b/arch/powerpc/platforms/powernv/opal-rtc.c index f8868864f373..f530cf62594d 100644 --- a/arch/powerpc/platforms/powernv/opal-rtc.c +++ b/arch/powerpc/platforms/powernv/opal-rtc.c @@ -48,10 +48,12 @@ unsigned long __init opal_get_boot_time(void) while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms); - if (rc == OPAL_BUSY_EVENT) + if (rc == OPAL_BUSY_EVENT) { + mdelay(OPAL_BUSY_DELAY_MS); opal_poll_events(NULL); - else if (rc == OPAL_BUSY) + } else if (rc == OPAL_BUSY) { mdelay(10); + } } if (rc != OPAL_SUCCESS) return 0; diff --git a/drivers/rtc/rtc-opal.c b/drivers/rtc/rtc-opal.c index 304e891e35fc..cddcc4749d39 100644 --- a/drivers/rtc/rtc-opal.c +++ b/drivers/rtc/rtc-opal.c @@ -57,7 +57,7 @@ static void tm_to_opal(struct rtc_time *tm, u32 *y_m_d, u64 *h_m_s_ms) static int opal_get_rtc_time(struct device *dev, struct rtc_time *tm) { - long rc = OPAL_BUSY; + s64 rc = OPAL_BUSY; int retries = 10; u32 y_m_d; u64 h_m_s_ms; @@ -66,13 +66,17 @@ static int opal_get_rtc_time(struct device *dev, struct rtc_time *tm) while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms); - if (rc == OPAL_BUSY_EVENT) + if (rc == OPAL_BUSY_EVENT) { + msleep(OPAL_BUSY_DELAY_MS); opal_poll_events(NULL); - else if (retries-- && (rc == OPAL_HARDWARE - || rc == OPAL_INTERNAL_ERROR)) + } else if (rc == OPAL_BUSY) { msleep(10); - else if (rc != OPAL_BUSY && rc != OPAL_BUSY_EVENT) - break; + } else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) { + if (retries--) { + msleep(10); /* Wait 10ms before retry */ + rc = OPAL_BUSY; /* go around again */ + } + } } if (rc != OPAL_SUCCESS) @@ -87,21 +91,26 @@ static int opal_get_rtc_time(struct device *dev, struct rtc_time *tm) static int opal_set_rtc_time(struct device *dev, struct rtc_time *tm) { - long rc = OPAL_BUSY; + s64 rc = OPAL_BUSY; int retries = 10; u32 y_m_d = 0; u64 h_m_s_ms = 0; tm_to_opal(tm, &y_m_d, &h_m_s_ms); + while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { rc = opal_rtc_write(y_m_d, h_m_s_ms); - if (rc == OPAL_BUSY_EVENT) + if (rc == OPAL_BUSY_EVENT) { + msleep(OPAL_BUSY_DELAY_MS); opal_poll_events(NULL); - else if (retries-- && (rc == OPAL_HARDWARE - || rc == OPAL_INTERNAL_ERROR)) + } else if (rc == OPAL_BUSY) { msleep(10); - else if (rc != OPAL_BUSY && rc != OPAL_BUSY_EVENT) - break; + } else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) { + if (retries--) { + msleep(10); /* Wait 10ms before retry */ + rc = OPAL_BUSY; /* go around again */ + } + } } return rc == OPAL_SUCCESS ? 0 : -EIO; -- 2.16.3