From patchwork Fri Feb 5 05:42:30 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Vutla X-Patchwork-Id: 8231751 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id EC312BEEE5 for ; Fri, 5 Feb 2016 05:46:30 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0F28B20397 for ; Fri, 5 Feb 2016 05:46:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81234203A0 for ; Fri, 5 Feb 2016 05:46:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751353AbcBEFq1 (ORCPT ); Fri, 5 Feb 2016 00:46:27 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:45504 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750841AbcBEFq0 (ORCPT ); Fri, 5 Feb 2016 00:46:26 -0500 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id u155k1xp025326; Thu, 4 Feb 2016 23:46:01 -0600 Received: from DLEE70.ent.ti.com (dlemailx.itg.ti.com [157.170.170.113]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id u155k1UE030830; Thu, 4 Feb 2016 23:46:01 -0600 Received: from dlep33.itg.ti.com (157.170.170.75) by DLEE70.ent.ti.com (157.170.170.113) with Microsoft SMTP Server id 14.3.224.2; Thu, 4 Feb 2016 23:46:01 -0600 Received: from a0131933.apr.dhcp.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep33.itg.ti.com (8.14.3/8.13.8) with ESMTP id u155jt5m016552; Thu, 4 Feb 2016 23:45:59 -0600 From: Lokesh Vutla To: Tony Lindgren , Paul Walmsley CC: Linux OMAP Mailing List , Linux ARM Mailing List , Tero Kristo , Sekhar Nori , Nishanth Menon , Lokesh Vutla Subject: [PATCH v4 1/3] ARM: hwmod: RTC: Add lock and unlock functions Date: Fri, 5 Feb 2016 11:12:30 +0530 Message-ID: <1454650952-20154-2-git-send-email-lokeshvutla@ti.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1454650952-20154-1-git-send-email-lokeshvutla@ti.com> References: <1454650952-20154-1-git-send-email-lokeshvutla@ti.com> MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP RTC IP have kicker feature which prevents spurious writes to its registers. In order to write into any of the RTC registers, KICK values has to be written to KICK registers. Introduce omap_hwmod_rtc_unlock/lock functions, which writes into these KICK registers inorder to lock and unlock RTC registers. Signed-off-by: Lokesh Vutla --- arch/arm/mach-omap2/omap_hwmod.h | 2 ++ arch/arm/mach-omap2/omap_hwmod_reset.c | 65 ++++++++++++++++++++++++++++++++++ 2 files changed, 67 insertions(+) diff --git a/arch/arm/mach-omap2/omap_hwmod.h b/arch/arm/mach-omap2/omap_hwmod.h index 76bce11..649576e 100644 --- a/arch/arm/mach-omap2/omap_hwmod.h +++ b/arch/arm/mach-omap2/omap_hwmod.h @@ -751,6 +751,8 @@ const char *omap_hwmod_get_main_clk(struct omap_hwmod *oh); */ extern int omap_hwmod_aess_preprogram(struct omap_hwmod *oh); +void omap_hwmod_rtc_unlock(struct omap_hwmod *oh); +void omap_hwmod_rtc_lock(struct omap_hwmod *oh); /* * Chip variant-specific hwmod init routines - XXX should be converted diff --git a/arch/arm/mach-omap2/omap_hwmod_reset.c b/arch/arm/mach-omap2/omap_hwmod_reset.c index 65e186c..0e21daa 100644 --- a/arch/arm/mach-omap2/omap_hwmod_reset.c +++ b/arch/arm/mach-omap2/omap_hwmod_reset.c @@ -29,6 +29,16 @@ #include #include "omap_hwmod.h" +#include "common.h" + +#define OMAP_RTC_STATUS_REG 0x44 +#define OMAP_RTC_KICK0_REG 0x6c +#define OMAP_RTC_KICK1_REG 0x70 + +#define OMAP_RTC_KICK0_VALUE 0x83E70B13 +#define OMAP_RTC_KICK1_VALUE 0x95A4F1E0 +#define OMAP_RTC_STATUS_BUSY BIT(0) +#define OMAP_RTC_MAX_READY_TIME 50 /** * omap_hwmod_aess_preprogram - enable AESS internal autogating @@ -51,3 +61,58 @@ int omap_hwmod_aess_preprogram(struct omap_hwmod *oh) return 0; } + +/** + * omap_rtc_wait_not_busy - Wait for the RTC BUSY flag + * @oh: struct omap_hwmod * + * + * For updating certain RTC registers, the MPU must wait + * for the BUSY status in OMAP_RTC_STATUS_REG to become zero. + * Once the BUSY status is zero, there is a 15-?s access + * period in which the MPU can program. + */ +static void omap_rtc_wait_not_busy(struct omap_hwmod *oh) +{ + int i; + + /* BUSY may stay active for 1/32768 second (~30 usec) */ + omap_test_timeout(omap_hwmod_read(oh, OMAP_RTC_STATUS_REG) + & OMAP_RTC_STATUS_REG, OMAP_RTC_MAX_READY_TIME, i); + /* now we have ~15 usec to read/write various registers */ +} + +/** + * omap_hwmod_rtc_unlock - Unlock the Kicker mechanism. + * @oh: struct omap_hwmod * + * + * RTC IP have kicker feature. This prevents spurious writes to its registers. + * In order to write into any of the RTC registers, KICK values has te be + * written in respective KICK registers. This is needed for hwmod to write into + * sysconfig register. + */ +void omap_hwmod_rtc_unlock(struct omap_hwmod *oh) +{ + local_irq_disable(); + omap_rtc_wait_not_busy(oh); + omap_hwmod_write(OMAP_RTC_KICK0_VALUE, oh, OMAP_RTC_KICK0_REG); + omap_hwmod_write(OMAP_RTC_KICK1_VALUE, oh, OMAP_RTC_KICK1_REG); + local_irq_enable(); +} + +/** + * omap_hwmod_rtc_lock - Lock the Kicker mechanism. + * @oh: struct omap_hwmod * + * + * RTC IP have kicker feature. This prevents spurious writes to its registers. + * Once the RTC registers are written, KICK mechanism needs to be locked, + * in order to prevent any spurious writes. This function locks back the RTC + * registers once hwmod completes its write into sysconfig register. + */ +void omap_hwmod_rtc_lock(struct omap_hwmod *oh) +{ + local_irq_disable(); + omap_rtc_wait_not_busy(oh); + omap_hwmod_write(0x0, oh, OMAP_RTC_KICK0_REG); + omap_hwmod_write(0x0, oh, OMAP_RTC_KICK1_REG); + local_irq_enable(); +}