From patchwork Wed Oct 31 10:43:14 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Paul Walmsley X-Patchwork-Id: 1678261 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id E263DDF2F6 for ; Wed, 31 Oct 2012 10:46:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756752Ab2JaKql (ORCPT ); Wed, 31 Oct 2012 06:46:41 -0400 Received: from utopia.booyaka.com ([74.50.51.50]:51171 "EHLO utopia.booyaka.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756730Ab2JaKqj (ORCPT ); Wed, 31 Oct 2012 06:46:39 -0400 Received: (qmail 11025 invoked by uid 1019); 31 Oct 2012 10:46:38 -0000 MBOX-Line: From nobody Wed Oct 31 04:43:14 2012 Subject: [PATCH 3/4] ARM: OMAP2+: hwmod: add flag to prevent hwmod code from touching IP block during init To: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org From: Paul Walmsley Cc: =?utf-8?q?Beno=C3=AEt?= Cousson Date: Wed, 31 Oct 2012 04:43:14 -0600 Message-ID: <20121031104313.6557.6835.stgit@dusk.lan> In-Reply-To: <20121031103607.6557.64591.stgit@dusk.lan> References: <20121031103607.6557.64591.stgit@dusk.lan> User-Agent: StGit/0.16-37-g27ac3 MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org Add HWMOD_EXT_OPT_MAIN_CLK flag to indicate that this IP block is dependent on an off-chip functional clock that is not guaranteed to be present during initialization. IP blocks marked with this flag are left in the INITIALIZED state during kernel init. This is a workaround for a hardware problem. It should be possible to guarantee that at least one clock source will be present and active for any IP block's main functional clock. This ensures that the hwmod code can enable and reset the IP block. Resetting the IP block during kernel init prevents any bogus bootloader, ROM code, or previous OS configuration from affecting the kernel. Hopefully a clock multiplexer can be added on future SoCs. N.B., at some point in the future, it should be possible to query the clock framework for this type of information. Then this flag should no longer be needed. Signed-off-by: Paul Walmsley Cc: Benoît Cousson --- arch/arm/mach-omap2/omap_hwmod.c | 3 +++ arch/arm/plat-omap/include/plat/omap_hwmod.h | 6 ++++++ 2 files changed, 9 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c index f9d8b2a..4529650 100644 --- a/arch/arm/mach-omap2/omap_hwmod.c +++ b/arch/arm/mach-omap2/omap_hwmod.c @@ -2380,6 +2380,9 @@ static int __init _setup_reset(struct omap_hwmod *oh) if (oh->_state != _HWMOD_STATE_INITIALIZED) return -EINVAL; + if (oh->flags & HWMOD_EXT_OPT_MAIN_CLK) + return -EPERM; + if (oh->rst_lines_cnt == 0) { r = _enable(oh); if (r) { diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h index b3349f7..1db0294 100644 --- a/arch/arm/plat-omap/include/plat/omap_hwmod.h +++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h @@ -443,6 +443,11 @@ struct omap_hwmod_omap4_prcm { * in order to complete the reset. Optional clocks will be disabled * again after the reset. * HWMOD_16BIT_REG: Module has 16bit registers + * HWMOD_EXT_OPT_MAIN_CLK: The only main functional clock source for + * this IP block comes from an off-chip source and is not always + * enabled. This prevents the hwmod code from being able to + * enable and reset the IP block early. XXX Eventually it should + * be possible to query the clock framework for this information. */ #define HWMOD_SWSUP_SIDLE (1 << 0) #define HWMOD_SWSUP_MSTANDBY (1 << 1) @@ -453,6 +458,7 @@ struct omap_hwmod_omap4_prcm { #define HWMOD_NO_IDLEST (1 << 6) #define HWMOD_CONTROL_OPT_CLKS_IN_RESET (1 << 7) #define HWMOD_16BIT_REG (1 << 8) +#define HWMOD_EXT_OPT_MAIN_CLK (1 << 9) /* * omap_hwmod._int_flags definitions