From patchwork Wed Apr 20 19:28:46 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Walmsley X-Patchwork-Id: 722861 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p3KJjiID031586 for ; Wed, 20 Apr 2011 19:45:48 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755861Ab1DTTpr (ORCPT ); Wed, 20 Apr 2011 15:45:47 -0400 Received: from utopia.booyaka.com ([72.9.107.138]:49015 "EHLO utopia.booyaka.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755863Ab1DTTpp (ORCPT ); Wed, 20 Apr 2011 15:45:45 -0400 Received: (qmail 11638 invoked by uid 1019); 20 Apr 2011 19:45:44 -0000 MBOX-Line: From nobody Wed Apr 20 13:28:46 2011 Subject: [PATCH 4/5] OMAP3: PM: Do not rely on ROM code to restore CM_AUTOIDLE_PLL.AUTO_PERIPH_DPLL To: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org From: Paul Walmsley Cc: Eduardo Valentin Date: Wed, 20 Apr 2011 13:28:46 -0600 Message-ID: <20110420192843.16986.26268.stgit@twilight.localdomain> In-Reply-To: <20110420192601.16986.56558.stgit@twilight.localdomain> References: <20110420192601.16986.56558.stgit@twilight.localdomain> User-Agent: StGit/0.15 MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Wed, 20 Apr 2011 19:45:48 +0000 (UTC) From: Eduardo Valentin As per OMAP3 erratum (i671), ROM code adds extra latencies while restoring CM_AUTOIDLE_PLL register, if AUTO_PERIPH_DPLL is equal to 1. This patch stores 0's in scratchpad content area corresponding to AUTO_PERIPH_DPLL, to prevent ROM code to try to lock per DPLL, since it won't respect proper programing scheme. This register is then stored in prcm context. The saving and restore is now done by kernel side. Here follow the erratum description DESCRIPTION After OFF mode transition, among many restorations, the ROM Code restores the CM_AUTOIDLE_PLL register, and after that, it tries to relock the PER DPLL. In case the restoration data stored in scratchpad memory contains a field CM_AUTOIDLE_PLL.AUTO_PERIPH_DPLL = 1, then the way the ROM Code restores and locks the PER DPLL does not respect the PER DPLL programming scheme. In that case, the DPLL might not lock. Meanwhile, when trying to lock the PER DPLL, the ROM Code does not hang. Only extra latencies are introduced at wake-up. WORKAROUND When saving the context-restore structure in scratchpad memory, in order to respect the PER DPLL programming scheme, it is advised to store 0 in the CM_AUTOIDLE_PLL.AUTO_PERIPH_DPLL field of the saved structure. After wake-up, the application should store in CM_AUTOIDLE_PLL register the right desired value. Signed-off-by: Eduardo Valentin Signed-off-by: Paul Walmsley --- arch/arm/mach-omap2/cm2xxx_3xxx.c | 17 +++++++++++++++++ arch/arm/mach-omap2/control.c | 8 +++++++- 2 files changed, 24 insertions(+), 1 deletions(-) -- 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/cm2xxx_3xxx.c b/arch/arm/mach-omap2/cm2xxx_3xxx.c index 9d0dec8..38830d8 100644 --- a/arch/arm/mach-omap2/cm2xxx_3xxx.c +++ b/arch/arm/mach-omap2/cm2xxx_3xxx.c @@ -247,6 +247,7 @@ struct omap3_cm_regs { u32 per_cm_clksel; u32 emu_cm_clksel; u32 emu_cm_clkstctrl; + u32 pll_cm_autoidle; u32 pll_cm_autoidle2; u32 pll_cm_clksel4; u32 pll_cm_clksel5; @@ -319,6 +320,15 @@ void omap3_cm_save_context(void) omap2_cm_read_mod_reg(OMAP3430_EMU_MOD, CM_CLKSEL1); cm_context.emu_cm_clkstctrl = omap2_cm_read_mod_reg(OMAP3430_EMU_MOD, OMAP2_CM_CLKSTCTRL); + /* + * As per erratum i671, ROM code does not respect the PER DPLL + * programming scheme if CM_AUTOIDLE_PLL.AUTO_PERIPH_DPLL == 1. + * In this case, even though this register has been saved in + * scratchpad contents, we need to restore AUTO_PERIPH_DPLL + * by ourselves. So, we need to save it anyway. + */ + cm_context.pll_cm_autoidle = + omap2_cm_read_mod_reg(PLL_MOD, CM_AUTOIDLE); cm_context.pll_cm_autoidle2 = omap2_cm_read_mod_reg(PLL_MOD, CM_AUTOIDLE2); cm_context.pll_cm_clksel4 = @@ -441,6 +451,13 @@ void omap3_cm_restore_context(void) CM_CLKSEL1); omap2_cm_write_mod_reg(cm_context.emu_cm_clkstctrl, OMAP3430_EMU_MOD, OMAP2_CM_CLKSTCTRL); + /* + * As per erratum i671, ROM code does not respect the PER DPLL + * programming scheme if CM_AUTOIDLE_PLL.AUTO_PERIPH_DPLL == 1. + * In this case, we need to restore AUTO_PERIPH_DPLL by ourselves. + */ + omap2_cm_write_mod_reg(cm_context.pll_cm_autoidle, PLL_MOD, + CM_AUTOIDLE); omap2_cm_write_mod_reg(cm_context.pll_cm_autoidle2, PLL_MOD, CM_AUTOIDLE2); omap2_cm_write_mod_reg(cm_context.pll_cm_clksel4, PLL_MOD, diff --git a/arch/arm/mach-omap2/control.c b/arch/arm/mach-omap2/control.c index df0c75c..da53ba3 100644 --- a/arch/arm/mach-omap2/control.c +++ b/arch/arm/mach-omap2/control.c @@ -316,8 +316,14 @@ void omap3_save_scratchpad_contents(void) omap2_cm_read_mod_reg(WKUP_MOD, CM_CLKSEL); prcm_block_contents.cm_clken_pll = omap2_cm_read_mod_reg(PLL_MOD, CM_CLKEN); + /* + * As per erratum i671, ROM code does not respect the PER DPLL + * programming scheme if CM_AUTOIDLE_PLL..AUTO_PERIPH_DPLL == 1. + * Then, in anycase, clear these bits to avoid extra latencies. + */ prcm_block_contents.cm_autoidle_pll = - omap2_cm_read_mod_reg(PLL_MOD, CM_AUTOIDLE); + omap2_cm_read_mod_reg(PLL_MOD, CM_AUTOIDLE) & + ~OMAP3430_AUTO_PERIPH_DPLL_MASK; prcm_block_contents.cm_clksel1_pll = omap2_cm_read_mod_reg(PLL_MOD, OMAP3430_CM_CLKSEL1_PLL); prcm_block_contents.cm_clksel2_pll =