From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934295AbbA1CZs (ORCPT ); Tue, 27 Jan 2015 21:25:48 -0500 Received: from eusmtp01.atmel.com ([212.144.249.242]:38651 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933308AbbA1CZq (ORCPT ); Tue, 27 Jan 2015 21:25:46 -0500 From: Wenyou Yang To: , CC: , , , , , , , Subject: [PATCH v2 1/3] pm: at91: pm_suspend: add the WFI support for ARMv7 Date: Wed, 28 Jan 2015 10:22:37 +0800 Message-ID: <1422411757-13066-1-git-send-email-wenyou.yang@atmel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1422411707-10945-1-git-send-email-wenyou.yang@atmel.com> References: <1422411707-10945-1-git-send-email-wenyou.yang@atmel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add the WFI support to put the cpu to the sleep state. In the meanwhile, disable the processor's clock. Signed-off-by: Wenyou Yang --- arch/arm/mach-at91/pm_suspend.S | 49 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 48 insertions(+), 1 deletion(-) diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S index 122a3f1..aed6903 100644 --- a/arch/arm/mach-at91/pm_suspend.S +++ b/arch/arm/mach-at91/pm_suspend.S @@ -53,6 +53,53 @@ mode .req r6 beq 1b .endm +/* + * Put the processor to enter the WFI state + */ + .macro _do_wfi + +#if defined(CONFIG_CPU_V7) + /* + * Execute an ISB instruction to flush the pipeline to ensure + * that all of operations have beem completed. + */ + isb + + dsb + dmb + + /* Disable the processor's clock */ + mov tmp1, #AT91_PMC_PCK + str tmp1, [pmc, #AT91_PMC_SCDR] + + wfi + + /* + * CPU can speculatively prefetch the instructions + * so add NOPs after WFI. Sixteen NOPs as Cortex-A5 pipeline. + */ + nop + nop + nop + nop + nop + nop + nop + nop + nop + nop + nop + nop + nop + nop + nop + nop +#else + mcr p15, 0, tmp1, c7, c0, 4 +#endif + + .endm + .text /* @@ -181,7 +228,7 @@ sdr_sr_done: skip_disable_main_clock: /* Wait for interrupt */ - mcr p15, 0, tmp1, c7, c0, 4 + _do_wfi tst mode, #AT91_PM_SLOW_CLOCK beq skip_enable_main_clock -- 1.7.9.5