From patchwork Tue Sep 17 12:38:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fabrice Gasnier X-Patchwork-Id: 11148719 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BA4EF14F7 for ; Tue, 17 Sep 2019 12:39:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8EC3A218AF for ; Tue, 17 Sep 2019 12:39:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="Ft6l6A+L" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727112AbfIQMjW (ORCPT ); Tue, 17 Sep 2019 08:39:22 -0400 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:34266 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726946AbfIQMjV (ORCPT ); Tue, 17 Sep 2019 08:39:21 -0400 Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id x8HCUsGj028794; Tue, 17 Sep 2019 14:38:44 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=STMicroelectronics; bh=QkRCYsDXVXhFgyT8aCcIU1yLANBURobzqeomhnBIHLE=; b=Ft6l6A+LX9udX9LGWjbwgFpHqZt7GblezpZjY42GBsw2xvwZG5DRQElZBGoPgm8WTkQW 8U2GNIZXHblsCHQsVlYRrrwz+V/39Ckst8fK+B3A5BryLfcm2doS2BNl0c3e/WzumTyP slb9JEj/1RzKZgHo8jWEEf6gikv9KbgnHWpu9Vv5wevzvWABxQrHXhVw22xKRZVoYdwV es8La7+RYl5ARoMaTusjibJ4/yfswYsJxDyBUuuE7sk3hqgKvlk2xxW4Qhhhzt+BvKWt 9/3pmYWeSeMlZRreA/tzLur7mv8Vw8HKks3VcoTSBVIYYw5zF7yuIC/XcEKlA4Tq7WCC qQ== Received: from beta.dmz-ap.st.com (beta.dmz-ap.st.com [138.198.100.35]) by mx07-00178001.pphosted.com with ESMTP id 2v0np11k7a-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT); Tue, 17 Sep 2019 14:38:44 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-ap.st.com (STMicroelectronics) with ESMTP id 1444D52; Tue, 17 Sep 2019 12:38:36 +0000 (GMT) Received: from Webmail-eu.st.com (Safex1hubcas24.st.com [10.75.90.94]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id C166E2BCDD9; Tue, 17 Sep 2019 14:38:35 +0200 (CEST) Received: from SAFEX1HUBCAS22.st.com (10.75.90.92) by Safex1hubcas24.st.com (10.75.90.94) with Microsoft SMTP Server (TLS) id 14.3.439.0; Tue, 17 Sep 2019 14:38:35 +0200 Received: from localhost (10.48.1.232) by Webmail-ga.st.com (10.75.90.48) with Microsoft SMTP Server (TLS) id 14.3.439.0; Tue, 17 Sep 2019 14:38:35 +0200 From: Fabrice Gasnier To: CC: , , , , , , , , , Subject: [PATCH v2 2/2] iio: adc: stm32-adc: fix a race when using several adcs with dma and irq Date: Tue, 17 Sep 2019 14:38:16 +0200 Message-ID: <1568723896-19063-3-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1568723896-19063-1-git-send-email-fabrice.gasnier@st.com> References: <1568723896-19063-1-git-send-email-fabrice.gasnier@st.com> MIME-Version: 1.0 X-Originating-IP: [10.48.1.232] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.70,1.0.8 definitions=2019-09-17_06:2019-09-17,2019-09-17 signatures=0 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org End of conversion may be handled by using IRQ or DMA. There may be a race when two conversions complete at the same time on several ADCs. EOC can be read as 'set' for several ADCs, with: - an ADC configured to use IRQs. EOCIE bit is set. The handler is normally called in this case. - an ADC configured to use DMA. EOCIE bit isn't set. EOC triggers the DMA request instead. It's then automatically cleared by DMA read. But the handler gets called due to status bit is temporarily set (IRQ triggered by the other ADC). So both EOC status bit in CSR and EOCIE control bit must be checked before invoking the interrupt handler (e.g. call ISR only for IRQ-enabled ADCs). Fixes: 2763ea0585c9 ("iio: adc: stm32: add optional dma support") Signed-off-by: Fabrice Gasnier --- Changes in v2: - Keep registers definitions as a whole block to ease readability (add a precursor patch to move them to header file) --- drivers/iio/adc/stm32-adc-core.c | 43 +++++++++++++++++++++++++++++++++++++--- drivers/iio/adc/stm32-adc-core.h | 1 + 2 files changed, 41 insertions(+), 3 deletions(-) diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c index 84ac326..93a096a 100644 --- a/drivers/iio/adc/stm32-adc-core.c +++ b/drivers/iio/adc/stm32-adc-core.c @@ -44,6 +44,8 @@ * @eoc1: adc1 end of conversion flag in @csr * @eoc2: adc2 end of conversion flag in @csr * @eoc3: adc3 end of conversion flag in @csr + * @ier: interrupt enable register offset for each adc + * @eocie_msk: end of conversion interrupt enable mask in @ier */ struct stm32_adc_common_regs { u32 csr; @@ -51,6 +53,8 @@ struct stm32_adc_common_regs { u32 eoc1_msk; u32 eoc2_msk; u32 eoc3_msk; + u32 ier; + u32 eocie_msk; }; struct stm32_adc_priv; @@ -276,6 +280,8 @@ static const struct stm32_adc_common_regs stm32f4_adc_common_regs = { .eoc1_msk = STM32F4_EOC1, .eoc2_msk = STM32F4_EOC2, .eoc3_msk = STM32F4_EOC3, + .ier = STM32F4_ADC_CR1, + .eocie_msk = STM32F4_EOCIE, }; /* STM32H7 common registers definitions */ @@ -284,8 +290,24 @@ static const struct stm32_adc_common_regs stm32h7_adc_common_regs = { .ccr = STM32H7_ADC_CCR, .eoc1_msk = STM32H7_EOC_MST, .eoc2_msk = STM32H7_EOC_SLV, + .ier = STM32H7_ADC_IER, + .eocie_msk = STM32H7_EOCIE, }; +static const unsigned int stm32_adc_offset[STM32_ADC_MAX_ADCS] = { + 0, STM32_ADC_OFFSET, STM32_ADC_OFFSET * 2, +}; + +static unsigned int stm32_adc_eoc_enabled(struct stm32_adc_priv *priv, + unsigned int adc) +{ + u32 ier, offset = stm32_adc_offset[adc]; + + ier = readl_relaxed(priv->common.base + offset + priv->cfg->regs->ier); + + return ier & priv->cfg->regs->eocie_msk; +} + /* ADC common interrupt for all instances */ static void stm32_adc_irq_handler(struct irq_desc *desc) { @@ -296,13 +318,28 @@ static void stm32_adc_irq_handler(struct irq_desc *desc) chained_irq_enter(chip, desc); status = readl_relaxed(priv->common.base + priv->cfg->regs->csr); - if (status & priv->cfg->regs->eoc1_msk) + /* + * End of conversion may be handled by using IRQ or DMA. There may be a + * race here when two conversions complete at the same time on several + * ADCs. EOC may be read 'set' for several ADCs, with: + * - an ADC configured to use DMA (EOC triggers the DMA request, and + * is then automatically cleared by DR read in hardware) + * - an ADC configured to use IRQs (EOCIE bit is set. The handler must + * be called in this case) + * So both EOC status bit in CSR and EOCIE control bit must be checked + * before invoking the interrupt handler (e.g. call ISR only for + * IRQ-enabled ADCs). + */ + if (status & priv->cfg->regs->eoc1_msk && + stm32_adc_eoc_enabled(priv, 0)) generic_handle_irq(irq_find_mapping(priv->domain, 0)); - if (status & priv->cfg->regs->eoc2_msk) + if (status & priv->cfg->regs->eoc2_msk && + stm32_adc_eoc_enabled(priv, 1)) generic_handle_irq(irq_find_mapping(priv->domain, 1)); - if (status & priv->cfg->regs->eoc3_msk) + if (status & priv->cfg->regs->eoc3_msk && + stm32_adc_eoc_enabled(priv, 2)) generic_handle_irq(irq_find_mapping(priv->domain, 2)); chained_irq_exit(chip, desc); diff --git a/drivers/iio/adc/stm32-adc-core.h b/drivers/iio/adc/stm32-adc-core.h index 94aa2d2..2579d51 100644 --- a/drivers/iio/adc/stm32-adc-core.h +++ b/drivers/iio/adc/stm32-adc-core.h @@ -25,6 +25,7 @@ * -------------------------------------------------------- */ #define STM32_ADC_MAX_ADCS 3 +#define STM32_ADC_OFFSET 0x100 #define STM32_ADCX_COMN_OFFSET 0x300 /* STM32F4 - Registers for each ADC instance */