Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965931AbcCPIrS (ORCPT ); Wed, 16 Mar 2016 04:47:18 -0400 Received: from mga14.intel.com ([192.55.52.115]:18840 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965649AbcCPIrL (ORCPT ); Wed, 16 Mar 2016 04:47:11 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,343,1455004800"; d="scan'208";a="67310488" Subject: Re: [PATCH v4 1/3] mmc: sdhci: Set DMA mask when adding host To: Alexandre Courbot , Ulf Hansson , Arnd Bergmann References: <1457316477-8153-1-git-send-email-acourbot@nvidia.com> <1457316477-8153-2-git-send-email-acourbot@nvidia.com> Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, gnurou@gmail.com From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <56E91CB5.7030007@intel.com> Date: Wed, 16 Mar 2016 10:43:33 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1457316477-8153-2-git-send-email-acourbot@nvidia.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2626 Lines: 84 On 07/03/16 04:07, Alexandre Courbot wrote: > Set the DMA mask in sdhci_add_host() after we determined the > capabilities of the device. 64-bit devices in particular are given the > proper mask that ensures bounce buffers are not used. > > Also disable DMA if no proper DMA mask can be set, as the DMA-API > documentation specifies. > > Signed-off-by: Alexandre Courbot > --- > drivers/mmc/host/sdhci.c | 48 +++++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 41 insertions(+), 7 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index fd9139947fa3..920e1c996280 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -2857,6 +2857,36 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev, > > EXPORT_SYMBOL_GPL(sdhci_alloc_host); > > +static int sdhci_set_dma_mask(struct sdhci_host *host) > +{ > + struct mmc_host *mmc = host->mmc; > + struct device *dev = mmc_dev(mmc); > + int ret = -EINVAL; > + > + if (host->quirks2 & SDHCI_QUIRK2_BROKEN_64_BIT_DMA) > + host->flags &= ~SDHCI_USE_64_BIT_DMA; > + > + /* Try 64-bit mask if hardware is capable of it */ > + if (host->flags & SDHCI_USE_64_BIT_DMA) { > + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64)); > + if (ret) { > + pr_warn("%s: Failed to set 64-bit DMA mask.\n", > + mmc_hostname(mmc)); > + host->flags &= ~SDHCI_USE_64_BIT_DMA; > + } > + } > + > + /* 32-bit mask as default & fallback */ > + if (ret) { > + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); What happens if device enumeration (e.g. of_dma_configure) has already set a more restrictive DMA mask? > + if (ret) > + pr_warn("%s: Failed to set 32-bit DMA mask.\n", > + mmc_hostname(mmc)); > + } > + > + return ret; > +} > + > int sdhci_add_host(struct sdhci_host *host) > { > struct mmc_host *mmc; > @@ -2932,13 +2962,17 @@ int sdhci_add_host(struct sdhci_host *host) > host->flags |= SDHCI_USE_64_BIT_DMA; > > if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA)) { > - if (host->ops->enable_dma) { > - if (host->ops->enable_dma(host)) { > - pr_warn("%s: No suitable DMA available - falling back to PIO\n", > - mmc_hostname(mmc)); > - host->flags &= > - ~(SDHCI_USE_SDMA | SDHCI_USE_ADMA); > - } > + ret = sdhci_set_dma_mask(host); > + > + if (!ret && host->ops->enable_dma) > + ret = host->ops->enable_dma(host); > + > + if (ret) { > + pr_warn("%s: No suitable DMA available - falling back to PIO\n", > + mmc_hostname(mmc)); > + host->flags &= ~(SDHCI_USE_SDMA | SDHCI_USE_ADMA); > + > + ret = 0; > } > } > >