Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752814AbcLEWet (ORCPT ); Mon, 5 Dec 2016 17:34:49 -0500 Received: from mail-wm0-f68.google.com ([74.125.82.68]:33168 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752440AbcLEWeq (ORCPT ); Mon, 5 Dec 2016 17:34:46 -0500 MIME-Version: 1.0 In-Reply-To: <20161205122619.25045-1-lorenzo.pieralisi@arm.com> References: <20161205122619.25045-1-lorenzo.pieralisi@arm.com> From: "Rafael J. Wysocki" Date: Mon, 5 Dec 2016 23:18:56 +0100 X-Google-Sender-Auth: ds7PscOsrAbfx2hkkchxMbgxB3I Message-ID: Subject: Re: [PATCH] ACPI/IORT: Make dma masks set-up IORT specific To: Lorenzo Pieralisi Cc: Joerg Roedel , "Rafael J. Wysocki" , "open list:AMD IOMMU (AMD-VI)" , Will Deacon , Hanjun Guo , Bjorn Helgaas , Robin Murphy , Tomasz Nowicki , Sricharan R , Sinan Kaya , Nate Watterson , Prem Mallappa , Dennis Chen , ACPI Devel Maling List , Linux PCI , Linux Kernel Mailing List , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5338 Lines: 136 On Mon, Dec 5, 2016 at 1:26 PM, Lorenzo Pieralisi wrote: > The introduction of acpi_dma_configure() allows to configure DMA > and related IOMMU for any device that is DMA capable. To achieve > that goal it ensures DMA masks are set-up to sane default values > before proceeding with IOMMU and DMA ops configuration. > > On x86/ia64 systems, through acpi_bind_one(), acpi_dma_configure() is > called for every device that has an ACPI companion, in that every device > is considered DMA capable on x86/ia64 systems (ie acpi_get_dma_attr() API), > which has the side effect of initializing dma masks also for > pseudo-devices (eg CPUs and memory nodes) and potentially for devices > whose dma masks were not set-up before the acpi_dma_configure() API was > introduced, which may have noxious side effects. > > Therefore, in preparation for IORT firmware specific DMA masks set-up, > wrap the default DMA masks set-up in acpi_dma_configure() inside an IORT > specific wrapper that reverts to a NOP on x86/ia64 systems, restoring the > default expected behaviour on x86/ia64 systems and keeping DMA default > masks set-up on IORT based (ie ARM) arch configurations. > > Signed-off-by: Lorenzo Pieralisi > Cc: Will Deacon > Cc: Hanjun Guo > Cc: Bjorn Helgaas > Cc: Robin Murphy > Cc: Tomasz Nowicki > Cc: Joerg Roedel > Cc: "Rafael J. Wysocki" > Cc: Sricharan R Acked -by: Rafael J. Wysocki > --- > Joerg, > > pending Rafael's ACK on it, given the 4.10 release timing and that the > series is queued via the IOMMU tree please consider applying this patch to > your arm/smmu branch for 4.10, it is not fixing a bug but it is modifying > the x86/ia64 code path; I prefer preventing any issue related to default > dma masks on x86/ia64 so I hope it can get merged along with the rest of > the ACPI IORT SMMU series. > > Thanks a lot and apologies, > Lorenzo > > drivers/acpi/arm64/iort.c | 22 ++++++++++++++++++++++ > drivers/acpi/scan.c | 14 +------------- > include/linux/acpi_iort.h | 2 ++ > 3 files changed, 25 insertions(+), 13 deletions(-) > > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c > index 47bace8..e0d2e6e 100644 > --- a/drivers/acpi/arm64/iort.c > +++ b/drivers/acpi/arm64/iort.c > @@ -547,6 +547,28 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev, > } > > /** > + * iort_set_dma_mask - Set-up dma mask for a device. > + * > + * @dev: device to configure > + */ > +void iort_set_dma_mask(struct device *dev) > +{ > + /* > + * Set default coherent_dma_mask to 32 bit. Drivers are expected to > + * setup the correct supported mask. > + */ > + if (!dev->coherent_dma_mask) > + dev->coherent_dma_mask = DMA_BIT_MASK(32); > + > + /* > + * Set it to coherent_dma_mask by default if the architecture > + * code has not set it. > + */ > + if (!dev->dma_mask) > + dev->dma_mask = &dev->coherent_dma_mask; > +} > + > +/** > * iort_iommu_configure - Set-up IOMMU configuration for a device. > * > * @dev: device to configure > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index 80698d3..93b00cf 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -1380,19 +1380,7 @@ void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) > { > const struct iommu_ops *iommu; > > - /* > - * Set default coherent_dma_mask to 32 bit. Drivers are expected to > - * setup the correct supported mask. > - */ > - if (!dev->coherent_dma_mask) > - dev->coherent_dma_mask = DMA_BIT_MASK(32); > - > - /* > - * Set it to coherent_dma_mask by default if the architecture > - * code has not set it. > - */ > - if (!dev->dma_mask) > - dev->dma_mask = &dev->coherent_dma_mask; > + iort_set_dma_mask(dev); > > iommu = iort_iommu_configure(dev); > > diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h > index dcb2b60..77e0809 100644 > --- a/include/linux/acpi_iort.h > +++ b/include/linux/acpi_iort.h > @@ -35,6 +35,7 @@ bool iort_node_match(u8 type); > u32 iort_msi_map_rid(struct device *dev, u32 req_id); > struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id); > /* IOMMU interface */ > +void iort_set_dma_mask(struct device *dev); > const struct iommu_ops *iort_iommu_configure(struct device *dev); > #else > static inline void acpi_iort_init(void) { } > @@ -45,6 +46,7 @@ static inline struct irq_domain *iort_get_device_domain(struct device *dev, > u32 req_id) > { return NULL; } > /* IOMMU interface */ > +static inline void iort_set_dma_mask(struct device *dev) { } > static inline > const struct iommu_ops *iort_iommu_configure(struct device *dev) > { return NULL; } > -- > 2.10.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html