From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH V11 08/11] drivers: acpi: Handle IOMMU lookup failure with deferred probing or error Date: Tue, 23 May 2017 09:52:41 +0100 Message-ID: <20170523085241.GA18204@red-moon> References: <1491823266-1209-1-git-send-email-sricharan@codeaurora.org> <1491823266-1209-9-git-send-email-sricharan@codeaurora.org> <41668eff-271c-1c4c-7665-3bf0faa74669@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <41668eff-271c-1c4c-7665-3bf0faa74669-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Nate Watterson Cc: gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, catalin.marinas-5wv7dgnIgG8@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, okaya-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, tn-nYOzD4b6Jr9Wk0Htik3J/w@public.gmane.org, linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lenb-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, sudeep.holla-5wv7dgnIgG8@public.gmane.org List-Id: devicetree@vger.kernel.org On Tue, May 23, 2017 at 02:26:10AM -0400, Nate Watterson wrote: > Hi Sricharan, > > On 4/10/2017 7:21 AM, Sricharan R wrote: > >This is an equivalent to the DT's handling of the iommu master's probe > >with deferred probing when the corrsponding iommu is not probed yet. > >The lack of a registered IOMMU can be caused by the lack of a driver for > >the IOMMU, the IOMMU device probe not having been performed yet, having > >been deferred, or having failed. > > > >The first case occurs when the firmware describes the bus master and > >IOMMU topology correctly but no device driver exists for the IOMMU yet > >or the device driver has not been compiled in. Return NULL, the caller > >will configure the device without an IOMMU. > > > >The second and third cases are handled by deferring the probe of the bus > >master device which will eventually get reprobed after the IOMMU. > > > >The last case is currently handled by deferring the probe of the bus > >master device as well. A mechanism to either configure the bus master > >device without an IOMMU or to fail the bus master device probe depending > >on whether the IOMMU is optional or mandatory would be a good > >enhancement. > > > >Tested-by: Hanjun Guo > >Reviewed-by: Robin Murphy > >[Lorenzo: Added fixes for dma_coherent_mask overflow, acpi_dma_configure > > called multiple times for same device] > >Signed-off-by: Lorenzo Pieralisi > >Signed-off-by: Sricharan R > >--- > > drivers/acpi/arm64/iort.c | 33 ++++++++++++++++++++++++++++++++- > > drivers/acpi/scan.c | 11 ++++++++--- > > drivers/base/dma-mapping.c | 2 +- > > include/acpi/acpi_bus.h | 2 +- > > include/linux/acpi.h | 7 +++++-- > > 5 files changed, 47 insertions(+), 8 deletions(-) > > > >diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c > >index 3dd9ec3..e323ece 100644 > >--- a/drivers/acpi/arm64/iort.c > >+++ b/drivers/acpi/arm64/iort.c > >@@ -543,6 +543,14 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev, > > const struct iommu_ops *ops = NULL; > > int ret = -ENODEV; > > struct fwnode_handle *iort_fwnode; > >+ struct iommu_fwspec *fwspec = dev->iommu_fwspec; > >+ > >+ /* > >+ * If we already translated the fwspec there > >+ * is nothing left to do, return the iommu_ops. > >+ */ > >+ if (fwspec && fwspec->ops) > >+ return fwspec->ops; > > Is this logic strictly required? It breaks masters with multiple SIDs > as only the first SID is actually added to the master's fwspec. My bad, that's indeed a silly bug I introduced. Please let me know if the patch below fixes it, we will send it upstream shortly. Lorenzo -- >8 -- diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index c5fecf9..e326f2a 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -666,14 +666,6 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev, int ret = -ENODEV; struct fwnode_handle *iort_fwnode; - /* - * If we already translated the fwspec there - * is nothing left to do, return the iommu_ops. - */ - ops = iort_fwspec_iommu_ops(dev->iommu_fwspec); - if (ops) - return ops; - if (node) { iort_fwnode = iort_get_fwnode(node); if (!iort_fwnode) @@ -735,6 +727,14 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev) u32 streamid = 0; int err; + /* + * If we already translated the fwspec there + * is nothing left to do, return the iommu_ops. + */ + ops = iort_fwspec_iommu_ops(dev->iommu_fwspec); + if (ops) + return ops; + if (dev_is_pci(dev)) { struct pci_bus *bus = to_pci_dev(dev)->bus; u32 rid;