From mboxrd@z Thu Jan 1 00:00:00 1970 From: willy@linux.intel.com (Matthew Wilcox) Date: Fri, 1 Mar 2013 10:12:19 -0500 Subject: [PATCH 1/2] Add support for 32 bit DMA for 32 bit machines In-Reply-To: References: Message-ID: <20130301151219.GF4530@linux.intel.com> On Thu, Feb 28, 2013@07:49:13PM +0000, Chayan Biswas wrote: > We set the DMA mask to 32 bit if the system is a 32 bit system. We also > try to set to 32 bit DMA if setting the 64 bit DMA fails, and clean up > if both fails. What problem are you solving here? If the system is 32-bit, setting the DMA mask to 64-bit should be harmless. The DMA mask tells the system what the device is capable of -- this doesn't change if the system happens to be 32-bit. > Signed-off-by: Chayan Biswas > --- > drivers/block/nvme.c | 19 +++++++++++++++++-- > 1 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c > index 993c014..4b706b5 100644 > --- a/drivers/block/nvme.c > +++ b/drivers/block/nvme.c > @@ -42,6 +42,7 @@ > > #include > > +#define IS_DMA64 (sizeof(dma_addr_t) == 8) > #define NVME_Q_DEPTH 1024 > #define SQ_SIZE(depth) (depth * sizeof(struct nvme_command)) > #define CQ_SIZE(depth) (depth * sizeof(struct nvme_completion)) > @@ -1662,8 +1663,21 @@ static int __devinit nvme_probe(struct pci_dev *pdev, > INIT_LIST_HEAD(&dev->namespaces); > dev->pci_dev = pdev; > pci_set_drvdata(pdev, dev); > - dma_set_mask(&pdev->dev, DMA_BIT_MASK(64)); > - dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64)); > + if (IS_DMA64) { > + if (dma_set_mask(&pdev->dev, DMA_BIT_MASK(64)) != 0) { > + if (dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)) != 0) > + goto fail_set_dma_mask; > + > + dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32)); > + } else { > + dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64)); > + } > + } else { > + if (dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)) != 0) > + goto fail_set_dma_mask; > + > + dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32)); > + } > result = nvme_set_instance(dev); > if (result) > goto disable; > @@ -1705,6 +1719,7 @@ static int __devinit nvme_probe(struct pci_dev *pdev, > iounmap(dev->bar); > disable_msix: > pci_disable_msix(pdev); > + fail_set_dma_mask: > nvme_release_instance(dev); > nvme_release_prp_pools(dev); > disable: > -- > 1.7.1 > > > ________________________________ > > PLEASE NOTE: The information contained in this electronic mail message is intended only for the use of the designated recipient(s) named above. If the reader of this message is not the intended recipient, you are hereby notified that you have received this message in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify the sender by telephone or e-mail (as shown above) immediately and destroy any and all copies of this message in your possession (whether hard copies or electronically stored copies). > > > _______________________________________________ > Linux-nvme mailing list > Linux-nvme at lists.infradead.org > http://merlin.infradead.org/mailman/listinfo/linux-nvme