From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 77F39B6F93 for ; Thu, 23 Jun 2011 21:34:08 +1000 (EST) From: Kumar Gala To: Greg KH Subject: [PATCH v3 3/3] powerpc: Dont require a dma_ops struct to set dma mask Date: Thu, 23 Jun 2011 06:33:59 -0500 Message-Id: <1308828839-27349-3-git-send-email-galak@kernel.crashing.org> In-Reply-To: <1308828839-27349-2-git-send-email-galak@kernel.crashing.org> References: <1308744176-24491-1-git-send-email-galak@kernel.crashing.org> <1308828839-27349-1-git-send-email-galak@kernel.crashing.org> <1308828839-27349-2-git-send-email-galak@kernel.crashing.org> Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The only reason to require a dma_ops struct is to see if it has implemented set_dma_mask. If not we can fall back to setting the mask directly. This resolves an issue with how to sequence the setting of a DMA mask for platform devices. Before we had an issue in that we have no way of setting the DMA mask before the various low level bus notifiers get called that might check it (swiotlb). So now we can do: pdev = platform_device_alloc("foobar", 0); dma_set_mask(&pdev->dev, DMA_BIT_MASK(37)); platform_device_add(pdev); And expect the right thing to happen with the bus notifiers get called via platform_device_add. Signed-off-by: Kumar Gala --- v3: Fixed commit comment to use platform_device_add() arch/powerpc/kernel/dma.c | 4 +--- 1 files changed, 1 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c index d238c08..4f0959f 100644 --- a/arch/powerpc/kernel/dma.c +++ b/arch/powerpc/kernel/dma.c @@ -161,9 +161,7 @@ int dma_set_mask(struct device *dev, u64 dma_mask) if (ppc_md.dma_set_mask) return ppc_md.dma_set_mask(dev, dma_mask); - if (unlikely(dma_ops == NULL)) - return -EIO; - if (dma_ops->set_dma_mask != NULL) + if ((dma_ops != NULL) && (dma_ops->set_dma_mask != NULL)) return dma_ops->set_dma_mask(dev, dma_mask); if (!dev->dma_mask || !dma_supported(dev, dma_mask)) return -EIO; -- 1.7.3.4