From mboxrd@z Thu Jan 1 00:00:00 1970 From: srinivas.kandagatla@linaro.org (Srinivas Kandagatla) Date: Thu, 4 Jan 2018 09:25:24 +0000 Subject: [RESEND PATCH v2 14/15] ASoC: qcom: apq8096: Add db820c machine driver In-Reply-To: <20180103194151.GA21040@codeaurora.org> References: <20171214173402.19074-1-srinivas.kandagatla@linaro.org> <20171214173402.19074-15-srinivas.kandagatla@linaro.org> <4db358ab-3171-bb08-ca26-ec9bf282e8d4@linaro.org> <20180103194151.GA21040@codeaurora.org> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/01/18 19:41, Stephen Boyd wrote: >>>> + ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32)); >>> Why do we need to do this? Can you add some sort of comment in the code >>> about why? >> Even though dsp supports 64 bit addresses, but the sid sits at >> offset of 32, which brings this restriction of supporting only 32 >> bit iova. >> > Doesn't the dsp have an iommu in place to make the address > translation from 64 to 32 bits transparent? I thought this was > what dma-ranges and iommu binding was for, but I'm not well > versed on all the details here. Thanks for reminding, dma-ranges would work too, I will give that a go in next version. --srini