From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timur Tabi Subject: Re: [PATCH] [v6] net: emac: emac gigabit ethernet controller driver Date: Wed, 29 Jun 2016 10:46:23 -0500 Message-ID: <5773ED4F.4050401@codeaurora.org> References: <1466812008-26686-1-git-send-email-timur@codeaurora.org> <5679359.84lXZytcOR@wuerfel> <5773E503.3070404@codeaurora.org> <3914163.aNiIdzedWT@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3914163.aNiIdzedWT@wuerfel> Sender: linux-arm-msm-owner@vger.kernel.org To: Arnd Bergmann Cc: netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, sdharia@codeaurora.org, shankerd@codeaurora.org, vikrams@codeaurora.org, cov@codeaurora.org, gavidov@codeaurora.org, robh+dt@kernel.org, andrew@lunn.ch, bjorn.andersson@linaro.org, mlangsdo@redhat.com, jcm@redhat.com, agross@codeaurora.org, davem@davemloft.net, f.fainelli@gmail.com, catalin.marinas@arm.com List-Id: devicetree@vger.kernel.org Arnd Bergmann wrote: > Usually drivers try 64-bit mask and 32-bit masks, and the 32 bit > mask is practically guaranteed to succeed. Sure, but in theory, my for-loop is correct, right? Wouldn't there be some value in setting a 36-bit or 40-bit DMA mask if it works? We have a platform where memory starts at a 40-bit address, so some devices have a 44-bit address bus. If a 64-bit mask doesn't work, then a 32-bit mask certainly wont. > Platforms will also allow allow the driver to set a mask that > is larger than what the bus supports, as long as all RAM is > reachable by the bus. And that check (like all others) is made in the dma_set_mask call? -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation collaborative project.