From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felipe Balbi Subject: Re: [PATCH RFC] usb: musb: fail unaligned DMA transfers on v1.8 and above Date: Fri, 5 Nov 2010 14:26:31 +0200 Message-ID: <20101105122631.GA1952@legolas.emea.dhcp.ti.com> References: <1288502759-18618-1-git-send-email-gadiyar@ti.com> Reply-To: balbi@ti.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Return-path: Received: from bear.ext.ti.com ([192.94.94.41]:34861 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751953Ab0KEM0P (ORCPT ); Fri, 5 Nov 2010 08:26:15 -0400 Content-Disposition: inline In-Reply-To: <1288502759-18618-1-git-send-email-gadiyar@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Gadiyar, Anand" Cc: "linux-usb@vger.kernel.org" , "linux-omap@vger.kernel.org" , Greg Kroah-Hartman , "Balbi, Felipe" , Ming Lei , "Gupta, Ajay Kumar" , Mike Frysinger On Sun, Oct 31, 2010 at 12:25:59AM -0500, Gadiyar, Anand wrote: >The Inventra DMA engine in version 1.8 and later of the MUSB >controller cannot handle DMA addresses that are not aligned >to a 4 byte boundary. It ends up ignoring the last two bits >programmed in the DMA_ADDR register. This is a deliberate >design change in the controller and is documented in the >programming guide. > >Earlier versions of the controller could handle these >accesses just fine. > >Fail dma_channel_program if we see an unaligned address when >using the newer controllers, so that the caller can carry out >the transfer using PIO mode. >(Current callers already have this backup path in place). > >Signed-off-by: Anand Gadiyar >Cc: Felipe Balbi >Cc: Ming Lei >Cc: Ajay Kumar Gupta >Cc: Mike Frysinger please fix comment from Sergei and resend without RFC. -- balbi