Date: Tue, 05 Sep 2006 12:31:20 -0600 From: Scott Long <scottl@samsco.org> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: freebsd-current@freebsd.org, freebsd-drivers@freebsd.org, freebsd-arch@freebsd.org Subject: Re: bus_get_dma_tag now necessary for drivers using bus_dma Message-ID: <44FDC278.3050902@samsco.org> In-Reply-To: <14026.1157478288@critter.freebsd.dk> References: <14026.1157478288@critter.freebsd.dk>
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Poul-Henning Kamp wrote: > In message <20060905173334.GH9421@funkthat.com>, John-Mark Gurney writes: > > >>This means that for each call to bus_dma_tag_create, instead of passing >>a NULL pointer, you should call bus_get_dma_tag(yourdev) and use that >>as the parent tag. I committed some example code to various drivers, >>such as ahc, ata, em, and ohci. > > > If there are never any exeptions to this requirement, why not > pass "yourdev" and have the magic hidden, rather than add 17 > ritual characters to the API ? > Drivers can have their own multi-level tag heirarchy. You'd have to create a new bus_dma_tag_create() variant that expected a device_t instead of a bus_dma_tag_t. This might be a good idea. Scott
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