Date: Wed, 26 Jan 2000 14:38:36 -0700 From: Warner Losh <imp@village.org> To: Jeroen Ruigrok/Asmodai <asmodai@wxs.nl> Cc: "Matthew N. Dodd" <winter@jurai.net>, new-bus@FreeBSD.ORG Subject: Re: newbus from a documentation view Message-ID: <200001262138.OAA02463@harmony.village.org> In-Reply-To: Your message of "Wed, 26 Jan 2000 18:23:10 %2B0100." <20000126182309.H290@daemon.ninth-circle.org> References: <20000126182309.H290@daemon.ninth-circle.org> <20000126094020.G290@daemon.ninth-circle.org> <Pine.BSF.4.21.0001260341430.462-100000@sasami.jurai.net>
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In message <20000126182309.H290@daemon.ninth-circle.org> Jeroen Ruigrok/Asmodai writes: : >> machine/bus_memio.h <also in alpha and i386 version> : >> I see that this one is basically an empty header, deprecated in : >> usage? : : I see we #define bus_memio_h in machine/bus.h, so basically all drivers : including machine/bus_memio.h and bus_pio.h are kinda out of synch with : newbus/busspace? : : >> machine/bus_pio.h <also in alpha and i386 version> : >> I see that this one is also an empty header, also deprecated in : >> usage? : : See above. The way that Justin had intended it is as follows. If the device hardware supported I/O mapping, then you'd include <machine/bus_pio.h> in your driver. It would do what was needed to bring in support for progammed I/O. Likewise with <machine/bus_mem.h>. This would allow the bus_space_read_1, et al, to be highly optimized for devices that could optimize them. He told me in private conversations that this made a big difference in the performance he was seeing in the ahc driver at the time. I don't know how big big is, however. I know there was also optimizations in the api to bus_space_dma to allow things to work better on specialized hardware. I changed this a little to default to using both memory and progammed I/O if neither was included to be more compatible with NetBSD and newconfig. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-new-bus" in the body of the message
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