Date: Tue, 25 Jan 2000 18:43:50 +0900 (JST) From: Takahashi Yoshihiro <nyan@wyvern.cc.kogakuin.ac.jp> To: luoqi@watermarkgroup.com Cc: kato@ganko.eps.nagoya-u.ac.jp, FreeBSD-current@FreeBSD.ORG, FreeBSD-hackers@FreeBSD.ORG, FreeBSD98-hackers@jp.freebsd.org, nyan@jp.freebsd.org Subject: Re: indirection in bus space Message-ID: <20000125184350C.nyan@wyvern.cc.kogakuin.ac.jp> In-Reply-To: <200001250601.BAA17157@lor.watermarkgroup.com> References: <200001250601.BAA17157@lor.watermarkgroup.com>
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In article <200001250601.BAA17157@lor.watermarkgroup.com> Luoqi Chen <luoqi@watermarkgroup.com> writes: > > I think it is difficult to implement such conversion because: > > > > - Not only bus space stuff also resource manager stuff need to > > perform such conversion. > > Why? Both bus_space_handle_t and bus_space_tag_t are supposed to be > opaque types. Resource manager needs not know the implementation details. In isa_alloc_resourcev() and isa_load_resourcev() (both new functions), it needs to store allocated resources and I/O table in bus_space_handle_pc98. > We could create a new resource type SYS_RES_IOPORT_ARRAY, and intercept > it in all isa_*_resoruce() methods. In isa_alloc_resource(), we malloc and > return a fake resource record, in which we store I386_BUS_PIO_IND as > bus tag and address of bus_space_handle_pc98 as bus handle. And in > isa_release_resource(), we first release the underlying resources stored > in the bus_space_handle_pc98 record and then free the fake resource record > itself. It should be safe as long as we don't manipulate this resource by > direct resource manager calls, which we shouldn't do anyway. > (or we should implement it at the root bus level, if pci devices in > pc98 systems also use discrete port addresses). We can't call bus_alloc_resource() directly from device drivers. Because bus_alloc_resource() is defined as the following, it can't deliver I/O table. struct resource * bus_alloc_resource(device_t dev, int type, int *rid, u_long start, u_long end, u_long count, u_int flags); If it conversion from 'bus_addr_t *' to 'u_long' and deliver to the fourth argument, we can use bus_alloc_resource(). But, it needs to perform conversions in each drivers using indirect resources. Then, only isa_alloc_resourcev() is not enough to support NS8390 based network cards and PnP devices which require to use I386_BUS_PIO_IND. So, I separate into isa_alloc_resourcev() to allocate resources and isa_load_resourcev() to store I/O table. IMHO, as IBM PC/AT and NEC PC-98 is different architecture, the bus space stuff should be implemented to different files. --- Takahashi Yoshihiro / nyan@FreeBSD.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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