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authorMichael Ellerman <michael@ellerman.id.au>2007-10-15 19:34:36 +1000
committerJeff Garzik <jeff@garzik.org>2007-10-15 14:29:49 -0400
commit83f34df4e7c8794a5a81ede663fe184f4201308a (patch)
treec109c113ee02c5d656cd1b211ba2bc67d5dfd270 /Documentation/block
parent0f18e719dc0d36ad91fe94b0b3dd08fdcdd2faa2 (diff)
Add dcr_host_t.base in dcr_read()/dcr_write()
Now that all users of dcr_read()/dcr_write() add the dcr_host_t.base, we can save them the trouble and do it in dcr_read()/dcr_write(). As some background to why we just went through all this jiggery-pokery, benh sayeth: Initially the goal of the dcr_read/dcr_write routines was to operate like mfdcr/mtdcr which take absolute DCR numbers. The reason is that on 4xx hardware, indirect DCR access is a pain (goes through a table of instructions) and it's useful to have the compiler resolve an absolute DCR inline. We decided that wasn't worth the API bastardisation since most places where absolute DCR values are used are low level 4xx-only code which may as well continue using mfdcr/mtdcr, while the new API is designed for device "instances" that can exist on 4xx and Axon type platforms and may be located at variable DCR offsets. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Jeff Garzik <jeff@garzik.org>
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