Messages in this thread | | | Date | Wed, 25 Jul 2007 23:16:12 +0400 | From | Sergei Shtylyov <> | Subject | Re: [PATCH 1/2] [IDE] Platform IDE driver (was: MMIO IDE driver) |
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Hello.
Scott Wood wrote:
>>> + hwif->hw.io_ports[IDE_DATA_OFFSET] = port; >>> + >>> + port += (1 << pdata->ioport_shift); >>> + for (i = IDE_ERROR_OFFSET; i <= IDE_STATUS_OFFSET; >>> + i++, port += (1 << pdata->ioport_shift)) >> >> >> >> Looks like shift doesn't buy as anything, why not just use stride?
> It doesn't buy us anything in here, but it's conceivable that someone > may want to write a driver that uses a shift in the I/O accessor rather > than an array of port offsets,
It wouldn't be IDE driver then, and neither it would be libata which also does this another way this (despite pata_platform uses shifts too -- not in the accessors, so no speed loss).
> and it's easier to convert a shift to a stride than the other way around > (not all architectures have an > equivalent of the cntlzw innstruction, and shift makes it clear that the > stride must be power-of-two). Plus, using shift is consistent with what > we do on ns16550.
Why the heck should we care about the UART code taling about IDE?! So, let me consider your argument purely speculative and invalid. ;-)
> -Scott
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