Sergei Shtylyov wrote:

quoted

+	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, 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.

-Scott