The s3cmci driver uses the host->pio_ptr field to
point to the current position into the buffer for data
transfer. During the transfers it does the following:
while (fifo_words--)
*(host->pio_ptr++) = readl(from_ptr);
This is inefficent, as host->pio_ptr is not used in any
other part of the transfer but the compiler emits code
which does the following: