Replace two ioread32 with ioread64_lo_hi non_atomic

Philipp Hortmann philipp.g.hortmann at
Mon Apr 25 16:32:19 EDT 2022


in this patch:
[PATCH 4/5] staging: vt6655: Replace two VNSvInPortD with ioread64_lo_hi

I tried to combine two reads in one.

  	if (ww == W_MAX_TIMEOUT)
  		return false;
-	VNSvInPortD(iobase + MAC_REG_TSFCNTR, (u32 *)pqwCurrTSF);
-	VNSvInPortD(iobase + MAC_REG_TSFCNTR + 4, (u32 *)pqwCurrTSF + 1);
+	*pqwCurrTSF = ioread64_lo_hi(iobase + MAC_REG_TSFCNTR);

  	return true;

works fine on 64 bit machines but fails on 32 bit machines.

Which of the following ways is the preferred one:

#include <linux/io-64-nonatomic-lo-hi.h>
before #include "asm/io.h"
But it seems that this has never been used in a driver before?

Switch back to two reads with ioread32?

Or another proposal?

Thanks for your support.

Bye Philipp

More information about the Kernelnewbies mailing list