Commit 75a23850 authored by Finn Thain's avatar Finn Thain Committed by Geert Uytterhoeven
Browse files

m68k/mac: Fix compiler warning in via_read_time() 



The algorithm described in the comment compares two reads from the RTC but
the code actually reads once and compares the result to an uninitialized
value. This causes the compiler to warn, "last_result maybe used
uninitialized". Make the code match the comment, fix the warning and
perhaps improve reliability. Tested on a Quadra 700.

Signed-off-by: default avatarFinn Thain <fthain@telegraphics.com.au>
Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent d996e9dc

arch/m68k/mac/misc.c

+23 −17
Original line number Diff line number Diff line
@@ -307,32 +307,38 @@ static long via_read_time(void) 
		__u8 cdata[4];

		long idata;

	} result, last_result;

	int	ct;

	int count = 1;



	via_pram_command(0x81, &last_result.cdata[3]);

	via_pram_command(0x85, &last_result.cdata[2]);

	via_pram_command(0x89, &last_result.cdata[1]);

	via_pram_command(0x8D, &last_result.cdata[0]);



	/*

	 * The NetBSD guys say to loop until you get the same reading

	 * twice in a row.

	 */



	ct = 0;

	do {

		if (++ct > 10) {

			printk("via_read_time: couldn't get valid time, "

			       "last read = 0x%08lx and 0x%08lx\n",

			       last_result.idata, result.idata);

			break;

		}



		last_result.idata = result.idata;

		result.idata = 0;



	while (1) {

		via_pram_command(0x81, &result.cdata[3]);

		via_pram_command(0x85, &result.cdata[2]);

		via_pram_command(0x89, &result.cdata[1]);

		via_pram_command(0x8D, &result.cdata[0]);

	} while (result.idata != last_result.idata);



		if (result.idata == last_result.idata)

			return result.idata - RTC_OFFSET;



		if (++count > 10)

			break;



		last_result.idata = result.idata;

	}



	pr_err("via_read_time: failed to read a stable value; "

	       "got 0x%08lx then 0x%08lx\n",

	       last_result.idata, result.idata);



	return 0;

}



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