pata_pdc2027x: Use 64-bit timekeeping

Function pdc_detect_pll_input_clock uses 'struct timeval'
to measure start and end times, used to compute the pll_clock value.
'struct timeval' on 32-bit systems will have its tv_sec field
overflow in year 2038 and beyond. This patch uses 'ktime_t'
(which uses 64 bits for seconds) for start and end times instead.

Suggested-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Tina Ruchandani <[e-mail]>
Reviewed-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Tejun Heo <[e-mail]>

drivers/ata/pata_pdc2027x.c

···
 #include <linux/blkdev.h>
 #include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/ktime.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_cmnd.h>
···
 	void __iomem *mmio_base = host->iomap[PDC_MMIO_BAR];
 	u32 scr;
 	long start_count, end_count;
-	struct timeval start_time, end_time;
+	ktime_t start_time, end_time;
 	long pll_clock, usec_elapsed;
 
 	/* Start the test mode */
···
 
 	/* Read current counter value */
 	start_count = pdc_read_counter(host);
-	do_gettimeofday(&start_time);
+	start_time = ktime_get();
 
 	/* Let the counter run for 100 ms. */
 	mdelay(100);
 
 	/* Read the counter values again */
 	end_count = pdc_read_counter(host);
-	do_gettimeofday(&end_time);
+	end_time = ktime_get();
 
 	/* Stop the test mode */
 	scr = ioread32(mmio_base + PDC_SYS_CTL);
···
 	ioread32(mmio_base + PDC_SYS_CTL); /* flush */
 
 	/* calculate the input clock in Hz */
-	usec_elapsed = (end_time.tv_sec - start_time.tv_sec) * 1000000 +
-		(end_time.tv_usec - start_time.tv_usec);
+	usec_elapsed = (long) ktime_us_delta(end_time, start_time);
 
 	pll_clock = ((start_count - end_count) & 0x3fffffff) / 100 *
 		(100000000 / usec_elapsed);