static void wait_us(unsigned long us)
 {
        unsigned long start = OSCR;
-       us *= OSCR_CLK_FREQ;
+       us = DIV_ROUND_UP(us * OSCR_CLK_FREQ, 1000);
 
        while (get_delta(start) < us) {
                /* do nothing */
        if(!event)
                return 0xff000000;
        else if(event & (NDSR_CS0_CMDD | NDSR_CS0_BBD))
-               timeout = CONFIG_SYS_NAND_PROG_ERASE_TO * OSCR_CLK_FREQ;
+               timeout = DIV_ROUND_UP(CONFIG_SYS_NAND_PROG_ERASE_TO
+                                       * OSCR_CLK_FREQ, 1000);
        else
-               timeout = CONFIG_SYS_NAND_OTHER_TO * OSCR_CLK_FREQ;
+               timeout = DIV_ROUND_UP(CONFIG_SYS_NAND_OTHER_TO
+                                       * OSCR_CLK_FREQ, 1000);
 
        while(1) {
                ndsr = NDSR;
 
 static void wait_us(unsigned long us)
 {
        unsigned long start = OSCR;
-       us *= OSCR_CLK_FREQ;
+       us = DIV_ROUND_UP(us * OSCR_CLK_FREQ, 1000);
 
        while (get_delta(start) < us) {
                /* do nothing */
        if(!event)
                return 0xff000000;
        else if(event & (NDSR_CS0_CMDD | NDSR_CS0_BBD))
-               timeout = CONFIG_SYS_NAND_PROG_ERASE_TO * OSCR_CLK_FREQ;
+               timeout = DIV_ROUND_UP(CONFIG_SYS_NAND_PROG_ERASE_TO
+                                       * OSCR_CLK_FREQ, 1000);
        else
-               timeout = CONFIG_SYS_NAND_OTHER_TO * OSCR_CLK_FREQ;
+               timeout = DIV_ROUND_UP(CONFIG_SYS_NAND_OTHER_TO
+                                       * OSCR_CLK_FREQ, 1000);
 
        while(1) {
                ndsr = NDSR;
 
 #define OMCR10         __REG(0x40A000D8)  /* OS Match Control Register 10 */
 #define OMCR11         __REG(0x40A000DC)  /* OS Match Control Register 11 */
 
-#define OSCR_CLK_FREQ   3.250             /* MHz */
+#define OSCR_CLK_FREQ   3250              /* kHz = 3.25 MHz */
 #endif /* CONFIG_CPU_MONAHANS */
 
 #define OSSR_M4                (1 << 4)        /* Match status channel 4 */