mips: mt76x8: ddr_cal: Correct dqs_find_min/max implementations
The current implementations have some issues detecting the correct
values:
dqs_find_max() will return "last passing fieldval + 1" instead of
"last passing fieldval". Also it will return "maxval + 1" in the
case that all fieldvals are tested valid (without error).
dqs_find_min() will not test the "lowest" value because of using ">"
instead of ">=".
This patch now rewrites these functions to fix those issues. Also,
this patch uses the same approach of a for loop in both functions making
it easier to read and maintain.
Since the variables are integers now, we can use min()/max(), which
handles the wrap around case for fieldval=0: return (0 - 1).
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Weijie Gao <weijie.gao@mediatek.com>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Reviewed-by: Weijie Gao <weijie.gao@mediatek.com>
diff --git a/arch/mips/mach-mtmips/ddr_cal.c b/arch/mips/mach-mtmips/ddr_cal.c
index 80a058d..71a53c3 100644
--- a/arch/mips/mach-mtmips/ddr_cal.c
+++ b/arch/mips/mach-mtmips/ddr_cal.c
@@ -74,39 +74,31 @@
static inline int dqs_find_max(void __iomem *memc, u32 memsize, int initval,
int maxval, int shift, u32 regval)
{
- int fieldval = initval;
+ int fieldval;
u32 dqsval;
- do {
+ for (fieldval = initval; fieldval <= maxval; fieldval++) {
dqsval = regval | (fieldval << shift);
-
if (dqs_test_error(memc, memsize, dqsval, 3))
- break;
+ return max(fieldval - 1, initval);
+ }
- fieldval++;
- } while (fieldval <= maxval);
-
- return fieldval;
+ return maxval;
}
static inline int dqs_find_min(void __iomem *memc, u32 memsize, int initval,
int minval, int shift, u32 regval)
{
- int fieldval = initval;
+ int fieldval;
u32 dqsval;
- while (fieldval > minval) {
+ for (fieldval = initval; fieldval >= minval; fieldval--) {
dqsval = regval | (fieldval << shift);
-
- if (dqs_test_error(memc, memsize, dqsval, 1)) {
- fieldval++;
- break;
- }
-
- fieldval--;
+ if (dqs_test_error(memc, memsize, dqsval, 1))
+ return min(fieldval + 1, initval);
}
- return fieldval;
+ return minval;
}
void ddr_calibrate(void __iomem *memc, u32 memsize, u32 bw)