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nb/intel/x4x: Refactor sync DLL programming (part 2) 

Instead of counting consecutive matches (in `j`), check for a second
match directly in the control flow. Also, add some dedicated variables:

* `tap`: Keeps track of the tap value that resulted in a match and
         is eventually programmed into the hardware.

* `tap2`: Is just temporarily used to search for another edge.

Keeping `tap` sync'ed with the hardware has the benefit that we don't
need to read the programmed value back for later fixups.

Change-Id: I3ae541c39efdc695f5ca74bc757b2f009239ec93
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51903
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
This commit is contained in:
Nico Huber 2021-03-28 18:07:00 +02:00
parent a20a02e82a
commit 2bb361f0f5
1 changed files with 39 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
src/northbridge/intel/x4x/raminit_ddr23.c
View File

@ -680,7 +680,7 @@ static bool sync_dll_test_tap(unsigned int tap, uint32_t val)
return mchbar_read32(0x184) == val;
}
static void sync_dll_search_tap(uint8_t *tap, uint32_t val)
static void sync_dll_search_tap(unsigned int *tap, uint32_t val)
{
for (; *tap < sync_dll_max_taps; ++*tap)
if (sync_dll_test_tap(*tap, val))
@ -689,7 +689,7 @@ static void sync_dll_search_tap(uint8_t *tap, uint32_t val)
static void program_dll(struct sysinfo *s)
{
u8 i, j, r, reg8, clk, async = 0;
u8 i, r, reg8, clk, async = 0;
u16 reg16 = 0;
u32 reg32 = 0;
@ -842,61 +842,59 @@ static void program_dll(struct sysinfo *s)
}
/* XXX if not async mode */
unsigned int tap;
mchbar_clrbits16(0x180, 1 << 15 | 1 << 9);
mchbar_setbits8(0x180, 1 << 2);
j = 0;
for (i = 0; i < sync_dll_max_taps; i++) {
if (sync_dll_test_tap(i, 0xffffffff)) {
j++;
if (j >= 2)
for (tap = 0; tap < sync_dll_max_taps; ++tap) {
sync_dll_search_tap(&tap, 0xffffffff);
if (s->selected_timings.mem_clk == MEM_CLOCK_667MHz)
break;
if (s->selected_timings.mem_clk == MEM_CLOCK_667MHz) {
j = 2;
++tap; /* other clock speeds need a second match */
if (sync_dll_test_tap(tap, 0xffffffff))
break;
}
} else {
j = 0;
}
}
if (i == 1 || ((i == 0) && s->selected_timings.mem_clk == MEM_CLOCK_667MHz)) {
j = 0;
i++;
sync_dll_search_tap(&i, 0);
i++;
for (; i < sync_dll_max_taps; i++) {
if (sync_dll_test_tap(i, 0xffffffff)) {
j++;
if (j >= 2)
/* look for a real edge if we started with a match */
if (tap <= 1) {
unsigned int tap2 = tap + 1;
sync_dll_search_tap(&tap2, 0);
for (++tap2; tap2 < sync_dll_max_taps; ++tap2) {
sync_dll_search_tap(&tap2, 0xffffffff);
++tap2; /* we need a second match */
if (sync_dll_test_tap(tap2, 0xffffffff))
break;
}
if (tap2 < sync_dll_max_taps) {
tap = tap2;
} else {
j = 0;
}
}
if (j < 2) {
/* Using 0 instead of the original `tap` seems
inconsistent, but is what the code always did. */
sync_dll_load_tap(0);
j = 2;
tap = 0;
}
}
if (j < 2) {
if (tap >= sync_dll_max_taps) {
mchbar_clrsetbits8(0x1c8, 0x1f, 0);
tap = 0;
async = 1;
printk(BIOS_NOTICE, "HMC failed, using async mode\n");
}
mchbar_clrbits8(0x180, 1 << 7);
if ((s->spd_type == DDR3 && s->selected_timings.mem_clk == MEM_CLOCK_1066MHz)
|| (s->spd_type == DDR2 && s->selected_timings.fsb_clk == FSB_CLOCK_800MHz
&& s->selected_timings.mem_clk == MEM_CLOCK_667MHz)) {
i = mchbar_read8(0x1c8) & 0xf;
if (s->spd_type == DDR2)
i = (i + 10) % 14;
else /* DDR3 */
i = (i + 3) % 12;
sync_dll_load_tap(i);
}
if (s->spd_type == DDR3 && s->selected_timings.mem_clk == MEM_CLOCK_1066MHz)
sync_dll_load_tap((tap + 3) % 12);
if (s->spd_type == DDR2 &&
s->selected_timings.fsb_clk == FSB_CLOCK_800MHz &&
s->selected_timings.mem_clk == MEM_CLOCK_667MHz)
sync_dll_load_tap((tap + 10) % 14);
switch (s->selected_timings.mem_clk) {
case MEM_CLOCK_667MHz: