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intel/gm45: Refactor DDR3 read training 

Split some code in individual functions. It's the refactoring part of
a bigger change, following...

Change-Id: Ied551a011eaf22f6f8f6db0044de3634134f0b37
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/3253
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
Nico Huber 2013-05-14 11:43:03 +02:00 committed by Stefan Reinauer
parent 0da92863a7
commit 26a6435123
1 changed files with 50 additions and 32 deletions
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82
src/northbridge/intel/gm45/raminit_read_write_training.c
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@ -99,6 +99,47 @@ static int read_training_test(const int channel, const int lane,
}
return 1;
}
static void read_training_find_lower(const int channel, const int lane,
const address_bunch_t *const addresses,
read_timing_t *const lower)
{
/* Coarse search for good t. */
program_read_timing(channel, lane, lower);
while (!read_training_test(channel, lane, addresses)) {
++lower->t;
program_read_timing(channel, lane, lower);
}
/* Step back, then fine search for good p. */
if (lower->t > 0) {
--lower->t;
program_read_timing(channel, lane, lower);
while (!read_training_test(channel, lane, addresses)) {
++lower->p;
program_read_timing(channel, lane, lower);
}
}
}
static void read_training_find_upper(const int channel, const int lane,
const address_bunch_t *const addresses,
read_timing_t *const upper)
{
program_read_timing(channel, lane, upper);
if (!read_training_test(channel, lane, addresses))
die("Read training failed: limits too narrow.\n");
/* Coarse search for bad t. */
do {
++upper->t;
program_read_timing(channel, lane, upper);
} while (read_training_test(channel, lane, addresses));
/* Fine search for bad p. */
--upper->t;
program_read_timing(channel, lane, upper);
while (read_training_test(channel, lane, addresses)) {
++upper->p;
program_read_timing(channel, lane, upper);
}
}
static void read_training_per_lane(const int channel, const int lane,
const address_bunch_t *const addresses)
{
@ -106,43 +147,20 @@ static void read_training_per_lane(const int channel, const int lane,
MCHBAR32(CxRDTy_MCHBAR(channel, lane)) |= 3 << 25;
/* Search lower bound. */
/*** Search lower bound. ***/
/* Start at zero. */
lower.t = 0;
lower.p = 0;
program_read_timing(channel, lane, &lower);
/* Coarse search for good t. */
while (!read_training_test(channel, lane, addresses)) {
++lower.t;
program_read_timing(channel, lane, &lower);
}
/* Step back, then fine search for good p. */
if (lower.t > 0) {
--lower.t;
program_read_timing(channel, lane, &lower);
while (!read_training_test(channel, lane, addresses)) {
++lower.p;
program_read_timing(channel, lane, &lower);
}
}
read_training_find_lower(channel, lane, addresses, &lower);
/* Search upper bound. */
/*** Search upper bound. ***/
/* Start at lower + 1t. */
upper.t = lower.t + 1;
upper.p = lower.p;
program_read_timing(channel, lane, &upper);
if (!read_training_test(channel, lane, addresses))
die("Read training failed: limits too narrow.\n");
/* Coarse search for bad t. */
do {
++upper.t;
program_read_timing(channel, lane, &upper);
} while (read_training_test(channel, lane, addresses));
/* Fine search for bad p. */
--upper.t;
program_read_timing(channel, lane, &upper);
while (read_training_test(channel, lane, addresses)) {
++upper.p;
program_read_timing(channel, lane, &upper);
}
read_training_find_upper(channel, lane, addresses, &upper);
/* Calculate and program mean value. */
lower.p += lower.t << READ_TIMING_P_SHIFT;