Nico Huber (nico.huber@secunet.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3256
-gerrit
commit 982206f2941906f2aef139179b3ae6d4169fe5ae Author: Nico Huber nico.huber@secunet.com Date: Tue May 14 12:15:05 2013 +0200
intel/gm45: Handle overflows during DDR3 write training
We halted the machine on any overflow during the write training. However, overflows during the search for a good to bad edge are non-fatal, and should be ignored.
Change-Id: I45ccbabc214e208974039246d806b0d2ca2fdc03 Signed-off-by: Nico Huber nico.huber@secunet.com --- .../intel/gm45/raminit_read_write_training.c | 91 +++++++++++++++------- 1 file changed, 63 insertions(+), 28 deletions(-)
diff --git a/src/northbridge/intel/gm45/raminit_read_write_training.c b/src/northbridge/intel/gm45/raminit_read_write_training.c index 72c83a7..65e16a3 100644 --- a/src/northbridge/intel/gm45/raminit_read_write_training.c +++ b/src/northbridge/intel/gm45/raminit_read_write_training.c @@ -342,7 +342,7 @@ typedef struct { const int t_bound; int p; } write_timing_t; -static void normalize_write_timing(write_timing_t *const timing) +static int normalize_write_timing(write_timing_t *const timing) { while (timing->p >= WRITE_TIMING_P_BOUND) { timing->t++; @@ -360,16 +360,31 @@ static void normalize_write_timing(write_timing_t *const timing) timing->f--; timing->t += timing->t_bound; } - if ((timing->f < 0) || (timing->f >= WRITE_TIMING_F_BOUND)) - die("Timing under-/overflow during write training.\n"); + if (timing->f < 0) { + printk(BIOS_WARNING, + "Timing underflow during write training.\n"); + timing->f = 0; + timing->t = 0; + timing->p = 0; + return -1; + } else if (timing->f >= WRITE_TIMING_F_BOUND) { + printk(BIOS_WARNING, + "Timing overflow during write training.\n"); + timing->f = WRITE_TIMING_F_BOUND - 1; + timing->t = timing->t_bound - 1; + timing->p = WRITE_TIMING_P_BOUND - 1; + return -1; + } + return 0; } -static void program_write_timing(const int ch, const int group, - write_timing_t *const timing, int memclk1067) +static int program_write_timing(const int ch, const int group, + write_timing_t *const timing, int memclk1067) { /* MEM_CLOCK_1067MT? X lower/upper */ const u32 d_bounds[2][2] = { { 1, 6 }, { 2, 9 } };
- normalize_write_timing(timing); + if (normalize_write_timing(timing) < 0) + return -1;
const int f = timing->f; const int t = timing->t; @@ -385,6 +400,8 @@ static void program_write_timing(const int ch, const int group, reg &= ~CxWRTy_D_MASK; reg |= CxWRTy_T(t) | CxWRTy_P(p) | CxWRTy_F(f) | d; MCHBAR32(CxWRTy_MCHBAR(ch, group)) = reg; + + return 0; } /* Returns 1 on success, 0 on failure. */ static int write_training_test(const address_bunch_t *const addresses, @@ -426,45 +443,61 @@ _bad_timing_out:
return ret; } -static void write_training_find_lower(const int ch, const int group, - const address_bunch_t *const addresses, - const u32 masks[][2], const int memclk1067, - write_timing_t *const lower) +static int write_training_find_lower(const int ch, const int group, + const address_bunch_t *const addresses, + const u32 masks[][2], const int memclk1067, + write_timing_t *const lower) { program_write_timing(ch, group, lower, memclk1067); /* Coarse search for good t. */ while (!write_training_test(addresses, masks[group])) { ++lower->t; - program_write_timing(ch, group, lower, memclk1067); + if (program_write_timing(ch, group, lower, memclk1067) < 0) + return -1; } - /* Fine search for good p. */ + /* Step back, then fine search for good p. */ + if ((lower->f <= 0) && (lower->t <= 0)) + /* Can't step back, zero is good. */ + return 0; + --lower->t; program_write_timing(ch, group, lower, memclk1067); while (!write_training_test(addresses, masks[group])) { ++lower->p; - program_write_timing(ch, group, lower, memclk1067); + if (program_write_timing(ch, group, lower, memclk1067) < 0) + return -1; } + + return 0; } -static void write_training_find_upper(const int ch, const int group, - const address_bunch_t *const addresses, - const u32 masks[][2], const int memclk1067, - write_timing_t *const upper) +static int write_training_find_upper(const int ch, const int group, + const address_bunch_t *const addresses, + const u32 masks[][2], const int memclk1067, + write_timing_t *const upper) { - program_write_timing(ch, group, upper, memclk1067); - if (!write_training_test(addresses, masks[group])) - die("Write training failed; limits too narrow.\n"); - /* Coarse search for good t. */ + if (program_write_timing(ch, group, upper, memclk1067) < 0) + return -1; + if (!write_training_test(addresses, masks[group])) { + printk(BIOS_WARNING, + "Write training failure; limits too narrow.\n"); + return -1; + } + /* Coarse search for bad t. */ while (write_training_test(addresses, masks[group])) { ++upper->t; - program_write_timing(ch, group, upper, memclk1067); + if (program_write_timing(ch, group, upper, memclk1067) < 0) + return -1; } - /* Fine search for good p. */ + /* Fine search for bad p. */ --upper->t; program_write_timing(ch, group, upper, memclk1067); while (write_training_test(addresses, masks[group])) { ++upper->p; - program_write_timing(ch, group, upper, memclk1067); + if (program_write_timing(ch, group, upper, memclk1067) < 0) + return -1; } + + return 0; } static void write_training_per_group(const int ch, const int group, const address_bunch_t *const addresses, @@ -482,8 +515,9 @@ static void write_training_per_group(const int ch, const int group, lower.p = (reg >> 8) & 0x7; lower.f = ((reg >> 2) & 0x3) - 1;
- write_training_find_lower(ch, group, addresses, - masks, memclk1067, &lower); + if (write_training_find_lower(ch, group, addresses, + masks, memclk1067, &lower) < 0) + die("Write training failure: lower bound.\n");
/*** Search upper bound. ***/
@@ -492,8 +526,9 @@ static void write_training_per_group(const int ch, const int group, upper.p = lower.p; upper.f = lower.f;
- write_training_find_upper(ch, group, addresses, - masks, memclk1067, &upper); + if (write_training_find_upper(ch, group, addresses, + masks, memclk1067, &upper) < 0) + printk(BIOS_WARNING, "Write training failure: upper bound.\n");
/*** Calculate and program mean value. ***/