From afb3eb84b843c877165c75d64b3f2065e9dc83b1 Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Sat, 18 Jul 2015 19:18:06 +0200 Subject: [PATCH] ddr: altera: Clean up rw_mgr_mem_calibrate_vfifo_center() part 5 Factor out the get_window_mid_index() for finding the best DQ window centering. This is again code common to two stages, so pull it out. Signed-off-by: Marek Vasut --- drivers/ddr/altera/sequencer.c | 90 +++++++++++++++++----------------- 1 file changed, 44 insertions(+), 46 deletions(-) diff --git a/drivers/ddr/altera/sequencer.c b/drivers/ddr/altera/sequencer.c index 3db226d7a8..d6b96f4caa 100644 --- a/drivers/ddr/altera/sequencer.c +++ b/drivers/ddr/altera/sequencer.c @@ -2073,6 +2073,48 @@ static int search_right_edge(const int write, const int rank_bgn, return 0; } +/** + * get_window_mid_index() - Find the best middle setting of DQ/DQS phase + * @write: Perform read (Stage 2) or write (Stage 3) calibration + * @left_edge: Left edge of the DQ/DQS phase + * @right_edge: Right edge of the DQ/DQS phase + * @mid_min: Best DQ/DQS phase middle setting + * + * Find index and value of the middle of the DQ/DQS working phase. + */ +static int get_window_mid_index(const int write, int *left_edge, + int *right_edge, int *mid_min) +{ + const u32 per_dqs = write ? RW_MGR_MEM_DQ_PER_WRITE_DQS : + RW_MGR_MEM_DQ_PER_READ_DQS; + int i, mid, min_index; + + /* Find middle of window for each DQ bit */ + *mid_min = left_edge[0] - right_edge[0]; + min_index = 0; + for (i = 1; i < per_dqs; i++) { + mid = left_edge[i] - right_edge[i]; + if (mid < *mid_min) { + *mid_min = mid; + min_index = i; + } + } + + /* + * -mid_min/2 represents the amount that we need to move DQS. + * If mid_min is odd and positive we'll need to add one to make + * sure the rounding in further calculations is correct (always + * bias to the right), so just add 1 for all positive values. + */ + if (*mid_min > 0) + (*mid_min)++; + *mid_min = *mid_min / 2; + + debug_cond(DLEVEL == 1, "%s:%d vfifo_center: *mid_min=%d (index=%u)\n", + __func__, __LINE__, *mid_min, min_index); + return min_index; +} + /* per-bit deskew DQ and center */ static uint32_t rw_mgr_mem_calibrate_vfifo_center(uint32_t rank_bgn, uint32_t write_group, uint32_t read_group, uint32_t test_bgn, @@ -2155,30 +2197,7 @@ static uint32_t rw_mgr_mem_calibrate_vfifo_center(uint32_t rank_bgn, return 0; } - /* Find middle of window for each DQ bit */ - mid_min = left_edge[0] - right_edge[0]; - min_index = 0; - for (i = 1; i < RW_MGR_MEM_DQ_PER_READ_DQS; i++) { - mid = left_edge[i] - right_edge[i]; - if (mid < mid_min) { - mid_min = mid; - min_index = i; - } - } - - /* - * -mid_min/2 represents the amount that we need to move DQS. - * If mid_min is odd and positive we'll need to add one to - * make sure the rounding in further calculations is correct - * (always bias to the right), so just add 1 for all positive values. - */ - if (mid_min > 0) - mid_min++; - - mid_min = mid_min / 2; - - debug_cond(DLEVEL == 1, "%s:%d vfifo_center: mid_min=%d (index=%u)\n", - __func__, __LINE__, mid_min, min_index); + min_index = get_window_mid_index(0, left_edge, right_edge, &mid_min); /* Determine the amount we can change DQS (which is -mid_min) */ orig_mid_min = mid_min; @@ -2888,28 +2907,7 @@ static uint32_t rw_mgr_mem_calibrate_writes_center(uint32_t rank_bgn, return 0; } - /* Find middle of window for each DQ bit */ - mid_min = left_edge[0] - right_edge[0]; - min_index = 0; - for (i = 1; i < RW_MGR_MEM_DQ_PER_WRITE_DQS; i++) { - mid = left_edge[i] - right_edge[i]; - if (mid < mid_min) { - mid_min = mid; - min_index = i; - } - } - - /* - * -mid_min/2 represents the amount that we need to move DQS. - * If mid_min is odd and positive we'll need to add one to - * make sure the rounding in further calculations is correct - * (always bias to the right), so just add 1 for all positive values. - */ - if (mid_min > 0) - mid_min++; - mid_min = mid_min / 2; - debug_cond(DLEVEL == 1, "%s:%d write_center: mid_min=%d\n", __func__, - __LINE__, mid_min); + min_index = get_window_mid_index(1, left_edge, right_edge, &mid_min); /* Determine the amount we can change DQS (which is -mid_min) */ orig_mid_min = mid_min; -- 2.25.1