From c984278a66f0b785835e058fc4e3e9731c5fa94f Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Tue, 21 Jul 2015 06:18:57 +0200 Subject: ddr: altera: Clean up rw_mgr_mem_calibrate_lfifo() Minor coding style cleanup, add kerneldoc. No functional change. Signed-off-by: Marek Vasut --- drivers/ddr/altera/sequencer.c | 49 +++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 22 deletions(-) (limited to 'drivers') diff --git a/drivers/ddr/altera/sequencer.c b/drivers/ddr/altera/sequencer.c index 2baf77d..eb0e8cf 100644 --- a/drivers/ddr/altera/sequencer.c +++ b/drivers/ddr/altera/sequencer.c @@ -2818,60 +2818,65 @@ static int rw_mgr_mem_calibrate_vfifo_end(const u32 rw_group, return ret; } -/* Calibrate LFIFO to find smallest read latency */ +/** + * rw_mgr_mem_calibrate_lfifo() - Minimize latency + * + * Stage 4: Minimize latency. + * + * This function implements UniPHY calibration Stage 4, as explained in + * detail in Altera EMI_RM 2015.05.04 , "UniPHY Calibration Stages". + * Calibrate LFIFO to find smallest read latency. + */ static uint32_t rw_mgr_mem_calibrate_lfifo(void) { - uint32_t found_one; + int found_one = 0; debug("%s:%d\n", __func__, __LINE__); - /* update info for sims */ + /* Update info for sims. */ reg_file_set_stage(CAL_STAGE_LFIFO); reg_file_set_sub_stage(CAL_SUBSTAGE_READ_LATENCY); /* Load up the patterns used by read calibration for all ranks */ rw_mgr_mem_calibrate_read_load_patterns(0, 1); - found_one = 0; do { writel(gbl->curr_read_lat, &phy_mgr_cfg->phy_rlat); debug_cond(DLEVEL == 2, "%s:%d lfifo: read_lat=%u", __func__, __LINE__, gbl->curr_read_lat); - if (!rw_mgr_mem_calibrate_read_test_all_ranks(0, - NUM_READ_TESTS, - PASS_ALL_BITS, - 1)) { + if (!rw_mgr_mem_calibrate_read_test_all_ranks(0, NUM_READ_TESTS, + PASS_ALL_BITS, 1)) break; - } found_one = 1; - /* reduce read latency and see if things are working */ - /* correctly */ + /* + * Reduce read latency and see if things are + * working correctly. + */ gbl->curr_read_lat--; } while (gbl->curr_read_lat > 0); - /* reset the fifos to get pointers to known state */ - + /* Reset the fifos to get pointers to known state. */ writel(0, &phy_mgr_cmd->fifo_reset); if (found_one) { - /* add a fudge factor to the read latency that was determined */ + /* Add a fudge factor to the read latency that was determined */ gbl->curr_read_lat += 2; writel(gbl->curr_read_lat, &phy_mgr_cfg->phy_rlat); - debug_cond(DLEVEL == 2, "%s:%d lfifo: success: using \ - read_lat=%u\n", __func__, __LINE__, - gbl->curr_read_lat); - return 1; + debug_cond(DLEVEL == 2, + "%s:%d lfifo: success: using read_lat=%u\n", + __func__, __LINE__, gbl->curr_read_lat); } else { set_failing_group_stage(0xff, CAL_STAGE_LFIFO, CAL_SUBSTAGE_READ_LATENCY); - debug_cond(DLEVEL == 2, "%s:%d lfifo: failed at initial \ - read_lat=%u\n", __func__, __LINE__, - gbl->curr_read_lat); - return 0; + debug_cond(DLEVEL == 2, + "%s:%d lfifo: failed at initial read_lat=%u\n", + __func__, __LINE__, gbl->curr_read_lat); } + + return found_one; } /** -- cgit v1.1