[U-Boot] [PATCH 166/172] ddr: altera: Clean up rw_mgr_mem_calibrate_lfifo()

Marek Vasut
2015-07-27T20:52:09Z

Minor coding style cleanup, add kerneldoc. No functional change.

Signed-off-by: Marek Vasut <marex@denx.de>
---
drivers/ddr/altera/sequencer.c | 49 +++++++++++++++++++++++-------------------
1 file changed, 27 insertions(+), 22 deletions(-)

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;
}

/**
--
2.1.4