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ddr: altera: Clean up set_rank_and_odt_mask() part 3

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Clean up comments and add kerneldoc.

Signed-off-by: Marek Vasut <marex@denx.de>
This commit is contained in:
Marek Vasut 2015-07-20 08:15:57 +02:00
parent 287cdf6be7
commit 080bf64ef1
1 changed files with 20 additions and 14 deletions
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34
drivers/ddr/altera/sequencer.c
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@ -154,6 +154,13 @@ static void phy_mgr_initialize(void)
param->dm_correct_mask = (1 << ratio) - 1;
}
/**
* set_rank_and_odt_mask() - Set Rank and ODT mask
* @rank: Rank mask
* @odt_mode: ODT mode, OFF or READ_WRITE
*
* Set Rank and ODT mask (On-Die Termination).
*/
static void set_rank_and_odt_mask(const u32 rank, const u32 odt_mode)
{
u32 odt_mask_0 = 0;
@ -172,14 +179,15 @@ static void set_rank_and_odt_mask(const u32 rank, const u32 odt_mode)
break;
case 2: /* 2 Ranks */
if (RW_MGR_MEM_NUMBER_OF_CS_PER_DIMM == 1) {
/* - Dual-Slot , Single-Rank
* (1 chip-select per DIMM)
* OR
* - RDIMM, 4 total CS (2 CS per DIMM)
* means 2 DIMM
* Since MEM_NUMBER_OF_RANKS is 2 they are
* both single rank
* with 2 CS each (special for RDIMM)
/*
* - Dual-Slot , Single-Rank (1 CS per DIMM)
* OR
* - RDIMM, 4 total CS (2 CS per DIMM, 2 DIMM)
*
* Since MEM_NUMBER_OF_RANKS is 2, they
* are both single rank with 2 CS each
* (special for RDIMM).
*
* Read: Turn on ODT on the opposite rank
* Write: Turn on ODT on all ranks
*/
@ -187,10 +195,10 @@ static void set_rank_and_odt_mask(const u32 rank, const u32 odt_mode)
odt_mask_1 = 0x3;
} else {
/*
* USER - Single-Slot , Dual-rank DIMMs
* (2 chip-selects per DIMM)
* USER Read: Turn on ODT off on all ranks
* USER Write: Turn on ODT on active rank
* - Single-Slot , Dual-Rank (2 CS per DIMM)
*
* Read: Turn on ODT off on all ranks
* Write: Turn on ODT on active rank
*/
odt_mask_0 = 0x0;
odt_mask_1 = 0x3 & (1 << rank);
@ -199,7 +207,6 @@ static void set_rank_and_odt_mask(const u32 rank, const u32 odt_mode)
case 4: /* 4 Ranks */
/* Read:
* ----------+-----------------------+
* | |
* | ODT |
* Read From +-----------------------+
* Rank | 3 | 2 | 1 | 0 |
@ -212,7 +219,6 @@ static void set_rank_and_odt_mask(const u32 rank, const u32 odt_mode)
*
* Write:
* ----------+-----------------------+
* | |
* | ODT |
* Write To +-----------------------+
* Rank | 3 | 2 | 1 | 0 |