From 7963f58cbf3a722c93f946c80a12f185b86dc45c Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 29 Sep 2017 23:12:57 +0900 Subject: [PATCH] mtd: nand: denali: fix setup_data_interface to meet tCCS delay The WE_2_RE register specifies the number of clock cycles inserted between the rising edge of #WE and the falling edge of #RE. The current setup_data_interface implementation takes care of tWHR, but tCCS is missing. Wait for max(tCSS, tWHR) to meet the spec. With setup_data_interface() properly programmed, the Denali NAND controller can observe the timing, so NAND_WAIT_TCCS flag is unneeded. Clarify this in the comment block. Signed-off-by: Masahiro Yamada Signed-off-by: Boris Brezillon --- drivers/mtd/nand/denali.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c index 0b268ec88435..5124f8ae8c04 100644 --- a/drivers/mtd/nand/denali.c +++ b/drivers/mtd/nand/denali.c @@ -1004,8 +1004,14 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, tmp |= FIELD_PREP(RE_2_RE__VALUE, re_2_re); iowrite32(tmp, denali->reg + RE_2_RE); - /* tWHR -> WE_2_RE */ - we_2_re = DIV_ROUND_UP(timings->tWHR_min, t_clk); + /* + * tCCS, tWHR -> WE_2_RE + * + * With WE_2_RE properly set, the Denali controller automatically takes + * care of the delay; the driver need not set NAND_WAIT_TCCS. + */ + we_2_re = DIV_ROUND_UP(max(timings->tCCS_min, timings->tWHR_min), + t_clk); we_2_re = min_t(int, we_2_re, TWHR2_AND_WE_2_RE__WE_2_RE); tmp = ioread32(denali->reg + TWHR2_AND_WE_2_RE);