mtd: rawnand: arasan: Fix clock rate in NV-DDR

[ Upstream commit e16eceea863b417fd328588b1be1a79de0bc937f ]

According to the Arasan NAND controller spec, the flash clock rate for SDR
must be <= 100 MHz, while for NV-DDR it must be the same as the rate of the
CLK line for the mode. The driver previously always set 100 MHz for NV-DDR,
which would result in incorrect behavior for NV-DDR modes 0-4.

The appropriate clock rate can be calculated from the NV-DDR timing
parameters as 1/tCK, or for rates measured in picoseconds,
10^12 / nand_nvddr_timings->tCK_min.

Fixes: 197b88fecc50 ("mtd: rawnand: arasan: Add new Arasan NAND controller")
CC: stable@vger.kernel.org # 5.8+
Signed-off-by: Olga Kitaina <okitain@gmail.com>
Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220628154824.12222-3-amit.kumar-mahapatra@xilinx.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/mtd/nand/raw/arasan-nand-controller.c b/drivers/mtd/nand/raw/arasan-nand-controller.c
index f926d658192ba190884ba8f9eb541c0b4f149924..50643c6f33f4855c0c1418626eb20db5881a0a99 100644 (file)
--- a/drivers/mtd/nand/raw/arasan-nand-controller.c
+++ b/drivers/mtd/nand/raw/arasan-nand-controller.c
@@ -907,7 +907,13 @@ static int anfc_setup_interface(struct nand_chip *chip, int target,
                anand->timings = DIFACE_NVDDR |
                                 DIFACE_DDR_MODE(conf->timings.mode);
 
-       anand->clk = ANFC_XLNX_SDR_DFLT_CORE_CLK;
+       if (nand_interface_is_sdr(conf)) {
+               anand->clk = ANFC_XLNX_SDR_DFLT_CORE_CLK;
+       } else {
+               /* ONFI timings are defined in picoseconds */
+               anand->clk = div_u64((u64)NSEC_PER_SEC * 1000,
+                                    conf->timings.nvddr.tCK_min);
+       }
 
        /*
         * Due to a hardware bug in the ZynqMP SoC, SDR timing modes 0-1 work