The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x fd779eac2d659668be4d3dbdac0710afd5d6db12 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025091345-disinfect-afterlife-38dd@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From fd779eac2d659668be4d3dbdac0710afd5d6db12 Mon Sep 17 00:00:00 2001 From: Alexander Sverdlin alexander.sverdlin@gmail.com Date: Thu, 21 Aug 2025 14:00:57 +0200 Subject: [PATCH] mtd: nand: raw: atmel: Respect tAR, tCLR in read setup timing

Having setup time 0 violates tAR, tCLR of some chips, for instance TOSHIBA TC58NVG2S3ETAI0 cannot be detected successfully (first ID byte being read duplicated, i.e. 98 98 dc 90 15 76 14 03 instead of 98 dc 90 15 76 ...).

Atmel Application Notes postulated 1 cycle NRD_SETUP without explanation [1], but it looks more appropriate to just calculate setup time properly.

[1] Link: https://ww1.microchip.com/downloads/aemDocuments/documents/MPU32/Application...

Cc: stable@vger.kernel.org Fixes: f9ce2eddf176 ("mtd: nand: atmel: Add ->setup_data_interface() hooks") Signed-off-by: Alexander Sverdlin alexander.sverdlin@siemens.com Tested-by: Alexander Dahl ada@thorsis.com Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com

diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c index 84ab4a83cbd6..db94d14a3807 100644 --- a/drivers/mtd/nand/raw/atmel/nand-controller.c +++ b/drivers/mtd/nand/raw/atmel/nand-controller.c @@ -1377,14 +1377,24 @@ static int atmel_smc_nand_prepare_smcconf(struct atmel_nand *nand, if (ret) return ret;

+ /* + * Read setup timing depends on the operation done on the NAND: + * + * NRD_SETUP = max(tAR, tCLR) + */ + timeps = max(conf->timings.sdr.tAR_min, conf->timings.sdr.tCLR_min); + ncycles = DIV_ROUND_UP(timeps, mckperiodps); + totalcycles += ncycles; + ret = atmel_smc_cs_conf_set_setup(smcconf, ATMEL_SMC_NRD_SHIFT, ncycles); + if (ret) + return ret; + /* * The read cycle timing is directly matching tRC, but is also * dependent on the setup and hold timings we calculated earlier, * which gives: * - * NRD_CYCLE = max(tRC, NRD_PULSE + NRD_HOLD) - * - * NRD_SETUP is always 0. + * NRD_CYCLE = max(tRC, NRD_SETUP + NRD_PULSE + NRD_HOLD) */ ncycles = DIV_ROUND_UP(conf->timings.sdr.tRC_min, mckperiodps); ncycles = max(totalcycles, ncycles);