Hi Francesco,

francesco@dolcini.it wrote on Fri, 13 Jan 2023 19:45:56 +0100:

From: Francesco Dolcini francesco.dolcini@toradex.com

Add a mechanism to handle the case in which partitions are present as direct child of the nand controller node and #size-cells is set to <0>.

This could happen if the nand-controller node in the DTS is supposed to have #size-cells set to 0, but for some historical reason/bug it was set to 1 in the past, and the firmware (e.g. U-Boot) is adding the partition as direct children of the nand-controller defaulting to #size-cells being to 1.

This prevents a real boot failure on colibri-imx7 that happened during v6.1 development cycles.

Link: https://lore.kernel.org/all/Y4dgBTGNWpM6SQXI@francesco-nb.int.toradex.com/ Link: https://lore.kernel.org/all/20221202071900.1143950-1-francesco@dolcini.it/ Signed-off-by: Francesco Dolcini francesco.dolcini@toradex.com Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

---

Miquel, Marek: I do not expect this patch to be backported to stable, however I would expect that we do not backport nand-controller dts cleanups neither.

Okay.

v2: fixup size-cells only when partitions are direct children of the nand-controller completely revised commit message, comments and warning print use pr_warn instead of pr_warn_once added Reviewed-by Greg removed cc:stable@ and fixes tag, since the problematic commit was reverted

---

drivers/mtd/parsers/ofpart_core.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)

diff --git a/drivers/mtd/parsers/ofpart_core.c b/drivers/mtd/parsers/ofpart_core.c index 192190c42fc8..46559a9248e6 100644 --- a/drivers/mtd/parsers/ofpart_core.c +++ b/drivers/mtd/parsers/ofpart_core.c @@ -122,6 +122,26 @@ static int parse_fixed_partitions(struct mtd_info *master,

a_cells = of_n_addr_cells(pp);
s_cells = of_n_size_cells(pp);

• if (!dedicated && s_cells == 0) {
  

• 	/*
  

• 	 * This is a hugly workaround to not create
  

• 	 * regression on devices that are still creating
  

• 	 * partitions as direct child of the nand controller.
  

• 	 * This can happen in case the nand controller node has
  

• 	 * #size-cells equal to 0 and the firmware (e.g.
  

• 	 * U-Boot) just add the partitions there assuming
  

• 	 * 32-bit addressing.
  

• 	 *
  

• 	 * If you get this warning your firmware and/or DTS
  

• 	 * should be really fixed.
  

• 	 *
  

• 	 * This is working only for devices smaller than 4GiB.
  

• 	 */
  

• 	pr_warn("%s: ofpart partition %pOF (%pOF) #size-cells is wrongly set to <0>, assuming <1> for parsing partitions.\n",
  

• 		 master->name, pp,
  

• 		 mtd_node);
  

Why mtd_node on a new line?

Otherwise looks good to me.

• 	s_cells = 1;
  

• }
  

  if (len / 4 != a_cells + s_cells) { pr_debug("%s: ofpart partition %pOF (%pOF) error parsing reg property.\n", master->name, pp,

Thanks, Miquèl