Hi Greg,
francesco@dolcini.it wrote on Wed, 25 Jan 2023 22:06:57 +0100:
Hello Miquel, Greg and all
On Tue, Jan 24, 2023 at 04:38:59PM +0100, Greg Kroah-Hartman wrote:
On Tue, Jan 24, 2023 at 11:44:44AM +0100, Francesco Dolcini wrote:
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
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.
v4: fixed wrong English spelling in the comment
v3: minor formatting change, removed not needed new-line and space.
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 | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/drivers/mtd/parsers/ofpart_core.c b/drivers/mtd/parsers/ofpart_core.c index 192190c42fc8..e7b8e9d0a910 100644 --- a/drivers/mtd/parsers/ofpart_core.c +++ b/drivers/mtd/parsers/ofpart_core.c @@ -122,6 +122,25 @@ 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 ugly workaround to not create* regression on devices that are still creating* partitions as direct children 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);This is a driver, always use dev_*() calls, not pr_*() calls so that we know what is being referred to exactly.
Is this reasonable here? Where can I get the struct device?
In general this file uses only pr_* debug API and messages are about OF nodes/properties, not about a device.
I'm also skeptical here, this is not a device driver, it's a generic parser and it seems more appropriate to warn about an of node rather than a struct device.
MTD devices inherit from struct device (mtd->dev) which I guess might be used here. The bus infrastructure device (mtd->device->parents) is less appropriate as it sometimes points at the controller (raw NAND) and sometimes at the spi device (SPI-NAND, SPI NOR).
pr_warn is fine here IMHO, but if Greg insist, switch it to dev_warn, I don't mind. Maybe it is worth testing that dev_warn still displays an easy-to-understand message in that case.
I take back my "reviewed-by" line above, please fix this up to not need pr_warn, but to use dev_warn() instead.
Francesco
Thanks, Miquèl