linux-kernel - [PATCH] of: Add Google Juniper to excluded default cells list

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Message-ID: <20241125113151.107812-1-krzysztof.kozlowski@linaro.org>
Date: Mon, 25 Nov 2024 12:31:51 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Rob Herring <robh@...nel.org>,
	Saravana Kannan <saravanak@...gle.com>,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Sasha Levin <sashal@...nel.org>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	Chen-Yu Tsai <wenst@...omium.org>,
	Conor Dooley <conor@...nel.org>
Subject: [PATCH] of: Add Google Juniper to excluded default cells list

Google Juniper platforms have a very old bootloader which populates
/firmware node without proper address/size-cells leading to warnings:

  Missing '#address-cells' in /firmware
  WARNING: CPU: 0 PID: 1 at drivers/of/base.c:106 of_bus_n_addr_cells+0x90/0xf0
  Modules linked in:
  CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0 #1 933ab9971ff4d5dc58cb378a96f64c7f72e3454d
  Hardware name: Google juniper sku16 board (DT)
  ...
  Missing '#size-cells' in /firmware
  WARNING: CPU: 0 PID: 1 at drivers/of/base.c:133 of_bus_n_size_cells+0x90/0xf0
  Modules linked in:
  CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G        W          6.12.0 #1 933ab9971ff4d5dc58cb378a96f64c7f72e3454d
  Tainted: [W]=WARN
  Hardware name: Google juniper sku16 board (DT)

The platform won't receive updated bootloader/firmware so add it to
excluded platform list to silence the warning.

Reported-by: Sasha Levin <sashal@...nel.org>
Closes: https://lore.kernel.org/all/Z0NUdoG17EwuCigT@sashalap/
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Cc: Matthias Brugger <matthias.bgg@...il.com>
Cc: Chen-Yu Tsai <wenst@...omium.org>
Cc: Conor Dooley <conor@...nel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
---
 drivers/of/base.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index a8b0c42bdc8e..13f0b2877ee0 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -56,6 +56,16 @@ DEFINE_MUTEX(of_mutex);
  */
 DEFINE_RAW_SPINLOCK(devtree_lock);
 
+/*
+ * List of machines running old firmware without explicit #address-cells and
+ * #size-cells values for parent nodes, which are most likely not going get any
+ * update.
+ */
+static const char * const excluded_default_cells_compats[] = {
+	"google,juniper",
+	NULL
+};
+
 bool of_node_name_eq(const struct device_node *np, const char *name)
 {
 	const char *node_name;
@@ -91,6 +101,17 @@ static bool __of_node_is_type(const struct device_node *np, const char *type)
 	IS_ENABLED(CONFIG_SPARC) \
 )
 
+static bool excluded_default_cells_machines(void)
+{
+	/* Do not repeat the machine checks for every bus */
+	static int excluded_machine = -1;
+
+	if (excluded_machine < 0)
+		excluded_machine = of_machine_compatible_match(excluded_default_cells_compats);
+
+	return !!excluded_machine;
+}
+
 int of_bus_n_addr_cells(struct device_node *np)
 {
 	u32 cells;
@@ -103,7 +124,7 @@ int of_bus_n_addr_cells(struct device_node *np)
 		 * is deprecated. Any platforms which hit this warning should
 		 * be added to the excluded list.
 		 */
-		WARN_ONCE(!EXCLUDED_DEFAULT_CELLS_PLATFORMS,
+		WARN_ONCE(!EXCLUDED_DEFAULT_CELLS_PLATFORMS && !excluded_default_cells_machines(),
 			  "Missing '#address-cells' in %pOF\n", np);
 	}
 	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
@@ -125,12 +146,13 @@ int of_bus_n_size_cells(struct device_node *np)
 	for (; np; np = np->parent) {
 		if (!of_property_read_u32(np, "#size-cells", &cells))
 			return cells;
+
 		/*
 		 * Default root value and walking parent nodes for "#size-cells"
 		 * is deprecated. Any platforms which hit this warning should
 		 * be added to the excluded list.
 		 */
-		WARN_ONCE(!EXCLUDED_DEFAULT_CELLS_PLATFORMS,
+		WARN_ONCE(!EXCLUDED_DEFAULT_CELLS_PLATFORMS && !excluded_default_cells_machines(),
 			  "Missing '#size-cells' in %pOF\n", np);
 	}
 	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
-- 
2.43.0