Patch "powerpc/prom_init: Fixup missing powermac #size-cells" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    powerpc/prom_init: Fixup missing powermac #size-cells

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-prom_init-fixup-missing-powermac-size-cells.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 67a2f5aaa31d838813e4d969a762f70d8c53547d
Author: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Date:   Tue Nov 26 13:57:10 2024 +1100

    powerpc/prom_init: Fixup missing powermac #size-cells
    
    [ Upstream commit cf89c9434af122f28a3552e6f9cc5158c33ce50a ]
    
    On some powermacs `escc` nodes are missing `#size-cells` properties,
    which is deprecated and now triggers a warning at boot since commit
    045b14ca5c36 ("of: WARN on deprecated #address-cells/#size-cells
    handling").
    
    For example:
    
      Missing '#size-cells' in /pci@f2000000/mac-io@c/escc@13000
      WARNING: CPU: 0 PID: 0 at drivers/of/base.c:133 of_bus_n_size_cells+0x98/0x108
      Hardware name: PowerMac3,1 7400 0xc0209 PowerMac
      ...
      Call Trace:
        of_bus_n_size_cells+0x98/0x108 (unreliable)
        of_bus_default_count_cells+0x40/0x60
        __of_get_address+0xc8/0x21c
        __of_address_to_resource+0x5c/0x228
        pmz_init_port+0x5c/0x2ec
        pmz_probe.isra.0+0x144/0x1e4
        pmz_console_init+0x10/0x48
        console_init+0xcc/0x138
        start_kernel+0x5c4/0x694
    
    As powermacs boot via prom_init it's possible to add the missing
    properties to the device tree during boot, avoiding the warning. Note
    that `escc-legacy` nodes are also missing `#size-cells` properties, but
    they are skipped by the macio driver, so leave them alone.
    
    Depends-on: 045b14ca5c36 ("of: WARN on deprecated #address-cells/#size-cells handling")
    Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
    Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
    Signed-off-by: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx>
    Link: https://patch.msgid.link/20241126025710.591683-1-mpe@xxxxxxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 6f7ad80763159..9a753c4dafab6 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -2894,7 +2894,7 @@ static void __init fixup_device_tree_chrp(void)
 #endif
 
 #if defined(CONFIG_PPC64) && defined(CONFIG_PPC_PMAC)
-static void __init fixup_device_tree_pmac(void)
+static void __init fixup_device_tree_pmac64(void)
 {
 	phandle u3, i2c, mpic;
 	u32 u3_rev;
@@ -2934,7 +2934,31 @@ static void __init fixup_device_tree_pmac(void)
 		     &parent, sizeof(parent));
 }
 #else
-#define fixup_device_tree_pmac()
+#define fixup_device_tree_pmac64()
+#endif
+
+#ifdef CONFIG_PPC_PMAC
+static void __init fixup_device_tree_pmac(void)
+{
+	__be32 val = 1;
+	char type[8];
+	phandle node;
+
+	// Some pmacs are missing #size-cells on escc nodes
+	for (node = 0; prom_next_node(&node); ) {
+		type[0] = '\0';
+		prom_getprop(node, "device_type", type, sizeof(type));
+		if (prom_strcmp(type, "escc"))
+			continue;
+
+		if (prom_getproplen(node, "#size-cells") != PROM_ERROR)
+			continue;
+
+		prom_setprop(node, NULL, "#size-cells", &val, sizeof(val));
+	}
+}
+#else
+static inline void fixup_device_tree_pmac(void) { }
 #endif
 
 #ifdef CONFIG_PPC_EFIKA
@@ -3159,6 +3183,7 @@ static void __init fixup_device_tree(void)
 	fixup_device_tree_maple_memory_controller();
 	fixup_device_tree_chrp();
 	fixup_device_tree_pmac();
+	fixup_device_tree_pmac64();
 	fixup_device_tree_efika();
 	fixup_device_tree_pasemi();
 }