Hi Geert,

On Fri, Apr 18, 2014 at 10:04:15AM +0200, Geert Uytterhoeven wrote:
> On Thu, Apr 17, 2014 at 7:42 PM, Leif Lindholm <leif.lindh...@linaro.org> 
> wrote:
> > In order to deal with an firmware bug on a specific ppc32 platform
> > (longtrail), early_init_dt_scan_memory() looks for a node called
> > memory@0 on all platforms. Restrict this quirk to ppc32 kernels only.
> 
> This breaks backwards compatibilty with old DTSes (at least on ARM/MIPS,
> where you added the missing property in patches 1 and 2 of the series)?

As Rob said in response to 0/3, the MIPSs would likely not be affected,
since they embed the DT.

> For the Longtrail, I don't care much anymore, as mine died in 2004.
> AFAIK, there have never been many users anyway.

There are still a few mentions of it under arch/powerpc/, so I wouldn't
want to be the one to kill it off...

How about the below v2 3/3 to address the ARM platform?

Regards,

Leif

>From 6fa0b837ad71780334eb97d63c507165b6c57add Mon Sep 17 00:00:00 2001
From: Leif Lindholm <leif.lindh...@linaro.org>
Date: Thu, 17 Apr 2014 14:24:47 +0100
Subject: [PATCH] of: arm: powerpc: Restrict memory@0 node handling to
 affected platforms

In order to deal with a firmware bug on a specific ppc32 platform
(longtrail), early_init_dt_scan_memory() looks for a node called
memory@0 on all platforms, for all nodes lacking a device_type.
Restrict this quirk to ppc32 and the arm mach-ux500 platforms (one of
which has depended on this special handling).

Signed-off-by: Leif Lindholm <leif.lindh...@linaro.org>
Cc: Grant Likely <grant.lik...@linaro.org>
Cc: Lee Jones <lee.jo...@linaro.org>
Cc: Mark Rutland <mark.rutl...@arm.com>
Cc: devicetree@vger.kernel.org
---
 arch/arm/mach-ux500/Kconfig |    1 +
 arch/powerpc/Kconfig        |    1 +
 drivers/of/Kconfig          |    3 +++
 drivers/of/fdt.c            |   10 +++++++++-
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-ux500/Kconfig b/arch/arm/mach-ux500/Kconfig
index b41a42d..e6b0c3b 100644
--- a/arch/arm/mach-ux500/Kconfig
+++ b/arch/arm/mach-ux500/Kconfig
@@ -13,6 +13,7 @@ config ARCH_U8500
        select CLKSRC_NOMADIK_MTU
        select HAVE_ARM_SCU if SMP
        select HAVE_ARM_TWD if SMP
+       select OF_MEMORY_AT_0_QUIRK
        select PINCTRL
        select PINCTRL_ABX500
        select PINCTRL_NOMADIK
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e099899..d78452d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -3,6 +3,7 @@ source "arch/powerpc/platforms/Kconfig.cputype"
 config PPC32
        bool
        default y if !PPC64
+       select OF_MEMORY_AT_0_QUIRK
 
 config 32BIT
        bool
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 889005f..230c747 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -77,4 +77,7 @@ config OF_RESERVED_MEM
        help
          Helpers to allow for reservation of memory regions
 
+config OF_MEMORY_AT_0_QUIRK
+       def_bool n
+
 endmenu # OF
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index fa16a91..1b80b94 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -887,14 +887,22 @@ int __init early_init_dt_scan_memory(unsigned long node, 
const char *uname,
 
        /* We are scanning "memory" nodes only */
        if (type == NULL) {
+#ifdef CONFIG_OF_MEMORY_AT_0_QUIRK
                /*
                 * The longtrail doesn't have a device_type on the
                 * /memory node, so look for the node called /memory@0.
+                * Converted to generic quirk to handle later platforms
+                * with inforrect DTs that work only because of this
+                * special handling.
                 */
                if (depth != 1 || strcmp(uname, "memory@0") != 0)
                        return 0;
-       } else if (strcmp(type, "memory") != 0)
+#else
+               return 0;
+#endif
+       } else if (strcmp(type, "memory") != 0) {
                return 0;
+       }
 
        reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
        if (reg == NULL)
-- 
1.7.10.4

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