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authorLinus Walleij <linus.walleij@linaro.org>2015-10-28 10:39:55 +0100
committerOlof Johansson <olof@lixom.net>2015-10-31 01:31:01 +0000
commit980bbff018f64a22af0e75a12ee14cbfbc547e6a (patch)
tree7da176991118d3efa63271348d9f73221963fc27 /arch/arm64
parent7c62f299bafef82c83169ac0c4cf77874446fc83 (diff)
ARM64: juno: disable NOR flash node by default
After discussing on the mailing list it turns out that accessing the flash memory from the kernel can disrupt CPU sleep states and CPU hotplugging, so let's disable this DT node by default. Setups that want to access the flash can modify this entry to enable the flash again. Quoting Sudeep Holla: "the firmware assumes the flash is always in read mode while Linux leaves NOR flash in "read id" mode after initialization." Reported-by: Sudeep Holla <sudeep.holla@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Liviu Dudau <Liviu.Dudau@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Leif Lindholm <leif.lindholm@arm.com> Cc: Ryan Harkin <ryan.harkin@linaro.org> Fixes: 5078f77e1443 "ARM64: juno: add NOR flash to device tree" Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Olof Johansson <olof@lixom.net>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/boot/dts/arm/juno-motherboard.dtsi7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm64/boot/dts/arm/juno-motherboard.dtsi b/arch/arm64/boot/dts/arm/juno-motherboard.dtsi
index c7c99a42e2e9..8c029ee2a5b5 100644
--- a/arch/arm64/boot/dts/arm/juno-motherboard.dtsi
+++ b/arch/arm64/boot/dts/arm/juno-motherboard.dtsi
@@ -109,6 +109,13 @@
linux,part-probe = "afs";
reg = <0 0x00000000 0x04000000>;
bank-width = <4>;
+ /*
+ * Unfortunately, accessing the flash disturbs
+ * the CPU idle states (suspend) and CPU
+ * hotplug of the platform. For this reason,
+ * flash hardware access is disabled by default.
+ */
+ status = "disabled";
};
ethernet@2,00000000 {