From: Stephan Gerhold stephan@gerhold.net
[ Upstream commit 8f4a7a00c1019df72cda3002643fb5823ef39183 ]
At the moment, writing large amounts of data to the eMMC causes the device to freeze. The symptoms vary, sometimes the device reboots immediately, but usually it will just get stuck.
It turns out that the issue is not actually related to the eMMC: Apparently, Samsung has made some modifications to the TrustZone firmware. These require additional memory which is reserved at 0x85500000-0x86000000. The downstream kernel describes this memory reservation as:
/* Additionally Reserved 6MB for TIMA and Increased the TZ app size * by 2MB [total 8 MB ] */
This suggests that it is used for additional TZ apps, although the extra memory is actually 11 MB instead of the 8 MB mentioned in the comment.
Writing to the protected memory causes the kernel to crash or freeze. In our case, writing to the eMMC causes the disk cache to fill the available RAM, until the kernel eventually crashes when attempting to use the reserved memory.
Add the additional memory as reserved-memory to fix this problem.
Fixes: 1329c1ab0730 ("arm64: dts: qcom: Add device tree for Samsung Galaxy A3U/A5U") Reported-by: Michael Srba Michael.Srba@seznam.cz Tested-by: Michael Srba Michael.Srba@seznam.cz # a3u Tested-by: Stephan Gerhold stephan@gerhold.net # a5u Signed-off-by: Stephan Gerhold stephan@gerhold.net Link: https://lore.kernel.org/r/20191231112511.83342-1-stephan@gerhold.net Signed-off-by: Bjorn Andersson bjorn.andersson@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- .../arm64/boot/dts/qcom/msm8916-samsung-a2015-common.dtsi | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/arch/arm64/boot/dts/qcom/msm8916-samsung-a2015-common.dtsi b/arch/arm64/boot/dts/qcom/msm8916-samsung-a2015-common.dtsi index bd1eb3eeca53f..43c5e0f882f14 100644 --- a/arch/arm64/boot/dts/qcom/msm8916-samsung-a2015-common.dtsi +++ b/arch/arm64/boot/dts/qcom/msm8916-samsung-a2015-common.dtsi @@ -15,6 +15,14 @@ stdout-path = "serial0"; };
+ reserved-memory { + /* Additional memory used by Samsung firmware modifications */ + tz-apps@85500000 { + reg = <0x0 0x85500000 0x0 0xb00000>; + no-map; + }; + }; + soc { sdhci@7824000 { status = "okay";