From: Martino Dell'Ambrogio <tillo@tillo•ch>
To: matthias.bgg@gmail•com, angelogioacchino.delregno@collabora•com
Cc: kees@kernel•org, tony.luck@intel•com, gpiccoli@igalia•com,
linux-mediatek@lists•infradead.org,
linux-arm-kernel@lists•infradead.org, devicetree@vger•kernel.org,
linux-kernel@vger•kernel.org,
Martino Dell'Ambrogio <tillo@tillo•ch>
Subject: [PATCH] arm64: dts: mediatek: mt7986a-bananapi-bpi-r3: add ramoops region
Date: Thu, 28 May 2026 11:30:38 +0200 [thread overview]
Message-ID: <20260528093038.1945245-1-tillo@tillo.ch> (raw)
Reserve 64 KiB of RAM just below the ARM Trusted Firmware secmon region
(0x42ff0000-0x43000000) for persistent kernel log storage via pstore/ramoops,
allowing post-panic console output and oops dumps to be recovered after a
warm reset. Without it, kernel crash logs on this board are lost when the
SoC reboots.
The carve-out is divided into 8 KiB kmsg records, a 32 KiB rolling console,
8 KiB ftrace, and 8 KiB pmsg, leaving the remainder for the per-record
Reed-Solomon ECC parity (ecc-size=16) which significantly improves dump
readability when the panic path truncates writes mid-record.
The region sits immediately below the ATF block already declared at
0x43000000 in mt7986a.dtsi, so no other reserved-memory child is moved or
resized. BPI-R3 ships with 2 GiB of DRAM starting at 0x40000000, well above
0x43000000, so the region is always within installed memory.
For the carve-out to actually preserve content across a reset, the boot
loader must avoid touching this region on warm reset; on standard BPI-R3
boards with the stock OpenWrt U-Boot fork this already holds.
Signed-off-by: Martino Dell'Ambrogio <tillo@tillo•ch>
---
.../boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
index 19f538d..31ee189 100644
--- a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
+++ b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
@@ -140,6 +140,18 @@ sfp2: sfp-2 {
};
};
+&{/reserved-memory} {
+ ramoops@42ff0000 {
+ compatible = "ramoops";
+ reg = <0 0x42ff0000 0 0x10000>;
+ record-size = <0x2000>;
+ console-size = <0x8000>;
+ ftrace-size = <0x2000>;
+ pmsg-size = <0x2000>;
+ ecc-size = <16>;
+ };
+};
+
&cpu_thermal {
cooling-maps {
map-cpu-active-high {
--
2.47.3
next reply other threads:[~2026-05-28 9:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-28 9:30 Martino Dell'Ambrogio [this message]
2026-05-28 12:36 ` [PATCH v2] arm64: dts: mediatek: mt7988a-bananapi-bpi-r4: add ramoops region Martino Dell'Ambrogio
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