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openwrt/target/linux/ramips/dts/mt7621_xiaomi_mi-router-4a-3g-v2.dtsi
David Bentham 17e690017d ramips: reduce spi-max-frequency for Xiaomi MI Router 4AG
Reduce spi-max-frequency for Xiaomi MI Router 4AG model

Xiaomi MI Router 4AG MTD uses two flash chips (no specific on router versions when produced from factory) - GD25Q128C and W25Q128BV.

These flash chips are capable of high frequency, but due to poor board design or manufacture process.

We are seeing the following errors in the linux kernel bootup:

`spi-nor spi0.0: unrecognized JEDEC id bytes: cc 60 1c cc 60 1c
 spi-nor: probe of spi0.0 failed with error -2`

This causes the partitions not to be detected

`VFS: Cannot open root device "(null)" or unknown-block(0,0): error -6`

Then creates a bootloop and a bricked router.

The solution to limit this race condition is to reduce the frequency from 80 mhz to 50 mhz.

Signed-off-by: David Bentham <db260179@gmail.com>
2021-04-17 21:56:05 +02:00

163 lines
2.5 KiB
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// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
#include "mt7621.dtsi"
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/input/input.h>
/ {
aliases {
led-boot = &led_status_yellow;
led-failsafe = &led_status_yellow;
led-running = &led_status_blue;
led-upgrade = &led_status_yellow;
label-mac-device = &wan;
};
chosen {
bootargs = "console=ttyS0,115200n8";
};
leds {
compatible = "gpio-leds";
led_status_blue: status_blue {
label = "blue:status";
gpios = <&gpio 8 GPIO_ACTIVE_LOW>;
};
led_status_yellow: status_yellow {
label = "yellow:status";
gpios = <&gpio 10 GPIO_ACTIVE_LOW>;
};
};
keys {
compatible = "gpio-keys";
reset {
label = "reset";
gpios = <&gpio 18 GPIO_ACTIVE_LOW>;
linux,code = <KEY_RESTART>;
};
};
};
&spi0 {
status = "okay";
flash@0 {
compatible = "jedec,spi-nor";
reg = <0>;
spi-max-frequency = <50000000>;
m25p,fast-read;
partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;
partition@0 {
label = "u-boot";
reg = <0x0 0x30000>;
read-only;
};
partition@30000 {
label = "u-boot-env";
reg = <0x30000 0x10000>;
read-only;
};
partition@40000 {
label = "Bdata";
reg = <0x40000 0x10000>;
read-only;
};
factory: partition@50000 {
label = "factory";
reg = <0x50000 0x10000>;
read-only;
};
partition@60000 {
label = "crash";
reg = <0x60000 0x10000>;
read-only;
};
partition@70000 {
label = "cfg_bak";
reg = <0x70000 0x10000>;
read-only;
};
partition@80000 {
label = "overlay";
reg = <0x80000 0x100000>;
read-only;
};
firmware: partition@180000 {
compatible = "denx,uimage";
label = "firmware";
reg = <0x180000 0xe80000>;
};
};
};
};
&pcie {
status = "okay";
};
&pcie0 {
wifi@0,0 {
compatible = "pci14c3,7662";
reg = <0x0000 0 0 0 0>;
mediatek,mtd-eeprom = <&factory 0x8000>;
ieee80211-freq-limit = <5000000 6000000>;
};
};
&pcie1 {
wifi@0,0 {
compatible = "pci14c3,7603";
reg = <0x0000 0 0 0 0>;
mediatek,mtd-eeprom = <&factory 0x0000>;
ieee80211-freq-limit = <2400000 2500000>;
};
};
&gmac0 {
mtd-mac-address = <&factory 0xe000>;
};
&switch0 {
ports {
port@2 {
status = "okay";
label = "lan2";
};
port@3 {
status = "okay";
label = "lan1";
};
wan: port@4 {
status = "okay";
label = "wan";
mtd-mac-address = <&factory 0xe006>;
};
};
};
&state_default {
gpio {
groups = "jtag", "uart2", "uart3", "wdt";
function = "gpio";
};
};