arm64: dts: bcm4908: nvmem-layout conversion

nvmem-layout is a more flexible replacement for nvmem-cells.

Signed-off-by: Rosen Penev <[email protected]>
Link: https://lore.kernel.org/r/2024120323363

arm64: dts: bcm4908: nvmem-layout conversion

nvmem-layout is a more flexible replacement for nvmem-cells.

Signed-off-by: Rosen Penev <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Florian Fainelli <[email protected]>

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arm64: dts: broadcom: bcmbca: bcm4908: Add DT for Zyxel EX3510-B

Zyxel EX3510-B is a WiFi 6 capable home gateway (family) based on the
BCM4906 SoC, with 512MiB of RAM and 512MiB of NAND flash. WiFi

arm64: dts: broadcom: bcmbca: bcm4908: Add DT for Zyxel EX3510-B

Zyxel EX3510-B is a WiFi 6 capable home gateway (family) based on the
BCM4906 SoC, with 512MiB of RAM and 512MiB of NAND flash. WiFi support
consists of a BCM6710 and a BCM6715 attached to separate PCIe buses.

Add an initial devicetree for this system, with support for:
- Onboard UART (per base dtsi)
- USB (2.0 only; superspeed devices are treated as high-speed due to an
unknown cause)
- Both buttons (rear reset, front WPS)
- Almost all LEDs:
- Power (red/green)
- Internet (red/green)
- WAN (green)
- LAN (green; anode is connected to GPIO 13 so currently
nonfunctioning)
- USB (green)
- WPS button (red/green)
- Absent in DT: There are 2.4GHz/5.0GHz WiFi status LEDs connected to
the WiFi chips instead of the SoC.
- NAND flash
- Embedded Ethernet switch
- Factory-programmed Ethernet MAC address

WiFi cannot be enabled at this time due to Linux lacking drivers for
both the PCIe controllers and the PCIe WiFi peripherals.

Signed-off-by: Sam Edwards <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Florian Fainelli <[email protected]>

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arm64: dts: broadcom: bcmbca: bcm4908: Protect cpu-release-addr

The `cpu-release-addr` property is relevant only when the "spin-table"
enable method is used. It is the physical address where the boo

arm64: dts: broadcom: bcmbca: bcm4908: Protect cpu-release-addr

The `cpu-release-addr` property is relevant only when the "spin-table"
enable method is used. It is the physical address where the bootloader
expects Linux to write the secondary CPU entry point's physical address.
On this platform, only the CFE bootloader uses this method: U-Boot uses
PSCI instead.

CFE actually walks the FDT to learn this address, so we're free to put
it wherever we want. We only need to make sure that it goes in a
reserved-memory block so that writing to it during early boot does not
risk conflicting with an unrelated memory allocation: this was not done.

Since the previous patch reserved the first page of memory for CFE's
secondary-CPU init stub, which is actually much smaller than a page,
just put this address at the end of that page and it shall be so
protected.

Signed-off-by: Sam Edwards <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Florian Fainelli <[email protected]>

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arm64: dts: broadcom: bcmbca: bcm4908: Reserve CFE stub area

The CFE bootloader places a stub program in the first page of physical
memory to hold the secondary CPUs until the boot CPU writes the re

arm64: dts: broadcom: bcmbca: bcm4908: Reserve CFE stub area

The CFE bootloader places a stub program in the first page of physical
memory to hold the secondary CPUs until the boot CPU writes the release
address, but does not splice a /reserved-memory node into the FDT to
protect it. If Linux overwrites this program before execution reaches
smp_prepare_cpus(), the secondary CPUs may become inaccessible.

This is only a problem with CFE, and then only until the secondary CPUs
are brought online. Ideally, there would be some hypothetical mechanism
we could use to indicate that this area of memory is sensitive only
during boot. But as there is none, and since it is such a small amount
of memory, it is easiest to reserve it unconditionally.

Therefore, add a /reserved-memory node to bcm4908.dtsi to protect the
first 4KiB of physical memory.

Signed-off-by: Sam Edwards <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Florian Fainelli <[email protected]>

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