New Linux Patches Trying To Mainline Renesas SH7305 CPU Support

The Renesas SH7305 isn't a new processor and is well known for powering various Casio graphing calculators over the past decde and a half. But finally the mainline Linux kernel may end up seeing support for this 32-bit SH-4a RISC core.

An open-source developer began sending out patches today adding initial SuperH support for the Renesas SH7305 processor. The initial patches fix some compiler flags for building for this processor and introducing the SH7304 CPU type and the Kconfig infrastructure. This is said to be the first small architecture portion of the ongoing SH7305 enablement effort. Additional patches are expected soon with further enabling around the clocks, interrupt controller, timer, and board support.

The Renesas SH7305 SH-4 processor lacks an FPU and clocks only around ~118MHz. This chip is known to be used by various Casio graphing calculators.

Getting Linux running on the SH7305 is interesting though with a limited scope considering the CPU capabilities and also the SH7305 typically being paired with around just ~8MB of RAM.

In any case for those interested in Renesas SuperH hardware on Linux can find these initial SH7305 patches out this morning on the kernel mailing list. We'll see if this effort comes to fruition and maintains the developers' interests long enough for getting to the mainline tree, especially during these times of which a lot of old hardware driver code is being stripped from the kernel due to AI/LLM activity and increased bug reporting.