Peter Maydell <peter.mayd...@linaro.org> writes:
> On Tue, 16 May 2023 at 11:44, Alex Bennée <alex.ben...@linaro.org> wrote: >> >> The commit b3aa2f2128 (target/arm: provide stubs for more external >> debug registers) was added to handle HyperV's unconditional usage of >> Debug Communications Channel. It turns out that Linux will similarly >> break if you enable CONFIG_HVC_DCC "ARM JTAG DCC console". >> >> Extend the registers we RAZ/WI set to avoid this. > > Applied to target-arm.next, thanks. > > (In theory we could implement the DCC and wire it up to a > chardev, which might be a cute way of getting early debug.) I wondered about that - does DCC give you anything that you can't get with semihosting (which I think also can support earlycon)? I found it a little unclear if this is an always available feature. Should you expect any modern Cortex/Arm chip to support DCC when attached to jtag? -- Alex Bennée Virtualisation Tech Lead @ Linaro
