[PATCH] RISC-V: Allow drivers to provide custom read_cycles64 for M-mode kernel

[Christoph Hellwig]

On Fri, Sep 04, 2020 at 09:51:21PM +0530, Anup Patel wrote:
> The TIME CSR is usually not present on most RISC-V systems so the
> M-mode firmware will emulate the TIME CSR for the S-mode (MMU) kernel
> whereas the M-mode (NoMMU) kernel will have to use MMIO clocksource.
> 
> Currently, the get_cycles() implementation in asm/timex.h does not
> consider the above fact so we provide alternate implementation of
> the get_cycles() for the M-mode (NoMMU) kernel which expects drivers
> to provide custom MMIO based read_cycles64() method.

Please just go back to the previous working version without all the
crazy indirections.

The whole timer and irq code has been turned into a giant maze of
indirections lately.