RISC-V: Resurrect the MMIO timer implementation for M-mode systems
The K210 doesn't implement rdtime in M-mode, and since that's where Linux runs
in the NOMMU systems that means we can't use rdtime. The K210 is the only
system that anyone is currently running NOMMU or M-mode on, so here we're just
inlining the timer read directly.
This also adds the CLINT driver as an !MMU dependency, as it's currently the
only timer driver availiable for these systems and without it we get a build
failure for some configurations.
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index df18372..7766e12 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -32,6 +32,7 @@
select ARCH_WANT_FRAME_POINTERS
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
select CLONE_BACKWARDS
+ select CLINT_TIMER if !MMU
select COMMON_CLK
select EDAC_SUPPORT
select GENERIC_ARCH_TOPOLOGY if SMP
