Historically, The mtime/mtimecmp has been part of the CPU because
they are per hart entities. However, they actually belong to aclint
which is a MMIO device.
Move them to the ACLINT device. This also emulates the real hardware
more closely.
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220824221357.41070-2-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
RISC-V privilege spec defines that mtime is exposed as a memory-mapped
machine-mode read-write register. However, as QEMU uses host monotonic
timer as timer source, this makes mtime to be read-only in RISC-V
ACLINT.
This patch makes mtime to be writable by recording the time delta value
between the mtime value to be written and the timer value at the time
mtime is written. Time delta value is then added back whenever the timer
value is retrieved.
Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Jim Shu <jim.shu@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220420080901.14655-4-frank.chang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The RISC-V ACLINT is more modular and backward compatible with
original SiFive CLINT so instead of duplicating the original
SiFive CLINT implementation we upgrade the current SiFive CLINT
implementation to RISC-V ACLINT implementation.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-id: 20210831110603.338681-3-anup.patel@wdc.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
We will be upgrading SiFive CLINT implementation into RISC-V ACLINT
implementation so let's first rename the sources.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-id: 20210831110603.338681-2-anup.patel@wdc.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
