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Diffstat (limited to 'gitlab/issues/target_riscv/host_missing/accel_missing/2796.toml')
| -rw-r--r-- | gitlab/issues/target_riscv/host_missing/accel_missing/2796.toml | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/gitlab/issues/target_riscv/host_missing/accel_missing/2796.toml b/gitlab/issues/target_riscv/host_missing/accel_missing/2796.toml new file mode 100644 index 000000000..9d80b41ac --- /dev/null +++ b/gitlab/issues/target_riscv/host_missing/accel_missing/2796.toml @@ -0,0 +1,17 @@ +id = 2796 +title = "Opentitan Timer ignores COMPARE_UPPER0/COMPARE_LOWER0" +state = "opened" +created_at = "2025-01-27T22:06:46.621Z" +closed_at = "n/a" +labels = ["target: riscv"] +url = "https://gitlab.com/qemu-project/qemu/-/issues/2796" +host-os = "Ubuntu 22.04.3" +host-arch = "x86" +qemu-version = "9.1.1" +guest-os = "Bare Metal" +guest-arch = "riscv32" +description = """In a bare metal application, running on an emulated Opentitan board, if you set a timer interrupt threshold by writing to `rv_timer.COMPARE_UPPER0` and `rv_timer.COMPARE_LOWER0` before writing to `rv_timer.CTRL` to start the timer, then the interrupt does not fire. If you write to the `COMPARE_*` registers *after* starting the timer by writing to `CTRL`, then the interrupt fires correctly. + +I think the explanation is that [ibex_timer_update_irqs](https://gitlab.com/qemu-project/qemu/-/blob/master/hw/timer/ibex_timer.c?ref_type=heads#L61) has an early return if `rv_timer.CTRL` is not set. As a result, although writes to `COMPARE_*` always call `ibex_timer_update_irqs`, they don't have their intended side-effects before `CTRL` is unset.""" +reproduce = """Write to `rv_timer.COMPARE_UPPER0` and `rv_timer.COMPARE_LOWER0` before you have set `rv_timer.CTRL`. Observe that no timer interrupt occurs.""" +additional = "n/a" |