diff options
authorPeter Maydell <peter.maydell@linaro.org>2020-08-25 17:08:47 +0100
committerPeter Maydell <peter.maydell@linaro.org>2020-09-14 14:23:19 +0100
commitc9ebc8c207e997c01d459529fd83ffd85c66cf9d (patch)
parentae689ad7a89eff2e6222bbe30710a30cc7625538 (diff)
hw/timer/armv7m_systick: assert that board code set system_clock_scale
It is the responsibility of board code for an armv7m system to set system_clock_scale appropriately for the CPU speed of the core. If it forgets to do this, then QEMU will hang if the guest tries to use the systick timer in the "tick at the CPU clock frequency" mode. We forgot that in a couple of our boards (see commits ce4f70e81ed23c93f, e7e5a9595ab1136). Add an assertion in the systick reset method so we don't let any new boards in with the same bug. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20200825160847.18091-1-peter.maydell@linaro.org
1 files changed, 8 insertions, 0 deletions
diff --git a/hw/timer/armv7m_systick.c b/hw/timer/armv7m_systick.c
index 74c58bcf24..a8cec7eb56 100644
--- a/hw/timer/armv7m_systick.c
+++ b/hw/timer/armv7m_systick.c
@@ -202,6 +202,14 @@ static void systick_reset(DeviceState *dev)
SysTickState *s = SYSTICK(dev);
+ /*
+ * Forgetting to set system_clock_scale is always a board code
+ * bug. We can't check this earlier because for some boards
+ * (like stellaris) it is not yet configured at the point where
+ * the systick device is realized.
+ */
+ assert(system_clock_scale != 0);
s->control = 0;
s->reload = 0;
s->tick = 0;