| Message ID | CAF++6AOnuOzwiiPRJEGatzX7LuoJKU5ij2xWRLkKbxhytJscqA@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On 13 January 2017 at 12:35, James Hanley <jhanley@dgtlrift.com> wrote: > How should system_clock_scale be set in hw/intc/armv7m_nvic.c - there is no > API for the global, and I've defaulted the global to SYSTICK_SCALE which > seems to work, but is not obvious. This was needed as this value was set to > zero and the arm firmware was selecting the external clock source causing > zero to be returned from systick_scale() and the interrupt to run > continuously. If I recall correctly, this is an external-to-the-CPU thing (wired up by the SoC or the board), which suggests that it ought to be a property on the CPU object (or perhaps on a currently-nonexistent container object which has the CPU and the NVIC and the other M profile devices). As the code stands today, I think the answer is that the board has to set the global -- this is what stellaris.c does. thanks -- PMM
diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c index 06d8db6..c15841e 100644 --- a/hw/intc/armv7m_nvic.c +++ b/hw/intc/armv7m_nvic.c @@ -70,7 +70,7 @@ static const uint8_t nvic_id[] = { #define SYSTICK_CLKSOURCE (1 << 2) #define SYSTICK_COUNTFLAG (1 << 16) -int system_clock_scale; +int system_clock_scale = SYSTICK_SCALE; /* Conversion factor from qemu timer to SysTick frequencies. */ static inline int64_t systick_scale(nvic_state *s)