2013/1/26 Paul Brook p...@codesourcery.com
The FTAPBBRG020 supports the DMA functions for the AHB-to-AHB,
AHB-to-APB, APB-to-AHB, and APB-to-APB transactions.
All the timer code in this file looks suspect. As a general rule
everything
should be event driven and complete immediately (or at least schedule a BH
for
immediate action if recursion is a concern), not relying on a periodic
timer
interrupts.
Agree,
I've cheated here, because I'm too lazy to checkout how to use mutex/thread
in QEMU,
I'll fix it later.
+qemu_mod_timer(s-qtimer,
+qemu_get_clock_ns(vm_clock) + 1);
For all practical purposes this is going to happen immediately, so you
should
not be using a timer.
+qemu_mod_timer(s-qtimer,
+qemu_get_clock_ns(vm_clock) + (get_ticks_per_sec() 2));
Why 0.25 seconds? Usually this sort of try-again-soon behavior means
you've
missed a trigger event somewhere else.
Yes,
it's because I'm using timer instead of mutext/thread here,
so there might be some race conditions, and thus I added this stupid
work-around here.
+if (!cpu_physical_memory_is_io(c-src)) {
+src_map = src_ptr = cpu_physical_memory_map(c-src, src_len,
0);
+}
+if (!cpu_physical_memory_is_io(c-dst)) {
+dst_map = dst_ptr = cpu_physical_memory_map(c-dst, dst_len,
1);
+}
cpu_physical_memory_map might not map the whole region you requested. This
will cause badness in the subsequent code.
My bad, I forgot this, I'll fix it later.
I suspect a log of this code anc and should be shared with your other DMA
controller, and probably several of the existing DMA controllers.
Paul
--
Best wishes,
Kuo-Jung Su
2013/1/26 Paul Brook p...@codesourcery.com
The FTAPBBRG020 supports the DMA functions for the AHB-to-AHB,
AHB-to-APB, APB-to-AHB, and APB-to-APB transactions.
All the timer code in this file looks suspect. As a general rule
everything
should be event driven and complete immediately (or at least schedule a BH
for
immediate action if recursion is a concern), not relying on a periodic
timer
interrupts.
+qemu_mod_timer(s-qtimer,
+qemu_get_clock_ns(vm_clock) + 1);
For all practical purposes this is going to happen immediately, so you
should
not be using a timer.
+qemu_mod_timer(s-qtimer,
+qemu_get_clock_ns(vm_clock) + (get_ticks_per_sec() 2));
Why 0.25 seconds? Usually this sort of try-again-soon behavior means
you've
missed a trigger event somewhere else.
+if (!cpu_physical_memory_is_io(c-src)) {
+src_map = src_ptr = cpu_physical_memory_map(c-src, src_len,
0);
+}
+if (!cpu_physical_memory_is_io(c-dst)) {
+dst_map = dst_ptr = cpu_physical_memory_map(c-dst, dst_len,
1);
+}
cpu_physical_memory_map might not map the whole region you requested. This
will cause badness in the subsequent code.
I suspect a log of this code anc and should be shared with your other DMA
controller, and probably several of the existing DMA controllers.
Paul
--
Best wishes,
Kuo-Jung Su
