pistachio: implement timer support
C0_COUNT register is a free running counter clocked by the CPU
frequency divided by two. On the FPGA board it results in 25 MHz, on
real SOCs it will have to be figured out later.
Some magic addresses and numbers are used to find out if the code is
running on the FPGA board.
timestamp_get() and timer_monotonic_get() are kept in the same file.
The CPU initialization makes sure that CO COUNT is in fact enabled and
starts from zero.
BRANCH=none
BUG=chrome-os-partner:33595,chrome-os-partner:31438
TEST=with timer enabled, the startup code properly initializes UART
and prints the coreboot bootblock banner message on the serial
console.
Change-Id: I98fe330b961f677448b222917ab7d586494ed4b7
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: a7324221c1d856ac72fa2b0ab586b5ea8cab3a05
Original-Change-Id: I2d518213de939e91a35f8aea174aed76d297dd72
Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/227888
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9188
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/src/soc/imgtec/pistachio/bootblock.c b/src/soc/imgtec/pistachio/bootblock.c
index f6cc76b..9011264 100644
--- a/src/soc/imgtec/pistachio/bootblock.c
+++ b/src/soc/imgtec/pistachio/bootblock.c
@@ -19,6 +19,21 @@
* MA 02110-1301 USA
*/
+#include <stdint.h>
+#include <arch/cpu.h>
+
static void bootblock_cpu_init(void)
{
+ uint32_t cause;
+
+ /*
+ * Make sure the count register is counting by clearing the "Disable
+ * Counter" bit, in case it is set.
+ */
+ cause = read_c0_cause();
+ if (cause & C0_CAUSE_DC)
+ write_c0_cause(cause & ~(C0_CAUSE_DC));
+
+ /* And make sure that it starts from zero. */
+ write_c0_count(0);
}