libpayload: add timer driver for cygnus

BUG=chrome-os-partner:36011
BRANCH=broadcom-firmware
TEST=measured 10 seconds in depthcharge:

Starting depthcharge on purin...
dpch: time 10
 9 8 7 6 5 4 3 2 1 0

Change-Id: I0bcb01c255b19518bb8440111ac81f056c07ed69
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: f5993bd400dd5d38e62d07bc8ce3513175e0d518
Original-Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Original-Reviewed-on: https://chrome-internal-review.googlesource.com/200569
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Commit-Queue: Daisuke Nojiri <dnojiri@google.com>
Original-Tested-by: Daisuke Nojiri <dnojiri@google.com>
Original-Change-Id: Id83aae29cec6320d897e0b231d023a9ee885903e
Original-Reviewed-on: https://chromium-review.googlesource.com/256415
Reviewed-on: http://review.coreboot.org/9850
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 29 insertions, 2 deletions

diff --git a/payloads/libpayload/drivers/timer/cygnus.c b/payloads/libpayload/drivers/timer/cygnus.c
index 16035496b9..e627d3e532 100644
--- a/payloads/libpayload/drivers/timer/cygnus.c
+++ b/payloads/libpayload/drivers/timer/cygnus.c
@@ -18,12 +18,39 @@
  */
 #include <libpayload.h>
 
+struct cygnus_timer {
+	u32 gtim_glob_low;
+	u32 gtim_glob_hi;
+	u32 gtim_glob_ctrl;
+};
+
+static struct cygnus_timer * const timer_ptr =
+		(void *)CONFIG_LP_IPROC_PERIPH_GLB_TIM_REG_BASE;
+
 uint64_t timer_hz(void)
 {
-	return 0;
+	/*
+	 * this is set up by coreboot as follows:
+	 *
+	 * PERIPH_CLOCK /
+	 * (((TIMER_GLB_TIM_CTRL_PRESC & TIMER_GLB_TIM_CTRL_PRESC_MASK)>>8) + 1)
+	 *
+	 * where PERIPH_CLOCK is typically 500000000.
+	 */
+	return 500000000;
 }
 
 uint64_t timer_raw_value(void)
 {
-	return 0;
+	uint64_t cur_tick;
+	uint32_t count_h;
+	uint32_t count_l;
+
+	do {
+		count_h = readl(&timer_ptr->gtim_glob_hi);
+		count_l = readl(&timer_ptr->gtim_glob_low);
+		cur_tick = readl(&timer_ptr->gtim_glob_hi);
+	} while (cur_tick != count_h);
+
+	return (cur_tick << 32) + count_l;
 }