soc/ti/am335x: Fix timer implementation
Implements the monotonic timer using the am335x dmtimer peripheral.
Change-Id: I4736b6d3b6e26370be9e8f369fc02285ad519223
Signed-off-by: Sam Lewis <sam.vr.lewis@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44383
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/ti/am335x/Makefile.inc b/src/soc/ti/am335x/Makefile.inc
index e744c72..60e00fb 100644
--- a/src/soc/ti/am335x/Makefile.inc
+++ b/src/soc/ti/am335x/Makefile.inc
@@ -1,18 +1,15 @@
ifeq ($(CONFIG_SOC_TI_AM335X),y)
bootblock-y += bootblock.c
bootblock-y += bootblock_media.c
-bootblock-y += dmtimer.c
+bootblock-y += timer.c
bootblock-y += gpio.c
bootblock-y += pinmux.c
-bootblock-y += monotonic_timer.c
romstage-y += nand.c
romstage-y += cbmem.c
-romstage-y += dmtimer.c
-romstage-y += monotonic_timer.c
+romstage-y += timer.c
-ramstage-y += dmtimer.c
-ramstage-y += monotonic_timer.c
+ramstage-y += timer.c
ramstage-y += nand.c
ramstage-y += soc.c
diff --git a/src/soc/ti/am335x/dmtimer.c b/src/soc/ti/am335x/dmtimer.c
deleted file mode 100644
index b3aa7a1..0000000
--- a/src/soc/ti/am335x/dmtimer.c
+++ /dev/null
@@ -1,12 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-
-#include "dmtimer.h"
-
-void dmtimer_start(int num)
-{
-}
-
-uint64_t dmtimer_raw_value(int num)
-{
- return 0;
-}
diff --git a/src/soc/ti/am335x/dmtimer.h b/src/soc/ti/am335x/dmtimer.h
index ad8515f..56f3d0f 100644
--- a/src/soc/ti/am335x/dmtimer.h
+++ b/src/soc/ti/am335x/dmtimer.h
@@ -5,9 +5,33 @@
#include <stdint.h>
-#define OSC_HZ 24000000
+#define M_OSC_MHZ (24)
-void dmtimer_start(int num);
-uint64_t dmtimer_raw_value(int num);
+struct am335x_dmtimer {
+ uint32_t tidr;
+ uint8_t res1[12];
+ uint32_t tiocp_cfg;
+ uint8_t res2[12];
+ uint32_t irq_eoi;
+ uint32_t irqstatus_raw;
+ uint32_t irqstatus;
+ uint32_t irqenable_set;
+ uint32_t irqenable_clr;
+ uint32_t irqwakeen;
+ uint32_t tclr;
+ uint32_t tcrr;
+ uint32_t tldr;
+ uint32_t ttgr;
+ uint32_t twps;
+ uint32_t tmar;
+ uint32_t tcar1;
+ uint32_t tsicr;
+ uint32_t tcar2;
+};
+
+#define TCLR_ST (0x01 << 0)
+#define TCLR_AR (0x01 << 1)
+
+#define DMTIMER_2 (0x48040000)
#endif
diff --git a/src/soc/ti/am335x/monotonic_timer.c b/src/soc/ti/am335x/monotonic_timer.c
deleted file mode 100644
index b57258b..0000000
--- a/src/soc/ti/am335x/monotonic_timer.c
+++ /dev/null
@@ -1,40 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-
-#include <stdint.h>
-#include <delay.h>
-#include <timer.h>
-
-#include "dmtimer.h"
-
-static struct monotonic_counter {
- int initialized;
- struct mono_time time;
- uint64_t last_value;
-} mono_counter;
-
-static const uint32_t clocks_per_usec = OSC_HZ/1000000;
-
-void timer_monotonic_get(struct mono_time *mt)
-{
- uint64_t current_tick;
- uint64_t usecs_elapsed;
-
- if (!mono_counter.initialized) {
- init_timer();
- mono_counter.last_value = dmtimer_raw_value(0);
- mono_counter.initialized = 1;
- }
-
- current_tick = dmtimer_raw_value(0);
- usecs_elapsed = (current_tick - mono_counter.last_value) /
- clocks_per_usec;
-
- /* Update current time and tick values only if a full tick occurred. */
- if (usecs_elapsed) {
- mono_time_add_usecs(&mono_counter.time, usecs_elapsed);
- mono_counter.last_value = current_tick;
- }
-
- /* Save result. */
- *mt = mono_counter.time;
-}
diff --git a/src/soc/ti/am335x/timer.c b/src/soc/ti/am335x/timer.c
new file mode 100644
index 0000000..4ed98a3
--- /dev/null
+++ b/src/soc/ti/am335x/timer.c
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <timer.h>
+#include <delay.h>
+#include <device/mmio.h>
+
+#include "dmtimer.h"
+#include "clock.h"
+
+struct am335x_dmtimer *dmtimer_2 = (struct am335x_dmtimer *)DMTIMER_2;
+
+#define CLKSEL_M_OSC (0x01 << 0)
+
+static uint32_t timer_raw_value(void)
+{
+ return read32(&dmtimer_2->tcrr);
+}
+
+void timer_monotonic_get(struct mono_time *mt)
+{
+ mono_time_set_usecs(mt, timer_raw_value() / M_OSC_MHZ);
+}
+
+void init_timer(void)
+{
+ write32(&am335x_cm_dpll->clksel_timer2_clk, CLKSEL_M_OSC);
+
+ // Start the dmtimer in autoreload mode without any prescalers
+ // With M_OSC at 24MHz, this gives a few minutes before the timer overflows
+ write32(&dmtimer_2->tclr, TCLR_ST | TCLR_AR);
+}