v4.19.13 snapshot.
diff --git a/drivers/clocksource/clksrc-dbx500-prcmu.c b/drivers/clocksource/clksrc-dbx500-prcmu.c
new file mode 100644
index 0000000..c1b96dc
--- /dev/null
+++ b/drivers/clocksource/clksrc-dbx500-prcmu.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ *
+ * License Terms: GNU General Public License v2
+ * Author: Mattias Wallin <mattias.wallin@stericsson.com> for ST-Ericsson
+ * Author: Sundar Iyer for ST-Ericsson
+ * sched_clock implementation is based on:
+ * plat-nomadik/timer.c Linus Walleij <linus.walleij@stericsson.com>
+ *
+ * DBx500-PRCMU Timer
+ * The PRCMU has 5 timers which are available in a always-on
+ * power domain. We use the Timer 4 for our always-on clock
+ * source on DB8500.
+ */
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clockchips.h>
+#include <linux/sched_clock.h>
+
+#define RATE_32K 32768
+
+#define TIMER_MODE_CONTINOUS 0x1
+#define TIMER_DOWNCOUNT_VAL 0xffffffff
+
+#define PRCMU_TIMER_REF 0
+#define PRCMU_TIMER_DOWNCOUNT 0x4
+#define PRCMU_TIMER_MODE 0x8
+
+#define SCHED_CLOCK_MIN_WRAP 131072 /* 2^32 / 32768 */
+
+static void __iomem *clksrc_dbx500_timer_base;
+
+static u64 notrace clksrc_dbx500_prcmu_read(struct clocksource *cs)
+{
+ void __iomem *base = clksrc_dbx500_timer_base;
+ u32 count, count2;
+
+ do {
+ count = readl_relaxed(base + PRCMU_TIMER_DOWNCOUNT);
+ count2 = readl_relaxed(base + PRCMU_TIMER_DOWNCOUNT);
+ } while (count2 != count);
+
+ /* Negate because the timer is a decrementing counter */
+ return ~count;
+}
+
+static struct clocksource clocksource_dbx500_prcmu = {
+ .name = "dbx500-prcmu-timer",
+ .rating = 300,
+ .read = clksrc_dbx500_prcmu_read,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+#ifdef CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK
+
+static u64 notrace dbx500_prcmu_sched_clock_read(void)
+{
+ if (unlikely(!clksrc_dbx500_timer_base))
+ return 0;
+
+ return clksrc_dbx500_prcmu_read(&clocksource_dbx500_prcmu);
+}
+
+#endif
+
+static int __init clksrc_dbx500_prcmu_init(struct device_node *node)
+{
+ clksrc_dbx500_timer_base = of_iomap(node, 0);
+
+ /*
+ * The A9 sub system expects the timer to be configured as
+ * a continous looping timer.
+ * The PRCMU should configure it but if it for some reason
+ * don't we do it here.
+ */
+ if (readl(clksrc_dbx500_timer_base + PRCMU_TIMER_MODE) !=
+ TIMER_MODE_CONTINOUS) {
+ writel(TIMER_MODE_CONTINOUS,
+ clksrc_dbx500_timer_base + PRCMU_TIMER_MODE);
+ writel(TIMER_DOWNCOUNT_VAL,
+ clksrc_dbx500_timer_base + PRCMU_TIMER_REF);
+ }
+#ifdef CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK
+ sched_clock_register(dbx500_prcmu_sched_clock_read, 32, RATE_32K);
+#endif
+ return clocksource_register_hz(&clocksource_dbx500_prcmu, RATE_32K);
+}
+TIMER_OF_DECLARE(dbx500_prcmu, "stericsson,db8500-prcmu-timer-4",
+ clksrc_dbx500_prcmu_init);