ARM: 9480/1: entry: expand comment in __switch_tografted

As per discussion between the developers in the mail thread
linked, expand the comment in __switch_to so that readers
of the code understand what is going on.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 44 insertions, 0 deletions

diff --git a/include/clocksource/timer-davinci.h b/include/clocksource/timer-davinci.h
new file mode 100644
index 000000000..1dcc1333f
--- /dev/null
+++ b/include/clocksource/timer-davinci.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * TI DaVinci clocksource driver
+ *
+ * Copyright (C) 2019 Texas Instruments
+ * Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
+ */
+
+#ifndef __TIMER_DAVINCI_H__
+#define __TIMER_DAVINCI_H__
+
+#include <linux/clk.h>
+#include <linux/ioport.h>
+
+enum {
+	DAVINCI_TIMER_CLOCKEVENT_IRQ,
+	DAVINCI_TIMER_CLOCKSOURCE_IRQ,
+	DAVINCI_TIMER_NUM_IRQS,
+};
+
+/**
+ * struct davinci_timer_cfg - davinci clocksource driver configuration struct
+ * @reg:        register range resource
+ * @irq:        clockevent and clocksource interrupt resources
+ * @cmp_off:    if set - it specifies the compare register used for clockevent
+ *
+ * Note: if the compare register is specified, the driver will use the bottom
+ * clock half for both clocksource and clockevent and the compare register
+ * to generate event irqs. The user must supply the correct compare register
+ * interrupt number.
+ *
+ * This is only used by da830 the DSP of which uses the top half. The timer
+ * driver still configures the top half to run in free-run mode.
+ */
+struct davinci_timer_cfg {
+	struct resource reg;
+	struct resource irq[DAVINCI_TIMER_NUM_IRQS];
+	unsigned int cmp_off;
+};
+
+int __init davinci_timer_register(struct clk *clk,
+				  const struct davinci_timer_cfg *data);
+
+#endif /* __TIMER_DAVINCI_H__ */