Re: [PATCH 2/3] powerpc/mpic: add global timer support

The MPIC global timer is a hardware timer inside the Freescale PIC =20
comply
to Open-PIC standard. When the timer is timeout of the specified =20
interval,
the hardware timer generates an interrupt. The driver currently is =20
only
tested on fsl chip, but it can potentially support other global timers
complying to Open-PIC standard.
=20
The two independent groups of global timer on fsl chip, group A and =20
group B,
are identical in their functionality, except that they appear at =20
different
locations within the PIC register map. The hardware timer can be =20
cascaded to
create timers larger than the default 31-bit global timers. Timer =20
cascade
fields allow configuration of up to two 63-bit timers. But These two =20
groups
of timers cannot be cascaded together.
=20
It can be used as a wakeup source for low power modes. It also could =20
be used
as periodical timer for protocols, drivers and etc.
=20
Signed-off-by: Wang Dongsheng <redacted>
Signed-off-by: Li Yang <redacted>
---
 arch/powerpc/include/asm/mpic_timer.h |   46 +++
 arch/powerpc/platforms/Kconfig        |   12 +
 arch/powerpc/sysdev/Makefile          |    1 +
 arch/powerpc/sysdev/mpic_timer.c      |  606 =20
+++++++++++++++++++++++++++++++++
 4 files changed, 665 insertions(+), 0 deletions(-)
 create mode 100644 arch/powerpc/include/asm/mpic_timer.h
 create mode 100644 arch/powerpc/sysdev/mpic_timer.c
=20

diff --git a/arch/powerpc/include/asm/mpic_timer.h =20

b/arch/powerpc/include/asm/mpic_timer.h
new file mode 100644
index 0000000..0e23cd4

--- /dev/null
+++ b/arch/powerpc/include/asm/mpic_timer.h

@@ -0,0 +1,46 @@
+/*
+ * arch/powerpc/include/asm/mpic_timer.h
+ *
+ * Header file for Mpic Global Timer
+ *
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * Author: Wang Dongsheng <Dongsheng.Wang@freescale.com>
+ *	   Li Yang <leoli@freescale.com>
+ *
+ * This program is free software; you can redistribute it and/or =20

modify it
+ * under the terms of the GNU General Public License as published by =20
the
+ * Free Software Foundation; either version 2 of the License, or (at =20
your
+ * option) any later version.
+ */
+
+#ifndef __MPIC_TIMER__
+#define __MPIC_TIMER__
+
+#include <linux/interrupt.h>
+#include <linux/time.h>
+
+struct mpic_timer {
+	void			*dev;
+	struct cascade_priv	*cascade_handle;
+	unsigned int		num;
+	unsigned int		irq;
+};
+
+#ifdef CONFIG_MPIC_TIMER
+struct mpic_timer *mpic_request_timer(irq_handler_t fn,  void *dev,
+		const struct timeval *time);
+void mpic_start_timer(struct mpic_timer *handle);
+void mpic_stop_timer(struct mpic_timer *handle);
+void mpic_get_remain_time(struct mpic_timer *handle, struct timeval =20
*time);
+void mpic_free_timer(struct mpic_timer *handle);
+#else
+struct mpic_timer *mpic_request_timer(irq_handler_t fn,  void *dev,
+		const struct timeval *time) { return NULL; }
+void mpic_start_timer(struct mpic_timer *handle) { }
+void mpic_stop_timer(struct mpic_timer *handle) { }
+void mpic_get_remain_time(struct mpic_timer *handle, struct timeval =20
*time) { }
+void mpic_free_timer(struct mpic_timer *handle) { }
+#endif

+config MPIC_TIMER
+	bool "MPIC Global Timer"
+	depends on MPIC && FSL_SOC
+	default n
+	help
+	  The MPIC global timer is a hardware timer inside the
+	  Freescale PIC comply to Open-PIC standard. When the

+	  timer generates an interrupt. The driver currently is
+	  only tested on fsl chip, but it can potentially support
+	  other global timers complying to Open-PIC standard.

+	list_for_each_entry(priv, &timer_group_list, node) {
+		ret =3D convert_time_to_ticks(priv, time, &ticks);
+		if (ret < 0)
+			return NULL;
+
+		if (ticks > MAX_TICKS) {
+			if (!(priv->flags & FSL_GLOBAL_TIMER))
+				return NULL;
+
+			timer =3D get_cascade_timer(priv, ticks);
+			if (!timer)
+				continue;
+			else
+				return timer;
+		}