powerpc/mpic: add global timer support

The MPIC global timer is a hardware timer inside the Freescale PIC complying
with OpenPIC standard. When the specified interval times out, the hardware
timer generates an interrupt. The driver currently is only tested on fsl chip,
but it can potentially support other global timers complying to OpenPIC
standard.

The two independent groups of global timer on fsl chip, group A and group B,
are identical in their functionality, except that they appear at different
locations within the PIC register map. The hardware timer can be cascaded to
create timers larger than the default 31-bit global timers. Timer cascade
fields allow configuration of up to two 63-bit timers. But These two groups
of timers cannot be cascaded together.

It can be used as a wakeup source for low power modes. It also could be used
as periodical timer for protocols, drivers and etc.
Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>

arch/powerpc/include/asm/mpic_timer.h

+/*
+ * 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 modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at 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 *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 *time) { }
+void mpic_free_timer(struct mpic_timer *handle) { }
+#endif
+
+#endif

arch/powerpc/platforms/Kconfig

@@ -86,6 +86,18 @@ config MPIC
 	bool
 	default n
 
+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 complying with OpenPIC standard. When the
+	  specified interval times out, the hardware timer generates
+	  an interrupt. The driver currently is only tested on fsl
+	  chip, but it can potentially support other global timers
+	  complying with the OpenPIC standard.
+
 config PPC_EPAPR_HV_PIC
 	bool
 	default n

arch/powerpc/sysdev/Makefile

@@ -4,6 +4,7 @@ ccflags-$(CONFIG_PPC64)		:= $(NO_MINIMAL_TOC)
 
 mpic-msi-obj-$(CONFIG_PCI_MSI)	+= mpic_msi.o mpic_u3msi.o mpic_pasemi_msi.o
 obj-$(CONFIG_MPIC)		+= mpic.o $(mpic-msi-obj-y)
+obj-$(CONFIG_MPIC_TIMER)        += mpic_timer.o
 mpic-msgr-obj-$(CONFIG_MPIC_MSGR)	+= mpic_msgr.o
 obj-$(CONFIG_MPIC)		+= mpic.o $(mpic-msi-obj-y) $(mpic-msgr-obj-y)
 obj-$(CONFIG_PPC_EPAPR_HV_PIC)	+= ehv_pic.o