ARM: OMAP: PRCM: add support for chain interrupt handler

Introduce a chained interrupt handler mechanism for the PRCM
interrupt, so that individual PRCM event can cleanly be handled by
handlers in separate drivers. We do this by introducing PRCM event
names, which are then matched to the particular PRCM interrupt bit
depending on the specific OMAP SoC being used.

PRCM interrupts have two priority levels, high or normal. High priority
is needed for IO event handling, so that we can be sure that IO events
are processed before other events. This reduces latency for IO event
customers and also prevents incorrect ack sequence on OMAP3.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Avinash.H.M <avinashhm@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Govindraj.R <govindraj.raja@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
[paul@pwsan.com: drop some dead code; use SoC-specific pending IRQ
 detection; move code to prm_common.c; add lots of documentation;
 remove saved_mask; add OCP barrier on ISR exit; improved error
 handling; split out per-SoC initialization to a separate patch]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

1 files changed, 62 insertions, 1 deletions

diff --git a/arch/arm/mach-omap2/prcm-common.h b/arch/arm/mach-omap2/prcm-common.h
index 0363dcb..76db379 100644
--- a/arch/arm/mach-omap2/prcm-common.h
+++ b/arch/arm/mach-omap2/prcm-common.h
@@ -4,7 +4,7 @@
 /*
  * OMAP2/3 PRCM base and module definitions
  *
- * Copyright (C) 2007-2009 Texas Instruments, Inc.
+ * Copyright (C) 2007-2009, 2011 Texas Instruments, Inc.
  * Copyright (C) 2007-2009 Nokia Corporation
  *
  * Written by Paul Walmsley
@@ -408,6 +408,67 @@
 extern void __iomem *prm_base;
 extern void __iomem *cm_base;
 extern void __iomem *cm2_base;
+
+/**
+ * struct omap_prcm_irq - describes a PRCM interrupt bit
+ * @name: a short name describing the interrupt type, e.g. "wkup" or "io"
+ * @offset: the bit shift of the interrupt inside the IRQ{ENABLE,STATUS} regs
+ * @priority: should this interrupt be handled before @priority=false IRQs?
+ *
+ * Describes interrupt bits inside the PRM_IRQ{ENABLE,STATUS}_MPU* registers.
+ * On systems with multiple PRM MPU IRQ registers, the bitfields read from
+ * the registers are concatenated, so @offset could be > 31 on these systems -
+ * see omap_prm_irq_handler() for more details.  I/O ring interrupts should
+ * have @priority set to true.
+ */
+struct omap_prcm_irq {
+	const char *name;
+	unsigned int offset;
+	bool priority;
+};
+
+/**
+ * struct omap_prcm_irq_setup - PRCM interrupt controller details
+ * @ack: PRM register offset for the first PRM_IRQSTATUS_MPU register
+ * @mask: PRM register offset for the first PRM_IRQENABLE_MPU register
+ * @nr_regs: number of PRM_IRQ{STATUS,ENABLE}_MPU* registers
+ * @nr_irqs: number of entries in the @irqs array
+ * @irqs: ptr to an array of PRCM interrupt bits (see @nr_irqs)
+ * @irq: MPU IRQ asserted when a PRCM interrupt arrives
+ * @read_pending_irqs: fn ptr to determine if any PRCM IRQs are pending
+ * @ocp_barrier: fn ptr to force buffered PRM writes to complete
+ * @priority_mask: 1 bit per IRQ, set to 1 if omap_prcm_irq.priority = true
+ * @base_irq: base dynamic IRQ number, returned from irq_alloc_descs() in init
+ *
+ * @priority_mask and @base_irq are populated dynamically during
+ * omap_prcm_register_chain_handler() - these fields are not to be
+ * specified in static initializers.
+ */
+struct omap_prcm_irq_setup {
+	u16 ack;
+	u16 mask;
+	u8 nr_regs;
+	u8 nr_irqs;
+	const struct omap_prcm_irq *irqs;
+	int irq;
+	void (*read_pending_irqs)(unsigned long *events);
+	void (*ocp_barrier)(void);
+	u32 *priority_mask;
+	int base_irq;
+};
+
+/* OMAP_PRCM_IRQ: convenience macro for creating struct omap_prcm_irq records */
+#define OMAP_PRCM_IRQ(_name, _offset, _priority) {	\
+	.name = _name,					\
+	.offset = _offset,				\
+	.priority = _priority				\
+	}
+
+extern void omap_prcm_irq_cleanup(void);
+extern int omap_prcm_register_chain_handler(
+	struct omap_prcm_irq_setup *irq_setup);
+extern int omap_prcm_event_to_irq(const char *event);
+
 # endif
 
 #endif