/*
* Interrupt handling for GE FPGA based PIC
*
* Author: Martyn Welch <martyn.welch@ge.com>
*
* 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/irq.h>
#include "gef_pic.h"
#define DEBUG
#undef DEBUG
#ifdef DEBUG
#define DBG(fmt...) do { printk(KERN_DEBUG "gef_pic: " fmt); } while (0)
#else
#define DBG(fmt...) do { } while (0)
#endif
#define GEF_PIC_NUM_IRQS 32
/* Interrupt Controller Interface Registers */
#define GEF_PIC_INTR_STATUS 0x0000
#define GEF_PIC_INTR_MASK(cpu) (0x0010 + (0x4 * cpu))
#define GEF_PIC_CPU0_INTR_MASK GEF_PIC_INTR_MASK(0)
#define GEF_PIC_CPU1_INTR_MASK GEF_PIC_INTR_MASK(1)
#define GEF_PIC_MCP_MASK(cpu) (0x0018 + (0x4 * cpu))
#define GEF_PIC_CPU0_MCP_MASK GEF_PIC_MCP_MASK(0)
#define GEF_PIC_CPU1_MCP_MASK GEF_PIC_MCP_MASK(1)
#define gef_irq_to_hw(virq) ((unsigned int)irq_map[virq].hwirq)
static DEFINE_RAW_SPINLOCK(gef_pic_lock);
static void __iomem *gef_pic_irq_reg_base;
static struct irq_host *gef_pic_irq_host;
static int gef_pic_cascade_irq;
/*
* Interrupt Controller Handling
*
* The interrupt controller handles interrupts for most on board interrupts,
* apart from PCI interrupts. For example on SBC610:
*
* 17:31 RO Reserved
* 16 RO PCI Express Doorbell 3 Status
* 15 RO PCI Express Doorbell 2 Status
* 14 RO PCI Express Doorbell 1 Status
* 13 RO PCI Express Doorbell 0 Status
* 12 RO Real Time Clock Interrupt Status
* 11 RO Temperature Interrupt Status
* 10 RO Temperature Critical Interrupt Status
* 9 RO Ethernet PHY1 Interrupt Status
* 8 RO Ethernet PHY3 Interrupt Status
* 7 RO PEX8548 Interrupt Status
* 6 RO Reserved
* 5 RO Watchdog 0 Interrupt Status
* 4 RO Watchdog 1 Interrupt Status
* 3 RO AXIS Message FIFO A Interrupt Status
* 2 RO AXIS Message FIFO B Interrupt Status
* 1 RO AXIS Message FIFO C Interrupt Status
* 0 RO AXIS Message FIFO D Interrupt Status
*
* Interrupts can be forwarded to one of two output lines. Nothing
* clever is done, so if the masks are incorrectly set, a single input
* interrupt could generate interrupts on both output lines!
*
* The dual lines are there to allow the chained interrupts to be easily
* passed into two different cores. We currently do not use this functionality
* in this driver.
*
* Controller can also be configured to generate Machine checks (MCP), again on
* two lines, to be attached to two different cores. It is suggested that these
* should be masked out.
*/
void gef_pic_cascade(unsigned int irq, struct irq_desc *desc)
{
unsigned int cascade_irq;
/*
* See if we actually have an interrupt, call generic handling code if
* we do.
*/
cascade_irq = gef_pic_get_irq();
if (cascade_irq != NO_IRQ)
generic_handle_irq(cascade_irq);
desc->chip->eoi(irq);
}
static void gef_pic_mask(unsigned int virq)
{
unsigned long flags;
unsigned int hwirq;
u32 mask;
hwirq = gef_irq_to_hw(virq);
raw_spin_lock_irqsave(&gef_pic_lock, flags);
mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
mask &= ~(1 << hwirq);
out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask);
raw_spin_unlock_irqrestore(&gef_pic_lock, flags);
}
static void gef_pic_mask_ack(unsigned int virq)
{
/* Don't think we actually have to do anything to ack an interrupt,
* we just need to clear down the devices interrupt and it will go away
*/
gef_pic_mask(virq);
}
static void gef_pic_unmask(unsigned int virq)
{
unsigned long flags;
unsigned int hwirq;
u32 mask;
hwirq = gef_irq_to_hw(virq);
raw_spin_lock_irqsave(&gef_pic_lock, flags);
mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
mask |= (1 << hwirq);
out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask);
raw_spin_unlock_irqrestore(&gef_pic_lock, flags);
}
static struct irq_chip gef_pic_chip = {
.name = "gefp",
.mask = gef_pic_mask,
.mask_ack = gef_pic_mask_ack,
.unmask = gef_pic_unmask,
};
/* When an interrupt is being configured, this call allows some flexibilty
* in deciding which irq_chip structure is used
*/
static int gef_pic_host_map(struct irq_host *h, unsigned int virq,
irq_hw_number_t hwirq)
{
/* All interrupts are LEVEL sensitive */
irq_to_desc(virq)->status |= IRQ_LEVEL;
set_irq_chip_and_handler(virq, &gef_pic_chip, handle_level_irq);
return 0;
}
static int gef_pic_host_xlate(struct irq_host *h, struct device_node *ct,
const u32 *intspec, unsigned int intsize,
irq_hw_number_t *out_hwirq, unsigned int *out_flags)
{
*out_hwirq = intspec[0];
if (intsize > 1)
*out_flags = intspec[1];
else
*out_flags = IRQ_TYPE_LEVEL_HIGH;
return 0;
}
static struct irq_host_ops gef_pic_host_ops = {
.map = gef_pic_host_map,
.xlate = gef_pic_host_xlate,
};
/*
* Initialisation of PIC, this should be called in BSP
*/
void __init gef_pic_init(struct device_node *np)
{
unsigned long flags;
/* Map the devices registers into memory */
gef_pic_irq_reg_base = of_iomap(np, 0);
raw_spin_lock_irqsave(&gef_pic_lock, flags);
/* Initialise everything as masked. */
out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_INTR_MASK, 0);
out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_INTR_MASK, 0);
out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_MCP_MASK, 0);
out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_MCP_MASK, 0);
raw_spin_unlock_irqrestore(&gef_pic_lock, flags);
/* Map controller */
gef_pic_cascade_irq = irq_of_parse_and_map(np, 0);
if (gef_pic_cascade_irq == NO_IRQ) {
printk(KERN_ERR "SBC610: failed to map cascade interrupt");
return;
}
/* Setup an irq_host structure */
gef_pic_irq_host = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR,
GEF_PIC_NUM_IRQS,
&gef_pic_host_ops, NO_IRQ);
if (gef_pic_irq_host == NULL)
return;
/* Chain with parent controller */
set_irq_chained_handler(gef_pic_cascade_irq, gef_pic_cascade);
}
/*
* This is called when we receive an interrupt with apparently comes from this
* chip - check, returning the highest interrupt generated or return NO_IRQ
*/
unsigned int gef_pic_get_irq(void)
{
u32 cause, mask, active;
unsigned int virq = NO_IRQ;
int hwirq;
cause = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_STATUS);
mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
active = cause & mask;
if (active) {
for (hwirq = GEF_PIC_NUM_IRQS - 1; hwirq > -1; hwirq--) {
if (active & (0x1 << hwirq))
break;
}
virq = irq_linear_revmap(gef_pic_irq_host,
(irq_hw_number_t)hwirq);
}
return virq;
}
