linux/arch/powerpc/platforms/wsp/opb_pic.c
Thomas Gleixner 5f20b85dc2 powerpc/wsp: Mark opb cascade handler IRQF_NO_THREAD
Cascade handlers must run in hard interrupt context.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-25 14:11:29 +11:00

334 lines
7.5 KiB
C

/*
* IBM Onboard Peripheral Bus Interrupt Controller
*
* Copyright 2010 Jack Miller, IBM Corporation.
*
* 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.
*/
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <asm/reg_a2.h>
#include <asm/irq.h>
#define OPB_NR_IRQS 32
#define OPB_MLSASIER 0x04 /* MLS Accumulated Status IER */
#define OPB_MLSIR 0x50 /* MLS Interrupt Register */
#define OPB_MLSIER 0x54 /* MLS Interrupt Enable Register */
#define OPB_MLSIPR 0x58 /* MLS Interrupt Polarity Register */
#define OPB_MLSIIR 0x5c /* MLS Interrupt Inputs Register */
static int opb_index = 0;
struct opb_pic {
struct irq_host *host;
void *regs;
int index;
spinlock_t lock;
};
static u32 opb_in(struct opb_pic *opb, int offset)
{
return in_be32(opb->regs + offset);
}
static void opb_out(struct opb_pic *opb, int offset, u32 val)
{
out_be32(opb->regs + offset, val);
}
static void opb_unmask_irq(struct irq_data *d)
{
struct opb_pic *opb;
unsigned long flags;
u32 ier, bitset;
opb = d->chip_data;
bitset = (1 << (31 - irqd_to_hwirq(d)));
spin_lock_irqsave(&opb->lock, flags);
ier = opb_in(opb, OPB_MLSIER);
opb_out(opb, OPB_MLSIER, ier | bitset);
ier = opb_in(opb, OPB_MLSIER);
spin_unlock_irqrestore(&opb->lock, flags);
}
static void opb_mask_irq(struct irq_data *d)
{
struct opb_pic *opb;
unsigned long flags;
u32 ier, mask;
opb = d->chip_data;
mask = ~(1 << (31 - irqd_to_hwirq(d)));
spin_lock_irqsave(&opb->lock, flags);
ier = opb_in(opb, OPB_MLSIER);
opb_out(opb, OPB_MLSIER, ier & mask);
ier = opb_in(opb, OPB_MLSIER); // Flush posted writes
spin_unlock_irqrestore(&opb->lock, flags);
}
static void opb_ack_irq(struct irq_data *d)
{
struct opb_pic *opb;
unsigned long flags;
u32 bitset;
opb = d->chip_data;
bitset = (1 << (31 - irqd_to_hwirq(d)));
spin_lock_irqsave(&opb->lock, flags);
opb_out(opb, OPB_MLSIR, bitset);
opb_in(opb, OPB_MLSIR); // Flush posted writes
spin_unlock_irqrestore(&opb->lock, flags);
}
static void opb_mask_ack_irq(struct irq_data *d)
{
struct opb_pic *opb;
unsigned long flags;
u32 bitset;
u32 ier, ir;
opb = d->chip_data;
bitset = (1 << (31 - irqd_to_hwirq(d)));
spin_lock_irqsave(&opb->lock, flags);
ier = opb_in(opb, OPB_MLSIER);
opb_out(opb, OPB_MLSIER, ier & ~bitset);
ier = opb_in(opb, OPB_MLSIER); // Flush posted writes
opb_out(opb, OPB_MLSIR, bitset);
ir = opb_in(opb, OPB_MLSIR); // Flush posted writes
spin_unlock_irqrestore(&opb->lock, flags);
}
static int opb_set_irq_type(struct irq_data *d, unsigned int flow)
{
struct opb_pic *opb;
unsigned long flags;
int invert, ipr, mask, bit;
opb = d->chip_data;
/* The only information we're interested in in the type is whether it's
* a high or low trigger. For high triggered interrupts, the polarity
* set for it in the MLS Interrupt Polarity Register is 0, for low
* interrupts it's 1 so that the proper input in the MLS Interrupt Input
* Register is interrupted as asserting the interrupt. */
switch (flow) {
case IRQ_TYPE_NONE:
opb_mask_irq(d);
return 0;
case IRQ_TYPE_LEVEL_HIGH:
invert = 0;
break;
case IRQ_TYPE_LEVEL_LOW:
invert = 1;
break;
default:
return -EINVAL;
}
bit = (1 << (31 - irqd_to_hwirq(d)));
mask = ~bit;
spin_lock_irqsave(&opb->lock, flags);
ipr = opb_in(opb, OPB_MLSIPR);
ipr = (ipr & mask) | (invert ? bit : 0);
opb_out(opb, OPB_MLSIPR, ipr);
ipr = opb_in(opb, OPB_MLSIPR); // Flush posted writes
spin_unlock_irqrestore(&opb->lock, flags);
/* Record the type in the interrupt descriptor */
irqd_set_trigger_type(d, flow);
return 0;
}
static struct irq_chip opb_irq_chip = {
.name = "OPB",
.irq_mask = opb_mask_irq,
.irq_unmask = opb_unmask_irq,
.irq_mask_ack = opb_mask_ack_irq,
.irq_ack = opb_ack_irq,
.irq_set_type = opb_set_irq_type
};
static int opb_host_map(struct irq_host *host, unsigned int virq,
irq_hw_number_t hwirq)
{
struct opb_pic *opb;
opb = host->host_data;
/* Most of the important stuff is handled by the generic host code, like
* the lookup, so just attach some info to the virtual irq */
irq_set_chip_data(virq, opb);
irq_set_chip_and_handler(virq, &opb_irq_chip, handle_level_irq);
irq_set_irq_type(virq, IRQ_TYPE_NONE);
return 0;
}
static int opb_host_xlate(struct irq_host *host, struct device_node *dn,
const u32 *intspec, unsigned int intsize,
irq_hw_number_t *out_hwirq, unsigned int *out_type)
{
/* Interrupt size must == 2 */
BUG_ON(intsize != 2);
*out_hwirq = intspec[0];
*out_type = intspec[1];
return 0;
}
static struct irq_host_ops opb_host_ops = {
.map = opb_host_map,
.xlate = opb_host_xlate,
};
irqreturn_t opb_irq_handler(int irq, void *private)
{
struct opb_pic *opb;
u32 ir, src, subvirq;
opb = (struct opb_pic *) private;
/* Read the OPB MLS Interrupt Register for
* asserted interrupts */
ir = opb_in(opb, OPB_MLSIR);
if (!ir)
return IRQ_NONE;
do {
/* Get 1 - 32 source, *NOT* bit */
src = 32 - ffs(ir);
/* Translate from the OPB's conception of interrupt number to
* Linux's virtual IRQ */
subvirq = irq_linear_revmap(opb->host, src);
generic_handle_irq(subvirq);
} while ((ir = opb_in(opb, OPB_MLSIR)));
return IRQ_HANDLED;
}
struct opb_pic *opb_pic_init_one(struct device_node *dn)
{
struct opb_pic *opb;
struct resource res;
if (of_address_to_resource(dn, 0, &res)) {
printk(KERN_ERR "opb: Couldn't translate resource\n");
return NULL;
}
opb = kzalloc(sizeof(struct opb_pic), GFP_KERNEL);
if (!opb) {
printk(KERN_ERR "opb: Failed to allocate opb struct!\n");
return NULL;
}
/* Get access to the OPB MMIO registers */
opb->regs = ioremap(res.start + 0x10000, 0x1000);
if (!opb->regs) {
printk(KERN_ERR "opb: Failed to allocate register space!\n");
goto free_opb;
}
/* Allocate an irq host so that Linux knows that despite only
* having one interrupt to issue, we're the controller for multiple
* hardware IRQs, so later we can lookup their virtual IRQs. */
opb->host = irq_alloc_host(dn, IRQ_HOST_MAP_LINEAR,
OPB_NR_IRQS, &opb_host_ops, -1);
if (!opb->host) {
printk(KERN_ERR "opb: Failed to allocate IRQ host!\n");
goto free_regs;
}
opb->index = opb_index++;
spin_lock_init(&opb->lock);
opb->host->host_data = opb;
/* Disable all interrupts by default */
opb_out(opb, OPB_MLSASIER, 0);
opb_out(opb, OPB_MLSIER, 0);
/* ACK any interrupts left by FW */
opb_out(opb, OPB_MLSIR, 0xFFFFFFFF);
return opb;
free_regs:
iounmap(opb->regs);
free_opb:
kfree(opb);
return NULL;
}
void __init opb_pic_init(void)
{
struct device_node *dn;
struct opb_pic *opb;
int virq;
int rc;
/* Call init_one for each OPB device */
for_each_compatible_node(dn, NULL, "ibm,opb") {
/* Fill in an OPB struct */
opb = opb_pic_init_one(dn);
if (!opb) {
printk(KERN_WARNING "opb: Failed to init node, skipped!\n");
continue;
}
/* Map / get opb's hardware virtual irq */
virq = irq_of_parse_and_map(dn, 0);
if (virq <= 0) {
printk("opb: irq_op_parse_and_map failed!\n");
continue;
}
/* Attach opb interrupt handler to new virtual IRQ */
rc = request_irq(virq, opb_irq_handler, IRQF_NO_THREAD,
"OPB LS Cascade", opb);
if (rc) {
printk("opb: request_irq failed: %d\n", rc);
continue;
}
printk("OPB%d init with %d IRQs at %p\n", opb->index,
OPB_NR_IRQS, opb->regs);
}
}