linux-stable/drivers/irqchip/irq-crossbar.c
Nishanth Menon ddee0fb46d irqchip: crossbar: Change allocation logic by reversing search for free irqs
Reverse the search algorithm to ensure that address mapping and IRQ
allocation logics are proper. This makes the below bugs visible sooner.

class 1. address space errors -> example:
reg = <a size_b>
ti,max-irqs =  is a wrong parameter

class 2: irq-reserved list - which decides which entries in the
address space is not actually wired in

class 3: wrong list of routable-irqs.

In general allocating from max to min tends to have benefits in
ensuring the different issues that may be present in dts is easily
caught at definition time, rather than at a later point in time.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Sricharan R <r.sricharan@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Link: https://lkml.kernel.org/r/1403766634-18543-6-git-send-email-r.sricharan@ti.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
2014-06-30 19:11:21 +00:00

261 lines
5.4 KiB
C

/*
* drivers/irqchip/irq-crossbar.c
*
* Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
* Author: Sricharan R <r.sricharan@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/slab.h>
#include <linux/irqchip/arm-gic.h>
#define IRQ_FREE -1
#define IRQ_RESERVED -2
#define IRQ_SKIP -3
#define GIC_IRQ_START 32
/*
* @int_max: maximum number of supported interrupts
* @safe_map: safe default value to initialize the crossbar
* @irq_map: array of interrupts to crossbar number mapping
* @crossbar_base: crossbar base address
* @register_offsets: offsets for each irq number
*/
struct crossbar_device {
uint int_max;
uint safe_map;
uint *irq_map;
void __iomem *crossbar_base;
int *register_offsets;
void (*write)(int, int);
};
static struct crossbar_device *cb;
static inline void crossbar_writel(int irq_no, int cb_no)
{
writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
}
static inline void crossbar_writew(int irq_no, int cb_no)
{
writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
}
static inline void crossbar_writeb(int irq_no, int cb_no)
{
writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
}
static inline int get_prev_map_irq(int cb_no)
{
int i;
for (i = cb->int_max - 1; i >= 0; i--)
if (cb->irq_map[i] == cb_no)
return i;
return -ENODEV;
}
static inline int allocate_free_irq(int cb_no)
{
int i;
for (i = cb->int_max - 1; i >= 0; i--) {
if (cb->irq_map[i] == IRQ_FREE) {
cb->irq_map[i] = cb_no;
return i;
}
}
return -ENODEV;
}
static int crossbar_domain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hw)
{
cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]);
return 0;
}
static void crossbar_domain_unmap(struct irq_domain *d, unsigned int irq)
{
irq_hw_number_t hw = irq_get_irq_data(irq)->hwirq;
if (hw > GIC_IRQ_START) {
cb->irq_map[hw - GIC_IRQ_START] = IRQ_FREE;
cb->write(hw - GIC_IRQ_START, cb->safe_map);
}
}
static int crossbar_domain_xlate(struct irq_domain *d,
struct device_node *controller,
const u32 *intspec, unsigned int intsize,
unsigned long *out_hwirq,
unsigned int *out_type)
{
unsigned long ret;
ret = get_prev_map_irq(intspec[1]);
if (!IS_ERR_VALUE(ret))
goto found;
ret = allocate_free_irq(intspec[1]);
if (IS_ERR_VALUE(ret))
return ret;
found:
*out_hwirq = ret + GIC_IRQ_START;
return 0;
}
const struct irq_domain_ops routable_irq_domain_ops = {
.map = crossbar_domain_map,
.unmap = crossbar_domain_unmap,
.xlate = crossbar_domain_xlate
};
static int __init crossbar_of_init(struct device_node *node)
{
int i, size, max, reserved = 0, entry;
const __be32 *irqsr;
cb = kzalloc(sizeof(*cb), GFP_KERNEL);
if (!cb)
return -ENOMEM;
cb->crossbar_base = of_iomap(node, 0);
if (!cb->crossbar_base)
goto err1;
of_property_read_u32(node, "ti,max-irqs", &max);
cb->irq_map = kzalloc(max * sizeof(int), GFP_KERNEL);
if (!cb->irq_map)
goto err2;
cb->int_max = max;
for (i = 0; i < max; i++)
cb->irq_map[i] = IRQ_FREE;
/* Get and mark reserved irqs */
irqsr = of_get_property(node, "ti,irqs-reserved", &size);
if (irqsr) {
size /= sizeof(__be32);
for (i = 0; i < size; i++) {
of_property_read_u32_index(node,
"ti,irqs-reserved",
i, &entry);
if (entry > max) {
pr_err("Invalid reserved entry\n");
goto err3;
}
cb->irq_map[entry] = IRQ_RESERVED;
}
}
/* Skip irqs hardwired to bypass the crossbar */
irqsr = of_get_property(node, "ti,irqs-skip", &size);
if (irqsr) {
size /= sizeof(__be32);
for (i = 0; i < size; i++) {
of_property_read_u32_index(node,
"ti,irqs-skip",
i, &entry);
if (entry > max) {
pr_err("Invalid skip entry\n");
ret = -EINVAL;
goto err3;
}
cb->irq_map[entry] = IRQ_SKIP;
}
}
cb->register_offsets = kzalloc(max * sizeof(int), GFP_KERNEL);
if (!cb->register_offsets)
goto err3;
of_property_read_u32(node, "ti,reg-size", &size);
switch (size) {
case 1:
cb->write = crossbar_writeb;
break;
case 2:
cb->write = crossbar_writew;
break;
case 4:
cb->write = crossbar_writel;
break;
default:
pr_err("Invalid reg-size property\n");
goto err4;
break;
}
/*
* Register offsets are not linear because of the
* reserved irqs. so find and store the offsets once.
*/
for (i = 0; i < max; i++) {
if (cb->irq_map[i] == IRQ_RESERVED)
continue;
cb->register_offsets[i] = reserved;
reserved += size;
}
of_property_read_u32(node, "ti,irqs-safe-map", &cb->safe_map);
/* Initialize the crossbar with safe map to start with */
for (i = 0; i < max; i++) {
if (cb->irq_map[i] == IRQ_RESERVED ||
cb->irq_map[i] == IRQ_SKIP)
continue;
cb->write(i, cb->safe_map);
}
register_routable_domain_ops(&routable_irq_domain_ops);
return 0;
err4:
kfree(cb->register_offsets);
err3:
kfree(cb->irq_map);
err2:
iounmap(cb->crossbar_base);
err1:
kfree(cb);
return -ENOMEM;
}
static const struct of_device_id crossbar_match[] __initconst = {
{ .compatible = "ti,irq-crossbar" },
{}
};
int __init irqcrossbar_init(void)
{
struct device_node *np;
np = of_find_matching_node(NULL, crossbar_match);
if (!np)
return -ENODEV;
crossbar_of_init(np);
return 0;
}