[PATCH v5 06/27] irq_domain/powerpc: eliminate irq_map; use irq_alloc_desc() instead

Grant Likely
2012-02-16T09:10:58Z

This patch drops the powerpc-specific irq_map table and replaces it with
directly using the irq_alloc_desc()/irq_free_desc() interfaces for allocating
and freeing irq_desc structures.

This patch is a preparation step for generalizing the powerpc-specific virq
infrastructure to become irq_domains.

As part of this change, the irq_big_lock is changed to a mutex from a raw
spinlock. There is no longer any need to use a spin lock since the irq_desc
allocation code is now responsible for the critical section of finding
an unused range of irq numbers.

The radix lookup table is also changed to store the irq_data pointer instead
of the irq_map entry since the irq_map is removed. This should end up being
functionally equivalent since only allocated irq_descs are ever added to the
radix tree.

v5: - Really don't ever allocate virq 0. The previous version could still
do it if hint == 0
- Respect irq_virq_count setting for NOMAP. Some NOMAP domains cannot
use virq values above irq_virq_count.
- Use numa_node_id() when allocating irq_descs. Ideally the API should
obtain that value from the caller, but that touches a lot of call sites
so will be deferred to a follow-on patch.
- Fix irq_find_mapping() to include irq numbers lower than
NUM_ISA_INTERRUPTS. With the switch to irq_alloc_desc*(), the lowest
possible allocated irq is now returned by arch_probe_nr_irqs().
v4: - Fix incorrect access to irq_data structure in debugfs code
- Don't ever allocate virq 0

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Milton Miller <miltonm@bga.com>
Tested-by: Olof Johansson <olof@lixom.net>
---
arch/powerpc/include/asm/irq.h | 27 -----
arch/powerpc/kernel/irq.c | 240 ++++++++++++----------------------------
2 files changed, 69 insertions(+), 198 deletions(-)

diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index cb06b39..abdd7ef 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -191,33 +191,6 @@ extern unsigned int irq_linear_revmap(struct irq_domain *host,
irq_hw_number_t hwirq);

-
-/**
- * irq_alloc_virt - Allocate virtual irq numbers
- * @host: host owning these new virtual irqs
- * @count: number of consecutive numbers to allocate
- * @hint: pass a hint number, the allocator will try to use a 1:1 mapping
- *
- * This is a low level function that is used internally by irq_create_mapping()
- * and that can be used by some irq controllers implementations for things
- * like allocating ranges of numbers for MSIs. The revmaps are left untouched.
- */
-extern unsigned int irq_alloc_virt(struct irq_domain *host,
- unsigned int count,
- unsigned int hint);
-
-/**
- * irq_free_virt - Free virtual irq numbers
- * @virq: virtual irq number of the first interrupt to free
- * @count: number of interrupts to free
- *
- * This function is the opposite of irq_alloc_virt. It will not clear reverse
- * maps, this should be done previously by unmap'ing the interrupt. In fact,
- * all interrupts covered by the range being freed should have been unmapped
- * prior to calling this.
- */
-extern void irq_free_virt(unsigned int virq, unsigned int count);
-
/**
* irq_early_init - Init irq remapping subsystem
*/
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 7305f2f..03c95f0 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -491,38 +491,29 @@ void do_softirq(void)
* IRQ controller and virtual interrupts
*/

-/* The main irq map itself is an array of NR_IRQ entries containing the
- * associate host and irq number. An entry with a host of NULL is free.
- * An entry can be allocated if it's free, the allocator always then sets
- * hwirq first to the host's invalid irq number and then fills ops.
- */
-struct irq_map_entry {
- irq_hw_number_t hwirq;
- struct irq_domain *host;
-};
-
static LIST_HEAD(irq_domain_list);
-static DEFINE_RAW_SPINLOCK(irq_big_lock);
+static DEFINE_MUTEX(irq_domain_mutex);
static DEFINE_MUTEX(revmap_trees_mutex);
-static struct irq_map_entry irq_map[NR_IRQS];
static unsigned int irq_virq_count = NR_IRQS;
static struct irq_domain *irq_default_host;

irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
{
- return irq_map[d->irq].hwirq;
+ return d->hwirq;
}
EXPORT_SYMBOL_GPL(irqd_to_hwirq);

irq_hw_number_t virq_to_hw(unsigned int virq)
{
- return irq_map[virq].hwirq;
+ struct irq_data *irq_data = irq_get_irq_data(virq);
+ return WARN_ON(!irq_data) ? 0 : irq_data->hwirq;
}
EXPORT_SYMBOL_GPL(virq_to_hw);

bool virq_is_host(unsigned int virq, struct irq_domain *host)
{
- return irq_map[virq].host == host;
+ struct irq_data *irq_data = irq_get_irq_data(virq);
+ return irq_data ? irq_data->domain == host : false;
}
EXPORT_SYMBOL_GPL(virq_is_host);

@@ -537,11 +528,10 @@ struct irq_domain *irq_alloc_host(struct device_node *of_node,
struct irq_domain_ops *ops,
irq_hw_number_t inval_irq)
{
- struct irq_domain *host;
+ struct irq_domain *host, *h;
unsigned int size = sizeof(struct irq_domain);
unsigned int i;
unsigned int *rmap;
- unsigned long flags;

/* Allocate structure and revmap table if using linear mapping */
if (revmap_type == IRQ_DOMAIN_MAP_LINEAR)
@@ -559,23 +549,20 @@ struct irq_domain *irq_alloc_host(struct device_node *of_node,
if (host->ops->match == NULL)
host->ops->match = default_irq_host_match;

- raw_spin_lock_irqsave(&irq_big_lock, flags);
-
- /* If it's a legacy controller, check for duplicates and
- * mark it as allocated (we use irq 0 host pointer for that
- */
+ mutex_lock(&irq_domain_mutex);
+ /* Make sure only one legacy controller can be created */
if (revmap_type == IRQ_DOMAIN_MAP_LEGACY) {
- if (irq_map[0].host != NULL) {
- raw_spin_unlock_irqrestore(&irq_big_lock, flags);
- of_node_put(host->of_node);
- kfree(host);
- return NULL;
+ list_for_each_entry(h, &irq_domain_list, link) {
+ if (WARN_ON(h->revmap_type == IRQ_DOMAIN_MAP_LEGACY)) {
+ mutex_unlock(&irq_domain_mutex);
+ of_node_put(host->of_node);
+ kfree(host);
+ return NULL;
+ }
}
- irq_map[0].host = host;
}
-
list_add(&host->link, &irq_domain_list);
- raw_spin_unlock_irqrestore(&irq_big_lock, flags);
+ mutex_unlock(&irq_domain_mutex);

/* Additional setups per revmap type */
switch(revmap_type) {
@@ -584,10 +571,9 @@ struct irq_domain *irq_alloc_host(struct device_node *of_node,
host->inval_irq = 0;
/* setup us as the host for all legacy interrupts */
for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
- irq_map[i].hwirq = i;
- smp_wmb();
- irq_map[i].host = host;
- smp_wmb();
+ struct irq_data *irq_data = irq_get_irq_data(i);
+ irq_data->hwirq = i;
+ irq_data->domain = host;

/* Legacy flags are left to default at this point,
* one can then use irq_create_mapping() to
@@ -604,7 +590,6 @@ struct irq_domain *irq_alloc_host(struct device_node *of_node,
for (i = 0; i < revmap_arg; i++)
rmap[i] = NO_IRQ;
host->revmap_data.linear.size = revmap_arg;
- smp_wmb();
host->revmap_data.linear.revmap = rmap;
break;
case IRQ_DOMAIN_MAP_TREE:
@@ -622,20 +607,19 @@ struct irq_domain *irq_alloc_host(struct device_node *of_node,
struct irq_domain *irq_find_host(struct device_node *node)
{
struct irq_domain *h, *found = NULL;
- unsigned long flags;

/* We might want to match the legacy controller last since
* it might potentially be set to match all interrupts in
* the absence of a device node. This isn't a problem so far
* yet though...
*/
- raw_spin_lock_irqsave(&irq_big_lock, flags);
+ mutex_lock(&irq_domain_mutex);
list_for_each_entry(h, &irq_domain_list, link)
if (h->ops->match(h, node)) {
found = h;
break;
}
- raw_spin_unlock_irqrestore(&irq_big_lock, flags);
+ mutex_unlock(&irq_domain_mutex);
return found;
}
EXPORT_SYMBOL_GPL(irq_find_host);
@@ -659,33 +643,20 @@ void irq_set_virq_count(unsigned int count)
static int irq_setup_virq(struct irq_domain *host, unsigned int virq,
irq_hw_number_t hwirq)
{
- int res;
-
- res = irq_alloc_desc_at(virq, 0);
- if (res != virq) {
- pr_debug("irq: -> allocating desc failed\n");
- goto error;
- }
-
- /* map it */
- smp_wmb();
- irq_map[virq].hwirq = hwirq;
- smp_mb();
+ struct irq_data *irq_data = irq_get_irq_data(virq);

+ irq_data->hwirq = hwirq;
+ irq_data->domain = host;
if (host->ops->map(host, virq, hwirq)) {
pr_debug("irq: -> mapping failed, freeing\n");
- goto errdesc;
+ irq_data->domain = NULL;
+ irq_data->hwirq = 0;
+ return -1;
}

irq_clear_status_flags(virq, IRQ_NOREQUEST);

return 0;
-
-errdesc:
- irq_free_descs(virq, 1);
-error:
- irq_free_virt(virq, 1);
- return -1;
}

unsigned int irq_create_direct_mapping(struct irq_domain *host)
@@ -698,16 +669,24 @@ unsigned int irq_create_direct_mapping(struct irq_domain *host)
BUG_ON(host == NULL);
WARN_ON(host->revmap_type != IRQ_DOMAIN_MAP_NOMAP);

- virq = irq_alloc_virt(host, 1, 0);
+ virq = irq_alloc_desc_from(1, 0);
if (virq == NO_IRQ) {
pr_debug("irq: create_direct virq allocation failed\n");
return NO_IRQ;
}
+ if (virq >= irq_virq_count) {
+ pr_err("ERROR: no free irqs available below %i maximum\n",
+ irq_virq_count);
+ irq_free_desc(virq);
+ return 0;
+ }

pr_debug("irq: create_direct obtained virq %d\n", virq);

- if (irq_setup_virq(host, virq, virq))
+ if (irq_setup_virq(host, virq, virq)) {
+ irq_free_desc(virq);
return NO_IRQ;
+ }

return virq;
}
@@ -747,15 +726,22 @@ unsigned int irq_create_mapping(struct irq_domain *host,
} else {
/* Allocate a virtual interrupt number */
hint = hwirq % irq_virq_count;
- virq = irq_alloc_virt(host, 1, hint);
+ if (hint == 0)
+ hint = 1;
+ virq = irq_alloc_desc_from(hint, 0);
+ if (!virq)
+ virq = irq_alloc_desc_from(1, 0);
if (virq == NO_IRQ) {
pr_debug("irq: -> virq allocation failed\n");
return NO_IRQ;
}
}

- if (irq_setup_virq(host, virq, hwirq))
+ if (irq_setup_virq(host, virq, hwirq)) {
+ if (host->revmap_type != IRQ_DOMAIN_MAP_LEGACY)
+ irq_free_desc(virq);
return NO_IRQ;
+ }

pr_debug("irq: irq %lu on host %s mapped to virtual irq %u\n",
hwirq, host->of_node ? host->of_node->full_name : "null", virq);
@@ -806,13 +792,14 @@ EXPORT_SYMBOL_GPL(irq_create_of_mapping);

void irq_dispose_mapping(unsigned int virq)
{
+ struct irq_data *irq_data = irq_get_irq_data(virq);
struct irq_domain *host;
irq_hw_number_t hwirq;

- if (virq == NO_IRQ)
+ if (virq == NO_IRQ || !irq_data)
return;

- host = irq_map[virq].host;
+ host = irq_data->domain;
if (WARN_ON(host == NULL))
return;

@@ -834,7 +821,7 @@ void irq_dispose_mapping(unsigned int virq)
smp_mb();

/* Clear reverse map */
- hwirq = irq_map[virq].hwirq;
+ hwirq = irq_data->hwirq;
switch(host->revmap_type) {
case IRQ_DOMAIN_MAP_LINEAR:
if (hwirq < host->revmap_data.linear.size)
@@ -848,12 +835,9 @@ void irq_dispose_mapping(unsigned int virq)
}

/* Destroy map */
- smp_mb();
- irq_map[virq].hwirq = host->inval_irq;
+ irq_data->hwirq = host->inval_irq;

- irq_free_descs(virq, 1);
- /* Free it */
- irq_free_virt(virq, 1);
+ irq_free_desc(virq);
}
EXPORT_SYMBOL_GPL(irq_dispose_mapping);

@@ -874,16 +858,16 @@ unsigned int irq_find_mapping(struct irq_domain *host,
return hwirq;

/* Slow path does a linear search of the map */
- if (hint < NUM_ISA_INTERRUPTS)
- hint = NUM_ISA_INTERRUPTS;
+ if (hint == 0)
+ hint = 1;
i = hint;
- do {
- if (irq_map[i].host == host &&
- irq_map[i].hwirq == hwirq)
+ do {
+ struct irq_data *data = irq_get_irq_data(i);
+ if (data && (data->domain == host) && (data->hwirq == hwirq))
return i;
i++;
if (i >= irq_virq_count)
- i = NUM_ISA_INTERRUPTS;
+ i = 1;
} while(i != hint);
return NO_IRQ;
}
@@ -928,19 +912,17 @@ int irq_choose_cpu(const struct cpumask *mask)
unsigned int irq_radix_revmap_lookup(struct irq_domain *host,
irq_hw_number_t hwirq)
{
- struct irq_map_entry *ptr;
- unsigned int virq;
+ struct irq_data *irq_data;

if (WARN_ON_ONCE(host->revmap_type != IRQ_DOMAIN_MAP_TREE))
return irq_find_mapping(host, hwirq);

/*
- * The ptr returned references the static global irq_map.
- * but freeing an irq can delete nodes along the path to
+ * Freeing an irq can delete nodes along the path to
* do the lookup via call_rcu.
*/
rcu_read_lock();
- ptr = radix_tree_lookup(&host->revmap_data.tree, hwirq);
+ irq_data = radix_tree_lookup(&host->revmap_data.tree, hwirq);
rcu_read_unlock();

/*
@@ -948,24 +930,20 @@ unsigned int irq_radix_revmap_lookup(struct irq_domain *host,
* Else fallback to linear lookup - this should not happen in practice
* as it means that we failed to insert the node in the radix tree.
*/
- if (ptr)
- virq = ptr - irq_map;
- else
- virq = irq_find_mapping(host, hwirq);
-
- return virq;
+ return irq_data ? irq_data->irq : irq_find_mapping(host, hwirq);
}

void irq_radix_revmap_insert(struct irq_domain *host, unsigned int virq,
irq_hw_number_t hwirq)
{
+ struct irq_data *irq_data = irq_get_irq_data(virq);
+
if (WARN_ON(host->revmap_type != IRQ_DOMAIN_MAP_TREE))
return;

if (virq != NO_IRQ) {
mutex_lock(&revmap_trees_mutex);
- radix_tree_insert(&host->revmap_data.tree, hwirq,
- &irq_map[virq]);
+ radix_tree_insert(&host->revmap_data.tree, hwirq, irq_data);
mutex_unlock(&revmap_trees_mutex);
}
}
@@ -994,86 +972,6 @@ unsigned int irq_linear_revmap(struct irq_domain *host,
return revmap[hwirq];
}

-unsigned int irq_alloc_virt(struct irq_domain *host,
- unsigned int count,
- unsigned int hint)
-{
- unsigned long flags;
- unsigned int i, j, found = NO_IRQ;
-
- if (count == 0 || count > (irq_virq_count - NUM_ISA_INTERRUPTS))
- return NO_IRQ;
-
- raw_spin_lock_irqsave(&irq_big_lock, flags);
-
- /* Use hint for 1 interrupt if any */
- if (count == 1 && hint >= NUM_ISA_INTERRUPTS &&
- hint < irq_virq_count && irq_map[hint].host == NULL) {
- found = hint;
- goto hint_found;
- }
-
- /* Look for count consecutive numbers in the allocatable
- * (non-legacy) space
- */
- for (i = NUM_ISA_INTERRUPTS, j = 0; i < irq_virq_count; i++) {
- if (irq_map[i].host != NULL)
- j = 0;
- else
- j++;
-
- if (j == count) {
- found = i - count + 1;
- break;
- }
- }
- if (found == NO_IRQ) {
- raw_spin_unlock_irqrestore(&irq_big_lock, flags);
- return NO_IRQ;
- }
- hint_found:
- for (i = found; i < (found + count); i++) {
- irq_map[i].hwirq = host->inval_irq;
- smp_wmb();
- irq_map[i].host = host;
- }
- raw_spin_unlock_irqrestore(&irq_big_lock, flags);
- return found;
-}
-
-void irq_free_virt(unsigned int virq, unsigned int count)
-{
- unsigned long flags;
- unsigned int i;
-
- WARN_ON (virq < NUM_ISA_INTERRUPTS);
- WARN_ON (count == 0 || (virq + count) > irq_virq_count);
-
- if (virq < NUM_ISA_INTERRUPTS) {
- if (virq + count < NUM_ISA_INTERRUPTS)
- return;
- count =- NUM_ISA_INTERRUPTS - virq;
- virq = NUM_ISA_INTERRUPTS;
- }
-
- if (count > irq_virq_count || virq > irq_virq_count - count) {
- if (virq > irq_virq_count)
- return;
- count = irq_virq_count - virq;
- }
-
- raw_spin_lock_irqsave(&irq_big_lock, flags);
- for (i = virq; i < (virq + count); i++) {
- struct irq_domain *host;
-
- host = irq_map[i].host;
- irq_map[i].hwirq = host->inval_irq;
- smp_wmb();
- irq_map[i].host = NULL;
- }
- raw_spin_unlock_irqrestore(&irq_big_lock, flags);
-}
-
int arch_early_irq_init(void)
{
return 0;
@@ -1103,7 +1001,7 @@ static int virq_debug_show(struct seq_file *m, void *private)
struct irq_chip *chip;

seq_printf(m, "%5d ", i);
- seq_printf(m, "0x%05lx ", irq_map[i].hwirq);
+ seq_printf(m, "0x%05lx ", desc->irq_data.hwirq);

chip = irq_desc_get_chip(desc);
if (chip && chip->name)
@@ -1115,8 +1013,8 @@ static int virq_debug_show(struct seq_file *m, void *private)
data = irq_desc_get_chip_data(desc);
seq_printf(m, "0x%16p ", data);

- if (irq_map[i].host && irq_map[i].host->of_node)
- p = irq_map[i].host->of_node->full_name;
+ if (desc->irq_data.domain->of_node)
+ p = desc->irq_data.domain->of_node->full_name;
else
p = none;
seq_printf(m, "%s\n", p);
--
1.7.9