Re: [PATCH 2/3] irq: Add hw continuous IRQs map to virtual continuousIRQs support
From: Mike Qiu
Date: Tue Mar 05 2013 - 02:20:33 EST
ä 2013/3/5 10:23, Michael Ellerman åé:
On Tue, Jan 15, 2013 at 03:38:55PM +0800, Mike Qiu wrote:
Adding a function irq_create_mapping_many() which can associate
multiple MSIs to a continous irq mapping.
This is needed to enable multiple MSI support for pSeries.
Signed-off-by: Mike Qiu <qiudayu@xxxxxxxxxxxxxxxxxx>
---
include/linux/irq.h | 2 +
include/linux/irqdomain.h | 3 ++
kernel/irq/irqdomain.c | 61 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 66 insertions(+), 0 deletions(-)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 60ef45b..e00a7ec 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -592,6 +592,8 @@ int __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
#define irq_alloc_desc_from(from, node) \
irq_alloc_descs(-1, from, 1, node)
+#define irq_alloc_desc_n(nevc, node) \
+ irq_alloc_descs(-1, 0, nevc, node)
This has been superseeded by irq_alloc_descs_from(), which is the right
way to do it.
Yes, but irq_alloc_descs_from() just for 1 irq, and if I change the api,
maybe a lot places which call this
function will be affact.
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 0d5b17b..831dded 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -168,6 +168,9 @@ extern int irq_create_strict_mappings(struct irq_domain *domain,
unsigned int irq_base,
irq_hw_number_t hwirq_base, int count);
+extern int irq_create_mapping_many(struct irq_domain *domain,
+ irq_hw_number_t hwirq_base, int count);
+
static inline int irq_create_identity_mapping(struct irq_domain *host,
irq_hw_number_t hwirq)
{
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 96f3a1d..38648e6 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -636,6 +636,67 @@ int irq_create_strict_mappings(struct irq_domain *domain, unsigned int irq_base,
}
EXPORT_SYMBOL_GPL(irq_create_strict_mappings);
+/**
+ * irq_create_mapping_many - Map a range of hw IRQs to a range of virtual IRQs
+ * @domain: domain owning the interrupt range
+ * @hwirq_base: beginning of continuous hardware IRQ range
+ * @count: Number of interrupts to map
For multiple-MSI the allocated interrupt numbers must be a power-of-2,
and must be naturally aligned. I don't /think/ that's a requirement for
the virtual numbers, but it's probably best that we do it anyway.
So this API needs to specify that it will give you back a power-of-2
block that is naturally aligned - otherwise you can't use it for MSI.
rtas_call will return the numbers of hardware interrupt, and it should
be power-of-2,
as this I think do not need to specify
+ * This routine is used for allocating and mapping a range of hardware
+ * irqs to virtual IRQs where the virtual irq numbers are not at pre-defined
+ * locations.
This comment doesn't make sense to me.
+ *
+ * Greater than 0 is returned upon success, while any failure to establish a
+ * static mapping is treated as an error.
+ */
+int irq_create_mapping_many(struct irq_domain *domain,
+ irq_hw_number_t hwirq_base, int count)
+{
+ int ret, irq_base;
+ int virq, i;
+
+ pr_debug("irq_create_mapping(0x%p, 0x%lx)\n", domain, hwirq_base);
I'd like to see this whole function rewritten to reduce the duplication
vs irq_create_mapping(). I don't see any reason why this can't be the
core routine, and irq_create_mapping() becomes a caller of it, passing a
count of 1 ?
It's good suggestion.
+ /* Look for default domain if nececssary */
+ if (!domain)
+ domain = irq_default_domain;
+ if (!domain) {
+ pr_warn("irq_create_mapping called for NULL domain, hwirq=%lx\n"
+ , hwirq_base);
+ WARN_ON(1);
+ return 0;
+ }
+ pr_debug("-> using domain @%p\n", domain);
+
+ /* For IRQ_DOMAIN_MAP_LEGACY, get the first virtual interrupt number */
+ if (domain->revmap_type == IRQ_DOMAIN_MAP_LEGACY)
+ return irq_domain_legacy_revmap(domain, hwirq_base);
The above doesn't work.
Why it doesn't work ?
+ /* Check if mapping already exists */
+ for (i = 0; i < count; i++) {
+ virq = irq_find_mapping(domain, hwirq_base+i);
+ if (virq) {
+ pr_debug("existing mapping on virq %d,"
+ " now dispose it first\n", virq);
+ irq_dispose_mapping(virq);
You might have just disposed of someone elses mapping, we shouldn't do
that. It should be an error to the caller.
It's a good question. If the interrupt used for someone elses, why I can
apply it from the system?
So it may someone else forget to dispose mapping, and it never be used
for others as I have got
the interrupt I think.
cheers
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