diff options
author | Marc Zyngier <marc.zyngier@arm.com> | 2016-04-11 11:57:53 +0300 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2016-05-02 14:42:51 +0300 |
commit | 9e2c986cb460bf97154f18e85aa833739a1e8dc7 (patch) | |
tree | e99c9e595296ef212031e1ef1498458aee8711a3 /include/linux/irqchip | |
parent | 222df54fd8b7641dcc81476f157806bb3144ee1d (diff) |
irqchip: Add per-cpu interrupt partitioning library
We've unfortunately started seeing a situation where percpu interrupts
are partitioned in the system: one arbitrary set of CPUs has an
interrupt connected to a type of device, while another disjoint
set of CPUs has the same interrupt connected to another type of device.
This makes it impossible to have a device driver requesting this interrupt
using the current percpu-interrupt abstraction, as the same interrupt number
is now potentially claimed by at least two drivers, and we forbid interrupt
sharing on per-cpu interrupt.
A solution to this is to turn things upside down. Let's assume that our
system describes all the possible partitions for a given interrupt, and
give each of them a unique identifier. It is then possible to create
a namespace where the affinity identifier itself is a form of interrupt
number. At this point, it becomes easy to implement a set of partitions
as a cascaded irqchip, each affinity identifier being the HW irq.
This allows us to keep a number of nice properties:
- Each partition results in a separate percpu-interrupt (with a restrictied
affinity), which keeps drivers happy.
- Because the underlying interrupt is still per-cpu, the overhead of
the indirection can be kept pretty minimal.
- The core code can ignore most of that crap.
For that purpose, we implement a small library that deals with some of
the boilerplate code, relying on platform-specific drivers to provide
a description of the affinity sets and a set of callbacks.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Link: http://lkml.kernel.org/r/1460365075-7316-4-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/irqchip')
-rw-r--r-- | include/linux/irqchip/irq-partition-percpu.h | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/include/linux/irqchip/irq-partition-percpu.h b/include/linux/irqchip/irq-partition-percpu.h new file mode 100644 index 000000000000..87433a5d1285 --- /dev/null +++ b/include/linux/irqchip/irq-partition-percpu.h @@ -0,0 +1,59 @@ +/* + * Copyright (C) 2016 ARM Limited, All Rights Reserved. + * Author: Marc Zyngier <marc.zyngier@arm.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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/fwnode.h> +#include <linux/cpumask.h> +#include <linux/irqdomain.h> + +struct partition_affinity { + cpumask_t mask; + void *partition_id; +}; + +struct partition_desc; + +#ifdef CONFIG_PARTITION_PERCPU +int partition_translate_id(struct partition_desc *desc, void *partition_id); +struct partition_desc *partition_create_desc(struct fwnode_handle *fwnode, + struct partition_affinity *parts, + int nr_parts, + int chained_irq, + const struct irq_domain_ops *ops); +struct irq_domain *partition_get_domain(struct partition_desc *dsc); +#else +static inline int partition_translate_id(struct partition_desc *desc, + void *partition_id) +{ + return -EINVAL; +} + +static inline +struct partition_desc *partition_create_desc(struct fwnode_handle *fwnode, + struct partition_affinity *parts, + int nr_parts, + int chained_irq, + const struct irq_domain_ops *ops) +{ + return NULL; +} + +static inline +struct irq_domain *partition_get_domain(struct partition_desc *dsc) +{ + return NULL; +} +#endif |