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drivers/base: Add MSI domain support for non-PCI devices

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With the msi_list and the msi_domain properties now being at the
generic device level, it is starting to be relatively easy to offer
a generic way of providing non-PCI MSIs.

The two major hurdles with this idea are:

- Lack of global ID that identifies a device: this is worked around by
  having a global ID allocator for each device that gets enrolled in
  the platform MSI subsystem

- Lack of standard way to write the message in the generating device.
  This is solved by mandating driver code to provide a write_msg
  callback, so that everyone can have their own square wheel

Apart from that, the API is fairly straightforward:

- platform_msi_create_irq_domain creates an MSI domain that gets
  tagged with DOMAIN_BUS_PLATFORM_MSI

- platform_msi_domain_alloc_irqs allocate MSIs for a given device,
  populating the msi_list

- platform_msi_domain_free_irqs does what is written on the tin

[ tglx: Created a seperate struct platform_msi_desc and added
  	kerneldoc entries ]

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Ma Jun <majun258@huawei.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Duc Dang <dhdang@apm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1438091186-10244-10-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Marc Zyngier 2015-07-28 14:46:16 +01:00 committed by Thomas Gleixner
parent c706c239af
commit c09fcc4b2b
3 changed files with 305 additions and 0 deletions
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1
drivers/base/Makefile
View File

@ -22,6 +22,7 @@ obj-$(CONFIG_REGMAP) += regmap/
obj-$(CONFIG_SOC_BUS) += soc.o
obj-$(CONFIG_PINCTRL) += pinctrl.o
obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o
ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG

282
drivers/base/platform-msi.c Normal file
View File

@ -0,0 +1,282 @@
/*
* MSI framework for platform devices
*
* Copyright (C) 2015 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/device.h>
#include <linux/idr.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/msi.h>
#include <linux/slab.h>
#define DEV_ID_SHIFT 24
/*
* Internal data structure containing a (made up, but unique) devid
* and the callback to write the MSI message.
*/
struct platform_msi_priv_data {
irq_write_msi_msg_t write_msg;
int devid;
};
/* The devid allocator */
static DEFINE_IDA(platform_msi_devid_ida);
#ifdef GENERIC_MSI_DOMAIN_OPS
/*
* Convert an msi_desc to a globaly unique identifier (per-device
* devid + msi_desc position in the msi_list).
*/
static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
{
u32 devid;
devid = desc->platform.msi_priv_data->devid;
return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
}
static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
{
arg->desc = desc;
arg->hwirq = platform_msi_calc_hwirq(desc);
}
static int platform_msi_init(struct irq_domain *domain,
struct msi_domain_info *info,
unsigned int virq, irq_hw_number_t hwirq,
msi_alloc_info_t *arg)
{
struct irq_data *data;
irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
info->chip, info->chip_data);
/*
* Save the MSI descriptor in handler_data so that the
* irq_write_msi_msg callback can retrieve it (and the
* associated device).
*/
data = irq_domain_get_irq_data(domain, virq);
data->handler_data = arg->desc;
return 0;
}
#else
#define platform_msi_set_desc NULL
#define platform_msi_init NULL
#endif
static void platform_msi_update_dom_ops(struct msi_domain_info *info)
{
struct msi_domain_ops *ops = info->ops;
BUG_ON(!ops);
if (ops->msi_init == NULL)
ops->msi_init = platform_msi_init;
if (ops->set_desc == NULL)
ops->set_desc = platform_msi_set_desc;
}
static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
{
struct msi_desc *desc = irq_data_get_irq_handler_data(data);
struct platform_msi_priv_data *priv_data;
priv_data = desc->platform.msi_priv_data;
priv_data->write_msg(desc, msg);
}
static void platform_msi_update_chip_ops(struct msi_domain_info *info)
{
struct irq_chip *chip = info->chip;
BUG_ON(!chip);
if (!chip->irq_mask)
chip->irq_mask = irq_chip_mask_parent;
if (!chip->irq_unmask)
chip->irq_unmask = irq_chip_unmask_parent;
if (!chip->irq_eoi)
chip->irq_eoi = irq_chip_eoi_parent;
if (!chip->irq_set_affinity)
chip->irq_set_affinity = msi_domain_set_affinity;
if (!chip->irq_write_msi_msg)
chip->irq_write_msi_msg = platform_msi_write_msg;
}
static void platform_msi_free_descs(struct device *dev)
{
struct msi_desc *desc, *tmp;
list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
list_del(&desc->list);
free_msi_entry(desc);
}
}
static int platform_msi_alloc_descs(struct device *dev, int nvec,
struct platform_msi_priv_data *data)
{
int i;
for (i = 0; i < nvec; i++) {
struct msi_desc *desc;
desc = alloc_msi_entry(dev);
if (!desc)
break;
desc->platform.msi_priv_data = data;
desc->platform.msi_index = i;
desc->nvec_used = 1;
list_add_tail(&desc->list, dev_to_msi_list(dev));
}
if (i != nvec) {
/* Clean up the mess */
platform_msi_free_descs(dev);
return -ENOMEM;
}
return 0;
}
/**
* platform_msi_create_irq_domain - Create a platform MSI interrupt domain
* @np: Optional device-tree node of the interrupt controller
* @info: MSI domain info
* @parent: Parent irq domain
*
* Updates the domain and chip ops and creates a platform MSI
* interrupt domain.
*
* Returns:
* A domain pointer or NULL in case of failure.
*/
struct irq_domain *platform_msi_create_irq_domain(struct device_node *np,
struct msi_domain_info *info,
struct irq_domain *parent)
{
struct irq_domain *domain;
if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
platform_msi_update_dom_ops(info);
if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
platform_msi_update_chip_ops(info);
domain = msi_create_irq_domain(np, info, parent);
if (domain)
domain->bus_token = DOMAIN_BUS_PLATFORM_MSI;
return domain;
}
/**
* platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
* @dev: The device for which to allocate interrupts
* @nvec: The number of interrupts to allocate
* @write_msi_msg: Callback to write an interrupt message for @dev
*
* Returns:
* Zero for success, or an error code in case of failure
*/
int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
irq_write_msi_msg_t write_msi_msg)
{
struct platform_msi_priv_data *priv_data;
int err;
/*
* Limit the number of interrupts to 256 per device. Should we
* need to bump this up, DEV_ID_SHIFT should be adjusted
* accordingly (which would impact the max number of MSI
* capable devices).
*/
if (!dev->msi_domain || !write_msi_msg || !nvec ||
nvec > (1 << (32 - DEV_ID_SHIFT)))
return -EINVAL;
if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
dev_err(dev, "Incompatible msi_domain, giving up\n");
return -EINVAL;
}
/* Already had a helping of MSI? Greed... */
if (!list_empty(dev_to_msi_list(dev)))
return -EBUSY;
priv_data = kzalloc(sizeof(*priv_data), GFP_KERNEL);
if (!priv_data)
return -ENOMEM;
priv_data->devid = ida_simple_get(&platform_msi_devid_ida,
0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
if (priv_data->devid < 0) {
err = priv_data->devid;
goto out_free_data;
}
priv_data->write_msg = write_msi_msg;
err = platform_msi_alloc_descs(dev, nvec, priv_data);
if (err)
goto out_free_id;
err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
if (err)
goto out_free_desc;
return 0;
out_free_desc:
platform_msi_free_descs(dev);
out_free_id:
ida_simple_remove(&platform_msi_devid_ida, priv_data->devid);
out_free_data:
kfree(priv_data);
return err;
}
/**
* platform_msi_domain_free_irqs - Free MSI interrupts for @dev
* @dev: The device for which to free interrupts
*/
void platform_msi_domain_free_irqs(struct device *dev)
{
struct msi_desc *desc;
desc = first_msi_entry(dev);
if (desc) {
struct platform_msi_priv_data *data;
data = desc->platform.msi_priv_data;
ida_simple_remove(&platform_msi_devid_ida, data->devid);
kfree(data);
}
msi_domain_free_irqs(dev->msi_domain, dev);
platform_msi_free_descs(dev);
}

22
include/linux/msi.h
View File

@ -15,9 +15,23 @@ extern int pci_msi_ignore_mask;
struct irq_data;
struct msi_desc;
struct pci_dev;
struct platform_msi_priv_data;
void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg);
typedef void (*irq_write_msi_msg_t)(struct msi_desc *desc,
struct msi_msg *msg);
/**
* platform_msi_desc - Platform device specific msi descriptor data
* @msi_priv_data: Pointer to platform private data
* @msi_index: The index of the MSI descriptor for multi MSI
*/
struct platform_msi_desc {
struct platform_msi_priv_data *msi_priv_data;
u16 msi_index;
};
/**
* struct msi_desc - Descriptor structure for MSI based interrupts
* @list: List head for management
@ -36,6 +50,7 @@ void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg);
* @default_irq:[PCI MSI/X] The default pre-assigned non-MSI irq
* @mask_pos: [PCI MSI] Mask register position
* @mask_base: [PCI MSI-X] Mask register base address
* @platform: [platform] Platform device specific msi descriptor data
*/
struct msi_desc {
/* Shared device/bus type independent data */
@ -71,6 +86,7 @@ struct msi_desc {
* anonymous for now as it would require an immediate
* tree wide cleanup.
*/
struct platform_msi_desc platform;
};
};
@ -257,6 +273,12 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev);
struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain);
struct irq_domain *platform_msi_create_irq_domain(struct device_node *np,
struct msi_domain_info *info,
struct irq_domain *parent);
int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
irq_write_msi_msg_t write_msi_msg);
void platform_msi_domain_free_irqs(struct device *dev);
#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN