[PATCH RFC 03/15] drivers/base: Allocate/free platform-msi interrupts by group

From: Dave Jiang
Date: Tue Apr 21 2020 - 19:34:14 EST

From: Megha Dey <megha.dey@xxxxxxxxxxxxxxx>

This is a preparatory patch to introduce Interrupt Message Store (IMS).

Dynamic allocation is IMS vectors is a requirement for devices which
support Scalable I/o virtualization. A driver can allocate and free
vectors not just once during probe (as was the case with the MSI/MSI-X)
but also in the post probe phase where actual demand is available.

Thus, introduce an API, platform_msi_domain_alloc_irqs_group() which
drivers using IMS would be able to call multiple times. The vectors
allocated each time this API is called are associated with a group ID,
starting from 1. To free the vectors associated with a particular group,
platform_msi_domain_free_irqs_group() API can be called.

The existing drivers using platform-msi infrastructure will continue to
use the existing alloc (platform_msi_domain_alloc_irqs) and free
(platform_msi_domain_free_irqs) APIs and are assigned a default group 0.

Signed-off-by: Megha Dey <megha.dey@xxxxxxxxxxxxxxx>
---
drivers/base/platform-msi.c | 131 ++++++++++++++++++++++++++++++++-----------
include/linux/device.h | 1
include/linux/msi.h | 47 +++++++++++----
kernel/irq/msi.c | 43 +++++++++++---
4 files changed, 169 insertions(+), 53 deletions(-)

diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
index b25c52f734dc..2696aa75983b 100644
--- a/drivers/base/platform-msi.c
+++ b/drivers/base/platform-msi.c
@@ -106,16 +106,28 @@ static void platform_msi_update_chip_ops(struct msi_domain_info *info)
info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
}

-static void platform_msi_free_descs(struct device *dev, int base, int nvec)
+static void platform_msi_free_descs(struct device *dev, int base, int nvec,
+ unsigned int group)
{
struct msi_desc *desc, *tmp;
-
- list_for_each_entry_safe(desc, tmp, dev_to_platform_msi_list(dev),
- list) {
- if (desc->platform.msi_index >= base &&
- desc->platform.msi_index < (base + nvec)) {
- list_del(&desc->list);
- free_msi_entry(desc);
+ struct platform_msi_group_entry *platform_msi_group,
+ *tmp_platform_msi_group;
+
+ list_for_each_entry_safe(platform_msi_group, tmp_platform_msi_group,
+ dev_to_platform_msi_group_list(dev),
+ group_list) {
+ if (platform_msi_group->group_id == group) {
+ list_for_each_entry_safe(desc, tmp,
+ &platform_msi_group->entry_list,
+ list) {
+ if (desc->platform.msi_index >= base &&
+ desc->platform.msi_index < (base + nvec)) {
+ list_del(&desc->list);
+ free_msi_entry(desc);
+ }
+ }
+ list_del(&platform_msi_group->group_list);
+ kfree(platform_msi_group);
}
}
}
@@ -128,8 +140,8 @@ static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq,
struct msi_desc *desc;
int i, base = 0;

- if (!list_empty(dev_to_platform_msi_list(dev))) {
- desc = list_last_entry(dev_to_platform_msi_list(dev),
+ if (!list_empty(platform_msi_current_group_entry_list(dev))) {
+ desc = list_last_entry(platform_msi_current_group_entry_list(dev),
struct msi_desc, list);
base = desc->platform.msi_index + 1;
}
@@ -143,12 +155,13 @@ static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq,
desc->platform.msi_index = base + i;
desc->irq = virq ? virq + i : 0;

- list_add_tail(&desc->list, dev_to_platform_msi_list(dev));
+ list_add_tail(&desc->list,
+ platform_msi_current_group_entry_list(dev));
}

if (i != nvec) {
/* Clean up the mess */
- platform_msi_free_descs(dev, base, nvec);
+ platform_msi_free_descs(dev, base, nvec, dev->group_id);

return -ENOMEM;
}
@@ -214,7 +227,7 @@ platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
}

/* Already had a helping of MSI? Greed... */
- if (!list_empty(dev_to_platform_msi_list(dev)))
+ if (!list_empty(platform_msi_current_group_entry_list(dev)))
return ERR_PTR(-EBUSY);

datap = kzalloc(sizeof(*datap), GFP_KERNEL);
@@ -253,11 +266,36 @@ static void platform_msi_free_priv_data(struct platform_msi_priv_data *data)
int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
const struct platform_msi_ops *platform_ops)
{
+ return platform_msi_domain_alloc_irqs_group(dev, nvec, platform_ops,
+ NULL);
+}
+EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs);
+
+int platform_msi_domain_alloc_irqs_group(struct device *dev, unsigned int nvec,
+ const struct platform_msi_ops *platform_ops,
+ unsigned int *group_id)
+{
+ struct platform_msi_group_entry *platform_msi_group;
struct platform_msi_priv_data *priv_data;
int err;

dev->platform_msi_type = GEN_PLAT_MSI;

+ if (group_id)
+ *group_id = ++dev->group_id;
+
+ platform_msi_group = kzalloc(sizeof(*platform_msi_group), GFP_KERNEL);
+ if (!platform_msi_group) {
+ err = -ENOMEM;
+ goto out_platform_msi_group;
+ }
+
+ INIT_LIST_HEAD(&platform_msi_group->group_list);
+ INIT_LIST_HEAD(&platform_msi_group->entry_list);
+ platform_msi_group->group_id = dev->group_id;
+ list_add_tail(&platform_msi_group->group_list,
+ dev_to_platform_msi_group_list(dev));
+
priv_data = platform_msi_alloc_priv_data(dev, nvec, platform_ops);
if (IS_ERR(priv_data))
return PTR_ERR(priv_data);
@@ -273,13 +311,14 @@ int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
return 0;

out_free_desc:
- platform_msi_free_descs(dev, 0, nvec);
+ platform_msi_free_descs(dev, 0, nvec, dev->group_id);
out_free_priv_data:
platform_msi_free_priv_data(priv_data);
-
+out_platform_msi_group:
+ kfree(platform_msi_group);
return err;
}
-EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs);
+EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs_group);

/**
* platform_msi_domain_free_irqs - Free MSI interrupts for @dev
@@ -287,17 +326,30 @@ EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs);
*/
void platform_msi_domain_free_irqs(struct device *dev)
{
- if (!list_empty(dev_to_platform_msi_list(dev))) {
- struct msi_desc *desc;
+ platform_msi_domain_free_irqs_group(dev, 0);
+}
+EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs);

- desc = first_platform_msi_entry(dev);
- platform_msi_free_priv_data(desc->platform.msi_priv_data);
+void platform_msi_domain_free_irqs_group(struct device *dev, unsigned int group)
+{
+ struct platform_msi_group_entry *platform_msi_group;
+
+ list_for_each_entry(platform_msi_group,
+ dev_to_platform_msi_group_list((dev)), group_list) {
+ if (platform_msi_group->group_id == group) {
+ if (!list_empty(&platform_msi_group->entry_list)) {
+ struct msi_desc *desc;
+
+ desc = list_first_entry(&(platform_msi_group)->entry_list,
+ struct msi_desc, list);
+ platform_msi_free_priv_data(desc->platform.msi_priv_data);
+ }
+ }
}
-
- msi_domain_free_irqs(dev->msi_domain, dev);
- platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);
+ msi_domain_free_irqs_group(dev->msi_domain, dev, group);
+ platform_msi_free_descs(dev, 0, MAX_DEV_MSIS, group);
}
-EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs);
+EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs_group);

/**
* platform_msi_get_host_data - Query the private data associated with
@@ -373,15 +425,28 @@ void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
{
struct platform_msi_priv_data *data = domain->host_data;
struct msi_desc *desc, *tmp;
- for_each_platform_msi_entry_safe(desc, tmp, data->dev) {
- if (WARN_ON(!desc->irq || desc->nvec_used != 1))
- return;
- if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
- continue;
-
- irq_domain_free_irqs_common(domain, desc->irq, 1);
- list_del(&desc->list);
- free_msi_entry(desc);
+ struct platform_msi_group_entry *platform_msi_group,
+ *tmp_platform_msi_group;
+
+ list_for_each_entry_safe(platform_msi_group, tmp_platform_msi_group,
+ dev_to_platform_msi_group_list(data->dev),
+ group_list) {
+ if (platform_msi_group->group_id == data->dev->group_id) {
+ list_for_each_entry_safe(desc, tmp,
+ &platform_msi_group->entry_list,
+ list) {
+ if (WARN_ON(!desc->irq || desc->nvec_used != 1))
+ return;
+ if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
+ continue;
+
+ irq_domain_free_irqs_common(domain, desc->irq, 1);
+ list_del(&desc->list);
+ free_msi_entry(desc);
+ }
+ list_del(&platform_msi_group->group_list);
+ kfree(platform_msi_group);
+ }
}
}

diff --git a/include/linux/device.h b/include/linux/device.h
index cbcecb14584e..f6700b85eb95 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -624,6 +624,7 @@ struct device {
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
bool dma_coherent:1;
#endif
+ unsigned int group_id;
};

static inline struct device *kobj_to_dev(struct kobject *kobj)
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 9c15b7403694..3890b143b04d 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -135,6 +135,12 @@ enum platform_msi_type {
GEN_PLAT_MSI = 1,
};

+struct platform_msi_group_entry {
+ unsigned int group_id;
+ struct list_head group_list;
+ struct list_head entry_list;
+};
+
/* Helpers to hide struct msi_desc implementation details */
#define msi_desc_to_dev(desc) ((desc)->dev)
#define dev_to_msi_list(dev) (&(dev)->msi_list)
@@ -145,21 +151,31 @@ enum platform_msi_type {
#define for_each_msi_entry_safe(desc, tmp, dev) \
list_for_each_entry_safe((desc), (tmp), dev_to_msi_list((dev)), list)

-#define dev_to_platform_msi_list(dev) (&(dev)->platform_msi_list)
-#define first_platform_msi_entry(dev) \
- list_first_entry(dev_to_platform_msi_list((dev)), struct msi_desc, list)
-#define for_each_platform_msi_entry(desc, dev) \
- list_for_each_entry((desc), dev_to_platform_msi_list((dev)), list)
-#define for_each_platform_msi_entry_safe(desc, tmp, dev) \
- list_for_each_entry_safe((desc), (tmp), dev_to_platform_msi_list((dev)), list)
+#define dev_to_platform_msi_group_list(dev) (&(dev)->platform_msi_list)
+
+#define first_platform_msi_group_entry(dev) \
+ list_first_entry(dev_to_platform_msi_group_list((dev)), \
+ struct platform_msi_group_entry, group_list)

-#define first_msi_entry_common(dev) \
- list_first_entry_select((dev)->platform_msi_type, dev_to_platform_msi_list((dev)), \
+#define platform_msi_current_group_entry_list(dev) \
+ (&((list_last_entry(dev_to_platform_msi_group_list((dev)), \
+ struct platform_msi_group_entry, \
+ group_list))->entry_list))
+
+#define first_msi_entry_current_group(dev) \
+ list_first_entry_select((dev)->platform_msi_type, \
+ platform_msi_current_group_entry_list((dev)), \
dev_to_msi_list((dev)), struct msi_desc, list)

-#define for_each_msi_entry_common(desc, dev) \
- list_for_each_entry_select((dev)->platform_msi_type, desc, dev_to_platform_msi_list((dev)), \
- dev_to_msi_list((dev)), list) \
+#define for_each_msi_entry_current_group(desc, dev) \
+ list_for_each_entry_select((dev)->platform_msi_type, desc, \
+ platform_msi_current_group_entry_list((dev)),\
+ dev_to_msi_list((dev)), list)
+
+#define for_each_platform_msi_entry_in_group(desc, platform_msi_group, group, dev) \
+ list_for_each_entry((platform_msi_group), dev_to_platform_msi_group_list((dev)), group_list) \
+ if (((platform_msi_group)->group_id) == (group)) \
+ list_for_each_entry((desc), (&(platform_msi_group)->entry_list), list)

#ifdef CONFIG_IRQ_MSI_IOMMU
static inline const void *msi_desc_get_iommu_cookie(struct msi_desc *desc)
@@ -363,6 +379,8 @@ struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode,
int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
int nvec);
void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev);
+void msi_domain_free_irqs_group(struct irq_domain *domain,
+ struct device *dev, unsigned int group);
struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain);

struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
@@ -371,6 +389,11 @@ struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
const struct platform_msi_ops *platform_ops);
void platform_msi_domain_free_irqs(struct device *dev);
+int platform_msi_domain_alloc_irqs_group(struct device *dev, unsigned int nvec,
+ const struct platform_msi_ops *platform_ops,
+ unsigned int *group_id);
+void platform_msi_domain_free_irqs_group(struct device *dev,
+ unsigned int group_id);

/* When an MSI domain is used as an intermediate domain */
int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index bc5f9e32387f..899ade394ec8 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -320,7 +320,7 @@ int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
struct msi_desc *desc;
int ret = 0;

- for_each_msi_entry_common(desc, dev) {
+ for_each_msi_entry_current_group(desc, dev) {
/* Don't even try the multi-MSI brain damage. */
if (WARN_ON(!desc->irq || desc->nvec_used != 1)) {
ret = -EINVAL;
@@ -342,7 +342,7 @@ int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,

if (ret) {
/* Mop up the damage */
- for_each_msi_entry_common(desc, dev) {
+ for_each_msi_entry_current_group(desc, dev) {
if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
continue;

@@ -383,7 +383,7 @@ static bool msi_check_reservation_mode(struct irq_domain *domain,
* Checking the first MSI descriptor is sufficient. MSIX supports
* masking and MSI does so when the maskbit is set.
*/
- desc = first_msi_entry_common(dev);
+ desc = first_msi_entry_current_group(dev);
return desc->msi_attrib.is_msix || desc->msi_attrib.maskbit;
}

@@ -411,7 +411,7 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
if (ret)
return ret;

- for_each_msi_entry_common(desc, dev) {
+ for_each_msi_entry_current_group(desc, dev) {
ops->set_desc(&arg, desc);

virq = __irq_domain_alloc_irqs(domain, -1, desc->nvec_used,
@@ -437,7 +437,7 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,

can_reserve = msi_check_reservation_mode(domain, info, dev);

- for_each_msi_entry_common(desc, dev) {
+ for_each_msi_entry_current_group(desc, dev) {
virq = desc->irq;
if (desc->nvec_used == 1)
dev_dbg(dev, "irq %d for MSI\n", virq);
@@ -468,7 +468,7 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
* so request_irq() will assign the final vector.
*/
if (can_reserve) {
- for_each_msi_entry_common(desc, dev) {
+ for_each_msi_entry_current_group(desc, dev) {
irq_data = irq_domain_get_irq_data(domain, desc->irq);
irqd_clr_activated(irq_data);
}
@@ -476,7 +476,7 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
return 0;

cleanup:
- for_each_msi_entry_common(desc, dev) {
+ for_each_msi_entry_current_group(desc, dev) {
struct irq_data *irqd;

if (desc->irq == virq)
@@ -500,7 +500,34 @@ void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
{
struct msi_desc *desc;

- for_each_msi_entry_common(desc, dev) {
+ for_each_msi_entry_current_group(desc, dev) {
+ /*
+ * We might have failed to allocate an MSI early
+ * enough that there is no IRQ associated to this
+ * entry. If that's the case, don't do anything.
+ */
+ if (desc->irq) {
+ irq_domain_free_irqs(desc->irq, desc->nvec_used);
+ desc->irq = 0;
+ }
+ }
+}
+
+/**
+ * msi_domain_free_irqs_group - Free interrupts from a MSI interrupt @domain
+ * associated to @dev from a particular group
+ * @domain: The domain to managing the interrupts
+ * @dev: Pointer to device struct of the device for which the interrupts
+ * are free
+ * @group: group from which interrupts are to be freed
+ */
+void msi_domain_free_irqs_group(struct irq_domain *domain,
+ struct device *dev, unsigned int group)
+{
+ struct msi_desc *desc;
+ struct platform_msi_group_entry *platform_msi_group;
+
+ for_each_platform_msi_entry_in_group(desc, platform_msi_group, group, dev) {
/*
* We might have failed to allocate an MSI early
* enough that there is no IRQ associated to this