[RFC V1 1/7] genirq/msi: Differentiate between various MSI based interrupts

From: Megha Dey
Date: Thu Sep 12 2019 - 21:15:02 EST


Since a device can support both MSI-X and IMS interrupts simultaneously,
do away with is_msix and introduce a new enum msi_desc_tag to
differentiate between the various types of msi_descs.

Signed-off-by: Megha Dey <megha.dey@xxxxxxxxxxxxxxx>
---
arch/mips/pci/msi-xlp.c | 2 +-
arch/s390/pci/pci_irq.c | 2 +-
arch/x86/kernel/apic/msi.c | 2 +-
arch/x86/pci/xen.c | 2 +-
drivers/pci/msi.c | 19 ++++++++++---------
include/linux/msi.h | 11 ++++++++++-
kernel/irq/msi.c | 2 +-
7 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/arch/mips/pci/msi-xlp.c b/arch/mips/pci/msi-xlp.c
index bb14335..0f06ad1 100644
--- a/arch/mips/pci/msi-xlp.c
+++ b/arch/mips/pci/msi-xlp.c
@@ -457,7 +457,7 @@ int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
node = slot / 8;
lnkbase = nlm_get_pcie_base(node, link);

- if (desc->msi_attrib.is_msix)
+ if (desc->tag == IRQ_MSI_TAG_MSIX)
return xlp_setup_msix(lnkbase, node, link, desc);
else
return xlp_setup_msi(lnkbase, node, link, desc);
diff --git a/arch/s390/pci/pci_irq.c b/arch/s390/pci/pci_irq.c
index d80616a..1938582 100644
--- a/arch/s390/pci/pci_irq.c
+++ b/arch/s390/pci/pci_irq.c
@@ -332,7 +332,7 @@ void arch_teardown_msi_irqs(struct pci_dev *pdev)
for_each_pci_msi_entry(msi, pdev) {
if (!msi->irq)
continue;
- if (msi->msi_attrib.is_msix)
+ if (msi->tag == IRQ_MSI_TAG_MSIX)
__pci_msix_desc_mask_irq(msi, 1);
else
__pci_msi_desc_mask_irq(msi, 1, 1);
diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
index 7f75334..435bcda 100644
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -98,7 +98,7 @@ int pci_msi_prepare(struct irq_domain *domain, struct device *dev, int nvec,

init_irq_alloc_info(arg, NULL);
arg->msi_dev = pdev;
- if (desc->msi_attrib.is_msix) {
+ if (desc->tag == IRQ_MSI_TAG_MSIX) {
arg->type = X86_IRQ_ALLOC_TYPE_MSIX;
} else {
arg->type = X86_IRQ_ALLOC_TYPE_MSI;
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 91220cc..5e850b8 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -382,7 +382,7 @@ static void xen_teardown_msi_irqs(struct pci_dev *dev)
struct msi_desc *msidesc;

msidesc = first_pci_msi_entry(dev);
- if (msidesc->msi_attrib.is_msix)
+ if (msidesc->tag == IRQ_MSI_TAG_MSIX)
xen_pci_frontend_disable_msix(dev);
else
xen_pci_frontend_disable_msi(dev);
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 0884bed..8a05416 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -235,7 +235,7 @@ static void msi_set_mask_bit(struct irq_data *data, u32 flag)
{
struct msi_desc *desc = irq_data_get_msi_desc(data);

- if (desc->msi_attrib.is_msix) {
+ if (desc->tag == IRQ_MSI_TAG_MSIX) {
msix_mask_irq(desc, flag);
readl(desc->mask_base); /* Flush write to device */
} else {
@@ -278,7 +278,7 @@ void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg)

BUG_ON(dev->current_state != PCI_D0);

- if (entry->msi_attrib.is_msix) {
+ if (entry->tag == IRQ_MSI_TAG_MSIX) {
void __iomem *base = pci_msix_desc_addr(entry);

if (!base) {
@@ -313,7 +313,7 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)

if (dev->current_state != PCI_D0 || pci_dev_is_disconnected(dev)) {
/* Don't touch the hardware now */
- } else if (entry->msi_attrib.is_msix) {
+ } else if (entry->tag == IRQ_MSI_TAG_MSIX) {
void __iomem *base = pci_msix_desc_addr(entry);

if (!base)
@@ -376,7 +376,7 @@ static void free_msi_irqs(struct pci_dev *dev)
pci_msi_teardown_msi_irqs(dev);

list_for_each_entry_safe(entry, tmp, msi_list, list) {
- if (entry->msi_attrib.is_msix) {
+ if (entry->tag == IRQ_MSI_TAG_MSIX) {
if (list_is_last(&entry->list, msi_list))
iounmap(entry->mask_base);
}
@@ -471,7 +471,7 @@ static ssize_t msi_mode_show(struct device *dev, struct device_attribute *attr,
entry = irq_get_msi_desc(irq);
if (entry)
return sprintf(buf, "%s\n",
- entry->msi_attrib.is_msix ? "msix" : "msi");
+ (entry->tag == IRQ_MSI_TAG_MSIX) ? "msix" : "msi");

return -ENODEV;
}
@@ -570,7 +570,7 @@ msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd)

pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);

- entry->msi_attrib.is_msix = 0;
+ entry->tag = IRQ_MSI_TAG_MSI;
entry->msi_attrib.is_64 = !!(control & PCI_MSI_FLAGS_64BIT);
entry->msi_attrib.is_virtual = 0;
entry->msi_attrib.entry_nr = 0;
@@ -714,7 +714,7 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
goto out;
}

- entry->msi_attrib.is_msix = 1;
+ entry->tag = IRQ_MSI_TAG_MSIX;
entry->msi_attrib.is_64 = 1;
if (entries)
entry->msi_attrib.entry_nr = entries[i].entry;
@@ -1380,7 +1380,7 @@ irq_hw_number_t pci_msi_domain_calc_hwirq(struct pci_dev *dev,

static inline bool pci_msi_desc_is_multi_msi(struct msi_desc *desc)
{
- return !desc->msi_attrib.is_msix && desc->nvec_used > 1;
+ return (desc->tag == IRQ_MSI_TAG_MSI) && desc->nvec_used > 1;
}

/**
@@ -1404,7 +1404,8 @@ int pci_msi_domain_check_cap(struct irq_domain *domain,
if (pci_msi_desc_is_multi_msi(desc) &&
!(info->flags & MSI_FLAG_MULTI_PCI_MSI))
return 1;
- else if (desc->msi_attrib.is_msix && !(info->flags & MSI_FLAG_PCI_MSIX))
+ else if ((desc->tag == IRQ_MSI_TAG_MSIX) &&
+ !(info->flags & MSI_FLAG_PCI_MSIX))
return -ENOTSUPP;

return 0;
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 8ad679e..22591b6 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -55,6 +55,15 @@ struct ti_sci_inta_msi_desc {
u16 dev_index;
};

+enum msi_desc_tags {
+ IRQ_MSI_TAG_MSI,
+ IRQ_MSI_TAG_MSIX,
+ IRQ_MSI_TAG_IMS,
+ IRQ_MSI_TAG_PLAT,
+ IRQ_MSI_TAG_FSL,
+ IRQ_MSI_TAG_SCI,
+};
+
/**
* struct msi_desc - Descriptor structure for MSI based interrupts
* @list: List head for management
@@ -90,6 +99,7 @@ struct msi_desc {
struct device *dev;
struct msi_msg msg;
struct irq_affinity_desc *affinity;
+ enum msi_desc_tags tag;
#ifdef CONFIG_IRQ_MSI_IOMMU
const void *iommu_cookie;
#endif
@@ -102,7 +112,6 @@ struct msi_desc {
struct {
u32 masked;
struct {
- u8 is_msix : 1;
u8 multiple : 3;
u8 multi_cap : 3;
u8 maskbit : 1;
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index ad26fbc..0819395 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -384,7 +384,7 @@ static bool msi_check_reservation_mode(struct irq_domain *domain,
* masking and MSI does so when the maskbit is set.
*/
desc = first_msi_entry(dev);
- return desc->msi_attrib.is_msix || desc->msi_attrib.maskbit;
+ return (desc->tag == IRQ_MSI_TAG_MSIX) || desc->msi_attrib.maskbit;
}

/**
--
2.7.4