[PATCH] PCI MSI: Replace 'type' with 'is_msix'

From: Matthew Wilcox
Date: Thu Jul 10 2008 - 21:03:11 EST

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By changing from a 5-bit field to a 1-bit field, we free up some bits
that can be used by a later patch. Also rearrange the fields for better
packing on 64-bit platforms (reducing the size of msi_desc from 72 bytes
to 64 bytes).

Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
---
drivers/pci/msi.c | 100 ++++++++++++++++----------------------------------
include/linux/msi.h | 4 +-
2 files changed, 34 insertions(+), 70 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 8c61304..104f297 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -106,20 +106,10 @@ static void msix_flush_writes(unsigned int irq)

entry = get_irq_msi(irq);
BUG_ON(!entry || !entry->dev);
- switch (entry->msi_attrib.type) {
- case PCI_CAP_ID_MSI:
- /* nothing to do */
- break;
- case PCI_CAP_ID_MSIX:
- {
+ if (entry->msi_attrib.is_msix) {
int offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
readl(entry->mask_base + offset);
- break;
- }
- default:
- BUG();
- break;
}
}

@@ -129,8 +119,12 @@ static void msi_set_mask_bits(unsigned int irq, u32 mask, u32 flag)

entry = get_irq_msi(irq);
BUG_ON(!entry || !entry->dev);
- switch (entry->msi_attrib.type) {
- case PCI_CAP_ID_MSI:
+ if (entry->msi_attrib.is_msix) {
+ int offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
+ writel(flag, entry->mask_base + offset);
+ readl(entry->mask_base + offset);
+ } else {
if (entry->msi_attrib.maskbit) {
int pos;
u32 mask_bits;
@@ -143,18 +137,6 @@ static void msi_set_mask_bits(unsigned int irq, u32 mask, u32 flag)
} else {
msi_set_enable(entry->dev, !flag);
}
- break;
- case PCI_CAP_ID_MSIX:
- {
- int offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
- PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
- writel(flag, entry->mask_base + offset);
- readl(entry->mask_base + offset);
- break;
- }
- default:
- BUG();
- break;
}
entry->msi_attrib.masked = !!flag;
}
@@ -162,9 +144,14 @@ static void msi_set_mask_bits(unsigned int irq, u32 mask, u32 flag)
void read_msi_msg(unsigned int irq, struct msi_msg *msg)
{
struct msi_desc *entry = get_irq_msi(irq);
- switch(entry->msi_attrib.type) {
- case PCI_CAP_ID_MSI:
- {
+ if (entry->msi_attrib.is_msix) {
+ void __iomem *base = entry->mask_base +
+ entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
+
+ msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
+ msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
+ msg->data = readl(base + PCI_MSIX_ENTRY_DATA_OFFSET);
+ } else {
struct pci_dev *dev = entry->dev;
int pos = entry->msi_attrib.pos;
u16 data;
@@ -180,30 +167,23 @@ void read_msi_msg(unsigned int irq, struct msi_msg *msg)
pci_read_config_word(dev, msi_data_reg(pos, 0), &data);
}
msg->data = data;
- break;
- }
- case PCI_CAP_ID_MSIX:
- {
- void __iomem *base;
- base = entry->mask_base +
- entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
-
- msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
- msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
- msg->data = readl(base + PCI_MSIX_ENTRY_DATA_OFFSET);
- break;
- }
- default:
- BUG();
}
}

void write_msi_msg(unsigned int irq, struct msi_msg *msg)
{
struct msi_desc *entry = get_irq_msi(irq);
- switch (entry->msi_attrib.type) {
- case PCI_CAP_ID_MSI:
- {
+ if (entry->msi_attrib.is_msix) {
+ void __iomem *base;
+ base = entry->mask_base +
+ entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
+
+ writel(msg->address_lo,
+ base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
+ writel(msg->address_hi,
+ base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
+ writel(msg->data, base + PCI_MSIX_ENTRY_DATA_OFFSET);
+ } else {
struct pci_dev *dev = entry->dev;
int pos = entry->msi_attrib.pos;

@@ -218,23 +198,6 @@ void write_msi_msg(unsigned int irq, struct msi_msg *msg)
pci_write_config_word(dev, msi_data_reg(pos, 0),
msg->data);
}
- break;
- }
- case PCI_CAP_ID_MSIX:
- {
- void __iomem *base;
- base = entry->mask_base +
- entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
-
- writel(msg->address_lo,
- base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
- writel(msg->address_hi,
- base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
- writel(msg->data, base + PCI_MSIX_ENTRY_DATA_OFFSET);
- break;
- }
- default:
- BUG();
}
entry->msg = *msg;
}
@@ -359,7 +322,7 @@ static int msi_capability_init(struct pci_dev *dev)
if (!entry)
return -ENOMEM;

- entry->msi_attrib.type = PCI_CAP_ID_MSI;
+ entry->msi_attrib.is_msix = 0;
entry->msi_attrib.is_64 = is_64bit_address(control);
entry->msi_attrib.entry_nr = 0;
entry->msi_attrib.maskbit = is_mask_bit_support(control);
@@ -446,7 +409,7 @@ static int msix_capability_init(struct pci_dev *dev,
break;

j = entries[i].entry;
- entry->msi_attrib.type = PCI_CAP_ID_MSIX;
+ entry->msi_attrib.is_msix = 1;
entry->msi_attrib.is_64 = 1;
entry->msi_attrib.entry_nr = j;
entry->msi_attrib.maskbit = 1;
@@ -589,12 +552,13 @@ void pci_msi_shutdown(struct pci_dev* dev)
u32 mask = entry->msi_attrib.maskbits_mask;
msi_set_mask_bits(dev->irq, mask, ~mask);
}
- if (!entry->dev || entry->msi_attrib.type != PCI_CAP_ID_MSI)
+ if (!entry->dev || entry->msi_attrib.is_msix)
return;

/* Restore dev->irq to its default pin-assertion irq */
dev->irq = entry->msi_attrib.default_irq;
}
+
void pci_disable_msi(struct pci_dev* dev)
{
struct msi_desc *entry;
@@ -605,7 +569,7 @@ void pci_disable_msi(struct pci_dev* dev)
pci_msi_shutdown(dev);

entry = list_entry(dev->msi_list.next, struct msi_desc, list);
- if (!entry->dev || entry->msi_attrib.type != PCI_CAP_ID_MSI)
+ if (!entry->dev || entry->msi_attrib.is_msix)
return;

msi_free_irqs(dev);
@@ -624,7 +588,7 @@ static int msi_free_irqs(struct pci_dev* dev)
arch_teardown_msi_irqs(dev);

list_for_each_entry_safe(entry, tmp, &dev->msi_list, list) {
- if (entry->msi_attrib.type == PCI_CAP_ID_MSIX) {
+ if (entry->msi_attrib.is_msix) {
writel(1, entry->mask_base + entry->msi_attrib.entry_nr
* PCI_MSIX_ENTRY_SIZE
+ PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 8f29392..13a8a1b 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -17,13 +17,13 @@ extern void write_msi_msg(unsigned int irq, struct msi_msg *msg);

struct msi_desc {
struct {
- __u8 type : 5; /* {0: unused, 5h:MSI, 11h:MSI-X} */
+ __u8 is_msix : 1;
__u8 maskbit : 1; /* mask-pending bit supported ? */
__u8 masked : 1;
__u8 is_64 : 1; /* Address size: 0=32bit 1=64bit */
__u8 pos; /* Location of the msi capability */
- __u32 maskbits_mask; /* mask bits mask */
__u16 entry_nr; /* specific enabled entry */
+ __u32 maskbits_mask; /* mask bits mask */
unsigned default_irq; /* default pre-assigned irq */
}msi_attrib;

--
1.5.5.4

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Next message: Matthew Wilcox: "[PATCH] AHCI: Request multiple MSIs"
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In reply to: Kenji Kaneshige: "Re: [PATCH] x86-64: Support for multiple MSIs"
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