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Message-Id: <1215811018-15270-3-git-send-email-matthew@wil.cx>
Date: Fri, 11 Jul 2008 17:16:55 -0400
From: Matthew Wilcox <matthew@....cx>
To: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: grundler@...isc-linux.org, mingo@...e.hu, tglx@...utronix.de,
jgarzik@...ox.com, linux-ide@...r.kernel.org,
suresh.b.siddha@...el.com, benh@...nel.crashing.org,
jbarnes@...tuousgeek.org, rdunlap@...otime.net,
mtk.manpages@...il.com, ebiederm@...ssion.com,
Matthew Wilcox <matthew@....cx>,
Matthew Wilcox <willy@...ux.intel.com>
Subject: [PATCH 3/6] PCI MSI: Add support for multiple messages
Add the new API pci_enable_msi_block() to allow drivers to
request multiple MSI and reimplement pci_enable_msi in terms of
pci_enable_msi_block. Ensure that the architecture back ends don't
have to know about multiple MSI.
Signed-off-by: Matthew Wilcox <willy@...ux.intel.com>
---
arch/powerpc/kernel/msi.c | 4 ++
drivers/pci/msi.c | 69 +++++++++++++++++++++++++++++++-------------
drivers/pci/msi.h | 4 --
include/linux/msi.h | 1 +
include/linux/pci.h | 6 ++-
5 files changed, 57 insertions(+), 27 deletions(-)
diff --git a/arch/powerpc/kernel/msi.c b/arch/powerpc/kernel/msi.c
index c62d101..5bc8dda 100644
--- a/arch/powerpc/kernel/msi.c
+++ b/arch/powerpc/kernel/msi.c
@@ -19,6 +19,10 @@ int arch_msi_check_device(struct pci_dev* dev, int nvec, int type)
return -ENOSYS;
}
+ /* PowerPC doesn't support multiple MSI yet */
+ if (type == PCI_CAP_ID_MSI && nvec > 1)
+ return 1;
+
if (ppc_md.msi_check_device) {
pr_debug("msi: Using platform check routine.\n");
return ppc_md.msi_check_device(dev, nvec, type);
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 104f297..853a0f2 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -45,6 +45,13 @@ arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
struct msi_desc *entry;
int ret;
+ /*
+ * If an architecture wants to support multiple MSI, it needs to
+ * override arch_setup_msi_irqs()
+ */
+ if (type == PCI_CAP_ID_MSI && nvec > 1)
+ return 1;
+
list_for_each_entry(entry, &dev->msi_list, list) {
ret = arch_setup_msi_irq(dev, entry);
if (ret)
@@ -186,6 +193,12 @@ void write_msi_msg(unsigned int irq, struct msi_msg *msg)
} else {
struct pci_dev *dev = entry->dev;
int pos = entry->msi_attrib.pos;
+ u16 msgctl;
+
+ pci_read_config_word(dev, msi_control_reg(pos), &msgctl);
+ msgctl &= ~PCI_MSI_FLAGS_QSIZE;
+ msgctl |= entry->msi_attrib.multiple << 4;
+ pci_write_config_word(dev, msi_control_reg(pos), msgctl);
pci_write_config_dword(dev, msi_lower_address_reg(pos),
msg->address_lo);
@@ -301,13 +314,15 @@ EXPORT_SYMBOL_GPL(pci_restore_msi_state);
/**
* msi_capability_init - configure device's MSI capability structure
* @dev: pointer to the pci_dev data structure of MSI device function
+ * @nvec: number of interrupts to allocate
*
- * Setup the MSI capability structure of device function with a single
- * MSI irq, regardless of device function is capable of handling
- * multiple messages. A return of zero indicates the successful setup
- * of an entry zero with the new MSI irq or non-zero for otherwise.
- **/
-static int msi_capability_init(struct pci_dev *dev)
+ * Setup the MSI capability structure of the device with the requested
+ * number of interrupts. A return value of zero indicates the successful
+ * setup of an entry with the new MSI irq. A negative return value indicates
+ * an error, and a positive return value indicates the number of interrupts
+ * which could have been allocated.
+ */
+static int msi_capability_init(struct pci_dev *dev, int nvec)
{
struct msi_desc *entry;
int pos, ret;
@@ -351,7 +366,7 @@ static int msi_capability_init(struct pci_dev *dev)
list_add_tail(&entry->list, &dev->msi_list);
/* Configure MSI capability structure */
- ret = arch_setup_msi_irqs(dev, 1, PCI_CAP_ID_MSI);
+ ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
if (ret) {
msi_free_irqs(dev);
return ret;
@@ -503,36 +518,48 @@ static int pci_msi_check_device(struct pci_dev* dev, int nvec, int type)
}
/**
- * pci_enable_msi - configure device's MSI capability structure
- * @dev: pointer to the pci_dev data structure of MSI device function
+ * pci_enable_msi_block - configure device's MSI capability structure
+ * @dev: device to configure
+ * @nvec: number of interrupts to configure
*
- * Setup the MSI capability structure of device function with
- * a single MSI irq upon its software driver call to request for
- * MSI mode enabled on its hardware device function. A return of zero
- * indicates the successful setup of an entry zero with the new MSI
- * irq or non-zero for otherwise.
- **/
-int pci_enable_msi(struct pci_dev* dev)
+ * Allocate IRQs for a device with the MSI capability.
+ * This function returns a negative errno if an error occurs. If it
+ * is unable to allocate the number of interrupts requested, it returns
+ * the number of interrupts it might be able to allocate. If it successfully
+ * allocates at least the number of interrupt vectors requested, it returns
+ * 0 and updates the @dev's irq member to the new interrupt number.
+ */
+int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
{
- int status;
+ int status, pos, maxvec;
+ u16 msgctl;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
+ if (!pos)
+ return -EINVAL;
+ pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
+ maxvec = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
+ if (nvec > maxvec)
+ return maxvec;
- status = pci_msi_check_device(dev, 1, PCI_CAP_ID_MSI);
+ status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSI);
if (status)
return status;
WARN_ON(!!dev->msi_enabled);
- /* Check whether driver already requested for MSI-X irqs */
+ /* Check whether driver already requested MSI-X irqs */
if (dev->msix_enabled) {
printk(KERN_INFO "PCI: %s: Can't enable MSI. "
"Device already has MSI-X enabled\n",
pci_name(dev));
return -EINVAL;
}
- status = msi_capability_init(dev);
+
+ status = msi_capability_init(dev, nvec);
return status;
}
-EXPORT_SYMBOL(pci_enable_msi);
+EXPORT_SYMBOL(pci_enable_msi_block);
void pci_msi_shutdown(struct pci_dev* dev)
{
diff --git a/drivers/pci/msi.h b/drivers/pci/msi.h
index 3898f52..b72e0bd 100644
--- a/drivers/pci/msi.h
+++ b/drivers/pci/msi.h
@@ -22,12 +22,8 @@
#define msi_disable(control) control &= ~PCI_MSI_FLAGS_ENABLE
#define multi_msi_capable(control) \
(1 << ((control & PCI_MSI_FLAGS_QMASK) >> 1))
-#define multi_msi_enable(control, num) \
- control |= (((num >> 1) << 4) & PCI_MSI_FLAGS_QSIZE);
#define is_64bit_address(control) (!!(control & PCI_MSI_FLAGS_64BIT))
#define is_mask_bit_support(control) (!!(control & PCI_MSI_FLAGS_MASKBIT))
-#define msi_enable(control, num) multi_msi_enable(control, num); \
- control |= PCI_MSI_FLAGS_ENABLE
#define msix_table_offset_reg(base) (base + 0x04)
#define msix_pba_offset_reg(base) (base + 0x08)
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 13a8a1b..70fcebc 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -18,6 +18,7 @@ extern void write_msi_msg(unsigned int irq, struct msi_msg *msg);
struct msi_desc {
struct {
__u8 is_msix : 1;
+ __u8 multiple: 3; /* log2 number of messages */
__u8 maskbit : 1; /* mask-pending bit supported ? */
__u8 masked : 1;
__u8 is_64 : 1; /* Address size: 0=32bit 1=64bit */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d18b1dd..16df5f9 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -699,7 +699,7 @@ struct msix_entry {
#ifndef CONFIG_PCI_MSI
-static inline int pci_enable_msi(struct pci_dev *dev)
+static inline int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
{
return -1;
}
@@ -726,7 +726,7 @@ static inline void msi_remove_pci_irq_vectors(struct pci_dev *dev)
static inline void pci_restore_msi_state(struct pci_dev *dev)
{ }
#else
-extern int pci_enable_msi(struct pci_dev *dev);
+extern int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec);
extern void pci_msi_shutdown(struct pci_dev *dev);
extern void pci_disable_msi(struct pci_dev *dev);
extern int pci_enable_msix(struct pci_dev *dev,
@@ -737,6 +737,8 @@ extern void msi_remove_pci_irq_vectors(struct pci_dev *dev);
extern void pci_restore_msi_state(struct pci_dev *dev);
#endif
+#define pci_enable_msi(pdev) pci_enable_msi_block(pdev, 1)
+
#ifdef CONFIG_HT_IRQ
/* The functions a driver should call */
int ht_create_irq(struct pci_dev *dev, int idx);
--
1.5.5.4
--
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