[PATCH 1/3] msi: Sanely support hardware level msi disabling.
From: Eric W. Biederman
Date: Tue Feb 27 2007 - 14:29:31 EST
In some cases when we are not using msi we need a way to ensure that
the hardware does not have an msi capability enabled. Currently the
code has been calling disable_msi_mode to try and achieve that.
However disable_msi_mode has several other side effects and is only
available when msi support is compiled in so it isn't really
appropriate.
Instead this patch implements pci_msi_off which disables all msi and
msix capabilities unconditionally with no additional side effects.
pci_disable_device was redundantly clearing the bus master enable flag
and clearing the msi enable bit. A device that is not allowed to
perform bus mastering operations cannot generate intx or msi interrupt
messages as those are essentially a special case of dma, and require
bus mastering. So the call in pci_disable_device to disable msi
capabilities was redundant.
quirk_pcie_pxh also called disable_msi_mode and is updated to use
pci_msi_off.
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
---
arch/powerpc/kernel/irq.c | 1 -
drivers/pci/msi.c | 2 +-
drivers/pci/pci.c | 34 +++++++++++++++++++++++++++-------
drivers/pci/pci.h | 2 --
drivers/pci/quirks.c | 4 ++--
include/linux/pci.h | 1 +
include/linux/pci_regs.h | 7 ++++---
7 files changed, 35 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 919fbf5..1009308 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -968,7 +968,6 @@ void pci_scan_msi_device(struct pci_dev *dev) {}
int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec) {return -1;}
void pci_disable_msix(struct pci_dev *dev) {}
void msi_remove_pci_irq_vectors(struct pci_dev *dev) {}
-void disable_msi_mode(struct pci_dev *dev, int pos, int type) {}
void pci_no_msi(void) {}
EXPORT_SYMBOL(pci_enable_msix);
EXPORT_SYMBOL(pci_disable_msix);
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 68555c1..fd1068b 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -211,7 +211,7 @@ static void enable_msi_mode(struct pci_dev *dev, int pos, int type)
pci_intx(dev, 0); /* disable intx */
}
-void disable_msi_mode(struct pci_dev *dev, int pos, int type)
+static void disable_msi_mode(struct pci_dev *dev, int pos, int type)
{
u16 control;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1e74e1e..bd44a48 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -881,13 +881,6 @@ pci_disable_device(struct pci_dev *dev)
if (atomic_sub_return(1, &dev->enable_cnt) != 0)
return;
- if (dev->msi_enabled)
- disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
- PCI_CAP_ID_MSI);
- if (dev->msix_enabled)
- disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
- PCI_CAP_ID_MSIX);
-
pci_read_config_word(dev, PCI_COMMAND, &pci_command);
if (pci_command & PCI_COMMAND_MASTER) {
pci_command &= ~PCI_COMMAND_MASTER;
@@ -1277,6 +1270,33 @@ pci_intx(struct pci_dev *pdev, int enable)
}
}
+/**
+ * pci_msi_off - disables any msi or msix capabilities
+ * @pdev: the PCI device to operate on
+ *
+ * If you want to use msi see pci_enable_msi and friends.
+ * This is a lower level primitive that allows us to disable
+ * msi operation at the device level.
+ */
+void pci_msi_off(struct pci_dev *dev)
+{
+ int pos;
+ u16 control;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
+ if (pos) {
+ pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
+ control &= ~PCI_MSI_FLAGS_ENABLE;
+ pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
+ }
+ pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
+ if (pos) {
+ pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
+ control &= ~PCI_MSIX_FLAGS_ENABLE;
+ pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
+ }
+}
+
#ifndef HAVE_ARCH_PCI_SET_DMA_MASK
/*
* These can be overridden by arch-specific implementations
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index a4f2d58..ae7a975 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -46,10 +46,8 @@ extern struct rw_semaphore pci_bus_sem;
extern unsigned int pci_pm_d3_delay;
#ifdef CONFIG_PCI_MSI
-void disable_msi_mode(struct pci_dev *dev, int pos, int type);
void pci_no_msi(void);
#else
-static inline void disable_msi_mode(struct pci_dev *dev, int pos, int type) { }
static inline void pci_no_msi(void) { }
#endif
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 1e6eda2..e9f9d3b 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1415,8 +1415,8 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_E7525_MCH, quir
*/
static void __devinit quirk_pcie_pxh(struct pci_dev *dev)
{
- disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
- PCI_CAP_ID_MSI);
+ pci_msi_off(dev);
+
dev->no_msi = 1;
printk(KERN_WARNING "PCI: PXH quirk detected, "
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 2c4b684..78417e4 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -543,6 +543,7 @@ void pci_set_master(struct pci_dev *dev);
int __must_check pci_set_mwi(struct pci_dev *dev);
void pci_clear_mwi(struct pci_dev *dev);
void pci_intx(struct pci_dev *dev, int enable);
+void pci_msi_off(struct pci_dev *dev);
int pci_set_dma_mask(struct pci_dev *dev, u64 mask);
int pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask);
void pci_update_resource(struct pci_dev *dev, struct resource *res, int resno);
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index 7a6d34e..f09cce2 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -292,9 +292,10 @@
#define PCI_MSI_DATA_64 12 /* 16 bits of data for 64-bit devices */
#define PCI_MSI_MASK_BIT 16 /* Mask bits register */
-/* MSI-X registers (these are at offset PCI_MSI_FLAGS) */
-#define PCI_MSIX_FLAGS_QSIZE 0x7FF
-#define PCI_MSIX_FLAGS_ENABLE (1 << 15)
+/* MSI-X registers (these are at offset PCI_MSIX_FLAGS) */
+#define PCI_MSIX_FLAGS 2
+#define PCI_MSIX_FLAGS_QSIZE 0x7FF
+#define PCI_MSIX_FLAGS_ENABLE (1 << 15)
#define PCI_MSIX_FLAGS_BIRMASK (7 << 0)
#define PCI_MSIX_FLAGS_BITMASK (1 << 0)
--
1.5.0.g53756
-
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