From f5f2b13129a6541debf8851bae843cbbf48298b7 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 5 Mar 2007 00:30:07 -0800 Subject: [PATCH] [PATCH] msi: sanely support hardware level msi disabling 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 Cc: Michael Ellerman Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 919fbf5684..1009308268 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 68555c11f5..fd1068b59b 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 1e74e1ee8b..df495300ce 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 a4f2d58062..ae7a975995 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 1bf5482875..7f94fc098c 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -1438,8 +1438,8 @@ 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 2c4b6842df..78417e421b 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 7a6d34ee5a..f09cce2357 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) -- 2.39.5