/* * File: msi.c * Purpose: PCI Message Signaled Interrupt (MSI) * * Copyright (C) 2003-2004 Intel * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com) */ #include <linux/err.h> #include <linux/mm.h> #include <linux/irq.h> #include <linux/interrupt.h> #include <linux/init.h> #include <linux/ioport.h> #include <linux/pci.h> #include <linux/proc_fs.h> #include <linux/msi.h> #include <linux/smp.h> #include <linux/errno.h> #include <linux/io.h> #include <linux/slab.h> #include "pci.h" #include "msi.h" static int pci_msi_enable = 1; /* Arch hooks */ #ifndef arch_msi_check_device int arch_msi_check_device(struct pci_dev *dev, int nvec, int type) { return 0; } #endif #ifndef arch_setup_msi_irqs int 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 < 0) return ret; if (ret > 0) return -ENOSPC; } return 0; } #endif #ifndef arch_teardown_msi_irqs void arch_teardown_msi_irqs(struct pci_dev *dev) { struct msi_desc *entry; list_for_each_entry(entry, &dev->msi_list, list) { int i, nvec; if (entry->irq == 0) continue; nvec = 1 << entry->msi_attrib.multiple; for (i = 0; i < nvec; i++) arch_teardown_msi_irq(entry->irq + i); } } #endif static void msi_set_enable(struct pci_dev *dev, int pos, int enable) { u16 control; BUG_ON(!pos); pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control); control &= ~PCI_MSI_FLAGS_ENABLE; if (enable) control |= PCI_MSI_FLAGS_ENABLE; pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control); } static void msix_set_enable(struct pci_dev *dev, int enable) { int pos; u16 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; if (enable) control |= PCI_MSIX_FLAGS_ENABLE; pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control); } } static inline __attribute_const__ u32 msi_mask(unsigned x) { /* Don't shift by >= width of type */ if (x >= 5) return 0xffffffff; return (1 << (1 << x)) - 1; } static inline __attribute_const__ u32 msi_capable_mask(u16 control) { return msi_mask((control >> 1) & 7); } static inline __attribute_const__ u32 msi_enabled_mask(u16 control) { return msi_mask((control >> 4) & 7); } /* * PCI 2.3 does not specify mask bits for each MSI interrupt. Attempting to * mask all MSI interrupts by clearing the MSI enable bit does not work * reliably as devices without an INTx disable bit will then generate a * level IRQ which will never be cleared. */ static u32 __msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag) { u32 mask_bits = desc->masked; if (!desc->msi_attrib.maskbit) return 0; mask_bits &= ~mask; mask_bits |= flag; pci_write_config_dword(desc->dev, desc->mask_pos, mask_bits); return mask_bits; } static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag) { desc->masked = __msi_mask_irq(desc, mask, flag); } /* * This internal function does not flush PCI writes to the device. * All users must ensure that they read from the device before either * assuming that the device state is up to date, or returning out of this * file. This saves a few milliseconds when initialising devices with lots * of MSI-X interrupts. */ static u32 __msix_mask_irq(struct msi_desc *desc, u32 flag) { u32 mask_bits = desc->masked; unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE + PCI_MSIX_ENTRY_VECTOR_CTRL; mask_bits &= ~1; mask_bits |= flag; writel(mask_bits, desc->mask_base + offset); return mask_bits; } static void msix_mask_irq(struct msi_desc *desc, u32 flag) { desc->masked = __msix_mask_irq(desc, flag); } static void msi_set_mask_bit(unsigned irq, u32 flag) { struct msi_desc *desc = get_irq_msi(irq); if (desc->msi_attrib.is_msix) { msix_mask_irq(desc, flag); readl(desc->mask_base); /* Flush write to device */ } else { unsigned offset = irq - desc->dev->irq; msi_mask_irq(desc, 1 << offset, flag << offset); } } void mask_msi_irq(unsigned int irq) { msi_set_mask_bit(irq, 1); } void unmask_msi_irq(unsigned int irq) { msi_set_mask_bit(irq, 0); } void read_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg) { struct msi_desc *entry = get_irq_desc_msi(desc); 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); msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR); msg->data = readl(base + PCI_MSIX_ENTRY_DATA); } else { struct pci_dev *dev = entry->dev; int pos = entry->msi_attrib.pos; u16 data; pci_read_config_dword(dev, msi_lower_address_reg(pos), &msg->address_lo); if (entry->msi_attrib.is_64) { pci_read_config_dword(dev, msi_upper_address_reg(pos), &msg->address_hi); pci_read_config_word(dev, msi_data_reg(pos, 1), &data); } else { msg->address_hi = 0; pci_read_config_word(dev, msi_data_reg(pos, 0), &data); } msg->data = data; } } void read_msi_msg(unsigned int irq, struct msi_msg *msg) { struct irq_desc *desc = irq_to_desc(irq); read_msi_msg_desc(desc, msg); } void write_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg) { struct msi_desc *entry = get_irq_desc_msi(desc); 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); writel(msg->address_hi, base + PCI_MSIX_ENTRY_UPPER_ADDR); writel(msg->data, base + PCI_MSIX_ENTRY_DATA); } 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); if (entry->msi_attrib.is_64) { pci_write_config_dword(dev, msi_upper_address_reg(pos), msg->address_hi); pci_write_config_word(dev, msi_data_reg(pos, 1), msg->data); } else { pci_write_config_word(dev, msi_data_reg(pos, 0), msg->data); } } entry->msg = *msg; } void write_msi_msg(unsigned int irq, struct msi_msg *msg) { struct irq_desc *desc = irq_to_desc(irq); write_msi_msg_desc(desc, msg); } static void free_msi_irqs(struct pci_dev *dev) { struct msi_desc *entry, *tmp; list_for_each_entry(entry, &dev->msi_list, list) { int i, nvec; if (!entry->irq) continue; nvec = 1 << entry->msi_attrib.multiple; for (i = 0; i < nvec; i++) BUG_ON(irq_has_action(entry->irq + i)); } arch_teardown_msi_irqs(dev); list_for_each_entry_safe(entry, tmp, &dev->msi_list, list) { if (entry->msi_attrib.is_msix) { if (list_is_last(&entry->list, &dev->msi_list)) iounmap(entry->mask_base); } list_del(&entry->list); kfree(entry); } } static struct msi_desc *alloc_msi_entry(struct pci_dev *dev) { struct msi_desc *desc = kzalloc(sizeof(*desc), GFP_KERNEL); if (!desc) return NULL; INIT_LIST_HEAD(&desc->list); desc->dev = dev; return desc; } static void pci_intx_for_msi(struct pci_dev *dev, int enable) { if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG)) pci_intx(dev, enable); } static void __pci_restore_msi_state(struct pci_dev *dev) { int pos; u16 control; struct msi_desc *entry; if (!dev->msi_enabled) return; entry = get_irq_msi(dev->irq); pos = entry->msi_attrib.pos; pci_intx_for_msi(dev, 0); msi_set_enable(dev, pos, 0); write_msi_msg(dev->irq, &entry->msg); pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control); msi_mask_irq(entry, msi_capable_mask(control), entry->masked); control &= ~PCI_MSI_FLAGS_QSIZE; control |= (entry->msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE; pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control); } static void __pci_restore_msix_state(struct pci_dev *dev) { int pos; struct msi_desc *entry; u16 control; if (!dev->msix_enabled) return; BUG_ON(list_empty(&dev->msi_list)); entry = list_first_entry(&dev->msi_list, struct msi_desc, list); pos = entry->msi_attrib.pos; pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control); /* route the table */ pci_intx_for_msi(dev, 0); control |= PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL; pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control); list_for_each_entry(entry, &dev->msi_list, list) { write_msi_msg(entry->irq, &entry->msg); msix_mask_irq(entry, entry->masked); } control &= ~PCI_MSIX_FLAGS_MASKALL; pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control); } void pci_restore_msi_state(struct pci_dev *dev) { __pci_restore_msi_state(dev); __pci_restore_msix_state(dev); } 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 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; u16 control; unsigned mask; pos = pci_find_capability(dev, PCI_CAP_ID_MSI); msi_set_enable(dev, pos, 0); /* Disable MSI during set up */ pci_read_config_word(dev, msi_control_reg(pos), &control); /* MSI Entry Initialization */ entry = alloc_msi_entry(dev); if (!entry) return -ENOMEM; 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); entry->msi_attrib.default_irq = dev->irq; /* Save IOAPIC IRQ */ entry->msi_attrib.pos = pos; entry->mask_pos = msi_mask_reg(pos, entry->msi_attrib.is_64); /* All MSIs are unmasked by default, Mask them all */ if (entry->msi_attrib.maskbit) pci_read_config_dword(dev, entry->mask_pos, &entry->masked); mask = msi_capable_mask(control); msi_mask_irq(entry, mask, mask); list_add_tail(&entry->list, &dev->msi_list); /* Configure MSI capability structure */ ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI); if (ret) { msi_mask_irq(entry, mask, ~mask); free_msi_irqs(dev); return ret; } /* Set MSI enabled bits */ pci_intx_for_msi(dev, 0); msi_set_enable(dev, pos, 1); dev->msi_enabled = 1; dev->irq = entry->irq; return 0; } static void __iomem *msix_map_region(struct pci_dev *dev, unsigned pos, unsigned nr_entries) { unsigned long phys_addr; u32 table_offset; u8 bir; pci_read_config_dword(dev, msix_table_offset_reg(pos), &table_offset); bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK); table_offset &= ~PCI_MSIX_FLAGS_BIRMASK; phys_addr = pci_resource_start(dev, bir) + table_offset; return ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE); } static int msix_setup_entries(struct pci_dev *dev, unsigned pos, void __iomem *base, struct msix_entry *entries, int nvec) { struct msi_desc *entry; int i; for (i = 0; i < nvec; i++) { entry = alloc_msi_entry(dev); if (!entry) { if (!i) iounmap(base); else free_msi_irqs(dev); /* No enough memory. Don't try again */ return -ENOMEM; } entry->msi_attrib.is_msix = 1; entry->msi_attrib.is_64 = 1; entry->msi_attrib.entry_nr = entries[i].entry; entry->msi_attrib.default_irq = dev->irq; entry->msi_attrib.pos = pos; entry->mask_base = base; list_add_tail(&entry->list, &dev->msi_list); } return 0; } static void msix_program_entries(struct pci_dev *dev, struct msix_entry *entries) { struct msi_desc *entry; int i = 0; list_for_each_entry(entry, &dev->msi_list, list) { int offset = entries[i].entry * PCI_MSIX_ENTRY_SIZE + PCI_MSIX_ENTRY_VECTOR_CTRL; entries[i].vector = entry->irq; set_irq_msi(entry->irq, entry); entry->masked = readl(entry->mask_base + offset); msix_mask_irq(entry, 1); i++; } } /** * msix_capability_init - configure device's MSI-X capability * @dev: pointer to the pci_dev data structure of MSI-X device function * @entries: pointer to an array of struct msix_entry entries * @nvec: number of @entries * * Setup the MSI-X capability structure of device function with a * single MSI-X irq. A return of zero indicates the successful setup of * requested MSI-X entries with allocated irqs or non-zero for otherwise. **/ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, int nvec) { int pos, ret; u16 control; void __iomem *base; pos = pci_find_capability(dev, PCI_CAP_ID_MSIX); pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control); /* Ensure MSI-X is disabled while it is set up */ control &= ~PCI_MSIX_FLAGS_ENABLE; pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control); /* Request & Map MSI-X table region */ base = msix_map_region(dev, pos, multi_msix_capable(control)); if (!base) return -ENOMEM; ret = msix_setup_entries(dev, pos, base, entries, nvec); if (ret) return ret; ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); if (ret) goto error; /* * Some devices require MSI-X to be enabled before we can touch the * MSI-X registers. We need to mask all the vectors to prevent * interrupts coming in before they're fully set up. */ control |= PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE; pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control); msix_program_entries(dev, entries); /* Set MSI-X enabled bits and unmask the function */ pci_intx_for_msi(dev, 0); dev->msix_enabled = 1; control &= ~PCI_MSIX_FLAGS_MASKALL; pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control); return 0; error: if (ret < 0) { /* * If we had some success, report the number of irqs * we succeeded in setting up. */ struct msi_desc *entry; int avail = 0; list_for_each_entry(entry, &dev->msi_list, list) { if (entry->irq != 0) avail++; } if (avail != 0) ret = avail; } free_msi_irqs(dev); return ret; } /** * pci_msi_check_device - check whether MSI may be enabled on a device * @dev: pointer to the pci_dev data structure of MSI device function * @nvec: how many MSIs have been requested ? * @type: are we checking for MSI or MSI-X ? * * Look at global flags, the device itself, and its parent busses * to determine if MSI/-X are supported for the device. If MSI/-X is * supported return 0, else return an error code. **/ static int pci_msi_check_device(struct pci_dev *dev, int nvec, int type) { struct pci_bus *bus; int ret; /* MSI must be globally enabled and supported by the device */ if (!pci_msi_enable || !dev || dev->no_msi) return -EINVAL; /* * You can't ask to have 0 or less MSIs configured. * a) it's stupid .. * b) the list manipulation code assumes nvec >= 1. */ if (nvec < 1) return -ERANGE; /* * Any bridge which does NOT route MSI transactions from its * secondary bus to its primary bus must set NO_MSI flag on * the secondary pci_bus. * We expect only arch-specific PCI host bus controller driver * or quirks for specific PCI bridges to be setting NO_MSI. */ for (bus = dev->bus; bus; bus = bus->parent) if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI) return -EINVAL; ret = arch_msi_check_device(dev, nvec, type); if (ret) return ret; if (!pci_find_capability(dev, type)) return -EINVAL; return 0; } /** * pci_enable_msi_block - configure device's MSI capability structure * @dev: device to configure * @nvec: number of interrupts to configure * * 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 interrupts requested, it returns 0 and * updates the @dev's irq member to the lowest new interrupt number; the * other interrupt numbers allocated to this device are consecutive. */ int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec) { 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, nvec, PCI_CAP_ID_MSI); if (status) return status; WARN_ON(!!dev->msi_enabled); /* Check whether driver already requested MSI-X irqs */ if (dev->msix_enabled) { dev_info(&dev->dev, "can't enable MSI " "(MSI-X already enabled)\n"); return -EINVAL; } status = msi_capability_init(dev, nvec); return status; } EXPORT_SYMBOL(pci_enable_msi_block); void pci_msi_shutdown(struct pci_dev *dev) { struct msi_desc *desc; u32 mask; u16 ctrl; unsigned pos; if (!pci_msi_enable || !dev || !dev->msi_enabled) return; BUG_ON(list_empty(&dev->msi_list)); desc = list_first_entry(&dev->msi_list, struct msi_desc, list); pos = desc->msi_attrib.pos; msi_set_enable(dev, pos, 0); pci_intx_for_msi(dev, 1); dev->msi_enabled = 0; /* Return the device with MSI unmasked as initial states */ pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &ctrl); mask = msi_capable_mask(ctrl); /* Keep cached state to be restored */ __msi_mask_irq(desc, mask, ~mask); /* Restore dev->irq to its default pin-assertion irq */ dev->irq = desc->msi_attrib.default_irq; } void pci_disable_msi(struct pci_dev *dev) { if (!pci_msi_enable || !dev || !dev->msi_enabled) return; pci_msi_shutdown(dev); free_msi_irqs(dev); } EXPORT_SYMBOL(pci_disable_msi); /** * pci_msix_table_size - return the number of device's MSI-X table entries * @dev: pointer to the pci_dev data structure of MSI-X device function */ int pci_msix_table_size(struct pci_dev *dev) { int pos; u16 control; pos = pci_find_capability(dev, PCI_CAP_ID_MSIX); if (!pos) return 0; pci_read_config_word(dev, msi_control_reg(pos), &control); return multi_msix_capable(control); } /** * pci_enable_msix - configure device's MSI-X capability structure * @dev: pointer to the pci_dev data structure of MSI-X device function * @entries: pointer to an array of MSI-X entries * @nvec: number of MSI-X irqs requested for allocation by device driver * * Setup the MSI-X capability structure of device function with the number * of requested irqs upon its software driver call to request for * MSI-X mode enabled on its hardware device function. A return of zero * indicates the successful configuration of MSI-X capability structure * with new allocated MSI-X irqs. A return of < 0 indicates a failure. * Or a return of > 0 indicates that driver request is exceeding the number * of irqs or MSI-X vectors available. Driver should use the returned value to * re-send its request. **/ int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec) { int status, nr_entries; int i, j; if (!entries) return -EINVAL; status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSIX); if (status) return status; nr_entries = pci_msix_table_size(dev); if (nvec > nr_entries) return nr_entries; /* Check for any invalid entries */ for (i = 0; i < nvec; i++) { if (entries[i].entry >= nr_entries) return -EINVAL; /* invalid entry */ for (j = i + 1; j < nvec; j++) { if (entries[i].entry == entries[j].entry) return -EINVAL; /* duplicate entry */ } } WARN_ON(!!dev->msix_enabled); /* Check whether driver already requested for MSI irq */ if (dev->msi_enabled) { dev_info(&dev->dev, "can't enable MSI-X " "(MSI IRQ already assigned)\n"); return -EINVAL; } status = msix_capability_init(dev, entries, nvec); return status; } EXPORT_SYMBOL(pci_enable_msix); void pci_msix_shutdown(struct pci_dev *dev) { struct msi_desc *entry; if (!pci_msi_enable || !dev || !dev->msix_enabled) return; /* Return the device with MSI-X masked as initial states */ list_for_each_entry(entry, &dev->msi_list, list) { /* Keep cached states to be restored */ __msix_mask_irq(entry, 1); } msix_set_enable(dev, 0); pci_intx_for_msi(dev, 1); dev->msix_enabled = 0; } void pci_disable_msix(struct pci_dev *dev) { if (!pci_msi_enable || !dev || !dev->msix_enabled) return; pci_msix_shutdown(dev); free_msi_irqs(dev); } EXPORT_SYMBOL(pci_disable_msix); /** * msi_remove_pci_irq_vectors - reclaim MSI(X) irqs to unused state * @dev: pointer to the pci_dev data structure of MSI(X) device function * * Being called during hotplug remove, from which the device function * is hot-removed. All previous assigned MSI/MSI-X irqs, if * allocated for this device function, are reclaimed to unused state, * which may be used later on. **/ void msi_remove_pci_irq_vectors(struct pci_dev *dev) { if (!pci_msi_enable || !dev) return; if (dev->msi_enabled || dev->msix_enabled) free_msi_irqs(dev); } void pci_no_msi(void) { pci_msi_enable = 0; } /** * pci_msi_enabled - is MSI enabled? * * Returns true if MSI has not been disabled by the command-line option * pci=nomsi. **/ int pci_msi_enabled(void) { return pci_msi_enable; } EXPORT_SYMBOL(pci_msi_enabled); void pci_msi_init_pci_dev(struct pci_dev *dev) { INIT_LIST_HEAD(&dev->msi_list); }