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PCI MSI: Fix restoration of MSI/MSI-X mask states in suspend/resume
There are 2 problems on mask states in suspend/resume. [1]: It is better to restore the mask states of MSI/MSI-X to initial states (MSI is unmasked, MSI-X is masked) when we release the device. The pci_msi_shutdown() does the restoration of mask states for MSI, while the msi_free_irqs() does it for MSI-X. In other words, in the "disable" path both of MSI and MSI-X are handled, but in the "shutdown" path only MSI is handled. MSI: pci_disable_msi() => pci_msi_shutdown() [ mask states for MSI restored ] => msi_set_enable(dev, pos, 0); => msi_free_irqs() MSI-X: pci_disable_msix() => pci_msix_shutdown() => msix_set_enable(dev, 0); => msix_free_all_irqs => msi_free_irqs() [ mask states for MSI-X restored ] This patch moves the masking for MSI-X from msi_free_irqs() to pci_msix_shutdown(). This change has some positive side effects: - It prevents OS from touching mask states before reading preserved bits in the register, which can be happen if msi_free_irqs() is called from error path in msix_capability_init(). - It also prevents touching the register after turning off MSI-X in "disable" path, which can be a problem on some devices. [2]: We have cache of the mask state in msi_desc, which is automatically updated when msi/msix_mask_irq() is called. This cached states are used for the resume. But since what need to be restored in the resume is the states before the shutdown on the suspend, calling msi/msix_mask_irq() from pci_msi/msix_shutdown() is not appropriate. This patch introduces __msi/msix_mask_irq() that do mask as same as msi/msix_mask_irq() but does not update cached state, for use in pci_msi/msix_shutdown(). [updated: get rid of msi/msix_mask_irq_nocache() (proposed by Matthew Wilcox)] Reviewed-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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1 changed files with 28 additions and 7 deletions
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@ -127,17 +127,23 @@ static inline __attribute_const__ u32 msi_enabled_mask(u16 control)
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* reliably as devices without an INTx disable bit will then generate a
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* level IRQ which will never be cleared.
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*/
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static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
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static u32 __msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
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{
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u32 mask_bits = desc->masked;
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if (!desc->msi_attrib.maskbit)
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return;
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return 0;
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mask_bits &= ~mask;
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mask_bits |= flag;
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pci_write_config_dword(desc->dev, desc->mask_pos, mask_bits);
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desc->masked = mask_bits;
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return mask_bits;
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}
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static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
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{
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desc->masked = __msi_mask_irq(desc, mask, flag);
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}
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/*
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@ -147,7 +153,7 @@ static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
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* file. This saves a few milliseconds when initialising devices with lots
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* of MSI-X interrupts.
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*/
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static void msix_mask_irq(struct msi_desc *desc, u32 flag)
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static u32 __msix_mask_irq(struct msi_desc *desc, u32 flag)
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{
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u32 mask_bits = desc->masked;
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unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
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@ -155,7 +161,13 @@ static void msix_mask_irq(struct msi_desc *desc, u32 flag)
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mask_bits &= ~1;
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mask_bits |= flag;
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writel(mask_bits, desc->mask_base + offset);
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desc->masked = mask_bits;
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return mask_bits;
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}
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static void msix_mask_irq(struct msi_desc *desc, u32 flag)
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{
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desc->masked = __msix_mask_irq(desc, flag);
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}
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static void msi_set_mask_bit(unsigned irq, u32 flag)
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@ -616,9 +628,11 @@ void pci_msi_shutdown(struct pci_dev *dev)
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pci_intx_for_msi(dev, 1);
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dev->msi_enabled = 0;
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/* Return the device with MSI unmasked as initial states */
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pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &ctrl);
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mask = msi_capable_mask(ctrl);
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msi_mask_irq(desc, mask, ~mask);
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/* Keep cached state to be restored */
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__msi_mask_irq(desc, mask, ~mask);
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/* Restore dev->irq to its default pin-assertion irq */
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dev->irq = desc->msi_attrib.default_irq;
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@ -658,7 +672,6 @@ static int msi_free_irqs(struct pci_dev* dev)
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list_for_each_entry_safe(entry, tmp, &dev->msi_list, list) {
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if (entry->msi_attrib.is_msix) {
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msix_mask_irq(entry, 1);
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if (list_is_last(&entry->list, &dev->msi_list))
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iounmap(entry->mask_base);
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}
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@ -746,9 +759,17 @@ static void msix_free_all_irqs(struct pci_dev *dev)
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void pci_msix_shutdown(struct pci_dev* dev)
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{
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struct msi_desc *entry;
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if (!pci_msi_enable || !dev || !dev->msix_enabled)
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return;
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/* Return the device with MSI-X masked as initial states */
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list_for_each_entry(entry, &dev->msi_list, list) {
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/* Keep cached states to be restored */
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__msix_mask_irq(entry, 1);
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}
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msix_set_enable(dev, 0);
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pci_intx_for_msi(dev, 1);
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dev->msix_enabled = 0;
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