From: Jonathan Currier <dullfire@xxxxxxxxx>
Commit 7d5ec3d36123 ("PCI/MSI: Mask all unused MSI-X entries")
introduces a readl() from ENTRY_VECTOR_CTRL before the writel() to
ENTRY_DATA. This is correct, however some hardware, like the Sun Neptune
chips, the niu module, will cause an error and/or fatal trap if any MSIX
table entry is read before the corresponding ENTRY_DATA field is written
to. This patch adds an optional early writel() in msix_prepare_msi_desc().
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jonathan Currier <dullfire@xxxxxxxxx>
---
drivers/pci/msi/msi.c | 2 ++
include/linux/pci.h | 2 ++
2 files changed, 4 insertions(+)
diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 3a45879d85db..50d87fb5e37f 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -611,6 +611,8 @@ void msix_prepare_msi_desc(struct pci_dev *dev, struct msi_desc *desc)
if (desc->pci.msi_attrib.can_mask) {
void __iomem *addr = pci_msix_desc_addr(desc);
+ if (dev->dev_flags & PCI_DEV_FLAGS_MSIX_TOUCH_ENTRY_DATA_FIRST)
+ writel(0, addr + PCI_MSIX_ENTRY_DATA);
desc->pci.msix_ctrl = readl(addr + PCI_MSIX_ENTRY_VECTOR_CTRL);
}
}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 37d97bef060f..b8b95b58d522 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -245,6 +245,8 @@ enum pci_dev_flags {
PCI_DEV_FLAGS_NO_RELAXED_ORDERING = (__force pci_dev_flags_t) (1 << 11),
/* Device does honor MSI masking despite saying otherwise */
PCI_DEV_FLAGS_HAS_MSI_MASKING = (__force pci_dev_flags_t) (1 << 12),
+ /* Device requires write to PCI_MSIX_ENTRY_DATA before any MSIX reads */
+ PCI_DEV_FLAGS_MSIX_TOUCH_ENTRY_DATA_FIRST = (__force pci_dev_flags_t) (1 << 13),
};
enum pci_irq_reroute_variant {
--
2.45.2
