[PATCH] PCI: MSI: Restore read_msi_msg_desc(); add get_cached_msi_msg_desc()
From: Ben Hutchings <hidden>
Date: 2010-07-23 13:56:35
Also in:
lkml
Subsystem:
pci subsystem, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Bjorn Helgaas, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
commit 2ca1af9aa3285c6a5f103ed31ad09f7399fc65d7 "PCI: MSI: Remove
unsafe and unnecessary hardware access" changed read_msi_msg_desc() to
return the last MSI message written instead of reading it from the
device, since it may be called while the device is in a reduced
power state.
However, the pSeries platform code really does need to read messages
from the device, since they are initially written by firmware.
Therefore:
- Restore the previous behaviour of read_msi_msg_desc()
- Add new functions get_cached_msi_msg{,_desc}() which return the
last MSI message written
- Use the new functions where appropriate
Signed-off-by: Ben Hutchings <redacted>
---
Compile-tested only.
Ben.
arch/ia64/kernel/msi_ia64.c | 2 +-
arch/ia64/sn/kernel/msi_sn.c | 2 +-
arch/x86/kernel/apic/io_apic.c | 2 +-
drivers/pci/msi.c | 47 +++++++++++++++++++++++++++++++++++----
include/linux/msi.h | 2 +
5 files changed, 47 insertions(+), 8 deletions(-)
diff --git a/arch/ia64/kernel/msi_ia64.c b/arch/ia64/kernel/msi_ia64.c
index 6c89228..4a746ea 100644
--- a/arch/ia64/kernel/msi_ia64.c
+++ b/arch/ia64/kernel/msi_ia64.c@@ -25,7 +25,7 @@ static int ia64_set_msi_irq_affinity(unsigned int irq, if (irq_prepare_move(irq, cpu)) return -1; - read_msi_msg(irq, &msg); + get_cached_msi_msg(irq, &msg); addr = msg.address_lo; addr &= MSI_ADDR_DEST_ID_MASK;
diff --git a/arch/ia64/sn/kernel/msi_sn.c b/arch/ia64/sn/kernel/msi_sn.c
index ebfdd6a..0c72dd4 100644
--- a/arch/ia64/sn/kernel/msi_sn.c
+++ b/arch/ia64/sn/kernel/msi_sn.c@@ -175,7 +175,7 @@ static int sn_set_msi_irq_affinity(unsigned int irq, * Release XIO resources for the old MSI PCI address */ - read_msi_msg(irq, &msg); + get_cached_msi_msg(irq, &msg); sn_pdev = (struct pcidev_info *)sn_irq_info->irq_pciioinfo; pdev = sn_pdev->pdi_linux_pcidev; provider = SN_PCIDEV_BUSPROVIDER(pdev);
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index e41ed24..4dc0084 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c@@ -3397,7 +3397,7 @@ static int set_msi_irq_affinity(unsigned int irq, const struct cpumask *mask) cfg = desc->chip_data; - read_msi_msg_desc(desc, &msg); + get_cached_msi_msg_desc(desc, &msg); msg.data &= ~MSI_DATA_VECTOR_MASK; msg.data |= MSI_DATA_VECTOR(cfg->vector);
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 4c14f31..69b7be3 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c@@ -197,9 +197,46 @@ void read_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg) { struct msi_desc *entry = get_irq_desc_msi(desc); - /* We do not touch the hardware (which may not even be - * accessible at the moment) but return the last message - * written. Assert that this is valid, assuming that + BUG_ON(entry->dev->current_state != PCI_D0); + + 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 get_cached_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg) +{ + struct msi_desc *entry = get_irq_desc_msi(desc); + + /* Assert that the cache is valid, assuming that * valid messages are not all-zeroes. */ BUG_ON(!(entry->msg.address_hi | entry->msg.address_lo | entry->msg.data));
@@ -207,11 +244,11 @@ void read_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg) *msg = entry->msg; } -void read_msi_msg(unsigned int irq, struct msi_msg *msg) +void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg) { struct irq_desc *desc = irq_to_desc(irq); - read_msi_msg_desc(desc, msg); + get_cached_msi_msg_desc(desc, msg); } void write_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg)
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 6991ab5..91b05c1 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h@@ -14,8 +14,10 @@ struct irq_desc; extern void mask_msi_irq(unsigned int irq); extern void unmask_msi_irq(unsigned int irq); extern void read_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg); +extern void get_cached_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg); extern void write_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg); extern void read_msi_msg(unsigned int irq, struct msi_msg *msg); +extern void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg); extern void write_msi_msg(unsigned int irq, struct msi_msg *msg); struct msi_desc {
--
1.6.2.5
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.