PCI: MSI: Restore read_msi_msg_desc(); add get_cached_msi_msg_desc()
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
Acked-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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
@@ -197,14 +197,32 @@
{
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
- * valid messages are not all-zeroes. */
- BUG_ON(!(entry->msg.address_hi | entry->msg.address_lo |
- entry->msg.data));
+ BUG_ON(entry->dev->current_state != PCI_D0);
- *msg = entry->msg;
+ 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)
@@ -214,6 +232,25 @@
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));
+
+ *msg = entry->msg;
+}
+
+void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ get_cached_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);