From 30da55242818a8ca08583188ebcbaccd283ad4d9 Mon Sep 17 00:00:00 2001

From: Ben Hutchings <bhutchings@solarflare.com>

Date: Fri, 23 Jul 2010 14:56:28 +0100

Subject: PCI: MSI: Restore read_msi_msg_desc(); add get_cached_msi_msg_desc()

From: Ben Hutchings <bhutchings@solarflare.com>

commit 30da55242818a8ca08583188ebcbaccd283ad4d9 upstream.

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>

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---

 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(-)

--- 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(uns

 	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;

--- a/arch/ia64/sn/kernel/msi_sn.c

+++ b/arch/ia64/sn/kernel/msi_sn.c

@@ -174,7 +174,7 @@ static int sn_set_msi_irq_affinity(unsig

 	 * 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);

--- a/arch/x86/kernel/apic/io_apic.c

+++ b/arch/x86/kernel/apic/io_apic.c

@@ -3338,7 +3338,7 @@ static int set_msi_irq_affinity(unsigned

 	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);

--- a/drivers/pci/msi.c

+++ b/drivers/pci/msi.c

@@ -196,9 +196,46 @@ void read_msi_msg_desc(struct irq_desc *

 {

 	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));

@@ -206,11 +243,11 @@ void read_msi_msg_desc(struct irq_desc *

 	*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)

--- 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 {