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Commit 30da5524 authored by Ben Hutchings's avatar Ben Hutchings Committed by Jesse Barnes
Browse files

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: default avatarMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 911e1c9b

arch/ia64/kernel/msi_ia64.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

arch/ia64/sn/kernel/msi_sn.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/x86/kernel/apic/io_apic.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/pci/msi.c

+42 −5
Original line number Diff line number Diff line
@@ -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)

include/linux/msi.h

+2 −0
Original line number Diff line number Diff line
@@ -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 {