Commit 9c831334 authored by Michael Ellerman's avatar Michael Ellerman Committed by Greg Kroah-Hartman
Browse files

MSI: Give archs the option to allocate all MSI/Xs at once. 



This patch introduces an optional function, arch_setup_msi_irqs(),
(note the plural) which gives an arch the opportunity to do per-device
setup for MSI/X and then allocate all the requested MSI/Xs at once.

If that's not required by the arch, the default version simply calls
arch_setup_msi_irq() for each MSI irq required.

arch_setup_msi_irqs() is passed a pdev, attached to the pdev is a list
of msi_descs with irq == 0, it is up to the arch to connect these up to
an irq (via set_irq_msi()) or return an error. For convenience the number
of vectors and the type are passed also.

All msi_descs with irq != 0 are considered allocated, and the arch
teardown routine will be called on them when necessary.

The existing semantics of pci_enable_msix() are that if the requested
number of irqs can not be allocated, the maximum number that _could_ be
allocated is returned. To support that, we define that in case of an
error from arch_setup_msi_irqs(), the number of msi_descs with irq != 0
are considered allocated, and are counted toward the "max that could be
allocated".


Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 7fe3730d

drivers/pci/msi.c

+44 −19
Original line number Diff line number Diff line
@@ -334,13 +334,15 @@ static int msi_capability_init(struct pci_dev *dev) 
			msi_mask_bits_reg(pos, is_64bit_address(control)),

			maskbits);

	}

	list_add(&entry->list, &dev->msi_list);



	/* Configure MSI capability structure */

	ret = arch_setup_msi_irq(dev, entry);

	ret = arch_setup_msi_irqs(dev, 1, PCI_CAP_ID_MSI);

	if (ret) {

		list_del(&entry->list);

		kfree(entry);

		return ret;

	}

	list_add(&entry->list, &dev->msi_list);



	/* Set MSI enabled bits	 */

	pci_intx(dev, 0);		/* disable intx */
@@ -365,7 +367,7 @@ static int msix_capability_init(struct pci_dev *dev, 
				struct msix_entry *entries, int nvec)

{

	struct msi_desc *entry;

	int irq, pos, i, j, nr_entries, ret;

	int pos, i, j, nr_entries, ret;

	unsigned long phys_addr;

	u32 table_offset;

 	u16 control;
@@ -404,30 +406,33 @@ static int msix_capability_init(struct pci_dev *dev, 
		entry->dev = dev;

		entry->mask_base = base;



		/* Configure MSI-X capability structure */

		ret = arch_setup_msi_irq(dev, entry);

		if (ret) {

			kfree(entry);

			break;

		}

 		entries[i].vector = entry->irq;

		list_add(&entry->list, &dev->msi_list);

	}

	if (i != nvec) {

		int avail = i - 1;

		i--;

		for (; i >= 0; i--) {

			irq = (entries + i)->vector;

			msi_free_irq(dev, irq);

			(entries + i)->vector = 0;



	ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);

	if (ret) {

		int avail = 0;

		list_for_each_entry(entry, &dev->msi_list, list) {

			if (entry->irq != 0) {

				avail++;

				msi_free_irq(dev, entry->irq);

			}

		}



		/* If we had some success report the number of irqs

		 * we succeeded in setting up.

		 */

		if (avail <= 0)

			avail = -EBUSY;

		if (avail == 0)

			avail = ret;

		return avail;

	}



	i = 0;

	list_for_each_entry(entry, &dev->msi_list, list) {

		entries[i].vector = entry->irq;

		set_irq_msi(entry->irq, entry);

		i++;

	}

	/* Set MSI-X enabled bits */

	pci_intx(dev, 0);		/* disable intx */

	msix_set_enable(dev, 1);
@@ -694,3 +699,23 @@ arch_msi_check_device(struct pci_dev* dev, int nvec, int type) 
	return 0;

}



int __attribute__ ((weak))

arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *entry)

{

	return 0;

}



int __attribute__ ((weak))

arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)

{

	struct msi_desc *entry;

	int ret;



	list_for_each_entry(entry, &dev->msi_list, list) {

		ret = arch_setup_msi_irq(dev, entry);

		if (ret)

			return ret;

	}



	return 0;

}

include/linux/msi.h

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ struct msi_desc { 
 */

int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc);

void arch_teardown_msi_irq(unsigned int irq);

extern int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);

extern int arch_msi_check_device(struct pci_dev* dev, int nvec, int type);

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