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Commit d7cc609f authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Jon Mason
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PCI/MSI: Support allocating virtual MSI interrupts 



For NTB devices, we want to be able to trigger MSI interrupts
through a memory window. In these cases we may want to use
more interrupts than the NTB PCI device has available in its MSI-X
table.

We allow for this by creating a new 'virtual' interrupt. These
interrupts are allocated as usual but are not programmed into the
MSI-X table (as there may not be space for them).

The MSI address and data will then handled through an NTB MSI library
introduced later in this series.

Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: default avatarJon Mason <jdmason@kudzu.us>
parent a944ccc3

drivers/pci/msi.c

+45 −9
Original line number Diff line number Diff line
@@ -192,6 +192,9 @@ static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag) 


static void __iomem *pci_msix_desc_addr(struct msi_desc *desc)

{

	if (desc->msi_attrib.is_virtual)

		return NULL;



	return desc->mask_base +

		desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;

}
@@ -206,14 +209,19 @@ static void __iomem *pci_msix_desc_addr(struct msi_desc *desc) 
u32 __pci_msix_desc_mask_irq(struct msi_desc *desc, u32 flag)

{

	u32 mask_bits = desc->masked;

	void __iomem *desc_addr;



	if (pci_msi_ignore_mask)

		return 0;

	desc_addr = pci_msix_desc_addr(desc);

	if (!desc_addr)

		return 0;



	mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;

	if (flag)

		mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT;

	writel(mask_bits, pci_msix_desc_addr(desc) + PCI_MSIX_ENTRY_VECTOR_CTRL);



	writel(mask_bits, desc_addr + PCI_MSIX_ENTRY_VECTOR_CTRL);



	return mask_bits;

}
@@ -273,6 +281,11 @@ void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg) 
	if (entry->msi_attrib.is_msix) {

		void __iomem *base = pci_msix_desc_addr(entry);



		if (!base) {

			WARN_ON(1);

			return;

		}



		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);
@@ -303,6 +316,9 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg) 
	} else if (entry->msi_attrib.is_msix) {

		void __iomem *base = pci_msix_desc_addr(entry);



		if (!base)

			goto skip;



		writel(msg->address_lo, base + PCI_MSIX_ENTRY_LOWER_ADDR);

		writel(msg->address_hi, base + PCI_MSIX_ENTRY_UPPER_ADDR);

		writel(msg->data, base + PCI_MSIX_ENTRY_DATA);
@@ -327,7 +343,13 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg) 
					      msg->data);

		}

	}



skip:

	entry->msg = *msg;



	if (entry->write_msi_msg)

		entry->write_msi_msg(entry, entry->write_msi_msg_data);



}



void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg)
@@ -550,6 +572,7 @@ msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd) 


	entry->msi_attrib.is_msix	= 0;

	entry->msi_attrib.is_64		= !!(control & PCI_MSI_FLAGS_64BIT);

	entry->msi_attrib.is_virtual    = 0;

	entry->msi_attrib.entry_nr	= 0;

	entry->msi_attrib.maskbit	= !!(control & PCI_MSI_FLAGS_MASKBIT);

	entry->msi_attrib.default_irq	= dev->irq;	/* Save IOAPIC IRQ */
@@ -674,6 +697,7 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base, 
	struct irq_affinity_desc *curmsk, *masks = NULL;

	struct msi_desc *entry;

	int ret, i;

	int vec_count = pci_msix_vec_count(dev);



	if (affd)

		masks = irq_create_affinity_masks(nvec, affd);
@@ -696,6 +720,10 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base, 
			entry->msi_attrib.entry_nr = entries[i].entry;

		else

			entry->msi_attrib.entry_nr = i;



		entry->msi_attrib.is_virtual =

			entry->msi_attrib.entry_nr >= vec_count;



		entry->msi_attrib.default_irq	= dev->irq;

		entry->mask_base		= base;
@@ -714,12 +742,19 @@ static void msix_program_entries(struct pci_dev *dev, 
{

	struct msi_desc *entry;

	int i = 0;

	void __iomem *desc_addr;



	for_each_pci_msi_entry(entry, dev) {

		if (entries)

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

		entry->masked = readl(pci_msix_desc_addr(entry) +



		desc_addr = pci_msix_desc_addr(entry);

		if (desc_addr)

			entry->masked = readl(desc_addr +

					      PCI_MSIX_ENTRY_VECTOR_CTRL);

		else

			entry->masked = 0;



		msix_mask_irq(entry, 1);

	}

}
@@ -932,7 +967,7 @@ int pci_msix_vec_count(struct pci_dev *dev) 
EXPORT_SYMBOL(pci_msix_vec_count);



static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,

			     int nvec, struct irq_affinity *affd)

			     int nvec, struct irq_affinity *affd, int flags)

{

	int nr_entries;

	int i, j;
@@ -943,7 +978,7 @@ static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, 
	nr_entries = pci_msix_vec_count(dev);

	if (nr_entries < 0)

		return nr_entries;

	if (nvec > nr_entries)

	if (nvec > nr_entries && !(flags & PCI_IRQ_VIRTUAL))

		return nr_entries;



	if (entries) {
@@ -1079,7 +1114,8 @@ EXPORT_SYMBOL(pci_enable_msi); 


static int __pci_enable_msix_range(struct pci_dev *dev,

				   struct msix_entry *entries, int minvec,

				   int maxvec, struct irq_affinity *affd)

				   int maxvec, struct irq_affinity *affd,

				   int flags)

{

	int rc, nvec = maxvec;
@@ -1096,7 +1132,7 @@ static int __pci_enable_msix_range(struct pci_dev *dev, 
				return -ENOSPC;

		}



		rc = __pci_enable_msix(dev, entries, nvec, affd);

		rc = __pci_enable_msix(dev, entries, nvec, affd, flags);

		if (rc == 0)

			return nvec;
@@ -1127,7 +1163,7 @@ static int __pci_enable_msix_range(struct pci_dev *dev, 
int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,

		int minvec, int maxvec)

{

	return __pci_enable_msix_range(dev, entries, minvec, maxvec, NULL);

	return __pci_enable_msix_range(dev, entries, minvec, maxvec, NULL, 0);

}

EXPORT_SYMBOL(pci_enable_msix_range);
@@ -1167,7 +1203,7 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs, 


	if (flags & PCI_IRQ_MSIX) {

		msix_vecs = __pci_enable_msix_range(dev, NULL, min_vecs,

						    max_vecs, affd);

						    max_vecs, affd, flags);

		if (msix_vecs > 0)

			return msix_vecs;

	}

include/linux/msi.h

+8 −0
Original line number Diff line number Diff line
@@ -64,6 +64,10 @@ struct ti_sci_inta_msi_desc { 
 * @msg:	The last set MSI message cached for reuse

 * @affinity:	Optional pointer to a cpu affinity mask for this descriptor

 *

 * @write_msi_msg:	Callback that may be called when the MSI message

 *			address or data changes

 * @write_msi_msg_data:	Data parameter for the callback.

 *

 * @masked:	[PCI MSI/X] Mask bits

 * @is_msix:	[PCI MSI/X] True if MSI-X

 * @multiple:	[PCI MSI/X] log2 num of messages allocated
@@ -90,6 +94,9 @@ struct msi_desc { 
	const void			*iommu_cookie;

#endif



	void (*write_msi_msg)(struct msi_desc *entry, void *data);

	void *write_msi_msg_data;



	union {

		/* PCI MSI/X specific data */

		struct {
@@ -100,6 +107,7 @@ struct msi_desc { 
				u8	multi_cap	: 3;

				u8	maskbit		: 1;

				u8	is_64		: 1;

				u8	is_virtual	: 1;

				u16	entry_nr;

				unsigned default_irq;

			} msi_attrib;

include/linux/pci.h

+9 −0
Original line number Diff line number Diff line
@@ -1362,6 +1362,15 @@ int pci_set_vga_state(struct pci_dev *pdev, bool decode, 
#define PCI_IRQ_MSI		(1 << 1) /* Allow MSI interrupts */

#define PCI_IRQ_MSIX		(1 << 2) /* Allow MSI-X interrupts */

#define PCI_IRQ_AFFINITY	(1 << 3) /* Auto-assign affinity */



/*

 * Virtual interrupts allow for more interrupts to be allocated

 * than the device has interrupts for. These are not programmed

 * into the device's MSI-X table and must be handled by some

 * other driver means.

 */

#define PCI_IRQ_VIRTUAL		(1 << 4)



#define PCI_IRQ_ALL_TYPES \

	(PCI_IRQ_LEGACY | PCI_IRQ_MSI | PCI_IRQ_MSIX)