Commit f2440d9a authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Jesse Barnes
Browse files

PCI MSI: Refactor interrupt masking code 



Since most of the callers already know whether they have an MSI or
an MSI-X capability, split msi_set_mask_bits() into msi_mask_irq()
and msix_mask_irq().  The only callers which don't (mask_msi_irq()
and unmask_msi_irq()) can share code in msi_set_mask_bit().  This then
becomes the only caller of msix_flush_writes(), so we can inline it.
The flushing read can be to any address that belongs to the device,
so we can eliminate the calculation too.

We can also get rid of maskbits_mask from struct msi_desc and simply
recalculate it on the rare occasion that we need it.  The single-bit
'masked' element is replaced by a copy of the 32-bit 'masked' register,
so this patch does not affect the size of msi_desc.

Signed-off-by: default avatarMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 264d9caa

drivers/pci/msi.c

+75 −80
Original line number Diff line number Diff line
@@ -105,17 +105,14 @@ static inline __attribute_const__ u32 msi_mask(unsigned x) 
	return (1 << (1 << x)) - 1;

}



static void msix_flush_writes(struct irq_desc *desc)

static inline __attribute_const__ u32 msi_capable_mask(u16 control)

{

	struct msi_desc *entry;



	entry = get_irq_desc_msi(desc);

	BUG_ON(!entry);

	if (entry->msi_attrib.is_msix) {

		int offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +

			PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;

		readl(entry->mask_base + offset);

	return msi_mask((control >> 1) & 7);

}



static inline __attribute_const__ u32 msi_enabled_mask(u16 control)

{

	return msi_mask((control >> 4) & 7);

}



/*
@@ -127,32 +124,57 @@ static void msix_flush_writes(struct irq_desc *desc) 
 * Returns 1 if it succeeded in masking the interrupt and 0 if the device

 * doesn't support MSI masking.

 */

static int msi_set_mask_bits(struct irq_desc *desc, u32 mask, u32 flag)

static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)

{

	struct msi_desc *entry;

	u32 mask_bits = desc->masked;



	entry = get_irq_desc_msi(desc);

	BUG_ON(!entry);

	if (entry->msi_attrib.is_msix) {

		int offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +

	if (!desc->msi_attrib.maskbit)

		return;



	mask_bits &= ~mask;

	mask_bits |= flag;

	pci_write_config_dword(desc->dev, desc->mask_pos, mask_bits);

	desc->masked = mask_bits;

}



/*

 * This internal function does not flush PCI writes to the device.

 * All users must ensure that they read from the device before either

 * assuming that the device state is up to date, or returning out of this

 * file.  This saves a few milliseconds when initialising devices with lots

 * of MSI-X interrupts.

 */

static void msix_mask_irq(struct msi_desc *desc, u32 flag)

{

	u32 mask_bits = desc->masked;

	unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +

					PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;

		writel(flag, entry->mask_base + offset);

		readl(entry->mask_base + offset);

	} else {

		int pos;

		u32 mask_bits;

	mask_bits &= ~1;

	mask_bits |= flag;

	writel(mask_bits, desc->mask_base + offset);

	desc->masked = mask_bits;

}



		if (!entry->msi_attrib.maskbit)

			return 0;

static void msi_set_mask_bit(unsigned irq, u32 flag)

{

	struct msi_desc *desc = get_irq_msi(irq);



		pos = entry->mask_pos;

		pci_read_config_dword(entry->dev, pos, &mask_bits);

		mask_bits &= ~mask;

		mask_bits |= flag & mask;

		pci_write_config_dword(entry->dev, pos, mask_bits);

	if (desc->msi_attrib.is_msix) {

		msix_mask_irq(desc, flag);

		readl(desc->mask_base);		/* Flush write to device */

	} else {

		msi_mask_irq(desc, 1, flag);

	}

	entry->msi_attrib.masked = !!flag;

	return 1;

}



void mask_msi_irq(unsigned int irq)

{

	msi_set_mask_bit(irq, 1);

}



void unmask_msi_irq(unsigned int irq)

{

	msi_set_mask_bit(irq, 0);

}



void read_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg)
@@ -230,22 +252,6 @@ void write_msi_msg(unsigned int irq, struct msi_msg *msg) 
	write_msi_msg_desc(desc, msg);

}



void mask_msi_irq(unsigned int irq)

{

	struct irq_desc *desc = irq_to_desc(irq);



	msi_set_mask_bits(desc, 1, 1);

	msix_flush_writes(desc);

}



void unmask_msi_irq(unsigned int irq)

{

	struct irq_desc *desc = irq_to_desc(irq);



	msi_set_mask_bits(desc, 1, 0);

	msix_flush_writes(desc);

}



static int msi_free_irqs(struct pci_dev* dev);



static struct msi_desc *alloc_msi_entry(struct pci_dev *dev)
@@ -281,13 +287,9 @@ static void __pci_restore_msi_state(struct pci_dev *dev) 
	pci_intx_for_msi(dev, 0);

	msi_set_enable(dev, 0);

	write_msi_msg(dev->irq, &entry->msg);

	if (entry->msi_attrib.maskbit) {

		struct irq_desc *desc = irq_to_desc(dev->irq);

		msi_set_mask_bits(desc, entry->msi_attrib.maskbits_mask,

				  entry->msi_attrib.masked);

	}



	pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);

	msi_mask_irq(entry, msi_capable_mask(control), entry->masked);

	control &= ~PCI_MSI_FLAGS_QSIZE;

	control |= PCI_MSI_FLAGS_ENABLE;

	pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
@@ -307,9 +309,8 @@ static void __pci_restore_msix_state(struct pci_dev *dev) 
	msix_set_enable(dev, 0);



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

		struct irq_desc *desc = irq_to_desc(entry->irq);

		write_msi_msg(entry->irq, &entry->msg);

		msi_set_mask_bits(desc, 1, entry->msi_attrib.masked);

		msix_mask_irq(entry, entry->masked);

	}



	BUG_ON(list_empty(&dev->msi_list));
@@ -342,6 +343,7 @@ static int msi_capability_init(struct pci_dev *dev) 
	struct msi_desc *entry;

	int pos, ret;

	u16 control;

	unsigned mask;



	msi_set_enable(dev, 0);	/* Ensure msi is disabled as I set it up */
@@ -356,21 +358,16 @@ static int msi_capability_init(struct pci_dev *dev) 
	entry->msi_attrib.is_64 = is_64bit_address(control);

	entry->msi_attrib.entry_nr = 0;

	entry->msi_attrib.maskbit = is_mask_bit_support(control);

	entry->msi_attrib.masked = 1;

	entry->msi_attrib.default_irq = dev->irq;	/* Save IOAPIC IRQ */

	entry->msi_attrib.pos = pos;

	if (entry->msi_attrib.maskbit) {

		unsigned int base, maskbits, temp;



		base = msi_mask_bits_reg(pos, entry->msi_attrib.is_64);

		entry->mask_pos = base;

	entry->mask_pos = msi_mask_bits_reg(pos, entry->msi_attrib.is_64);

	/* All MSIs are unmasked by default, Mask them all */

		pci_read_config_dword(dev, base, &maskbits);

		temp = msi_mask((control & PCI_MSI_FLAGS_QMASK) >> 1);

		maskbits |= temp;

		pci_write_config_dword(dev, base, maskbits);

		entry->msi_attrib.maskbits_mask = temp;

	}

	if (entry->msi_attrib.maskbit)

		pci_read_config_dword(dev, entry->mask_pos, &entry->masked);

	mask = msi_capable_mask(control);

	msi_mask_irq(entry, mask, mask);



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



	/* Configure MSI capability structure */
@@ -435,11 +432,12 @@ static int msix_capability_init(struct pci_dev *dev, 
		entry->msi_attrib.is_msix = 1;

		entry->msi_attrib.is_64 = 1;

		entry->msi_attrib.entry_nr = j;

		entry->msi_attrib.maskbit = 1;

		entry->msi_attrib.masked = 1;

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

		entry->msi_attrib.pos = pos;

		entry->mask_base = base;

		entry->masked = readl(base + j * PCI_MSIX_ENTRY_SIZE +

					PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);

		msix_mask_irq(entry, 1);



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

	}
@@ -558,7 +556,9 @@ EXPORT_SYMBOL(pci_enable_msi); 


void pci_msi_shutdown(struct pci_dev *dev)

{

	struct msi_desc *entry;

	struct msi_desc *desc;

	u32 mask;

	u16 ctrl;



	if (!pci_msi_enable || !dev || !dev->msi_enabled)

		return;
@@ -568,18 +568,13 @@ void pci_msi_shutdown(struct pci_dev* dev) 
	dev->msi_enabled = 0;



	BUG_ON(list_empty(&dev->msi_list));

	entry = list_entry(dev->msi_list.next, struct msi_desc, list);

	/* Return the the pci reset with msi irqs unmasked */

	if (entry->msi_attrib.maskbit) {

		u32 mask = entry->msi_attrib.maskbits_mask;

		struct irq_desc *desc = irq_to_desc(dev->irq);

		msi_set_mask_bits(desc, mask, ~mask);

	}

	if (entry->msi_attrib.is_msix)

		return;

	desc = list_first_entry(&dev->msi_list, struct msi_desc, list);

	pci_read_config_word(dev, desc->msi_attrib.pos + PCI_MSI_FLAGS, &ctrl);

	mask = msi_capable_mask(ctrl);

	msi_mask_irq(desc, mask, ~mask);



	/* Restore dev->irq to its default pin-assertion irq */

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

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

}



void pci_disable_msi(struct pci_dev* dev)

include/linux/msi.h

+2 −3
Original line number Diff line number Diff line
@@ -22,14 +22,13 @@ struct msi_desc { 
	struct {

		__u8	is_msix	: 1;

		__u8	maskbit	: 1; 	/* mask-pending bit supported ?   */

		__u8	masked	: 1;

		__u8	is_64	: 1;	/* Address size: 0=32bit 1=64bit  */

		__u8	pos;	 	/* Location of the msi capability */

		__u16	entry_nr;    	/* specific enabled entry 	  */

		__u32	maskbits_mask;  /* mask bits mask */

		unsigned default_irq;	/* default pre-assigned irq	  */

	} msi_attrib;



	u32 masked;			/* mask bits */

	unsigned int irq;

	struct list_head list;

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