Merge branch 'pci/msi' into next (04f982be) · Commits · e / devices / android_kernel_fairphone_FP4

Documentation/PCI/MSI-HOWTO.txt

+210 −98

Original line number	Original line	Diff line number	Diff line
	@@ -82,93 +82,111 @@ Most of the hard work is done for the driver in the PCI layer. It simply
	has to request that the PCI layer set up the MSI capability for this		has to request that the PCI layer set up the MSI capability for this
	device.		device.

	4.2.1 pci_enable_msi		4.2.1 pci_enable_msi_range

	int pci_enable_msi(struct pci_dev *dev)		int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec)

	A successful call allocates ONE interrupt to the device, regardless		This function allows a device driver to request any number of MSI
	of how many MSIs the device supports. The device is switched from		interrupts within specified range from 'minvec' to 'maxvec'.
	pin-based interrupt mode to MSI mode. The dev->irq number is changed
	to a new number which represents the message signaled interrupt;
	consequently, this function should be called before the driver calls
	request_irq(), because an MSI is delivered via a vector that is
	different from the vector of a pin-based interrupt.

	4.2.2 pci_enable_msi_block		If this function returns a positive number it indicates the number of
			MSI interrupts that have been successfully allocated. In this case
			the device is switched from pin-based interrupt mode to MSI mode and
			updates dev->irq to be the lowest of the new interrupts assigned to it.
			The other interrupts assigned to the device are in the range dev->irq
			to dev->irq + returned value - 1. Device driver can use the returned
			number of successfully allocated MSI interrupts to further allocate
			and initialize device resources.

	int pci_enable_msi_block(struct pci_dev *dev, int count)		If this function returns a negative number, it indicates an error and
			the driver should not attempt to request any more MSI interrupts for
			this device.

	This variation on the above call allows a device driver to request multiple		This function should be called before the driver calls request_irq(),
	MSIs. The MSI specification only allows interrupts to be allocated in		because MSI interrupts are delivered via vectors that are different
	powers of two, up to a maximum of 2^5 (32).		from the vector of a pin-based interrupt.

	If this function returns 0, it has succeeded in allocating at least as many		It is ideal if drivers can cope with a variable number of MSI interrupts;
	interrupts as the driver requested (it may have allocated more in order		there are many reasons why the platform may not be able to provide the
	to satisfy the power-of-two requirement). In this case, the function		exact number that a driver asks for.
	enables MSI on this device and updates dev->irq to be the lowest of
	the new interrupts assigned to it. The other interrupts assigned to
	the device are in the range dev->irq to dev->irq + count - 1.

	If this function returns a negative number, it indicates an error and		There could be devices that can not operate with just any number of MSI
	the driver should not attempt to request any more MSI interrupts for		interrupts within a range. See chapter 4.3.1.3 to get the idea how to
	this device. If this function returns a positive number, it is		handle such devices for MSI-X - the same logic applies to MSI.
	less than 'count' and indicates the number of interrupts that could have
	been allocated. In neither case is the irq value updated or the device
	switched into MSI mode.

	The device driver must decide what action to take if
	pci_enable_msi_block() returns a value less than the number requested.
	For instance, the driver could still make use of fewer interrupts;
	in this case the driver should call pci_enable_msi_block()
	again. Note that it is not guaranteed to succeed, even when the
	'count' has been reduced to the value returned from a previous call to
	pci_enable_msi_block(). This is because there are multiple constraints
	on the number of vectors that can be allocated; pci_enable_msi_block()
	returns as soon as it finds any constraint that doesn't allow the
	call to succeed.

	4.2.3 pci_enable_msi_block_auto

	int pci_enable_msi_block_auto(struct pci_dev dev, int count)

	This variation on pci_enable_msi() call allows a device driver to request
	the maximum possible number of MSIs. The MSI specification only allows
	interrupts to be allocated in powers of two, up to a maximum of 2^5 (32).

	If this function returns a positive number, it indicates that it has
	succeeded and the returned value is the number of allocated interrupts. In
	this case, the function enables MSI on this device and updates dev->irq to
	be the lowest of the new interrupts assigned to it. The other interrupts
	assigned to the device are in the range dev->irq to dev->irq + returned
	value - 1.

	If this function returns a negative number, it indicates an error and		4.2.1.1 Maximum possible number of MSI interrupts
	the driver should not attempt to request any more MSI interrupts for
	this device.		The typical usage of MSI interrupts is to allocate as many vectors as
			possible, likely up to the limit returned by pci_msi_vec_count() function:

			static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec)
			{
			return pci_enable_msi_range(pdev, 1, nvec);
			}

			Note the value of 'minvec' parameter is 1. As 'minvec' is inclusive,
			the value of 0 would be meaningless and could result in error.

	If the device driver needs to know the number of interrupts the device		Some devices have a minimal limit on number of MSI interrupts.
	supports it can pass the pointer count where that number is stored. The		In this case the function could look like this:
	device driver must decide what action to take if pci_enable_msi_block_auto()
	succeeds, but returns a value less than the number of interrupts supported.
	If the device driver does not need to know the number of interrupts
	supported, it can set the pointer count to NULL.

	4.2.4 pci_disable_msi		static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec)
			{
			return pci_enable_msi_range(pdev, FOO_DRIVER_MINIMUM_NVEC, nvec);
			}

			4.2.1.2 Exact number of MSI interrupts

			If a driver is unable or unwilling to deal with a variable number of MSI
			interrupts it could request a particular number of interrupts by passing
			that number to pci_enable_msi_range() function as both 'minvec' and 'maxvec'
			parameters:

			static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec)
			{
			return pci_enable_msi_range(pdev, nvec, nvec);
			}

			4.2.1.3 Single MSI mode

			The most notorious example of the request type described above is
			enabling the single MSI mode for a device. It could be done by passing
			two 1s as 'minvec' and 'maxvec':

			static int foo_driver_enable_single_msi(struct pci_dev *pdev)
			{
			return pci_enable_msi_range(pdev, 1, 1);
			}

			4.2.2 pci_disable_msi

	void pci_disable_msi(struct pci_dev *dev)		void pci_disable_msi(struct pci_dev *dev)

	This function should be used to undo the effect of pci_enable_msi() or		This function should be used to undo the effect of pci_enable_msi_range().
	pci_enable_msi_block() or pci_enable_msi_block_auto(). Calling it restores		Calling it restores dev->irq to the pin-based interrupt number and frees
	dev->irq to the pin-based interrupt number and frees the previously		the previously allocated MSIs. The interrupts may subsequently be assigned
	allocated message signaled interrupt(s). The interrupt may subsequently be		to another device, so drivers should not cache the value of dev->irq.
	assigned to another device, so drivers should not cache the value of
	dev->irq.

	Before calling this function, a device driver must always call free_irq()		Before calling this function, a device driver must always call free_irq()
	on any interrupt for which it previously called request_irq().		on any interrupt for which it previously called request_irq().
	Failure to do so results in a BUG_ON(), leaving the device with		Failure to do so results in a BUG_ON(), leaving the device with
	MSI enabled and thus leaking its vector.		MSI enabled and thus leaking its vector.

			4.2.3 pci_msi_vec_count

			int pci_msi_vec_count(struct pci_dev *dev)

			This function could be used to retrieve the number of MSI vectors the
			device requested (via the Multiple Message Capable register). The MSI
			specification only allows the returned value to be a power of two,
			up to a maximum of 2^5 (32).

			If this function returns a negative number, it indicates the device is
			not capable of sending MSIs.

			If this function returns a positive number, it indicates the maximum
			number of MSI interrupt vectors that could be allocated.

	4.3 Using MSI-X		4.3 Using MSI-X

	The MSI-X capability is much more flexible than the MSI capability.		The MSI-X capability is much more flexible than the MSI capability.
	@@ -188,26 +206,31 @@ in each element of the array to indicate for which entries the kernel
	should assign interrupts; it is invalid to fill in two entries with the		should assign interrupts; it is invalid to fill in two entries with the
	same number.		same number.

	4.3.1 pci_enable_msix		4.3.1 pci_enable_msix_range

	int pci_enable_msix(struct pci_dev dev, struct msix_entry entries, int nvec)		int pci_enable_msix_range(struct pci_dev dev, struct msix_entry entries,
			int minvec, int maxvec)

	Calling this function asks the PCI subsystem to allocate 'nvec' MSIs.		Calling this function asks the PCI subsystem to allocate any number of
			MSI-X interrupts within specified range from 'minvec' to 'maxvec'.
	The 'entries' argument is a pointer to an array of msix_entry structs		The 'entries' argument is a pointer to an array of msix_entry structs
	which should be at least 'nvec' entries in size. On success, the		which should be at least 'maxvec' entries in size.
	device is switched into MSI-X mode and the function returns 0.
	The 'vector' member in each entry is populated with the interrupt number;		On success, the device is switched into MSI-X mode and the function
			returns the number of MSI-X interrupts that have been successfully
			allocated. In this case the 'vector' member in entries numbered from
			0 to the returned value - 1 is populated with the interrupt number;
	the driver should then call request_irq() for each 'vector' that it		the driver should then call request_irq() for each 'vector' that it
	decides to use. The device driver is responsible for keeping track of the		decides to use. The device driver is responsible for keeping track of the
	interrupts assigned to the MSI-X vectors so it can free them again later.		interrupts assigned to the MSI-X vectors so it can free them again later.
			Device driver can use the returned number of successfully allocated MSI-X
			interrupts to further allocate and initialize device resources.

	If this function returns a negative number, it indicates an error and		If this function returns a negative number, it indicates an error and
	the driver should not attempt to allocate any more MSI-X interrupts for		the driver should not attempt to allocate any more MSI-X interrupts for
	this device. If it returns a positive number, it indicates the maximum		this device.
	number of interrupt vectors that could have been allocated. See example
	below.

	This function, in contrast with pci_enable_msi(), does not adjust		This function, in contrast with pci_enable_msi_range(), does not adjust
	dev->irq. The device will not generate interrupts for this interrupt		dev->irq. The device will not generate interrupts for this interrupt
	number once MSI-X is enabled.		number once MSI-X is enabled.

	@@ -218,28 +241,103 @@ It is ideal if drivers can cope with a variable number of MSI-X interrupts;
	there are many reasons why the platform may not be able to provide the		there are many reasons why the platform may not be able to provide the
	exact number that a driver asks for.		exact number that a driver asks for.

	A request loop to achieve that might look like:		There could be devices that can not operate with just any number of MSI-X
			interrupts within a range. E.g., an network adapter might need let's say
			four vectors per each queue it provides. Therefore, a number of MSI-X
			interrupts allocated should be a multiple of four. In this case interface
			pci_enable_msix_range() can not be used alone to request MSI-X interrupts
			(since it can allocate any number within the range, without any notion of
			the multiple of four) and the device driver should master a custom logic
			to request the required number of MSI-X interrupts.

			4.3.1.1 Maximum possible number of MSI-X interrupts

			The typical usage of MSI-X interrupts is to allocate as many vectors as
			possible, likely up to the limit returned by pci_msix_vec_count() function:

	static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)		static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
	{		{
	while (nvec >= FOO_DRIVER_MINIMUM_NVEC) {		return pci_enable_msi_range(adapter->pdev, adapter->msix_entries,
	rc = pci_enable_msix(adapter->pdev,		1, nvec);
	adapter->msix_entries, nvec);		}
	if (rc > 0)
	nvec = rc;		Note the value of 'minvec' parameter is 1. As 'minvec' is inclusive,
	else		the value of 0 would be meaningless and could result in error.
	return rc;
			Some devices have a minimal limit on number of MSI-X interrupts.
			In this case the function could look like this:

			static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
			{
			return pci_enable_msi_range(adapter->pdev, adapter->msix_entries,
			FOO_DRIVER_MINIMUM_NVEC, nvec);
			}

			4.3.1.2 Exact number of MSI-X interrupts

			If a driver is unable or unwilling to deal with a variable number of MSI-X
			interrupts it could request a particular number of interrupts by passing
			that number to pci_enable_msix_range() function as both 'minvec' and 'maxvec'
			parameters:

			static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
			{
			return pci_enable_msi_range(adapter->pdev, adapter->msix_entries,
			nvec, nvec);
	}		}

			4.3.1.3 Specific requirements to the number of MSI-X interrupts

			As noted above, there could be devices that can not operate with just any
			number of MSI-X interrupts within a range. E.g., let's assume a device that
			is only capable sending the number of MSI-X interrupts which is a power of
			two. A routine that enables MSI-X mode for such device might look like this:

			/*
			* Assume 'minvec' and 'maxvec' are non-zero
			*/
			static int foo_driver_enable_msix(struct foo_adapter *adapter,
			int minvec, int maxvec)
			{
			int rc;

			minvec = roundup_pow_of_two(minvec);
			maxvec = rounddown_pow_of_two(maxvec);

			if (minvec > maxvec)
			return -ERANGE;

			retry:
			rc = pci_enable_msix_range(adapter->pdev, adapter->msix_entries,
			maxvec, maxvec);
			/*
			* -ENOSPC is the only error code allowed to be analized
			*/
			if (rc == -ENOSPC) {
			if (maxvec == 1)
			return -ENOSPC;

			maxvec /= 2;

			if (minvec > maxvec)
	return -ENOSPC;		return -ENOSPC;

			goto retry;
			}

			return rc;
	}		}

			Note how pci_enable_msix_range() return value is analized for a fallback -
			any error code other than -ENOSPC indicates a fatal error and should not
			be retried.

	4.3.2 pci_disable_msix		4.3.2 pci_disable_msix

	void pci_disable_msix(struct pci_dev *dev)		void pci_disable_msix(struct pci_dev *dev)

	This function should be used to undo the effect of pci_enable_msix(). It frees		This function should be used to undo the effect of pci_enable_msix_range().
	the previously allocated message signaled interrupts. The interrupts may		It frees the previously allocated MSI-X interrupts. The interrupts may
	subsequently be assigned to another device, so drivers should not cache		subsequently be assigned to another device, so drivers should not cache
	the value of the 'vector' elements over a call to pci_disable_msix().		the value of the 'vector' elements over a call to pci_disable_msix().

	@@ -255,18 +353,32 @@ MSI-X Table. This address is mapped by the PCI subsystem, and should not
	be accessed directly by the device driver. If the driver wishes to		be accessed directly by the device driver. If the driver wishes to
	mask or unmask an interrupt, it should call disable_irq() / enable_irq().		mask or unmask an interrupt, it should call disable_irq() / enable_irq().

			4.3.4 pci_msix_vec_count

			int pci_msix_vec_count(struct pci_dev *dev)

			This function could be used to retrieve number of entries in the device
			MSI-X table.

			If this function returns a negative number, it indicates the device is
			not capable of sending MSI-Xs.

			If this function returns a positive number, it indicates the maximum
			number of MSI-X interrupt vectors that could be allocated.

	4.4 Handling devices implementing both MSI and MSI-X capabilities		4.4 Handling devices implementing both MSI and MSI-X capabilities

	If a device implements both MSI and MSI-X capabilities, it can		If a device implements both MSI and MSI-X capabilities, it can
	run in either MSI mode or MSI-X mode, but not both simultaneously.		run in either MSI mode or MSI-X mode, but not both simultaneously.
	This is a requirement of the PCI spec, and it is enforced by the		This is a requirement of the PCI spec, and it is enforced by the
	PCI layer. Calling pci_enable_msi() when MSI-X is already enabled or		PCI layer. Calling pci_enable_msi_range() when MSI-X is already
	pci_enable_msix() when MSI is already enabled results in an error.		enabled or pci_enable_msix_range() when MSI is already enabled
	If a device driver wishes to switch between MSI and MSI-X at runtime,		results in an error. If a device driver wishes to switch between MSI
	it must first quiesce the device, then switch it back to pin-interrupt		and MSI-X at runtime, it must first quiesce the device, then switch
	mode, before calling pci_enable_msi() or pci_enable_msix() and resuming		it back to pin-interrupt mode, before calling pci_enable_msi_range()
	operation. This is not expected to be a common operation but may be		or pci_enable_msix_range() and resuming operation. This is not expected
	useful for debugging or testing during development.		to be a common operation but may be useful for debugging or testing
			during development.

	4.5 Considerations when using MSIs		4.5 Considerations when using MSIs

	@@ -381,5 +493,5 @@ or disabled (0). If 0 is found in any of the msi_bus files belonging
	to bridges between the PCI root and the device, MSIs are disabled.		to bridges between the PCI root and the device, MSIs are disabled.

	It is also worth checking the device driver to see whether it supports MSIs.		It is also worth checking the device driver to see whether it supports MSIs.
	For example, it may contain calls to pci_enable_msi(), pci_enable_msix() or		For example, it may contain calls to pci_enable_msi_range() or
	pci_enable_msi_block().		pci_enable_msix_range().

drivers/ata/ahci.c

+35 −21

Original line number	Original line	Diff line number	Diff line
	@@ -1095,26 +1095,40 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
	{}		{}
	#endif		#endif

	int ahci_init_interrupts(struct pci_dev pdev, struct ahci_host_priv hpriv)		int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
			struct ahci_host_priv *hpriv)
	{		{
	int rc;		int rc, nvec;
	unsigned int maxvec;
			if (hpriv->flags & AHCI_HFLAG_NO_MSI)
			goto intx;

			rc = pci_msi_vec_count(pdev);
			if (rc < 0)
			goto intx;

	if (!(hpriv->flags & AHCI_HFLAG_NO_MSI)) {
	rc = pci_enable_msi_block_auto(pdev, &maxvec);
	if (rc > 0) {
	if ((rc == maxvec) \|\| (rc == 1))
	return rc;
	/*		/*
	* Assume that advantage of multipe MSIs is negated,		* If number of MSIs is less than number of ports then Sharing Last
	* so fallback to single MSI mode to save resources		* Message mode could be enforced. In this case assume that advantage
			* of multipe MSIs is negated and use single MSI mode instead.
	*/		*/
	pci_disable_msi(pdev);		if (rc < n_ports)
	if (!pci_enable_msi(pdev))		goto single_msi;

			nvec = rc;
			rc = pci_enable_msi_block(pdev, nvec);
			if (rc)
			goto intx;

			return nvec;

			single_msi:
			rc = pci_enable_msi(pdev);
			if (rc)
			goto intx;
	return 1;		return 1;
	}
	}

			intx:
	pci_intx(pdev, 1);		pci_intx(pdev, 1);
	return 0;		return 0;
	}		}
	@@ -1281,10 +1295,6 @@ static int ahci_init_one(struct pci_dev pdev, const struct pci_device_id ent)

	hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar];		hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar];

	n_msis = ahci_init_interrupts(pdev, hpriv);
	if (n_msis > 1)
	hpriv->flags \|= AHCI_HFLAG_MULTI_MSI;

	/* save initial config */		/* save initial config */
	ahci_pci_save_initial_config(pdev, hpriv);		ahci_pci_save_initial_config(pdev, hpriv);

	@@ -1339,6 +1349,10 @@ static int ahci_init_one(struct pci_dev pdev, const struct pci_device_id ent)
	*/		*/
	n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));		n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));

			n_msis = ahci_init_interrupts(pdev, n_ports, hpriv);
			if (n_msis > 1)
			hpriv->flags \|= AHCI_HFLAG_MULTI_MSI;

	host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);		host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);
	if (!host)		if (!host)
	return -ENOMEM;		return -ENOMEM;

drivers/pci/msi.c

+116 −34

Original line number	Original line	Diff line number	Diff line
	@@ -851,6 +851,31 @@ static int pci_msi_check_device(struct pci_dev *dev, int nvec, int type)
	return 0;		return 0;
	}		}

			/**
			* pci_msi_vec_count - Return the number of MSI vectors a device can send
			* @dev: device to report about
			*
			* This function returns the number of MSI vectors a device requested via
			* Multiple Message Capable register. It returns a negative errno if the
			* device is not capable sending MSI interrupts. Otherwise, the call succeeds
			* and returns a power of two, up to a maximum of 2^5 (32), according to the
			* MSI specification.
			**/
			int pci_msi_vec_count(struct pci_dev *dev)
			{
			int ret;
			u16 msgctl;

			if (!dev->msi_cap)
			return -EINVAL;

			pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);
			ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);

			return ret;
			}
			EXPORT_SYMBOL(pci_msi_vec_count);

	/**		/**
	* pci_enable_msi_block - configure device's MSI capability structure		* pci_enable_msi_block - configure device's MSI capability structure
	* @dev: device to configure		* @dev: device to configure
	@@ -867,13 +892,13 @@ static int pci_msi_check_device(struct pci_dev *dev, int nvec, int type)
	int pci_enable_msi_block(struct pci_dev *dev, int nvec)		int pci_enable_msi_block(struct pci_dev *dev, int nvec)
	{		{
	int status, maxvec;		int status, maxvec;
	u16 msgctl;

	if (!dev->msi_cap \|\| dev->current_state != PCI_D0)		if (dev->current_state != PCI_D0)
	return -EINVAL;		return -EINVAL;

	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);		maxvec = pci_msi_vec_count(dev);
	maxvec = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);		if (maxvec < 0)
			return maxvec;
	if (nvec > maxvec)		if (nvec > maxvec)
	return maxvec;		return maxvec;

	@@ -895,31 +920,6 @@ int pci_enable_msi_block(struct pci_dev *dev, int nvec)
	}		}
	EXPORT_SYMBOL(pci_enable_msi_block);		EXPORT_SYMBOL(pci_enable_msi_block);

	int pci_enable_msi_block_auto(struct pci_dev dev, int maxvec)
	{
	int ret, nvec;
	u16 msgctl;

	if (!dev->msi_cap \|\| dev->current_state != PCI_D0)
	return -EINVAL;

	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);
	ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);

	if (maxvec)
	*maxvec = ret;

	do {
	nvec = ret;
	ret = pci_enable_msi_block(dev, nvec);
	} while (ret > 0);

	if (ret < 0)
	return ret;
	return nvec;
	}
	EXPORT_SYMBOL(pci_enable_msi_block_auto);

	void pci_msi_shutdown(struct pci_dev *dev)		void pci_msi_shutdown(struct pci_dev *dev)
	{		{
	struct msi_desc *desc;		struct msi_desc *desc;
	@@ -957,19 +957,25 @@ void pci_disable_msi(struct pci_dev *dev)
	EXPORT_SYMBOL(pci_disable_msi);		EXPORT_SYMBOL(pci_disable_msi);

	/**		/**
	* pci_msix_table_size - return the number of device's MSI-X table entries		* pci_msix_vec_count - return the number of device's MSI-X table entries
	* @dev: pointer to the pci_dev data structure of MSI-X device function		* @dev: pointer to the pci_dev data structure of MSI-X device function
	*/
	int pci_msix_table_size(struct pci_dev *dev)		* This function returns the number of device's MSI-X table entries and
			* therefore the number of MSI-X vectors device is capable of sending.
			* It returns a negative errno if the device is not capable of sending MSI-X
			* interrupts.
			**/
			int pci_msix_vec_count(struct pci_dev *dev)
	{		{
	u16 control;		u16 control;

	if (!dev->msix_cap)		if (!dev->msix_cap)
	return 0;		return -EINVAL;

	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);		pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
	return msix_table_size(control);		return msix_table_size(control);
	}		}
			EXPORT_SYMBOL(pci_msix_vec_count);

	/**		/**
	* pci_enable_msix - configure device's MSI-X capability structure		* pci_enable_msix - configure device's MSI-X capability structure
	@@ -998,7 +1004,9 @@ int pci_enable_msix(struct pci_dev dev, struct msix_entry entries, int nvec)
	if (status)		if (status)
	return status;		return status;

	nr_entries = pci_msix_table_size(dev);		nr_entries = pci_msix_vec_count(dev);
			if (nr_entries < 0)
			return nr_entries;
	if (nvec > nr_entries)		if (nvec > nr_entries)
	return nr_entries;		return nr_entries;

	@@ -1103,3 +1111,77 @@ void pci_msi_init_pci_dev(struct pci_dev *dev)
	if (dev->msix_cap)		if (dev->msix_cap)
	msix_set_enable(dev, 0);		msix_set_enable(dev, 0);
	}		}

			/**
			* pci_enable_msi_range - configure device's MSI capability structure
			* @dev: device to configure
			* @minvec: minimal number of interrupts to configure
			* @maxvec: maximum number of interrupts to configure
			*
			* This function tries to allocate a maximum possible number of interrupts in a
			* range between @minvec and @maxvec. It returns a negative errno if an error
			* occurs. If it succeeds, it returns the actual number of interrupts allocated
			* and updates the @dev's irq member to the lowest new interrupt number;
			* the other interrupt numbers allocated to this device are consecutive.
			**/
			int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec)
			{
			int nvec = maxvec;
			int rc;

			if (maxvec < minvec)
			return -ERANGE;

			do {
			rc = pci_enable_msi_block(dev, nvec);
			if (rc < 0) {
			return rc;
			} else if (rc > 0) {
			if (rc < minvec)
			return -ENOSPC;
			nvec = rc;
			}
			} while (rc);

			return nvec;
			}
			EXPORT_SYMBOL(pci_enable_msi_range);

			/**
			* pci_enable_msix_range - configure device's MSI-X capability structure
			* @dev: pointer to the pci_dev data structure of MSI-X device function
			* @entries: pointer to an array of MSI-X entries
			* @minvec: minimum number of MSI-X irqs requested
			* @maxvec: maximum number of MSI-X irqs requested
			*
			* Setup the MSI-X capability structure of device function with a maximum
			* possible number of interrupts in the range between @minvec and @maxvec
			* upon its software driver call to request for MSI-X mode enabled on its
			* hardware device function. It returns a negative errno if an error occurs.
			* If it succeeds, it returns the actual number of interrupts allocated and
			* indicates the successful configuration of MSI-X capability structure
			* with new allocated MSI-X interrupts.
			**/
			int pci_enable_msix_range(struct pci_dev dev, struct msix_entry entries,
			int minvec, int maxvec)
			{
			int nvec = maxvec;
			int rc;

			if (maxvec < minvec)
			return -ERANGE;

			do {
			rc = pci_enable_msix(dev, entries, nvec);
			if (rc < 0) {
			return rc;
			} else if (rc > 0) {
			if (rc < minvec)
			return -ENOSPC;
			nvec = rc;
			}
			} while (rc);

			return nvec;
			}
			EXPORT_SYMBOL(pci_enable_msix_range);

drivers/pci/pcie/portdrv_core.c

+4 −3

Original line number	Original line	Diff line number	Diff line
	@@ -79,9 +79,10 @@ static int pcie_port_enable_msix(struct pci_dev dev, int vectors, int mask)
	u16 reg16;		u16 reg16;
	u32 reg32;		u32 reg32;

	nr_entries = pci_msix_table_size(dev);		nr_entries = pci_msix_vec_count(dev);
	if (!nr_entries)		if (nr_entries < 0)
	return -EINVAL;		return nr_entries;
			BUG_ON(!nr_entries);
	if (nr_entries > PCIE_PORT_MAX_MSIX_ENTRIES)		if (nr_entries > PCIE_PORT_MAX_MSIX_ENTRIES)
	nr_entries = PCIE_PORT_MAX_MSIX_ENTRIES;		nr_entries = PCIE_PORT_MAX_MSIX_ENTRIES;

include/linux/pci.h

+20 −7

Original line number	Original line	Diff line number	Diff line
	@@ -1166,13 +1166,12 @@ struct msix_entry {


	#ifndef CONFIG_PCI_MSI		#ifndef CONFIG_PCI_MSI
	static inline int pci_enable_msi_block(struct pci_dev *dev, int nvec)		static inline int pci_msi_vec_count(struct pci_dev *dev)
	{		{
	return -ENOSYS;		return -ENOSYS;
	}		}

	static inline int		static inline int pci_enable_msi_block(struct pci_dev *dev, int nvec)
	pci_enable_msi_block_auto(struct pci_dev dev, int maxvec)
	{		{
	return -ENOSYS;		return -ENOSYS;
	}		}
	@@ -1182,9 +1181,9 @@ static inline void pci_msi_shutdown(struct pci_dev *dev)
	static inline void pci_disable_msi(struct pci_dev *dev)		static inline void pci_disable_msi(struct pci_dev *dev)
	{ }		{ }

	static inline int pci_msix_table_size(struct pci_dev *dev)		static inline int pci_msix_vec_count(struct pci_dev *dev)
	{		{
	return 0;		return -ENOSYS;
	}		}
	static inline int pci_enable_msix(struct pci_dev *dev,		static inline int pci_enable_msix(struct pci_dev *dev,
	struct msix_entry *entries, int nvec)		struct msix_entry *entries, int nvec)
	@@ -1206,18 +1205,32 @@ static inline int pci_msi_enabled(void)
	{		{
	return 0;		return 0;
	}		}

			static inline int pci_enable_msi_range(struct pci_dev *dev, int minvec,
			int maxvec)
			{
			return -ENOSYS;
			}
			static inline int pci_enable_msix_range(struct pci_dev *dev,
			struct msix_entry *entries, int minvec, int maxvec)
			{
			return -ENOSYS;
			}
	#else		#else
			int pci_msi_vec_count(struct pci_dev *dev);
	int pci_enable_msi_block(struct pci_dev *dev, int nvec);		int pci_enable_msi_block(struct pci_dev *dev, int nvec);
	int pci_enable_msi_block_auto(struct pci_dev dev, int maxvec);
	void pci_msi_shutdown(struct pci_dev *dev);		void pci_msi_shutdown(struct pci_dev *dev);
	void pci_disable_msi(struct pci_dev *dev);		void pci_disable_msi(struct pci_dev *dev);
	int pci_msix_table_size(struct pci_dev *dev);		int pci_msix_vec_count(struct pci_dev *dev);
	int pci_enable_msix(struct pci_dev dev, struct msix_entry entries, int nvec);		int pci_enable_msix(struct pci_dev dev, struct msix_entry entries, int nvec);
	void pci_msix_shutdown(struct pci_dev *dev);		void pci_msix_shutdown(struct pci_dev *dev);
	void pci_disable_msix(struct pci_dev *dev);		void pci_disable_msix(struct pci_dev *dev);
	void msi_remove_pci_irq_vectors(struct pci_dev *dev);		void msi_remove_pci_irq_vectors(struct pci_dev *dev);
	void pci_restore_msi_state(struct pci_dev *dev);		void pci_restore_msi_state(struct pci_dev *dev);
	int pci_msi_enabled(void);		int pci_msi_enabled(void);
			int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec);
			int pci_enable_msix_range(struct pci_dev dev, struct msix_entry entries,
			int minvec, int maxvec);
	#endif		#endif

	#ifdef CONFIG_PCIEPORTBUS		#ifdef CONFIG_PCIEPORTBUS