Commit d158fc7f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'pci-v3.14-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci 

Pull PCI updates from Bjorn Helgaas:
 "The most interesting thing here is the change to enable INTx (by
  clearing PCI_COMMAND_INTX_DISABLE) if the BIOS left INTx disabled.
  Apparently the Baytrail BIOS does this, which means EHCI doesn't work.

  Also, fix an AHCI MSI regression and other issues with the recent MSI
  changes.  This also adds pci_enable_msi_exact() and
  pci_enable_msix_exact(), which aren't regression fixes, but will keep
  us from touching drivers twice (once to stop using the deprecated
  pci_enable_msi(), etc., and again to use the *_exact() variants).

  There's also a minor MVEBU fix.

  Summary:

  MSI:
    - Fix AHCI single-MSI fallback (Alexander Gordeev)
    - Fix populate_msi_sysfs() error paths (Greg Kroah-Hartman)
    - Fix htmldocs problem (Masanari Iida)
    - Add pci_enable_msi_exact() and pci_enable_msix_exact() (Alexander Gordeev)
    - Update documentation (Alexander Gordeev)

  Miscellaneous:
    - mvebu: expose device ID & revision via lspci (Andrew Lunn)
    - Enable INTx if the BIOS left them disabled (Bjorn Helgaas)"

* tag 'pci-v3.14-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  ahci: Fix broken fallback to single MSI mode
  PCI: Enable INTx if BIOS left them disabled
  PCI/MSI: Add pci_enable_msi_exact() and pci_enable_msix_exact()
  PCI/MSI: Fix cut-and-paste errors in documentation
  PCI/MSI: Add pci_enable_msi() documentation back
  PCI/MSI: Fix pci_msix_vec_count() htmldocs failure
  PCI/MSI: Fix leak of msi_attrs
  PCI/MSI: Check kmalloc() return value, fix leak of name
  PCI: mvebu: Use Device ID and revision from underlying endpoint
parents 54dfffde fc40363b

Documentation/PCI/MSI-HOWTO.txt

+109 −10
Original line number Diff line number Diff line
@@ -82,7 +82,19 @@ 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

device.



4.2.1 pci_enable_msi_range

4.2.1 pci_enable_msi



int pci_enable_msi(struct pci_dev *dev)



A successful call allocates ONE interrupt to the device, regardless

of how many MSIs the device supports.  The device is switched from

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_range



int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec)
@@ -147,6 +159,11 @@ static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec) 
	return pci_enable_msi_range(pdev, nvec, nvec);

}



Note, unlike pci_enable_msi_exact() function, which could be also used to

enable a particular number of MSI-X interrupts, pci_enable_msi_range()

returns either a negative errno or 'nvec' (not negative errno or 0 - as

pci_enable_msi_exact() does).



4.2.1.3 Single MSI mode



The most notorious example of the request type described above is
@@ -158,7 +175,27 @@ 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

Note, unlike pci_enable_msi() function, which could be also used to

enable the single MSI mode, pci_enable_msi_range() returns either a

negative errno or 1 (not negative errno or 0 - as pci_enable_msi()

does).



4.2.3 pci_enable_msi_exact



int pci_enable_msi_exact(struct pci_dev *dev, int nvec)



This variation on pci_enable_msi_range() call allows a device driver to

request exactly 'nvec' MSIs.



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.



By contrast with pci_enable_msi_range() function, pci_enable_msi_exact()

returns zero in case of success, which indicates MSI interrupts have been

successfully allocated.



4.2.4 pci_disable_msi



void pci_disable_msi(struct pci_dev *dev)
@@ -172,7 +209,7 @@ on any interrupt for which it previously called request_irq(). 
Failure to do so results in a BUG_ON(), leaving the device with

MSI enabled and thus leaking its vector.



4.2.3 pci_msi_vec_count

4.2.4 pci_msi_vec_count



int pci_msi_vec_count(struct pci_dev *dev)
@@ -257,7 +294,7 @@ 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)

{

	return pci_enable_msi_range(adapter->pdev, adapter->msix_entries,

	return pci_enable_msix_range(adapter->pdev, adapter->msix_entries,

				     1, nvec);

}
@@ -269,7 +306,7 @@ 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,

	return pci_enable_msix_range(adapter->pdev, adapter->msix_entries,

				     FOO_DRIVER_MINIMUM_NVEC, nvec);

}
@@ -282,10 +319,15 @@ parameters: 


static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)

{

	return pci_enable_msi_range(adapter->pdev, adapter->msix_entries,

	return pci_enable_msix_range(adapter->pdev, adapter->msix_entries,

				     nvec, nvec);

}



Note, unlike pci_enable_msix_exact() function, which could be also used to

enable a particular number of MSI-X interrupts, pci_enable_msix_range()

returns either a negative errno or 'nvec' (not negative errno or 0 - as

pci_enable_msix_exact() does).



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
@@ -332,7 +374,64 @@ 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_enable_msix_exact



int pci_enable_msix_exact(struct pci_dev *dev,

			  struct msix_entry *entries, int nvec)



This variation on pci_enable_msix_range() call allows a device driver to

request exactly 'nvec' MSI-Xs.



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

this device.



By contrast with pci_enable_msix_range() function, pci_enable_msix_exact()

returns zero in case of success, which indicates MSI-X interrupts have been

successfully allocated.



Another version of a routine that enables MSI-X mode for a device with

specific requirements described in chapter 4.3.1.3 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_exact(adapter->pdev,

				   adapter->msix_entries, maxvec);



	/*

	 * -ENOSPC is the only error code allowed to be analyzed

	 */

	if (rc == -ENOSPC) {

		if (maxvec == 1)

			return -ENOSPC;



		maxvec /= 2;



		if (minvec > maxvec)

			return -ENOSPC;



		goto retry;

	} else if (rc < 0) {

		return rc;

	}



	return maxvec;

}



4.3.3 pci_disable_msix



void pci_disable_msix(struct pci_dev *dev)

drivers/ata/ahci.c

+3 −1
Original line number Diff line number Diff line
@@ -1184,8 +1184,10 @@ static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports, 


	nvec = rc;

	rc = pci_enable_msi_block(pdev, nvec);

	if (rc)

	if (rc < 0)

		goto intx;

	else if (rc > 0)

		goto single_msi;



	return nvec;

drivers/pci/host/pci-mvebu.c

+2 −9
Original line number Diff line number Diff line
@@ -60,14 +60,6 @@ 
#define PCIE_DEBUG_CTRL         0x1a60

#define  PCIE_DEBUG_SOFT_RESET		BIT(20)



/*

 * This product ID is registered by Marvell, and used when the Marvell

 * SoC is not the root complex, but an endpoint on the PCIe bus. It is

 * therefore safe to re-use this PCI ID for our emulated PCI-to-PCI

 * bridge.

 */

#define MARVELL_EMULATED_PCI_PCI_BRIDGE_ID 0x7846



/* PCI configuration space of a PCI-to-PCI bridge */

struct mvebu_sw_pci_bridge {

	u16 vendor;
@@ -388,7 +380,8 @@ static void mvebu_sw_pci_bridge_init(struct mvebu_pcie_port *port) 


	bridge->class = PCI_CLASS_BRIDGE_PCI;

	bridge->vendor = PCI_VENDOR_ID_MARVELL;

	bridge->device = MARVELL_EMULATED_PCI_PCI_BRIDGE_ID;

	bridge->device = mvebu_readl(port, PCIE_DEV_ID_OFF) >> 16;

	bridge->revision = mvebu_readl(port, PCIE_DEV_REV_OFF) & 0xff;

	bridge->header_type = PCI_HEADER_TYPE_BRIDGE;

	bridge->cache_line_size = 0x10;

drivers/pci/msi.c

+8 −2
Original line number Diff line number Diff line
@@ -545,9 +545,15 @@ static int populate_msi_sysfs(struct pci_dev *pdev) 
		return -ENOMEM;

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

		char *name = kmalloc(20, GFP_KERNEL);

		if (!name)

			goto error_attrs;



		msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);

		if (!msi_dev_attr)

		if (!msi_dev_attr) {

			kfree(name);

			goto error_attrs;

		}



		sprintf(name, "%d", entry->irq);

		sysfs_attr_init(&msi_dev_attr->attr);

		msi_dev_attr->attr.name = name;
@@ -589,6 +595,7 @@ error_attrs: 
		++count;

		msi_attr = msi_attrs[count];

	}

	kfree(msi_attrs);

	return ret;

}
@@ -959,7 +966,6 @@ EXPORT_SYMBOL(pci_disable_msi); 
/**

 * 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



 * 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

drivers/pci/pci.c

+10 −0
Original line number Diff line number Diff line
@@ -1181,6 +1181,8 @@ EXPORT_SYMBOL_GPL(pci_load_and_free_saved_state); 
static int do_pci_enable_device(struct pci_dev *dev, int bars)

{

	int err;

	u16 cmd;

	u8 pin;



	err = pci_set_power_state(dev, PCI_D0);

	if (err < 0 && err != -EIO)
@@ -1190,6 +1192,14 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars) 
		return err;

	pci_fixup_device(pci_fixup_enable, dev);



	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);

	if (pin) {

		pci_read_config_word(dev, PCI_COMMAND, &cmd);

		if (cmd & PCI_COMMAND_INTX_DISABLE)

			pci_write_config_word(dev, PCI_COMMAND,

					      cmd & ~PCI_COMMAND_INTX_DISABLE);

	}



	return 0;

}

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