diff options
author | Russell King <rmk@dyn-67.arm.linux.org.uk> | 2009-04-02 23:22:11 +0100 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-04-02 23:22:11 +0100 |
commit | cd02938a828f4b2098a074afb7454f106f2e8df5 (patch) | |
tree | 7b543fd6aa82a62dc3a9614c26f89daca83e77d5 /Documentation | |
parent | 9d681f3a1b27fdfc17ea251cf8d5f627dab34670 (diff) | |
parent | 172ef275444efa12d834fb9d1b1acdac92db47f7 (diff) |
Merge branch 'smsc911x-armplatforms' of git://github.com/steveglen/linux-2.6
Diffstat (limited to 'Documentation')
54 files changed, 1492 insertions, 1321 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index e638e15a889..97ad190e13a 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -41,6 +41,49 @@ Description: for the device and attempt to bind to it. For example: # echo "8086 10f5" > /sys/bus/pci/drivers/foo/new_id +What: /sys/bus/pci/drivers/.../remove_id +Date: February 2009 +Contact: Chris Wright <chrisw@sous-sol.org> +Description: + Writing a device ID to this file will remove an ID + that was dynamically added via the new_id sysfs entry. + The format for the device ID is: + VVVV DDDD SVVV SDDD CCCC MMMM. That is Vendor ID, Device + ID, Subsystem Vendor ID, Subsystem Device ID, Class, + and Class Mask. The Vendor ID and Device ID fields are + required, the rest are optional. After successfully + removing an ID, the driver will no longer support the + device. This is useful to ensure auto probing won't + match the driver to the device. For example: + # echo "8086 10f5" > /sys/bus/pci/drivers/foo/remove_id + +What: /sys/bus/pci/rescan +Date: January 2009 +Contact: Linux PCI developers <linux-pci@vger.kernel.org> +Description: + Writing a non-zero value to this attribute will + force a rescan of all PCI buses in the system, and + re-discover previously removed devices. + Depends on CONFIG_HOTPLUG. + +What: /sys/bus/pci/devices/.../remove +Date: January 2009 +Contact: Linux PCI developers <linux-pci@vger.kernel.org> +Description: + Writing a non-zero value to this attribute will + hot-remove the PCI device and any of its children. + Depends on CONFIG_HOTPLUG. + +What: /sys/bus/pci/devices/.../rescan +Date: January 2009 +Contact: Linux PCI developers <linux-pci@vger.kernel.org> +Description: + Writing a non-zero value to this attribute will + force a rescan of the device's parent bus and all + child buses, and re-discover devices removed earlier + from this part of the device tree. + Depends on CONFIG_HOTPLUG. + What: /sys/bus/pci/devices/.../vpd Date: February 2008 Contact: Ben Hutchings <bhutchings@solarflare.com> @@ -52,3 +95,30 @@ Description: that some devices may have malformatted data. If the underlying VPD has a writable section then the corresponding section of this file will be writable. + +What: /sys/bus/pci/devices/.../virtfnN +Date: March 2009 +Contact: Yu Zhao <yu.zhao@intel.com> +Description: + This symbolic link appears when hardware supports the SR-IOV + capability and the Physical Function driver has enabled it. + The symbolic link points to the PCI device sysfs entry of the + Virtual Function whose index is N (0...MaxVFs-1). + +What: /sys/bus/pci/devices/.../dep_link +Date: March 2009 +Contact: Yu Zhao <yu.zhao@intel.com> +Description: + This symbolic link appears when hardware supports the SR-IOV + capability and the Physical Function driver has enabled it, + and this device has vendor specific dependencies with others. + The symbolic link points to the PCI device sysfs entry of + Physical Function this device depends on. + +What: /sys/bus/pci/devices/.../physfn +Date: March 2009 +Contact: Yu Zhao <yu.zhao@intel.com> +Description: + This symbolic link appears when a device is a Virtual Function. + The symbolic link points to the PCI device sysfs entry of the + Physical Function this device associates with. diff --git a/Documentation/ABI/testing/sysfs-fs-ext4 b/Documentation/ABI/testing/sysfs-fs-ext4 new file mode 100644 index 00000000000..4e79074de28 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-fs-ext4 @@ -0,0 +1,81 @@ +What: /sys/fs/ext4/<disk>/mb_stats +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + Controls whether the multiblock allocator should + collect statistics, which are shown during the unmount. + 1 means to collect statistics, 0 means not to collect + statistics + +What: /sys/fs/ext4/<disk>/mb_group_prealloc +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + The multiblock allocator will round up allocation + requests to a multiple of this tuning parameter if the + stripe size is not set in the ext4 superblock + +What: /sys/fs/ext4/<disk>/mb_max_to_scan +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + The maximum number of extents the multiblock allocator + will search to find the best extent + +What: /sys/fs/ext4/<disk>/mb_min_to_scan +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + The minimum number of extents the multiblock allocator + will search to find the best extent + +What: /sys/fs/ext4/<disk>/mb_order2_req +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + Tuning parameter which controls the minimum size for + requests (as a power of 2) where the buddy cache is + used + +What: /sys/fs/ext4/<disk>/mb_stream_req +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + Files which have fewer blocks than this tunable + parameter will have their blocks allocated out of a + block group specific preallocation pool, so that small + files are packed closely together. Each large file + will have its blocks allocated out of its own unique + preallocation pool. + +What: /sys/fs/ext4/<disk>/inode_readahead +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + Tuning parameter which controls the maximum number of + inode table blocks that ext4's inode table readahead + algorithm will pre-read into the buffer cache + +What: /sys/fs/ext4/<disk>/delayed_allocation_blocks +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + This file is read-only and shows the number of blocks + that are dirty in the page cache, but which do not + have their location in the filesystem allocated yet. + +What: /sys/fs/ext4/<disk>/lifetime_write_kbytes +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + This file is read-only and shows the number of kilobytes + of data that have been written to this filesystem since it was + created. + +What: /sys/fs/ext4/<disk>/session_write_kbytes +Date: March 2008 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + This file is read-only and shows the number of + kilobytes of data that have been written to this + filesystem since it was mounted. diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index 2a3fcc55e98..d9aa43d78bc 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -609,3 +609,109 @@ size is the size (and should be a page-sized multiple). The return value will be either a pointer to the processor virtual address of the memory, or an error (via PTR_ERR()) if any part of the region is occupied. + +Part III - Debug drivers use of the DMA-API +------------------------------------------- + +The DMA-API as described above as some constraints. DMA addresses must be +released with the corresponding function with the same size for example. With +the advent of hardware IOMMUs it becomes more and more important that drivers +do not violate those constraints. In the worst case such a violation can +result in data corruption up to destroyed filesystems. + +To debug drivers and find bugs in the usage of the DMA-API checking code can +be compiled into the kernel which will tell the developer about those +violations. If your architecture supports it you can select the "Enable +debugging of DMA-API usage" option in your kernel configuration. Enabling this +option has a performance impact. Do not enable it in production kernels. + +If you boot the resulting kernel will contain code which does some bookkeeping +about what DMA memory was allocated for which device. If this code detects an +error it prints a warning message with some details into your kernel log. An +example warning message may look like this: + +------------[ cut here ]------------ +WARNING: at /data2/repos/linux-2.6-iommu/lib/dma-debug.c:448 + check_unmap+0x203/0x490() +Hardware name: +forcedeth 0000:00:08.0: DMA-API: device driver frees DMA memory with wrong + function [device address=0x00000000640444be] [size=66 bytes] [mapped as +single] [unmapped as page] +Modules linked in: nfsd exportfs bridge stp llc r8169 +Pid: 0, comm: swapper Tainted: G W 2.6.28-dmatest-09289-g8bb99c0 #1 +Call Trace: + <IRQ> [<ffffffff80240b22>] warn_slowpath+0xf2/0x130 + [<ffffffff80647b70>] _spin_unlock+0x10/0x30 + [<ffffffff80537e75>] usb_hcd_link_urb_to_ep+0x75/0xc0 + [<ffffffff80647c22>] _spin_unlock_irqrestore+0x12/0x40 + [<ffffffff8055347f>] ohci_urb_enqueue+0x19f/0x7c0 + [<ffffffff80252f96>] queue_work+0x56/0x60 + [<ffffffff80237e10>] enqueue_task_fair+0x20/0x50 + [<ffffffff80539279>] usb_hcd_submit_urb+0x379/0xbc0 + [<ffffffff803b78c3>] cpumask_next_and+0x23/0x40 + [<ffffffff80235177>] find_busiest_group+0x207/0x8a0 + [<ffffffff8064784f>] _spin_lock_irqsave+0x1f/0x50 + [<ffffffff803c7ea3>] check_unmap+0x203/0x490 + [<ffffffff803c8259>] debug_dma_unmap_page+0x49/0x50 + [<ffffffff80485f26>] nv_tx_done_optimized+0xc6/0x2c0 + [<ffffffff80486c13>] nv_nic_irq_optimized+0x73/0x2b0 + [<ffffffff8026df84>] handle_IRQ_event+0x34/0x70 + [<ffffffff8026ffe9>] handle_edge_irq+0xc9/0x150 + [<ffffffff8020e3ab>] do_IRQ+0xcb/0x1c0 + [<ffffffff8020c093>] ret_from_intr+0x0/0xa + <EOI> <4>---[ end trace f6435a98e2a38c0e ]--- + +The driver developer can find the driver and the device including a stacktrace +of the DMA-API call which caused this warning. + +Per default only the first error will result in a warning message. All other +errors will only silently counted. This limitation exist to prevent the code +from flooding your kernel log. To support debugging a device driver this can +be disabled via debugfs. See the debugfs interface documentation below for +details. + +The debugfs directory for the DMA-API debugging code is called dma-api/. In +this directory the following files can currently be found: + + dma-api/all_errors This file contains a numeric value. If this + value is not equal to zero the debugging code + will print a warning for every error it finds + into the kernel log. Be carefull with this + option. It can easily flood your logs. + + dma-api/disabled This read-only file contains the character 'Y' + if the debugging code is disabled. This can + happen when it runs out of memory or if it was + disabled at boot time + + dma-api/error_count This file is read-only and shows the total + numbers of errors found. + + dma-api/num_errors The number in this file shows how many + warnings will be printed to the kernel log + before it stops. This number is initialized to + one at system boot and be set by writing into + this file + + dma-api/min_free_entries + This read-only file can be read to get the + minimum number of free dma_debug_entries the + allocator has ever seen. If this value goes + down to zero the code will disable itself + because it is not longer reliable. + + dma-api/num_free_entries + The current number of free dma_debug_entries + in the allocator. + +If you have this code compiled into your kernel it will be enabled by default. +If you want to boot without the bookkeeping anyway you can provide +'dma_debug=off' as a boot parameter. This will disable DMA-API debugging. +Notice that you can not enable it again at runtime. You have to reboot to do +so. + +When the code disables itself at runtime this is most likely because it ran +out of dma_debug_entries. These entries are preallocated at boot. The number +of preallocated entries is defined per architecture. If it is too low for you +boot with 'dma_debug_entries=<your_desired_number>' to overwrite the +architectural default. diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl index bc962cda650..58c194572c7 100644 --- a/Documentation/DocBook/kernel-api.tmpl +++ b/Documentation/DocBook/kernel-api.tmpl @@ -199,6 +199,7 @@ X!Edrivers/pci/hotplug.c --> !Edrivers/pci/probe.c !Edrivers/pci/rom.c +!Edrivers/pci/iov.c </sect1> <sect1><title>PCI Hotplug Support Library</title> !Edrivers/pci/hotplug/pci_hotplug_core.c diff --git a/Documentation/DocBook/procfs_example.c b/Documentation/DocBook/procfs_example.c index 8c6396e4bf3..a5b11793b1e 100644 --- a/Documentation/DocBook/procfs_example.c +++ b/Documentation/DocBook/procfs_example.c @@ -117,9 +117,6 @@ static int __init init_procfs_example(void) rv = -ENOMEM; goto out; } - - example_dir->owner = THIS_MODULE; - /* create jiffies using convenience function */ jiffies_file = create_proc_read_entry("jiffies", 0444, example_dir, @@ -130,8 +127,6 @@ static int __init init_procfs_example(void) goto no_jiffies; } - jiffies_file->owner = THIS_MODULE; - /* create foo and bar files using same callback * functions */ @@ -146,7 +141,6 @@ static int __init init_procfs_example(void) foo_file->data = &foo_data; foo_file->read_proc = proc_read_foobar; foo_file->write_proc = proc_write_foobar; - foo_file->owner = THIS_MODULE; bar_file = create_proc_entry("bar", 0644, example_dir); if(bar_file == NULL) { @@ -159,7 +153,6 @@ static int __init init_procfs_example(void) bar_file->data = &bar_data; bar_file->read_proc = proc_read_foobar; bar_file->write_proc = proc_write_foobar; - bar_file->owner = THIS_MODULE; /* create symlink */ symlink = proc_symlink("jiffies_too", example_dir, @@ -169,8 +162,6 @@ static int __init init_procfs_example(void) goto no_symlink; } - symlink->owner = THIS_MODULE; - /* everything OK */ printk(KERN_INFO "%s %s initialised\n", MODULE_NAME, MODULE_VERS); diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt index 256defd7e17..dcf7acc720e 100644 --- a/Documentation/PCI/MSI-HOWTO.txt +++ b/Documentation/PCI/MSI-HOWTO.txt @@ -4,506 +4,356 @@ Revised Feb 12, 2004 by Martine Silbermann email: Martine.Silbermann@hp.com Revised Jun 25, 2004 by Tom L Nguyen + Revised Jul 9, 2008 by Matthew Wilcox <willy@linux.intel.com> + Copyright 2003, 2008 Intel Corporation 1. About this guide -This guide describes the basics of Message Signaled Interrupts (MSI), -the advantages of using MSI over traditional interrupt mechanisms, -and how to enable your driver to use MSI or MSI-X. Also included is -a Frequently Asked Questions (FAQ) section. - -1.1 Terminology - -PCI devices can be single-function or multi-function. In either case, -when this text talks about enabling or disabling MSI on a "device -function," it is referring to one specific PCI device and function and -not to all functions on a PCI device (unless the PCI device has only -one function). - -2. Copyright 2003 Intel Corporation - -3. What is MSI/MSI-X? - -Message Signaled Interrupt (MSI), as described in the PCI Local Bus -Specification Revision 2.3 or later, is an optional feature, and a -required feature for PCI Express devices. MSI enables a device function -to request service by sending an Inbound Memory Write on its PCI bus to -the FSB as a Message Signal Interrupt transaction. Because MSI is -generated in the form of a Memory Write, all transaction conditions, -such as a Retry, Master-Abort, Target-Abort or normal completion, are -supported. - -A PCI device that supports MSI must also support pin IRQ assertion -interrupt mechanism to provide backward compatibility for systems that -do not support MSI. In systems which support MSI, the bus driver is -responsible for initializing the message address and message data of -the device function's MSI/MSI-X capability structure during device -initial configuration. - -An MSI capable device function indicates MSI support by implementing -the MSI/MSI-X capability structure in its PCI capability list. The -device function may implement both the MSI capability structure and -the MSI-X capability structure; however, the bus driver should not -enable both. - -The MSI capability structure contains Message Control register, -Message Address register and Message Data register. These registers -provide the bus driver control over MSI. The Message Control register -indicates the MSI capability supported by the device. The Message -Address register specifies the target address and the Message Data -register specifies the characteristics of the message. To request -service, the device function writes the content of the Message Data -register to the target address. The device and its software driver -are prohibited from writing to these registers. - -The MSI-X capability structure is an optional extension to MSI. It -uses an independent and separate capability structure. There are -some key advantages to implementing the MSI-X capability structure -over the MSI capability structure as described below. - - - Support a larger maximum number of vectors per function. - - - Provide the ability for system software to configure - each vector with an independent message address and message - data, specified by a table that resides in Memory Space. - - - MSI and MSI-X both support per-vector masking. Per-vector - masking is an optional extension of MSI but a required - feature for MSI-X. Per-vector masking provides the kernel the - ability to mask/unmask a single MSI while running its - interrupt service routine. If per-vector masking is - not supported, then the device driver should provide the - hardware/software synchronization to ensure that the device - generates MSI when the driver wants it to do so. - -4. Why use MSI? - -As a benefit to the simplification of board design, MSI allows board -designers to remove out-of-band interrupt routing. MSI is another -step towards a legacy-free environment. - -Due to increasing pressure on chipset and processor packages to -reduce pin count, the need for interrupt pins is expected to -diminish over time. Devices, due to pin constraints, may implement -messages to increase performance. - -PCI Express endpoints uses INTx emulation (in-band messages) instead -of IRQ pin assertion. Using INTx emulation requires interrupt -sharing among devices connected to the same node (PCI bridge) while -MSI is unique (non-shared) and does not require BIOS configuration -support. As a result, the PCI Express technology requires MSI -support for better interrupt performance. - -Using MSI enables the device functions to support two or more -vectors, which can be configured to target different CPUs to -increase scalability. - -5. Configuring a driver to use MSI/MSI-X - -By default, the kernel will not enable MSI/MSI-X on all devices that -support this capability. The CONFIG_PCI_MSI kernel option -must be selected to enable MSI/MSI-X support. - -5.1 Including MSI/MSI-X support into the kernel - -To allow MSI/MSI-X capable device drivers to selectively enable -MSI/MSI-X (using pci_enable_msi()/pci_enable_msix() as described -below), the VECTOR based scheme needs to be enabled by setting -CONFIG_PCI_MSI during kernel config. - -Since the target of the inbound message is the local APIC, providing -CONFIG_X86_LOCAL_APIC must be enabled as well as CONFIG_PCI_MSI. - -5.2 Configuring for MSI support - -Due to the non-contiguous fashion in vector assignment of the -existing Linux kernel, this version does not support multiple -messages regardless of a device function is capable of supporting -more than one vector. To enable MSI on a device function's MSI -capability structure requires a device driver to call the function -pci_enable_msi() explicitly. - -5.2.1 API pci_enable_msi +This guide describes the basics of Message Signaled Interrupts (MSIs), +the advantages of using MSI over traditional interrupt mechanisms, how +to change your driver to use MSI or MSI-X and some basic diagnostics to +try if a device doesn't support MSIs. -int pci_enable_msi(struct pci_dev *dev) -With this new API, a device driver that wants to have MSI -enabled on its device function must call this API to enable MSI. -A successful call will initialize the MSI capability structure -with ONE vector, regardless of whether a device function is -capable of supporting multiple messages. This vector replaces the -pre-assigned dev->irq with a new MSI vector. To avoid a conflict -of the new assigned vector with existing pre-assigned vector requires -a device driver to call this API before calling request_irq(). +2. What are MSIs? -5.2.2 API pci_disable_msi +A Message Signaled Interrupt is a write from the device to a special +address which causes an interrupt to be received by the CPU. -void pci_disable_msi(struct pci_dev *dev) +The MSI capability was first specified in PCI 2.2 and was later enhanced +in PCI 3.0 to allow each interrupt to be masked individually. The MSI-X +capability was also introduced with PCI 3.0. It supports more interrupts +per device than MSI and allows interrupts to be independently configured. -This API should always be used to undo the effect of pci_enable_msi() -when a device driver is unloading. This API restores dev->irq with -the pre-assigned IOAPIC vector and switches a device's interrupt -mode to PCI pin-irq assertion/INTx emulation mode. - -Note that a device driver should always call free_irq() on the MSI vector -that it has done request_irq() on before calling this API. Failure to do -so results in a BUG_ON() and a device will be left with MSI enabled and -leaks its vector. - -5.2.3 MSI mode vs. legacy mode diagram - -The below diagram shows the events which switch the interrupt -mode on the MSI-capable device function between MSI mode and -PIN-IRQ assertion mode. - - ------------ pci_enable_msi ------------------------ - | | <=============== | | - | MSI MODE | | PIN-IRQ ASSERTION MODE | - | | ===============> | | - ------------ pci_disable_msi ------------------------ - - -Figure 1. MSI Mode vs. Legacy Mode - -In Figure 1, a device operates by default in legacy mode. Legacy -in this context means PCI pin-irq assertion or PCI-Express INTx -emulation. A successful MSI request (using pci_enable_msi()) switches -a device's interrupt mode to MSI mode. A pre-assigned IOAPIC vector -stored in dev->irq will be saved by the PCI subsystem and a new -assigned MSI vector will replace dev->irq. - -To return back to its default |