From cadf8106661c061ab5041282a8e088de4e470526 Mon Sep 17 00:00:00 2001 From: Alexander Dahl Date: Sat, 28 Jan 2017 10:45:32 +0100 Subject: doc: convert UIO howto from docbook to sphinx Converted with tmplcvt. Only some tiny things needed manual fixing. Signed-off-by: Alexander Dahl Cc: Hans-Jürgen Koch Cc: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- Documentation/DocBook/Makefile | 2 +- Documentation/DocBook/uio-howto.tmpl | 1112 ---------------------------------- 2 files changed, 1 insertion(+), 1113 deletions(-) delete mode 100644 Documentation/DocBook/uio-howto.tmpl (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index a6eb7dcd4dd5..5fd8f5effd0c 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -11,7 +11,7 @@ DOCBOOKS := z8530book.xml \ writing_usb_driver.xml networking.xml \ kernel-api.xml filesystems.xml lsm.xml kgdb.xml \ gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \ - genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \ + genericirq.xml s390-drivers.xml scsi.xml \ sh.xml regulator.xml w1.xml \ writing_musb_glue_layer.xml iio.xml diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl deleted file mode 100644 index 5210f8a577c6..000000000000 --- a/Documentation/DocBook/uio-howto.tmpl +++ /dev/null @@ -1,1112 +0,0 @@ - - - - - -The Userspace I/O HOWTO - - - Hans-Jürgen - Koch - Linux developer, Linutronix - - - Linutronix - - -
- hjk@hansjkoch.de -
- - - - - 2006-2008 - Hans-Jürgen Koch. - - - 2009 - Red Hat Inc, Michael S. Tsirkin (mst@redhat.com) - - - - -This documentation is Free Software licensed under the terms of the -GPL version 2. - - - -2006-12-11 - - - This HOWTO describes concept and usage of Linux kernel's - Userspace I/O system. - - - - - 0.10 - 2016-10-17 - sch - Added generic hyperv driver - - - - 0.9 - 2009-07-16 - mst - Added generic pci driver - - - - 0.8 - 2008-12-24 - hjk - Added name attributes in mem and portio sysfs directories. - - - - 0.7 - 2008-12-23 - hjk - Added generic platform drivers and offset attribute. - - - 0.6 - 2008-12-05 - hjk - Added description of portio sysfs attributes. - - - 0.5 - 2008-05-22 - hjk - Added description of write() function. - - - 0.4 - 2007-11-26 - hjk - Removed section about uio_dummy. - - - 0.3 - 2007-04-29 - hjk - Added section about userspace drivers. - - - 0.2 - 2007-02-13 - hjk - Update after multiple mappings were added. - - - 0.1 - 2006-12-11 - hjk - First draft. - - - - - - -About this document - - - -Translations - -If you know of any translations for this document, or you are -interested in translating it, please email me -hjk@hansjkoch.de. - - - - -Preface - - For many types of devices, creating a Linux kernel driver is - overkill. All that is really needed is some way to handle an - interrupt and provide access to the memory space of the - device. The logic of controlling the device does not - necessarily have to be within the kernel, as the device does - not need to take advantage of any of other resources that the - kernel provides. One such common class of devices that are - like this are for industrial I/O cards. - - - To address this situation, the userspace I/O system (UIO) was - designed. For typical industrial I/O cards, only a very small - kernel module is needed. The main part of the driver will run in - user space. This simplifies development and reduces the risk of - serious bugs within a kernel module. - - - Please note that UIO is not an universal driver interface. Devices - that are already handled well by other kernel subsystems (like - networking or serial or USB) are no candidates for an UIO driver. - Hardware that is ideally suited for an UIO driver fulfills all of - the following: - - - - The device has memory that can be mapped. The device can be - controlled completely by writing to this memory. - - - The device usually generates interrupts. - - - The device does not fit into one of the standard kernel - subsystems. - - - - - -Acknowledgments - I'd like to thank Thomas Gleixner and Benedikt Spranger of - Linutronix, who have not only written most of the UIO code, but also - helped greatly writing this HOWTO by giving me all kinds of background - information. - - - -Feedback - Find something wrong with this document? (Or perhaps something - right?) I would love to hear from you. Please email me at - hjk@hansjkoch.de. - - - - - -About UIO - -If you use UIO for your card's driver, here's what you get: - - - - only one small kernel module to write and maintain. - - - develop the main part of your driver in user space, - with all the tools and libraries you're used to. - - - bugs in your driver won't crash the kernel. - - - updates of your driver can take place without recompiling - the kernel. - - - - -How UIO works - - Each UIO device is accessed through a device file and several - sysfs attribute files. The device file will be called - /dev/uio0 for the first device, and - /dev/uio1, /dev/uio2 - and so on for subsequent devices. - - - /dev/uioX is used to access the - address space of the card. Just use - mmap() to access registers or RAM - locations of your card. - - - - Interrupts are handled by reading from - /dev/uioX. A blocking - read() from - /dev/uioX will return as soon as an - interrupt occurs. You can also use - select() on - /dev/uioX to wait for an interrupt. The - integer value read from /dev/uioX - represents the total interrupt count. You can use this number - to figure out if you missed some interrupts. - - - For some hardware that has more than one interrupt source internally, - but not separate IRQ mask and status registers, there might be - situations where userspace cannot determine what the interrupt source - was if the kernel handler disables them by writing to the chip's IRQ - register. In such a case, the kernel has to disable the IRQ completely - to leave the chip's register untouched. Now the userspace part can - determine the cause of the interrupt, but it cannot re-enable - interrupts. Another cornercase is chips where re-enabling interrupts - is a read-modify-write operation to a combined IRQ status/acknowledge - register. This would be racy if a new interrupt occurred - simultaneously. - - - To address these problems, UIO also implements a write() function. It - is normally not used and can be ignored for hardware that has only a - single interrupt source or has separate IRQ mask and status registers. - If you need it, however, a write to /dev/uioX - will call the irqcontrol() function implemented - by the driver. You have to write a 32-bit value that is usually either - 0 or 1 to disable or enable interrupts. If a driver does not implement - irqcontrol(), write() will - return with -ENOSYS. - - - - To handle interrupts properly, your custom kernel module can - provide its own interrupt handler. It will automatically be - called by the built-in handler. - - - - For cards that don't generate interrupts but need to be - polled, there is the possibility to set up a timer that - triggers the interrupt handler at configurable time intervals. - This interrupt simulation is done by calling - uio_event_notify() - from the timer's event handler. - - - - Each driver provides attributes that are used to read or write - variables. These attributes are accessible through sysfs - files. A custom kernel driver module can add its own - attributes to the device owned by the uio driver, but not added - to the UIO device itself at this time. This might change in the - future if it would be found to be useful. - - - - The following standard attributes are provided by the UIO - framework: - - - - - name: The name of your device. It is - recommended to use the name of your kernel module for this. - - - - - version: A version string defined by your - driver. This allows the user space part of your driver to deal - with different versions of the kernel module. - - - - - event: The total number of interrupts - handled by the driver since the last time the device node was - read. - - - - - These attributes appear under the - /sys/class/uio/uioX directory. Please - note that this directory might be a symlink, and not a real - directory. Any userspace code that accesses it must be able - to handle this. - - - Each UIO device can make one or more memory regions available for - memory mapping. This is necessary because some industrial I/O cards - require access to more than one PCI memory region in a driver. - - - Each mapping has its own directory in sysfs, the first mapping - appears as /sys/class/uio/uioX/maps/map0/. - Subsequent mappings create directories map1/, - map2/, and so on. These directories will only - appear if the size of the mapping is not 0. - - - Each mapX/ directory contains four read-only files - that show attributes of the memory: - - - - - name: A string identifier for this mapping. This - is optional, the string can be empty. Drivers can set this to make it - easier for userspace to find the correct mapping. - - - - - addr: The address of memory that can be mapped. - - - - - size: The size, in bytes, of the memory - pointed to by addr. - - - - - offset: The offset, in bytes, that has to be - added to the pointer returned by mmap() to get - to the actual device memory. This is important if the device's memory - is not page aligned. Remember that pointers returned by - mmap() are always page aligned, so it is good - style to always add this offset. - - - - - - From userspace, the different mappings are distinguished by adjusting - the offset parameter of the - mmap() call. To map the memory of mapping N, you - have to use N times the page size as your offset: - - -offset = N * getpagesize(); - - - - Sometimes there is hardware with memory-like regions that can not be - mapped with the technique described here, but there are still ways to - access them from userspace. The most common example are x86 ioports. - On x86 systems, userspace can access these ioports using - ioperm(), iopl(), - inb(), outb(), and similar - functions. - - - Since these ioport regions can not be mapped, they will not appear under - /sys/class/uio/uioX/maps/ like the normal memory - described above. Without information about the port regions a hardware - has to offer, it becomes difficult for the userspace part of the - driver to find out which ports belong to which UIO device. - - - To address this situation, the new directory - /sys/class/uio/uioX/portio/ was added. It only - exists if the driver wants to pass information about one or more port - regions to userspace. If that is the case, subdirectories named - port0, port1, and so on, - will appear underneath - /sys/class/uio/uioX/portio/. - - - Each portX/ directory contains four read-only - files that show name, start, size, and type of the port region: - - - - - name: A string identifier for this port region. - The string is optional and can be empty. Drivers can set it to make it - easier for userspace to find a certain port region. - - - - - start: The first port of this region. - - - - - size: The number of ports in this region. - - - - - porttype: A string describing the type of port. - - - - - - - - - - -Writing your own kernel module - - Please have a look at uio_cif.c as an - example. The following paragraphs explain the different - sections of this file. - - - -struct uio_info - - This structure tells the framework the details of your driver, - Some of the members are required, others are optional. - - - - -const char *name: Required. The name of your driver as -it will appear in sysfs. I recommend using the name of your module for this. - - - -const char *version: Required. This string appears in -/sys/class/uio/uioX/version. - - - -struct uio_mem mem[ MAX_UIO_MAPS ]: Required if you -have memory that can be mapped with mmap(). For each -mapping you need to fill one of the uio_mem structures. -See the description below for details. - - - -struct uio_port port[ MAX_UIO_PORTS_REGIONS ]: Required -if you want to pass information about ioports to userspace. For each port -region you need to fill one of the uio_port structures. -See the description below for details. - - - -long irq: Required. If your hardware generates an -interrupt, it's your modules task to determine the irq number during -initialization. If you don't have a hardware generated interrupt but -want to trigger the interrupt handler in some other way, set -irq to UIO_IRQ_CUSTOM. -If you had no interrupt at all, you could set -irq to UIO_IRQ_NONE, though this -rarely makes sense. - - - -unsigned long irq_flags: Required if you've set -irq to a hardware interrupt number. The flags given -here will be used in the call to request_irq(). - - - -int (*mmap)(struct uio_info *info, struct vm_area_struct -*vma): Optional. If you need a special -mmap() function, you can set it here. If this -pointer is not NULL, your mmap() will be called -instead of the built-in one. - - - -int (*open)(struct uio_info *info, struct inode *inode) -: Optional. You might want to have your own -open(), e.g. to enable interrupts only when your -device is actually used. - - - -int (*release)(struct uio_info *info, struct inode *inode) -: Optional. If you define your own -open(), you will probably also want a custom -release() function. - - - -int (*irqcontrol)(struct uio_info *info, s32 irq_on) -: Optional. If you need to be able to enable or disable -interrupts from userspace by writing to /dev/uioX, -you can implement this function. The parameter irq_on -will be 0 to disable interrupts and 1 to enable them. - - - - -Usually, your device will have one or more memory regions that can be mapped -to user space. For each region, you have to set up a -struct uio_mem in the mem[] array. -Here's a description of the fields of struct uio_mem: - - - - -const char *name: Optional. Set this to help identify -the memory region, it will show up in the corresponding sysfs node. - - - -int memtype: Required if the mapping is used. Set this to -UIO_MEM_PHYS if you you have physical memory on your -card to be mapped. Use UIO_MEM_LOGICAL for logical -memory (e.g. allocated with kmalloc()). There's also -UIO_MEM_VIRTUAL for virtual memory. - - - -phys_addr_t addr: Required if the mapping is used. -Fill in the address of your memory block. This address is the one that -appears in sysfs. - - - -resource_size_t size: Fill in the size of the -memory block that addr points to. If size -is zero, the mapping is considered unused. Note that you -must initialize size with zero for -all unused mappings. - - - -void *internal_addr: If you have to access this memory -region from within your kernel module, you will want to map it internally by -using something like ioremap(). Addresses -returned by this function cannot be mapped to user space, so you must not -store it in addr. Use internal_addr -instead to remember such an address. - - - - -Please do not touch the map element of -struct uio_mem! It is used by the UIO framework -to set up sysfs files for this mapping. Simply leave it alone. - - - -Sometimes, your device can have one or more port regions which can not be -mapped to userspace. But if there are other possibilities for userspace to -access these ports, it makes sense to make information about the ports -available in sysfs. For each region, you have to set up a -struct uio_port in the port[] array. -Here's a description of the fields of struct uio_port: - - - - -char *porttype: Required. Set this to one of the predefined -constants. Use UIO_PORT_X86 for the ioports found in x86 -architectures. - - - -unsigned long start: Required if the port region is used. -Fill in the number of the first port of this region. - - - -unsigned long size: Fill in the number of ports in this -region. If size is zero, the region is considered unused. -Note that you must initialize size -with zero for all unused regions. - - - - -Please do not touch the portio element of -struct uio_port! It is used internally by the UIO -framework to set up sysfs files for this region. Simply leave it alone. - - - - - -Adding an interrupt handler - - What you need to do in your interrupt handler depends on your - hardware and on how you want to handle it. You should try to - keep the amount of code in your kernel interrupt handler low. - If your hardware requires no action that you - have to perform after each interrupt, - then your handler can be empty. If, on the other - hand, your hardware needs some action to - be performed after each interrupt, then you - must do it in your kernel module. Note - that you cannot rely on the userspace part of your driver. Your - userspace program can terminate at any time, possibly leaving - your hardware in a state where proper interrupt handling is - still required. - - - - There might also be applications where you want to read data - from your hardware at each interrupt and buffer it in a piece - of kernel memory you've allocated for that purpose. With this - technique you could avoid loss of data if your userspace - program misses an interrupt. - - - - A note on shared interrupts: Your driver should support - interrupt sharing whenever this is possible. It is possible if - and only if your driver can detect whether your hardware has - triggered the interrupt or not. This is usually done by looking - at an interrupt status register. If your driver sees that the - IRQ bit is actually set, it will perform its actions, and the - handler returns IRQ_HANDLED. If the driver detects that it was - not your hardware that caused the interrupt, it will do nothing - and return IRQ_NONE, allowing the kernel to call the next - possible interrupt handler. - - - - If you decide not to support shared interrupts, your card - won't work in computers with no free interrupts. As this - frequently happens on the PC platform, you can save yourself a - lot of trouble by supporting interrupt sharing. - - - - -Using uio_pdrv for platform devices - - In many cases, UIO drivers for platform devices can be handled in a - generic way. In the same place where you define your - struct platform_device, you simply also implement - your interrupt handler and fill your - struct uio_info. A pointer to this - struct uio_info is then used as - platform_data for your platform device. - - - You also need to set up an array of struct resource - containing addresses and sizes of your memory mappings. This - information is passed to the driver using the - .resource and .num_resources - elements of struct platform_device. - - - You now have to set the .name element of - struct platform_device to - "uio_pdrv" to use the generic UIO platform device - driver. This driver will fill the mem[] array - according to the resources given, and register the device. - - - The advantage of this approach is that you only have to edit a file - you need to edit anyway. You do not have to create an extra driver. - - - - -Using uio_pdrv_genirq for platform devices - - Especially in embedded devices, you frequently find chips where the - irq pin is tied to its own dedicated interrupt line. In such cases, - where you can be really sure the interrupt is not shared, we can take - the concept of uio_pdrv one step further and use a - generic interrupt handler. That's what - uio_pdrv_genirq does. - - - The setup for this driver is the same as described above for - uio_pdrv, except that you do not implement an - interrupt handler. The .handler element of - struct uio_info must remain - NULL. The .irq_flags element - must not contain IRQF_SHARED. - - - You will set the .name element of - struct platform_device to - "uio_pdrv_genirq" to use this driver. - - - The generic interrupt handler of uio_pdrv_genirq - will simply disable the interrupt line using - disable_irq_nosync(). After doing its work, - userspace can reenable the interrupt by writing 0x00000001 to the UIO - device file. The driver already implements an - irq_control() to make this possible, you must not - implement your own. - - - Using uio_pdrv_genirq not only saves a few lines of - interrupt handler code. You also do not need to know anything about - the chip's internal registers to create the kernel part of the driver. - All you need to know is the irq number of the pin the chip is - connected to. - - - - -Using uio_dmem_genirq for platform devices - - In addition to statically allocated memory ranges, they may also be - a desire to use dynamically allocated regions in a user space driver. - In particular, being able to access memory made available through the - dma-mapping API, may be particularly useful. The - uio_dmem_genirq driver provides a way to accomplish - this. - - - This driver is used in a similar manner to the - "uio_pdrv_genirq" driver with respect to interrupt - configuration and handling. - - - Set the .name element of - struct platform_device to - "uio_dmem_genirq" to use this driver. - - - When using this driver, fill in the .platform_data - element of struct platform_device, which is of type - struct uio_dmem_genirq_pdata and which contains the - following elements: - - - struct uio_info uioinfo: The same - structure used as the uio_pdrv_genirq platform - data - unsigned int *dynamic_region_sizes: - Pointer to list of sizes of dynamic memory regions to be mapped into - user space. - - unsigned int num_dynamic_regions: - Number of elements in dynamic_region_sizes array. - - - - The dynamic regions defined in the platform data will be appended to - the mem[] array after the platform device - resources, which implies that the total number of static and dynamic - memory regions cannot exceed MAX_UIO_MAPS. - - - The dynamic memory regions will be allocated when the UIO device file, - /dev/uioX is opened. - Similar to static memory resources, the memory region information for - dynamic regions is then visible via sysfs at - /sys/class/uio/uioX/maps/mapY/*. - The dynamic memory regions will be freed when the UIO device file is - closed. When no processes are holding the device file open, the address - returned to userspace is ~0. - - - - - - - -Writing a driver in userspace - - Once you have a working kernel module for your hardware, you can - write the userspace part of your driver. You don't need any special - libraries, your driver can be written in any reasonable language, - you can use floating point numbers and so on. In short, you can - use all the tools and libraries you'd normally use for writing a - userspace application. - - - -Getting information about your UIO device - - Information about all UIO devices is available in sysfs. The - first thing you should do in your driver is check - name and version to - make sure your talking to the right device and that its kernel - driver has the version you expect. - - - You should also make sure that the memory mapping you need - exists and has the size you expect. - - - There is a tool called lsuio that lists - UIO devices and their attributes. It is available here: - - - - http://www.osadl.org/projects/downloads/UIO/user/ - - - With lsuio you can quickly check if your - kernel module is loaded and which attributes it exports. - Have a look at the manpage for details. - - - The source code of lsuio can serve as an - example for getting information about an UIO device. - The file uio_helper.c contains a lot of - functions you could use in your userspace driver code. - - - - -mmap() device memory - - After you made sure you've got the right device with the - memory mappings you need, all you have to do is to call - mmap() to map the device's memory - to userspace. - - - The parameter offset of the - mmap() call has a special meaning - for UIO devices: It is used to select which mapping of - your device you want to map. To map the memory of - mapping N, you have to use N times the page size as - your offset: - - - offset = N * getpagesize(); - - - N starts from zero, so if you've got only one memory - range to map, set offset = 0. - A drawback of this technique is that memory is always - mapped beginning with its start address. - - - - -Waiting for interrupts - - After you successfully mapped your devices memory, you - can access it like an ordinary array. Usually, you will - perform some initialization. After that, your hardware - starts working and will generate an interrupt as soon - as it's finished, has some data available, or needs your - attention because an error occurred. - - - /dev/uioX is a read-only file. A - read() will always block until an - interrupt occurs. There is only one legal value for the - count parameter of - read(), and that is the size of a - signed 32 bit integer (4). Any other value for - count causes read() - to fail. The signed 32 bit integer read is the interrupt - count of your device. If the value is one more than the value - you read the last time, everything is OK. If the difference - is greater than one, you missed interrupts. - - - You can also use select() on - /dev/uioX. - - - - - - - -Generic PCI UIO driver - - The generic driver is a kernel module named uio_pci_generic. - It can work with any device compliant to PCI 2.3 (circa 2002) and - any compliant PCI Express device. Using this, you only need to - write the userspace driver, removing the need to write - a hardware-specific kernel module. - - - -Making the driver recognize the device - -Since the driver does not declare any device ids, it will not get loaded -automatically and will not automatically bind to any devices, you must load it -and allocate id to the driver yourself. For example: - - modprobe uio_pci_generic - echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id - - - -If there already is a hardware specific kernel driver for your device, the -generic driver still won't bind to it, in this case if you want to use the -generic driver (why would you?) you'll have to manually unbind the hardware -specific driver and bind the generic driver, like this: - - echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind - echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind - - - -You can verify that the device has been bound to the driver -by looking for it in sysfs, for example like the following: - - ls -l /sys/bus/pci/devices/0000:00:19.0/driver - -Which if successful should print - - .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic - -Note that the generic driver will not bind to old PCI 2.2 devices. -If binding the device failed, run the following command: - - dmesg - -and look in the output for failure reasons - - - - -Things to know about uio_pci_generic - -Interrupts are handled using the Interrupt Disable bit in the PCI command -register and Interrupt Status bit in the PCI status register. All devices -compliant to PCI 2.3 (circa 2002) and all compliant PCI Express devices should -support these bits. uio_pci_generic detects this support, and won't bind to -devices which do not support the Interrupt Disable Bit in the command register. - - -On each interrupt, uio_pci_generic sets the Interrupt Disable bit. -This prevents the device from generating further interrupts -until the bit is cleared. The userspace driver should clear this -bit before blocking and waiting for more interrupts. - - - -Writing userspace driver using uio_pci_generic - -Userspace driver can use pci sysfs interface, or the -libpci libray that wraps it, to talk to the device and to -re-enable interrupts by writing to the command register. - - - -Example code using uio_pci_generic - -Here is some sample userspace driver code using uio_pci_generic: - -#include <stdlib.h> -#include <stdio.h> -#include <unistd.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <fcntl.h> -#include <errno.h> - -int main() -{ - int uiofd; - int configfd; - int err; - int i; - unsigned icount; - unsigned char command_high; - - uiofd = open("/dev/uio0", O_RDONLY); - if (uiofd < 0) { - perror("uio open:"); - return errno; - } - configfd = open("/sys/class/uio/uio0/device/config", O_RDWR); - if (configfd < 0) { - perror("config open:"); - return errno; - } - - /* Read and cache command value */ - err = pread(configfd, &command_high, 1, 5); - if (err != 1) { - perror("command config read:"); - return errno; - } - command_high &= ~0x4; - - for(i = 0;; ++i) { - /* Print out a message, for debugging. */ - if (i == 0) - fprintf(stderr, "Started uio test driver.\n"); - else - fprintf(stderr, "Interrupts: %d\n", icount); - - /****************************************/ - /* Here we got an interrupt from the - device. Do something to it. */ - /****************************************/ - - /* Re-enable interrupts. */ - err = pwrite(configfd, &command_high, 1, 5); - if (err != 1) { - perror("config write:"); - break; - } - - /* Wait for next interrupt. */ - err = read(uiofd, &icount, 4); - if (err != 4) { - perror("uio read:"); - break; - } - - } - return errno; -} - - - - - - - - - -Generic Hyper-V UIO driver - - The generic driver is a kernel module named uio_hv_generic. - It supports devices on the Hyper-V VMBus similar to uio_pci_generic - on PCI bus. - - - -Making the driver recognize the device - -Since the driver does not declare any device GUID's, it will not get loaded -automatically and will not automatically bind to any devices, you must load it -and allocate id to the driver yourself. For example, to use the network device -GUID: - - modprobe uio_hv_generic - echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" > /sys/bus/vmbus/drivers/uio_hv_generic/new_id - - - -If there already is a hardware specific kernel driver for the device, the -generic driver still won't bind to it, in this case if you want to use the -generic driver (why would you?) you'll have to manually unbind the hardware -specific driver and bind the generic driver, like this: - - echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 > /sys/bus/vmbus/drivers/hv_netvsc/unbind - echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 > /sys/bus/vmbus/drivers/uio_hv_generic/bind - - - -You can verify that the device has been bound to the driver -by looking for it in sysfs, for example like the following: - - ls -l /sys/bus/vmbus/devices/vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3/driver - -Which if successful should print - - .../vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3/driver -> ../../../bus/vmbus/drivers/uio_hv_generic - - - - - -Things to know about uio_hv_generic - -On each interrupt, uio_hv_generic sets the Interrupt Disable bit. -This prevents the device from generating further interrupts -until the bit is cleared. The userspace driver should clear this -bit before blocking and waiting for more interrupts. - - - - - -Further information - - - - OSADL homepage. - - - - Linutronix homepage. - - - - - -- cgit v1.2.3