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Test Your Knowledge in Computers #190
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In computer science, a data type is an attribute of data which informs the compiler or interpreter how the programmer intends to use the data.
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pci_request_region_exclusive(9) [centos man page]

PCI_REQUEST_REGION_E(9) 					Hardware Interfaces					   PCI_REQUEST_REGION_E(9)

NAME
pci_request_region_exclusive - Reserved PCI I/O and memory resource SYNOPSIS
int pci_request_region_exclusive(struct pci_dev * pdev, int bar, const char * res_name); ARGUMENTS
pdev PCI device whose resources are to be reserved bar BAR to be reserved res_name Name to be associated with resource. DESCRIPTION
Mark the PCI region associated with PCI device pdev BR bar as being reserved by owner res_name. Do not access any address inside the PCI regions unless this call returns successfully. Returns 0 on success, or EBUSY on error. A warning message is also printed on failure. The key difference that _exclusive makes it that userspace is explicitly not allowed to map the resource via /dev/mem or sysfs. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 PCI_REQUEST_REGION_E(9)

Check Out this Related Man Page

PROTO(4)						   BSD Kernel Interfaces Manual 						  PROTO(4)

NAME
proto -- Driver for prototyping and H/W diagnostics SYNOPSIS
To compile this driver into the kernel, place the following line in your kernel configuration file: device proto Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5): proto_load="YES" DESCRIPTION
The proto device driver attaches to PCI devices when no other device drivers are present and creates device special files for all resources associated with the device. The driver itself has no knowledge of the device it attaches to. Programs can open these device special files and perform register-level reads and writes. As such, the proto device driver is nothing but a conduit or gateway between user space pro- grams and the hardware device. Examples for why this is useful include hardware diagnostics and prototyping. In both these use cases, it is far more convenient to develop and run the logic in user space. Especially hardware diagnostics requires a somewhat user-friendly interface and adequate reporting. Nei- ther is done easily as kernel code. FILES
All device special files corresponding to a PCI device are located under /dev/proto/pci<d>:<b>:<s>:<f> with pci<d>:<b>:<s>:<f> representing the location of the PCI device in the PCI hierarchy. A location includes: <d> The PCI domain number <b> The PCI bus number <s> The PCI slot or device number <f> The PCI function number Every PCI device has a device special file called pcicfg. This device special file gives access to the PCI configuration space. For each valid base address register (BAR), a device special file is created that contains the BAR offset and the resource type. A resource type can be either io or mem representing I/O port or memory mapped I/O space (resp.) EXAMPLES
A single function PCI device in domain 0, on bus 1, in slot 2 and having a single memory mapped I/O region will have the following device special files: /dev/proto/pci0:1:2:0/10.mem /dev/proto/pci0:1:2:0/pcicfg AUTHORS
The proto device driver and this manual page were written by Marcel Moolenaar <marcel@xcllnt.net>. SECURITY CONSIDERATIONS
Because programs have direct access to the hardware, the proto driver is inherently insecure. It is not advisable to use this driver on a production machine. MISSING FUNCTIONALITY
The proto driver does not yet support interrupts. Since interrupts cannot be handled by the driver itself, they must be converted into sig- nals and delivered to the program that has registered for interrupts. In order to test the transmission or reception of data, some means of doing direct memory access (DMA) by the device must be possible. This too must be under the control of the program. The details of how a program can set up and initiate DMA still need to be fleshed out. Support for non-PCI devices has not been implemented yet. BSD
April 29, 2014 BSD

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