Relationship between Linux Device Drivers and the entire hardware System 1. device classification and features the hardware of a computer system consists of CPU, memory, and peripherals. With the development of the IC (Integratedcircuit) manufacturing process, the current chip integration is getting higher and higher, often integrated into the CPU memory and... relationship between Linux Device Drivers and
the device here:
Result = register_chrdev (254, "test", test_fops );
(2) set test. copy c to the/uclinux/linux/drivers/char directory, and mem in the/uclinux/linux/drivers/char directory. in c, add the following code to the int chr_dev_init () function:
# Ifdef CONFIG_TESTDRIVE
Init_test ();
# Endif
(3) add the following code to Makefile in the/uclinux/linux/
I. INPUT SUBSYSTEM architectureThe input subsystem is drivers by the drive layer , inputs the subsystem core input core, event processing layer events handler composition. An input event that is sent to the system via the input device such as mouse movement, keyboard keys press inferior via device driver->input core (handler->event function)->event handler->user space to the application by reaching the user space in the order. An output event that is
Using a connection pool for the data source may cause role-based security damage. The support for trusted connections and trusted contexts on the IBMInformix server allows flexible reuse of connections, granting controlled permissions to the middle layer, and enhancing user responsibility in layer-3 applications without compromising database security, all of these improve the system performance.
Using a connection pool for the data source may cause role-based security damage. Support for trusted
Notebook model
Mechanical Revolution (Mechrevo) deep sea Titan X6ti-s (black gold) 15.6 inch
CPU model
I5-7300hq
Memory
8G
HDD capacity
128SSD+1T Mechanical HDD
Graphics
GeForce GTX 1050
Memory capacity
4G
How do I buy a laptop for Linux?Installing Linux drivers on notebooks is mainly on the GPU and Nic. The network card chooses Intel or Broadc
formats :
_io (magic number, radix);
_ior (magic number, cardinality, variable type)
_iow (magic number, cardinality, variable type)
_IOWR (magic number, cardinality, variable type)
Magic number (magic number)The magic number range is 0~255. Typically, the English characters "a" ~ "Z" or "a" ~ "Z" are represented. The device driver obtains the magic number from the command passed in, and then compares it to the number of demons it handles, and if the same is handled, t
following formats :
_io (magic number, radix);
_ior (magic number, cardinality, variable type)
_iow (magic number, cardinality, variable type)
_IOWR (magic number, cardinality, variable type)
Magic Numbers (magic number)The magic number range is 0~255. Typically, the English characters "a" ~ "Z" or "a" ~ "Z" are represented. The device driver obtains the magic number from the command passed in, and then compares it to the number of demons it handles, and if the same is
Sndrv_dev_jack ((__force snd_device_type_t) 0x1009)
#define Sndrv_dev_lowlevel ((__force snd_device_type_t) 0x2000)
In general, we are more concerned with both the PCM and control devices.Three. Driver-driven code file structureIn the Linux2.6 code tree, the ALSA code file structure is as follows:Sound/core/oss/seq/ioctl32/include/drivers/i2c/synth/emux/pci/(Cards)/isa/(Cards)/arm/ppc/sparc/usb/pcmcia/(cards)/oss/soc/codecs
Core This direc
holds the processor context snapshot before the processor enters the interrupt code
The interrupt processing routine should return a value that indicates whether an interrupt was actually handled, and if the processing routine finds that its device does need to be processed, it should return irq_handled, otherwise the return value should be Irq_none
Enable and disable interrupts
sometimes device drivers must bloc
Using asynchronous notifications in device drivers can make access to the device accessible to the application by the driver when it is accessible. Therefore, applications that use nonblocking I/O do not need to poll the device for access, and blocking access can be superseded by asynchronous notifications like "break". Asynchronous notifications are similar to the concept of "interrupts" on hardware, and the more accurate term is "signal-driven async
1.1 Linux device driver classification
Linux device drivers occupy a large proportion of the Linux kernel source code, and the length of the source code is increasing, mainly the increase of the driver. During the continuous upgrade of Linux kernel, the structure of driver is still relatively stable. In the 2.0.xx to 2.2.xx changes, the driver's writing has made some changes, but from 2.0.xx Drive to 2.2.xx porting only a small amount of work. The de
This example is for Android up-Reading Exploration (vol. 1): The Demo sample program included with the HAL and Driver Development book. are now pasted out for inspection.Terminal operations, commands that may be used:Insmond Word_count.kolsmod | grep Word_count to see if the driver was successfully installed Rmmod WORD_COUNTDMESG | grep word_cout | Tail-n 2 View log information with Linux driver output Cat/var/log/syslong | grep Word_count | Tail-n 2modinfo Word_count.ko View driver informationD
Skb_release_data function has 0xc4 so large, and oops occurs at 0x74 place. So let's take a look at where the Skb_release_data starts:#grep Skb_release_data./system.mapC0282AF4 T Skb_release_dataSo we know that when the system error occurs, the program pointer is c0282af4+0x74=c0282b68(2) Then use GDB to view the GDB./vmlinux (executed under the Linux directory) and enter debug mode.gdb$ b *0xc0282b68Breakpoint 1 at 0xc0282b68:file NET/CORE/SKBUFF.C, line312This is to tell us in which file, in
will have to also." ”3, see example Drive, Linux kernel driver, generally have a relatively simple example code, specifically, see the first step of the TXT document. With this simple example code, we further clarify how the drive works.4, good, ready to work to complete, here should formally start. Write it yourself? No, or secretly lazy, online to find ready-made, there is just your chip driver, really lucky, direct use, of course, often can not be used directly, to debug under the next line.
code under default and clean starts with the TAB key.Third, compile the Globalvar modulePut the previous globalvar.c file and the makefile file in the same folder, I was placed in the Globalvar folder I created, go to the Globalvar folder, open the terminal, and then log in root permissions, enter the make command compile module. Four, write the test program of the Globalvar module, name it test_globalvar.c, the source code is as follows: #include Compile the test file in the terminal input Di
this driver"10. When the driver installation succeeds, you can see that the output of the debug message "Hello from Pnpdriver", the output statement you can find in the DriverEntry function of your source code.11. To end the debugging, remember to click "Debug"-"End debugging".12. The next time you continue debugging without restarting the virtual machine, you can use the built-in pipeline directly. Hit a breakpoint below to try.13. Commissioning situation:Problem Collection1. There are no VISU
, depending on the break flags to determine whether the send is completed or accepted.static irqreturn_t dm9000_interrupt (int irq, void *dev_id){if (Int_status ISR_PRS)-accepts data interrupts.Dm9000_rx (Dev);if (Int_status isr_pts)Dm9000_tx_done (dev, db);}static void Dm9000_tx_done (struct net_device *dev, board_info_t * db){Netif_wake_queue (Dev); --wake-up waiting queue}2.5 Data AcceptanceFor data acceptance, the data is actually read from the media buffer and then submitted to the upper
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