Linux drivers generalities - Revision history

JulienB: /* Where should I copy modules ? */

2009-06-11T20:42:58Z

‎Where should I copy modules ?

JulienB: /* How to use them */

2009-06-11T20:42:09Z

‎How to use them

JulienB at 08:41, 12 December 2008

2008-12-12T08:41:57Z

JulienB at 08:02, 8 December 2008

2008-12-08T08:02:36Z

JulienB: /* What */

2008-10-19T09:45:54Z

‎What

JulienB: be more accurate

2008-10-18T07:40:06Z

be more accurate

JulienB: creation

2008-10-17T20:46:14Z

creation

New page

This page summarizes all the important things to know when talking about Linux drivers in general.

==What==
Linux drivers are the piece of code running inside the kernel itself that are assigned to a specific peripheral driving.
They can exist in 2 forms:
* they can be statically linked to the kernel image. In that case we refer to static drivers
* or they can be compiled as loadable modules (the famous .ko files)

When compiled as module (<M> in linux menuconfig) they can be dynamically loaded at runtime, when necessary. For example if you need to load the FPGA at a particular time you can do a:
# modprobe fpga_loader
or
# insmod /lib/modules/drivers/armadeus/fpga/fpga_loader.ko

modprobe knows where to find the correspondig .ko file and find all its dependancies thanks to the ''/etc/modules.dep'' file

@@ Line 21: / Line 21: @@
 ==Where should I copy modules ?==
 ''modprobe'' knows where to find the corresponding .ko file and find all its dependencies thanks to the ''/lib/modules/2.6.2x/modules.dep'' file. So If you compile new drivers as module and copy them on your board "manually" (ie TFTP or NFS), don't forget to update ''/lib/modules/2.6.2x/modules.dep'' too. On your Host this file can be found in ''buildroot/project_build_armvxx/apfxx/root/lib/modules/2.6.2x/modules.dep''.
-All modules are located in ''/lib/modules/drivers/'' subdirectories on your target and ''buildroot/project_build_armvxx/apfxx/root/lib/modules/drivers'' on your Host.
+All modules are located in ''/lib/modules/2.6.xx/drivers/'' subdirectories on your target and ''buildroot/project_build_armvxx/apfxx/root/lib/modules/drivers'' on your Host.
 [[Category:Linux drivers]]

@@ Line 8: / Line 8: @@
 ==How to use them==
-When compiled as "static" (<*> in Linux menuconfig) they are integrated in the Linux image (''buildroot/binaries/apfxx/linux-kernel-2.6.xx-arm.bin''), so when you reflash your kernel, the driver are immediately available. But if you don't use them, the consume some place in memory (RAM).
+When compiled as "static" ('''<*>''', in Linux menuconfig) they are integrated in the Linux image (''buildroot/binaries/apfxx/linux-kernel-2.6.xx-arm.bin''), so when you reflash your kernel, the driver are immediately available. But if you don't use them, they consume some place in memory (RAM).
-When compiled as "module" (<M> in Linux menuconfig) they can be dynamically loaded at runtime, when necessary. For example if you need to load the FPGA at a particular time you can do a:
+When compiled as "module" ('''<M>''', in Linux menuconfig) they can be dynamically loaded at runtime, when necessary. For example if you need to load the FPGA at a particular time you can do a:
   # modprobe fpga_loader
 or
-  # insmod /lib/modules/drivers/armadeus/fpga/fpga_loader.ko
+<pre class="apf">
 ==Where should I copy modules ?==

← Older revision		Revision as of 08:41, 12 December 2008
Line 18:		Line 18:
	''modprobe'' knows where to find the corresponding .ko file and find all its dependencies thanks to the ''/lib/modules/2.6.2x/modules.dep'' file. So If you compile new drivers as module and copy them on your board "manually" (ie TFTP or NFS), don't forget to update ''/lib/modules/2.6.2x/modules.dep'' too. On your Host this file can be found in ''buildroot/project_build_armvxx/apfxx/root/lib/modules/2.6.2x/modules.dep''.		''modprobe'' knows where to find the corresponding .ko file and find all its dependencies thanks to the ''/lib/modules/2.6.2x/modules.dep'' file. So If you compile new drivers as module and copy them on your board "manually" (ie TFTP or NFS), don't forget to update ''/lib/modules/2.6.2x/modules.dep'' too. On your Host this file can be found in ''buildroot/project_build_armvxx/apfxx/root/lib/modules/2.6.2x/modules.dep''.
	All modules are located in ''/lib/modules/drivers/'' subdirectories on your target and ''buildroot/project_build_armvxx/apfxx/root/lib/modules/drivers'' on your Host.		All modules are located in ''/lib/modules/drivers/'' subdirectories on your target and ''buildroot/project_build_armvxx/apfxx/root/lib/modules/drivers'' on your Host.
		+
		+	[[Category:Linux drivers]]

@@ Line 8: / Line 8: @@
 ==How to use them==
-When compiled as "static" (<*> in Linux menuconfig) they are integrated in the Linux image (''buildroot/binaries/armadeus/linux-kernel-2.6.xx-arm.bin''), so when you reflash your kernel, the driver are immediately available. But if you don't use them, the consume some place in memory (RAM).
+When compiled as "static" (<*> in Linux menuconfig) they are integrated in the Linux image (''buildroot/binaries/apfxx/linux-kernel-2.6.xx-arm.bin''), so when you reflash your kernel, the driver are immediately available. But if you don't use them, the consume some place in memory (RAM).
 When compiled as "module" (<M> in Linux menuconfig) they can be dynamically loaded at runtime, when necessary. For example if you need to load the FPGA at a particular time you can do a:
@@ Line 16: / Line 16: @@
 ==Where should I copy modules ?==
-''modprobe'' knows where to find the corresponding .ko file and find all its dependencies thanks to the ''/lib/modules/2.6.2x/modules.dep'' file. So If you compile new drivers as module and copy them on your board "manually" (ie TFTP or NFS), don't forget to update ''/lib/modules/2.6.2x/modules.dep'' too. On your Host this file can be found in ''buildroot/project_build_arm/armadeus/root/lib/modules/2.6.2x/modules.dep''.
+''modprobe'' knows where to find the corresponding .ko file and find all its dependencies thanks to the ''/lib/modules/2.6.2x/modules.dep'' file. So If you compile new drivers as module and copy them on your board "manually" (ie TFTP or NFS), don't forget to update ''/lib/modules/2.6.2x/modules.dep'' too. On your Host this file can be found in ''buildroot/project_build_armvxx/apfxx/root/lib/modules/2.6.2x/modules.dep''.
-All modules are located in ''/lib/modules/drivers/'' subdirectories on your target and ''buildroot/project_build_arm/armadeus/root/lib/modules/drivers'' on your Host.
+All modules are located in ''/lib/modules/drivers/'' subdirectories on your target and ''buildroot/project_build_armvxx/apfxx/root/lib/modules/drivers'' on your Host.

@@ Line 1: / Line 1: @@
 This page summarizes all the important things to know when talking about Linux drivers in general.
-==What==
+==What are they ?==
 Linux drivers are the piece of code running inside the kernel itself that are assigned to a specific peripheral driving.
 They can exist in 2 forms:
@@ Line 7: / Line 7: @@
 * or they can be compiled as loadable modules (the famous .ko files)
 When compiled as "static" (<*> in Linux menuconfig) they are integrated in the Linux image (''buildroot/binaries/armadeus/linux-kernel-2.6.xx-arm.bin''), so when you reflash your kernel, the driver are immediately available. But if you don't use them, the consume some place in memory (RAM).
@@ Line 14: / Line 15: @@
   # insmod /lib/modules/drivers/armadeus/fpga/fpga_loader.ko
 ''modprobe'' knows where to find the corresponding .ko file and find all its dependencies thanks to the ''/lib/modules/2.6.2x/modules.dep'' file. So If you compile new drivers as module and copy them on your board "manually" (ie TFTP or NFS), don't forget to update ''/lib/modules/2.6.2x/modules.dep'' too. On your Host this file can be found in ''buildroot/project_build_arm/armadeus/root/lib/modules/2.6.2x/modules.dep''.