Differential D3457 Diff 8120 sys/modules/ioat/README

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sys/modules/ioat/README

	FreeBSD Crystal Beach DMA driver			FreeBSD Crystal Beach DMA driver
	==========================================			==========================================
	* Driver is named ioat(4)			* Driver is named ioat(4)
	* Driver only supports copy and null operations. Null operations may be used			* Driver only supports copy and null operations. Null operations may be used
	to insert descriptors which only trigger an interrupt.			to insert descriptors which only trigger an interrupt.
	* Note that copy operation takes bus addresses as parameters, not virtual			* Note that copy operation takes bus addresses as parameters, not virtual
	addresses.			addresses.
	* Copies larger than max transfer size (1MB) are not supported, and will			* Copies larger than max transfer size (1MB) are not supported. Future
	panic the system explicitly. Future versions will likely support this by			versions will likely support this by breaking up the transfer into smaller
	breaking up the transfer into smaller sizes.			sizes.
	* There are 8 CB-DMA channels per CPU package. Each channel will be			* There are 8 CB-DMA channels per CPU package. Each channel is represented by
	represented by a struct ioat_softc data structure.			a struct ioat_softc.
	* There is an ioat_test.c module in the driver, and an ioatcontrol.c			* There is an ioat_test.c module in the driver which exposes a simple device at
	application that can be used to both test the driver as well as understand			/dev/ioat_test. The presense of the test device may be controlled with the
	how to interface with the driver. App uses a /dev/ioat_test device node			hw.ioat.enable_ioat_test tunable. (The default is off.) There is an
	to send IOCTLs which will cause the driver to:			ioatcontrol.c application in tools/tools/ioat
				that can be used to test the driver. It sends IOCTLs which will cause the
				driver to:
	* run a loop a number of times as requested by the app			* run a loop a number of times as requested by the app
	* each loop will allocate two chunks of memory, write data patterns			* each loop will allocate two chunks of memory, write data patterns
	to each, submit a DMA request to copy one buffer to the other,			to each, submit a DMA request to copy one buffer to the other,
	and compare the contents in the callback, reporting an error if one			and compare the contents in the callback, reporting an error if one
	is found			is found
	The ioat_test.c module needs to be enabled in the driver Makefile to use it.			To build the test program from tools/tools/ioat: make ioatcontrol
	To build the app from /sys/modules/ioat directory: make ioatcontrol			To run it: ./ioatcontrol <channel #> <num_loops>
	To run the app: ./ioatcontrol <channel #> <num_loops>			* Debug verbosity is 0 by default (only critical errors) but can be increased
	* Debug prints are enabled by defining IOAT_LOGGING, which is currently the			by doing one of the following:
	default in the Makefile. Verbosity is 0 by default (only critical errors)
	but can be increased by doing one of the following:
	* from command line, before driver is loaded:			* from command line, before driver is loaded:
	kenv hw.ioat.debug_level=3			kenv hw.ioat.debug_level=3
	* add the following to /boot/loader.conf			* add the following to /boot/loader.conf
	hw.ioat.debug_level=3			hw.ioat.debug_level=3
				* at runtime: sysctl hw.ioat.debug_level=3