Add dmaengine based NVIDIA's Tegra APB DMA driver.
This driver support the slave mode of data transfer from
peripheral to memory and vice versa.
The driver supports for the cyclic and non-cyclic mode
of data transfer.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
Add support for the SA-11x0 DMA driver, which replaces the private
API version in arch/arm/mach-sa1100/dma.c.
We model this as a set of virtual DMA channels, one for each request
signal, and assign the virtual DMA channel to a physical DMA channel
when there is work to be done. This allows DMA users to claim their
channels, and hold them while not in use, without affecting the
availability of the physical channels.
Another advantage over this approach, compared to the private version,
is that a channel can be reconfigured on the fly without having to
release and re-request it - which for the IrDA driver, allows us to
use DMA for SIR mode transmit without eating up three physical
channels. As IrDA is half-duplex, we actually only need one physical
channel, and this architecture allows us to achieve that.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Jassi Brar <jaswinder.singh@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Rongjun Ying <rongjun.ying@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
[fixed direction enums and cyclic api based on changes
already merged]
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
The ep93xx DMA controller has 10 independent memory to peripheral (M2P)
channels, and 2 dedicated memory to memory (M2M) channels. M2M channels can
also be used by SPI and IDE to perform DMA transfers to/from their memory
mapped FIFOs.
This driver supports both M2P and M2M channels with DMA_SLAVE, DMA_CYCLIC and
DMA_MEMCPY (M2M only) capabilities.
Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx: (66 commits)
avr32: at32ap700x: fix typo in DMA master configuration
dmaengine/dmatest: Pass timeout via module params
dma: let IMX_DMA depend on IMX_HAVE_DMA_V1 instead of an explicit list of SoCs
fsldma: make halt behave nicely on all supported controllers
fsldma: reduce locking during descriptor cleanup
fsldma: support async_tx dependencies and automatic unmapping
fsldma: fix controller lockups
fsldma: minor codingstyle and consistency fixes
fsldma: improve link descriptor debugging
fsldma: use channel name in printk output
fsldma: move related helper functions near each other
dmatest: fix automatic buffer unmap type
drivers, pch_dma: Fix warning when CONFIG_PM=n.
dmaengine/dw_dmac fix: use readl & writel instead of __raw_readl & __raw_writel
avr32: at32ap700x: Specify DMA Flow Controller, Src and Dst msize
dw_dmac: Setting Default Burst length for transfers as 16.
dw_dmac: Allow src/dst msize & flow controller to be configured at runtime
dw_dmac: Changing type of src_master and dest_master to u8.
dw_dmac: Pass Channel Priority from platform_data
dw_dmac: Pass Channel Allocation Order from platform_data
...
Replace EXTRA_CFLAGS with ccflags-y.
Signed-off-by: matt mooney <mfm@muteddisk.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This patch adds dma support for Freescale MXS-based SoC i.MX23/28,
including apbh-dma and apbx-dma.
* apbh-dma and apbx-dma are supported in the driver as two mxs-dma
instances.
* apbh-dma is different between mx23 and mx28, hardware version
register is used to differentiate.
* mxs-dma supports pio function besides data transfer. The driver
uses dma_data_direction DMA_NONE to identify the pio mode, and
steals sgl and sg_len to get pio words and numbers from clients.
* mxs dmaengine has some very specific features, like sense function
and the special NAND support (nand_lock, nand_wait4ready). These
are too specific to implemented in generic dmaengine driver.
* The driver refers to imx-sdma and only a single descriptor is
statically assigned to each channel.
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Use the ccflag-y flag instead of EXTRA_CFLAGS because EXTRA_CFLAGS is
deprecated and should now be switched. According to (documentation/kbuild/makefiles.txt).
Signed-off-by: Tracey Dent <tdent48227@gmail.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This driver is currently implemented as a user to the old i.MX
DMA API. This allows us to convert each user of the old API to
the dmaengine API one by one. Once this is done the old DMA
driver can be merged into the i.MX dmaengine driver.
V2: remove some debug leftovers and unused variables
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This patch adds support for the Freescale i.MX SDMA engine.
The SDMA engine is a scatter/gather DMA engine which is implemented
as a seperate coprocessor. SDMA needs its own firmware which is
requested using the standard request_firmware mechanism. The firmware
has different entry points for each peripheral type, so drivers
have to pass the peripheral type to the DMA engine which in turn
picks the correct firmware entry point from a table contained in
the firmware image itself.
The original Freescale code also supports support for transfering
data to the internal SRAM which needs different entry points to
the firmware. Support for this is currently not implemented. Also,
support for the ASRC (asymmetric sample rate converter) is skipped.
I took a very simple approach to implement dmaengine support. Only
a single descriptor is statically assigned to a each channel. This
means that transfers can't be queued up but only a single transfer
is in progress. This simplifies implementation a lot and is sufficient
for the usual device/memory transfers.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Linus Walleij <linus.ml.walleij@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This creates a DMAengine driver for the ARM PL080/PL081 PrimeCells
based on the implementation earlier submitted by Peter Pearse.
This is working like a charm for memcpy and slave DMA to the PL011
PrimeCell on the PB11MPCore.
This DMA controller is used in mostly unmodified form in the ARM
RealView and Versatile platforms, in the ST-Ericsson Nomadik, and
in the ST SPEAr platform.
It has been converted to use the header from the Samsung PL080
derivate instead of its own defintions. The Samsungs have a custom
driver in their mach-* folders though, atleast we can share the
register definitions.
Cc: Peter Pearse <peter.pearse@arm.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Alessandro Rubini <rubini@unipv.it>
Acked-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
[GFP_KERNEL to GFP_NOWAIT in pl08x_prep_dma_memcpy]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Topcliff PCH is the platform controller hub that is going to
be used in Intel's upcoming general embedded platforms. This
adds the driver for Topcliff PCH DMA controller. The DMA
channels are strictly for device to host or host to device
transfers and cannot be used for generic memcpy.
Signed-off-by: Yong Wang <yong.y.wang@intel.com>
[kill GFP_ATOMIC, kill __raw_{read|write}l, locking fixlet]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This patch add DMA drivers for DMA controllers in Langwell chipset
of Intel(R) Moorestown platform and DMA controllers in Penwell of
Intel(R) Medfield platfrom
This patch adds support for Moorestown DMAC1 and DMAC2 controllers.
It also add support for Medfiled GP DMA and DMAC1 controllers.
These controllers supports memory to peripheral and peripheral to
memory transfers. It support only single block transfers.
This driver is based on Kernel DMA engine
Anyone who wishes to use this controller should use DMA engine APIs
This controller exposes DMA_SLAVE capabilities and notifies the client drivers
of DMA transaction completion
Config option required to be enabled CONFIG_INTEL_MID_DMAC=y
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Add DMA Engine API driver for the PL330 DMAC.
This driver is supposed to be reusable by various
platforms that have one or more PL330 DMACs.
Atm, DMA_SLAVE and DMA_MEMCPY capabilities have been
implemented.
Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Reviewed-by: Linus Walleij <linus.walleij@stericsson.com>
[dan.j.williams@intel.com: missing slab.h and ->device_control() fixups]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This is a straightforward driver for the ST-Ericsson DMA40 DMA
controller found in U8500, implemented akin to the existing
COH 901 318 driver.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Srinidh Kasagar <srinidhi.kasagar@stericsson.com>
Cc: STEricsson_nomadik_linux@list.st.com
Cc: Alessandro Rubini <rubini@unipv.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Adds the support for the DMA engine withing the timberdale FPGA.
The DMA channels are strict device to host, or host to device
and can not be used for generic memcpy.
Signed-off-by: Richard Röjfors <richard.rojfors@pelagicore.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Adds initial version of MPC512x DMA driver.
Only memory to memory transfers are currenly supported.
Signed-off-by: Piotr Ziecik <kosmo@semihalf.com>
Signed-off-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: John Rigby <jcrigby@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This adds Kconfig options for DEBUG and VERBOSE_DEBUG to the DMA
engine subsystem, I got tired of editing the Makefile manually
each time I want to debug things in here, modelled this on the
debug switches for other subsystems and works like a charm when
working on our DMA engines.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This patch adds new version of the PPC440SPe ADMA driver.
Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This patch adds support for the ST-Ericsson COH 901 318 DMA block,
found in the U300 series platforms. It registers a DMA slave for
device I/O and also a memcpy slave for memcpy.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This supported all DMA channels, and it was tested in SH7722,
SH7780, SH7785 and SH7763.
This can not use with SH DMA API.
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
Reviewed-by: Matt Fleming <matt@console-pimps.org>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
When first created the ioat driver was the only inhabitant of
drivers/dma/. Now, it is the only multi-file (more than a .c and a .h)
driver in the directory. Moving it to an ioat/ subdirectory allows the
naming convention to be cleaned up, and allows for future splitting of
the source files by hardware version (v1, v2, and v3).
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This AHB DMA Controller (aka HDMA or DMAC on AT91 systems) is availlable on
at91sam9rl chip. It will be used on other products in the future.
This first release covers only the memory-to-memory tranfer type. This is the
only tranfer type supported by this chip. On other products, it will be used
also for peripheral DMA transfer (slave API support to come).
I used dmatest client without problem in different configurations to test it.
Full documentation for this controller can be found in the SAM9RL datasheet:
http://www.atmel.com/dyn/products/product_card.asp?part_id=4243
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This patch adds support for the integrated DMAC of the TXx9 family.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
i.MX3x SoCs contain an Image Processing Unit, consisting of a Control
Module (CM), Display Interface (DI), Synchronous Display Controller (SDC),
Asynchronous Display Controller (ADC), Image Converter (IC), Post-Filter
(PF), Camera Sensor Interface (CSI), and an Image DMA Controller (IDMAC).
CM contains, among other blocks, an Interrupt Generator (IG) and a Clock
and Reset Control Unit (CRCU). This driver serves IDMAC and IG. They are
supported over dmaengine and irq-chip APIs respectively.
IDMAC is a specialised DMA controller, its DMA channels cannot be used for
general-purpose operations, even though it might be possible to configure
a memory-to-memory channel for memcpy operation. This driver will not work
with generic dmaengine clients, clients, wishing to use it must use
respective wrapper structures, they also must specify which channels they
require, as channels are hard-wired to specific IPU functions.
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This adds a driver for the Synopsys DesignWare DMA controller (aka
DMACA on AVR32 systems.) This DMA controller can be found integrated
on the AT32AP7000 chip and is primarily meant for peripheral DMA
transfer, but can also be used for memory-to-memory transfers.
This patch is based on a driver from David Brownell which was based on
an older version of the DMA Engine framework. It also implements the
proposed extensions to the DMA Engine API for slave DMA operations.
The dmatest client shows no problems, but there may still be room for
improvement performance-wise. DMA slave transfer performance is
definitely "good enough"; reading 100 MiB from an SD card running at ~20
MHz yields ~7.2 MiB/s average transfer rate.
Full documentation for this controller can be found in the Synopsys
DW AHB DMAC Databook:
http://www.synopsys.com/designware/docs/iip/DW_ahb_dmac/latest/doc/dw_ahb_dmac_db.pdf
The controller has lots of implementation options, so it's usually a
good idea to check the data sheet of the chip it's intergrated on as
well. The AT32AP7000 data sheet can be found here:
http://www.atmel.com/dyn/products/datasheets.asp?family_id=682
Changes since v4:
* Use client_count instead of dma_chan_is_in_use()
* Add missing include
* Unmap buffers unless client told us not to
Changes since v3:
* Update to latest DMA engine and DMA slave APIs
* Embed the hw descriptor into the sw descriptor
* Clean up and update MODULE_DESCRIPTION, copyright date, etc.
Changes since v2:
* Dequeue all pending transfers in terminate_all()
* Rename dw_dmac.h -> dw_dmac_regs.h
* Define and use controller-specific dma_slave data
* Fix up a few outdated comments
* Define hardware registers as structs (doesn't generate better
code, unfortunately, but it looks nicer.)
* Get number of channels from platform_data instead of hardcoding it
based on CONFIG_WHATEVER_CPU.
* Give slave clients exclusive access to the channel
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>,
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This client tests DMA memcpy using various lengths and various offsets
into the source and destination buffers. It will initialize both
buffers with a repeatable pattern and verify that the DMA engine copies
the requested region and nothing more. It will also verify that the
bytes aren't swapped around, and that the source buffer isn't modified.
The dmatest module can be configured to test a specific device, a
specific channel. It can also test multiple channels at the same time,
and it can start multiple threads competing for the same channel.
Changes since v2:
* Support testing multiple channels at the same time
* Support testing with multiple threads competing for the same channel
* Use counting test patterns in order to catch byte ordering issues
Changes since v1:
* Remove extra dashes around "help"
* Remove "default n" from Kconfig
* Turn TEST_BUF_SIZE into a module parameter
* Return DMA_NAK instead of DMA_DUP
* Print unhandled events
* Support testing specific channels and devices
* Move to the end of the Makefile
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The XOR engine found in Marvell's SoCs and system controllers
provides XOR and DMA operation, iSCSI CRC32C calculation, memory
initialization, and memory ECC error cleanup operation support.
This driver implements the DMA engine API and supports the following
capabilities:
- memcpy
- xor
- memset
The XOR engine can be used by DMA engine clients implemented in the
kernel, one of those clients is the RAID module. In that case, I
observed 20% improvement in the raid5 write throughput, and 40%
decrease in the CPU utilization when doing array construction, those
results obtained on an 5182 running at 500Mhz.
When enabling the NET DMA client, the performance decreased, so
meanwhile it is recommended to keep this client off.
Signed-off-by: Saeed Bishara <saeed@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The driver implements DMA engine API for Freescale MPC85xx DMA controller,
which could be used by devices in the silicon. The driver supports the
Basic mode of Freescale MPC85xx DMA controller. The MPC85xx processors
supported include MPC8540/60, MPC8555, MPC8548, MPC8641 and so on.
The MPC83xx(MPC8349, MPC8360) are also supported.
[kamalesh@linux.vnet.ibm.com: build fix]
[dan.j.williams@intel.com: merge mm fixes, rebase on async_tx-2.6.25]
Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
Signed-off-by: Ebony Zhu <ebony.zhu@freescale.com>
Acked-by: Kumar Gala <galak@gate.crashing.org>
Cc: Shannon Nelson <shannon.nelson@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Add code to connect to the DCA driver and provide cpu tags for use by
drivers that would like to use Direct Cache Access hints.
[Adrian Bunk] Several Kconfig cleanup items
[Andrew Morten, Chris Leech] Fix for using cpu_physical_id() even when
built for uni-processor
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Split the general PCI startup from the DMA handling code in order to
prepare for adding support for DCA services and future versions of the
ioatdma device.
[Rusty Russell] Removal of __unsafe() usage.
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename the ioatdma.c file in preparation for splitting into multiple files,
which will allow for easier adding new functionality.
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The Intel(R) IOP series of i/o processors integrate an Xscale core with
raid acceleration engines. The capabilities per platform are:
iop219:
(2) copy engines
iop321:
(2) copy engines
(1) xor and block fill engine
iop33x:
(2) copy and crc32c engines
(1) xor, xor zero sum, pq, pq zero sum, and block fill engine
iop34x (iop13xx):
(2) copy, crc32c, xor, xor zero sum, and block fill engines
(1) copy, crc32c, xor, xor zero sum, pq, pq zero sum, and block fill engine
The driver supports the features of the async_tx api:
* asynchronous notification of operation completion
* implicit (interupt triggered) handling of inter-channel transaction
dependencies
The driver adapts to the platform it is running by two methods.
1/ #include <asm/arch/adma.h> which defines the hardware specific
iop_chan_* and iop_desc_* routines as a series of static inline
functions
2/ The private platform data attached to the platform_device defines the
capabilities of the channels
20070626: Callbacks are run in a tasklet. Given the recent discussion on
LKML about killing tasklets in favor of workqueues I did a quick conversion
of the driver. Raid5 resync performance dropped from 50MB/s to 30MB/s, so
the tasklet implementation remains until a generic softirq interface is
available.
Changelog:
* fixed a slot allocation bug in do_iop13xx_adma_xor that caused too few
slots to be requested eventually leading to data corruption
* enabled the slot allocation routine to attempt to free slots before
returning -ENOMEM
* switched the cleanup routine to solely use the software chain and the
status register to determine if a descriptor is complete. This is
necessary to support other IOP engines that do not have status writeback
capability
* make the driver iop generic
* modified the allocation routines to understand allocating a group of
slots for a single operation
* added a null xor initialization operation for the xor only channel on
iop3xx
* support xor operations on buffers larger than the hardware maximum
* split the do_* routines into separate prep, src/dest set, submit stages
* added async_tx support (dependent operations initiation at cleanup time)
* simplified group handling
* added interrupt support (callbacks via tasklets)
* brought the pending depth inline with ioat (i.e. 4 descriptors)
* drop dma mapping methods, suggested by Chris Leech
* don't use inline in C files, Adrian Bunk
* remove static tasklet declarations
* make iop_adma_alloc_slots easier to read and remove chances for a
corrupted descriptor chain
* fix locking bug in iop_adma_alloc_chan_resources, Benjamin Herrenschmidt
* convert capabilities over to dma_cap_mask_t
* fixup sparse warnings
* add descriptor flush before iop_chan_enable
* checkpatch.pl fixes
* gpl v2 only correction
* move set_src, set_dest, submit to async_tx methods
* move group_list and phys to async_tx
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Provides for pinning user space pages in memory, copying to iovecs,
and copying from sk_buffs including fragmented and chained sk_buffs.
Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Provides an API for offloading memory copies to DMA devices
Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Laxman Dewangan