Change the BUG_ON() condition in brcmnand_send_cmd() which checks for
the interrupt status "controller ready" bit to a WARN_ON.
There is no good reason to kill the system when this condition occur
because we could have systems which listed the NAND controller as
available (e.g: from Device Tree), but the NAND chip could be
malfunctioning and not responding.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
In case of error, the function dma_request_chan() returns ERR_PTR() and
never returns NULL. The NULL test in the return value check should be
replaced with IS_ERR().
Fixes: aa7abd312c ('mtd: nand: omap2: Support parsing dma channel
information from DT')
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Pull NAND changes from Boris Brezillon:
"""
This pull request contains only one notable change:
* Addition of the MTK NAND controller driver
And a bunch of specific NAND driver improvements/fixes. Here are the
changes that are worth mentioning:
* A few fixes/improvements for the xway NAND controller driver
* A few fixes for the sunxi NAND controller driver
* Support for DMA in the sunxi NAND driver
* Support for the sunxi NAND controller IP embedded in A23/A33 SoCs
* Addition for bitflips detection in erased pages to the brcmnand driver
* Support for new brcmnand IPs
* Update of the OMAP-GPMC binding to support DMA channel description
"""
commit c9711ec525 ("mtd: nand: omap: Clean up device tree support")
removes the check for the old elm phandle binding.
Add it again to keep backward compatibility.
Fixes: commit c9711ec525 ("mtd: nand: omap: Clean up device tree support")
Signed-off-by: Teresa Remmet <t.remmet@phytec.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This patch enables IFC NAND support on ARM layerscape platform.
It fixes the dependency to enable NAND. The include files are being modified
to ensure complilation for both PowerPC and ARM architectures.
Signed-off-by: Raghav Dogra <raghav.dogra@nxp.com>
Acked-by: Scott Wood <oss@buserror.net>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
I moved the sanity check on ecc->size before the allocation so that we
don't leak memory on error.
Fixes: 05af074a4b73 ('mtd: nand: sunxi: check ecc->size values')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Instead of using IO_ADDR_W and IO_ADDR_R use an own pointer to the NAND
controller memory area.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This driver needs a special write_buf and read_buf function, because we
have to read from a specific address to tell the controller this is a
read from the nand controller.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Extract the functions to read and write to the register of the NAND
flash controller.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
The external Bus Unit (EBU) can control different flash devices, but
these NAND flash commands have to be atomic and should not be
interrupted in between. Lock the EBU from the beginning of the command
till the end by moving the lock to the chip select.
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
nand_scan() already resets the NAND flash chip, this driver does not
have to call it manually. The xway_reset_chip() functions does the same
as the normal NAND reset function. The waiting for the NAND_WAIT_WR_C
is done in xway_cmd_ctrl().
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
The ->cmd_ctrl() function is adjusting the ->IO_ADDR_W value depending
on the command type each time NAND_CTRL_CHANGE is passed. This is not
only useless but can lead to an ->IO_ADDR_W corruption.
Get rid of this logic and rely on the NAND_CLE and NAND_ALE flags to
deduce the iomem address to write the cmd argument to.
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Instead of hacking this into the plat_nand driver just make this a
normal nand driver.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This adds some register documentation which should make it easier to
understand how this controller works. In addition it makes now use of
BIT() macro and adds some more defines.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Implement ecc->write_subpage() to prevent core code from assigning this
hook to nand_write_subpage_hwecc(). This default implementation tries
to call ecc->hwctl() which in our case is NULL, thus leading to a NULL
pointer dereference.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Verify that the ecc->size value is either 512 or 1024 bytes.
This should always be the case if this field was assigned to the
nand->ecc_step_size_ds value, but can be wrong when the user overloaded
this value with the nand-ecc-step-size DT property.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Switching to 1k ECC blocks when possible provides better resistance against
concentrated bitflips. Say you have those two configurations:
1/ 16bits/512bytes
2/ 32bits/1024bytes
Both of them require the same amount of ECC bytes (only true for this
specific engine), but the second config allows you to correct the case
where most of your bitflips are concentrated in a single 512bytes portion.
This fact makes the 1k ECC block size more advantageous than the 512bytes
one.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
The column address passed to the RNDOUT operation was missing the page
size offset.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes: 614049a8d9 ("mtd: nand: sunxi: add support for DMA assisted operations")
In case of error, the function dmaengine_prep_slave_sg() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Fixes: 614049a8d9 ("mtd: nand: sunxi: add support for DMA assisted operations")
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This change provides a fix for controller bug where nand
controller could have a possible sticky error after a PIO
followed by a DMA read. The fix retries a read if we see
a uncorr_ecc after read to detect such sticky errors.
The fix applies to only controller version 7.0 and 7.1.
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Check for erased page bitflips in a page. And if well within
threshold return data as all 0xff. Apply sw check for controller
version < 7.2. Controller vesion >= 7.2 has hw support.
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
I got device with ESMT (Elite Semiconductor Memory Technology Inc)
F59L1G81MA flash that was detected as:
[ 0.852034] nand: device found, Manufacturer ID: 0xc8, Chip ID: 0xd1
[ 0.858402] nand: Unknown NAND 128MiB 3,3V 8-bit
[ 0.863031] nand: 128MiB, SLC, page size: 2048, OOB size: 64
According to the F59L1G81MA datasheet (and Read Id documentation) C8h is
a "Maker Code" which should mean ESMT. Add it to fix above "Unknown".
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
The sunxi NAND controller is able to pipeline ECC operations only when
operated in DMA mode, which improves a lot NAND throughput while keeping
CPU usage low.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
The 7.2 controller differs in a few area compared to its predecssor (7.1):
- NAND scrambler, which we are not using just yet
- higher ECC levels (up to 120 bits) per 1KB data blocks, also not supported yet
- up to 128B OOB
This patch adds the necessary code to support such a controller
generation and updates the Device Tree binding.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Kamal Dasu <kdasu.kdev@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Switch from dma_request_channel to allow passing dma channel
information from DT rather than hardcoding a value.
Also provide a handle to the GPMC's dev so it can be used to parse the DMA
channel information within the GPMC's DT node.
Performance Numbers via mtd_speedtest now that EDMA based prefetch works:
AM335x Performance numbers:
DMA
CPULOAD Write: 54% Read: 35%
page write speed -23% (vs non dma)
page read speed -35% (vs non dma)
NO DMA (prefetch-polled)
CPULOAD Write: 98% Read: 98%
AM437x Performance numbers:
DMA
CPU LOAD Write: 56% Read: 36%
page write speed -16% (vs non dma)
page read speed -22% (vs non dma)
NO DMA (prefetch-polled)
CPULOAD Write: 93% Read: 93%
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Pull MTD fixes from Brian Norris:
"We've already noticed a few flaws in the MTD work for v4.7-rc1:
- The Atmel folks got ahead of themselves on trying to support their
latest hardware and were working off incorrect documentation. Fix
up the NAND driver to get this correct.
- Fix up device tree example documentation to use the latest
recommendations for describing NAND ECC algorithms"
* tag 'for-linus-20160527' of git://git.infradead.org/linux-mtd:
Documentation: dt: mtd: drop "soft_bch" from example
Revert "mtd: atmel_nand: Support variable RB_EDGE interrupts"
This reverts commit 5ddc7bd43c ("mtd: atmel_nand: Support variable
RB_EDGE interrupts")
Because for current SoCs, the RB_EDGE3(i.e. bit 27) of HSMC_SR
register does not exist, the RB_EDGE0 (i.e. bit 24) is the ready/busy
line edge status bit. It is a datasheet bug.
Cc: <stable@vger.kernel.org>
Fixes: commit 5ddc7bd43c ("mtd: atmel_nand: Support variable RB_EDGE interrupts")
Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Pull MTD updates from Brian Norris:
"First cycle with Boris as NAND maintainer! Many (most) bullets stolen
from him.
Generic:
- Migrated NAND LED trigger to be a generic MTD trigger
NAND:
- Introduction of the "ECC algorithm" concept, to avoid overloading
the ECC mode field too much more
- Replaced the nand_ecclayout infrastructure with something a little
more flexible (finally!) and future proof
- Rework of the OMAP GPMC and NAND drivers; the TI folks pulled some
of this into their own tree as well
- Prepare the sunxi NAND driver to receive DMA support
- Handle bitflips in erased pages on GPMI revisions that do not
support this in hardware.
SPI NOR:
- Start using the spi_flash_read() API for SPI drivers that support
it (i.e., SPI drivers with special memory-mapped flash modes)
And other small scattered improvments"
* tag 'for-linus-20160523' of git://git.infradead.org/linux-mtd: (155 commits)
mtd: spi-nor: support GigaDevice gd25lq64c
mtd: nand_bch: fix spelling of "probably"
mtd: brcmnand: respect ECC algorithm set by NAND subsystem
gpmi-nand: Handle ECC Errors in erased pages
Documentation: devicetree: deprecate "soft_bch" nand-ecc-mode value
mtd: nand: add support for "nand-ecc-algo" DT property
mtd: mtd: drop NAND_ECC_SOFT_BCH enum value
mtd: drop support for NAND_ECC_SOFT_BCH as "soft_bch" mapping
mtd: nand: read ECC algorithm from the new field
mtd: nand: fsmc: validate ECC setup by checking algorithm directly
mtd: nand: set ECC algorithm to Hamming on fallback
staging: mt29f_spinand: set ECC algorithm explicitly
CRIS v32: nand: set ECC algorithm explicitly
mtd: nand: atmel: set ECC algorithm explicitly
mtd: nand: davinci: set ECC algorithm explicitly
mtd: nand: bf5xx: set ECC algorithm explicitly
mtd: nand: omap2: Fix high memory dma prefetch transfer
mtd: nand: omap2: Start dma request before enabling prefetch
mtd: nandsim: add __init attribute
mtd: nand: move of_get_nand_xxx() helpers into nand_base.c
...
Pull LED updates from Jacek Anaszewski:
"In this merge cycle we had an interaction with MTD subsystem, that
included converting drivers/mtd/nand/nand_base.c to use newly
introduced MTD (NAND/NOR) LED trigger instead of implementing it on
its own.
Related MTD patches are intended to be merged through the LED tree,
before MTD tree is merged, since further MTD development is based on
those modifications.
Summary:
LEDs:
- Introduce a kernel panic LED trigger
- Introduce a MTD (NAND/NOR) trigger
- led-tca6507: silence an uninitialized variable warning
- ledtrig-ide-disk: Move ide_blink_delay to ledtrig_ide_activity()
- leds-ss4200: Add depend on x86 arch
- leds-ss4200: add DMI data for FSC SCALEO Home Server
- leds-triggers: Allow to switch the trigger to "panic" on a kernel panic
- devicetree: leds: Introduce "panic-indicator" optional property
- leds-gpio: Support the "panic-indicator" firmware property
MTD:
- Uninline mtd_write_oob and move it to mtdcore.c
- Remove the "nand-disk" LED trigger
- Hook I/O activity to the MTD LED trigger"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
leds: gpio: Support the "panic-indicator" firmware property
devicetree: leds: Introduce "panic-indicator" optional property
leds: triggers: Allow to switch the trigger to "panic" on a kernel panic
leds: ss4200: add DMI data for FSC SCALEO Home Server
leds: ss4200: Add depend on x86 arch
leds: ledtrig-ide-disk: Move ide_blink_delay to ledtrig_ide_activity()
leds: tca6507: silence an uninitialized variable warning
mtd: Hook I/O activity to the MTD LED trigger
mtd: nand: Remove the "nand-disk" LED trigger
leds: trigger: Introduce a MTD (NAND/NOR) trigger
mtd: Uninline mtd_write_oob and move it to mtdcore.c
leds: trigger: Introduce a kernel panic LED trigger
Updates from Boris Brezillon:
This pull request contains the following infrastructure changes:
* introduction of the ECC algo concept to extend the ECC mode one
* replacement of the nand_ecclayout infrastructure by something more
future-proof.
* addition of an mtd-activity led trigger to replace the nand-activity
one
And a bunch of specific NAND driver improvements/fixes. Here are the
changes that are worth mentioning:
* rework of the OMAP GPMC and NAND drivers
* prepare the sunxi NAND driver to receive DMA support
* handle bitflips in erased pages on GPMI revisions that do not support
this in hardware.
* tag 'nand/for-4.7' of github.com:linux-nand/linux: (152 commits)
mtd: brcmnand: respect ECC algorithm set by NAND subsystem
gpmi-nand: Handle ECC Errors in erased pages
Documentation: devicetree: deprecate "soft_bch" nand-ecc-mode value
mtd: nand: add support for "nand-ecc-algo" DT property
mtd: mtd: drop NAND_ECC_SOFT_BCH enum value
mtd: drop support for NAND_ECC_SOFT_BCH as "soft_bch" mapping
mtd: nand: read ECC algorithm from the new field
mtd: nand: fsmc: validate ECC setup by checking algorithm directly
mtd: nand: set ECC algorithm to Hamming on fallback
staging: mt29f_spinand: set ECC algorithm explicitly
CRIS v32: nand: set ECC algorithm explicitly
mtd: nand: atmel: set ECC algorithm explicitly
mtd: nand: davinci: set ECC algorithm explicitly
mtd: nand: bf5xx: set ECC algorithm explicitly
mtd: nand: omap2: Fix high memory dma prefetch transfer
mtd: nand: omap2: Start dma request before enabling prefetch
mtd: nandsim: add __init attribute
mtd: nand: move of_get_nand_xxx() helpers into nand_base.c
mtd: nand: sh_flctl: rely on generic DT parsing done in nand_scan_ident()
mtd: nand: mxc: rely on generic DT parsing done in nand_scan_ident()
...
This is more obvious than guessing based on ECC strength. It allows
using NAND on devices with BCH-1 (e.g. D-Link DIR-885L).
This maintains DT backward compatibility by defaulting to Hamming if a
1-bit ECC algorithm is specified without a corresponding algorithm
selection. i.e., to use BCH-1, you must specify:
nand-ecc-strength = <1>;
nand-ecc-step-size = <512>;
nand-ecc-algo = "bch";
Also adds a check to ensure we haven't allowed someone to get by with SW
ECC. If we want to support SW ECC, we need to refactor some other pieces
of this driver.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Tested-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
ECC is only calculated for written pages. As erased pages are not
actively written the ECC is always invalid. For this purpose the
Hardware BCH unit is able to check for erased pages and does not raise
an ECC error in this case. This behaviour can be influenced using the
BCH_MODE register which sets the number of allowed bitflips in an erased
page. Unfortunately the unit is not capable of fixing the bitflips in
memory.
To avoid complete software checks for erased pages, we can simply check
buffers with uncorrectable ECC errors because we know that any erased
page with errors is uncorrectable by the BCH unit.
This patch adds the generic nand_check_erased_ecc_chunk() to gpmi-nand
to correct erased pages. To have the valid data in the buffer before
using them, this patch moves the read_page_swap_end() call before the
ECC status checking for-loop.
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
[Squashed patches by Stefan and Boris to check ECC area]
Tested-by: Stefan Christ <s.christ@phytec.de>
Acked-by: Han xu <han.xu@nxp.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
So far it was only possible to specify ECC algorithm using "soft" and
"soft_bch" values of nand-ecc-mode prop. There wasn't a way to specify
it for a hardware ECC mode.
Now that we have independent field in NAND subsystem for storing info
about ECC algorithm we may also add support for this new DT property.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This value should not be part of nand_ecc_modes_t as it specifies
algorithm not a mode. We successfully managed to introduce new "algo"
field which is respected now.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
There isn't any difference between handling NAND_ECC_SOFT and
NAND_ECC_SOFT_BCH now. What matters is the new field called "algo".
Please note we're keeping backward DT compatibility. We are still
treating "soft_bch" value as the one setting Hamming algorithm, it's
just handled in of_get_nand_ecc_algo now.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Now we have all drivers properly setting this new field we can start
using it. For a very short period of time we should support both values:
NAND_ECC_SOFT and NAND_ECC_SOFT_BCH treating them the same. It's because
of_get_nand_ecc_mode may still be setting NAND_ECC_SOFT_BCH.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
NAND core sets ECC algorithm in algo field now and it should be
preferred over the mode field. This also prepares driver for dropping
NAND_ECC_SOFT_BCH.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This is part of process deprecating NAND_ECC_SOFT_BCH (and switching to
enum nand_ecc_algo).
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This is part of process deprecating NAND_ECC_SOFT_BCH (and switching to
enum nand_ecc_algo).
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This is part of process deprecating NAND_ECC_SOFT_BCH (and switching to
enum nand_ecc_algo).
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This is part of process deprecating NAND_ECC_SOFT_BCH (and switching to
enum nand_ecc_algo).
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Based on DMA documentation and testing using high memory buffer when doing
dma transfers can lead to various issues including kernel panics.
To workaround this simply use cpu copy.
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
The prefetch engine sends a dma request once a FIFO threshold has
been met. No other requests are received until the previous request
is handled.
Starting a dma transfer (dma_async_issue_pending) results in any
previous event for the dma channel to be cleared. Therefore, starting
the prefetch engine before initiating the dma transfer may result in
the prefetch triggering a dma request but instead of it being handled
it can end up being cleared. This will result in a hang since the code
will continue to wait for the dma request to complete.
By initiating the dma request before enabling the prefetch engine this
race condition is avoided and no dma request are missed/cleared.
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Add __init attribute on functions that are only called from other __init
functions and that are not inlined, at least with gcc version 4.8.4 on an
x86 machine with allyesconfig. Currently, the functions are put in the
.text.unlikely segment. Declaring them as __init will cause them to be
put in the .init.text and to disappear after initialization.
The result of objdump -x on the functions before the change is as follows:
000000000000059a l F .text.unlikely 0000000000000239 alloc_device
000000000000034e l F .text.unlikely 000000000000002e get_partition_name
00000000000007d3 l F .text.unlikely 00000000000005da init_nandsim
And after the change it is as follows:
0000000000000029 l F .init.text 0000000000000234 alloc_device
0000000000000000 l F .init.text 0000000000000029 get_partition_name
000000000000025d l F .init.text 00000000000005d5 init_nandsim
Done with the help of Coccinelle. The semantic patch checks for local
static non-init functions that are called from an __init function and are
not called from any other function.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Now that all drivers go through nand_set_flash_node() to parse the generic
NAND properties, we can move all of_get_nand_xxx() helpers in to
nand_base.c, make them static and remove of_mtd.c and of_mtd.h.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
The core now takes care of parsing generic DT properties in
nand_scan_ident() when nand_set_flash_node() has been called.
Rely on this initialization instead of calling of_get_nand_xxx()
manually.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
