MFC r344505-r344507, r344523, r344525-r344526, r344529, r344606-r344612,
r344614-r344616, r344681, r344684-r344686, r344728, r344733-r344734, r344981

A large set of changes that collectively moderni

MFC r344505-r344507, r344523, r344525-r344526, r344529, r344606-r344612,
r344614-r344616, r344681, r344684-r344686, r344728, r344733-r344734, r344981

A large set of changes that collectively modernize the at45d and mx25l
(DataFlash and SpiFlash) drivers, add FDT support, and add geom_flashmap and
geom_label support to them.

r344505:
Add a functional detach() implementation to make module unloading possible.

r344506:
Add support for probing/attaching on FDT-based systems.

r344507:
Switch to using config_intrhook_oneshot(). That allows the error handling
in the delayed attach to use early returns, which allows reducing the level
of indentation. So all in all, what looks like a lot of changes is really
no change in behavior, mostly just moving whitespace around.

r344523:
Include the jedec "extended device information string" in the criteria used
to match a chip to our table of metadata describing the chips. At least one
new DataFlash chip has a 3-byte jedec ID identical to its predecessors and
differs only in the extended info, and it has different metadata requiring a
unique entry in the table. This paves the way for supporting such chips.

The metadata table now includes two new fields, extmask and extid. The two
bytes of extended info obtained from the chip are ANDed with extmask then
compared to extid, so it's possible to use only a subset of the extended
info in the matching.

We now always read 6 bytes of jedec ID info. Most chips don't return any
extended info, and the values read back for those two bytes may be
indeterminate, but such chips have extmask and extid values of 0x0000 in the
table, so the extid effectively doesn't participate in the matching on those
chips and it doesn't matter what they return in the extended info bytes.

r344525:
Add a metadata entry for the AT45DB641E chip. This chip has the same 3-byte
jedec ID as its older cousin the AT45DB642D, but uses a different page size.
The only way to distinguish between the two chips is that the 2D chip has
0 bytes of extended ID info and the new 1E has 1 byte of extended ID. The
actual value of the extended ID byte is all zeroes. In other words, it's
the presence of the extended info that identifies this chip. (Presumably
a future upgrade might define non-zero values for the extended ID byte.)

r344526:
Resolve a name conflict when both SpiFlash and DataFlash devices are present.

Both SpiFlash (mx25l) and DataFlash (at45d) drivers create a disk device
with a name of /dev/flash/spiN where N is the driver's unit number. If
both types of devices are present in the same system, this creates a fatal
conflict that prevents attachment of whichever device attaches second
(because mx25l0 and at45d0 both try to create a spi0).

This gives each type of device a unique name (mx25lN or at45dN respectively)
and also adds an alias of spiN for compatibility. When both device types
appear in the same system, only the first to attach gets the spiN alias.
When the second device attaches there is a non-fatal warning that the alias
can't be created, but both devices are still accessible via their primary
names (and there is no need for the spiN name to work for backwards
compatibility on such a system, because it has never been possible to use
the spiN names when both devices exist).

r344529:
Fix a paste-o that broke the build on all arches.

r344606:
Add support for geom_flashmap by providing a getattr() for "SPI:device".

r344607:
Compile fdt_slicer and geom_flashmap when the at45d device is included.

r344608:
Update a comment to reflect reality; no functional changes.

r344609:
Make it possible to load fdt_slicer as a module (unloading works too fwiw).

r344610:
Add manpages for at45d(4) and mx25l(4).

r344611:
Add a module dependency on fdt_slicer.

r344612:
Add a module dependency on fdt_slicer. Also, move the PNP_INFO to its more
usual location, down near the DRIVER_MODULE() stuff.

r344614:
Rename some functions and variables to have shorter names, which allows
unwrapping multiple lines of code. Also, convert some short multiline
comments into single-line comments. Change old-school FALSE to false.

All in all, no functional changes, it's just more compact and readable.

r344615:
Child nodes with a compatible property are not slices, according to the
devicetree/bindings/mtd/partitions.txt document, so just ignore them.

r344616:
Add support to fdt_slicer for the new style partition data documented in
devicetree/bindings/mtd/partition.txt.

In the old style, all the children of the device node which did not have a
compatible property were the partitions. In the new style, there is a child
node of the device which has a compatible string of "fixed-partitions", and
its children are the individual partitions.

Also, support the read-only property by setting the corresponding slice flag.

r344681:
Build fdt support modules on systems that use fdt data.

kern.opts.mk sets make var OPT_FDT to a non-empty value if platform.h
contains OPT_FDT.

r344684:
Undo accidental part of r344681.

I think I must have accidentally mouse-click pasted while scrolling and
didn't notice it.

Reported by: jhibbits@

r344685:
Add required header file to SRCS.

r344686:
Add another required header file.

For some reason this seems to be required on aarch64, but I can build armv7
from clean without needing this in the list. (The file does get included,
so the mystery is why armv7 works.)

r344728:
Bugfix: use a dummy buffer for the inactive side of a transfer.

This is especially important for writes. SPI is inherently a bidirectional
bus; you receive data (even if it's garbage) while writing. We should not
receive that data into the same buffer we're writing to the device.

When reading it doesn't matter what we send to the device, but using the
dummy buffer for that as well is pleasingly symmetrical.

r344733:
Add some comments. Give #define'd names to some scattered numbers. Change
some #define'd names to be more descriptive. When reporting a post-write
compare failure, report the page number, not the byte address of the page.
The latter is the only functional change, it makes the number match the
words of the error message.

r344734:
Allow the sector size of the disk device to be configured using hints or
FDT data. The sector size must be a multiple of the device's page size.
If not configured, use the historical default of the device page size.

Setting the disk sector size to 512 or 4096 allows a variety of standard
filesystems to be used on the device. Of course you wouldn't want to be
writing frequently to a SPI flash chip like it was a disk drive, but for
data that gets written once (or rarely) and read often, using a standard
filesystem is a nice convenient thing.

r344981:
Give the mx25l device sole ownership of the name /dev/flash/spi* instead of
trying to use disk_add_alias() to make spi* an alias for mx25l*. It turns
out disk_add_alias() works for partitions, but not slices, and that's hard
to fix.

This change is, in effect, a partial revert of r344526.

The mips world relies on the existence of flashmap names formatted as
/dev/flash/spi0s.name, whereas pretty much nothing relies on at45d devices
using the /dev/spi* names (because until recently the at45d driver didn't
even work reliably). So this change makes mx25l devices the sole owner of
the /dev/flash/spi* namespace, which actually makes some sense because it is
a SpiFlash(tm) device, so flash/spi isn't a horrible name.

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