Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
This change allows to just call sdhci_start_slot() in SDHCI drivers
and not to think about which stack handles the operation.
As a side effect, this will also fix MMCCAM with sdhci_acpi driver.
Approved by: imp (mentor)
Differential Revision: https://reviews.freebsd.org/D12471
for embedded slots. Fail in the sdhci(4) initialization for slot type
shared, which is completely unsupported by this driver at the moment. [1]
For Intel eMMC controllers, taking the embedded slot type into account
obsoltes setting SDHCI_QUIRK_ALL_SLOTS_NON_REMOVABLE so remove these quirk
entries.
- Hide the 1.8 V VDD capability when the slot is detected as non-embedded,
as the SDHCI specification explicitly states that 1.8 V VDD is applicable
to embedded slots only. [2]
- Define some easy bits of the SDHCI specification v4.20. [3]
- Don't leak bus_dma(9) resources in failure paths of sdhci_init_slot().
Obtained from: DragonFlyBSD 65704a46 [1], 7ba10b88 [2], 0df14648 [3]
sdhci(4), mmc(4) and mmcsd(4). For the most part, this consists of:
- Correcting and extending the infrastructure for negotiating and
enabling post-DDR52 modes already added as part of r315598. In
fact, HS400ES now should work as well but hasn't been activated
due to lack of corresponding hardware.
- Adding support executing standard SDHCI initial tuning as well
as re-tuning as required for eMMC HS200/HS400 and the fast UHS-I
SD card modes. Currently, corresponding methods are only hooked
up to the ACPI and PCI front-ends of sdhci(4), though. Moreover,
sdhci(4) won't offer any modes requiring (re-)tuning to the MMC/SD
layer in order to not break operations with other sdhci(4) front-
ends. Likewise, sdhci(4) now no longer offers modes requiring the
set_uhs_timing method introduced in r315598 to be implemented/
hooked up (previously, this method was used with DDR52 only, which
in turn is only available with Intel controllers so far, i. e. no
such limitation was necessary before). Similarly for 1.2/1.8 V VCCQ
support and the switch_vccq method.
- Addition of locking to the IOCTL half of mmcsd(4) to prevent races
with detachment and suspension, especially since it's required to
immediately switch away from RPMB partitions again after an access
to these (so re-tuning can take place anew, given that the current
eMMC specification v5.1 doesn't allow tuning commands to be issued
with a RPMB partition selected). Therefore, the existing part_mtx
lock in the mmcsd(4) softc is additionally renamed to disk_mtx in
order to denote that it only refers to the disk(9) half, likewise
for corresponding macros.
On the system where the addition of DDR52 support increased the read
throughput to ~80 MB/s (from ~45 MB/s at high speed), HS200 yields
~154 MB/s and HS400 ~187 MB/s, i. e. performance now has more than
quadrupled compared to pre-r315598.
Also, with the advent of (re-)tuning support, most infrastructure
necessary for SD card UHS-I modes up to SDR104 now is also in place.
Note, though, that the standard SDHCI way of (re-)tuning is special
in several ways, which also is why sending the actual tuning requests
to the device is part of sdhci(4). SDHCI implementations not following
the specification, MMC and non-SDHCI SD card controllers likely will
use a generic implementation in the MMC/SD layer for executing tuning,
which hasn't been written so far, though.
However, in fact this isn't a feature-only change; there are boards
based on Intel Bay Trail where DDR52 is problematic and the suggested
workaround is to use HS200 mode instead. So far exact details are
unknown, however, i. e. whether that's due to a defect in these SoCs
or on the boards.
Moreover, due to the above changes requiring to be aware of possible
MMC siblings in the fast path of mmc(4), corresponding information
now is cached in mmc_softc. As a side-effect, mmc_calculate_clock(),
mmc_delete_cards(), mmc_discover_cards() and mmc_rescan_cards() now
all are guaranteed to operate on the same set of devices as there no
longer is any use of device_get_children(9), which can fail in low
memory situations. Likewise, mmc_calculate_clock() now longer will
trigger a panic due to the latter.
o Fix a bug in the failure reporting of mmcsd_delete(); in case of an
error when the starting block of a previously stored erase request
is used (in order to be able to erase a full erase sector worth of
data), the starting block of the newly supplied bio_pblkno has to be
returned for indicating no progress. Otherwise, upper layers might
be told that a negative number of BIOs have been completed, leading
to a panic.
o Fix 2 bugs on resume:
- Things done in fork1(9) like the acquisition of an SX lock or the
sleepable memory allocation are incompatible with a MTX_DEF taken.
Thus, mmcsd_resume() must not call kproc_create(9), which in turn
uses fork1(9), with the disk_mtx (formerly part_mtx) held.
- In mmc_suspend(), the bus is powered down, which in the typical
case of a device being selected at the time of suspension, causes
the device deselection as part of the bus acquisition by mmc(4) in
mmc_scan() to fail as the bus isn't powered up again before later
in mmc_go_discovery(). Thus, power down with the bus acquired in
mmc_suspend(), which will trigger the deselection up-front.
o Fix a memory leak in mmcsd_ioctl() in case copyin(9) fails. [1]
o Fix missing variable initialization in mmc_switch_status(). [2]
o Fix R1_SWITCH_ERROR detection in mmc_switch_status(). [3]
o Handle the case of device_add_child(9) failing, for example due to
a memory shortage, gracefully in mmc(4) and sdhci(4), including not
leaking memory for the instance variables in case of mmc(4) (which
might or might not fix [4] as the latter problem has been discovered
independently).
o Handle the case of an unknown SD CSD version in mmc_decode_csd_sd()
gracefully instead of calling panic(9).
o Again, check and handle the return values of some additional function
calls in mmc(4) instead of assuming that everything went right or mark
non-fatal errors by casting the return value to void.
o Correct a typo in the Linux IOCTL compatibility; it should have been
MMC_IOC_MULTI_CMD rather than MMC_IOC_CMD_MULTI.
o Now that we are reaching ever faster speeds (more improvement in this
regard is to be expected when adding ADMA support to sdhci(4)), apply
a few micro-optimizations like predicting mmc(4) and sdhci(4) debugging
to be off or caching erase sector and maximum data sizes as well support
of block addressing in mmsd(4) (instead of doing 2 indirections on every
read/write request for determining the maximum data size for example).
Reported by: Coverity
CID: 1372612 [1], 1372624 [2], 1372594 [3], 1007069 [4]
Implement the MMC/SD/SDIO protocol within a CAM framework. CAM's
flexible queueing will make it easier to write non-storage drivers
than the legacy stack. SDIO drivers from both the kernel and as
userland daemons are possible, though much of that functionality will
come later.
Some of the CAM integration isn't complete (there are sleeps in the
device probe state machine, for example), but those minor issues can
be improved in-tree more easily than out of tree and shouldn't gate
progress on other fronts. Appologies to reviews if specific items
have been overlooked.
Submitted by: Ilya Bakulin
Reviewed by: emaste, imp, mav, adrian, ian
Differential Review: https://reviews.freebsd.org/D4761
merge with first commit, various compile hacks.
the commit message; as actually implemented, the intent is to retry
up to 2 ms for controllers to enable bus power.
Noticed by: ian@, rgrimes@
Additional note: Among others, the problem addressed by r320577 is
the APL32 ("Storage Controllers May Not Be Power Gated") erratum.
Hopefully, along with r318282, r320577 works around the remaining
problems seen with Intel Apollo Lake eMMC and SDXC controllers.
Use the SDHCI_CAN_DRIVE_TYPE_A/_C/_D masks to check for Driver Type support,
instead of using the SDHCI_CTRL2_DRIVER_TYPE_A/_C/_D values which are meant
for setting the Driver Type in the HOST_CONTROL2 register.
Approved by: adrian (mentor), jmcneill
Differential Revision: https://reviews.freebsd.org/D10999
controllers that do not support or have broken ACMD12 implementations.
Reviewed by: jmcneill
Obtained from: NetBSD
MFC after: 2 weeks
Sponsored by: Rubicon Communications, LLC (Netgate)
Differential Revision: https://reviews.freebsd.org/D10602
mmc(4). For the most part, this consists of support for:
- Switching the signal voltage (VCCQ) to 1.8 V or (if supported
by the host controller) to 1.2 V,
- setting the UHS mode as appropriate in the SDHCI_HOST_CONTROL2
register,
- setting the power class in the eMMC device according to the
core supply voltage (VCC),
- using different bits for enabling a bus width of 4 and 8 bits
in the the eMMC device at DDR or higher timings respectively,
- arbitrating timings faster than high speed if there actually
are additional devices on the same MMC bus.
Given that support for DDR52 is not denoted by SDHCI capability
registers, availability of that timing is indicated by a new
quirk SDHCI_QUIRK_MMC_DDR52 and only enabled for Intel SDHCI
controllers so far. Generally, what it takes for a sdhci(4)
front-end to enable support for DDR52 is to hook up the bridge
method mmcbr_switch_vccq (which especially for 1.2 V signaling
support is chip/board specific) and the sdhci_set_uhs_timing
sdhci(4) method.
As a side-effect, this change also fixes communication with
some eMMC devices at SDR high speed mode with 52 MHz due to
the signaling voltage and UHS bits in the SDHCI controller no
longer being left in an inappropriate state.
Compared to 52 MHz at SDR high speed which typically yields
~45 MB/s with the eMMC chips tested, throughput goes up to
~80 MB/s at DDR52.
Additionally, this change already adds infrastructure and quite
some code for modes up to HS400ES and SDR104 respectively (I did
not want to add to much stuff at a time, though). Essentially,
what is still missing in order to be able to activate support
for these latter is is support for and handling of (re-)tuning.
o In sdhci(4), add two tunables hw.sdhci.quirk_clear as well as
hw.sdhci.quirk_set, which (when hooked up in the front-end)
allow to set/clear sdhci(4) quirks for debugging and testing
purposes. However, especially for SDHCI controllers on the
PCI bus which have no specific support code so far and, thus,
are picked up as generic SDHCI controllers, hw.sdhci.quirk_set
allows for setting the necessary quirks (if required).
o In mmc(4), check and handle the return values of some more
function calls instead of assuming that everything went right.
In case failures actually are not problematic, indicate that
by casting the return value to void.
Reviewed by: jmcneill
registers.
- Add slot type capability bits. These bits should allow recognizing
removable card slots, embedded cards and shared buses (shared bus
supposedly is always comprised of non-removable cards).
- Dump CAPABILITIES2, ADMA_ERR, HOST_CONTROL2 and ADMA_ADDRESS_LO
registers in sdhci_dumpregs().
- The drive type support flags in the CAPABILITIES2 register are for
drive types A,C,D, drive type B is the default setting (value 0) of
the drive strength field in the SDHCI_HOST_CONTROL2 register.
Obtained from: DragonFlyBSD (9e3c8f63, 455bd1b1)
the default partition, eMMC v4.41 and later devices can additionally
provide up to:
1 enhanced user data area partition
2 boot partitions
1 RPMB (Replay Protected Memory Block) partition
4 general purpose partitions (optionally with a enhanced or extended
attribute)
Of these "partitions", only the enhanced user data area one actually
slices the user data area partition and, thus, gets handled with the
help of geom_flashmap(4). The other types of partitions have address
space independent from the default partition and need to be switched
to via CMD6 (SWITCH), i. e. constitute a set of additional "disks".
The second kind of these "partitions" doesn't fit that well into the
design of mmc(4) and mmcsd(4). I've decided to let mmcsd(4) hook all
of these "partitions" up as disk(9)'s (except for the RPMB partition
as it didn't seem to make much sense to be able to put a file-system
there and may require authentication; therefore, RPMB partitions are
solely accessible via the newly added IOCTL interface currently; see
also below). This approach for one resulted in cleaner code. Second,
it retains the notion of mmcsd(4) children corresponding to a single
physical device each. With the addition of some layering violations,
it also would have been possible for mmc(4) to add separate mmcsd(4)
instances with one disk each for all of these "partitions", however.
Still, both mmc(4) and mmcsd(4) share some common code now e. g. for
issuing CMD6, which has been factored out into mmc_subr.c.
Besides simply subdividing eMMC devices, some Intel NUCs having UEFI
code in the boot partitions etc., another use case for the partition
support is the activation of pseudo-SLC mode, which manufacturers of
eMMC chips typically associate with the enhanced user data area and/
or the enhanced attribute of general purpose partitions.
CAVEAT EMPTOR: Partitioning eMMC devices is a one-time operation.
- Now that properly issuing CMD6 is crucial (so data isn't written to
the wrong partition for example), make a step into the direction of
correctly handling the timeout for these commands in the MMC layer.
Also, do a SEND_STATUS when CMD6 is invoked with an R1B response as
recommended by relevant specifications. However, quite some work is
left to be done in this regard; all other R1B-type commands done by
the MMC layer also should be followed by a SEND_STATUS (CMD13), the
erase timeout calculations/handling as documented in specifications
are entirely ignored so far, the MMC layer doesn't provide timeouts
applicable up to the bridge drivers and at least sdhci(4) currently
is hardcoding 1 s as timeout for all command types unconditionally.
Let alone already available return codes often not being checked in
the MMC layer ...
- Add an IOCTL interface to mmcsd(4); this is sufficiently compatible
with Linux so that the GNU mmc-utils can be ported to and used with
FreeBSD (note that due to the remaining deficiencies outlined above
SANITIZE operations issued by/with `mmc` currently most likely will
fail). These latter will be added to ports as sysutils/mmc-utils in
a bit. Among others, the `mmc` tool of the GNU mmc-utils allows for
partitioning eMMC devices (tested working).
- For devices following the eMMC specification v4.41 or later, year 0
is 2013 rather than 1997; so correct this for assembling the device
ID string properly.
- Let mmcsd.ko depend on mmc.ko. Additionally, bump MMC_VERSION as at
least for some of the above a matching pair is required.
- In the ACPI front-end of sdhci(4) describe the Intel eMMC and SDXC
controllers as such in order to match the PCI one.
Additionally, in the entry for the 80860F14 SDXC controller remove
the eMMC-only SDHCI_QUIRK_INTEL_POWER_UP_RESET.
OKed by: imp
Submitted by: ian (mmc_switch_status() implementation)
comments, marking unused parameters as such, style(9), whitespace,
etc.
o In the mmc(4) bridges and sdhci(4) (bus) front-ends:
- Remove redundant assignments of the default bus_generic_print_child
device method (I've whipped these out of the tree as part of r227843
once, but they keep coming back ...),
- use DEVMETHOD_END,
- use NULL instead of 0 for pointers.
o Trim/adjust includes.
handler which already holds the mutex, and have sdhci_handle_card_present()
be just a tiny wrapper that does the locking for external callers.
This should fix the recursive locking panics seen on rpi3.
Reported by: Shawn Webb
Besides slots always having non-removable media, these HCIs require
a custom hardware reset sequence after power-up.
- Flesh out the support for Intel Braswell eMMC controllers further.
Apart from also requiring said reset code, the timeout clock needs to
be hardcoded to 1 MHz for these.
Both the special reset and timeout clock handlings are implemented as
global sdhci(4) quirks as the same treatment will be necessary for
Intel eMMC controllers attached via ACPI (once sdhci(4) grows such a
front-end).
- In sdhci_init_slot(), use the right capability field for determining
the announced bus width based on MMC_CAP_*_BIT_DATA.
- Correct inverted sdhci_pci_softc member comments added in r276469. [1]
Submitted by: Anton Yuzhaninov [1]
MFC after: 5 days
card insert/remove events on controllers that don't implement the insert
and remove interrupts.
Bridge drivers can set a new slot option, SDHCI_NON_REMOVABLE, to indicate
non-removable media (such as eMMC). The sdhci driver will not enable
insert/remove interrupts, and sdhci_generic_get_card_present() will always
return true.
Bridge drivers can set a new quirk, SDHCI_QUIRK_POLL_CARD_PRESENT, and the
sdhci driver will not enable insert/remove interrupts, and instead will use
a callout to poll the card-present status at 5 Hz.
For bridge drivers that get notified of card insert/remove via gpio
interrupts, there is a new sdhci_handle_card_present() function they can
call from the gpio interrupt handler to inform the sdhci code of the event.
In addition to adding these new features, the existing code to debounce card
insertions was updated to use taskqueue_enqueue_timeout() instead of
scheduling a callout to do the taskqueue_enqueue(). There is also now a
comment explaining that insertion-debounce is what's going on -- it took me
a long time to realize that's what the old sdhci_card_delay() routine was
really doing. There is no functional difference between the old and new
debounce code (I hope!).
Many embedded SoC controllers that are (more or less) sdhci-compatible don't
implement card detect, and the related values in the PRESENT_STATE register
aren't useful. A bridge driver can now implement get_card_present() to read
a gpio pin or whatever else is necessary for that system.
The default implementation reads the CARD_PRESENT bit from the PRESENT_STATE
register, so existing drivers will keep working (or keep not-fully-working,
since many drivers right now can't detect card insert/remove).
Some controllers (namely Freescale's eSDHC, tested) will continue to assert
the card removed or card insert interrupts even after being handled. To work
around this, disable watching the interrupt that just occurred until the
opposite interrupt is triggered.
Linux has a similar change in its driver to address the same problem.
This patch adds support for the BCM57765[2] card reader function included in
Broadcom's BCM57766 ethernet/sd3.0 controller. This controller is commonly
found in laptops and Apple hardware (MBP, iMac, etc).
The BCM57765 chipset is almost fully compatible with the SD3.0 spec, but
does not support deriving a frequency below 781KHz from its default base
clock via the standard SD3.0-configured 10-bit clock divisor.
If such a divisor is set, card identification (which requires a 400KHz
clock frequency) will time out[1].
As a work-around, I've made use of an undocumented device-specific clock
control register to switch the controller to a 63MHz clock source when
targeting clock speeds below 781KHz; the clock source is likewise switched
back to the 200MHz clock when targeting speeds greater than 781KHz.
Additionally, this patch fixes a small sdhci_pci bug; the
sdhci_pci_softc->quirks flag was not copied to the sdhci_slot, resulting in
`quirk` behavior not being applied by sdhci.c.
[1] A number of Linux/FreeBSD users have noted that bringing up the chipsets'
associated ethernet interface will allow SD cards to enumerate (slowly).
This is a controller implementation side-effect triggered by the ethernet
driver's reading of the hardware statistics registers.
[2] This may also fix card detection when using the BCM57785 chipset, but I
don't have access to the BCM57785 chipset and can't verify.
I actually snagged some BCM57785 hardware recently (2012 Retina MacBook Pro)
and can confirm that this also fixes card enumeration with the BCM57785
chipset; with the patch, I can boot off of the internal sdcard reader.
PR: kern/203385
Submitted by: Landon Fuller <landon@landonf.org>
this value at runtime.
The SD card specification says that a block write or a block erase can take
up to 250ms to complete and thus, under some circumstances, the existent 2
seconds timeout was triggering with normal usage.
This change fixes the sporadic controller timeout that happens on RPi and
RPi 2.
Discussed with: ian (some time ago)
sdhci controllers, such as the one on a Raspberry Pi, mishandle the signal
timing in high speed signaling mode, but run just fine in standard mode
with the bus running at frequencies between 25-50MHz (which shouldn't work).
This is the solution adopted by U-Boot and other OSes (linux and *BSD)
for the timeouts on Raspberry Pi boards with certain SD cards. Some
research shows that this quirk is also used on a few other boards, so the
fix is a generic quirk instead of being in the RPi-specific driver code.
This change is based on information discovered by Michal Meloun.
moving the handling of curcmd->error != 0 to the end of the interrupt
handler. Also make sdhci_finish_data() idempotent by moving the setting
of slot->data_done = 1 down past the point where the busdma buffer is
unmapped. This allows for the possibility that the finish routine can
get called from multiple places when handling errors.
TI OMAP controllers which will return the reset-in-progress bit as zero if
you read the status register too fast after setting the reset bit.
The zero is apparently from a stale snapshot of the internal state presented
in the interface register, and leads to a false indication that the reset
is complete when it either hasn't started yet or is in-progress. The
workaround is to first loop until the bit is seen as asserted, then do the
normal loop waiting to see it de-asserted.
Submitted by: Michal Meloun <meloun@miracle.cz>
- Static'ize sdhci_debug local to sdhci.c.
- Const'ify PCI device description strings.
- Nuke redundant resource ID members from sdhci_pci_softc.
- Nuke unused hw.sdhci_pci.debug tunable.
- Add support for using MSI instead of INTx, controllable via the tunable
hw.sdhci.enable_msi (defaulting to on) and tested with a RICOH R5CE823 SD
controller.
- Use NULL instead of 0 for pointers.
MFC after: 3 days
These changes prevent sysctl(8) from returning proper output,
such as:
1) no output from sysctl(8)
2) erroneously returning ENOMEM with tools like truss(1)
or uname(1)
truss: can not get etype: Cannot allocate memory
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.
Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.
MFC after: 2 weeks
Sponsored by: Mellanox Technologies
before changing the divisor bits in the register. We were writing a zero
to the register, which clears the enable, but also cleared the divisor bits
at the same time. That's a violation of the sdhci spec, which says the
divisor can only be changed when the clock is disabled. This has worked
okay on most hardware for years, but the TI OMAP controller would misbehave
after changing the divisor improperly.
Submitted by: Svatopluk Kraus <onwahe@gmail.com>
rather than SDHCI_RESET_ALL; the latter turns off clocks and power, removing
any possibility of recovering from the error.
Also, double the timeout to 2 seconds. Despite what the SD spec says about
all transactions completing in 250ms or less, I have a card which sometimes
takes more than a second to complete a write.
If the hardware is not in a good state (like maybe clocks aren't running
because of a configuration glitch) its timeout clock may also not work
correctly, and the next command sent will hang that thread forever. The
thread in question is usually the one and only thread (at init time) or
a bio queue worker thread whose lockup will eventually lead to the whole
system locking up when it runs out of buffers.
No sd card command should take longer than 250ms. This new code establishes
a 1-second timeout to allow plenty of safety margin over that.
Normally it never needs to wait here at all; waiting is done at the end
of the prior command. When doing a crash dump, the normal interrupt
mechanism isn't used; instead the interrupt handler is called repeatedly
in a polling-like manner. This can subvert hardware-specific drivers
and lead to trying to start a new command while the previous command is
still busy on the bus. Since the SD spec says the longest a card can
take to execute any command is 250ms, use that as a timeout.
The sdhci spec says that if the base or timeout clock frequency in the
capabilities register is zero, the driver must obtain the frequency "from
another source." This change defines that other source to be the low-level
hardware driver, which can pre-set the frequencies in slot.max_clk and
slot.timeout_clk before calling sdhci_init_slot().
This helps with a growing number of SoCs that have sdhci base clock
frequencies that either won't fit into the range allowed by the number of
bits available in the capabilities register, or the frequency is runtime-
configurable.
the response bits the way we do in software. While the hardware is just
doing the sensible thing rather than leaving it to the software, it's in
violation of the spec by doing so. Grrrr.
has to be recalculated every time the SD clock frequency changes.
Also, tidy up the counter calculation... it makes no sense to calculate
a value one larger than the limit, then whine that it's too large and
truncate it to the limit. If the BROKEN_TIMEOUT quirk is set, don't
calculate the counter at all, just set it to the limit value.
In order to use platorm backend hardware driver should
impement three methods:
- platform_start_transfer and platform_finish_transfer
to start and finish transfer
- platform_will_handle - check whether transaction is
suitable for backend. If not - driver will fall back
to PIO mode.
Submitted by: Daisuke Aoyama <aoyama at peach.ne.jp>
Approved by: ian@
- Replace divisor numbers with more descirptive names
- Properly calculate minimum frequency for SDHCI 3.0
- Properly calculate frequency for SDHCI 3.0 in mmcbr_set_clock
- Add min_freq method to sdhci_if.m and provide default
implementation. By re-implementing this method hardware
drivers can control frequency controller operates when
executing initialization sequence
sdchi encapsulates a generic SD Host Controller logic that relies on
actual hardware driver for register access.
sdhci_pci implements driver for PCI SDHC controllers using new SDHCI
interface
No kernel config modifications are required, but if you load sdhc
as a module you must switch to sdhci_pci instead.
