The latest SPI controllers embedded inside sama5d2x SoCs come with FIFOs.
When FIFOs are enabled, they can either work in SINGLE data mode or
MULTIPLE data mode. The selected mode depends on the configuration of the
SPI controller (see below).
In SINGLE data mode (or legacy mode), for a single I/O access, only one
data can be read from the Receive Data Register (RDR) or written into the
Transmit Data Register (TDR). On the other hand, in MULTIPLE data mode, up
to 4 data can be read from the RDR or up 2 data can be written into the
TDR in a single 32bit I/O access. So programmers should take good care of
the width of the I/O access to read/write the right number of data. The
exact number of read/written data depends on both the I/O access width and
the data width (from 8 up to 16 bits).
To enable the FIFO feature a "atmel,fifo-size" property must be set to
provide the maximum number of data (not bytes) the RX and TX FIFOs can
store. Hence a 32 data FIFO can always store up to 32 data unrelated with
the actual data width.
When FIFOs are enabled, the RX one is forced to operate in SINGLE data
mode because this driver configures the spi controller as a master. In
master mode only, the Received Data Register has an additionnal Peripheral
Chip Select field, which prevents us from reading more than a single data
at each register access.
Besides, the TX FIFO operates in MULTIPLE data mode. However, even when a
8bit data size is used, only two data by access could be written into the
Transmit Data Register. Indeed the first data has to be written into the
lowest 16 bits whereas the second data has to be written into the highest
16 bits of the TDR. When DMA transfers are used to send data, we don't
rework the transmit buffer to cope with this hardware limitation: the
additional copies required to prepare a new input buffer suited to both
the DMA controller and the spi controller would waste all the benefit of
the DMA transfer. Instead, the DMA controller is configured to write only
one data at time into the TDR.
In pio mode, two data are written in the TDR in a single access.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
- add new property "atmel,fifo-size"
- change "cs-gpios" to optional for SPI controller version >= 2.
Please be aware that the VERSION register can not be used to guess the
size of FIFOs. Indeed, for a given hardware version, the SPI controller
can be integrated on Atmel SoCs with different FIFO sizes. Also the
"atmel,fifo-size" property is optional as older SPI controllers don't
embed FIFO at all.
Besides, the FIFO size can not be read or guessed from other registers:
When designing the FIFO feature, no dedicated registers were added to
store this size. Unused spaces in the I/O register range are limited and
better reserved for future usages. Instead, the FIFO size of each
peripheral is documented in the programmer datasheet.
Finally, on a given SoC, there can be several instances of the SPI
controller with different FIFO sizes. This explain why we'd rather use a
dedicated DT property than use the "compatible" property.
For instance, sama5d2x SoCs come with some SPI controllers, the ones
inside Flexcoms, integrating 32 data FIFOs whereas other SPI controllers
use 16 data FIFOs. All these SPI controllers share the same IP version.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
DSPI driver has been updated and support more compatible strings.
This patch update the DT binding documentation.
Signed-off-by: Haikun Wang <haikun.wang@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Constify the ACPI device ID array, it doesn't need to be writable at
runtime.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Pull dmaengine fixes from Vinod Koul:
"Here are hopefully last set of fixes for 4.1. This time we have:
- fixing pause capability reporting on both dmaengine pause & resume
support by Krzysztof
- locking fix fir at_xdmac by Ludovic
- slave configuration fix for at_xdmac by Ludovic"
* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
dmaengine: Fix choppy sound because of unimplemented resume
dmaengine: at_xdmac: rework slave configuration part
dmaengine: at_xdmac: lock fixes
Pull NTB fixes from Jon Mason:
"I apologize for the tardiness of this request. Here are a couple of
last minute NTB bug fixes for v4.1:
NTB bug fixes to address issues in unmapping the MW reg base and
vbase, and an uninitialized variable on Atom platforms"
* tag 'ntb-4.1' of git://github.com/jonmason/ntb:
ntb: initialize max_mw for Atom before using it
ntb: iounmap MW reg and vbase in error path
Pull more MIPS fixes from Ralf Baechle:
"Another round of 4.1 MIPS fixes, one fix to a MIPS-specific #if
condition in lib/mpi, one fix to the MIPS GIC irqchip driver and one
SSB fix.
Details:
- fix handling of clock in chipco SSB driver.
- fix two MIPS-specific #if conditions to correctly work for GCC 5.1.
- fix damage to R6 pgtable bits done by XPA support.
- fix possible crash due to unloading modules that contain statically
defined platform devices.
- fix disabling of the MSA ASE on context switch to also work
correctly when a new thread/process has the CPU for the very first
time.
This is part of linux-next and has been beaten to death on
Imagination's test farm.
While things are not looking too grim this pull request also means the
rate of fixes for 4.1 remains nearly constant so I'd not be unhappy if
you'd delay the release"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
MPI: MIPS: Fix compilation error with GCC 5.1
IRQCHIP: mips-gic: Don't nest calls to do_IRQ()
MIPS: MSA: bugfix - disable MSA correctly for new threads/processes.
MIPS: Loongson: Do not register 8250 platform device from module.
MIPS: Cobalt: Do not build MTD platform device registration code as module.
SSB: Fix handling of ssb_pmu_get_alp_clock()
MIPS: pgtable-bits: Fix XPA damage to R6 definitions.
Pull irqchip fix from Thomas Gleixner:
"A single fix for an off by one bug in the sunxi irqchip driver"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip: sunxi-nmi: Fix off-by-one error in irq iterator
Pull lockdep fix from Ingo Molnar:
"A lockdep/modules unload race fix that can oops"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
lockdep: Fix a race between /proc/lock_stat and module unload
Pull perf fixes from Ingo Molnar:
"A regression fix for a crash, and a Intel HSW uncore PMU driver fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "perf/x86/intel/uncore: Move uncore_box_init() out of driver initialization"
perf/x86/intel/uncore: Fix CBOX bit wide and UBOX reg on Haswell-EP
Pull sound fixes from Takashi Iwai:
"Most of commits are regression fixes for HD-audio: a few corner case
fixes for regmap transition, and i915 binding issues.
In addition, a quirk for another USB-audio device supporting DSD"
* tag 'sound-4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda - Abort the probe without i915 binding for HSW/BDW
ALSA: hda - Re-add the lost fake mute support
ALSA: hda - Continue probing even if i915 binding fails
ALSA: hda - Don't actually write registers for caps overwrites
ALSA: hda - fix number of devices query on hotplug
ALSA: usb-audio: add native DSD support for JLsounds I2SoverUSB
The GIC chained handlers use do_IRQ() to call the subhandlers. This
means that irq_enter() calls get nested, which leads to preempt count
looking like we're in nested interrupts, which in turn leads to all
system time being accounted as IRQ time in account_system_time().
Fix it by using generic_handle_irq(). Since these same functions are
used in some systems (if cpu_has_veic) from a low-level vectored
interrupt handler which does not go throught do_IRQ(), we need to do it
conditionally.
Signed-off-by: Rabin Vincent <rabin.vincent@axis.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: tglx@linutronix.de
Cc: jason@lakedaemon.net
Patchwork: https://patchwork.linux-mips.org/patch/10545/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull networking fixes from David Miller:
1) Fix uninitialized struct station_info in cfg80211_wireless_stats(),
from Johannes Berg.
2) Revert commit attempt to fix ipv6 protocol resubmission, it adds
regressions.
3) Endless loops can be created in bridge port lists, fix from Nikolay
Aleksandrov.
4) Don't WARN_ON() if sk->sk_forward_alloc is non-zero in
sk_clear_memalloc, it is a legal situation during swap deactivation.
Fix from Mel Gorman.
5) Fix order of disabling interrupts and unlocking NAPI in enic driver
to avoid a race. From Govindarajulu Varadarajan.
6) High and low register writes are swapped when programming the start
of periodic output in igb driver. From Richard Cochran.
7) Fix device rename handling in mpls stack, from Robert Shearman.
8) Do not trigger compaction synchronously when optimistically trying
to allocate an order 3 page in alloc_skb_with_frags() and
skb_page_frag_refill(). From Shaohua Li.
9) Authentication with COOKIE_ECHO is not handled properly in SCTP, fix
from Marcelo Ricardo Leitner.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
Doc: networking: Fix URL for wiki.wireshark.org in udplite.txt
sctp: allow authenticating DATA chunks that are bundled with COOKIE_ECHO
net: don't wait for order-3 page allocation
mpls: handle device renames for per-device sysctls
net: igb: fix the start time for periodic output signals
enic: fix memory leak in rq_clean
enic: check return value for stat dump
enic: unlock napi busy poll before unmasking intr
net, swap: Remove a warning and clarify why sk_mem_reclaim is required when deactivating swap
bridge: fix multicast router rlist endless loop
tipc: disconnect socket directly after probe failure
Revert "ipv6: Fix protocol resubmission"
cfg80211: wext: clear sinfo struct before calling driver
This patch fix URL (http to https) for wiki.wireshark.org.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
