Replace ternary (condition ? "enable" : "disable") syntax with helpers
from string_choices.h because:
1. Simple function call with one argument is easier to read. Ternary
operator has three arguments and with wrapping might lead to quite
long code.
2. Is slightly shorter thus also easier to read.
3. It brings uniformity in the text - same string.
4. Allows deduping by the linker, which results in a smaller binary
file.
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250114190612.846696-1-krzysztof.kozlowski@linaro.org
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
We now free the temporary target path substring allocation on every
possible branch, instead of omitting the default branch. In some
cases, a memory leak occured, which could rapidly crash the system
(depending on how many file accesses were attempted).
This was detected in production because it caused a continuous memory
growth, eventually triggering kernel OOM and completely hard-locking
the kernel.
Relevant kmemleak stacktrace:
unreferenced object 0xffff888131e69900 (size 128):
comm "git", pid 66104, jiffies 4295435999
hex dump (first 32 bytes):
76 6f 6c 75 6d 65 73 2f 63 6f 6e 74 61 69 6e 65 volumes/containe
72 73 2f 67 69 74 65 61 2f 67 69 74 65 61 2f 67 rs/gitea/gitea/g
backtrace (crc 2f3bb450):
[<ffffffffaa68fb49>] __kmalloc_noprof+0x359/0x510
[<ffffffffc32bf1df>] ceph_mds_check_access+0x5bf/0x14e0 [ceph]
[<ffffffffc3235722>] ceph_open+0x312/0xd80 [ceph]
[<ffffffffaa7dd786>] do_dentry_open+0x456/0x1120
[<ffffffffaa7e3729>] vfs_open+0x79/0x360
[<ffffffffaa832875>] path_openat+0x1de5/0x4390
[<ffffffffaa834fcc>] do_filp_open+0x19c/0x3c0
[<ffffffffaa7e44a1>] do_sys_openat2+0x141/0x180
[<ffffffffaa7e4945>] __x64_sys_open+0xe5/0x1a0
[<ffffffffac2cc2f7>] do_syscall_64+0xb7/0x210
[<ffffffffac400130>] entry_SYSCALL_64_after_hwframe+0x77/0x7f
It can be triggered by mouting a subdirectory of a CephFS filesystem,
and then trying to access files on this subdirectory with an auth token
using a path-scoped capability:
$ ceph auth get client.services
[client.services]
key = REDACTED
caps mds = "allow rw fsname=cephfs path=/volumes/"
caps mon = "allow r fsname=cephfs"
caps osd = "allow rw tag cephfs data=cephfs"
$ cat /proc/self/mounts
services@[REDACTED].cephfs=/volumes/containers /ceph/containers ceph rw,noatime,name=services,secret=<hidden>,ms_mode=prefer-crc,mount_timeout=300,acl,mon_addr=[REDACTED]:3300,recover_session=clean 0 0
$ seq 1 1000000 | xargs -P32 --replace={} touch /ceph/containers/file-{} && \
seq 1 1000000 | xargs -P32 --replace={} cat /ceph/containers/file-{}
[ idryomov: combine if statements, rename rc to path_matched and make
it a bool, formatting ]
Cc: stable@vger.kernel.org
Fixes: 596afb0b8933 ("ceph: add ceph_mds_check_access() helper")
Signed-off-by: Antoine Viallon <antoine@lesviallon.fr>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Enable DCC (Duty Cycle Control) in Lunar Lake.
DCC is the SLPC task that tries to keep
the GT from operating inefficiently when thermally constrained.
Although the recommendation is to enable it, LNL GuC is leaving
it disabled by default on LNL.
It would minimize the GT frequency oscillation on throttled
scenarios, which could potentially reduce latencies.
v2: Move set_policies call after wait for running state, so
we ensure it is not overwritten. (Vinay)
v3: Fix English in the commit message (Jonathan)
v4: Also set disable to 0 so DCC can really get into effect.
v5: Avoid lnl_ prefix (Vinay)
v6: Finish renaming...
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com> #v3
Link: https://patchwork.freedesktop.org/patch/msgid/20250115145053.1142023-2-rodrigo.vivi@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Allows the visualization of the current GuC power conservation
status and policies.
v2: Fix DCC msg (Vinay)
v3: Simplify pc_get_state_string (Jonathan)
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250115145053.1142023-1-rodrigo.vivi@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
* pci-sysfs:
PCI/sysfs: Remove unnecessary zero in initializer
PCI/sysfs: Use __free() in reset_method_store()
PCI/sysfs: Move reset related sysfs code to correct file
* err:
PCI: Add pcie_print_tlp_log() to print TLP Header and Prefix Log
PCI: Add TLP Prefix reading to pcie_read_tlp_log()
PCI: Store number of supported End-End TLP Prefixes
PCI: Use unsigned int i in pcie_read_tlp_log()
PCI: Use same names in pcie_read_tlp_log() prototype and definition
PCI: Add defines for TLP Header/Prefix log sizes
PCI: Move TLP Log handling to its own file
PCI: Don't expose pcie_read_tlp_log() outside PCI subsystem
* endpoint:
PCI: endpoint: pci-epf-test: Set dma_chan_rx pointer to NULL on error
misc: pci_endpoint_test: Add support for capabilities
PCI: endpoint: pci-epf-test: Add support for capabilities
PCI: endpoint: Verify that requested BAR size is a power of two
PCI: endpoint: Add size check for fixed size BARs in pci_epc_set_bar()
PCI: artpec6: Implement dw_pcie_ep operation get_features
PCI: dwc: ep: Add 'address' alignment to 'size' check in dw_pcie_prog_ep_inbound_atu()
PCI: dwc: ep: Prevent changing BAR size/flags in pci_epc_set_bar()
PCI: dwc: ep: Write BAR_MASK before iATU registers in pci_epc_set_bar()
PCI: endpoint: Finish virtual EP removal in pci_epf_remove_vepf()
PCI: endpoint: Simplify pci_epc_get()
PCI: endpoint: Destroy the EPC device in devm_pci_epc_destroy()
PCI: endpoint: Replace magic number '6' by PCI_STD_NUM_BARS
* devres:
HID: amd_sfh: Use always-managed version of pcim_intx()
wifi: qtnfmac: use always-managed version of pcim_intx()
ata: Use always-managed version of pci_intx()
PCI/MSI: Use never-managed version of pci_intx()
vfio/pci: Use never-managed version of pci_intx()
misc: Use never-managed version of pci_intx()
ntb: Use never-managed version of pci_intx()
drivers/xen: Use never-managed version of pci_intx()
PCI: Export pci_intx_unmanaged() and pcim_intx()
* controller/mediatek:
PCI: mediatek-gen3: Enable async probe by default
PCI: mediatek-gen3: Avoid PCIe resetting via PERST# for Airoha EN7581 SoC
PCI: mediatek-gen3: Rely on msleep() in mtk_pcie_en7581_power_up()
PCI: mediatek-gen3: Move reset delay in mtk_pcie_en7581_power_up()
PCI: mediatek-gen3: Add comment about initialization order in mtk_pcie_en7581_power_up()
PCI: mediatek-gen3: Move reset/assert callbacks in .power_up()
PCI: mediatek-gen3: Rely on clk_bulk_prepare_enable() in mtk_pcie_en7581_power_up()
* controller/imx6:
PCI: imx6: Add IOMMU and ITS MSI support for i.MX95
PCI: Add enable_device() and disable_device() callbacks for bridges
# Conflicts:
# drivers/pci/controller/dwc/pci-imx6.c
* controller/dwc:
arm64: dts: imx95: Add ref clock for i.MX95 PCIe
PCI: imx6: Add i.MX8MQ, i.MX8Q and i.MX95 PM support
PCI: imx6: Use DWC common suspend resume method
PCI: imx6: Remove surplus imx7d_pcie_init_phy() function
PCI: imx6: Fix the missing reference clock disable logic
PCI: imx6: Deassert apps_reset in imx_pcie_deassert_core_reset()
PCI: imx6: Fix controller_id generation logic for i.MX7D
PCI: imx6: Fetch dbi2 and iATU base addesses from DT
PCI: imx6: Add ref clock for i.MX95 PCIe
dt-bindings: imx6q-pcie: Add ref clock for i.MX95 PCIe RC
PCI: dwc: layerscape: Use syscon_regmap_lookup_by_phandle_args
PCI: dwc: dra7xx: Use syscon_regmap_lookup_by_phandle_args
PCI: imx6: Add i.MX8Q PCIe Endpoint (EP) support
PCI: imx6: Pass correct sub mode when calling phy_set_mode_ext()
dt-bindings: PCI: fsl,imx6q-pcie-ep: Add compatible string fsl,imx8q-pcie-ep
PCI: imx6: Remove cpu_addr_fixup()
PCI: dwc: ep: Add bus_addr_base for outbound window
PCI: dwc: Use devicetree 'ranges' property to get rid of cpu_addr_fixup() callback
of: address: Add parent_bus_addr to struct of_pci_range
PCI: dwc: Clean up some unnecessary codes in dw_pcie_suspend_noirq()
PCI: dwc: Always stop link in the dw_pcie_suspend_noirq
PCI: dwc: Fix potential truncation in dw_pcie_edma_irq_verify()
PCI: dw-rockchip: Remove redundant calls to dev_err()
PCI: dw-rockchip: Replace magic values with defines
PCI: dw-rockchip: Don't wait for link since we can detect Link Up
PCI: dw-rockchip: Enumerate endpoints based on dll_link_up IRQ
PCI: qcom: Update ICC and OPP values after Link Up event
PCI: qcom: Don't wait for link if we can detect Link Up
PCI: dwc: Skip waiting for link up if driver can detect Link Up event
Running 'pcitest -b 2' fails with "TEST FAILED" when the BAR2 size
exceeds 4GB.
The return value of the pci_resource_len() macro can be larger than that
of a signed integer type. As such, for example, when using 'pcitest'
with an 8GB BAR2, the bar_size of the integer type will overflow.
Thus, change the data type of bar_size from integer to resource_size_t,
to fix the integer overflow for large BAR sizes.
Link: https://lore.kernel.org/r/20250109094556.1724663-3-18255117159@163.com
Signed-off-by: Hans Zhang <18255117159@163.com>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
A BAR size is always a power of two. buf_size = min(SZ_1M, bar_size);
If the BAR size is <= 1MB, there will be 1 iteration, no remainder. If
the BAR size is > 1MB, there will be more than one iteration, but the
size will always be evenly divisible by 1MB, so no remainder.
Link: https://lore.kernel.org/r/20250109094556.1724663-2-18255117159@163.com
Suggested-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Hans Zhang <18255117159@163.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
ktime_get_fast_timestamps() was added in 2020 by commit e2d977c9f1ab
("timekeeping: Provide multi-timestamp accessor to NMI safe timekeeper")
but has remained unused.
Remove it.
[ tglx: Fold the inline as David suggested in the submission ]
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250112160132.450209-1-linux@treblig.org
Use the correct kernel-doc notation for nested structs/unions to
eliminate warnings:
timer_migration.h:119: warning: Incorrect use of kernel-doc format: * struct - split state of tmigr_group
timer_migration.h:134: warning: Function parameter or struct member 'active' not described in 'tmigr_state'
timer_migration.h:134: warning: Function parameter or struct member 'migrator' not described in 'tmigr_state'
timer_migration.h:134: warning: Function parameter or struct member 'seq' not described in 'tmigr_state'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250111063156.910903-1-rdunlap@infradead.org
Add kernel-doc comments for two parameters to eliminate kernel-doc warnings:
tick-broadcast.c:1026: warning: Function parameter or struct member 'bc' not described in 'tick_broadcast_setup_oneshot'
tick-broadcast.c:1026: warning: Function parameter or struct member 'from_periodic' not described in 'tick_broadcast_setup_oneshot'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250111063148.910887-1-rdunlap@infradead.org
The return type should be 'bool' instead of 'int' according to the calling
context in the kernel, and its internal implementation, i.e. :
return timerqueue_add();
which is a bool-return function.
[ tglx: Adjust function arguments ]
Signed-off-by: Richard Clark <richard.xnu.clark@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/Z2ppT7me13dtxm1a@MBC02GN1V4Q05P
When a pair of clocksource reads separated by a udelay(1) claim less than a
full microsecond of elapsed time, print the measured delay as part of the
splat.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/717a2ddf-a80f-490b-aa3a-4e4b74fa56ca@paulmck-laptop
Refactor rockchip_pcie_disable_clocks() to accept a struct rockchip_pcie
pointer instead of a void pointer thus improving type safety and code
readability by explicitly specifying the expected data type.
Link: https://lore.kernel.org/r/20241202151150.7393-4-linux.amoon@gmail.com
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Currently, the driver acquires and asserts/deasserts the resets
individually thereby making the driver complex to read.
This can be simplified by using the reset_control_bulk() APIs.
Use devm_reset_control_bulk_get_exclusive() API to acquire all the resets
and use reset_control_bulk_{assert/deassert}() APIs to assert/deassert them
in bulk.
Following the recommendations in 'Rockchip RK3399 TRM v1.3 Part2':
1. Split the reset controls into two groups as per section '17.5.8.1.1
PCIe as Root Complex'.
2. Deassert the 'Pipe, MGMT Sticky, MGMT, Core' resets in groups as per
section '17.5.8.1.1 PCIe as Root Complex'. This is accomplished using
the reset_control_bulk APIs.
Link: https://lore.kernel.org/r/20241202151150.7393-3-linux.amoon@gmail.com
Co-developed-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
[kwilczynski: squash error handling fix from https://lore.kernel.org/r/7da6ac56-af55-4436-9597-6af24df8122c@stanley.mountain]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Add ref clock for i.MX95 PCIe when the internal PLL is used as PCIe
reference clock.
Link: https://lore.kernel.org/r/20241126075702.4099164-11-hongxing.zhu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
The use of of_property_read_bool() for non-boolean properties is
deprecated in favor of of_property_present() when testing for property
presence.
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Letting the compiler remove these functions when the kernel is built
without CONFIG_PM_SLEEP support is simpler and less error prone than the
use of #ifdef based kernel configuration guards.
Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
For the i.MX95, the configuration of a LUT is necessary to convert PCIe
Requester IDs (RIDs) to StreamIDs, which are used by both IOMMU and ITS.
This involves checking msi-map and iommu-map device tree properties to
ensure consistent mapping of Requester IDs to the same StreamIDs.
Subsequently, LUT-related registers are configured. If a msi-map isn't
detected, the platform relies on DWC built-in controller for MSIs that
do not need StreamIDs.
Implement PCI bus callback function to handle enable_device() and
disable_device() operations, setting up the LUT whenever a new PCI
device is enabled.
Known limitations:
- If iommu-map exists in the device tree but the IOMMU controller is
disabled, StreamIDs are programmed into the LUT. However, if a RID
is out of range of the iommu-map, enabling the PCI device would
result in a failure, although the PCI device can work without the
IOMMU.
- If msi-map exists in the device tree but the MSI controller is
disabled, MSIs will not work. The DWC driver skips initializing the
built-in MSI controller, falling back to legacy PCI INTx only.
Link: https://lore.kernel.org/r/20250114-imx95_lut-v9-2-39f58dbed03a@nxp.com
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
Some PCI host bridges require special handling when enabling or
disabling PCI devices. For example, the i.MX95 platform has a lookup
table to map Requester IDs to StreamIDs, which the SMMU and MSI
controller use to identify the source of DMA accesses.
Without this mapping, DMA accesses may target unintended memory, which
would corrupt memory or read the wrong data.
Add a host bridge enable_device() hook the imx6 driver can use to
configure the Requester ID to StreamID mapping. The hardware table isn't
big enough to map all possible Requester IDs, so this hook may fail if
no table space is available. In that case, return failure from
pci_enable_device().
It might make more sense to make pci_set_master() decline to enable bus
mastering and return failure, but it currently doesn't have a way to return
failure.
Link: https://lore.kernel.org/r/20250114-imx95_lut-v9-1-39f58dbed03a@nxp.com
Tested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Apparently the Raptor Lake-P reference firmware configures the PIO log size
correctly, but some vendor BIOSes, including at least ASUSTeK COMPUTER INC.
Zenbook UX3402VA_UX3402VA, do not.
Apply the quirk for Raptor Lake-P. This prevents kernel complaints like:
DPC: RP PIO log size 0 is invalid
and also enables the DPC driver to dump the RP PIO Log registers when DPC
is triggered.
Note that the bug report also mentions 8086:a76e, which has been already
added by 627c6db20703 ("PCI/DPC: Quirk PIO log size for Intel Raptor Lake
Root Ports").
Link: https://lore.kernel.org/r/20250102164315.7562-1-tiwai@suse.de
Link: https://bugzilla.suse.com/show_bug.cgi?id=1234623
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
When porting librseq commit:
commit c7b45750fa85 ("Adapt to glibc __rseq_size feature detection")
from librseq to the kernel selftests, the following line was missed
at the end of rseq_init():
rseq_size = get_rseq_kernel_feature_size();
which effectively leaves rseq_size initialized to -1U when glibc does not
have rseq support. glibc supports rseq from version 2.35 onwards.
In a following librseq commit
commit c67d198627c2 ("Only set 'rseq_size' on first thread registration")
to mimic the libc behavior, a new approach is taken: don't set the
feature size in 'rseq_size' until at least one thread has successfully
registered. This allows using 'rseq_size' in fast-paths to test for both
registration status and available features. The caveat is that on libc
either all threads are registered or none are, while with bare librseq
it is the responsability of the user to register all threads using rseq.
This combines the changes from the following librseq git commits:
commit c7b45750fa85 ("Adapt to glibc __rseq_size feature detection")
commit c67d198627c2 ("Only set 'rseq_size' on first thread registration")
Fixes: a0cc649353bb ("selftests/rseq: Fix mm_cid test failure")
Reported-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Raghavendra Rao Ananta <rananta@google.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Carlos O'Donell <carlos@redhat.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Michael Jeanson <mjeanson@efficios.com>
Cc: linux-kselftest@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Plumb the DSB down into intel_vrr_send_push() so that we can
perform the opration on the DSB.
TRANS_PUSH, being a transcoder register, needs non-posted writes
to make it through.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241210211007.5976-17-ville.syrjala@linux.intel.com
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
On ICL/TGL the VRR hardware injects an extra scanline just after
vactive. This essentically behaves the same as an extra line of
vblank delay, except it only appears in this one specific spot.
Consider our DSB interrupt signalling scheme:
1. arm the update
2. wait for undelayed vblank (or rather safe window with VRR)
3. wait for enough usecs to get past the delayed vblank
4. signal interrupt to indicate that arming has latched
If step 2 waits for end of vactive step 3 needs to account for
the extra one scanline, or else we risk signalling the interrupt
before the delayed vblank has actually elapsed. So include the
extra scanline in our vblank delay estimates.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241210211007.5976-16-ville.syrjala@linux.intel.com
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
This reverts commit 98d1fb94ce75f39febd456d6d3cbbe58b6678795.
The commit uses data nbits instead of addr nbits for dummy phase. This
causes a regression for all boards where spi-tx-bus-width is smaller
than spi-rx-bus-width. It is a common pattern for boards to have
spi-tx-bus-width == 1 and spi-rx-bus-width > 1. The regression causes
all reads with a dummy phase to become unavailable for such boards,
leading to a usually slower 0-dummy-cycle read being selected.
Most controllers' supports_op hooks call spi_mem_default_supports_op().
In spi_mem_default_supports_op(), spi_mem_check_buswidth() is called to
check if the buswidths for the op can actually be supported by the
board's wiring. This wiring information comes from (among other things)
the spi-{tx,rx}-bus-width DT properties. Based on these properties,
SPI_TX_* or SPI_RX_* flags are set by of_spi_parse_dt().
spi_mem_check_buswidth() then uses these flags to make the decision
whether an op can be supported by the board's wiring (in a way,
indirectly checking against spi-{rx,tx}-bus-width).
Now the tricky bit here is that spi_mem_check_buswidth() does:
if (op->dummy.nbytes &&
spi_check_buswidth_req(mem, op->dummy.buswidth, true))
return false;
The true argument to spi_check_buswidth_req() means the op is treated as
a TX op. For a board that has say 1-bit TX and 4-bit RX, a 4-bit dummy
TX is considered as unsupported, and the op gets rejected.
The commit being reverted uses the data buswidth for dummy buswidth. So
for reads, the RX buswidth gets used for the dummy phase, uncovering
this issue. In reality, a dummy phase is neither RX nor TX. As the name
suggests, these are just dummy cycles that send or receive no data, and
thus don't really need to have any buswidth at all.
Ideally, dummy phases should not be checked against the board's wiring
capabilities at all, and should only be sanity-checked for having a sane
buswidth value. Since we are now at rc7 and such a change might
introduce many unexpected bugs, revert the commit for now. It can be
sent out later along with the spi_mem_check_buswidth() fix.
Fixes: 98d1fb94ce75 ("mtd: spi-nor: core: replace dummy buswidth from addr to data")
Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Closes: https://lore.kernel.org/linux-mtd/3342163.44csPzL39Z@steina-w/
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Pratyush Yadav <pratyush@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
