Some subsystems, such as pinctrl, allow continuing to defer probe
indefinitely. This is useful for devices that depend on resources
provided by devices that are only probed after the init stage.
One example of this can be seen on Tegra, where the DPAUX hardware
contains pinmuxing controls for pins that it shares with an I2C
controller. The I2C controller is typically used for communication
with a monitor over HDMI (DDC). However, other instances of the I2C
controller are used to access system critical components, such as a
PMIC. The I2C controller driver will therefore usually be a builtin
driver, whereas the DPAUX driver is part of the display driver that
is loaded from a module to avoid bloating the kernel image with all
of the DRM/KMS subsystem.
In this particular case the pins used by this I2C/DDC controller
become accessible very late in the boot process. However, since the
controller is only used in conjunction with display, that's not an
issue.
Unfortunately the driver core currently outputs a warning message
when a device fails to get the pinctrl before the end of the init
stage. That can be confusing for the user because it may sound like
an unwanted error occurred, whereas it's really an expected and
harmless situation.
In order to eliminate this warning, this patch allows callers of the
driver_deferred_probe_check_state() helper to specify that they want
to continue deferring probe, regardless of whether we're past the
init stage or not. All of the callers of that function are updated
for the new signature, but only the pinctrl subsystem passes a true
value in the new persist parameter if appropriate.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190621151725.20414-1-thierry.reding@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The cacheinfo structures are alloced/freed by cpu online/offline
callbacks. Originally these were only used by sysfs to expose the
cache topology to user space. Without any in-kernel dependencies
CPUHP_AP_ONLINE_DYN was an appropriate choice.
resctrl has started using these structures to identify CPUs that
share a cache. It updates its 'domain' structures from cpu
online/offline callbacks. These depend on the cacheinfo structures
(resctrl_online_cpu()->domain_add_cpu()->get_cache_id()->
get_cpu_cacheinfo()).
These also run as CPUHP_AP_ONLINE_DYN.
Now that there is an in-kernel dependency, move the cacheinfo
work earlier so we know its done before resctrl's CPUHP_AP_ONLINE_DYN
work runs.
Fixes: 2264d9c74d ("x86/intel_rdt: Build structures for each resource based on cache topology")
Cc: <stable@vger.kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20190624173656.202407-1-james.morse@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The example of the EHCI binding generates a bunch of warnings now that the
examples are validated too.
Most notably, phy-names isn't used at all, and the node name should be USB.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
When adding support for the DWMAC (and derivatives) bindings,
phy-connection-type was required, even though the previous binding required
the equivalent phy-mode.
Let's fix this by using phy-mode as we should have.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Both the allwinner and amlogic compatibles require that either the
allwinner,pipeline or the amlogic,pipeline property is set. This was
dropped during the conversion since we didn't have conditionals back then,
but we can express this properly now.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
The simple-framebuffer binding has a compatible that isn't one of the valid
options. Since an Allwinner pipeline is being described, let's add the
matching compatible.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
The child nodes of a mdio bus are supposed to be ethernet PHYs, with a reg
property. Make sure that's validated as well.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
MDIO controllers should have child nodes with a singe value in their reg
properties being the ID of the PHY in the bus.
Let's add the proper constraints on #address-cells and #size-cells.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
The node name of an MDIO controller should be MDIO. Let's add a rule for
this.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Based on the following report from Smatch, fix the potential
NULL pointer dereference check.
The patch 743256e214e8: "coresight: tmc: Clean up device specific
data" from May 22, 2019, leads to the following Smatch complaint:
drivers/hwtracing/coresight/coresight-tmc-etr.c:625 tmc_etr_free_flat_buf()
warn: variable dereferenced before check 'flat_buf' (see line 623)
drivers/hwtracing/coresight/coresight-tmc-etr.c
622 struct etr_flat_buf *flat_buf = etr_buf->private;
623 struct device *real_dev = flat_buf->dev->parent;
^^^^^^^^^^
The patch introduces a new NULL check
624
625 if (flat_buf && flat_buf->daddr)
^^^^^^^^
but the existing code assumed it can be NULL.
626 dma_free_coherent(real_dev, flat_buf->size,
627 flat_buf->vaddr, flat_buf->daddr);
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20190621175205.24551-3-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Based on the following report from Smatch tool, make sure we have a
valid drvdata before we dereference it to find the real dev.
The patch 21d26b905c05: "coresight: etm: Clean up device specific
data" from May 22, 2019, leads to the following Smatch complaint:
./drivers/hwtracing/coresight/coresight-etm3x.c:460 etm_get_trace_id()
warn: variable dereferenced before check 'drvdata' (see line 458)
./drivers/hwtracing/coresight/coresight-etm3x.c
457 int trace_id = -1;
458 struct device *etm_dev = drvdata->csdev->dev.parent;
^^^^^^^^^
New dereference
459
460 if (!drvdata)
^^^^^^^^
Checked too late. Delete the check?
461 goto out;
462
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20190621175205.24551-2-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During a perf session we try to allocate buffers on the "node" associated
with the CPU the event is bound to. If it is not bound to a CPU, we
use the current CPU node, using smp_processor_id(). However this is unsafe
in a pre-emptible context and could generate the splats as below :
BUG: using smp_processor_id() in preemptible [00000000] code: perf/2544
Use NUMA_NO_NODE hint instead of using the current node for events
not bound to CPUs.
Fixes: 2997aa4063 ("coresight: etb10: implementing AUX API")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: stable <stable@vger.kernel.org> # 4.6+
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20190620221237.3536-5-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During a perf session we try to allocate buffers on the "node" associated
with the CPU the event is bound to. If it is not bound to a CPU, we
use the current CPU node, using smp_processor_id(). However this is unsafe
in a pre-emptible context and could generate the splats as below :
BUG: using smp_processor_id() in preemptible [00000000] code: perf/2544
caller is tmc_alloc_etf_buffer+0x5c/0x60
CPU: 2 PID: 2544 Comm: perf Not tainted 5.1.0-rc6-147786-g116841e #344
Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb 1 2019
Call trace:
dump_backtrace+0x0/0x150
show_stack+0x14/0x20
dump_stack+0x9c/0xc4
debug_smp_processor_id+0x10c/0x110
tmc_alloc_etf_buffer+0x5c/0x60
etm_setup_aux+0x1c4/0x230
rb_alloc_aux+0x1b8/0x2b8
perf_mmap+0x35c/0x478
mmap_region+0x34c/0x4f0
do_mmap+0x2d8/0x418
vm_mmap_pgoff+0xd0/0xf8
ksys_mmap_pgoff+0x88/0xf8
__arm64_sys_mmap+0x28/0x38
el0_svc_handler+0xd8/0x138
el0_svc+0x8/0xc
Use NUMA_NO_NODE hint instead of using the current node for events
not bound to CPUs.
Fixes: 2e499bbc1a ("coresight: tmc: implementing TMC-ETF AUX space API")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: stable <stable@vger.kernel.org> # 4.7+
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20190620221237.3536-4-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During a perf session we try to allocate buffers on the "node" associated
with the CPU the event is bound to. If it is not bound to a CPU, we
use the current CPU node, using smp_processor_id(). However this is unsafe
in a pre-emptible context and could generate the splats as below :
BUG: using smp_processor_id() in preemptible [00000000] code: perf/1743
caller is tmc_alloc_etr_buffer+0x1bc/0x1f0
CPU: 1 PID: 1743 Comm: perf Not tainted 5.1.0-rc6-147786-g116841e #344
Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb 1 2019
Call trace:
dump_backtrace+0x0/0x150
show_stack+0x14/0x20
dump_stack+0x9c/0xc4
debug_smp_processor_id+0x10c/0x110
tmc_alloc_etr_buffer+0x1bc/0x1f0
etm_setup_aux+0x1c4/0x230
rb_alloc_aux+0x1b8/0x2b8
perf_mmap+0x35c/0x478
mmap_region+0x34c/0x4f0
do_mmap+0x2d8/0x418
vm_mmap_pgoff+0xd0/0xf8
ksys_mmap_pgoff+0x88/0xf8
__arm64_sys_mmap+0x28/0x38
el0_svc_handler+0xd8/0x138
el0_svc+0x8/0xc
Use NUMA_NO_NODE hint instead of using the current node for events
not bound to CPUs.
Fixes: 22f429f19c ("coresight: etm-perf: Add support for ETR backend")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: stable <stable@vger.kernel.org> # 4.20+
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20190620221237.3536-3-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During a perf session we try to allocate buffers on the "node" associated
with the CPU the event is bound to. If it's not bound to a CPU, we use
the current CPU node, using smp_processor_id(). However this is unsafe
in a pre-emptible context and could generate the splats as below :
BUG: using smp_processor_id() in preemptible [00000000] code: perf/1743
caller is alloc_etr_buf.isra.6+0x80/0xa0
CPU: 1 PID: 1743 Comm: perf Not tainted 5.1.0-rc6-147786-g116841e #344
Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb 1 2019
Call trace:
dump_backtrace+0x0/0x150
show_stack+0x14/0x20
dump_stack+0x9c/0xc4
debug_smp_processor_id+0x10c/0x110
alloc_etr_buf.isra.6+0x80/0xa0
tmc_alloc_etr_buffer+0x12c/0x1f0
etm_setup_aux+0x1c4/0x230
rb_alloc_aux+0x1b8/0x2b8
perf_mmap+0x35c/0x478
mmap_region+0x34c/0x4f0
do_mmap+0x2d8/0x418
vm_mmap_pgoff+0xd0/0xf8
ksys_mmap_pgoff+0x88/0xf8
__arm64_sys_mmap+0x28/0x38
el0_svc_handler+0xd8/0x138
el0_svc+0x8/0xc
Use NUMA_NO_NODE hint instead of using the current node for events
not bound to CPUs.
Fixes: 855ab61c16 ("coresight: tmc-etr: Refactor function tmc_etr_setup_perf_buf()")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190620221237.3536-2-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Daniel Borkmann says:
====================
pull-request: bpf 2019-07-03
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) Fix the interpreter to properly handle BPF_ALU32 | BPF_ARSH
on BE architectures, from Jiong.
2) Fix several bugs in the x32 BPF JIT for handling shifts by 0,
from Luke and Xi.
3) Fix NULL pointer deref in btf_type_is_resolve_source_only(),
from Stanislav.
4) Properly handle the check that forwarding is enabled on the device
in bpf_ipv6_fib_lookup() helper code, from Anton.
5) Fix UAPI bpf_prog_info fields alignment for archs that have 16 bit
alignment such as m68k, from Baruch.
6) Fix kernel hanging in unregister_netdevice loop while unregistering
device bound to XDP socket, from Ilya.
7) Properly terminate tail update in xskq_produce_flush_desc(), from Nathan.
8) Fix broken always_inline handling in test_lwt_seg6local, from Jiri.
9) Fix bpftool to use correct argument in cgroup errors, from Jakub.
10) Fix detaching dummy prog in XDP redirect sample code, from Prashant.
11) Add Jonathan to AF_XDP reviewers, from Björn.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The hip07 chip support vlan TSO, this patch adds NETIF_F_TSO
and NETIF_F_TSO6 flags to vlan_features to improve the
performance after adding vlan to the net ports.
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now all ctrl chunks are counted for asoc stats.octrlchunks and net
SCTP_MIB_OUTCTRLCHUNKS either after queuing up or bundling, other
than the chunk maked and bundled in sctp_packet_bundle_sack, which
caused 'outctrlchunks' not consistent with 'inctrlchunks' in peer.
This issue exists since very beginning, here to fix it by increasing
both net SCTP_MIB_OUTCTRLCHUNKS and asoc stats.octrlchunks when sack
chunk is maked and bundled in sctp_packet_bundle_sack.
Reported-by: Ja Ram Jeon <jajeon@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The variable err is being initialized with a value that is never
read and it is being updated later with a new value. The
initialization is redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The variable tpd_req is being initialized with a value that is never
read and it is being updated later with a new value. The
initialization is redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
r8153b_rx_agg_chg_indicate() needs to be called after enabling TX/RX and
before calling rxdy_gated_en(tp, false). Otherwise, the change of the
settings of RX aggregation wouldn't work.
Besides, adjust rtl8152_set_coalesce() for the same reason. If
rx_coalesce_usecs is changed, restart TX/RX to let the setting work.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds driver changes to detect/timestamp the unicast PTP packets.
Changes from previous version:
-------------------------------
v2: Defined a macro for unicast ptp param mask.
Please consider applying this to "net-next".
Signed-off-by: Sudarsana Reddy Kalluru <skalluru@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
u64_stats_fetch_begin needs to initialize start.
Signed-off-by: Catherine Sullivan <csully@google.com>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If IPV6 was disabled, then ss command would cause a kernel warning
because the command was attempting to dump IPV6 socket information.
The fix is to just remove the warning.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202249
Fixes: 432490f9d4 ("net: ip, diag -- Add diag interface for raw sockets")
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently during dual port IB device registration in below code flow,
ib_register_device()
ib_device_register_sysfs()
ib_setup_port_attrs()
add_port()
get_counter_table()
get_perf_mad()
process_mad()
mlx5_ib_process_mad()
mlx5_ib_process_mad() fails on 2nd port when both the ports are not fully
setup at the device level (because 2nd port is unaffiliated).
As a result, get_perf_mad() registers different PMA counter group for 1st
and 2nd port, namely pma_counter_ext and pma_counter. However both ports
have the same capability and counter offsets.
Due to this when counters are read by the user via sysfs in below code
flow, counters are queried from wrong location from the device mainly from
PPCNT instead of VPORT counters.
show_pma_counter()
get_perf_mad()
process_mad()
mlx5_ib_process_mad()
process_pma_cmd()
This shows all zero counters for 2nd port.
To overcome this, process_pma_cmd() is invoked, and when unaffiliated port
is not yet setup during device registration phase, make the query on the
first port. while at it, only process_pma_cmd() needs to work on the
native port number and underlying mdev, so shift the get, put calls to
where its needed inside process_pma_cmd().
Fixes: 212f2a87b7 ("IB/mlx5: Route MADs for dual port RoCE")
Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Expose an extra device definitions for objects events.
It includes: object_type values for legacy objects and generic data
header for any other object.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Report a CQ error event only when a handler was set.
This enables mlx5_ib to not set a handler upon CQ creation and use some
other mechanism to get this event as of other events by the
mlx5_eq_notifier_register API.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Enhance mlx5_core_create_cq() to get the command out buffer from the
callers to let them use the output.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Current driver checks if input bitstream file size is aligned or
not per PR data width (default 32bits). It requires one additional
step for end user when they generate the bitstream file, padding
extra zeros to bitstream file to align its size per PR data width,
but they don't have to as hardware will drop extra padding bytes
automatically.
In order to simplify the user steps, this patch aligns PR buffer
size per PR data width in driver, to allow user to pass unaligned
size bitstream files to driver.
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Link: https://lore.kernel.org/r/20190628004951.6202-4-mdf@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Expose the API to register for ANY event, mlx5_ib will be able to use
this functionality for its needs.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Use the reported device capabilities for the supported user events (i.e.
affiliated and un-affiliated) to set the EQ mask.
As the event mask can be up to 256 defined by 4 entries of u64 change
the applicable code to work accordingly.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
The firmware command to destroy a CQ might fail when the object is
referenced by other object and the ref count is managed by the firmware.
To enable a second successful destruction post the first failure need to
change mlx5_eq_del_cq() to be a void function.
As an error in mlx5_eq_del_cq() is quite fatal from the option to
recover, a debug message inside it should be good enougth and it was
changed to be void.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Fixes gcc '-Wunused-but-set-variable' warning:
drivers/infiniband/hw/hns/hns_roce_hw_v2.c: In function 'hns_roce_function_clear':
drivers/infiniband/hw/hns/hns_roce_hw_v2.c:1135:7: warning:
variable 'fclr_write_fail_flag' set but not used [-Wunused-but-set-variable]
It is never used, so can be removed.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
The API for ib_query_qp requires the driver to set qp_state and
cur_qp_state on return, add the missing sets.
Fixes: d374984179 ("i40iw: add files for iwarp interface")
Signed-off-by: Changcheng Liu <changcheng.liu@aliyun.com>
Acked-by: Shiraz Saleem <shiraz.saleem@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
When uart_flush_buffer() is called, the .flush_buffer() callback zeroes
the tx_dma_len field. This may race with the work queue function
handling transmit DMA requests:
1. If the buffer is flushed before the first DMA API call,
dmaengine_prep_slave_single() may be called with a zero length,
causing the DMA request to never complete, leading to messages
like:
rcar-dmac e7300000.dma-controller: Channel Address Error happen
and, with debug enabled:
sh-sci e6e88000.serial: sci_dma_tx_work_fn: ffff800639b55000: 0...0, cookie 126
and DMA timeouts.
2. If the buffer is flushed after the first DMA API call, but before
the second, dma_sync_single_for_device() may be called with a zero
length, causing the transmit data not to be flushed to RAM, and
leading to stale data being output.
Fix this by:
1. Letting sci_dma_tx_work_fn() return immediately if the transmit
buffer is empty,
2. Extending the critical section to cover all DMA preparational work,
so tx_dma_len stays consistent for all of it,
3. Using local copies of circ_buf.head and circ_buf.tail, to make sure
they match the actual operation above.
Reported-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Suggested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Link: https://lore.kernel.org/r/20190624123540.20629-2-geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
