usb: wusbcore: convert nested lock to use spin_lock instead of spin_lock_irq

Nesting a spin_lock_irq/unlock_irq inside a lock that has already
disabled interrupts will enable interrupts before we are ready when
spin_unlock_irq is called.  This patch converts the inner lock to use
spin_lock and spin_unlock instead.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: wusbcore: fix panic in wusbhc_chid_set

If no valid CHID value has previously been set on an HWA, writing a
value of all zeros will cause a kernel panic in uwb_radio_stop because
wusbhc->uwb_rc has not been set.  This patch skips the call to
uwb_radio_stop if wusbhc->uwb_rc has not been initialized.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: serial: fix sysfs-attribute removal deadlock

Fix driver new_id sysfs-attribute removal deadlock by making sure to
not hold any locks that the attribute operations grab when removing the
attribute.

Specifically, usb_serial_deregister holds the table mutex when
deregistering the driver, which includes removing the new_id attribute.
This can lead to a deadlock as writing to new_id increments the
attribute's active count before trying to grab the same mutex in
usb_serial_probe.

The deadlock can easily be triggered by inserting a sleep in
usb_serial_deregister and writing the id of an unbound device to new_id
during module unload.

As the table mutex (in this case) is used to prevent subdriver unload
during probe, it should be sufficient to only hold the lock while
manipulating the usb-serial driver list during deregister. A racing
probe will then either fail to find a matching subdriver or fail to get
the corresponding module reference.

Since v3.15-rc1 this also triggers the following lockdep warning:

======================================================
[ INFO: possible circular locking dependency detected ]
3.15.0-rc2 #123 Tainted: G        W
-------------------------------------------------------
modprobe/190 is trying to acquire lock:
 (s_active#4){++++.+}, at: [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94

but task is already holding lock:
 (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (table_lock){+.+.+.}:
       [<c0075f84>] __lock_acquire+0x1694/0x1ce4
       [<c0076de8>] lock_acquire+0xb4/0x154
       [<c03af3cc>] _raw_spin_lock+0x4c/0x5c
       [<c02bbc24>] usb_store_new_id+0x14c/0x1ac
       [<bf007eb4>] new_id_store+0x68/0x70 [usbserial]
       [<c025f568>] drv_attr_store+0x30/0x3c
       [<c01690e0>] sysfs_kf_write+0x5c/0x60
       [<c01682c0>] kernfs_fop_write+0xd4/0x194
       [<c010881c>] vfs_write+0xbc/0x198
       [<c0108e4c>] SyS_write+0x4c/0xa0
       [<c000f880>] ret_fast_syscall+0x0/0x48

-> #0 (s_active#4){++++.+}:
       [<c03a7a28>] print_circular_bug+0x68/0x2f8
       [<c0076218>] __lock_acquire+0x1928/0x1ce4
       [<c0076de8>] lock_acquire+0xb4/0x154
       [<c0166b70>] __kernfs_remove+0x254/0x310
       [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94
       [<c0169fb8>] remove_files.isra.1+0x48/0x84
       [<c016a2fc>] sysfs_remove_group+0x58/0xac
       [<c016a414>] sysfs_remove_groups+0x34/0x44
       [<c02623b8>] driver_remove_groups+0x1c/0x20
       [<c0260e9c>] bus_remove_driver+0x3c/0xe4
       [<c026235c>] driver_unregister+0x38/0x58
       [<bf007fb4>] usb_serial_bus_deregister+0x84/0x88 [usbserial]
       [<bf004db4>] usb_serial_deregister+0x6c/0x78 [usbserial]
       [<bf005330>] usb_serial_deregister_drivers+0x2c/0x4c [usbserial]
       [<bf016618>] usb_serial_module_exit+0x14/0x1c [sierra]
       [<c009d6cc>] SyS_delete_module+0x184/0x210
       [<c000f880>] ret_fast_syscall+0x0/0x48

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(table_lock);
                               lock(s_active#4);
                               lock(table_lock);
  lock(s_active#4);

 *** DEADLOCK ***

1 lock held by modprobe/190:
 #0:  (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial]

stack backtrace:
CPU: 0 PID: 190 Comm: modprobe Tainted: G        W     3.15.0-rc2 #123
[<c0015e10>] (unwind_backtrace) from [<c0013728>] (show_stack+0x20/0x24)
[<c0013728>] (show_stack) from [<c03a9a54>] (dump_stack+0x24/0x28)
[<c03a9a54>] (dump_stack) from [<c03a7cac>] (print_circular_bug+0x2ec/0x2f8)
[<c03a7cac>] (print_circular_bug) from [<c0076218>] (__lock_acquire+0x1928/0x1ce4)
[<c0076218>] (__lock_acquire) from [<c0076de8>] (lock_acquire+0xb4/0x154)
[<c0076de8>] (lock_acquire) from [<c0166b70>] (__kernfs_remove+0x254/0x310)
[<c0166b70>] (__kernfs_remove) from [<c0167aa0>] (kernfs_remove_by_name_ns+0x4c/0x94)
[<c0167aa0>] (kernfs_remove_by_name_ns) from [<c0169fb8>] (remove_files.isra.1+0x48/0x84)
[<c0169fb8>] (remove_files.isra.1) from [<c016a2fc>] (sysfs_remove_group+0x58/0xac)
[<c016a2fc>] (sysfs_remove_group) from [<c016a414>] (sysfs_remove_groups+0x34/0x44)
[<c016a414>] (sysfs_remove_groups) from [<c02623b8>] (driver_remove_groups+0x1c/0x20)
[<c02623b8>] (driver_remove_groups) from [<c0260e9c>] (bus_remove_driver+0x3c/0xe4)
[<c0260e9c>] (bus_remove_driver) from [<c026235c>] (driver_unregister+0x38/0x58)
[<c026235c>] (driver_unregister) from [<bf007fb4>] (usb_serial_bus_deregister+0x84/0x88 [usbserial])
[<bf007fb4>] (usb_serial_bus_deregister [usbserial]) from [<bf004db4>] (usb_serial_deregister+0x6c/0x78 [usbserial])
[<bf004db4>] (usb_serial_deregister [usbserial]) from [<bf005330>] (usb_serial_deregister_drivers+0x2c/0x4c [usbserial])
[<bf005330>] (usb_serial_deregister_drivers [usbserial]) from [<bf016618>] (usb_serial_module_exit+0x14/0x1c [sierra])
[<bf016618>] (usb_serial_module_exit [sierra]) from [<c009d6cc>] (SyS_delete_module+0x184/0x210)
[<c009d6cc>] (SyS_delete_module) from [<c000f880>] (ret_fast_syscall+0x0/0x48)

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
phy: exynos: fix building as a module

The top-level phy-samsung-usb2 driver may be configured as a
loadable module, which currently causes link errors because
of the dependency on the exynos{5250,4x12,4210}_usb2_phy_config
symbol. Solving this could be achieved by exporting these
symbols, but as the SoC-specific parts of the driver are not
currently built as modules, it seems better to just link
everything into one module and avoid the need for the export.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
phy: restore OMAP_CONTROL_PHY dependencies

When OMAP_CONTROL_USB was renamed to OMAP_CONTROL_PHY (commit
14da699b), its dependencies were lost in the process. Nothing in the
commit message indicates that this removal was intentional, so I think
it was by accident and the dependencies should be restored.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Roger Quadros <rogerq@ti.com>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
phy: fix kernel oops in phy_lookup()

The kernel oopses in phy_lookup() due to 'phy->init_data' being NULL if we
register PHYs from a device tree probing driver and then call phy_get() on a
device that has no representation in the device tree (e.g. a PCI device).
Checking the pointer before dereferening it and skipping an interation if
it's NULL prevents this kernel oops.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
phy: core: make NULL a valid phy reference if !CONFIG_GENERIC_PHY

This fixes a regression on Keystone 2 platforms caused by patch
57303488cd37da58263e842de134dc65f7c626d5
"usb: dwc3: adapt dwc3 core to use Generic PHY Framework" which adds
optional support of generic phy in DWC3 core.

On Keystone 2 platforms the USB is not working now because
CONFIG_GENERIC_PHY isn't set and, as result, Generic PHY APIs stubs
return -ENOSYS always. The log shows:
 dwc3 2690000.dwc3: failed to initialize core
 dwc3: probe of 2690000.dwc3 failed with error -38

Hence, fix it by making NULL a valid phy reference in Generic PHY
APIs stubs in the same way as it was done by the patch
04c2facad8fee66c981a51852806d8923336f362 "drivers: phy: Make NULL
a valid phy reference".

Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
can: c_can_pci: Set the type of the IP core

All type checks in c_can.c are != BOSCH_D_CAN so nobody noticed so far
that the pci code does not update the type information.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Fix startup logic

c_can_start() enables interrupts way too early. The first enabling
happens when setting the control mode in c_can_chip_config() and then
again at the end of the function.

But that happens before napi_enable() and that means that an interrupt
which comes in will disable interrupts again and call napi_schedule,
which ignores the request and the later napi_enable() is not making
thinks work either. So the interface is up with all device interrupts
disabled.

Move the device interrupt after napi_enable() and add it to the other
callsites of c_can_start() in c_can_set_mode() and c_can_power_up()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Make bus off interrupt disable logic work

The state change handler is called with device interrupts disabled
already. So no point in disabling them again when we enter bus off
state.

But what's worse is that we reenable the interrupts at the end of NAPI
poll unconditionally. So c_can_start() which is called from the
restart timer can trigger interrupts which confuse the hell out of the
half reinitialized driver/hw.

Remove the pointless device interrupt disable in the BUS_OFF handler
and prevent reenabling the device interrupts at the end of the poll
routine when the current state is BUS_OFF.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Do not access skb after net_receive_skb()

There is no guarantee that the skb is in the same state after calling
net_receive_skb(). It might be freed or reused. Not really harmful as
its a read access, except you turn on the proper debugging options
which catch a use after free.

The whole can subsystem is full of this. Copy and paste ....

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Handle state change correctly

If the allocation of an error skb fails, the state change handling
returns w/o doing any work. That leaves the interface in a wreckaged
state as the internal status is wrong.

Split the interface handling and the skb handling.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Fix berr reporting

Reading the LEC type with

  return (mode & ENABLED) && (status & LEC_MASK);

is not guaranteed to return (status & LEC_MASK) if the enabled bit in
mode is set. It's guaranteed to return 0 or !=0.

Remove the inline function and call unconditionally into the
berr_handling code and return early when the reporting is disabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Always update error stats

If the allocation of the error skb fails, we still want to see the
error statistics.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Simplify buffer reenabling

Instead of writing to the message object we can simply clear the
NewDat bit with the get method.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Avoid status register update for D_CAN

On D_CAN the RXOK, TXOK and LEC bits are cleared/set on read of the
status register. No need to update them.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Get rid of pointless interrupts

The driver handles pointlessly TWO interrupts per packet. The reason
is that it enables the status interrupt which fires for each rx and tx
packet and it enables the per message object interrupts as well.

The status interrupt merily acks or in case of D_CAN ignores the TX/RX
state and then the message object interrupt fires.

The message objects interrupts are only useful if all message objects
have hardware filters activated.

But we don't have that and its not simple to implement in that driver
without rewriting it completely.

So we can ditch the message object interrupts and handle the RX/TX
right away from the status interrupt. Instead of TWO we handle ONE.

Note: We must keep the TXIE/RXIE bits in the message buffers because
the status interrupt alone is not reliable enough in corner cases.

If we ever have the need for HW filtering, then this code needs a
complete overhaul and we can think about it then. For now we prefer a
lower interrupt load.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Disable rx split as workaround

The RX buffer split causes packet loss in the hardware:

What happens is:

RX Packet 1 --> message buffer 1 (newdat bit is not cleared)
RX Packet 2 --> message buffer 2 (newdat bit is not cleared)
RX Packet 3 --> message buffer 3 (newdat bit is not cleared)
RX Packet 4 --> message buffer 4 (newdat bit is not cleared)
RX Packet 5 --> message buffer 5 (newdat bit is not cleared)
RX Packet 6 --> message buffer 6 (newdat bit is not cleared)
RX Packet 7 --> message buffer 7 (newdat bit is not cleared)
RX Packet 8 --> message buffer 8 (newdat bit is not cleared)

Clear newdat bit in message buffer 1
Clear newdat bit in message buffer 2
Clear newdat bit in message buffer 3
Clear newdat bit in message buffer 4
Clear newdat bit in message buffer 5
Clear newdat bit in message buffer 6
Clear newdat bit in message buffer 7
Clear newdat bit in message buffer 8

Now if during that clearing of newdat bits, a new message comes in,
the HW gets confused and drops it.

It does not matter how many of them you clear. I put a delay between
clear of buffer 1 and buffer 2 which was long enough that the message
should have been queued either in buffer 1 or buffer 9. But it did not
show up anywhere. The next message ended up in buffer 1. So the
hardware lost a packet of course without telling it via one of the
error handlers.

That does not happen on all clear newdat bit events. I see one of 10k
packets dropped in the scenario which allows us to reproduce. But the
trace looks always the same.

Not splitting the RX Buffer avoids the packet loss but can cause
reordering. It's hard to trigger, but it CAN happen.

With that mode we use the HW as it was probably designed for. We read
from the buffer 1 upwards and clear the buffer as we get the
message. That's how all microcontrollers use it. So I assume that the
way we handle the buffers was never really tested. According to the
public documentation it should just work :)

Let the user decide which evil is the lesser one.

[ Oliver Hartkopp: Provided a sane config option and help text and
  made me switch to favour potential and unlikely reordering over
  packet loss ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Work around C_CAN RX wreckage

Alexander reported that the new optimized handling of the RX fifo
causes random packet loss on Intel PCH C_CAN hardware.

After a few fruitless debugging sessions I got hold of a PCH (eg20t)
afflicted system. That machine does not have the CAN interface wired
up, but it was possible to reproduce the issue with the HW loopback
mode.

As Alexander observed correctly, clearing the NewDat flag along with
reading out the message buffer causes that issue on C_CAN, while D_CAN
handles that correctly.

Instead of restoring the original message buffer handling horror the
following workaround solves the issue:

    transfer buffer to IF without clearing the NewDat
    handle the message
    clear NewDat bit

That's similar to the original code but conditional for C_CAN.

I really wonder why all user manuals (C_CAN, Intel PCH and some more)
recommend to clear the NewDat bit right away. The knows it all Oracle
operated by Gurgle does not unearth any useful information either. I
simply cannot believe that we are the first to uncover that HW issue.

Reported-and-tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: c_can: Cleanup irq enable/disable

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>