- 21 Mar, 2017 1 commit
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Logan Gunthorpe authored
Credit for this patch goes is shared with Dan Williams [1]. I've taken things one step further to make the helper function more useful and clean up calling code. There's a common pattern in the kernel whereby a struct cdev is placed in a structure along side a struct device which manages the life-cycle of both. In the naive approach, the reference counting is broken and the struct device can free everything before the chardev code is entirely released. Many developers have solved this problem by linking the internal kobjs in this fashion: cdev.kobj.parent = &parent_dev.kobj; The cdev code explicitly gets and puts a reference to it's kobj parent. So this seems like it was intended to be used this way. Dmitrty Torokhov first put this in place in 2012 with this commit: 2f0157f1 char_dev: pin parent kobject and the first instance of the fix was then done in the input subsystem in the following commit: 4a215aad Input: fix use-after-free introduced with dynamic minor changes Subsequently over the years, however, this issue seems to have tripped up multiple developers independently. For example, see these commits: 0d5b7dae iio: Prevent race between IIO chardev opening and IIO device (by Lars-Peter Clausen in 2013) ba0ef854 tpm: Fix initialization of the cdev (by Jason Gunthorpe in 2015) 5b28dde5 [media] media: fix use-after-free in cdev_put() when app exits after driver unbind (by Shauh Khan in 2016) This technique is similarly done in at least 15 places within the kernel and probably should have been done so in another, at least, 5 places. The kobj line also looks very suspect in that one would not expect drivers to have to mess with kobject internals in this way. Even highly experienced kernel developers can be surprised by this code, as seen in [2]. To help alleviate this situation, and hopefully prevent future wasted effort on this problem, this patch introduces a helper function to register a char device along with its parent struct device. This creates a more regular API for tying a char device to its parent without the developer having to set members in the underlying kobject. This patch introduce cdev_device_add and cdev_device_del which replaces a common pattern including setting the kobj parent, calling cdev_add and then calling device_add. It also introduces cdev_set_parent for the few cases that set the kobject parent without using device_add. [1] https://lkml.org/lkml/2017/2/13/700 [2] https://lkml.org/lkml/2017/2/10/370Signed-off-by:
Logan Gunthorpe <logang@deltatee.com> Signed-off-by:
Dan Williams <dan.j.williams@intel.com> Reviewed-by:
Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by:
Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 17 Mar, 2017 39 commits
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Geert Uytterhoeven authored
The Hitachi HD44780 Character LCD Controller is commonly used on character LCDs that can display one or more lines of text. This driver supports character LCDs connected to GPIOs, using either a 4-bit or 8-bit data bus, and provides access through the charlcd core and /dev/lcd. Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by:
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Geert Uytterhoeven authored
Add DT bindings for an Hitachi HD44780 Character LCD Controller where its M6800 bus interface is connected to GPIOs. Memory-mapped configurations are not yet supported. Signed-off-by:
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Geert Uytterhoeven authored
On displays with more than two lines, the additional lines are stored in the buffers used for the first two lines, but beyond the visible parts. Adjust the DDRAM address calculation to cater for this. When clearing the display, avoid writing more spaces than the actual size of the physical buffer. Signed-off-by:
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Geert Uytterhoeven authored
In 4-bit mode, 8-bit commands and data are written using two raw writes to the data interface: high nibble first, low nibble last. This must be handled by the low-level driver. However, as we don't know in which mode (4-bit or 8-bit) nor 4-bit phase the LCD was left, initialization must always be handled using raw writes, and needs to configure the LCD for 8-bit mode first. Signed-off-by:
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Geert Uytterhoeven authored
Extract the character LCD core from the Parallel port LCD/Keypad Panel driver in the misc subsystem, and convert it into a subdriver in the auxdisplay subsystem. This allows the character LCD core to be used by other drivers later. Compilation is controlled by its own Kconfig symbol CHARLCD, which is to be selected by its users, but can be enabled manually for compile-testing. All functions changed their prefix from "lcd_" to "charlcd_", and gained a "struct charlcd *" parameter to operate on a specific instance. While the driver API thus is ready to support multiple instances, the current limitation of a single display (/dev/lcd has a single misc minor assigned) is retained. No functional changes intended. Signed-off-by:
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Joe Perches authored
To enable eventual removal of pr_warning This makes pr_warn use consistent for drivers/char Prior to this patch, there were 1 use of pr_warning and 40 uses of pr_warn in drivers/char Signed-off-by:
Joe Perches <joe@perches.com> Reviewed-by:
Amit Shah <amit@kernel.org> Signed-off-by:
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Mariusz Bialonczyk authored
Signed-off-by:
Mariusz Bialonczyk <manio@skyboo.net> Signed-off-by:
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Mariusz Bialonczyk authored
Signed-off-by:
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Mariusz Bialonczyk authored
Detailed information about support and provided sysfs files in my next commit which creates a documentation file: Documentation/w1/slaves/w1_ds2438 Signed-off-by:
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Mariusz Bialonczyk authored
Signed-off-by:
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Matt Ranostay authored
Issue is that x86 32-bit aligns to 4-bytes instead of 8-bytes so this patchset works around the issue and corrects the data returned in pps_fdata_compat. Acked-by:
Rodolfo Giometti <giometti@enneenne.com> Signed-off-by:
Matt Ranostay <matt.ranostay@konsulko.com> Signed-off-by:
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Matt Ranostay authored
ioctl definitions use the pointer size of the architecture which is fine when userspace and kernel are the same bitsize. This patchset workarounds an issue with mixed bitsize kernel + userspace by rewriting the cmd to the kernelspace architecture pointer size. Acked-by:
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Martyn Welch authored
Update VME documentation given that kerneldoc comments are now provided. Add "VME API" section to VME RST to pull in kerneldoc comments. Signed-off-by:
Martyn Welch <martyn.welch@collabora.co.uk> Signed-off-by:
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Martyn Welch authored
Add kernel-doc comments to the VME driver API and structures. This documentation will be integrated into the RST documentation in a later patch. Signed-off-by:
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Matthias Kaehlcke authored
The value passed by the two callers of the function is unsigned anyway. Making the parameter unsigned fixes the following warning when building with clang: drivers/char/hpet.c:588:7: error: overflow converting case value to switch condition type (2149083139 to 18446744071563667459) [-Werror,-Wswitch] case HPET_INFO: ^ include/uapi/linux/hpet.h:18:19: note: expanded from macro 'HPET_INFO' ^ include/uapi/asm-generic/ioctl.h:77:28: note: expanded from macro '_IOR' ^ include/uapi/asm-generic/ioctl.h:66:2: note: expanded from macro '_IOC' (((dir) << _IOC_DIRSHIFT) | \ Signed-off-by:Matthias Kaehlcke <mka@chromium.org> Acked-by:
Clemens Ladisch <clemens@ladisch.de> Signed-off-by:
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Cyril Bur authored
In order to manage server systems, there is typically another processor known as a BMC (Baseboard Management Controller) which is responsible for powering the server and other various elements, sometimes fans, often the system flash. The Aspeed BMC family which is what is used on OpenPOWER machines and a number of x86 as well is typically connected to the host via an LPC (Low Pin Count) bus (among others). The LPC bus is an ISA bus on steroids. It's generally used by the BMC chip to provide the host with access to the system flash (via MEM/FW cycles) that contains the BIOS or other host firmware along with a number of SuperIO-style IOs (via IO space) such as UARTs, IPMI controllers. On the BMC chip side, this is all configured via a bunch of registers whose content is related to a given policy of what devices are exposed at a per system level, which is system/vendor specific, so we don't want to bolt that into the BMC kernel. This started with a need to provide something nicer than /dev/mem for user space to configure these things. One important aspect of the configuration is how the MEM/FW space is exposed to the host (ie, the x86 or POWER). Some registers in that bridge can define a window remapping all or portion of the LPC MEM/FW space to a portion of the BMC internal bus, with no specific limits imposed in HW. I think it makes sense to ensure that this window is configured by a kernel driver that can apply some serious sanity checks on what it is configured to map. In practice, user space wants to control this by flipping the mapping between essentially two types of portions of the BMC address space: - The flash space. This is a region of the BMC MMIO space that more/less directly maps the system flash (at least for reads, writes are somewhat more complicated). - One (or more) reserved area(s) of the BMC physical memory. The latter is needed for a number of things, such as avoiding letting the host manipulate the innards of the BMC flash controller via some evil backdoor, we want to do flash updates by routing the window to a portion of memory (under control of a mailbox protocol via some separate set of registers) which the host can use to write new data in bulk and then request the BMC to flash it. There are other uses, such as allowing the host to boot from an in-memory flash image rather than the one in flash (very handy for continuous integration and test, the BMC can just download new images). It is important to note that due to the way the Aspeed chip lets the kernel configure the mapping between host LPC addresses and BMC ram addresses the offset within the window must be a multiple of size. Not doing so will fragment the accessible space rather than simply moving 'zero' upwards. This is caused by the nature of HICR8 being a mask and the way host LPC addresses are translated. Signed-off-by:
Cyril Bur <cyrilbur@gmail.com> Reviewed-by:
Joel Stanley <joel@jms.id.au> Reviewed-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
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Dmitry Torokhov authored
Instead of creating attributes one by one, define attribute_group array and attach it to bus->dev_groups, so that all needed attributes are created automatically when a new device is registered on the bus. Also switch to using standard DEVICE_ATTR_RO() macros. Signed-off-by:
Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by:
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Ming Lei authored
This email of 'ming.lei@canonical.com' isn't valid any more, please remove the entry. Signed-off-by:
Ming Lei <tom.leiming@gmail.com> Signed-off-by:
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Dmitry Torokhov authored
Instead of creating switch-specific attributes by hand, implement is_visible() method of attribute group and hide them when dealing with non-switch devices. This will ensure that all attributes are created together, before userspace gets notified of new device. Also, remove rio-sysfs.c from list of files that are scanned when compiling RapiodIO documentations as it no longer has any structured comments, and leaving it in leads to warning when building docs. Signed-off-by:
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Rob Herring authored
As AOSP master is now starting to require a hwbinder device, add it to the the default Kconfig. Having the hwbinder device when not needed shouldn't hurt anything either. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Martijn Coenen <maco@google.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Amit Pundir <amit.pundir@linaro.org> Cc: Serban Constantinescu <serban.constantinescu@arm.com> Cc: Dmitry Shmidt <dimitrysh@google.com> Cc: Rom Lemarchand <romlem@google.com> Cc: Android Kernel Team <kernel-team@android.com> Signed-off-by:
Rob Herring <robh@kernel.org> Signed-off-by:
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K. Y. Srinivasan authored
Don't enable auto-eoi if the hypervisor recommends otherwise. This will enable vAPIC functionality if available. Signed-off-by:
K. Y. Srinivasan <kys@microsoft.com> Signed-off-by:
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K. Y. Srinivasan authored
Fix a typo in the macro. Signed-off-by:
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Stephen Hemminger authored
Allow driver to get debug information about state of the ring. Signed-off-by:
Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by:
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Stephen Hemminger authored
Minor changes to align hyper-v vmbus include files with current linux kernel style. Signed-off-by:
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Stephen Hemminger authored
This table is immutable and should be const. Cleanup indentation and whitespace for this as well. Signed-off-by:
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Stephen Hemminger authored
hv_ringbuffer_read cleanup. Signed-off-by:
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Stephen Hemminger authored
Several spelling errors in comments Signed-off-by:
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Stephen Hemminger authored
Don't initialize variables that are then set a few lines later. Signed-off-by:
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Stephen Hemminger authored
No need for empty return at end of void function Signed-off-by:
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Stephen Hemminger authored
Compiling with warnings enabled finds missing prototype for hv_do_hypercall. Signed-off-by:
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Stephen Hemminger authored
The change to reschedule tasklet if more data arrives in ring buffer can cause performance regression if host timing is such that the next response happens in small window. Go back to a modified version of the original looping behavior. If the race occurs in a small time, then loop. But if the tasklet has been running for a long interval due to flood, then reschedule the tasklet to allow migration to ksoftirqd. Signed-off-by:
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Moritz Fischer authored
Replaces open-coded list_for_each() + list_entry() with macro list_for_each_entry() Signed-off-by:
Moritz Fischer <mdf@kernel.org> Cc: linux-fpga@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by:
Alan Tull <atull@kernel.org> Signed-off-by:
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Joel Holdsworth authored
This patch adds support to the FPGA manager for configuring the SRAM of iCE40LM, iCE40LP, iCE40HX, iCE40 Ultra, iCE40 UltraLite and iCE40 UltraPlus devices, through slave SPI. Signed-off-by:
Joel Holdsworth <joel@airwebreathe.org.uk> Reviewed-by:
Marek Vasut <marex@denx.de> Reviewed-by:
Moritz Fischer <moritz.fischer@ettus.com> Acked-by:
Alan Tull <atull@opensource.altera.com> Signed-off-by:
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Joel Holdsworth authored
This adds documentation of the device tree bindings of the Lattice iCE40 FPGA driver for the FPGA manager framework. Signed-off-by:
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Florian Fainelli authored
Register the TS-7300 FPGA manager device drivers which allows us to load bitstreams into the on-board Altera Cyclone II FPGA. Acked-by:
H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by:
Florian Fainelli <f.fainelli@gmail.com> Acked-by:
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Florian Fainelli authored
Add support for loading bitstreams on the Altera Cyclone II FPGA populated on the TS-7300 board. This is done through the configuration and data registers offered through a memory interface between the EP93xx SoC and the FPGA via an intermediate CPLD device. The EP93xx SoC on the TS-7300 does not have direct means of configuring the on-board FPGA other than by using the special memory mapped interface to the CPLD. No other entity on the system can control the FPGA bitstream. Signed-off-by:
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Moritz Fischer authored
Add fpga-region property to allow passing the fact that the bitstream is encrypted to the fpga-region and ultimately to the low-level driver. Signed-off-by:
Michal Simek <michal.simek@xilinx.com> Signed-off-by:
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Moritz Fischer authored
Add support for encrypted bitstreams. For this to work the system must be booted in secure mode. In order for on-the-fly decryption to work, the PCAP clock rate needs to be lowered via the PCAP_RATE_EN bit. Signed-off-by:
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Moritz Fischer authored
Add a flag that is passed to the write_init() callback, indicating that the bitstream is encrypted. The low-level driver will deal with the flag, or return an error, if encrypted bitstreams are not supported. Signed-off-by:
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