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2016-08-09cxl: Use fixed width predefined types in data structure.Philippe Bergheaud
This patch fixes a regression introduced by commit b810253bd934 ("cxl: Add mechanism for delivering AFU driver specific events"). It changes the type u8 to __u8 in the uapi header cxl.h, because the former is a kernel internal type, and may not be defined in userland build environments, in particular when cross-compiling libcxl on x86_64 linux machines (RHEL6.7 and Ubuntu 16.04). This patch also changes the size of the field data_size, and makes it constant, to support 32-bit userland applications running on big-endian ppc64 kernels transparently. mpe: This is an ABI change, however the ABI was only added during the 4.8 merge window so has never been part of a released kernel - therefore we give ourselves permission to change it. Fixes: b810253bd934 ("cxl: Add mechanism for delivering AFU driver specific events") Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com> Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-06-28cxl: Add mechanism for delivering AFU driver specific eventsPhilippe Bergheaud
This adds an afu_driver_ops structure with fetch_event() and event_delivered() callbacks. An AFU driver such as cxlflash can fill this out and associate it with a context to enable passing custom AFU specific events to userspace. This also adds a new kernel API function cxl_context_pending_events(), that the AFU driver can use to notify the cxl driver that new specific events are ready to be delivered, and wake up anyone waiting on the context wait queue. The current count of AFU driver specific events is stored in the field afu_driver_events of the context structure. The cxl driver checks the afu_driver_events count during poll, select, read, etc. calls to check if an AFU driver specific event is pending, and calls fetch_event() to obtain and deliver that event. This way, the cxl driver takes care of all the usual locking semantics around these calls and handles all the generic cxl events, so that the AFU driver only needs to worry about it's own events. fetch_event() return a struct cxl_event_afu_driver_reserved, allocated by the AFU driver, and filled in with the specific event information and size. Total event size (header + data) should not be greater than CXL_READ_MIN_SIZE (4K). Th cxl driver prepends an appropriate cxl event header, copies the event to userspace, and finally calls event_delivered() to return the status of the operation to the AFU driver. The event is identified by the context and cxl_event_afu_driver_reserved pointers. Since AFU drivers provide their own means for userspace to obtain the AFU file descriptor (i.e. cxlflash uses an ioctl on their scsi file descriptor to obtain the AFU file descriptor) and the generic cxl driver will never use this event, the ABI of the event is up to each individual AFU driver. Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-03-09cxl: Support to flash a new image on the adapter from a guestChristophe Lombard
The new flash.c file contains the logic to flash a new image on the adapter, through a hcall. It is an iterative process, with chunks of data of 1M at a time. There are also 2 phases: write and verify. The flash operation itself is driven from a user-land tool. Once flashing is successful, an rtas call is made to update the device tree with the new properties values for the adapter and the AFU(s) Add a new char device for the adapter, so that the flash tool can access the card, even if there is no valid AFU on it. Co-authored-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Reviewed-by: Manoj Kumar <manoj@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-08-18cxl: Add alternate MMIO error handlingIan Munsie
userspace programs using cxl currently have to use two strategies for dealing with MMIO errors simultaneously. They have to check every read for a return of all Fs in case the adapter has gone away and the kernel has not yet noticed, and they have to deal with SIGBUS in case the kernel has already noticed, invalidated the mapping and marked the context as failed. In order to simplify things, this patch adds an alternative approach where the kernel will return a page filled with Fs instead of delivering a SIGBUS. This allows userspace to only need to deal with one of these two error paths, and is intended for use in libraries that use cxl transparently and may not be able to safely install a signal handler. This approach will only work if certain constraints are met. Namely, if the application is both reading and writing to an address in the problem state area it cannot assume that a non-FF read is OK, as it may just be reading out a value it has previously written. Further - since only one page is used per context a write to a given offset would be visible when reading the same offset from a different page in the mapping (this only applies within a single context, not between contexts). An application could deal with this by e.g. making sure it also reads from a read-only offset after any reads to a read/write offset. Due to these constraints, this functionality must be explicitly requested by userspace when starting the context by passing in the CXL_START_WORK_ERR_FF flag. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Acked-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-03cxl: Implement an ioctl to fetch afu card-id, offset-id and modeVaibhav Jain
Given a file descriptor on an afu device, libcxl currently uses the major/minor number obtained from fstat on the fd to construct path to the afu's sysfs directory. However it is possible that rather than using one of the device in /dev/cxl, a kernel driver creates its own device which export generic cxl interface to the userspace. This causes problems with libcxl as it tries to use a wrong major/minor number to construct the sysfs path and fail. So this patch introduces a new ioctl called CXL_IOCTL_GET_AFU_ID on the afu file descriptor to fetch the cxl_afu_id struct that holds the card/offset-id and mode information. These info is then used by libcxl to construct the correct path to the afu sysfs directory. Testing: - Build against pseries be/le configs - Testing with corresponding libcxl changes to verify that it constructs right sysfs path to the afu. Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-08cxl: Add documentation for userspace APIsIan Munsie
This documentation gives an overview of the hardware architecture, userspace APIs via /dev/cxl/afuM.N and the syfs files. It also adds a MAINTAINERS file entry for cxl. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-08cxl: Add userspace header fileIan Munsie
This adds a header file for use by userspace programs wanting to interact with the kernel cxl driver. It defines structs and magic numbers required for userspace to interact with devices in /dev/cxl/afuM.N. Further documentation on this interface is added in a subsequent patch in Documentation/powerpc/cxl.txt. It also adds this new userspace header file to Kbuild so it's exported when doing "make headers_installs". Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>