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path: root/drivers/misc/cxl/pci.c
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* cxl: Workaround malformed pcie packets on some cardsPhilippe Bergheaud2015-10-06
| | | | | | | | | | | | This works around a pcie host bridge defect on some cards, that can cause malformed Transaction Layer Packet (TLP) errors to be erroneously reported. The upper nibble of the vendor section PSL revision is used to distinguish between different cards. The affected ones have it set to 0. Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Fix unbalanced pci_dev_get in cxl_probeDaniel Axtens2015-09-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the first thing we do in cxl_probe is to grab a reference on the pci device. Later on, we call device_register on our adapter. In our remove path, we call device_unregister, but we never call pci_dev_put. We therefore leak the device every time we do a reflash. device_register/unregister is sufficient to hold the reference. Therefore, drop the call to pci_dev_get. Here's why this is safe. The proposed cxl_probe(pdev) calls cxl_adapter_init: a) init calls cxl_adapter_alloc, which creates a struct cxl, conventionally called adapter. This struct contains a device entry, adapter->dev. b) init calls cxl_configure_adapter, where we set adapter->dev.parent = &dev->dev (here dev is the pci dev) So at this point, the cxl adapter's device's parent is the PCI device that I want to be refcounted properly. c) init calls cxl_register_adapter *) cxl_register_adapter calls device_register(&adapter->dev) So now we're in device_register, where dev is the adapter device, and we want to know if the PCI device is safe after we return. device_register(&adapter->dev) calls device_initialize() and then device_add(). device_add() does a get_device(). device_add() also explicitly grabs the device's parent, and calls get_device() on it: parent = get_device(dev->parent); So therefore, device_register() takes a lock on the parent PCI dev, which is what pci_dev_get() was guarding. pci_dev_get() can therefore be safely removed. Fixes: f204e0b8cedd ("cxl: Driver code for powernv PCIe based cards for userspace access") Cc: stable@vger.kernel.org Signed-off-by: Daniel Axtens <dja@axtens.net> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Set up and enable PSL TimebasePhilippe Bergheaud2015-08-30
| | | | | | | | | This patch configures the PSL Timebase function and enables it, after the CAPP has been initialized by OPAL. Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Remove racy attempt to force EEH invocation in resetDaniel Axtens2015-08-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cxl_reset currently PERSTs the slot, and then repeatedly tries to read MMIO space in order to kick off EEH. There are 2 problems with this: it's unnecessary, and it's racy. It's unnecessary because the PERST will bring down the PHB link. That will be picked up by the CAPP, which will send out an HMI. Skiboot, noticing an HMI from the CAPP, will send an OPAL notification to the kernel, which will trigger EEH recovery. It's also racy: the EEH recovery triggered by the CAPP will eventually cause the MMIO space to have its mapping invalidated and the pointer NULLed out. This races with our attempt to read the MMIO space. This is causing OOPSes in testing. Simply drop all the attempts to force EEH detection, and trust that Skiboot will send the notification and that we'll act on it. The Skiboot code to send the EEH notification has been in Skiboot for as long as CAPP recovery has been supported, so we don't need to worry about breaking obscure setups with ancient firmware. Cc: Ryan Grimm <grimm@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Fixes: 62fa19d4b4fd ("cxl: Add ability to reset the card") Signed-off-by: Daniel Axtens <dja@axtens.net> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Remove use of macro DEFINE_PCI_DEVICE_TABLEVaishali Thakkar2015-08-22
| | | | | | | | | | | | | | | | | | | | | | | Macro DEFINE_PCI_DEVICE_TABLE is deprecated. So, here use struct pci_device_id instead of DEFINE_PCI_DEVICE_TABLE with the goal of getting rid of this macro completely. The Coccinelle semantic patch that performs this transformation is as follows: @@ identifier a; declarer name DEFINE_PCI_DEVICE_TABLE; initializer i; @@ - DEFINE_PCI_DEVICE_TABLE(a) + const struct pci_device_id a[] = i; Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com> Acked-by: Michael Neuling <mikey@neuling.org> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: EEH supportDaniel Axtens2015-08-14
| | | | | | | | | EEH (Enhanced Error Handling) allows a driver to recover from the temporary failure of an attached PCI card. Enable basic CXL support for EEH. Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Allow the kernel to trust that an image won't change on PERST.Daniel Axtens2015-08-14
| | | | | | | | | | | | | Provide a kernel API and a sysfs entry which allow a user to specify that when a card is PERSTed, it's image will stay the same, allowing it to participate in EEH. cxl_reset is used to reflash the card. In that case, we cannot safely assert that the image will not change. Therefore, disallow cxl_reset if the flag is set. Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Don't remove AFUs/vPHBs in cxl_resetDaniel Axtens2015-08-14
| | | | | | | | | | | | | | If the driver doesn't participate in EEH, the AFUs will be removed by cxl_remove, which will be invoked by EEH. If the driver does particpate in EEH, the vPHB needs to stick around so that the it can particpate. In both cases, we shouldn't remove the AFU/vPHB. Reviewed-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Refactor AFU init/teardownDaniel Axtens2015-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | As with an adapter, some aspects of initialisation are done only once in the lifetime of an AFU: for example, allocating memory, or setting up sysfs/debugfs files. However, we may want to be able to do some parts of the initialisation multiple times: for example, in error recovery we want to be able to tear down and then re-map IO memory and IRQs. Therefore, refactor AFU init/teardown as follows. - Create two new functions: 'cxl_configure_afu', and its pair 'cxl_deconfigure_afu'. As with the adapter functions, these (de)configure resources that do not need to last the entire lifetime of the AFU. - Allocating and releasing memory remain the task of 'cxl_alloc_afu' and 'cxl_release_afu'. - Once-only functions that do not involve allocating/releasing memory stay in the overarching 'cxl_init_afu'/'cxl_remove_afu' pair. However, the task of picking an AFU mode and activating it has been broken out. Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Refactor adaptor init/teardownDaniel Axtens2015-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Some aspects of initialisation are done only once in the lifetime of an adapter: for example, allocating memory for the adapter, allocating the adapter number, or setting up sysfs/debugfs files. However, we may want to be able to do some parts of the initialisation multiple times: for example, in error recovery we want to be able to tear down and then re-map IO memory and IRQs. Therefore, refactor CXL init/teardown as follows. - Keep the overarching functions 'cxl_init_adapter' and its pair, 'cxl_remove_adapter'. - Move all 'once only' allocation/freeing steps to the existing 'cxl_alloc_adapter' function, and its pair 'cxl_release_adapter' (This involves moving allocation of the adapter number out of cxl_init_adapter.) - Create two new functions: 'cxl_configure_adapter', and its pair 'cxl_deconfigure_adapter'. These two functions 'wire up' the hardware --- they (de)configure resources that do not need to last the entire lifetime of the adapter Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Clean up adapter MMIO unmap path.Daniel Axtens2015-08-14
| | | | | | | | | | | | | | | - MMIO pointer unmapping is guarded by a null pointer check. However, iounmap doesn't null the pointer, just invalidate it. Therefore, explicitly null the pointer after unmapping. - afu_desc_mmio also needs to be unmapped. - PCI regions are allocated in cxl_map_adapter_regs. Therefore they should be released in unmap, not elsewhere. Acked-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Allocate and release the SPA with the AFUDaniel Axtens2015-08-14
| | | | | | | | | | | | | | | | | | | | | | | Previously the SPA was allocated and freed upon entering and leaving AFU-directed mode. This causes some issues for error recovery - contexts hold a pointer inside the SPA, and they may persist after the AFU has been detached. We would ideally like to allocate the SPA when the AFU is allocated, and release it until the AFU is released. However, we don't know how big the SPA needs to be until we read the AFU descriptor. Therefore, restructure the code: - Allocate the SPA only once, on the first attach. - Release the SPA only when the entire AFU is being released (not detached). Guard the release with a NULL check, so we don't free if it was never allocated (e.g. dedicated mode) Acked-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Destroy afu->contexts_idr on release of an afuJohannes Thumshirn2015-07-16
| | | | | | | | | Destroy afu->contexts_idr on release of an afu, reclaiming the allocated memory. Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: use more common format specifierRasmus Villemoes2015-07-13
| | | | | | | | | | A precision of 16 (%.16llx) has the same effect as a field width of 16 along with passing the 0 flag (%016llx), but the latter is much more common in the kernel tree. Update cxl to use that. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Test the correct mmio space before unmappingDaniel Axtens2015-07-06
| | | | | | | | Before freeing p2n, test p2n, not p1n. Signed-off-by: Daniel Axtens <dja@axtens.net> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Fix typo in debug printMichael Neuling2015-06-19
| | | | | | | | | Fix typo in debug print. p1_base() should be p2_base(). No change other than to the debug output. Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Add AFU virtual PHB and kernel APIMichael Neuling2015-06-03
| | | | | | | | | | | | | | | | | | | | | | | | | This patch does two things. Firstly it presents the Accelerator Function Unit (AFUs) behind the POWER Service Layer (PSL) as PCI devices on a virtual PCI Host Bridge (vPHB). This in in addition to the PSL being a PCI device itself. As part of the Coherent Accelerator Interface Architecture (CAIA) AFUs can provide an AFU configuration. This AFU configuration recored is architected to be the same as a PCI config space. This patch sets discovers the AFU configuration records, provides AFU config space read/write functions to these configuration records. It then enumerates the PCI bus. It also hooks in PCI ops where appropriate. It also destroys the vPHB when the physical card is removed. Secondly, it add an in kernel API for AFU to use CXL. AFUs must present a driver that firstly binds as a PCI device. This PCI device can then be using to do CXL specific operations (that can't sit in the PCI ops) using this API. Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: cxl_afu_reset() -> __cxl_afu_reset()Michael Neuling2015-06-03
| | | | | | | | | Rename cxl_afu_reset() to __cxl_afu_reset() to we can reuse this function name in the API. Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Dump debug info on the AFU configuration recordMichael Neuling2015-06-03
| | | | | | | | | Now that we parse the AFU Configuration record, dump some info on it when in debug mode. Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Fix error path on probeMichael Neuling2015-06-03
| | | | | | | | | | | | | | When probing we call pci_enable_device() but don't call pci_disable_device() on fail. This causes refcounting issues in the PCI subsystem if a second driver tries to bind to the same device. This patch adds the pci_disable_device() to the probe error path. This error path is hit when this cxl driver tries to bind to AFUs (on the vPHB) rather than the physical device. Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Re-order card init to check the VSEC earlierIan Munsie2015-06-03
| | | | | | | | | | | | | | | | When we expose AFUs as virtual PCI devices, they may look like the physical CAPI PCI card. ie they may have the same vendor/device IDs. We want to avoid these AFUs binding to this driver and any init this driver may do. Re-order card init to check the VSEC earlier before assigning BARs or activating CXL. Also change the dev used in early prints as the adapter struct may not be inited at this earlier stage. 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>
* cxl: Remove unnecessarily verbose print in cxl_remove()Michael Neuling2015-06-03
| | | | | | Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Add shutdown hookMichael Neuling2015-06-03
| | | | | | Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Export AFU error buffer via sysfsVaibhav Jain2015-06-03
| | | | | | | | | | | Export the "AFU Error Buffer" via sysfs attribute (afu_err_buf). AFU error buffer is used by the AFU to report application specific errors. The contents of this buffer are AFU specific and are intended to be interpreted by the application interacting with the afu. Suggested-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Fail AFU initialisation if an invalid configuration record is foundIan Munsie2015-02-06
| | | | | | | | | | | | If an AFU claims to have a configuration record but doesn't actually contain a vendor and device ID, fail the AFU initialisation. Right now this is just a way of politely letting AFU developers know that they need to fix their config space, but later on we may expose the AFUs as actual PCI devices in their own right and don't want to inadvertendly expose an AFU with a bad config space. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Export optional AFU configuration record in sysfsIan Munsie2015-02-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | An AFU may optionally contain one or more PCIe like configuration records, which can be used to identify the AFU. This patch adds support for exposing the raw config space and the vendor, device and class code under sysfs. These will appear in a subdirectory of the AFU device corresponding with the configuration record number, e.g. cat /sys/class/cxl/afu0.0/cr0/vendor 0x1014 cat /sys/class/cxl/afu0.0/cr0/device 0x4350 cat /sys/class/cxl/afu0.0/cr0/class 0x120000 hexdump -C /sys/class/cxl/afu0.0/cr0/config 00000000 14 10 50 43 00 00 00 00 06 00 00 12 00 00 00 00 |..PC............| 00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 00000100 These files behave in much the same way as the equivalent files for PCI devices, with one exception being that the config file is currently read-only and restricted to the root user. It is not necessarily required to be this strict, but we currently do not have a compelling use-case to make it writable and/or world-readable, so I erred on the side of being restrictive. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Fix device_node reference countingRyan Grimm2015-02-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When unbinding and rebinding the driver on a system with a card in PHB0, this error condition is reached after a few attempts: ERROR: Bad of_node_put() on /pciex@3fffe40000000 CPU: 0 PID: 3040 Comm: bash Not tainted 3.18.0-rc3-12545-g3627ffe #152 Call Trace: [c000000721acb5c0] [c00000000086ef94] .dump_stack+0x84/0xb0 (unreliable) [c000000721acb640] [c00000000073a0a8] .of_node_release+0xd8/0xe0 [c000000721acb6d0] [c00000000044bc44] .kobject_release+0x74/0xe0 [c000000721acb760] [c0000000007394fc] .of_node_put+0x1c/0x30 [c000000721acb7d0] [c000000000545cd8] .cxl_probe+0x1a98/0x1d50 [c000000721acb900] [c0000000004845a0] .local_pci_probe+0x40/0xc0 [c000000721acb980] [c000000000484998] .pci_device_probe+0x128/0x170 [c000000721acba30] [c00000000052400c] .driver_probe_device+0xac/0x2a0 [c000000721acbad0] [c000000000522468] .bind_store+0x108/0x160 [c000000721acbb70] [c000000000521448] .drv_attr_store+0x38/0x60 [c000000721acbbe0] [c000000000293840] .sysfs_kf_write+0x60/0xa0 [c000000721acbc50] [c000000000292500] .kernfs_fop_write+0x140/0x1d0 [c000000721acbcf0] [c000000000208648] .vfs_write+0xd8/0x260 [c000000721acbd90] [c000000000208b18] .SyS_write+0x58/0x100 [c000000721acbe30] [c000000000009258] syscall_exit+0x0/0x98 We are missing a call to of_node_get(). pnv_pci_to_phb_node() should call of_node_get() otherwise np's reference count isn't incremented and it might go away. Rename pnv_pci_to_phb_node() to pnv_pci_get_phb_node() so it's clear it calls of_node_get(). Signed-off-by: Ryan Grimm <grimm@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Add ability to reset the cardRyan Grimm2015-01-22
| | | | | | | | | | | | | | | | | | Adds reset to sysfs which will PERST the card. If load_image_on_perst is set to "user" or "factory", the PERST will cause that image to be loaded. load_image_on_perst is set to "user" for production. "none" could be used for debugging. The PSL trace arrays are preserved which then can be read through debugfs. PERST also triggers CAPP recovery. An HMI comes in, which is handled by EEH. EEH unbinds the driver, calls into Sapphire to reinitialize the PHB, then rebinds the driver. Signed-off-by: Ryan Grimm <grimm@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Enable CAPP recoveryRyan Grimm2015-01-22
| | | | | | | | | | | | Turning snoops on is the last step in CAPP recovery. Sapphire is expected to have reinitialized the PHB and done the previous recovery steps. Add mode argument to opal call to do this. Driver can turn snoops off although it does not currently. Signed-off-by: Ryan Grimm <grimm@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Use image state defaults for reloading FPGARyan Grimm2015-01-22
| | | | | | | | | | | | | | | | Select defaults such that a PERST causes flash image reload. Select which image based on what the card is set up to load. CXL_VSEC_PERST_LOADS_IMAGE selects whether PERST assertion causes flash image load. CXL_VSEC_PERST_SELECT_USER selects which image is loaded on the next PERST. cxl_update_image_control writes these bits into the VSEC. Signed-off-by: Ryan Grimm <grimm@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Disable AFU debug flagIan Munsie2014-12-29
| | | | | | | | | | | | | | | | | | | | | | | Upon inspection of the implementation specific registers, it was discovered that the high bit of the implementation specific RXCTL register was enabled, which enables the DEADB00F debug feature. The debug feature causes MMIO reads to a disabled AFU to respond with 0xDEADB00F instead of all Fs. In general this should not be visible as the kernel will only allow MMIO access to enabled AFUs, but there may be some circumstances where an AFU may become disabled while it is use. One such case would be an AFU designed to only be used in the dedicated process mode and to disable itself after it has completed it's work (however even in that case the effects of this debug flag would be limited as the userspace application must have completed any required MMIO accesses before the AFU disables itself with or without the flag). This patch removes the debug flag and replaces the magic value programmed into this register with a preprocessor define so it is clearer what the rest of this initialisation does. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Change contexts_lock to a mutex to fix sleep while atomic bugIan Munsie2014-12-12
| | | | | | | | | | | | | | | | | | | | | | | We had a known sleep while atomic bug if a CXL device was forcefully unbound while it was in use. This could occur as a result of EEH, or manually induced with something like this while the device was in use: echo 0000:01:00.0 > /sys/bus/pci/drivers/cxl-pci/unbind The issue was that in this code path we iterated over each context and forcefully detached it with the contexts_lock spin lock held, however the detach also needed to take the spu_mutex, and call schedule. This patch changes the contexts_lock to a mutex so that we are not in atomic context while doing the detach, thereby avoiding the sleep while atomic. Also delete the related TODO comment, which suggested an alternate solution which turned out to not be workable. Cc: stable@vger.kernel.org Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* cxl: Driver code for powernv PCIe based cards for userspace accessIan Munsie2014-10-08
This is the core of the cxl driver. It adds support for using cxl cards in the powernv environment only (ie POWER8 bare metal). It allows access to cxl accelerators by userspace using the /dev/cxl/afuM.N char devices. The kernel driver has no knowledge of the function implemented by the accelerator. It provides services to userspace via the /dev/cxl/afuM.N devices. When a program opens this device and runs the start work IOCTL, the accelerator will have coherent access to that processes memory using the same virtual addresses. That process may mmap the device to access any MMIO space the accelerator provides. Also, reads on the device will allow interrupts to be received. These services are further documented in a later patch in Documentation/powerpc/cxl.txt. Documentation of the cxl hardware architecture and userspace API is provided in subsequent patches. 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>