diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-cxl | 129 | ||||
| -rw-r--r-- | Documentation/ioctl/ioctl-number.txt | 1 | ||||
| -rw-r--r-- | Documentation/powerpc/00-INDEX | 2 | ||||
| -rw-r--r-- | Documentation/powerpc/cxl.txt | 379 | ||||
| -rw-r--r-- | MAINTAINERS | 12 | ||||
| -rw-r--r-- | include/uapi/misc/cxl.h | 7 |
6 files changed, 527 insertions, 3 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-cxl b/Documentation/ABI/testing/sysfs-class-cxl new file mode 100644 index 00000000000..554405ec195 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-cxl @@ -0,0 +1,129 @@ +Slave contexts (eg. /sys/class/cxl/afu0.0s): + +What: /sys/class/cxl/<afu>/irqs_max +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read/write + Decimal value of maximum number of interrupts that can be + requested by userspace. The default on probe is the maximum + that hardware can support (eg. 2037). Write values will limit + userspace applications to that many userspace interrupts. Must + be >= irqs_min. + +What: /sys/class/cxl/<afu>/irqs_min +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Decimal value of the minimum number of interrupts that + userspace must request on a CXL_START_WORK ioctl. Userspace may + omit the num_interrupts field in the START_WORK IOCTL to get + this minimum automatically. + +What: /sys/class/cxl/<afu>/mmio_size +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Decimal value of the size of the MMIO space that may be mmaped + by userspace. + +What: /sys/class/cxl/<afu>/modes_supported +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + List of the modes this AFU supports. One per line. + Valid entries are: "dedicated_process" and "afu_directed" + +What: /sys/class/cxl/<afu>/mode +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read/write + The current mode the AFU is using. Will be one of the modes + given in modes_supported. Writing will change the mode + provided that no user contexts are attached. + + +What: /sys/class/cxl/<afu>/prefault_mode +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read/write + Set the mode for prefaulting in segments into the segment table + when performing the START_WORK ioctl. Possible values: + none: No prefaulting (default) + work_element_descriptor: Treat the work element + descriptor as an effective address and + prefault what it points to. + all: all segments process calling START_WORK maps. + +What: /sys/class/cxl/<afu>/reset +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: write only + Writing 1 here will reset the AFU provided there are not + contexts active on the AFU. + +What: /sys/class/cxl/<afu>/api_version +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Decimal value of the current version of the kernel/user API. + +What: /sys/class/cxl/<afu>/api_version_com +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Decimal value of the the lowest version of the userspace API + this this kernel supports. + + + +Master contexts (eg. /sys/class/cxl/afu0.0m) + +What: /sys/class/cxl/<afu>m/mmio_size +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Decimal value of the size of the MMIO space that may be mmaped + by userspace. This includes all slave contexts space also. + +What: /sys/class/cxl/<afu>m/pp_mmio_len +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Decimal value of the Per Process MMIO space length. + +What: /sys/class/cxl/<afu>m/pp_mmio_off +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Decimal value of the Per Process MMIO space offset. + + +Card info (eg. /sys/class/cxl/card0) + +What: /sys/class/cxl/<card>/caia_version +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Identifies the CAIA Version the card implements. + +What: /sys/class/cxl/<card>/psl_version +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Identifies the revision level of the PSL. + +What: /sys/class/cxl/<card>/base_image +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Identifies the revision level of the base image for devices + that support loadable PSLs. For FPGAs this field identifies + the image contained in the on-adapter flash which is loaded + during the initial program load. + +What: /sys/class/cxl/<card>/image_loaded +Date: September 2014 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Will return "user" or "factory" depending on the image loaded + onto the card. diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index 7e240a7c9ab..8136e1fd30f 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -313,6 +313,7 @@ Code Seq#(hex) Include File Comments 0xB1 00-1F PPPoX <mailto:mostrows@styx.uwaterloo.ca> 0xB3 00 linux/mmc/ioctl.h 0xC0 00-0F linux/usb/iowarrior.h +0xCA 00-0F uapi/misc/cxl.h 0xCB 00-1F CBM serial IEC bus in development: <mailto:michael.klein@puffin.lb.shuttle.de> 0xCD 01 linux/reiserfs_fs.h diff --git a/Documentation/powerpc/00-INDEX b/Documentation/powerpc/00-INDEX index a68784d0a1e..6fd0e8bb814 100644 --- a/Documentation/powerpc/00-INDEX +++ b/Documentation/powerpc/00-INDEX @@ -11,6 +11,8 @@ bootwrapper.txt cpu_features.txt - info on how we support a variety of CPUs with minimal compile-time options. +cxl.txt + - Overview of the CXL driver. eeh-pci-error-recovery.txt - info on PCI Bus EEH Error Recovery firmware-assisted-dump.txt diff --git a/Documentation/powerpc/cxl.txt b/Documentation/powerpc/cxl.txt new file mode 100644 index 00000000000..2c71ecc519d --- /dev/null +++ b/Documentation/powerpc/cxl.txt @@ -0,0 +1,379 @@ +Coherent Accelerator Interface (CXL) +==================================== + +Introduction +============ + + The coherent accelerator interface is designed to allow the + coherent connection of accelerators (FPGAs and other devices) to a + POWER system. These devices need to adhere to the Coherent + Accelerator Interface Architecture (CAIA). + + IBM refers to this as the Coherent Accelerator Processor Interface + or CAPI. In the kernel it's referred to by the name CXL to avoid + confusion with the ISDN CAPI subsystem. + + Coherent in this context means that the accelerator and CPUs can + both access system memory directly and with the same effective + addresses. + + +Hardware overview +================= + + POWER8 FPGA + +----------+ +---------+ + | | | | + | CPU | | AFU | + | | | | + | | | | + | | | | + +----------+ +---------+ + | PHB | | | + | +------+ | PSL | + | | CAPP |<------>| | + +---+------+ PCIE +---------+ + + The POWER8 chip has a Coherently Attached Processor Proxy (CAPP) + unit which is part of the PCIe Host Bridge (PHB). This is managed + by Linux by calls into OPAL. Linux doesn't directly program the + CAPP. + + The FPGA (or coherently attached device) consists of two parts. + The POWER Service Layer (PSL) and the Accelerator Function Unit + (AFU). The AFU is used to implement specific functionality behind + the PSL. The PSL, among other things, provides memory address + translation services to allow each AFU direct access to userspace + memory. + + The AFU is the core part of the accelerator (eg. the compression, + crypto etc function). The kernel has no knowledge of the function + of the AFU. Only userspace interacts directly with the AFU. + + The PSL provides the translation and interrupt services that the + AFU needs. This is what the kernel interacts with. For example, if + the AFU needs to read a particular effective address, it sends + that address to the PSL, the PSL then translates it, fetches the + data from memory and returns it to the AFU. If the PSL has a + translation miss, it interrupts the kernel and the kernel services + the fault. The context to which this fault is serviced is based on + who owns that acceleration function. + + +AFU Modes +========= + + There are two programming modes supported by the AFU. Dedicated + and AFU directed. AFU may support one or both modes. + + When using dedicated mode only one MMU context is supported. In + this mode, only one userspace process can use the accelerator at + time. + + When using AFU directed mode, up to 16K simultaneous contexts can + be supported. This means up to 16K simultaneous userspace + applications may use the accelerator (although specific AFUs may + support fewer). In this mode, the AFU sends a 16 bit context ID + with each of its requests. This tells the PSL which context is + associated with each operation. If the PSL can't translate an + operation, the ID can also be accessed by the kernel so it can + determine the userspace context associated with an operation. + + +MMIO space +========== + + A portion of the accelerator MMIO space can be directly mapped + from the AFU to userspace. Either the whole space can be mapped or + just a per context portion. The hardware is self describing, hence + the kernel can determine the offset and size of the per context + portion. + + +Interrupts +========== + + AFUs may generate interrupts that are destined for userspace. These + are received by the kernel as hardware interrupts and passed onto + userspace by a read syscall documented below. + + Data storage faults and error interrupts are handled by the kernel + driver. + + +Work Element Descriptor (WED) +============================= + + The WED is a 64-bit parameter passed to the AFU when a context is + started. Its format is up to the AFU hence the kernel has no + knowledge of what it represents. Typically it will be the + effective address of a work queue or status block where the AFU + and userspace can share control and status information. + + + + +User API +======== + + For AFUs operating in AFU directed mode, two character device + files will be created. /dev/cxl/afu0.0m will correspond to a + master context and /dev/cxl/afu0.0s will correspond to a slave + context. Master contexts have access to the full MMIO space an + AFU provides. Slave contexts have access to only the per process + MMIO space an AFU provides. + + For AFUs operating in dedicated process mode, the driver will + only create a single character device per AFU called + /dev/cxl/afu0.0d. This will have access to the entire MMIO space + that the AFU provides (like master contexts in AFU directed). + + The types described below are defined in include/uapi/misc/cxl.h + + The following file operations are supported on both slave and + master devices. + + +open +---- + + Opens the device and allocates a file descriptor to be used with + the rest of the API. + + A dedicated mode AFU only has one context and only allows the + device to be opened once. + + An AFU directed mode AFU can have many contexts, the device can be + opened once for each context that is available. + + When all available contexts are allocated the open call will fail + and return -ENOSPC. + + Note: IRQs need to be allocated for each context, which may limit + the number of contexts that can be created, and therefore + how many times the device can be opened. The POWER8 CAPP + supports 2040 IRQs and 3 are used by the kernel, so 2037 are + left. If 1 IRQ is needed per context, then only 2037 + contexts can be allocated. If 4 IRQs are needed per context, + then only 2037/4 = 509 contexts can be allocated. + + +ioctl +----- + + CXL_IOCTL_START_WORK: + Starts the AFU context and associates it with the current + process. Once this ioctl is successfully executed, all memory + mapped into this process is accessible to this AFU context + using the same effective addresses. No additional calls are + required to map/unmap memory. The AFU memory context will be + updated as userspace allocates and frees memory. This ioctl + returns once the AFU context is started. + + Takes a pointer to a struct cxl_ioctl_start_work: + + struct cxl_ioctl_start_work { + __u64 flags; + __u64 work_element_descriptor; + __u64 amr; + __s16 num_interrupts; + __s16 reserved1; + __s32 reserved2; + __u64 reserved3; + __u64 reserved4; + __u64 reserved5; + __u64 reserved6; + }; + + flags: + Indicates which optional fields in the structure are + valid. + + work_element_descriptor: + The Work Element Descriptor (WED) is a 64-bit argument + defined by the AFU. Typically this is an effective + address pointing to an AFU specific structure + describing what work to perform. + + amr: + Authority Mask Register (AMR), same as the powerpc + AMR. This field is only used by the kernel when the + corresponding CXL_START_WORK_AMR value is specified in + flags. If not specified the kernel will use a default + value of 0. + + num_interrupts: + Number of userspace interrupts to request. This field + is only used by the kernel when the corresponding + CXL_START_WORK_NUM_IRQS value is specified in flags. + If not specified the minimum number required by the + AFU will be allocated. The min and max number can be + obtained from sysfs. + + reserved fields: + For ABI padding and future extensions + + CXL_IOCTL_GET_PROCESS_ELEMENT: + Get the current context id, also known as the process element. + The value is returned from the kernel as a __u32. + + +mmap +---- + + An AFU may have an MMIO space to facilitate communication with the + AFU. If it does, the MMIO space can be accessed via mmap. The size + and contents of this area are specific to the particular AFU. The + size can be discovered via sysfs. + + In AFU directed mode, master contexts are allowed to map all of + the MMIO space and slave contexts are allowed to only map the per + process MMIO space associated with the context. In dedicated + process mode the entire MMIO space can always be mapped. + + This mmap call must be done after the START_WORK ioctl. + + Care should be taken when accessing MMIO space. Only 32 and 64-bit + accesses are supported by POWER8. Also, the AFU will be designed + with a specific endianness, so all MMIO accesses should consider + endianness (recommend endian(3) variants like: le64toh(), + be64toh() etc). These endian issues equally apply to shared memory + queues the WED may describe. + + +read +---- + + Reads events from the AFU. Blocks if no events are pending + (unless O_NONBLOCK is supplied). Returns -EIO in the case of an + unrecoverable error or if the card is removed. + + read() will always return an integral number of events. + + The buffer passed to read() must be at least 4K bytes. + + The result of the read will be a buffer of one or more events, + each event is of type struct cxl_event, of varying size. + + struct cxl_event { + struct cxl_event_header header; + union { + struct cxl_event_afu_interrupt irq; + struct cxl_event_data_storage fault; + struct cxl_event_afu_error afu_error; + }; + }; + + The struct cxl_event_header is defined as: + + struct cxl_event_header { + __u16 type; + __u16 size; + __u16 process_element; + __u16 reserved1; + }; + + type: + This defines the type of event. The type determines how + the rest of the event is structured. These types are + described below and defined by enum cxl_event_type. + + size: + This is the size of the event in bytes including the + struct cxl_event_header. The start of the next event can + be found at this offset from the start of the current + event. + + process_element: + Context ID of the event. + + reserved field: + For future extensions and padding. + + If the event type is CXL_EVENT_AFU_INTERRUPT then the event + structure is defined as: + + struct cxl_event_afu_interrupt { + __u16 flags; + __u16 irq; /* Raised AFU interrupt number */ + __u32 reserved1; + }; + + flags: + These flags indicate which optional fields are present + in this struct. Currently all fields are mandatory. + + irq: + The IRQ number sent by the AFU. + + reserved field: + For future extensions and padding. + + If the event type is CXL_EVENT_DATA_STORAGE then the event + structure is defined as: + + struct cxl_event_data_storage { + __u16 flags; + __u16 reserved1; + __u32 reserved2; + __u64 addr; + __u64 dsisr; + __u64 reserved3; + }; + + flags: + These flags indicate which optional fields are present in + this struct. Currently all fields are mandatory. + + address: + The address that the AFU unsuccessfully attempted to + access. Valid accesses will be handled transparently by the + kernel but invalid accesses will generate this event. + + dsisr: + This field gives information on the type of fault. It is a + copy of the DSISR from the PSL hardware when the address + fault occurred. The form of the DSISR is as defined in the + CAIA. + + reserved fields: + For future extensions + + If the event type is CXL_EVENT_AFU_ERROR then the event structure + is defined as: + + struct cxl_event_afu_error { + __u16 flags; + __u16 reserved1; + __u32 reserved2; + __u64 error; + }; + + flags: + These flags indicate which optional fields are present in + this struct. Currently all fields are Mandatory. + + error: + Error status from the AFU. Defined by the AFU. + + reserved fields: + For future extensions and padding + +Sysfs Class +=========== + + A cxl sysfs class is added under /sys/class/cxl to facilitate + enumeration and tuning of the accelerators. Its layout is + described in Documentation/ABI/testing/sysfs-class-cxl + +Udev rules +========== + + The following udev rules could be used to create a symlink to the + most logical chardev to use in any programming mode (afuX.Yd for + dedicated, afuX.Ys for afu directed), since the API is virtually + identical for each: + + SUBSYSTEM=="cxl", ATTRS{mode}=="dedicated_process", SYMLINK="cxl/%b" + SUBSYSTEM=="cxl", ATTRS{mode}=="afu_directed", \ + KERNEL=="afu[0-9]*.[0-9]*s", SYMLINK="cxl/%b" diff --git a/MAINTAINERS b/MAINTAINERS index 809ecd680d8..facc2198eab 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2711,6 +2711,18 @@ W: http://www.chelsio.com S: Supported F: drivers/net/ethernet/chelsio/cxgb4vf/ +CXL (IBM Coherent Accelerator Processor Interface CAPI) DRIVER +M: Ian Munsie <imunsie@au1.ibm.com> +M: Michael Neuling <mikey@neuling.org> +L: linuxppc-dev@lists.ozlabs.org +S: Supported +F: drivers/misc/cxl/ +F: include/misc/cxl.h +F: include/uapi/misc/cxl.h +F: Documentation/powerpc/cxl.txt +F: Documentation/powerpc/cxl.txt +F: Documentation/ABI/testing/sysfs-class-cxl + STMMAC ETHERNET DRIVER M: Giuseppe Cavallaro <peppe.cavallaro@st.com> L: netdev@vger.kernel.org diff --git a/include/uapi/misc/cxl.h b/include/uapi/misc/cxl.h index c232be6ae21..cd6d789b73e 100644 --- a/include/uapi/misc/cxl.h +++ b/include/uapi/misc/cxl.h @@ -13,7 +13,7 @@ #include <linux/types.h> #include <linux/ioctl.h> -/* Structs for IOCTLS for userspace to talk to the kernel */ + struct cxl_ioctl_start_work { __u64 flags; __u64 work_element_descriptor; @@ -26,19 +26,20 @@ struct cxl_ioctl_start_work { __u64 reserved5; __u64 reserved6; }; + #define CXL_START_WORK_AMR 0x0000000000000001ULL #define CXL_START_WORK_NUM_IRQS 0x0000000000000002ULL #define CXL_START_WORK_ALL (CXL_START_WORK_AMR |\ CXL_START_WORK_NUM_IRQS) -/* IOCTL numbers */ +/* ioctl numbers */ #define CXL_MAGIC 0xCA #define CXL_IOCTL_START_WORK _IOW(CXL_MAGIC, 0x00, struct cxl_ioctl_start_work) #define CXL_IOCTL_GET_PROCESS_ELEMENT _IOR(CXL_MAGIC, 0x01, __u32) -/* Events from read() */ #define CXL_READ_MIN_SIZE 0x1000 /* 4K */ +/* Events from read() */ enum cxl_event_type { CXL_EVENT_RESERVED = 0, CXL_EVENT_AFU_INTERRUPT = 1, |