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110 lines
5.1 KiB
110 lines
5.1 KiB
================================================================== |
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RapidIO subsystem mport character device driver (rio_mport_cdev.c) |
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================================================================== |
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1. Overview |
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=========== |
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This device driver is the result of collaboration within the RapidIO.org |
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Software Task Group (STG) between Texas Instruments, Freescale, |
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Prodrive Technologies, Nokia Networks, BAE and IDT. Additional input was |
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received from other members of RapidIO.org. The objective was to create a |
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character mode driver interface which exposes the capabilities of RapidIO |
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devices directly to applications, in a manner that allows the numerous and |
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varied RapidIO implementations to interoperate. |
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This driver (MPORT_CDEV) provides access to basic RapidIO subsystem operations |
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for user-space applications. Most of RapidIO operations are supported through |
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'ioctl' system calls. |
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When loaded this device driver creates filesystem nodes named rio_mportX in /dev |
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directory for each registered RapidIO mport device. 'X' in the node name matches |
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to unique port ID assigned to each local mport device. |
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Using available set of ioctl commands user-space applications can perform |
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following RapidIO bus and subsystem operations: |
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- Reads and writes from/to configuration registers of mport devices |
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(RIO_MPORT_MAINT_READ_LOCAL/RIO_MPORT_MAINT_WRITE_LOCAL) |
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- Reads and writes from/to configuration registers of remote RapidIO devices. |
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This operations are defined as RapidIO Maintenance reads/writes in RIO spec. |
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(RIO_MPORT_MAINT_READ_REMOTE/RIO_MPORT_MAINT_WRITE_REMOTE) |
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- Set RapidIO Destination ID for mport devices (RIO_MPORT_MAINT_HDID_SET) |
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- Set RapidIO Component Tag for mport devices (RIO_MPORT_MAINT_COMPTAG_SET) |
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- Query logical index of mport devices (RIO_MPORT_MAINT_PORT_IDX_GET) |
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- Query capabilities and RapidIO link configuration of mport devices |
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(RIO_MPORT_GET_PROPERTIES) |
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- Enable/Disable reporting of RapidIO doorbell events to user-space applications |
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(RIO_ENABLE_DOORBELL_RANGE/RIO_DISABLE_DOORBELL_RANGE) |
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- Enable/Disable reporting of RIO port-write events to user-space applications |
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(RIO_ENABLE_PORTWRITE_RANGE/RIO_DISABLE_PORTWRITE_RANGE) |
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- Query/Control type of events reported through this driver: doorbells, |
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port-writes or both (RIO_SET_EVENT_MASK/RIO_GET_EVENT_MASK) |
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- Configure/Map mport's outbound requests window(s) for specific size, |
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RapidIO destination ID, hopcount and request type |
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(RIO_MAP_OUTBOUND/RIO_UNMAP_OUTBOUND) |
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- Configure/Map mport's inbound requests window(s) for specific size, |
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RapidIO base address and local memory base address |
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(RIO_MAP_INBOUND/RIO_UNMAP_INBOUND) |
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- Allocate/Free contiguous DMA coherent memory buffer for DMA data transfers |
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to/from remote RapidIO devices (RIO_ALLOC_DMA/RIO_FREE_DMA) |
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- Initiate DMA data transfers to/from remote RapidIO devices (RIO_TRANSFER). |
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Supports blocking, asynchronous and posted (a.k.a 'fire-and-forget') data |
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transfer modes. |
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- Check/Wait for completion of asynchronous DMA data transfer |
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(RIO_WAIT_FOR_ASYNC) |
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- Manage device objects supported by RapidIO subsystem (RIO_DEV_ADD/RIO_DEV_DEL). |
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This allows implementation of various RapidIO fabric enumeration algorithms |
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as user-space applications while using remaining functionality provided by |
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kernel RapidIO subsystem. |
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2. Hardware Compatibility |
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========================= |
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This device driver uses standard interfaces defined by kernel RapidIO subsystem |
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and therefore it can be used with any mport device driver registered by RapidIO |
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subsystem with limitations set by available mport implementation. |
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At this moment the most common limitation is availability of RapidIO-specific |
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DMA engine framework for specific mport device. Users should verify available |
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functionality of their platform when planning to use this driver: |
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- IDT Tsi721 PCIe-to-RapidIO bridge device and its mport device driver are fully |
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compatible with this driver. |
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- Freescale SoCs 'fsl_rio' mport driver does not have implementation for RapidIO |
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specific DMA engine support and therefore DMA data transfers mport_cdev driver |
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are not available. |
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3. Module parameters |
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==================== |
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- 'dma_timeout' |
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- DMA transfer completion timeout (in msec, default value 3000). |
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This parameter set a maximum completion wait time for SYNC mode DMA |
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transfer requests and for RIO_WAIT_FOR_ASYNC ioctl requests. |
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- 'dbg_level' |
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- This parameter allows to control amount of debug information |
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generated by this device driver. This parameter is formed by set of |
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bit masks that correspond to the specific functional blocks. |
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For mask definitions see 'drivers/rapidio/devices/rio_mport_cdev.c' |
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This parameter can be changed dynamically. |
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Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level. |
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4. Known problems |
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================= |
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None. |
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5. User-space Applications and API |
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================================== |
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API library and applications that use this device driver are available from |
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RapidIO.org. |
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6. TODO List |
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============ |
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- Add support for sending/receiving "raw" RapidIO messaging packets. |
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- Add memory mapped DMA data transfers as an option when RapidIO-specific DMA |
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is not available.
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