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Diffstat (limited to 'arch/tile/include/hv/drv_xgbe_impl.h')
| -rw-r--r-- | arch/tile/include/hv/drv_xgbe_impl.h | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/arch/tile/include/hv/drv_xgbe_impl.h b/arch/tile/include/hv/drv_xgbe_impl.h new file mode 100644 index 0000000..3a73b2b --- /dev/null +++ b/arch/tile/include/hv/drv_xgbe_impl.h @@ -0,0 +1,300 @@ +/* + * Copyright 2010 Tilera Corporation. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + */ + +/** + * @file drivers/xgbe/impl.h + * Implementation details for the NetIO library. + */ + +#ifndef __DRV_XGBE_IMPL_H__ +#define __DRV_XGBE_IMPL_H__ + +#include <hv/netio_errors.h> +#include <hv/netio_intf.h> +#include <hv/drv_xgbe_intf.h> + + +/** How many groups we have (log2). */ +#define LOG2_NUM_GROUPS (12) +/** How many groups we have. */ +#define NUM_GROUPS (1 << LOG2_NUM_GROUPS) + +/** Number of output requests we'll buffer per tile. */ +#define EPP_REQS_PER_TILE (32) + +/** Words used in an eDMA command without checksum acceleration. */ +#define EDMA_WDS_NO_CSUM 8 +/** Words used in an eDMA command with checksum acceleration. */ +#define EDMA_WDS_CSUM 10 +/** Total available words in the eDMA command FIFO. */ +#define EDMA_WDS_TOTAL 128 + + +/* + * FIXME: These definitions are internal and should have underscores! + * NOTE: The actual numeric values here are intentional and allow us to + * optimize the concept "if small ... else if large ... else ...", by + * checking for the low bit being set, and then for non-zero. + * These are used as array indices, so they must have the values (0, 1, 2) + * in some order. + */ +#define SIZE_SMALL (1) /**< Small packet queue. */ +#define SIZE_LARGE (2) /**< Large packet queue. */ +#define SIZE_JUMBO (0) /**< Jumbo packet queue. */ + +/** The number of "SIZE_xxx" values. */ +#define NETIO_NUM_SIZES 3 + + +/* + * Default numbers of packets for IPP drivers. These values are chosen + * such that CIPP1 will not overflow its L2 cache. + */ + +/** The default number of small packets. */ +#define NETIO_DEFAULT_SMALL_PACKETS 2750 +/** The default number of large packets. */ +#define NETIO_DEFAULT_LARGE_PACKETS 2500 +/** The default number of jumbo packets. */ +#define NETIO_DEFAULT_JUMBO_PACKETS 250 + + +/** Log2 of the size of a memory arena. */ +#define NETIO_ARENA_SHIFT 24 /* 16 MB */ +/** Size of a memory arena. */ +#define NETIO_ARENA_SIZE (1 << NETIO_ARENA_SHIFT) + + +/** A queue of packets. + * + * This structure partially defines a queue of packets waiting to be + * processed. The queue as a whole is written to by an interrupt handler and + * read by non-interrupt code; this data structure is what's touched by the + * interrupt handler. The other part of the queue state, the read offset, is + * kept in user space, not in hypervisor space, so it is in a separate data + * structure. + * + * The read offset (__packet_receive_read in the user part of the queue + * structure) points to the next packet to be read. When the read offset is + * equal to the write offset, the queue is empty; therefore the queue must + * contain one more slot than the required maximum queue size. + * + * Here's an example of all 3 state variables and what they mean. All + * pointers move left to right. + * + * @code + * I I V V V V I I I I + * 0 1 2 3 4 5 6 7 8 9 10 + * ^ ^ ^ ^ + * | | | + * | | __last_packet_plus_one + * | __buffer_write + * __packet_receive_read + * @endcode + * + * This queue has 10 slots, and thus can hold 9 packets (_last_packet_plus_one + * = 10). The read pointer is at 2, and the write pointer is at 6; thus, + * there are valid, unread packets in slots 2, 3, 4, and 5. The remaining + * slots are invalid (do not contain a packet). + */ +typedef struct { + /** Byte offset of the next notify packet to be written: zero for the first + * packet on the queue, sizeof (netio_pkt_t) for the second packet on the + * queue, etc. */ + volatile uint32_t __packet_write; + + /** Offset of the packet after the last valid packet (i.e., when any + * pointer is incremented to this value, it wraps back to zero). */ + uint32_t __last_packet_plus_one; +} +__netio_packet_queue_t; + + +/** A queue of buffers. + * + * This structure partially defines a queue of empty buffers which have been + * obtained via requests to the IPP. (The elements of the queue are packet + * handles, which are transformed into a full netio_pkt_t when the buffer is + * retrieved.) The queue as a whole is written to by an interrupt handler and + * read by non-interrupt code; this data structure is what's touched by the + * interrupt handler. The other parts of the queue state, the read offset and + * requested write offset, are kept in user space, not in hypervisor space, so + * they are in a separate data structure. + * + * The read offset (__buffer_read in the user part of the queue structure) + * points to the next buffer to be read. When the read offset is equal to the + * write offset, the queue is empty; therefore the queue must contain one more + * slot than the required maximum queue size. + * + * The requested write offset (__buffer_requested_write in the user part of + * the queue structure) points to the slot which will hold the next buffer we + * request from the IPP, once we get around to sending such a request. When + * the requested write offset is equal to the write offset, no requests for + * new buffers are outstanding; when the requested write offset is one greater + * than the read offset, no more requests may be sent. + * + * Note that, unlike the packet_queue, the buffer_queue places incoming + * buffers at decreasing addresses. This makes the check for "is it time to + * wrap the buffer pointer" cheaper in the assembly code which receives new + * buffers, and means that the value which defines the queue size, + * __last_buffer, is different than in the packet queue. Also, the offset + * used in the packet_queue is already scaled by the size of a packet; here we + * use unscaled slot indices for the offsets. (These differences are + * historical, and in the future it's possible that the packet_queue will look + * more like this queue.) + * + * @code + * Here's an example of all 4 state variables and what they mean. Remember: + * all pointers move right to left. + * + * V V V I I R R V V V + * 0 1 2 3 4 5 6 7 8 9 + * ^ ^ ^ ^ + * | | | | + * | | | __last_buffer + * | | __buffer_write + * | __buffer_requested_write + * __buffer_read + * @endcode + * + * This queue has 10 slots, and thus can hold 9 buffers (_last_buffer = 9). + * The read pointer is at 2, and the write pointer is at 6; thus, there are + * valid, unread buffers in slots 2, 1, 0, 9, 8, and 7. The requested write + * pointer is at 4; thus, requests have been made to the IPP for buffers which + * will be placed in slots 6 and 5 when they arrive. Finally, the remaining + * slots are invalid (do not contain a buffer). + */ +typedef struct +{ + /** Ordinal number of the next buffer to be written: 0 for the first slot in + * the queue, 1 for the second slot in the queue, etc. */ + volatile uint32_t __buffer_write; + + /** Ordinal number of the last buffer (i.e., when any pointer is decremented + * below zero, it is reloaded with this value). */ + uint32_t __last_buffer; +} +__netio_buffer_queue_t; + + +/** + * An object for providing Ethernet packets to a process. + */ +typedef struct __netio_queue_impl_t +{ + /** The queue of packets waiting to be received. */ + __netio_packet_queue_t __packet_receive_queue; + /** The intr bit mask that IDs this device. */ + unsigned int __intr_id; + /** Offset to queues of empty buffers, one per size. */ + uint32_t __buffer_queue[NETIO_NUM_SIZES]; + /** The address of the first EPP tile, or -1 if no EPP. */ + /* ISSUE: Actually this is always "0" or "~0". */ + uint32_t __epp_location; + /** The queue ID that this queue represents. */ + unsigned int __queue_id; + /** Number of acknowledgements received. */ + volatile uint32_t __acks_received; + /** Last completion number received for packet_sendv. */ + volatile uint32_t __last_completion_rcv; + /** Number of packets allowed to be outstanding. */ + uint32_t __max_outstanding; + /** First VA available for packets. */ + void* __va_0; + /** First VA in second range available for packets. */ + void* __va_1; + /** Padding to align the "__packets" field to the size of a netio_pkt_t. */ + uint32_t __padding[3]; + /** The packets themselves. */ + netio_pkt_t __packets[0]; +} +netio_queue_impl_t; + + +/** + * An object for managing the user end of a NetIO queue. + */ +typedef struct __netio_queue_user_impl_t +{ + /** The next incoming packet to be read. */ + uint32_t __packet_receive_read; + /** The next empty buffers to be read, one index per size. */ + uint8_t __buffer_read[NETIO_NUM_SIZES]; + /** Where the empty buffer we next request from the IPP will go, one index + * per size. */ + uint8_t __buffer_requested_write[NETIO_NUM_SIZES]; + /** PCIe interface flag. */ + uint8_t __pcie; + /** Number of packets left to be received before we send a credit update. */ + uint32_t __receive_credit_remaining; + /** Value placed in __receive_credit_remaining when it reaches zero. */ + uint32_t __receive_credit_interval; + /** First fast I/O routine index. */ + uint32_t __fastio_index; + /** Number of acknowledgements expected. */ + uint32_t __acks_outstanding; + /** Last completion number requested. */ + uint32_t __last_completion_req; + /** File descriptor for driver. */ + int __fd; +} +netio_queue_user_impl_t; + + +#define NETIO_GROUP_CHUNK_SIZE 64 /**< Max # groups in one IPP request */ +#define NETIO_BUCKET_CHUNK_SIZE 64 /**< Max # buckets in one IPP request */ + + +/** Internal structure used to convey packet send information to the + * hypervisor. FIXME: Actually, it's not used for that anymore, but + * netio_packet_send() still uses it internally. + */ +typedef struct +{ + uint16_t flags; /**< Packet flags (__NETIO_SEND_FLG_xxx) */ + uint16_t transfer_size; /**< Size of packet */ + uint32_t va; /**< VA of start of packet */ + __netio_pkt_handle_t handle; /**< Packet handle */ + uint32_t csum0; /**< First checksum word */ + uint32_t csum1; /**< Second checksum word */ +} +__netio_send_cmd_t; + + +/** Flags used in two contexts: + * - As the "flags" member in the __netio_send_cmd_t, above; used only + * for netio_pkt_send_{prepare,commit}. + * - As part of the flags passed to the various send packet fast I/O calls. + */ + +/** Need acknowledgement on this packet. Note that some code in the + * normal send_pkt fast I/O handler assumes that this is equal to 1. */ +#define __NETIO_SEND_FLG_ACK 0x1 + +/** Do checksum on this packet. (Only used with the __netio_send_cmd_t; + * normal packet sends use a special fast I/O index to denote checksumming, + * and multi-segment sends test the checksum descriptor.) */ +#define __NETIO_SEND_FLG_CSUM 0x2 + +/** Get a completion on this packet. Only used with multi-segment sends. */ +#define __NETIO_SEND_FLG_COMPLETION 0x4 + +/** Position of the number-of-extra-segments value in the flags word. + Only used with multi-segment sends. */ +#define __NETIO_SEND_FLG_XSEG_SHIFT 3 + +/** Width of the number-of-extra-segments value in the flags word. */ +#define __NETIO_SEND_FLG_XSEG_WIDTH 2 + +#endif /* __DRV_XGBE_IMPL_H__ */ |