| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [diff] [blame] | 1 | RapidIO subsystem mport driver for IDT Tsi721 PCI Express-to-SRIO bridge. |
| 2 | ========================================================================= |
| 3 | |
| 4 | I. Overview |
| 5 | |
| 6 | This driver implements all currently defined RapidIO mport callback functions. |
| 7 | It supports maintenance read and write operations, inbound and outbound RapidIO |
| 8 | doorbells, inbound maintenance port-writes and RapidIO messaging. |
| 9 | |
| 10 | To generate SRIO maintenance transactions this driver uses one of Tsi721 DMA |
| 11 | channels. This mechanism provides access to larger range of hop counts and |
| 12 | destination IDs without need for changes in outbound window translation. |
| 13 | |
| 14 | RapidIO messaging support uses dedicated messaging channels for each mailbox. |
| 15 | For inbound messages this driver uses destination ID matching to forward messages |
| 16 | into the corresponding message queue. Messaging callbacks are implemented to be |
| 17 | fully compatible with RIONET driver (Ethernet over RapidIO messaging services). |
| 18 | |
| 19 | 1. Module parameters: |
| 20 | - 'dbg_level' - This parameter allows to control amount of debug information |
| 21 | generated by this device driver. This parameter is formed by set of |
| 22 | This parameter can be changed bit masks that correspond to the specific |
| 23 | functional block. |
| 24 | For mask definitions see 'drivers/rapidio/devices/tsi721.h' |
| 25 | This parameter can be changed dynamically. |
| 26 | Use CONFIG_RAPIDIO_DEBUG=y to enable debug output at the top level. |
| 27 | |
| 28 | - 'dma_desc_per_channel' - This parameter defines number of hardware buffer |
| 29 | descriptors allocated for each registered Tsi721 DMA channel. |
| 30 | Its default value is 128. |
| 31 | |
| 32 | - 'dma_txqueue_sz' - DMA transactions queue size. Defines number of pending |
| 33 | transaction requests that can be accepted by each DMA channel. |
| 34 | Default value is 16. |
| 35 | |
| 36 | - 'dma_sel' - DMA channel selection mask. Bitmask that defines which hardware |
| 37 | DMA channels (0 ... 6) will be registered with DmaEngine core. |
| 38 | If bit is set to 1, the corresponding DMA channel will be registered. |
| 39 | DMA channels not selected by this mask will not be used by this device |
| 40 | driver. Default value is 0x7f (use all channels). |
| 41 | |
| 42 | - 'pcie_mrrs' - override value for PCIe Maximum Read Request Size (MRRS). |
| 43 | This parameter gives an ability to override MRRS value set during PCIe |
| 44 | configuration process. Tsi721 supports read request sizes up to 4096B. |
| 45 | Value for this parameter must be set as defined by PCIe specification: |
| 46 | 0 = 128B, 1 = 256B, 2 = 512B, 3 = 1024B, 4 = 2048B and 5 = 4096B. |
| 47 | Default value is '-1' (= keep platform setting). |
| 48 | |
| 49 | - 'mbox_sel' - RIO messaging MBOX selection mask. This is a bitmask that defines |
| 50 | messaging MBOXes are managed by this device driver. Mask bits 0 - 3 |
| 51 | correspond to MBOX0 - MBOX3. MBOX is under driver's control if the |
| 52 | corresponding bit is set to '1'. Default value is 0x0f (= all). |
| 53 | |
| 54 | II. Known problems |
| 55 | |
| 56 | None. |
| 57 | |
| 58 | III. DMA Engine Support |
| 59 | |
| 60 | Tsi721 mport driver supports DMA data transfers between local system memory and |
| 61 | remote RapidIO devices. This functionality is implemented according to SLAVE |
| 62 | mode API defined by common Linux kernel DMA Engine framework. |
| 63 | |
| 64 | Depending on system requirements RapidIO DMA operations can be included/excluded |
| 65 | by setting CONFIG_RAPIDIO_DMA_ENGINE option. Tsi721 miniport driver uses seven |
| 66 | out of eight available BDMA channels to support DMA data transfers. |
| 67 | One BDMA channel is reserved for generation of maintenance read/write requests. |
| 68 | |
| 69 | If Tsi721 mport driver have been built with RAPIDIO_DMA_ENGINE support included, |
| 70 | this driver will accept DMA-specific module parameter: |
| 71 | "dma_desc_per_channel" - defines number of hardware buffer descriptors used by |
| 72 | each BDMA channel of Tsi721 (by default - 128). |
| 73 | |
| 74 | IV. Version History |
| 75 | |
| 76 | 1.1.0 - DMA operations re-worked to support data scatter/gather lists larger |
| 77 | than hardware buffer descriptors ring. |
| 78 | 1.0.0 - Initial driver release. |
| 79 | |
| 80 | V. License |
| 81 | ----------------------------------------------- |
| 82 | |
| 83 | Copyright(c) 2011 Integrated Device Technology, Inc. All rights reserved. |
| 84 | |
| 85 | This program is free software; you can redistribute it and/or modify it |
| 86 | under the terms of the GNU General Public License as published by the Free |
| 87 | Software Foundation; either version 2 of the License, or (at your option) |
| 88 | any later version. |
| 89 | |
| 90 | This program is distributed in the hope that it will be useful, but WITHOUT |
| 91 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 92 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 93 | more details. |
| 94 | |
| 95 | You should have received a copy of the GNU General Public License along with |
| 96 | this program; if not, write to the Free Software Foundation, Inc., |
| 97 | 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |