drivers/usb/musb/musb_dma.h

   1 /*
   2  * MUSB OTG driver DMA controller abstraction
   3  *
   4  * Copyright 2005 Mentor Graphics Corporation
   5  * Copyright (C) 2005-2006 by Texas Instruments
   6  * Copyright (C) 2006-2007 Nokia Corporation
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * version 2 as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  20  * 02110-1301 USA
  21  *
  22  * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
  23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  25  * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  28  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  29  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  *
  33  */
  34
  35 #ifndef __MUSB_DMA_H__
  36 #define __MUSB_DMA_H__
  37
  38 struct musb_hw_ep;
  39
  40 /*
  41  * DMA Controller Abstraction
  42  *
  43  * DMA Controllers are abstracted to allow use of a variety of different
  44  * implementations of DMA, as allowed by the Inventra USB cores.  On the
  45  * host side, usbcore sets up the DMA mappings and flushes caches; on the
  46  * peripheral side, the gadget controller driver does.  Responsibilities
  47  * of a DMA controller driver include:
  48  *
  49  *  - Handling the details of moving multiple USB packets
  50  *    in cooperation with the Inventra USB core, including especially
  51  *    the correct RX side treatment of short packets and buffer-full
  52  *    states (both of which terminate transfers).
  53  *
  54  *  - Knowing the correlation between dma channels and the
  55  *    Inventra core's local endpoint resources and data direction.
  56  *
  57  *  - Maintaining a list of allocated/available channels.
  58  *
  59  *  - Updating channel status on interrupts,
  60  *    whether shared with the Inventra core or separate.
  61  */
  62
  63 #define DMA_ADDR_INVALID        (~(dma_addr_t)0)
  64
  65 #ifndef CONFIG_MUSB_PIO_ONLY
  66 #define is_dma_capable()        (1)
  67 #else
  68 #define is_dma_capable()        (0)
  69 #endif
  70
  71 #ifdef CONFIG_USB_TI_CPPI_DMA
  72 #define is_cppi_enabled()       1
  73 #else
  74 #define is_cppi_enabled()       0
  75 #endif
  76
  77 #ifdef CONFIG_USB_TUSB_OMAP_DMA
  78 #define tusb_dma_omap()                 1
  79 #else
  80 #define tusb_dma_omap()                 0
  81 #endif
  82
  83 /*
  84  * DMA channel status ... updated by the dma controller driver whenever that
  85  * status changes, and protected by the overall controller spinlock.
  86  */
  87 enum dma_channel_status {
  88         /* unallocated */
  89         MUSB_DMA_STATUS_UNKNOWN,
  90         /* allocated ... but not busy, no errors */
  91         MUSB_DMA_STATUS_FREE,
  92         /* busy ... transactions are active */
  93         MUSB_DMA_STATUS_BUSY,
  94         /* transaction(s) aborted due to ... dma or memory bus error */
  95         MUSB_DMA_STATUS_BUS_ABORT,
  96         /* transaction(s) aborted due to ... core error or USB fault */
  97         MUSB_DMA_STATUS_CORE_ABORT
  98 };
  99
 100 struct dma_controller;
 101
 102 /**
 103  * struct dma_channel - A DMA channel.
 104  * @private_data: channel-private data
 105  * @max_len: the maximum number of bytes the channel can move in one
 106  *      transaction (typically representing many USB maximum-sized packets)
 107  * @actual_len: how many bytes have been transferred
 108  * @status: current channel status (updated e.g. on interrupt)
 109  * @desired_mode: true if mode 1 is desired; false if mode 0 is desired
 110  *
 111  * channels are associated with an endpoint for the duration of at least
 112  * one usb transfer.
 113  */
 114 struct dma_channel {
 115         void                    *private_data;
 116         /* FIXME not void* private_data, but a dma_controller * */
 117         size_t                  max_len;
 118         size_t                  actual_len;
 119         enum dma_channel_status status;
 120         bool                    desired_mode;
 121 };
 122
 123 /*
 124  * dma_channel_status - return status of dma channel
 125  * @c: the channel
 126  *
 127  * Returns the software's view of the channel status.  If that status is BUSY
 128  * then it's possible that the hardware has completed (or aborted) a transfer,
 129  * so the driver needs to update that status.
 130  */
 131 static inline enum dma_channel_status
 132 dma_channel_status(struct dma_channel *c)
 133 {
 134         return (is_dma_capable() && c) ? c->status : MUSB_DMA_STATUS_UNKNOWN;
 135 }
 136
 137 /**
 138  * struct dma_controller - A DMA Controller.
 139  * @start: call this to start a DMA controller;
 140  *      return 0 on success, else negative errno
 141  * @stop: call this to stop a DMA controller
 142  *      return 0 on success, else negative errno
 143  * @channel_alloc: call this to allocate a DMA channel
 144  * @channel_release: call this to release a DMA channel
 145  * @channel_abort: call this to abort a pending DMA transaction,
 146  *      returning it to FREE (but allocated) state
 147  *
 148  * Controllers manage dma channels.
 149  */
 150 struct dma_controller {
 151         int                     (*start)(struct dma_controller *);
 152         int                     (*stop)(struct dma_controller *);
 153         struct dma_channel      *(*channel_alloc)(struct dma_controller *,
 154                                         struct musb_hw_ep *, u8 is_tx);
 155         void                    (*channel_release)(struct dma_channel *);
 156         int                     (*channel_program)(struct dma_channel *channel,
 157                                                         u16 maxpacket, u8 mode,
 158                                                         dma_addr_t dma_addr,
 159                                                         u32 length);
 160         int                     (*channel_abort)(struct dma_channel *);
 161 };
 162
 163 /* called after channel_program(), may indicate a fault */
 164 extern void musb_dma_completion(struct musb *musb, u8 epnum, u8 transmit);
 165
 166
 167 extern struct dma_controller *__init
 168 dma_controller_create(struct musb *, void __iomem *);
 169
 170 extern void dma_controller_destroy(struct dma_controller *);
 171
 172 #endif  /* __MUSB_DMA_H__ */