diff options
| -rw-r--r-- | drivers/spi/spi.c | 132 | ||||
| -rw-r--r-- | include/linux/spi/spi.h | 45 |
2 files changed, 177 insertions, 0 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 894ed0357dd7..2ec8e66a8098 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2107,6 +2107,138 @@ EXPORT_SYMBOL_GPL(spi_res_release); /*-------------------------------------------------------------------------*/ +/* Core methods for spi_message alterations */ + +static void __spi_replace_transfers_release(struct spi_master *master, + struct spi_message *msg, + void *res) +{ + struct spi_replaced_transfers *rxfer = res; + size_t i; + + /* call extra callback if requested */ + if (rxfer->release) + rxfer->release(master, msg, res); + + /* insert replaced transfers back into the message */ + list_splice(&rxfer->replaced_transfers, rxfer->replaced_after); + + /* remove the formerly inserted entries */ + for (i = 0; i < rxfer->inserted; i++) + list_del(&rxfer->inserted_transfers[i].transfer_list); +} + +/** + * spi_replace_transfers - replace transfers with several transfers + * and register change with spi_message.resources + * @msg: the spi_message we work upon + * @xfer_first: the first spi_transfer we want to replace + * @remove: number of transfers to remove + * @insert: the number of transfers we want to insert instead + * @release: extra release code necessary in some circumstances + * @extradatasize: extra data to allocate (with alignment guarantees + * of struct @spi_transfer) + * + * Returns: pointer to @spi_replaced_transfers, + * PTR_ERR(...) in case of errors. + */ +struct spi_replaced_transfers *spi_replace_transfers( + struct spi_message *msg, + struct spi_transfer *xfer_first, + size_t remove, + size_t insert, + spi_replaced_release_t release, + size_t extradatasize, + gfp_t gfp) +{ + struct spi_replaced_transfers *rxfer; + struct spi_transfer *xfer; + size_t i; + + /* allocate the structure using spi_res */ + rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release, + insert * sizeof(struct spi_transfer) + + sizeof(struct spi_replaced_transfers) + + extradatasize, + gfp); + if (!rxfer) + return ERR_PTR(-ENOMEM); + + /* the release code to invoke before running the generic release */ + rxfer->release = release; + + /* assign extradata */ + if (extradatasize) + rxfer->extradata = + &rxfer->inserted_transfers[insert]; + + /* init the replaced_transfers list */ + INIT_LIST_HEAD(&rxfer->replaced_transfers); + + /* assign the list_entry after which we should reinsert + * the @replaced_transfers - it may be spi_message.messages! + */ + rxfer->replaced_after = xfer_first->transfer_list.prev; + + /* remove the requested number of transfers */ + for (i = 0; i < remove; i++) { + /* if the entry after replaced_after it is msg->transfers + * then we have been requested to remove more transfers + * than are in the list + */ + if (rxfer->replaced_after->next == &msg->transfers) { + dev_err(&msg->spi->dev, + "requested to remove more spi_transfers than are available\n"); + /* insert replaced transfers back into the message */ + list_splice(&rxfer->replaced_transfers, + rxfer->replaced_after); + + /* free the spi_replace_transfer structure */ + spi_res_free(rxfer); + + /* and return with an error */ + return ERR_PTR(-EINVAL); + } + + /* remove the entry after replaced_after from list of + * transfers and add it to list of replaced_transfers + */ + list_move_tail(rxfer->replaced_after->next, + &rxfer->replaced_transfers); + } + + /* create copy of the given xfer with identical settings + * based on the first transfer to get removed + */ + for (i = 0; i < insert; i++) { + /* we need to run in reverse order */ + xfer = &rxfer->inserted_transfers[insert - 1 - i]; + + /* copy all spi_transfer data */ + memcpy(xfer, xfer_first, sizeof(*xfer)); + + /* add to list */ + list_add(&xfer->transfer_list, rxfer->replaced_after); + + /* clear cs_change and delay_usecs for all but the last */ + if (i) { + xfer->cs_change = false; + xfer->delay_usecs = 0; + } + } + + /* set up inserted */ + rxfer->inserted = insert; + + /* and register it with spi_res/spi_message */ + spi_res_add(msg, rxfer); + + return rxfer; +} +EXPORT_SYMBOL_GPL(spi_replace_transfers); + +/*-------------------------------------------------------------------------*/ + /* Core methods for SPI master protocol drivers. Some of the * other core methods are currently defined as inline functions. */ diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 38204b584dc5..d71385756fee 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -890,6 +890,51 @@ spi_max_transfer_size(struct spi_device *spi) /*---------------------------------------------------------------------------*/ +/* SPI transfer replacement methods which make use of spi_res */ + +/** + * struct spi_replaced_transfers - structure describing the spi_transfer + * replacements that have occurred + * so that they can get reverted + * @release: some extra release code to get executed prior to + * relasing this structure + * @extradata: pointer to some extra data if requested or NULL + * @replaced_transfers: transfers that have been replaced and which need + * to get restored + * @replaced_after: the transfer after which the @replaced_transfers + * are to get re-inserted + * @inserted: number of transfers inserted + * @inserted_transfers: array of spi_transfers of array-size @inserted, + * that have been replacing replaced_transfers + * + * note: that @extradata will point to @inserted_transfers[@inserted] + * if some extra allocation is requested, so alignment will be the same + * as for spi_transfers + */ +struct spi_replaced_transfers; +typedef void (*spi_replaced_release_t)(struct spi_master *master, + struct spi_message *msg, + struct spi_replaced_transfers *res); +struct spi_replaced_transfers { + spi_replaced_release_t release; + void *extradata; + struct list_head replaced_transfers; + struct list_head *replaced_after; + size_t inserted; + struct spi_transfer inserted_transfers[]; +}; + +extern struct spi_replaced_transfers *spi_replace_transfers( + struct spi_message *msg, + struct spi_transfer *xfer_first, + size_t remove, + size_t insert, + spi_replaced_release_t release, + size_t extradatasize, + gfp_t gfp); + +/*---------------------------------------------------------------------------*/ + /* All these synchronous SPI transfer routines are utilities layered * over the core async transfer primitive. Here, "synchronous" means * they will sleep uninterruptibly until the async transfer completes. |