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spi: core: add spi_replace_transfers method
Add the spi_replace_transfers method that can get used to replace some spi_transfers from a spi_message with other transfers. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
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‎drivers/spi/spi.c

Lines changed: 132 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2107,6 +2107,138 @@ EXPORT_SYMBOL_GPL(spi_res_release);
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/*-------------------------------------------------------------------------*/
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/* Core methods for spi_message alterations */
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static void __spi_replace_transfers_release(struct spi_master *master,
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struct spi_message *msg,
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void *res)
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{
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struct spi_replaced_transfers *rxfer = res;
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size_t i;
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/* call extra callback if requested */
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if (rxfer->release)
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rxfer->release(master, msg, res);
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/* insert replaced transfers back into the message */
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list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
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/* remove the formerly inserted entries */
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for (i = 0; i < rxfer->inserted; i++)
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list_del(&rxfer->inserted_transfers[i].transfer_list);
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}
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/**
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* spi_replace_transfers - replace transfers with several transfers
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* and register change with spi_message.resources
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* @msg: the spi_message we work upon
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* @xfer_first: the first spi_transfer we want to replace
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* @remove: number of transfers to remove
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* @insert: the number of transfers we want to insert instead
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* @release: extra release code necessary in some circumstances
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* @extradatasize: extra data to allocate (with alignment guarantees
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* of struct @spi_transfer)
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*
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* Returns: pointer to @spi_replaced_transfers,
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* PTR_ERR(...) in case of errors.
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*/
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struct spi_replaced_transfers *spi_replace_transfers(
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struct spi_message *msg,
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struct spi_transfer *xfer_first,
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size_t remove,
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size_t insert,
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spi_replaced_release_t release,
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size_t extradatasize,
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gfp_t gfp)
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{
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struct spi_replaced_transfers *rxfer;
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struct spi_transfer *xfer;
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size_t i;
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/* allocate the structure using spi_res */
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rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
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insert * sizeof(struct spi_transfer)
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+ sizeof(struct spi_replaced_transfers)
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+ extradatasize,
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gfp);
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if (!rxfer)
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return ERR_PTR(-ENOMEM);
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/* the release code to invoke before running the generic release */
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rxfer->release = release;
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/* assign extradata */
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if (extradatasize)
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rxfer->extradata =
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&rxfer->inserted_transfers[insert];
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/* init the replaced_transfers list */
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INIT_LIST_HEAD(&rxfer->replaced_transfers);
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/* assign the list_entry after which we should reinsert
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* the @replaced_transfers - it may be spi_message.messages!
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*/
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rxfer->replaced_after = xfer_first->transfer_list.prev;
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/* remove the requested number of transfers */
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for (i = 0; i < remove; i++) {
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/* if the entry after replaced_after it is msg->transfers
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* then we have been requested to remove more transfers
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* than are in the list
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*/
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if (rxfer->replaced_after->next == &msg->transfers) {
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dev_err(&msg->spi->dev,
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"requested to remove more spi_transfers than are available\n");
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/* insert replaced transfers back into the message */
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list_splice(&rxfer->replaced_transfers,
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rxfer->replaced_after);
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/* free the spi_replace_transfer structure */
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spi_res_free(rxfer);
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/* and return with an error */
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return ERR_PTR(-EINVAL);
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}
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/* remove the entry after replaced_after from list of
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* transfers and add it to list of replaced_transfers
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*/
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list_move_tail(rxfer->replaced_after->next,
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&rxfer->replaced_transfers);
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}
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/* create copy of the given xfer with identical settings
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* based on the first transfer to get removed
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*/
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for (i = 0; i < insert; i++) {
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/* we need to run in reverse order */
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xfer = &rxfer->inserted_transfers[insert - 1 - i];
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/* copy all spi_transfer data */
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memcpy(xfer, xfer_first, sizeof(*xfer));
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/* add to list */
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list_add(&xfer->transfer_list, rxfer->replaced_after);
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/* clear cs_change and delay_usecs for all but the last */
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if (i) {
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xfer->cs_change = false;
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xfer->delay_usecs = 0;
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}
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}
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/* set up inserted */
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rxfer->inserted = insert;
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/* and register it with spi_res/spi_message */
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spi_res_add(msg, rxfer);
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return rxfer;
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}
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EXPORT_SYMBOL_GPL(spi_replace_transfers);
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/*-------------------------------------------------------------------------*/
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/* Core methods for SPI master protocol drivers. Some of the
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* other core methods are currently defined as inline functions.
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*/

‎include/linux/spi/spi.h

Lines changed: 45 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -890,6 +890,51 @@ spi_max_transfer_size(struct spi_device *spi)
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/*---------------------------------------------------------------------------*/
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/* SPI transfer replacement methods which make use of spi_res */
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/**
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* struct spi_replaced_transfers - structure describing the spi_transfer
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* replacements that have occurred
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* so that they can get reverted
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* @release: some extra release code to get executed prior to
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* relasing this structure
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* @extradata: pointer to some extra data if requested or NULL
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* @replaced_transfers: transfers that have been replaced and which need
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* to get restored
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* @replaced_after: the transfer after which the @replaced_transfers
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* are to get re-inserted
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* @inserted: number of transfers inserted
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* @inserted_transfers: array of spi_transfers of array-size @inserted,
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* that have been replacing replaced_transfers
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*
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* note: that @extradata will point to @inserted_transfers[@inserted]
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* if some extra allocation is requested, so alignment will be the same
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* as for spi_transfers
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*/
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struct spi_replaced_transfers;
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typedef void (*spi_replaced_release_t)(struct spi_master *master,
916+
struct spi_message *msg,
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struct spi_replaced_transfers *res);
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struct spi_replaced_transfers {
919+
spi_replaced_release_t release;
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void *extradata;
921+
struct list_head replaced_transfers;
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struct list_head *replaced_after;
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size_t inserted;
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struct spi_transfer inserted_transfers[];
925+
};
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extern struct spi_replaced_transfers *spi_replace_transfers(
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struct spi_message *msg,
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struct spi_transfer *xfer_first,
930+
size_t remove,
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size_t insert,
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spi_replaced_release_t release,
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size_t extradatasize,
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gfp_t gfp);
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936+
/*---------------------------------------------------------------------------*/
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893938
/* All these synchronous SPI transfer routines are utilities layered
894939
* over the core async transfer primitive. Here, "synchronous" means
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* they will sleep uninterruptibly until the async transfer completes.

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