spi: core: add spi_replace_transfers method (523baf5a) · Commits · 戴 / test

drivers/spi/spi.c

+132 −0

Original line number	Diff line number	Diff line
		@@ -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.
		*/

include/linux/spi/spi.h

+45 −0

Original line number	Diff line number	Diff line
		@@ -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.

Admin message