| Message ID | 1449501708-2228-3-git-send-email-kernel@martin.sperl.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Dec 7, 2015 at 5:21 PM, <kernel@martin.sperl.org> wrote: > From: Martin Sperl <kernel@martin.sperl.org> > > Add the spi_replace_transfers method that can get used > to replace some spi_transfers from a spi_message with other > transfers. Few more implementation comments. > > Signed-off-by: Martin Sperl <kernel@martin.sperl.org> > --- > drivers/spi/spi.c | 130 +++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/spi/spi.h | 44 ++++++++++++++++ > 2 files changed, 174 insertions(+) > > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > index fb39d23..97c77b3 100644 > --- a/drivers/spi/spi.c > +++ b/drivers/spi/spi.c > @@ -2087,6 +2087,136 @@ 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 *srt = res; srt sounds magic rxfer might be better? > + int i; unsigned int i; or size_t to be in align with inserted field. > + > + /* call extra callback if requested */ > + if (srt->release) > + srt->release(master, msg, res); > + > + /* insert replaced transfers back into the message */ > + list_splice(&srt->replaced_transfers, srt->replaced_after); > + > + /* remove the formerly inserted entries */ > + for (i = 0; i < srt->inserted; i++) > + list_del(&srt->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, > + * NULL 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) > +{ > + struct spi_replaced_transfers *srt; > + int i; Ditto. > + > + /* allocate the structure using spi_res */ > + srt = spi_res_alloc(msg->spi, __spi_replace_transfers_release, > + insert * sizeof(struct spi_transfer) > + + sizeof(struct spi_replaced_transfers) > + + extradatasize, > + 0); > + if (!srt) > + return NULL; ERR_PTR for this API seems better to have. > + > + /* the release code to invoke before running the generic release */ > + srt->release = release; > + > + /* assign extradata */ > + if (extradatasize) > + srt->extradata = &srt->inserted_transfers[srt->inserted]; > + > + /* init the replaced_transfers list */ > + INIT_LIST_HEAD(&srt->replaced_transfers); > + > + /* assign the list_entry after which we should reinsert > + * the @replaced_transfers - it may be spi_message.messages! > + */ > + srt->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 (srt->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(&srt->replaced_transfers, > + srt->replaced_after); > + > + /* free the spi_replace_transfer structure */ > + spi_res_free(srt); > + > + /* and return with an error */ > + return NULL; > + } > + > + /* remove the entry after replaced_after from list of > + * transfers and add it to list of replaced_transfers > + */ > + list_move_tail(srt->replaced_after->next, > + &srt->replaced_transfers); > + } > + > + /* create copy of the given xfer with identical settings > + * based on the first transfer to get removed > + * note that we run in reverse to keep the array order > + * match the order in transfer_list > + */ > + srt->inserted = insert; > + for (i = insert - 1; i >= 0 ; i--) { This is classical pattern for while (--insert >= 0) { } > + /* copy all spi_transfer data */ > + memcpy(&srt->inserted_transfers[i], xfer_first, > + sizeof(*xfer_first)); > + > + /* for all but the last inserted_transfer, > + * clear some settings > + */ > + if (i < insert - 1) { …and if (insert) { } > + srt->inserted_transfers[i].cs_change = 0; > + srt->inserted_transfers[i].delay_usecs = 0; > + } > + > + /* add after srt->replaced_after */ > + list_add(&srt->inserted_transfers[i].transfer_list, > + srt->replaced_after); > + } > + > + /* and register it with spi_res/spi_message */ > + spi_res_add(msg, srt); > + > + return srt; > +} > +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 7e74e0e..35b5f17 100644 > --- a/include/linux/spi/spi.h > +++ b/include/linux/spi/spi.h > @@ -875,6 +875,50 @@ extern int spi_async_locked(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); > + > +/*---------------------------------------------------------------------------*/ > + > /* 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. > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-spi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
> On 11.12.2015, at 15:37, Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > > On Mon, Dec 7, 2015 at 5:21 PM, <kernel@martin.sperl.org> wrote: >> +/* 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 *srt = res; > > srt sounds magic > rxfer might be better? srt = Spi_Replaced_Transfer - if you like rxfer better I can replace it. > >> + int i; > > unsigned int i; or size_t to be in align with inserted field. will do. >> + int i; > > Ditto. > >> + >> + /* allocate the structure using spi_res */ >> + srt = spi_res_alloc(msg->spi, __spi_replace_transfers_release, >> + insert * sizeof(struct spi_transfer) >> + + sizeof(struct spi_replaced_transfers) >> + + extradatasize, >> + 0); >> + if (!srt) >> + return NULL; > > ERR_PTR for this API seems better to have. Can do that. >> + srt->inserted = insert; >> + for (i = insert - 1; i >= 0 ; i--) { > > This is classical pattern for > > while (--insert >= 0) { > } did it slightly differently as size_t is always >= 0 - the main reason for using int here... Martin -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index fb39d23..97c77b3 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2087,6 +2087,136 @@ 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 *srt = res; + int i; + + /* call extra callback if requested */ + if (srt->release) + srt->release(master, msg, res); + + /* insert replaced transfers back into the message */ + list_splice(&srt->replaced_transfers, srt->replaced_after); + + /* remove the formerly inserted entries */ + for (i = 0; i < srt->inserted; i++) + list_del(&srt->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, + * NULL 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) +{ + struct spi_replaced_transfers *srt; + int i; + + /* allocate the structure using spi_res */ + srt = spi_res_alloc(msg->spi, __spi_replace_transfers_release, + insert * sizeof(struct spi_transfer) + + sizeof(struct spi_replaced_transfers) + + extradatasize, + 0); + if (!srt) + return NULL; + + /* the release code to invoke before running the generic release */ + srt->release = release; + + /* assign extradata */ + if (extradatasize) + srt->extradata = &srt->inserted_transfers[srt->inserted]; + + /* init the replaced_transfers list */ + INIT_LIST_HEAD(&srt->replaced_transfers); + + /* assign the list_entry after which we should reinsert + * the @replaced_transfers - it may be spi_message.messages! + */ + srt->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 (srt->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(&srt->replaced_transfers, + srt->replaced_after); + + /* free the spi_replace_transfer structure */ + spi_res_free(srt); + + /* and return with an error */ + return NULL; + } + + /* remove the entry after replaced_after from list of + * transfers and add it to list of replaced_transfers + */ + list_move_tail(srt->replaced_after->next, + &srt->replaced_transfers); + } + + /* create copy of the given xfer with identical settings + * based on the first transfer to get removed + * note that we run in reverse to keep the array order + * match the order in transfer_list + */ + srt->inserted = insert; + for (i = insert - 1; i >= 0 ; i--) { + /* copy all spi_transfer data */ + memcpy(&srt->inserted_transfers[i], xfer_first, + sizeof(*xfer_first)); + + /* for all but the last inserted_transfer, + * clear some settings + */ + if (i < insert - 1) { + srt->inserted_transfers[i].cs_change = 0; + srt->inserted_transfers[i].delay_usecs = 0; + } + + /* add after srt->replaced_after */ + list_add(&srt->inserted_transfers[i].transfer_list, + srt->replaced_after); + } + + /* and register it with spi_res/spi_message */ + spi_res_add(msg, srt); + + return srt; +} +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 7e74e0e..35b5f17 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -875,6 +875,50 @@ extern int spi_async_locked(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); + +/*---------------------------------------------------------------------------*/ + /* 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.