From mboxrd@z Thu Jan 1 00:00:00 1970 From: kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org Subject: [PATCH v3 6/8] spi: core: add spi_master.translate_message Date: Mon, 14 Dec 2015 15:20:23 +0000 Message-ID: <1450106426-2277-7-git-send-email-kernel@martin.sperl.org> References: <1450106426-2277-1-git-send-email-kernel@martin.sperl.org> Cc: Martin Sperl To: Mark Brown , Stephen Warren , Lee Jones , Eric Anholt , linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Return-path: In-Reply-To: <1450106426-2277-1-git-send-email-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: From: Martin Sperl Add translate_message to spi_master structure to allow translations of spi_messages to happen independently of prepare messages. This "translations" are supposed to be using spi_res to handle the reverse transformation (see spi_replace_transfers), so no explicit code is necessary to revert any changes. dma_mapping of spi_messages could also become part of this processing. The long-term view is that this translation as well as the dma_mapping of the messages may happen in a separate thread when we are queueing those spi_messages - this would allows for better use of cpu resources as well as reduction of latency in the case of queuing. Signed-off-by: Martin Sperl --- drivers/spi/spi.c | 15 +++++++++++++++ include/linux/spi/spi.h | 4 ++++ 2 files changed, 19 insertions(+) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index fe3b18e..020e34d 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1170,6 +1170,21 @@ static void __spi_pump_messages(struct spi_master *master, bool in_kthread) trace_spi_message_start(master->cur_msg); + /* under some circumstances (i.e: when queuing a message) this + * could get moved to a separate thread to reduce latencies + * this could also handle the mapping of spi_transfers + */ + if (master->translate_message) { + ret = master->translate_message(master, master->cur_msg); + if (ret) { + dev_err(&master->dev, + "failed to translate message: %d\n", ret); + master->cur_msg->status = ret; + spi_finalize_current_message(master); + return; + } + } + if (master->prepare_message) { ret = master->prepare_message(master, master->cur_msg); if (ret) { diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 7172e73..4b4c1e9 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -379,6 +379,8 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @handle_err: the subsystem calls the driver to handle an error that occurs * in the generic implementation of transfer_one_message(). * @unprepare_message: undo any work done by prepare_message(). + * @translate_message: apply some message translations to optimize for the + * spi_master * @cs_gpios: Array of GPIOs to use as chip select lines; one per CS * number. Any individual value may be -ENOENT for CS lines that * are not GPIOs (driven by the SPI controller itself). @@ -525,6 +527,8 @@ struct spi_master { struct spi_message *message); int (*unprepare_message)(struct spi_master *master, struct spi_message *message); + int (*translate_message)(struct spi_master *master, + struct spi_message *message); /* * These hooks are for drivers that use a generic implementation -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html