From 809b1b04df898b6d182069146231a3cbf5f2d9cc Mon Sep 17 00:00:00 2001 From: Robin Gong Date: Wed, 17 Jun 2020 06:42:08 +0800 Subject: spi: introduce fallback to pio Add fallback to pio mode in case dma transfer failed with error status SPI_TRANS_FAIL_NO_START. If spi client driver want to enable this feature please set xfer->error in the proper place such as dmaengine_prep_slave_sg() failure detect(but no any data put into spi bus yet). Besides, add master->fallback checking in its can_dma() so that spi core could switch to pio next time. Please refer to spi-imx.c. Signed-off-by: Robin Gong Link: https://lore.kernel.org/r/1592347329-28363-2-git-send-email-yibin.gong@nxp.com Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index aac57b5b7c21..b4917df79637 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -447,6 +447,8 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * If the driver does not set this, the SPI core takes the snapshot as * close to the driver hand-over as possible. * @irq_flags: Interrupt enable state during PTP system timestamping + * @fallback: fallback to pio if dma transfer return failure with + * SPI_TRANS_FAIL_NO_START. * * Each SPI controller can communicate with one or more @spi_device * children. These make a small bus, sharing MOSI, MISO and SCK signals @@ -602,6 +604,7 @@ struct spi_controller { bool auto_runtime_pm; bool cur_msg_prepared; bool cur_msg_mapped; + bool fallback; struct completion xfer_completion; size_t max_dma_len; @@ -847,6 +850,7 @@ extern void spi_res_release(struct spi_controller *ctlr, * back unset and they need the better resolution. * @timestamped_post: See above. The reason why both exist is that these * booleans are also used to keep state in the core SPI logic. + * @error: Error status logged by spi controller driver. * * SPI transfers always write the same number of bytes as they read. * Protocol drivers should always provide @rx_buf and/or @tx_buf. @@ -940,6 +944,9 @@ struct spi_transfer { bool timestamped; struct list_head transfer_list; + +#define SPI_TRANS_FAIL_NO_START BIT(0) + u16 error; }; /** -- cgit From d40f0b6f2e21f2400ae8b1b120d11877d9ffd8ec Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Mon, 29 Jun 2020 16:41:06 -0700 Subject: spi: Avoid setting the chip select if we don't need to On some SPI controllers (like spi-geni-qcom) setting the chip select is a heavy operation. For instance on spi-geni-qcom, with the current code, is was measured as taking upwards of 20 us. Even on SPI controllers that aren't as heavy, setting the chip select is at least something like a MMIO operation over some peripheral bus which isn't as fast as a RAM access. While it would be good to find ways to mitigate problems like this in the drivers for those SPI controllers, it can also be noted that the SPI framework could also help out. Specifically, in some situations, we can see the SPI framework calling the driver's set_cs() with the same parameter several times in a row. This is specifically observed when looking at the way the Chrome OS EC SPI driver (cros_ec_spi) works but other drivers likely trip it to some extent. Let's solve this by caching the chip select state in the core and only calling into the controller if there was a change. We check not only the "enable" state but also the chip select mode (active high or active low) since controllers may care about both the mode and the enable flag in their callback. Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20200629164103.1.Ied8e8ad8bbb2df7f947e3bc5ea1c315e041785a2@changeid Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index b4917df79637..0e67a9a3a1d3 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -368,6 +368,8 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @cur_msg_prepared: spi_prepare_message was called for the currently * in-flight message * @cur_msg_mapped: message has been mapped for DMA + * @last_cs_enable: was enable true on the last call to set_cs. + * @last_cs_mode_high: was (mode & SPI_CS_HIGH) true on the last call to set_cs. * @xfer_completion: used by core transfer_one_message() * @busy: message pump is busy * @running: message pump is running @@ -604,6 +606,8 @@ struct spi_controller { bool auto_runtime_pm; bool cur_msg_prepared; bool cur_msg_mapped; + bool last_cs_enable; + bool last_cs_mode_high; bool fallback; struct completion xfer_completion; size_t max_dma_len; -- cgit From 60a883d119ab9ef63f830c85bbd2f0e2e2314f4f Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Thu, 9 Jul 2020 08:50:07 +0200 Subject: spi: use kthread_create_worker() helper Use kthread_create_worker() helper to simplify the code. It uses the kthread worker API the right way. It will eventually allow to remove the FIXME in kthread_worker_fn() and add more consistency checks in the future. Signed-off-by: Marek Szyprowski Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20200709065007.26896-1-m.szyprowski@samsung.com Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 0e67a9a3a1d3..5fcf5da13fdb 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -358,8 +358,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @cleanup: frees controller-specific state * @can_dma: determine whether this controller supports DMA * @queued: whether this controller is providing an internal message queue - * @kworker: thread struct for message pump - * @kworker_task: pointer to task for message pump kworker thread + * @kworker: pointer to thread struct for message pump * @pump_messages: work struct for scheduling work to the message pump * @queue_lock: spinlock to syncronise access to message queue * @queue: message queue @@ -593,8 +592,7 @@ struct spi_controller { * Over time we expect SPI drivers to be phased over to this API. */ bool queued; - struct kthread_worker kworker; - struct task_struct *kworker_task; + struct kthread_worker *kworker; struct kthread_work pump_messages; spinlock_t queue_lock; struct list_head queue; -- cgit From 2ae3de10abfe0be40c9d93ebc2f429b969abf008 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Wed, 15 Jul 2020 18:30:48 -0700 Subject: spi: fix duplicated word in Change doubled word "as" to "as a". Change "Return: Return:" in kernel-doc notation to have only one "Return:". Signed-off-by: Randy Dunlap Cc: Mark Brown Cc: linux-spi@vger.kernel.org Link: https://lore.kernel.org/r/40354d64-be71-3952-a980-63a76a278145@infradead.org Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 5fcf5da13fdb..f8b721fcd5c6 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -971,7 +971,7 @@ struct spi_transfer { * each represented by a struct spi_transfer. The sequence is "atomic" * in the sense that no other spi_message may use that SPI bus until that * sequence completes. On some systems, many such sequences can execute as - * as single programmed DMA transfer. On all systems, these messages are + * a single programmed DMA transfer. On all systems, these messages are * queued, and might complete after transactions to other devices. Messages * sent to a given spi_device are always executed in FIFO order. * @@ -1234,7 +1234,7 @@ extern int spi_bus_unlock(struct spi_controller *ctlr); * * For more specific semantics see spi_sync(). * - * Return: Return: zero on success, else a negative error code. + * Return: zero on success, else a negative error code. */ static inline int spi_sync_transfer(struct spi_device *spi, struct spi_transfer *xfers, -- cgit From cfd97f94d036bf36122fa19d075c5741347aa178 Mon Sep 17 00:00:00 2001 From: Colton Lewis Date: Sat, 25 Jul 2020 05:02:57 +0000 Subject: spi: correct kernel-doc inconsistency Silence documentation build warnings by correcting kernel-doc comment for spi_transfer struct. Signed-off-by: Colton Lewis Link: https://lore.kernel.org/r/20200725050242.279548-1-colton.w.lewis@protonmail.com Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index f8b721fcd5c6..99380c0825db 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -329,6 +329,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * every chipselect is connected to a slave. * @dma_alignment: SPI controller constraint on DMA buffers alignment. * @mode_bits: flags understood by this controller driver + * @buswidth_override_bits: flags to override for this controller driver * @bits_per_word_mask: A mask indicating which values of bits_per_word are * supported by the driver. Bit n indicates that a bits_per_word n+1 is * supported. If set, the SPI core will reject any transfer with an @@ -846,12 +847,7 @@ extern void spi_res_release(struct spi_controller *ctlr, * processed the word, i.e. the "pre" timestamp should be taken before * transmitting the "pre" word, and the "post" timestamp after receiving * transmit confirmation from the controller for the "post" word. - * @timestamped_pre: Set by the SPI controller driver to denote it has acted - * upon the @ptp_sts request. Not set when the SPI core has taken care of - * the task. SPI device drivers are free to print a warning if this comes - * back unset and they need the better resolution. - * @timestamped_post: See above. The reason why both exist is that these - * booleans are also used to keep state in the core SPI logic. + * @timestamped: true if the transfer has been timestamped * @error: Error status logged by spi controller driver. * * SPI transfers always write the same number of bytes as they read. -- cgit