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') 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 v1.2.3