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authorRobin Gong <yibin.gong@nxp.com>2020-06-17 06:42:08 +0800
committerMark Brown <broonie@kernel.org>2020-06-23 13:38:14 +0100
commit809b1b04df898b6d182069146231a3cbf5f2d9cc (patch)
tree64458c4970bab1cdccef890aa54f6267fa28c346 /include/linux/spi
parentc314360cea42e9481d9f68a73a3a776eba31ba4b (diff)
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 <yibin.gong@nxp.com> Link: https://lore.kernel.org/r/1592347329-28363-2-git-send-email-yibin.gong@nxp.com Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include/linux/spi')
-rw-r--r--include/linux/spi/spi.h7
1 files changed, 7 insertions, 0 deletions
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;
};
/**