From: Abhishek Sahu absahu@codeaurora.org
commit 7239872fb3400b21a8f5547257f9f86455867bd6 upstream.
The QUP BSLP BAM generates the following error sometimes if the current I2C DMA transfer fails and the flush operation has been scheduled
“bam-dma-engine 7884000.dma: Cannot free busy channel”
If any I2C error comes during BAM DMA transfer, then the QUP I2C interrupt will be generated and the flush operation will be carried out to make I2C consume all scheduled DMA transfer. Currently, the same completion structure is being used for BAM transfer which has already completed without reinit. It will make flush operation wait_for_completion_timeout completed immediately and will proceed for freeing the DMA resources where the descriptors are still in process.
Signed-off-by: Abhishek Sahu absahu@codeaurora.org Acked-by: Sricharan R sricharan@codeaurora.org Reviewed-by: Austin Christ austinwc@codeaurora.org Reviewed-by: Andy Gross andy.gross@linaro.org Signed-off-by: Wolfram Sang wsa@the-dreams.de Signed-off-by: Amit Pundir amit.pundir@linaro.org --- Cherry-picked from lede/openwrt tree https://git.lede-project.org/?p=source.git. Build tested for ARCH=arm64 + defconfig
It is part of a clean-up series but it holds good on it's own as well. I think. https://patchwork.ozlabs.org/cover/868855/
Cleanly apply on 4.9.y as well but since lede stopped supporting v4.9.y, I'm not sure if this patch is tested on v4.9.y at all.
drivers/i2c/busses/i2c-qup.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c index 08f8e0107642..8f6903ec7aec 100644 --- a/drivers/i2c/busses/i2c-qup.c +++ b/drivers/i2c/busses/i2c-qup.c @@ -844,6 +844,8 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg, }
if (ret || qup->bus_err || qup->qup_err) { + reinit_completion(&qup->xfer); + if (qup_i2c_change_state(qup, QUP_RUN_STATE)) { dev_err(qup->dev, "change to run state timed out"); goto desc_err;