| Message ID | 1451949681-23804-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c index 5c06168..2933626 100644 --- a/drivers/spi/spi-ti-qspi.c +++ b/drivers/spi/spi-ti-qspi.c @@ -384,11 +384,10 @@ static int ti_qspi_start_transfer_one(struct spi_master *master, mutex_unlock(&qspi->list_lock); + ti_qspi_write(qspi, qspi->cmd | QSPI_INVAL, QSPI_SPI_CMD_REG); m->status = status; spi_finalize_current_message(master); - ti_qspi_write(qspi, qspi->cmd | QSPI_INVAL, QSPI_SPI_CMD_REG); - return status; }
This is a note to let you know that I have just added a patch titled spi: ti-qspi: Fix data corruption seen on r/w stress test to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt1. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 85838097b4ff4053634ea496e09c8bc18d2c3f6b Mon Sep 17 00:00:00 2001 From: Vignesh R <vigneshr@ti.com> Date: Mon, 12 Oct 2015 13:22:02 +0530 Subject: spi: ti-qspi: Fix data corruption seen on r/w stress test commit bc27a53928981662079aa243915b443370294a03 upstream. Writing invalid command to QSPI_SPI_CMD_REG will terminate current transfer and de-assert the chip select. This has to be done before calling spi_finalize_current_message(). Because spi_finalize_current_message() will mark the end of current message transfer and schedule the next transfer. If the chipselect is not de-asserted before calling spi_finalize_current_message() then the next transfer will overlap with the previous transfer leading to data corruption. __spi_pump_message() can be called either from kthread worker context or directly from the calling process's context. It is possible that these two calls can race against each other. But race is serialized by checking whether master->cur_msg == NULL (pointer to msg being handled by transfer_one() at present). The master->cur_msg is set to NULL when spi_finalize_current_message() is called on that message, which means calling spi_finalize_current_message() allows __spi_sync() to pump next message in calling process context. Now if spi-ti-qspi calls spi_finalize_current_message() before we terminate transfer at hardware side, if __spi_pump_message() is called from process context then the successive transactions can overlap. Fix this by moving writing invalid command to QSPI_SPI_CMD_REG to before calling spi_finalize_current_message() call. Signed-off-by: Vignesh R <vigneshr@ti.com> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/spi/spi-ti-qspi.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) -- 1.9.1