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tty: serial: msm: Don't read off end of tx fifo

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For dm uarts in pio mode tx data is transferred to the fifo register 4
bytes at a time, but care is not taken when these 4 bytes spans the end
of the xmit buffer so the loop might read up to 3 bytes past the buffer
and then skip the actual data at the beginning of the buffer.

Fix this by, analogous to the DMA case, make sure the chunk doesn't
wrap the xmit buffer.

CRs-Fixed: 1053499
Change-Id: Ia6127c3a18e8909171c4b24c633e361245d1ed72
Fixes: 3a878c430f ("tty: serial: msm: Add TX DMA support")
Cc: Ivan Ivanov <iivanov.xz@gmail.com>
Cc: stable@vger.kernel.org
Reported-by: Frank Rowand <frowand.list@gmail.com>
Reported-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Andy Gross <andy.gross@linaro.org>
Tested-by: Frank Rowand <frank.rowand@am.sony.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: 30acf549ca1e81859a67590ab9ecfce3d1050a0b
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
This commit is contained in:
Bjorn Andersson 2016-06-02 17:48:28 -07:00 • committed by Satya Durga Srinivasu Prabhala
parent bca0ca6799
commit 965faeecbb
1 changed files with 1 additions and 1 deletions
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2
drivers/tty/serial/msm_serial.c
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@ -891,7 +891,7 @@ static void msm_handle_tx(struct uart_port *port)
return;
}
pio_count = CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE);
pio_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
dma_min = 1; /* Always DMA */