The patch titled
atmel_serial: Avoid stopping pdc during transmission
has been added to the -mm tree. Its filename is
atmel_serial-avoid-stopping-pdc-during-transmission.patch
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Subject: atmel_serial: Avoid stopping pdc during transmission
From: Michael Trimarchi <trimarchimichael@xxxxxxxx>
I found a problem related to loosing data during pdc trasmission in the
atmel_serial. For now this patch seems to work for me, but I think that is
not the better solution. I do this test:
- connect ttyS1 with ttyS2 using a loopback cable, send 30 byte of packet from
one to the other and waiting for 30 byte. On the other side just read and
echo the data received.
Signed-off-by: michael <trimarchi@xxxxxxxxxxxxxxxx>
Cc: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/serial/atmel_serial.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff -puN drivers/serial/atmel_serial.c~atmel_serial-avoid-stopping-pdc-during-transmission drivers/serial/atmel_serial.c
--- a/drivers/serial/atmel_serial.c~atmel_serial-avoid-stopping-pdc-during-transmission
+++ a/drivers/serial/atmel_serial.c
@@ -96,6 +96,7 @@
/* PDC registers */
#define UART_PUT_PTCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)
+#define UART_GET_TCR(port) __raw_readl((port)->membase + ATMEL_PDC_TCR)
#define UART_GET_PTSR(port) __raw_readl((port)->membase + ATMEL_PDC_PTSR)
#define UART_PUT_RPR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_RPR)
@@ -568,11 +569,16 @@ static void atmel_tx_dma(struct uart_por
port->icount.tx += pdc->ofs;
pdc->ofs = 0;
- if (!uart_circ_empty(xmit)) {
- /* more to transmit - setup next transfer */
+ /* more to transmit - setup next transfer */
- /* disable PDC transmit */
- UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
+ /* nothing left to transmit? */
+ while (UART_GET_TCR(port))
+ cpu_relax();
+
+ /* disable PDC transmit */
+ UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
+
+ if (!uart_circ_empty(xmit)) {
dma_sync_single_for_device(port->dev,
pdc->dma_addr,
pdc->dma_size,
@@ -586,11 +592,6 @@ static void atmel_tx_dma(struct uart_por
/* re-enable PDC transmit and interrupts */
UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);
UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
- } else {
- /* nothing left to transmit - disable the transmitter */
-
- /* disable PDC transmit */
- UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
_
Patches currently in -mm which might be from trimarchimichael@xxxxxxxx are
atmel_serial-avoid-stopping-pdc-during-transmission.patch
jffs2-add-write-verify-on-dataflash.patch
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