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serial: stm32: Add support of TC bit status check

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Adds a check on the Transmission Complete bit status before closing the
com port. Prevents the port closure before the end of the transmission.
TC poll loop is moved from stm32_tx_dma_complete to stm32_shutdown
routine, in order to check TC before shutdown in both dma and
PIO tx modes.
TC clear is added in stm32_transmit_char routine, in order to be cleared
before transmitting in both dma and PIO tx modes.

Fixes: 3489187204 ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Erwan Le Ray 2019-05-21 17:45:45 +02:00 committed by Greg Kroah-Hartman
parent b83b957c91
commit 64c32eab66
1 changed files with 15 additions and 17 deletions
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32
drivers/tty/serial/stm32-usart.c
View file

@ -290,21 +290,6 @@ static void stm32_tx_dma_complete(void *arg)
struct uart_port *port = arg;
struct stm32_port *stm32port = to_stm32_port(port);
struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
unsigned int isr;
int ret;
ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
isr,
(isr & USART_SR_TC),
10, 100000);
if (ret)
dev_err(port->dev, "terminal count not set\n");
if (ofs->icr == UNDEF_REG)
stm32_clr_bits(port, ofs->isr, USART_SR_TC);
else
stm32_set_bits(port, ofs->icr, USART_CR_TC);
stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
stm32port->tx_dma_busy = false;
@ -396,7 +381,6 @@ static void stm32_transmit_chars_dma(struct uart_port *port)
/* Issue pending DMA TX requests */
dma_async_issue_pending(stm32port->tx_ch);
stm32_clr_bits(port, ofs->isr, USART_SR_TC);
stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);
xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
@ -425,6 +409,11 @@ static void stm32_transmit_chars(struct uart_port *port)
return;
}
if (ofs->icr == UNDEF_REG)
stm32_clr_bits(port, ofs->isr, USART_SR_TC);
else
stm32_set_bits(port, ofs->icr, USART_ICR_TCCF);
if (stm32_port->tx_ch)
stm32_transmit_chars_dma(port);
else
@ -601,12 +590,21 @@ static void stm32_shutdown(struct uart_port *port)
struct stm32_port *stm32_port = to_stm32_port(port);
struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
struct stm32_usart_config *cfg = &stm32_port->info->cfg;
u32 val;
u32 val, isr;
int ret;
val = USART_CR1_TXEIE | USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE;
val |= BIT(cfg->uart_enable_bit);
if (stm32_port->fifoen)
val |= USART_CR1_FIFOEN;
ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,
isr, (isr & USART_SR_TC),
10, 100000);
if (ret)
dev_err(port->dev, "transmission complete not set\n");
stm32_clr_bits(port, ofs->cr1, val);
dev_pm_clear_wake_irq(port->dev);