From 4cc0ed626f2ba36cd008d4b380613f0360133891 Mon Sep 17 00:00:00 2001 From: Erwan Le Ray Date: Tue, 18 Jun 2019 12:02:22 +0200 Subject: [PATCH] serial: stm32: add support of timeout interrupt for RX Add support of RX timeout interrupts to limit the number of interrupts. RX timeout is a number of bits (baud clock cycles) without transmission seen in the receiver. One character is used as an arbitrary RX timeout value. If parity is enabled, the number of bits has to include parity bit. Signed-off-by: Gerald Baeza Signed-off-by: Fabrice Gasnier Signed-off-by: Erwan Le Ray Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 31 +++++++++++++++++++++++++------ drivers/tty/serial/stm32-usart.h | 1 + 2 files changed, 26 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index c6a9293..2e75b58 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -434,6 +434,10 @@ static irqreturn_t stm32_interrupt(int irq, void *ptr) sr = readl_relaxed(port->membase + ofs->isr); + if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) + writel_relaxed(USART_ICR_RTOCF, + port->membase + ofs->icr); + if ((sr & USART_SR_WUF) && (ofs->icr != UNDEF_REG)) writel_relaxed(USART_ICR_WUCF, port->membase + ofs->icr); @@ -520,7 +524,7 @@ static void stm32_throttle(struct uart_port *port) unsigned long flags; spin_lock_irqsave(&port->lock, flags); - stm32_clr_bits(port, ofs->cr1, USART_CR1_RXNEIE); + stm32_clr_bits(port, ofs->cr1, stm32_port->cr1_irq); spin_unlock_irqrestore(&port->lock, flags); } @@ -532,7 +536,7 @@ static void stm32_unthrottle(struct uart_port *port) unsigned long flags; spin_lock_irqsave(&port->lock, flags); - stm32_set_bits(port, ofs->cr1, USART_CR1_RXNEIE); + stm32_set_bits(port, ofs->cr1, stm32_port->cr1_irq); spin_unlock_irqrestore(&port->lock, flags); } @@ -542,7 +546,7 @@ static void stm32_stop_rx(struct uart_port *port) struct stm32_port *stm32_port = to_stm32_port(port); struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - stm32_clr_bits(port, ofs->cr1, USART_CR1_RXNEIE); + stm32_clr_bits(port, ofs->cr1, stm32_port->cr1_irq); } /* Handle breaks - ignored by us */ @@ -564,7 +568,7 @@ static int stm32_startup(struct uart_port *port) if (ret) return ret; - val = USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE; + val = stm32_port->cr1_irq | USART_CR1_TE | USART_CR1_RE; if (stm32_port->fifoen) val |= USART_CR1_FIFOEN; stm32_set_bits(port, ofs->cr1, val); @@ -580,7 +584,8 @@ static void stm32_shutdown(struct uart_port *port) u32 val, isr; int ret; - val = USART_CR1_TXEIE | USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE; + val = USART_CR1_TXEIE | USART_CR1_TE; + val |= stm32_port->cr1_irq | USART_CR1_RE; val |= BIT(cfg->uart_enable_bit); if (stm32_port->fifoen) val |= USART_CR1_FIFOEN; @@ -650,7 +655,7 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios, /* Stop serial port and reset value */ writel_relaxed(0, port->membase + ofs->cr1); - cr1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE; + cr1 = USART_CR1_TE | USART_CR1_RE; if (stm32_port->fifoen) cr1 |= USART_CR1_FIFOEN; @@ -683,6 +688,19 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios, dev_dbg(port->dev, "Unsupported data bits config: %u bits\n" , bits); + if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch || + stm32_port->fifoen)) { + if (cflag & CSTOPB) + bits = bits + 3; /* 1 start bit + 2 stop bits */ + else + bits = bits + 2; /* 1 start bit + 1 stop bit */ + + /* RX timeout irq to occur after last stop bit + bits */ + stm32_port->cr1_irq = USART_CR1_RTOIE; + writel_relaxed(bits, port->membase + ofs->rtor); + cr2 |= USART_CR2_RTOEN; + } + if (cflag & PARODD) cr1 |= USART_CR1_PS; @@ -922,6 +940,7 @@ static struct stm32_port *stm32_of_get_stm32_port(struct platform_device *pdev) stm32_ports[id].hw_flow_control = of_property_read_bool(np, "st,hw-flow-ctrl"); stm32_ports[id].port.line = id; + stm32_ports[id].cr1_irq = USART_CR1_RXNEIE; stm32_ports[id].last_res = RX_BUF_L; return &stm32_ports[id]; } diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h index 30d2433..fcd01fe 100644 --- a/drivers/tty/serial/stm32-usart.h +++ b/drivers/tty/serial/stm32-usart.h @@ -249,6 +249,7 @@ struct stm32_port { struct dma_chan *tx_ch; /* dma tx channel */ dma_addr_t tx_dma_buf; /* dma tx buffer bus address */ unsigned char *tx_buf; /* dma tx buffer cpu address */ + u32 cr1_irq; /* USART_CR1_RXNEIE or RTOIE */ int last_res; bool tx_dma_busy; /* dma tx busy */ bool hw_flow_control; -- 2.7.4