1 files changed, 187 insertions, 38 deletions

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 87b5cd4c9743..b7b44f4050d4 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -37,6 +37,7 @@
 
 static void stm32_usart_stop_tx(struct uart_port *port);
 static void stm32_usart_transmit_chars(struct uart_port *port);
+static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch);
 
 static inline struct stm32_port *to_stm32_port(struct uart_port *port)
 {
@@ -107,8 +108,6 @@ static int stm32_usart_config_rs485(struct uart_port *port,
 
 	stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 
-	port->rs485 = *rs485conf;
-
 	rs485conf->flags |= SER_RS485_RX_DURING_TX;
 
 	if (rs485conf->flags & SER_RS485_ENABLED) {
@@ -128,13 +127,10 @@ static int stm32_usart_config_rs485(struct uart_port *port,
 					     rs485conf->delay_rts_after_send,
 					     baud);
 
-		if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
+		if (rs485conf->flags & SER_RS485_RTS_ON_SEND)
 			cr3 &= ~USART_CR3_DEP;
-			rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
-		} else {
+		else
 			cr3 |= USART_CR3_DEP;
-			rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
-		}
 
 		writel_relaxed(cr3, port->membase + ofs->cr3);
 		writel_relaxed(cr1, port->membase + ofs->cr1);
@@ -421,6 +417,14 @@ static void stm32_usart_tx_interrupt_enable(struct uart_port *port)
 		stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
 }
 
+static void stm32_usart_tc_interrupt_enable(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+	stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TCIE);
+}
+
 static void stm32_usart_rx_dma_complete(void *arg)
 {
 	struct uart_port *port = arg;
@@ -446,6 +450,50 @@ static void stm32_usart_tx_interrupt_disable(struct uart_port *port)
 		stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
 }
 
+static void stm32_usart_tc_interrupt_disable(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+	stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TCIE);
+}
+
+static void stm32_usart_rs485_rts_enable(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	struct serial_rs485 *rs485conf = &port->rs485;
+
+	if (stm32_port->hw_flow_control ||
+	    !(rs485conf->flags & SER_RS485_ENABLED))
+		return;
+
+	if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
+		mctrl_gpio_set(stm32_port->gpios,
+			       stm32_port->port.mctrl | TIOCM_RTS);
+	} else {
+		mctrl_gpio_set(stm32_port->gpios,
+			       stm32_port->port.mctrl & ~TIOCM_RTS);
+	}
+}
+
+static void stm32_usart_rs485_rts_disable(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	struct serial_rs485 *rs485conf = &port->rs485;
+
+	if (stm32_port->hw_flow_control ||
+	    !(rs485conf->flags & SER_RS485_ENABLED))
+		return;
+
+	if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
+		mctrl_gpio_set(stm32_port->gpios,
+			       stm32_port->port.mctrl & ~TIOCM_RTS);
+	} else {
+		mctrl_gpio_set(stm32_port->gpios,
+			       stm32_port->port.mctrl | TIOCM_RTS);
+	}
+}
+
 static void stm32_usart_transmit_chars_pio(struct uart_port *port)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
@@ -553,6 +601,13 @@ static void stm32_usart_transmit_chars(struct uart_port *port)
 	u32 isr;
 	int ret;
 
+	if (!stm32_port->hw_flow_control &&
+	    port->rs485.flags & SER_RS485_ENABLED) {
+		stm32_port->txdone = false;
+		stm32_usart_tc_interrupt_disable(port);
+		stm32_usart_rs485_rts_enable(port);
+	}
+
 	if (port->x_char) {
 		if (stm32_usart_tx_dma_started(stm32_port) &&
 		    stm32_usart_tx_dma_enabled(stm32_port))
@@ -593,8 +648,14 @@ static void stm32_usart_transmit_chars(struct uart_port *port)
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(port);
 
-	if (uart_circ_empty(xmit))
+	if (uart_circ_empty(xmit)) {
 		stm32_usart_tx_interrupt_disable(port);
+		if (!stm32_port->hw_flow_control &&
+		    port->rs485.flags & SER_RS485_ENABLED) {
+			stm32_port->txdone = true;
+			stm32_usart_tc_interrupt_enable(port);
+		}
+	}
 }
 
 static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
@@ -608,6 +669,13 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 
 	sr = readl_relaxed(port->membase + ofs->isr);
 
+	if (!stm32_port->hw_flow_control &&
+	    port->rs485.flags & SER_RS485_ENABLED &&
+	    (sr & USART_SR_TC)) {
+		stm32_usart_tc_interrupt_disable(port);
+		stm32_usart_rs485_rts_disable(port);
+	}
+
 	if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
 		writel_relaxed(USART_ICR_RTOCF,
 			       port->membase + ofs->icr);
@@ -717,44 +785,27 @@ static void stm32_usart_disable_ms(struct uart_port *port)
 static void stm32_usart_stop_tx(struct uart_port *port)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
-	struct serial_rs485 *rs485conf = &port->rs485;
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
 	stm32_usart_tx_interrupt_disable(port);
 	if (stm32_usart_tx_dma_started(stm32_port) && stm32_usart_tx_dma_enabled(stm32_port))
 		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 
-	if (rs485conf->flags & SER_RS485_ENABLED) {
-		if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
-			mctrl_gpio_set(stm32_port->gpios,
-					stm32_port->port.mctrl & ~TIOCM_RTS);
-		} else {
-			mctrl_gpio_set(stm32_port->gpios,
-					stm32_port->port.mctrl | TIOCM_RTS);
-		}
-	}
+	stm32_usart_rs485_rts_disable(port);
 }
 
 /* There are probably characters waiting to be transmitted. */
 static void stm32_usart_start_tx(struct uart_port *port)
 {
-	struct stm32_port *stm32_port = to_stm32_port(port);
-	struct serial_rs485 *rs485conf = &port->rs485;
 	struct circ_buf *xmit = &port->state->xmit;
 
-	if (uart_circ_empty(xmit) && !port->x_char)
+	if (uart_circ_empty(xmit) && !port->x_char) {
+		stm32_usart_rs485_rts_disable(port);
 		return;
-
-	if (rs485conf->flags & SER_RS485_ENABLED) {
-		if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
-			mctrl_gpio_set(stm32_port->gpios,
-					stm32_port->port.mctrl | TIOCM_RTS);
-		} else {
-			mctrl_gpio_set(stm32_port->gpios,
-					stm32_port->port.mctrl & ~TIOCM_RTS);
-		}
 	}
 
+	stm32_usart_rs485_rts_enable(port);
+
 	stm32_usart_transmit_chars(port);
 }
 
@@ -1037,13 +1088,22 @@ static void stm32_usart_set_termios(struct uart_port *port,
 	 * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
 	 * M0 and M1 already cleared by cr1 initialization.
 	 */
-	if (bits == 9)
+	if (bits == 9) {
 		cr1 |= USART_CR1_M0;
-	else if ((bits == 7) && cfg->has_7bits_data)
+	} else if ((bits == 7) && cfg->has_7bits_data) {
 		cr1 |= USART_CR1_M1;
-	else if (bits != 8)
+	} else if (bits != 8) {
 		dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
 			, bits);
+		cflag &= ~CSIZE;
+		cflag |= CS8;
+		termios->c_cflag = cflag;
+		bits = 8;
+		if (cflag & PARENB) {
+			bits++;
+			cr1 |= USART_CR1_M0;
+		}
+	}
 
 	if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
 				       (stm32_port->fifoen &&
@@ -1222,6 +1282,33 @@ static void stm32_usart_pm(struct uart_port *port, unsigned int state,
 	}
 }
 
+#if defined(CONFIG_CONSOLE_POLL)
+
+ /* Callbacks for characters polling in debug context (i.e. KGDB). */
+static int stm32_usart_poll_init(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+
+	return clk_prepare_enable(stm32_port->clk);
+}
+
+static int stm32_usart_poll_get_char(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+	if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_RXNE))
+		return NO_POLL_CHAR;
+
+	return readl_relaxed(port->membase + ofs->rdr) & stm32_port->rdr_mask;
+}
+
+static void stm32_usart_poll_put_char(struct uart_port *port, unsigned char ch)
+{
+	stm32_usart_console_putchar(port, ch);
+}
+#endif /* CONFIG_CONSOLE_POLL */
+
 static const struct uart_ops stm32_uart_ops = {
 	.tx_empty	= stm32_usart_tx_empty,
 	.set_mctrl	= stm32_usart_set_mctrl,
@@ -1243,6 +1330,11 @@ static const struct uart_ops stm32_uart_ops = {
 	.request_port	= stm32_usart_request_port,
 	.config_port	= stm32_usart_config_port,
 	.verify_port	= stm32_usart_verify_port,
+#if defined(CONFIG_CONSOLE_POLL)
+	.poll_init      = stm32_usart_poll_init,
+	.poll_get_char	= stm32_usart_poll_get_char,
+	.poll_put_char	= stm32_usart_poll_put_char,
+#endif /* CONFIG_CONSOLE_POLL */
 };
 
 /*
@@ -1640,18 +1732,24 @@ static int stm32_usart_serial_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_SERIAL_STM32_CONSOLE
-static void stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
+static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+	u32 isr;
+	int ret;
 
-	while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
-		cpu_relax();
-
+	ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, isr,
+						(isr & USART_SR_TXE), 100,
+						STM32_USART_TIMEOUT_USEC);
+	if (ret != 0) {
+		dev_err(port->dev, "Error while sending data in UART TX : %d\n", ret);
+		return;
+	}
 	writel_relaxed(ch, port->membase + ofs->tdr);
 }
 
+#ifdef CONFIG_SERIAL_STM32_CONSOLE
 static void stm32_usart_console_write(struct console *co, const char *s,
 				      unsigned int cnt)
 {
@@ -1727,6 +1825,57 @@ static struct console stm32_console = {
 #define STM32_SERIAL_CONSOLE NULL
 #endif /* CONFIG_SERIAL_STM32_CONSOLE */
 
+#ifdef CONFIG_SERIAL_EARLYCON
+static void early_stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
+{
+	struct stm32_usart_info *info = port->private_data;
+
+	while (!(readl_relaxed(port->membase + info->ofs.isr) & USART_SR_TXE))
+		cpu_relax();
+
+	writel_relaxed(ch, port->membase + info->ofs.tdr);
+}
+
+static void early_stm32_serial_write(struct console *console, const char *s, unsigned int count)
+{
+	struct earlycon_device *device = console->data;
+	struct uart_port *port = &device->port;
+
+	uart_console_write(port, s, count, early_stm32_usart_console_putchar);
+}
+
+static int __init early_stm32_h7_serial_setup(struct earlycon_device *device, const char *options)
+{
+	if (!(device->port.membase || device->port.iobase))
+		return -ENODEV;
+	device->port.private_data = &stm32h7_info;
+	device->con->write = early_stm32_serial_write;
+	return 0;
+}
+
+static int __init early_stm32_f7_serial_setup(struct earlycon_device *device, const char *options)
+{
+	if (!(device->port.membase || device->port.iobase))
+		return -ENODEV;
+	device->port.private_data = &stm32f7_info;
+	device->con->write = early_stm32_serial_write;
+	return 0;
+}
+
+static int __init early_stm32_f4_serial_setup(struct earlycon_device *device, const char *options)
+{
+	if (!(device->port.membase || device->port.iobase))
+		return -ENODEV;
+	device->port.private_data = &stm32f4_info;
+	device->con->write = early_stm32_serial_write;
+	return 0;
+}
+
+OF_EARLYCON_DECLARE(stm32, "st,stm32h7-uart", early_stm32_h7_serial_setup);
+OF_EARLYCON_DECLARE(stm32, "st,stm32f7-uart", early_stm32_f7_serial_setup);
+OF_EARLYCON_DECLARE(stm32, "st,stm32-uart", early_stm32_f4_serial_setup);
+#endif /* CONFIG_SERIAL_EARLYCON */
+
 static struct uart_driver stm32_usart_driver = {
 	.driver_name	= DRIVER_NAME,
 	.dev_name	= STM32_SERIAL_NAME,