1 files changed, 99 insertions, 64 deletions

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index d3b5261ee80a..a72d6d9fb983 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -1,6 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2017-2018, The Linux foundation. All rights reserved.
 
+#if defined(CONFIG_SERIAL_QCOM_GENI_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+# define SUPPORT_SYSRQ
+#endif
+
 #include <linux/clk.h>
 #include <linux/console.h>
 #include <linux/io.h>
@@ -89,9 +93,9 @@
 #define MAX_LOOPBACK_CFG	3
 
 #ifdef CONFIG_CONSOLE_POLL
-#define RX_BYTES_PW 1
+#define CONSOLE_RX_BYTES_PW 1
 #else
-#define RX_BYTES_PW 4
+#define CONSOLE_RX_BYTES_PW 4
 #endif
 
 struct qcom_geni_serial_port {
@@ -113,6 +117,8 @@ struct qcom_geni_serial_port {
 	u32 *rx_fifo;
 	u32 loopback;
 	bool brk;
+
+	unsigned int tx_remaining;
 };
 
 static const struct uart_ops qcom_geni_console_pops;
@@ -162,8 +168,7 @@ static struct qcom_geni_serial_port qcom_geni_uart_ports[GENI_UART_PORTS] = {
 static ssize_t loopback_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
-	struct platform_device *pdev = to_platform_device(dev);
-	struct qcom_geni_serial_port *port = platform_get_drvdata(pdev);
+	struct qcom_geni_serial_port *port = dev_get_drvdata(dev);
 
 	return snprintf(buf, sizeof(u32), "%d\n", port->loopback);
 }
@@ -172,8 +177,7 @@ static ssize_t loopback_store(struct device *dev,
 				struct device_attribute *attr, const char *buf,
 				size_t size)
 {
-	struct platform_device *pdev = to_platform_device(dev);
-	struct qcom_geni_serial_port *port = platform_get_drvdata(pdev);
+	struct qcom_geni_serial_port *port = dev_get_drvdata(dev);
 	u32 loopback;
 
 	if (kstrtoint(buf, 0, &loopback) || loopback > MAX_LOOPBACK_CFG) {
@@ -435,6 +439,8 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s,
 	struct qcom_geni_serial_port *port;
 	bool locked = true;
 	unsigned long flags;
+	u32 geni_status;
+	u32 irq_en;
 
 	WARN_ON(co->index < 0 || co->index >= GENI_UART_CONS_PORTS);
 
@@ -448,6 +454,8 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s,
 	else
 		spin_lock_irqsave(&uport->lock, flags);
 
+	geni_status = readl_relaxed(uport->membase + SE_GENI_STATUS);
+
 	/* Cancel the current write to log the fault */
 	if (!locked) {
 		geni_se_cancel_m_cmd(&port->se);
@@ -461,9 +469,26 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s,
 		}
 		writel_relaxed(M_CMD_CANCEL_EN, uport->membase +
 							SE_GENI_M_IRQ_CLEAR);
+	} else if ((geni_status & M_GENI_CMD_ACTIVE) && !port->tx_remaining) {
+		/*
+		 * It seems we can't interrupt existing transfers if all data
+		 * has been sent, in which case we need to look for done first.
+		 */
+		qcom_geni_serial_poll_tx_done(uport);
+
+		if (uart_circ_chars_pending(&uport->state->xmit)) {
+			irq_en = readl_relaxed(uport->membase +
+					SE_GENI_M_IRQ_EN);
+			writel_relaxed(irq_en | M_TX_FIFO_WATERMARK_EN,
+					uport->membase + SE_GENI_M_IRQ_EN);
+		}
 	}
 
 	__qcom_geni_serial_console_write(uport, s, count);
+
+	if (port->tx_remaining)
+		qcom_geni_serial_setup_tx(uport, port->tx_remaining);
+
 	if (locked)
 		spin_unlock_irqrestore(&uport->lock, flags);
 }
@@ -495,7 +520,8 @@ static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
 					continue;
 			}
 
-			sysrq = uart_handle_sysrq_char(uport, buf[c]);
+			sysrq = uart_prepare_sysrq_char(uport, buf[c]);
+
 			if (!sysrq)
 				tty_insert_flip_char(tport, buf[c], TTY_NORMAL);
 		}
@@ -694,40 +720,51 @@ static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop)
 	port->handle_rx(uport, total_bytes, drop);
 }
 
-static void qcom_geni_serial_handle_tx(struct uart_port *uport)
+static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
+		bool active)
 {
 	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
 	struct circ_buf *xmit = &uport->state->xmit;
 	size_t avail;
 	size_t remaining;
+	size_t pending;
 	int i;
 	u32 status;
+	u32 irq_en;
 	unsigned int chunk;
 	int tail;
-	u32 irq_en;
 
-	chunk = uart_circ_chars_pending(xmit);
 	status = readl_relaxed(uport->membase + SE_GENI_TX_FIFO_STATUS);
-	/* Both FIFO and framework buffer are drained */
-	if (!chunk && !status) {
+
+	/* Complete the current tx command before taking newly added data */
+	if (active)
+		pending = port->tx_remaining;
+	else
+		pending = uart_circ_chars_pending(xmit);
+
+	/* All data has been transmitted and acknowledged as received */
+	if (!pending && !status && done) {
 		qcom_geni_serial_stop_tx(uport);
 		goto out_write_wakeup;
 	}
 
-	if (!uart_console(uport)) {
-		irq_en = readl_relaxed(uport->membase + SE_GENI_M_IRQ_EN);
-		irq_en &= ~(M_TX_FIFO_WATERMARK_EN);
-		writel_relaxed(0, uport->membase + SE_GENI_TX_WATERMARK_REG);
-		writel_relaxed(irq_en, uport->membase + SE_GENI_M_IRQ_EN);
-	}
+	avail = port->tx_fifo_depth - (status & TX_FIFO_WC);
+	avail *= port->tx_bytes_pw;
 
-	avail = (port->tx_fifo_depth - port->tx_wm) * port->tx_bytes_pw;
 	tail = xmit->tail;
-	chunk = min3((size_t)chunk, (size_t)(UART_XMIT_SIZE - tail), avail);
+	chunk = min(avail, pending);
 	if (!chunk)
 		goto out_write_wakeup;
 
-	qcom_geni_serial_setup_tx(uport, chunk);
+	if (!port->tx_remaining) {
+		qcom_geni_serial_setup_tx(uport, pending);
+		port->tx_remaining = pending;
+
+		irq_en = readl_relaxed(uport->membase + SE_GENI_M_IRQ_EN);
+		if (!(irq_en & M_TX_FIFO_WATERMARK_EN))
+			writel_relaxed(irq_en | M_TX_FIFO_WATERMARK_EN,
+					uport->membase + SE_GENI_M_IRQ_EN);
+	}
 
 	remaining = chunk;
 	for (i = 0; i < chunk; ) {
@@ -737,21 +774,38 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport)
 
 		memset(buf, 0, ARRAY_SIZE(buf));
 		tx_bytes = min_t(size_t, remaining, port->tx_bytes_pw);
-		for (c = 0; c < tx_bytes ; c++)
-			buf[c] = xmit->buf[tail + c];
+
+		for (c = 0; c < tx_bytes ; c++) {
+			buf[c] = xmit->buf[tail++];
+			tail &= UART_XMIT_SIZE - 1;
+		}
 
 		iowrite32_rep(uport->membase + SE_GENI_TX_FIFOn, buf, 1);
 
 		i += tx_bytes;
-		tail += tx_bytes;
 		uport->icount.tx += tx_bytes;
 		remaining -= tx_bytes;
+		port->tx_remaining -= tx_bytes;
 	}
 
-	xmit->tail = tail & (UART_XMIT_SIZE - 1);
-	if (uart_console(uport))
-		qcom_geni_serial_poll_tx_done(uport);
+	xmit->tail = tail;
+
+	/*
+	 * The tx fifo watermark is level triggered and latched. Though we had
+	 * cleared it in qcom_geni_serial_isr it will have already reasserted
+	 * so we must clear it again here after our writes.
+	 */
+	writel_relaxed(M_TX_FIFO_WATERMARK_EN,
+			uport->membase + SE_GENI_M_IRQ_CLEAR);
+
 out_write_wakeup:
+	if (!port->tx_remaining) {
+		irq_en = readl_relaxed(uport->membase + SE_GENI_M_IRQ_EN);
+		if (irq_en & M_TX_FIFO_WATERMARK_EN)
+			writel_relaxed(irq_en & ~M_TX_FIFO_WATERMARK_EN,
+					uport->membase + SE_GENI_M_IRQ_EN);
+	}
+
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(uport);
 }
@@ -760,6 +814,7 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 {
 	unsigned int m_irq_status;
 	unsigned int s_irq_status;
+	unsigned int geni_status;
 	struct uart_port *uport = dev;
 	unsigned long flags;
 	unsigned int m_irq_en;
@@ -773,6 +828,7 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 	spin_lock_irqsave(&uport->lock, flags);
 	m_irq_status = readl_relaxed(uport->membase + SE_GENI_M_IRQ_STATUS);
 	s_irq_status = readl_relaxed(uport->membase + SE_GENI_S_IRQ_STATUS);
+	geni_status = readl_relaxed(uport->membase + SE_GENI_STATUS);
 	m_irq_en = readl_relaxed(uport->membase + SE_GENI_M_IRQ_EN);
 	writel_relaxed(m_irq_status, uport->membase + SE_GENI_M_IRQ_CLEAR);
 	writel_relaxed(s_irq_status, uport->membase + SE_GENI_S_IRQ_CLEAR);
@@ -785,9 +841,9 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 		tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 	}
 
-	if (m_irq_status & (M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN) &&
-	    m_irq_en & (M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN))
-		qcom_geni_serial_handle_tx(uport);
+	if (m_irq_status & m_irq_en & (M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN))
+		qcom_geni_serial_handle_tx(uport, m_irq_status & M_CMD_DONE_EN,
+					geni_status & M_GENI_CMD_ACTIVE);
 
 	if (s_irq_status & S_GP_IRQ_0_EN || s_irq_status & S_GP_IRQ_1_EN) {
 		if (s_irq_status & S_GP_IRQ_0_EN)
@@ -804,7 +860,8 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 		qcom_geni_serial_handle_rx(uport, drop_rx);
 
 out_unlock:
-	spin_unlock_irqrestore(&uport->lock, flags);
+	uart_unlock_and_check_sysrq(uport, flags);
+
 	return IRQ_HANDLED;
 }
 
@@ -853,11 +910,13 @@ static int qcom_geni_serial_port_setup(struct uart_port *uport)
 	unsigned int rxstale = DEFAULT_BITS_PER_CHAR * STALE_TIMEOUT;
 	u32 proto;
 
-	if (uart_console(uport))
+	if (uart_console(uport)) {
 		port->tx_bytes_pw = 1;
-	else
+		port->rx_bytes_pw = CONSOLE_RX_BYTES_PW;
+	} else {
 		port->tx_bytes_pw = 4;
-	port->rx_bytes_pw = RX_BYTES_PW;
+		port->rx_bytes_pw = 4;
+	}
 
 	proto = geni_se_read_proto(&port->se);
 	if (proto != GENI_SE_UART) {
@@ -1322,49 +1381,25 @@ static int qcom_geni_serial_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static int __maybe_unused qcom_geni_serial_sys_suspend_noirq(struct device *dev)
+static int __maybe_unused qcom_geni_serial_sys_suspend(struct device *dev)
 {
 	struct qcom_geni_serial_port *port = dev_get_drvdata(dev);
 	struct uart_port *uport = &port->uport;
 
-	if (uart_console(uport)) {
-		uart_suspend_port(uport->private_data, uport);
-	} else {
-		struct uart_state *state = uport->state;
-		/*
-		 * If the port is open, deny system suspend.
-		 */
-		if (state->pm_state == UART_PM_STATE_ON)
-			return -EBUSY;
-	}
-
-	return 0;
+	return uart_suspend_port(uport->private_data, uport);
 }
 
-static int __maybe_unused qcom_geni_serial_sys_resume_noirq(struct device *dev)
+static int __maybe_unused qcom_geni_serial_sys_resume(struct device *dev)
 {
 	struct qcom_geni_serial_port *port = dev_get_drvdata(dev);
 	struct uart_port *uport = &port->uport;
 
-	if (uart_console(uport) &&
-			console_suspend_enabled && uport->suspended) {
-		uart_resume_port(uport->private_data, uport);
-		/*
-		 * uart_suspend_port() invokes port shutdown which in turn
-		 * frees the irq. uart_resume_port invokes port startup which
-		 * performs request_irq. The request_irq auto-enables the IRQ.
-		 * In addition, resume_noirq implicitly enables the IRQ and
-		 * leads to an unbalanced IRQ enable warning. Disable the IRQ
-		 * before returning so that the warning is suppressed.
-		 */
-		disable_irq(uport->irq);
-	}
-	return 0;
+	return uart_resume_port(uport->private_data, uport);
 }
 
 static const struct dev_pm_ops qcom_geni_serial_pm_ops = {
-	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(qcom_geni_serial_sys_suspend_noirq,
-					qcom_geni_serial_sys_resume_noirq)
+	SET_SYSTEM_SLEEP_PM_OPS(qcom_geni_serial_sys_suspend,
+					qcom_geni_serial_sys_resume)
 };
 
 static const struct of_device_id qcom_geni_serial_match_table[] = {