Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1838 insertions, 0 deletions

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
new file mode 100644
index 0000000000..346167afe9
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -0,0 +1,1838 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 8250-core based driver for the OMAP internal UART
+ *
+ * based on omap-serial.c, Copyright (C) 2010 Texas Instruments.
+ *
+ * Copyright (C) 2014 Sebastian Andrzej Siewior
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/serial_8250.h>
+#include <linux/serial_reg.h>
+#include <linux/tty_flip.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/of_irq.h>
+#include <linux/delay.h>
+#include <linux/pm_runtime.h>
+#include <linux/console.h>
+#include <linux/pm_qos.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/dma-mapping.h>
+#include <linux/sys_soc.h>
+
+#include "8250.h"
+
+#define DEFAULT_CLK_SPEED	48000000
+#define OMAP_UART_REGSHIFT	2
+
+#define UART_ERRATA_i202_MDR1_ACCESS	(1 << 0)
+#define OMAP_UART_WER_HAS_TX_WAKEUP	(1 << 1)
+#define OMAP_DMA_TX_KICK		(1 << 2)
+/*
+ * See Advisory 21 in AM437x errata SPRZ408B, updated April 2015.
+ * The same errata is applicable to AM335x and DRA7x processors too.
+ */
+#define UART_ERRATA_CLOCK_DISABLE	(1 << 3)
+#define	UART_HAS_EFR2			BIT(4)
+#define UART_HAS_RHR_IT_DIS		BIT(5)
+#define UART_RX_TIMEOUT_QUIRK		BIT(6)
+#define UART_HAS_NATIVE_RS485		BIT(7)
+
+#define OMAP_UART_FCR_RX_TRIG		6
+#define OMAP_UART_FCR_TX_TRIG		4
+
+/* SCR register bitmasks */
+#define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK	(1 << 7)
+#define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK	(1 << 6)
+#define OMAP_UART_SCR_TX_EMPTY			(1 << 3)
+#define OMAP_UART_SCR_DMAMODE_MASK		(3 << 1)
+#define OMAP_UART_SCR_DMAMODE_1			(1 << 1)
+#define OMAP_UART_SCR_DMAMODE_CTL		(1 << 0)
+
+/* MVR register bitmasks */
+#define OMAP_UART_MVR_SCHEME_SHIFT	30
+#define OMAP_UART_LEGACY_MVR_MAJ_MASK	0xf0
+#define OMAP_UART_LEGACY_MVR_MAJ_SHIFT	4
+#define OMAP_UART_LEGACY_MVR_MIN_MASK	0x0f
+#define OMAP_UART_MVR_MAJ_MASK		0x700
+#define OMAP_UART_MVR_MAJ_SHIFT		8
+#define OMAP_UART_MVR_MIN_MASK		0x3f
+
+/* SYSC register bitmasks */
+#define OMAP_UART_SYSC_SOFTRESET	(1 << 1)
+
+/* SYSS register bitmasks */
+#define OMAP_UART_SYSS_RESETDONE	(1 << 0)
+
+#define UART_TI752_TLR_TX	0
+#define UART_TI752_TLR_RX	4
+
+#define TRIGGER_TLR_MASK(x)	((x & 0x3c) >> 2)
+#define TRIGGER_FCR_MASK(x)	(x & 3)
+
+/* Enable XON/XOFF flow control on output */
+#define OMAP_UART_SW_TX		0x08
+/* Enable XON/XOFF flow control on input */
+#define OMAP_UART_SW_RX		0x02
+
+#define OMAP_UART_WER_MOD_WKUP	0x7f
+#define OMAP_UART_TX_WAKEUP_EN	(1 << 7)
+
+#define TX_TRIGGER	1
+#define RX_TRIGGER	48
+
+#define OMAP_UART_TCR_RESTORE(x)	((x / 4) << 4)
+#define OMAP_UART_TCR_HALT(x)		((x / 4) << 0)
+
+#define UART_BUILD_REVISION(x, y)	(((x) << 8) | (y))
+
+#define OMAP_UART_REV_46 0x0406
+#define OMAP_UART_REV_52 0x0502
+#define OMAP_UART_REV_63 0x0603
+
+/* Interrupt Enable Register 2 */
+#define UART_OMAP_IER2			0x1B
+#define UART_OMAP_IER2_RHR_IT_DIS	BIT(2)
+
+/* Mode Definition Register 3 */
+#define UART_OMAP_MDR3			0x20
+#define UART_OMAP_MDR3_DIR_POL		BIT(3)
+#define UART_OMAP_MDR3_DIR_EN		BIT(4)
+
+/* Enhanced features register 2 */
+#define UART_OMAP_EFR2			0x23
+#define UART_OMAP_EFR2_TIMEOUT_BEHAVE	BIT(6)
+
+/* RX FIFO occupancy indicator */
+#define UART_OMAP_RX_LVL		0x19
+
+struct omap8250_priv {
+	void __iomem *membase;
+	int line;
+	u8 habit;
+	u8 mdr1;
+	u8 mdr3;
+	u8 efr;
+	u8 scr;
+	u8 wer;
+	u8 xon;
+	u8 xoff;
+	u8 delayed_restore;
+	u16 quot;
+
+	u8 tx_trigger;
+	u8 rx_trigger;
+	bool is_suspending;
+	int wakeirq;
+	int wakeups_enabled;
+	u32 latency;
+	u32 calc_latency;
+	struct pm_qos_request pm_qos_request;
+	struct work_struct qos_work;
+	struct uart_8250_dma omap8250_dma;
+	spinlock_t rx_dma_lock;
+	bool rx_dma_broken;
+	bool throttled;
+};
+
+struct omap8250_dma_params {
+	u32 rx_size;
+	u8 rx_trigger;
+	u8 tx_trigger;
+};
+
+struct omap8250_platdata {
+	struct omap8250_dma_params *dma_params;
+	u8 habit;
+};
+
+#ifdef CONFIG_SERIAL_8250_DMA
+static void omap_8250_rx_dma_flush(struct uart_8250_port *p);
+#else
+static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { }
+#endif
+
+static u32 uart_read(struct omap8250_priv *priv, u32 reg)
+{
+	return readl(priv->membase + (reg << OMAP_UART_REGSHIFT));
+}
+
+/*
+ * Called on runtime PM resume path from omap8250_restore_regs(), and
+ * omap8250_set_mctrl().
+ */
+static void __omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	struct omap8250_priv *priv = up->port.private_data;
+	u8 lcr;
+
+	serial8250_do_set_mctrl(port, mctrl);
+
+	if (!mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS)) {
+		/*
+		 * Turn off autoRTS if RTS is lowered and restore autoRTS
+		 * setting if RTS is raised
+		 */
+		lcr = serial_in(up, UART_LCR);
+		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+		if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
+			priv->efr |= UART_EFR_RTS;
+		else
+			priv->efr &= ~UART_EFR_RTS;
+		serial_out(up, UART_EFR, priv->efr);
+		serial_out(up, UART_LCR, lcr);
+	}
+}
+
+static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	int err;
+
+	err = pm_runtime_resume_and_get(port->dev);
+	if (err)
+		return;
+
+	__omap8250_set_mctrl(port, mctrl);
+
+	pm_runtime_mark_last_busy(port->dev);
+	pm_runtime_put_autosuspend(port->dev);
+}
+
+/*
+ * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460)
+ * The access to uart register after MDR1 Access
+ * causes UART to corrupt data.
+ *
+ * Need a delay =
+ * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
+ * give 10 times as much
+ */
+static void omap_8250_mdr1_errataset(struct uart_8250_port *up,
+				     struct omap8250_priv *priv)
+{
+	serial_out(up, UART_OMAP_MDR1, priv->mdr1);
+	udelay(2);
+	serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT |
+			UART_FCR_CLEAR_RCVR);
+}
+
+static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud,
+				  struct omap8250_priv *priv)
+{
+	unsigned int uartclk = port->uartclk;
+	unsigned int div_13, div_16;
+	unsigned int abs_d13, abs_d16;
+
+	/*
+	 * Old custom speed handling.
+	 */
+	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) {
+		priv->quot = port->custom_divisor & UART_DIV_MAX;
+		/*
+		 * I assume that nobody is using this. But hey, if somebody
+		 * would like to specify the divisor _and_ the mode then the
+		 * driver is ready and waiting for it.
+		 */
+		if (port->custom_divisor & (1 << 16))
+			priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
+		else
+			priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
+		return;
+	}
+	div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud);
+	div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud);
+
+	if (!div_13)
+		div_13 = 1;
+	if (!div_16)
+		div_16 = 1;
+
+	abs_d13 = abs(baud - uartclk / 13 / div_13);
+	abs_d16 = abs(baud - uartclk / 16 / div_16);
+
+	if (abs_d13 >= abs_d16) {
+		priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
+		priv->quot = div_16;
+	} else {
+		priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
+		priv->quot = div_13;
+	}
+}
+
+static void omap8250_update_scr(struct uart_8250_port *up,
+				struct omap8250_priv *priv)
+{
+	u8 old_scr;
+
+	old_scr = serial_in(up, UART_OMAP_SCR);
+	if (old_scr == priv->scr)
+		return;
+
+	/*
+	 * The manual recommends not to enable the DMA mode selector in the SCR
+	 * (instead of the FCR) register _and_ selecting the DMA mode as one
+	 * register write because this may lead to malfunction.
+	 */
+	if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK)
+		serial_out(up, UART_OMAP_SCR,
+			   priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK);
+	serial_out(up, UART_OMAP_SCR, priv->scr);
+}
+
+static void omap8250_update_mdr1(struct uart_8250_port *up,
+				 struct omap8250_priv *priv)
+{
+	if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS)
+		omap_8250_mdr1_errataset(up, priv);
+	else
+		serial_out(up, UART_OMAP_MDR1, priv->mdr1);
+}
+
+static void omap8250_restore_regs(struct uart_8250_port *up)
+{
+	struct omap8250_priv *priv = up->port.private_data;
+	struct uart_8250_dma	*dma = up->dma;
+	u8 mcr = serial8250_in_MCR(up);
+
+	/* Port locked to synchronize UART_IER access against the console. */
+	lockdep_assert_held_once(&up->port.lock);
+
+	if (dma && dma->tx_running) {
+		/*
+		 * TCSANOW requests the change to occur immediately however if
+		 * we have a TX-DMA operation in progress then it has been
+		 * observed that it might stall and never complete. Therefore we
+		 * delay DMA completes to prevent this hang from happen.
+		 */
+		priv->delayed_restore = 1;
+		return;
+	}
+
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+	serial_out(up, UART_EFR, UART_EFR_ECB);
+
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
+	serial8250_out_MCR(up, mcr | UART_MCR_TCRTLR);
+	serial_out(up, UART_FCR, up->fcr);
+
+	omap8250_update_scr(up, priv);
+
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+
+	serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) |
+			OMAP_UART_TCR_HALT(52));
+	serial_out(up, UART_TI752_TLR,
+		   TRIGGER_TLR_MASK(priv->tx_trigger) << UART_TI752_TLR_TX |
+		   TRIGGER_TLR_MASK(priv->rx_trigger) << UART_TI752_TLR_RX);
+
+	serial_out(up, UART_LCR, 0);
+
+	/* drop TCR + TLR access, we setup XON/XOFF later */
+	serial8250_out_MCR(up, mcr);
+
+	serial_out(up, UART_IER, up->ier);
+
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+	serial_dl_write(up, priv->quot);
+
+	serial_out(up, UART_EFR, priv->efr);
+
+	/* Configure flow control */
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+	serial_out(up, UART_XON1, priv->xon);
+	serial_out(up, UART_XOFF1, priv->xoff);
+
+	serial_out(up, UART_LCR, up->lcr);
+
+	omap8250_update_mdr1(up, priv);
+
+	__omap8250_set_mctrl(&up->port, up->port.mctrl);
+
+	serial_out(up, UART_OMAP_MDR3, priv->mdr3);
+
+	if (up->port.rs485.flags & SER_RS485_ENABLED &&
+	    up->port.rs485_config == serial8250_em485_config)
+		serial8250_em485_stop_tx(up);
+}
+
+/*
+ * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have
+ * some differences in how we want to handle flow control.
+ */
+static void omap_8250_set_termios(struct uart_port *port,
+				  struct ktermios *termios,
+				  const struct ktermios *old)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	struct omap8250_priv *priv = up->port.private_data;
+	unsigned char cval = 0;
+	unsigned int baud;
+
+	cval = UART_LCR_WLEN(tty_get_char_size(termios->c_cflag));
+
+	if (termios->c_cflag & CSTOPB)
+		cval |= UART_LCR_STOP;
+	if (termios->c_cflag & PARENB)
+		cval |= UART_LCR_PARITY;
+	if (!(termios->c_cflag & PARODD))
+		cval |= UART_LCR_EPAR;
+	if (termios->c_cflag & CMSPAR)
+		cval |= UART_LCR_SPAR;
+
+	/*
+	 * Ask the core to calculate the divisor for us.
+	 */
+	baud = uart_get_baud_rate(port, termios, old,
+				  port->uartclk / 16 / UART_DIV_MAX,
+				  port->uartclk / 13);
+	omap_8250_get_divisor(port, baud, priv);
+
+	/*
+	 * Ok, we're now changing the port state. Do it with
+	 * interrupts disabled.
+	 */
+	pm_runtime_get_sync(port->dev);
+	spin_lock_irq(&port->lock);
+
+	/*
+	 * Update the per-port timeout.
+	 */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
+	if (termios->c_iflag & INPCK)
+		up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
+	if (termios->c_iflag & (IGNBRK | PARMRK))
+		up->port.read_status_mask |= UART_LSR_BI;
+
+	/*
+	 * Characters to ignore
+	 */
+	up->port.ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
+	if (termios->c_iflag & IGNBRK) {
+		up->port.ignore_status_mask |= UART_LSR_BI;
+		/*
+		 * If we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			up->port.ignore_status_mask |= UART_LSR_OE;
+	}
+
+	/*
+	 * ignore all characters if CREAD is not set
+	 */
+	if ((termios->c_cflag & CREAD) == 0)
+		up->port.ignore_status_mask |= UART_LSR_DR;
+
+	/*
+	 * Modem status interrupts
+	 */
+	up->ier &= ~UART_IER_MSI;
+	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
+		up->ier |= UART_IER_MSI;
+
+	up->lcr = cval;
+	/* Up to here it was mostly serial8250_do_set_termios() */
+
+	/*
+	 * We enable TRIG_GRANU for RX and TX and additionally we set
+	 * SCR_TX_EMPTY bit. The result is the following:
+	 * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt.
+	 * - less than RX_TRIGGER number of bytes will also cause an interrupt
+	 *   once the UART decides that there no new bytes arriving.
+	 * - Once THRE is enabled, the interrupt will be fired once the FIFO is
+	 *   empty - the trigger level is ignored here.
+	 *
+	 * Once DMA is enabled:
+	 * - UART will assert the TX DMA line once there is room for TX_TRIGGER
+	 *   bytes in the TX FIFO. On each assert the DMA engine will move
+	 *   TX_TRIGGER bytes into the FIFO.
+	 * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in
+	 *   the FIFO and move RX_TRIGGER bytes.
+	 * This is because threshold and trigger values are the same.
+	 */
+	up->fcr = UART_FCR_ENABLE_FIFO;
+	up->fcr |= TRIGGER_FCR_MASK(priv->tx_trigger) << OMAP_UART_FCR_TX_TRIG;
+	up->fcr |= TRIGGER_FCR_MASK(priv->rx_trigger) << OMAP_UART_FCR_RX_TRIG;
+
+	priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY |
+		OMAP_UART_SCR_TX_TRIG_GRANU1_MASK;
+
+	if (up->dma)
+		priv->scr |= OMAP_UART_SCR_DMAMODE_1 |
+			OMAP_UART_SCR_DMAMODE_CTL;
+
+	priv->xon = termios->c_cc[VSTART];
+	priv->xoff = termios->c_cc[VSTOP];
+
+	priv->efr = 0;
+	up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
+
+	if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW &&
+	    !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS) &&
+	    !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_CTS)) {
+		/* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */
+		up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
+		priv->efr |= UART_EFR_CTS;
+	} else	if (up->port.flags & UPF_SOFT_FLOW) {
+		/*
+		 * OMAP rx s/w flow control is borked; the transmitter remains
+		 * stuck off even if rx flow control is subsequently disabled
+		 */
+
+		/*
+		 * IXOFF Flag:
+		 * Enable XON/XOFF flow control on output.
+		 * Transmit XON1, XOFF1
+		 */
+		if (termios->c_iflag & IXOFF) {
+			up->port.status |= UPSTAT_AUTOXOFF;
+			priv->efr |= OMAP_UART_SW_TX;
+		}
+	}
+	omap8250_restore_regs(up);
+
+	spin_unlock_irq(&up->port.lock);
+	pm_runtime_mark_last_busy(port->dev);
+	pm_runtime_put_autosuspend(port->dev);
+
+	/* calculate wakeup latency constraint */
+	priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud;
+	priv->latency = priv->calc_latency;
+
+	schedule_work(&priv->qos_work);
+
+	/* Don't rewrite B0 */
+	if (tty_termios_baud_rate(termios))
+		tty_termios_encode_baud_rate(termios, baud, baud);
+}
+
+/* same as 8250 except that we may have extra flow bits set in EFR */
+static void omap_8250_pm(struct uart_port *port, unsigned int state,
+			 unsigned int oldstate)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	u8 efr;
+
+	pm_runtime_get_sync(port->dev);
+
+	/* Synchronize UART_IER access against the console. */
+	spin_lock_irq(&port->lock);
+
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+	efr = serial_in(up, UART_EFR);
+	serial_out(up, UART_EFR, efr | UART_EFR_ECB);
+	serial_out(up, UART_LCR, 0);
+
+	serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+	serial_out(up, UART_EFR, efr);
+	serial_out(up, UART_LCR, 0);
+
+	spin_unlock_irq(&port->lock);
+
+	pm_runtime_mark_last_busy(port->dev);
+	pm_runtime_put_autosuspend(port->dev);
+}
+
+static void omap_serial_fill_features_erratas(struct uart_8250_port *up,
+					      struct omap8250_priv *priv)
+{
+	static const struct soc_device_attribute k3_soc_devices[] = {
+		{ .family = "AM65X",  },
+		{ .family = "J721E", .revision = "SR1.0" },
+		{ /* sentinel */ }
+	};
+	u32 mvr, scheme;
+	u16 revision, major, minor;
+
+	mvr = uart_read(priv, UART_OMAP_MVER);
+
+	/* Check revision register scheme */
+	scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT;
+
+	switch (scheme) {
+	case 0: /* Legacy Scheme: OMAP2/3 */
+		/* MINOR_REV[0:4], MAJOR_REV[4:7] */
+		major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >>
+			OMAP_UART_LEGACY_MVR_MAJ_SHIFT;
+		minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK);
+		break;
+	case 1:
+		/* New Scheme: OMAP4+ */
+		/* MINOR_REV[0:5], MAJOR_REV[8:10] */
+		major = (mvr & OMAP_UART_MVR_MAJ_MASK) >>
+			OMAP_UART_MVR_MAJ_SHIFT;
+		minor = (mvr & OMAP_UART_MVR_MIN_MASK);
+		break;
+	default:
+		dev_warn(up->port.dev,
+			 "Unknown revision, defaulting to highest\n");
+		/* highest possible revision */
+		major = 0xff;
+		minor = 0xff;
+	}
+	/* normalize revision for the driver */
+	revision = UART_BUILD_REVISION(major, minor);
+
+	switch (revision) {
+	case OMAP_UART_REV_46:
+		priv->habit |= UART_ERRATA_i202_MDR1_ACCESS;
+		break;
+	case OMAP_UART_REV_52:
+		priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
+				OMAP_UART_WER_HAS_TX_WAKEUP;
+		break;
+	case OMAP_UART_REV_63:
+		priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
+			OMAP_UART_WER_HAS_TX_WAKEUP;
+		break;
+	default:
+		break;
+	}
+
+	/*
+	 * AM65x SR1.0, AM65x SR2.0 and J721e SR1.0 don't
+	 * don't have RHR_IT_DIS bit in IER2 register. So drop to flag
+	 * to enable errata workaround.
+	 */
+	if (soc_device_match(k3_soc_devices))
+		priv->habit &= ~UART_HAS_RHR_IT_DIS;
+}
+
+static void omap8250_uart_qos_work(struct work_struct *work)
+{
+	struct omap8250_priv *priv;
+
+	priv = container_of(work, struct omap8250_priv, qos_work);
+	cpu_latency_qos_update_request(&priv->pm_qos_request, priv->latency);
+}
+
+#ifdef CONFIG_SERIAL_8250_DMA
+static int omap_8250_dma_handle_irq(struct uart_port *port);
+#endif
+
+static irqreturn_t omap8250_irq(int irq, void *dev_id)
+{
+	struct omap8250_priv *priv = dev_id;
+	struct uart_8250_port *up = serial8250_get_port(priv->line);
+	struct uart_port *port = &up->port;
+	unsigned int iir, lsr;
+	int ret;
+
+#ifdef CONFIG_SERIAL_8250_DMA
+	if (up->dma) {
+		ret = omap_8250_dma_handle_irq(port);
+		return IRQ_RETVAL(ret);
+	}
+#endif
+
+	serial8250_rpm_get(up);
+	lsr = serial_port_in(port, UART_LSR);
+	iir = serial_port_in(port, UART_IIR);
+	ret = serial8250_handle_irq(port, iir);
+
+	/*
+	 * On K3 SoCs, it is observed that RX TIMEOUT is signalled after
+	 * FIFO has been drained, in which case a dummy read of RX FIFO
+	 * is required to clear RX TIMEOUT condition.
+	 */
+	if (priv->habit & UART_RX_TIMEOUT_QUIRK &&
+	    (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT &&
+	    serial_port_in(port, UART_OMAP_RX_LVL) == 0) {
+		serial_port_in(port, UART_RX);
+	}
+
+	/* Stop processing interrupts on input overrun */
+	if ((lsr & UART_LSR_OE) && up->overrun_backoff_time_ms > 0) {
+		unsigned long delay;
+
+		/* Synchronize UART_IER access against the console. */
+		spin_lock(&port->lock);
+		up->ier = port->serial_in(port, UART_IER);
+		if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) {
+			port->ops->stop_rx(port);
+		} else {
+			/* Keep restarting the timer until
+			 * the input overrun subsides.
+			 */
+			cancel_delayed_work(&up->overrun_backoff);
+		}
+		spin_unlock(&port->lock);
+
+		delay = msecs_to_jiffies(up->overrun_backoff_time_ms);
+		schedule_delayed_work(&up->overrun_backoff, delay);
+	}
+
+	serial8250_rpm_put(up);
+
+	return IRQ_RETVAL(ret);
+}
+
+static int omap_8250_startup(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	struct omap8250_priv *priv = port->private_data;
+	struct uart_8250_dma *dma = &priv->omap8250_dma;
+	int ret;
+
+	if (priv->wakeirq) {
+		ret = dev_pm_set_dedicated_wake_irq(port->dev, priv->wakeirq);
+		if (ret)
+			return ret;
+	}
+
+	pm_runtime_get_sync(port->dev);
+
+	serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+
+	serial_out(up, UART_LCR, UART_LCR_WLEN8);
+
+	up->lsr_saved_flags = 0;
+	up->msr_saved_flags = 0;
+
+	/* Disable DMA for console UART */
+	if (dma->fn && !uart_console(port)) {
+		up->dma = &priv->omap8250_dma;
+		ret = serial8250_request_dma(up);
+		if (ret) {
+			dev_warn_ratelimited(port->dev,
+					     "failed to request DMA\n");
+			up->dma = NULL;
+		}
+	} else {
+		up->dma = NULL;
+	}
+
+	/* Synchronize UART_IER access against the console. */
+	spin_lock_irq(&port->lock);
+	up->ier = UART_IER_RLSI | UART_IER_RDI;
+	serial_out(up, UART_IER, up->ier);
+	spin_unlock_irq(&port->lock);
+
+#ifdef CONFIG_PM
+	up->capabilities |= UART_CAP_RPM;
+#endif
+
+	/* Enable module level wake up */
+	priv->wer = OMAP_UART_WER_MOD_WKUP;
+	if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP)
+		priv->wer |= OMAP_UART_TX_WAKEUP_EN;
+	serial_out(up, UART_OMAP_WER, priv->wer);
+
+	if (up->dma && !(priv->habit & UART_HAS_EFR2)) {
+		spin_lock_irq(&port->lock);
+		up->dma->rx_dma(up);
+		spin_unlock_irq(&port->lock);
+	}
+
+	enable_irq(up->port.irq);
+
+	pm_runtime_mark_last_busy(port->dev);
+	pm_runtime_put_autosuspend(port->dev);
+	return 0;
+}
+
+static void omap_8250_shutdown(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	struct omap8250_priv *priv = port->private_data;
+
+	flush_work(&priv->qos_work);
+	if (up->dma)
+		omap_8250_rx_dma_flush(up);
+
+	pm_runtime_get_sync(port->dev);
+
+	serial_out(up, UART_OMAP_WER, 0);
+	if (priv->habit & UART_HAS_EFR2)
+		serial_out(up, UART_OMAP_EFR2, 0x0);
+
+	/* Synchronize UART_IER access against the console. */
+	spin_lock_irq(&port->lock);
+	up->ier = 0;
+	serial_out(up, UART_IER, 0);
+	spin_unlock_irq(&port->lock);
+	disable_irq_nosync(up->port.irq);
+	dev_pm_clear_wake_irq(port->dev);
+
+	serial8250_release_dma(up);
+	up->dma = NULL;
+
+	/*
+	 * Disable break condition and FIFOs
+	 */
+	if (up->lcr & UART_LCR_SBC)
+		serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC);
+	serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+
+	pm_runtime_mark_last_busy(port->dev);
+	pm_runtime_put_autosuspend(port->dev);
+}
+
+static void omap_8250_throttle(struct uart_port *port)
+{
+	struct omap8250_priv *priv = port->private_data;
+	unsigned long flags;
+
+	pm_runtime_get_sync(port->dev);
+
+	spin_lock_irqsave(&port->lock, flags);
+	port->ops->stop_rx(port);
+	priv->throttled = true;
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	pm_runtime_mark_last_busy(port->dev);
+	pm_runtime_put_autosuspend(port->dev);
+}
+
+static void omap_8250_unthrottle(struct uart_port *port)
+{
+	struct omap8250_priv *priv = port->private_data;
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned long flags;
+
+	pm_runtime_get_sync(port->dev);
+
+	/* Synchronize UART_IER access against the console. */
+	spin_lock_irqsave(&port->lock, flags);
+	priv->throttled = false;
+	if (up->dma)
+		up->dma->rx_dma(up);
+	up->ier |= UART_IER_RLSI | UART_IER_RDI;
+	port->read_status_mask |= UART_LSR_DR;
+	serial_out(up, UART_IER, up->ier);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	pm_runtime_mark_last_busy(port->dev);
+	pm_runtime_put_autosuspend(port->dev);
+}
+
+static int omap8250_rs485_config(struct uart_port *port,
+				 struct ktermios *termios,
+				 struct serial_rs485 *rs485)
+{
+	struct omap8250_priv *priv = port->private_data;
+	struct uart_8250_port *up = up_to_u8250p(port);
+	u32 fixed_delay_rts_before_send = 0;
+	u32 fixed_delay_rts_after_send = 0;
+	unsigned int baud;
+
+	/*
+	 * There is a fixed delay of 3 bit clock cycles after the TX shift
+	 * register is going empty to allow time for the stop bit to transition
+	 * through the transceiver before direction is changed to receive.
+	 *
+	 * Additionally there appears to be a 1 bit clock delay between writing
+	 * to the THR register and transmission of the start bit, per page 8783
+	 * of the AM65 TRM:  https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf
+	 */
+	if (priv->quot) {
+		if (priv->mdr1 == UART_OMAP_MDR1_16X_MODE)
+			baud = port->uartclk / (16 * priv->quot);
+		else
+			baud = port->uartclk / (13 * priv->quot);
+
+		fixed_delay_rts_after_send  = 3 * MSEC_PER_SEC / baud;
+		fixed_delay_rts_before_send = 1 * MSEC_PER_SEC / baud;
+	}
+
+	/*
+	 * Fall back to RS485 software emulation if the UART is missing
+	 * hardware support, if the device tree specifies an mctrl_gpio
+	 * (indicates that RTS is unavailable due to a pinmux conflict)
+	 * or if the requested delays exceed the fixed hardware delays.
+	 */
+	if (!(priv->habit & UART_HAS_NATIVE_RS485) ||
+	    mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS) ||
+	    rs485->delay_rts_after_send  > fixed_delay_rts_after_send ||
+	    rs485->delay_rts_before_send > fixed_delay_rts_before_send) {
+		priv->mdr3 &= ~UART_OMAP_MDR3_DIR_EN;
+		serial_out(up, UART_OMAP_MDR3, priv->mdr3);
+
+		port->rs485_config = serial8250_em485_config;
+		return serial8250_em485_config(port, termios, rs485);
+	}
+
+	rs485->delay_rts_after_send  = fixed_delay_rts_after_send;
+	rs485->delay_rts_before_send = fixed_delay_rts_before_send;
+
+	if (rs485->flags & SER_RS485_ENABLED)
+		priv->mdr3 |= UART_OMAP_MDR3_DIR_EN;
+	else
+		priv->mdr3 &= ~UART_OMAP_MDR3_DIR_EN;
+
+	/*
+	 * Retain same polarity semantics as RS485 software emulation,
+	 * i.e. SER_RS485_RTS_ON_SEND means driving RTS low on send.
+	 */
+	if (rs485->flags & SER_RS485_RTS_ON_SEND)
+		priv->mdr3 &= ~UART_OMAP_MDR3_DIR_POL;
+	else
+		priv->mdr3 |= UART_OMAP_MDR3_DIR_POL;
+
+	serial_out(up, UART_OMAP_MDR3, priv->mdr3);
+
+	return 0;
+}
+
+#ifdef CONFIG_SERIAL_8250_DMA
+static int omap_8250_rx_dma(struct uart_8250_port *p);
+
+/* Must be called while priv->rx_dma_lock is held */
+static void __dma_rx_do_complete(struct uart_8250_port *p)
+{
+	struct uart_8250_dma    *dma = p->dma;
+	struct tty_port         *tty_port = &p->port.state->port;
+	struct omap8250_priv	*priv = p->port.private_data;
+	struct dma_chan		*rxchan = dma->rxchan;
+	dma_cookie_t		cookie;
+	struct dma_tx_state     state;
+	int                     count;
+	int			ret;
+	u32			reg;
+
+	if (!dma->rx_running)
+		goto out;
+
+	cookie = dma->rx_cookie;
+	dma->rx_running = 0;
+
+	/* Re-enable RX FIFO interrupt now that transfer is complete */
+	if (priv->habit & UART_HAS_RHR_IT_DIS) {
+		reg = serial_in(p, UART_OMAP_IER2);
+		reg &= ~UART_OMAP_IER2_RHR_IT_DIS;
+		serial_out(p, UART_OMAP_IER2, reg);
+	}
+
+	dmaengine_tx_status(rxchan, cookie, &state);
+
+	count = dma->rx_size - state.residue + state.in_flight_bytes;
+	if (count < dma->rx_size) {
+		dmaengine_terminate_async(rxchan);
+
+		/*
+		 * Poll for teardown to complete which guarantees in
+		 * flight data is drained.
+		 */
+		if (state.in_flight_bytes) {
+			int poll_count = 25;
+
+			while (dmaengine_tx_status(rxchan, cookie, NULL) &&
+			       poll_count--)
+				cpu_relax();
+
+			if (poll_count == -1)
+				dev_err(p->port.dev, "teardown incomplete\n");
+		}
+	}
+	if (!count)
+		goto out;
+	ret = tty_insert_flip_string(tty_port, dma->rx_buf, count);
+
+	p->port.icount.rx += ret;
+	p->port.icount.buf_overrun += count - ret;
+out:
+
+	tty_flip_buffer_push(tty_port);
+}
+
+static void __dma_rx_complete(void *param)
+{
+	struct uart_8250_port *p = param;
+	struct omap8250_priv *priv = p->port.private_data;
+	struct uart_8250_dma *dma = p->dma;
+	struct dma_tx_state     state;
+	unsigned long flags;
+
+	/* Synchronize UART_IER access against the console. */
+	spin_lock_irqsave(&p->port.lock, flags);
+
+	/*
+	 * If the tx status is not DMA_COMPLETE, then this is a delayed
+	 * completion callback. A previous RX timeout flush would have
+	 * already pushed the data, so exit.
+	 */
+	if (dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state) !=
+			DMA_COMPLETE) {
+		spin_unlock_irqrestore(&p->port.lock, flags);
+		return;
+	}
+	__dma_rx_do_complete(p);
+	if (!priv->throttled) {
+		p->ier |= UART_IER_RLSI | UART_IER_RDI;
+		serial_out(p, UART_IER, p->ier);
+		if (!(priv->habit & UART_HAS_EFR2))
+			omap_8250_rx_dma(p);
+	}
+
+	spin_unlock_irqrestore(&p->port.lock, flags);
+}
+
+static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
+{
+	struct omap8250_priv	*priv = p->port.private_data;
+	struct uart_8250_dma	*dma = p->dma;
+	struct dma_tx_state     state;
+	unsigned long		flags;
+	int ret;
+
+	spin_lock_irqsave(&priv->rx_dma_lock, flags);
+
+	if (!dma->rx_running) {
+		spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
+		return;
+	}
+
+	ret = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
+	if (ret == DMA_IN_PROGRESS) {
+		ret = dmaengine_pause(dma->rxchan);
+		if (WARN_ON_ONCE(ret))
+			priv->rx_dma_broken = true;
+	}
+	__dma_rx_do_complete(p);
+	spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
+}
+
+static int omap_8250_rx_dma(struct uart_8250_port *p)
+{
+	struct omap8250_priv		*priv = p->port.private_data;
+	struct uart_8250_dma            *dma = p->dma;
+	int				err = 0;
+	struct dma_async_tx_descriptor  *desc;
+	unsigned long			flags;
+	u32				reg;
+
+	/* Port locked to synchronize UART_IER access against the console. */
+	lockdep_assert_held_once(&p->port.lock);
+
+	if (priv->rx_dma_broken)
+		return -EINVAL;
+
+	spin_lock_irqsave(&priv->rx_dma_lock, flags);
+
+	if (dma->rx_running) {
+		enum dma_status state;
+
+		state = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, NULL);
+		if (state == DMA_COMPLETE) {
+			/*
+			 * Disable RX interrupts to allow RX DMA completion
+			 * callback to run.
+			 */
+			p->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
+			serial_out(p, UART_IER, p->ier);
+		}
+		goto out;
+	}
+
+	desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
+					   dma->rx_size, DMA_DEV_TO_MEM,
+					   DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc) {
+		err = -EBUSY;
+		goto out;
+	}
+
+	dma->rx_running = 1;
+	desc->callback = __dma_rx_complete;
+	desc->callback_param = p;
+
+	dma->rx_cookie = dmaengine_submit(desc);
+
+	/*
+	 * Disable RX FIFO interrupt while RX DMA is enabled, else
+	 * spurious interrupt may be raised when data is in the RX FIFO
+	 * but is yet to be drained by DMA.
+	 */
+	if (priv->habit & UART_HAS_RHR_IT_DIS) {
+		reg = serial_in(p, UART_OMAP_IER2);
+		reg |= UART_OMAP_IER2_RHR_IT_DIS;
+		serial_out(p, UART_OMAP_IER2, reg);
+	}
+
+	dma_async_issue_pending(dma->rxchan);
+out:
+	spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
+	return err;
+}
+
+static int omap_8250_tx_dma(struct uart_8250_port *p);
+
+static void omap_8250_dma_tx_complete(void *param)
+{
+	struct uart_8250_port	*p = param;
+	struct uart_8250_dma	*dma = p->dma;
+	struct circ_buf		*xmit = &p->port.state->xmit;
+	unsigned long		flags;
+	bool			en_thri = false;
+	struct omap8250_priv	*priv = p->port.private_data;
+
+	dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
+				UART_XMIT_SIZE, DMA_TO_DEVICE);
+
+	spin_lock_irqsave(&p->port.lock, flags);
+
+	dma->tx_running = 0;
+
+	uart_xmit_advance(&p->port, dma->tx_size);
+
+	if (priv->delayed_restore) {
+		priv->delayed_restore = 0;
+		omap8250_restore_regs(p);
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(&p->port);
+
+	if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) {
+		int ret;
+
+		ret = omap_8250_tx_dma(p);
+		if (ret)
+			en_thri = true;
+	} else if (p->capabilities & UART_CAP_RPM) {
+		en_thri = true;
+	}
+
+	if (en_thri) {
+		dma->tx_err = 1;
+		serial8250_set_THRI(p);
+	}
+
+	spin_unlock_irqrestore(&p->port.lock, flags);
+}
+
+static int omap_8250_tx_dma(struct uart_8250_port *p)
+{
+	struct uart_8250_dma		*dma = p->dma;
+	struct omap8250_priv		*priv = p->port.private_data;
+	struct circ_buf			*xmit = &p->port.state->xmit;
+	struct dma_async_tx_descriptor	*desc;
+	unsigned int	skip_byte = 0;
+	int ret;
+
+	if (dma->tx_running)
+		return 0;
+	if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) {
+
+		/*
+		 * Even if no data, we need to return an error for the two cases
+		 * below so serial8250_tx_chars() is invoked and properly clears
+		 * THRI and/or runtime suspend.
+		 */
+		if (dma->tx_err || p->capabilities & UART_CAP_RPM) {
+			ret = -EBUSY;
+			goto err;
+		}
+		serial8250_clear_THRI(p);
+		return 0;
+	}
+
+	dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+	if (priv->habit & OMAP_DMA_TX_KICK) {
+		u8 tx_lvl;
+
+		/*
+		 * We need to put the first byte into the FIFO in order to start
+		 * the DMA transfer. For transfers smaller than four bytes we
+		 * don't bother doing DMA at all. It seem not matter if there
+		 * are still bytes in the FIFO from the last transfer (in case
+		 * we got here directly from omap_8250_dma_tx_complete()). Bytes
+		 * leaving the FIFO seem not to trigger the DMA transfer. It is
+		 * really the byte that we put into the FIFO.
+		 * If the FIFO is already full then we most likely got here from
+		 * omap_8250_dma_tx_complete(). And this means the DMA engine
+		 * just completed its work. We don't have to wait the complete
+		 * 86us at 115200,8n1 but around 60us (not to mention lower
+		 * baudrates). So in that case we take the interrupt and try
+		 * again with an empty FIFO.
+		 */
+		tx_lvl = serial_in(p, UART_OMAP_TX_LVL);
+		if (tx_lvl == p->tx_loadsz) {
+			ret = -EBUSY;
+			goto err;
+		}
+		if (dma->tx_size < 4) {
+			ret = -EINVAL;
+			goto err;
+		}
+		skip_byte = 1;
+	}
+
+	desc = dmaengine_prep_slave_single(dma->txchan,
+			dma->tx_addr + xmit->tail + skip_byte,
+			dma->tx_size - skip_byte, DMA_MEM_TO_DEV,
+			DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc) {
+		ret = -EBUSY;
+		goto err;
+	}
+
+	dma->tx_running = 1;
+
+	desc->callback = omap_8250_dma_tx_complete;
+	desc->callback_param = p;
+
+	dma->tx_cookie = dmaengine_submit(desc);
+
+	dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr,
+				   UART_XMIT_SIZE, DMA_TO_DEVICE);
+
+	dma_async_issue_pending(dma->txchan);
+	if (dma->tx_err)
+		dma->tx_err = 0;
+
+	serial8250_clear_THRI(p);
+	if (skip_byte)
+		serial_out(p, UART_TX, xmit->buf[xmit->tail]);
+	return 0;
+err:
+	dma->tx_err = 1;
+	return ret;
+}
+
+static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
+{
+	switch (iir & 0x3f) {
+	case UART_IIR_RLSI:
+	case UART_IIR_RX_TIMEOUT:
+	case UART_IIR_RDI:
+		omap_8250_rx_dma_flush(up);
+		return true;
+	}
+	return omap_8250_rx_dma(up);
+}
+
+static u16 omap_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir, u16 status)
+{
+	if ((status & (UART_LSR_DR | UART_LSR_BI)) &&
+	    (iir & UART_IIR_RDI)) {
+		if (handle_rx_dma(up, iir)) {
+			status = serial8250_rx_chars(up, status);
+			omap_8250_rx_dma(up);
+		}
+	}
+
+	return status;
+}
+
+static void am654_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir,
+				     u16 status)
+{
+	/* Port locked to synchronize UART_IER access against the console. */
+	lockdep_assert_held_once(&up->port.lock);
+
+	/*
+	 * Queue a new transfer if FIFO has data.
+	 */
+	if ((status & (UART_LSR_DR | UART_LSR_BI)) &&
+	    (up->ier & UART_IER_RDI)) {
+		omap_8250_rx_dma(up);
+		serial_out(up, UART_OMAP_EFR2, UART_OMAP_EFR2_TIMEOUT_BEHAVE);
+	} else if ((iir & 0x3f) == UART_IIR_RX_TIMEOUT) {
+		/*
+		 * Disable RX timeout, read IIR to clear
+		 * current timeout condition, clear EFR2 to
+		 * periodic timeouts, re-enable interrupts.
+		 */
+		up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
+		serial_out(up, UART_IER, up->ier);
+		omap_8250_rx_dma_flush(up);
+		serial_in(up, UART_IIR);
+		serial_out(up, UART_OMAP_EFR2, 0x0);
+		up->ier |= UART_IER_RLSI | UART_IER_RDI;
+		serial_out(up, UART_IER, up->ier);
+	}
+}
+
+/*
+ * This is mostly serial8250_handle_irq(). We have a slightly different DMA
+ * hoook for RX/TX and need different logic for them in the ISR. Therefore we
+ * use the default routine in the non-DMA case and this one for with DMA.
+ */
+static int omap_8250_dma_handle_irq(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	struct omap8250_priv *priv = up->port.private_data;
+	u16 status;
+	u8 iir;
+
+	serial8250_rpm_get(up);
+
+	iir = serial_port_in(port, UART_IIR);
+	if (iir & UART_IIR_NO_INT) {
+		serial8250_rpm_put(up);
+		return IRQ_HANDLED;
+	}
+
+	spin_lock(&port->lock);
+
+	status = serial_port_in(port, UART_LSR);
+
+	if ((iir & 0x3f) != UART_IIR_THRI) {
+		if (priv->habit & UART_HAS_EFR2)
+			am654_8250_handle_rx_dma(up, iir, status);
+		else
+			status = omap_8250_handle_rx_dma(up, iir, status);
+	}
+
+	serial8250_modem_status(up);
+	if (status & UART_LSR_THRE && up->dma->tx_err) {
+		if (uart_tx_stopped(&up->port) ||
+		    uart_circ_empty(&up->port.state->xmit)) {
+			up->dma->tx_err = 0;
+			serial8250_tx_chars(up);
+		} else  {
+			/*
+			 * try again due to an earlier failer which
+			 * might have been resolved by now.
+			 */
+			if (omap_8250_tx_dma(up))
+				serial8250_tx_chars(up);
+		}
+	}
+
+	uart_unlock_and_check_sysrq(port);
+
+	serial8250_rpm_put(up);
+	return 1;
+}
+
+static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
+{
+	return false;
+}
+
+#else
+
+static inline int omap_8250_rx_dma(struct uart_8250_port *p)
+{
+	return -EINVAL;
+}
+#endif
+
+static int omap8250_no_handle_irq(struct uart_port *port)
+{
+	/* IRQ has not been requested but handling irq? */
+	WARN_ONCE(1, "Unexpected irq handling before port startup\n");
+	return 0;
+}
+
+static struct omap8250_dma_params am654_dma = {
+	.rx_size = SZ_2K,
+	.rx_trigger = 1,
+	.tx_trigger = TX_TRIGGER,
+};
+
+static struct omap8250_dma_params am33xx_dma = {
+	.rx_size = RX_TRIGGER,
+	.rx_trigger = RX_TRIGGER,
+	.tx_trigger = TX_TRIGGER,
+};
+
+static struct omap8250_platdata am654_platdata = {
+	.dma_params	= &am654_dma,
+	.habit		= UART_HAS_EFR2 | UART_HAS_RHR_IT_DIS |
+			  UART_RX_TIMEOUT_QUIRK | UART_HAS_NATIVE_RS485,
+};
+
+static struct omap8250_platdata am33xx_platdata = {
+	.dma_params	= &am33xx_dma,
+	.habit		= OMAP_DMA_TX_KICK | UART_ERRATA_CLOCK_DISABLE,
+};
+
+static struct omap8250_platdata omap4_platdata = {
+	.dma_params	= &am33xx_dma,
+	.habit		= UART_ERRATA_CLOCK_DISABLE,
+};
+
+static const struct of_device_id omap8250_dt_ids[] = {
+	{ .compatible = "ti,am654-uart", .data = &am654_platdata, },
+	{ .compatible = "ti,omap2-uart" },
+	{ .compatible = "ti,omap3-uart" },
+	{ .compatible = "ti,omap4-uart", .data = &omap4_platdata, },
+	{ .compatible = "ti,am3352-uart", .data = &am33xx_platdata, },
+	{ .compatible = "ti,am4372-uart", .data = &am33xx_platdata, },
+	{ .compatible = "ti,dra742-uart", .data = &omap4_platdata, },
+	{},
+};
+MODULE_DEVICE_TABLE(of, omap8250_dt_ids);
+
+static int omap8250_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct omap8250_priv *priv;
+	const struct omap8250_platdata *pdata;
+	struct uart_8250_port up;
+	struct resource *regs;
+	void __iomem *membase;
+	int irq, ret;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs) {
+		dev_err(&pdev->dev, "missing registers\n");
+		return -EINVAL;
+	}
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	membase = devm_ioremap(&pdev->dev, regs->start,
+				       resource_size(regs));
+	if (!membase)
+		return -ENODEV;
+
+	memset(&up, 0, sizeof(up));
+	up.port.dev = &pdev->dev;
+	up.port.mapbase = regs->start;
+	up.port.membase = membase;
+	up.port.irq = irq;
+	/*
+	 * It claims to be 16C750 compatible however it is a little different.
+	 * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to
+	 * have) is enabled via EFR instead of MCR. The type is set here 8250
+	 * just to get things going. UNKNOWN does not work for a few reasons and
+	 * we don't need our own type since we don't use 8250's set_termios()
+	 * or pm callback.
+	 */
+	up.port.type = PORT_8250;
+	up.port.iotype = UPIO_MEM;
+	up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW |
+		UPF_HARD_FLOW;
+	up.port.private_data = priv;
+
+	up.port.regshift = OMAP_UART_REGSHIFT;
+	up.port.fifosize = 64;
+	up.tx_loadsz = 64;
+	up.capabilities = UART_CAP_FIFO;
+#ifdef CONFIG_PM
+	/*
+	 * Runtime PM is mostly transparent. However to do it right we need to a
+	 * TX empty interrupt before we can put the device to auto idle. So if
+	 * PM is not enabled we don't add that flag and can spare that one extra
+	 * interrupt in the TX path.
+	 */
+	up.capabilities |= UART_CAP_RPM;
+#endif
+	up.port.set_termios = omap_8250_set_termios;
+	up.port.set_mctrl = omap8250_set_mctrl;
+	up.port.pm = omap_8250_pm;
+	up.port.startup = omap_8250_startup;
+	up.port.shutdown = omap_8250_shutdown;
+	up.port.throttle = omap_8250_throttle;
+	up.port.unthrottle = omap_8250_unthrottle;
+	up.port.rs485_config = omap8250_rs485_config;
+	/* same rs485_supported for software emulation and native RS485 */
+	up.port.rs485_supported = serial8250_em485_supported;
+	up.rs485_start_tx = serial8250_em485_start_tx;
+	up.rs485_stop_tx = serial8250_em485_stop_tx;
+	up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
+
+	ret = of_alias_get_id(np, "serial");
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to get alias\n");
+		return ret;
+	}
+	up.port.line = ret;
+
+	if (of_property_read_u32(np, "clock-frequency", &up.port.uartclk)) {
+		struct clk *clk;
+
+		clk = devm_clk_get(&pdev->dev, NULL);
+		if (IS_ERR(clk)) {
+			if (PTR_ERR(clk) == -EPROBE_DEFER)
+				return -EPROBE_DEFER;
+		} else {
+			up.port.uartclk = clk_get_rate(clk);
+		}
+	}
+
+	if (of_property_read_u32(np, "overrun-throttle-ms",
+				 &up.overrun_backoff_time_ms) != 0)
+		up.overrun_backoff_time_ms = 0;
+
+	pdata = of_device_get_match_data(&pdev->dev);
+	if (pdata)
+		priv->habit |= pdata->habit;
+
+	if (!up.port.uartclk) {
+		up.port.uartclk = DEFAULT_CLK_SPEED;
+		dev_warn(&pdev->dev,
+			 "No clock speed specified: using default: %d\n",
+			 DEFAULT_CLK_SPEED);
+	}
+
+	priv->membase = membase;
+	priv->line = -ENODEV;
+	priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
+	priv->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
+	cpu_latency_qos_add_request(&priv->pm_qos_request, priv->latency);
+	INIT_WORK(&priv->qos_work, omap8250_uart_qos_work);
+
+	spin_lock_init(&priv->rx_dma_lock);
+
+	platform_set_drvdata(pdev, priv);
+
+	device_init_wakeup(&pdev->dev, true);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_use_autosuspend(&pdev->dev);
+
+	/*
+	 * Disable runtime PM until autosuspend delay unless specifically
+	 * enabled by the user via sysfs. This is the historic way to
+	 * prevent an unsafe default policy with lossy characters on wake-up.
+	 * For serdev devices this is not needed, the policy can be managed by
+	 * the serdev driver.
+	 */
+	if (!of_get_available_child_count(pdev->dev.of_node))
+		pm_runtime_set_autosuspend_delay(&pdev->dev, -1);
+
+	pm_runtime_irq_safe(&pdev->dev);
+
+	pm_runtime_get_sync(&pdev->dev);
+
+	omap_serial_fill_features_erratas(&up, priv);
+	up.port.handle_irq = omap8250_no_handle_irq;
+	priv->rx_trigger = RX_TRIGGER;
+	priv->tx_trigger = TX_TRIGGER;
+#ifdef CONFIG_SERIAL_8250_DMA
+	/*
+	 * Oh DMA support. If there are no DMA properties in the DT then
+	 * we will fall back to a generic DMA channel which does not
+	 * really work here. To ensure that we do not get a generic DMA
+	 * channel assigned, we have the the_no_dma_filter_fn() here.
+	 * To avoid "failed to request DMA" messages we check for DMA
+	 * properties in DT.
+	 */
+	ret = of_property_count_strings(np, "dma-names");
+	if (ret == 2) {
+		struct omap8250_dma_params *dma_params = NULL;
+		struct uart_8250_dma *dma = &priv->omap8250_dma;
+
+		dma->fn = the_no_dma_filter_fn;
+		dma->tx_dma = omap_8250_tx_dma;
+		dma->rx_dma = omap_8250_rx_dma;
+		if (pdata)
+			dma_params = pdata->dma_params;
+
+		if (dma_params) {
+			dma->rx_size = dma_params->rx_size;
+			dma->rxconf.src_maxburst = dma_params->rx_trigger;
+			dma->txconf.dst_maxburst = dma_params->tx_trigger;
+			priv->rx_trigger = dma_params->rx_trigger;
+			priv->tx_trigger = dma_params->tx_trigger;
+		} else {
+			dma->rx_size = RX_TRIGGER;
+			dma->rxconf.src_maxburst = RX_TRIGGER;
+			dma->txconf.dst_maxburst = TX_TRIGGER;
+		}
+	}
+#endif
+
+	irq_set_status_flags(irq, IRQ_NOAUTOEN);
+	ret = devm_request_irq(&pdev->dev, irq, omap8250_irq, 0,
+			       dev_name(&pdev->dev), priv);
+	if (ret < 0)
+		return ret;
+
+	priv->wakeirq = irq_of_parse_and_map(np, 1);
+
+	ret = serial8250_register_8250_port(&up);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "unable to register 8250 port\n");
+		goto err;
+	}
+	priv->line = ret;
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
+	return 0;
+err:
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
+	flush_work(&priv->qos_work);
+	pm_runtime_disable(&pdev->dev);
+	cpu_latency_qos_remove_request(&priv->pm_qos_request);
+	return ret;
+}
+
+static int omap8250_remove(struct platform_device *pdev)
+{
+	struct omap8250_priv *priv = platform_get_drvdata(pdev);
+	struct uart_8250_port *up;
+	int err;
+
+	err = pm_runtime_resume_and_get(&pdev->dev);
+	if (err)
+		dev_err(&pdev->dev, "Failed to resume hardware\n");
+
+	up = serial8250_get_port(priv->line);
+	omap_8250_shutdown(&up->port);
+	serial8250_unregister_port(priv->line);
+	priv->line = -ENODEV;
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
+	flush_work(&priv->qos_work);
+	pm_runtime_disable(&pdev->dev);
+	cpu_latency_qos_remove_request(&priv->pm_qos_request);
+	device_init_wakeup(&pdev->dev, false);
+	return 0;
+}
+
+static int omap8250_prepare(struct device *dev)
+{
+	struct omap8250_priv *priv = dev_get_drvdata(dev);
+
+	if (!priv)
+		return 0;
+	priv->is_suspending = true;
+	return 0;
+}
+
+static void omap8250_complete(struct device *dev)
+{
+	struct omap8250_priv *priv = dev_get_drvdata(dev);
+
+	if (!priv)
+		return;
+	priv->is_suspending = false;
+}
+
+static int omap8250_suspend(struct device *dev)
+{
+	struct omap8250_priv *priv = dev_get_drvdata(dev);
+	struct uart_8250_port *up = serial8250_get_port(priv->line);
+	int err = 0;
+
+	serial8250_suspend_port(priv->line);
+
+	err = pm_runtime_resume_and_get(dev);
+	if (err)
+		return err;
+	if (!device_may_wakeup(dev))
+		priv->wer = 0;
+	serial_out(up, UART_OMAP_WER, priv->wer);
+	if (uart_console(&up->port) && console_suspend_enabled)
+		err = pm_runtime_force_suspend(dev);
+	flush_work(&priv->qos_work);
+
+	return err;
+}
+
+static int omap8250_resume(struct device *dev)
+{
+	struct omap8250_priv *priv = dev_get_drvdata(dev);
+	struct uart_8250_port *up = serial8250_get_port(priv->line);
+	int err;
+
+	if (uart_console(&up->port) && console_suspend_enabled) {
+		err = pm_runtime_force_resume(dev);
+		if (err)
+			return err;
+	}
+
+	serial8250_resume_port(priv->line);
+	/* Paired with pm_runtime_resume_and_get() in omap8250_suspend() */
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
+	return 0;
+}
+
+static int omap8250_lost_context(struct uart_8250_port *up)
+{
+	u32 val;
+
+	val = serial_in(up, UART_OMAP_SCR);
+	/*
+	 * If we lose context, then SCR is set to its reset value of zero.
+	 * After set_termios() we set bit 3 of SCR (TX_EMPTY_CTL_IT) to 1,
+	 * among other bits, to never set the register back to zero again.
+	 */
+	if (!val)
+		return 1;
+	return 0;
+}
+
+static void uart_write(struct omap8250_priv *priv, u32 reg, u32 val)
+{
+	writel(val, priv->membase + (reg << OMAP_UART_REGSHIFT));
+}
+
+/* TODO: in future, this should happen via API in drivers/reset/ */
+static int omap8250_soft_reset(struct device *dev)
+{
+	struct omap8250_priv *priv = dev_get_drvdata(dev);
+	int timeout = 100;
+	int sysc;
+	int syss;
+
+	/*
+	 * At least on omap4, unused uarts may not idle after reset without
+	 * a basic scr dma configuration even with no dma in use. The
+	 * module clkctrl status bits will be 1 instead of 3 blocking idle
+	 * for the whole clockdomain. The softreset below will clear scr,
+	 * and we restore it on resume so this is safe to do on all SoCs
+	 * needing omap8250_soft_reset() quirk. Do it in two writes as
+	 * recommended in the comment for omap8250_update_scr().
+	 */
+	uart_write(priv, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1);
+	uart_write(priv, UART_OMAP_SCR,
+		   OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL);
+
+	sysc = uart_read(priv, UART_OMAP_SYSC);
+
+	/* softreset the UART */
+	sysc |= OMAP_UART_SYSC_SOFTRESET;
+	uart_write(priv, UART_OMAP_SYSC, sysc);
+
+	/* By experiments, 1us enough for reset complete on AM335x */
+	do {
+		udelay(1);
+		syss = uart_read(priv, UART_OMAP_SYSS);
+	} while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE));
+
+	if (!timeout) {
+		dev_err(dev, "timed out waiting for reset done\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int omap8250_runtime_suspend(struct device *dev)
+{
+	struct omap8250_priv *priv = dev_get_drvdata(dev);
+	struct uart_8250_port *up = NULL;
+
+	if (priv->line >= 0)
+		up = serial8250_get_port(priv->line);
+
+	if (priv->habit & UART_ERRATA_CLOCK_DISABLE) {
+		int ret;
+
+		ret = omap8250_soft_reset(dev);
+		if (ret)
+			return ret;
+
+		if (up) {
+			/* Restore to UART mode after reset (for wakeup) */
+			omap8250_update_mdr1(up, priv);
+			/* Restore wakeup enable register */
+			serial_out(up, UART_OMAP_WER, priv->wer);
+		}
+	}
+
+	if (up && up->dma && up->dma->rxchan)
+		omap_8250_rx_dma_flush(up);
+
+	priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
+	schedule_work(&priv->qos_work);
+
+	return 0;
+}
+
+static int omap8250_runtime_resume(struct device *dev)
+{
+	struct omap8250_priv *priv = dev_get_drvdata(dev);
+	struct uart_8250_port *up = NULL;
+
+	if (priv->line >= 0)
+		up = serial8250_get_port(priv->line);
+
+	if (up && omap8250_lost_context(up)) {
+		spin_lock_irq(&up->port.lock);
+		omap8250_restore_regs(up);
+		spin_unlock_irq(&up->port.lock);
+	}
+
+	if (up && up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2)) {
+		spin_lock_irq(&up->port.lock);
+		omap_8250_rx_dma(up);
+		spin_unlock_irq(&up->port.lock);
+	}
+
+	priv->latency = priv->calc_latency;
+	schedule_work(&priv->qos_work);
+	return 0;
+}
+
+#ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP
+static int __init omap8250_console_fixup(void)
+{
+	char *omap_str;
+	char *options;
+	u8 idx;
+
+	if (strstr(boot_command_line, "console=ttyS"))
+		/* user set a ttyS based name for the console */
+		return 0;
+
+	omap_str = strstr(boot_command_line, "console=ttyO");
+	if (!omap_str)
+		/* user did not set ttyO based console, so we don't care */
+		return 0;
+
+	omap_str += 12;
+	if ('0' <= *omap_str && *omap_str <= '9')
+		idx = *omap_str - '0';
+	else
+		return 0;
+
+	omap_str++;
+	if (omap_str[0] == ',') {
+		omap_str++;
+		options = omap_str;
+	} else {
+		options = NULL;
+	}
+
+	add_preferred_console("ttyS", idx, options);
+	pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n",
+	       idx, idx);
+	pr_err("This ensures that you still see kernel messages. Please\n");
+	pr_err("update your kernel commandline.\n");
+	return 0;
+}
+console_initcall(omap8250_console_fixup);
+#endif
+
+static const struct dev_pm_ops omap8250_dev_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume)
+	RUNTIME_PM_OPS(omap8250_runtime_suspend,
+			   omap8250_runtime_resume, NULL)
+	.prepare        = pm_sleep_ptr(omap8250_prepare),
+	.complete       = pm_sleep_ptr(omap8250_complete),
+};
+
+static struct platform_driver omap8250_platform_driver = {
+	.driver = {
+		.name		= "omap8250",
+		.pm		= pm_ptr(&omap8250_dev_pm_ops),
+		.of_match_table = omap8250_dt_ids,
+	},
+	.probe			= omap8250_probe,
+	.remove			= omap8250_remove,
+};
+module_platform_driver(omap8250_platform_driver);
+
+MODULE_AUTHOR("Sebastian Andrzej Siewior");
+MODULE_DESCRIPTION("OMAP 8250 Driver");
+MODULE_LICENSE("GPL v2");