[PATCH v2 5/6] tty: serial: Add linflexuart driver for S32V234

[Stefan-gabriel Mirea <stefan-gabriel.mirea@nxp.com>]

Introduce support for LINFlex driver, based on:
- the version of Freescale LPUART driver after commit b3e3bf2ef2c7 ("Merge
  4.0-rc7 into tty-next");
- commit abf1e0a98083 ("tty: serial: fsl_lpuart: lock port on console
  write").
In this basic version, the driver can be tested using initramfs and relies
on the clocks and pin muxing set up by U-Boot.

Remarks concerning the earlycon support:

- LinFlexD does not allow character transmissions in the INIT mode (see
  section 47.4.2.1 in the reference manual[1]). Therefore, a mutual
  exclusion between the first linflex_setup_watermark/linflex_set_termios
  executions and linflex_earlycon_putchar was employed and the characters
  normally sent to earlycon during initialization are kept in a buffer and
  sent afterwards.

- Empirically, character transmission is also forbidden within the last 1-2
  ms before entering the INIT mode, so we use an explicit timeout
  (PREINIT_DELAY) between linflex_earlycon_putchar and the first call to
  linflex_setup_watermark.

- U-Boot currently uses the UART FIFO mode, while this driver makes the
  transition to the buffer mode. Therefore, the earlycon putchar function
  matches the U-Boot behavior before initializations and the Linux behavior
  after.

[1] https://www.nxp.com/webapp/Download?colCode=S32V234RM

Signed-off-by: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>
Signed-off-by: Adrian.Nitu <adrian.nitu@freescale.com>
Signed-off-by: Larisa Grigore <Larisa.Grigore@nxp.com>
Signed-off-by: Ana Nedelcu <B56683@freescale.com>
Signed-off-by: Mihaela Martinas <Mihaela.Martinas@freescale.com>
Signed-off-by: Matthew Nunez <matthew.nunez@nxp.com>
[stefan-gabriel.mirea@nxp.com: Reduced for upstreaming and implemented
                               earlycon support]
Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
---
 .../admin-guide/kernel-parameters.txt         |   6 +
 drivers/tty/serial/Kconfig                    |  15 +
 drivers/tty/serial/Makefile                   |   1 +
 drivers/tty/serial/fsl_linflexuart.c          | 942 ++++++++++++++++++
 include/uapi/linux/serial_core.h              |   3 +
 5 files changed, 967 insertions(+)
 create mode 100644 drivers/tty/serial/fsl_linflexuart.c

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 46b826fcb5ad..4d545732aadc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1090,6 +1090,12 @@
 			the framebuffer, pass the 'ram' option so that it is
 			mapped with the correct attributes.
 
+		linflex,<addr>
+			Use early console provided by Freescale LinFlex UART
+			serial driver for NXP S32V234 SoCs. A valid base
+			address must be provided, and the serial port must
+			already be setup and configured.
+
 	earlyprintk=	[X86,SH,ARM,M68k,S390]
 			earlyprintk=vga
 			earlyprintk=sclp
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index fd385c8c53a5..b4fa2f7c96bd 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1452,6 +1452,21 @@ config SERIAL_FSL_LPUART_CONSOLE
 	  If you have enabled the lpuart serial port on the Freescale SoCs,
 	  you can make it the console by answering Y to this option.
 
+config SERIAL_FSL_LINFLEXUART
+	tristate "Freescale linflexuart serial port support"
+	select SERIAL_CORE
+	help
+	  Support for the on-chip linflexuart on some Freescale SOCs.
+
+config SERIAL_FSL_LINFLEXUART_CONSOLE
+	bool "Console on Freescale linflexuart serial port"
+	depends on SERIAL_FSL_LINFLEXUART=y
+	select SERIAL_CORE_CONSOLE
+	select SERIAL_EARLYCON
+	help
+	  If you have enabled the linflexuart serial port on the Freescale
+	  SoCs, you can make it the console by answering Y to this option.
+
 config SERIAL_CONEXANT_DIGICOLOR
 	tristate "Conexant Digicolor CX92xxx USART serial port support"
 	depends on OF
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 7cd7cabfa6c4..7a3d52a453b7 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o
 obj-$(CONFIG_SERIAL_ARC)	+= arc_uart.o
 obj-$(CONFIG_SERIAL_RP2)	+= rp2.o
 obj-$(CONFIG_SERIAL_FSL_LPUART)	+= fsl_lpuart.o
+obj-$(CONFIG_SERIAL_FSL_LINFLEXUART)	+= fsl_linflexuart.o
 obj-$(CONFIG_SERIAL_CONEXANT_DIGICOLOR)	+= digicolor-usart.o
 obj-$(CONFIG_SERIAL_MEN_Z135)	+= men_z135_uart.o
 obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
diff --git a/drivers/tty/serial/fsl_linflexuart.c b/drivers/tty/serial/fsl_linflexuart.c
new file mode 100644
index 000000000000..26b9601a0952
--- /dev/null
+++ b/drivers/tty/serial/fsl_linflexuart.c
@@ -0,0 +1,942 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Freescale linflexuart serial port driver
+ *
+ * Copyright 2012-2016 Freescale Semiconductor, Inc.
+ * Copyright 2017-2018 NXP
+ */
+
+#if defined(CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE) && \
+	defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/console.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/serial_core.h>
+#include <linux/slab.h>
+#include <linux/tty_flip.h>
+#include <linux/delay.h>
+
+/* All registers are 32-bit width */
+
+#define LINCR1	0x0000	/* LIN control register				*/
+#define LINIER	0x0004	/* LIN interrupt enable register		*/
+#define LINSR	0x0008	/* LIN status register				*/
+#define LINESR	0x000C	/* LIN error status register			*/
+#define UARTCR	0x0010	/* UART mode control register			*/
+#define UARTSR	0x0014	/* UART mode status register			*/
+#define LINTCSR	0x0018	/* LIN timeout control status register		*/
+#define LINOCR	0x001C	/* LIN output compare register			*/
+#define LINTOCR	0x0020	/* LIN timeout control register			*/
+#define LINFBRR	0x0024	/* LIN fractional baud rate register		*/
+#define LINIBRR	0x0028	/* LIN integer baud rate register		*/
+#define LINCFR	0x002C	/* LIN checksum field register			*/
+#define LINCR2	0x0030	/* LIN control register 2			*/
+#define BIDR	0x0034	/* Buffer identifier register			*/
+#define BDRL	0x0038	/* Buffer data register least significant	*/
+#define BDRM	0x003C	/* Buffer data register most significant	*/
+#define IFER	0x0040	/* Identifier filter enable register		*/
+#define IFMI	0x0044	/* Identifier filter match index		*/
+#define IFMR	0x0048	/* Identifier filter mode register		*/
+#define GCR	0x004C	/* Global control register			*/
+#define UARTPTO	0x0050	/* UART preset timeout register			*/
+#define UARTCTO	0x0054	/* UART current timeout register		*/
+
+/*
+ * Register field definitions
+ */
+
+#define LINFLEXD_LINCR1_INIT		BIT(0)
+#define LINFLEXD_LINCR1_MME		BIT(4)
+#define LINFLEXD_LINCR1_BF		BIT(7)
+
+#define LINFLEXD_LINSR_LINS_INITMODE	BIT(12)
+#define LINFLEXD_LINSR_LINS_MASK	(0xF << 12)
+
+#define LINFLEXD_LINIER_SZIE		BIT(15)
+#define LINFLEXD_LINIER_OCIE		BIT(14)
+#define LINFLEXD_LINIER_BEIE		BIT(13)
+#define LINFLEXD_LINIER_CEIE		BIT(12)
+#define LINFLEXD_LINIER_HEIE		BIT(11)
+#define LINFLEXD_LINIER_FEIE		BIT(8)
+#define LINFLEXD_LINIER_BOIE		BIT(7)
+#define LINFLEXD_LINIER_LSIE		BIT(6)
+#define LINFLEXD_LINIER_WUIE		BIT(5)
+#define LINFLEXD_LINIER_DBFIE		BIT(4)
+#define LINFLEXD_LINIER_DBEIETOIE	BIT(3)
+#define LINFLEXD_LINIER_DRIE		BIT(2)
+#define LINFLEXD_LINIER_DTIE		BIT(1)
+#define LINFLEXD_LINIER_HRIE		BIT(0)
+
+#define LINFLEXD_UARTCR_OSR_MASK	(0xF << 24)
+#define LINFLEXD_UARTCR_OSR(uartcr)	(((uartcr) \
+					& LINFLEXD_UARTCR_OSR_MASK) >> 24)
+
+#define LINFLEXD_UARTCR_ROSE		BIT(23)
+
+#define LINFLEXD_UARTCR_RFBM		BIT(9)
+#define LINFLEXD_UARTCR_TFBM		BIT(8)
+#define LINFLEXD_UARTCR_WL1		BIT(7)
+#define LINFLEXD_UARTCR_PC1		BIT(6)
+
+#define LINFLEXD_UARTCR_RXEN		BIT(5)
+#define LINFLEXD_UARTCR_TXEN		BIT(4)
+#define LINFLEXD_UARTCR_PC0		BIT(3)
+
+#define LINFLEXD_UARTCR_PCE		BIT(2)
+#define LINFLEXD_UARTCR_WL0		BIT(1)
+#define LINFLEXD_UARTCR_UART		BIT(0)
+
+#define LINFLEXD_UARTSR_SZF		BIT(15)
+#define LINFLEXD_UARTSR_OCF		BIT(14)
+#define LINFLEXD_UARTSR_PE3		BIT(13)
+#define LINFLEXD_UARTSR_PE2		BIT(12)
+#define LINFLEXD_UARTSR_PE1		BIT(11)
+#define LINFLEXD_UARTSR_PE0		BIT(10)
+#define LINFLEXD_UARTSR_RMB		BIT(9)
+#define LINFLEXD_UARTSR_FEF		BIT(8)
+#define LINFLEXD_UARTSR_BOF		BIT(7)
+#define LINFLEXD_UARTSR_RPS		BIT(6)
+#define LINFLEXD_UARTSR_WUF		BIT(5)
+#define LINFLEXD_UARTSR_4		BIT(4)
+
+#define LINFLEXD_UARTSR_TO		BIT(3)
+
+#define LINFLEXD_UARTSR_DRFRFE		BIT(2)
+#define LINFLEXD_UARTSR_DTFTFF		BIT(1)
+#define LINFLEXD_UARTSR_NF		BIT(0)
+#define LINFLEXD_UARTSR_PE		(LINFLEXD_UARTSR_PE0 |\
+					 LINFLEXD_UARTSR_PE1 |\
+					 LINFLEXD_UARTSR_PE2 |\
+					 LINFLEXD_UARTSR_PE3)
+
+#define LINFLEX_LDIV_MULTIPLIER		(16)
+
+#define DRIVER_NAME	"fsl-linflexuart"
+#define DEV_NAME	"ttyLF"
+#define UART_NR		4
+
+#define EARLYCON_BUFFER_INITIAL_CAP	8
+
+#define PREINIT_DELAY			2000 /* us */
+
+static const struct of_device_id linflex_dt_ids[] = {
+	{
+		.compatible = "fsl,s32-linflexuart",
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, linflex_dt_ids);
+
+#ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
+static struct uart_port *earlycon_port;
+static bool linflex_earlycon_same_instance;
+static spinlock_t init_lock;
+static bool during_init;
+
+static struct {
+	char *content;
+	unsigned int len, cap;
+} earlycon_buf;
+#endif
+
+static void linflex_stop_tx(struct uart_port *port)
+{
+	unsigned long ier;
+
+	ier = readl(port->membase + LINIER);
+	ier &= ~(LINFLEXD_LINIER_DTIE);
+	writel(ier, port->membase + LINIER);
+}
+
+static void linflex_stop_rx(struct uart_port *port)
+{
+	unsigned long ier;
+
+	ier = readl(port->membase + LINIER);
+	writel(ier & ~LINFLEXD_LINIER_DRIE, port->membase + LINIER);
+}
+
+static inline void linflex_transmit_buffer(struct uart_port *sport)
+{
+	struct circ_buf *xmit = &sport->state->xmit;
+	unsigned char c;
+	unsigned long status;
+
+	while (!uart_circ_empty(xmit)) {
+		c = xmit->buf[xmit->tail];
+		writeb(c, sport->membase + BDRL);
+
+		/* Waiting for data transmission completed. */
+		while (((status = readl(sport->membase + UARTSR)) &
+					LINFLEXD_UARTSR_DTFTFF) !=
+					LINFLEXD_UARTSR_DTFTFF)
+			;
+
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		sport->icount.tx++;
+
+		writel(status | LINFLEXD_UARTSR_DTFTFF,
+		       sport->membase + UARTSR);
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(sport);
+
+	if (uart_circ_empty(xmit))
+		linflex_stop_tx(sport);
+}
+
+static void linflex_start_tx(struct uart_port *port)
+{
+	unsigned long ier;
+
+	linflex_transmit_buffer(port);
+	ier = readl(port->membase + LINIER);
+	writel(ier | LINFLEXD_LINIER_DTIE, port->membase + LINIER);
+}
+
+static irqreturn_t linflex_txint(int irq, void *dev_id)
+{
+	struct uart_port *sport = dev_id;
+	struct circ_buf *xmit = &sport->state->xmit;
+	unsigned long flags;
+	unsigned long status;
+
+	spin_lock_irqsave(&sport->lock, flags);
+
+	if (sport->x_char) {
+		writeb(sport->x_char, sport->membase + BDRL);
+
+		/* waiting for data transmission completed */
+		while (((status = readl(sport->membase + UARTSR)) &
+			LINFLEXD_UARTSR_DTFTFF) != LINFLEXD_UARTSR_DTFTFF)
+			;
+
+		writel(status | LINFLEXD_UARTSR_DTFTFF,
+		       sport->membase + UARTSR);
+
+		goto out;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(sport)) {
+		linflex_stop_tx(sport);
+		goto out;
+	}
+
+	linflex_transmit_buffer(sport);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(sport);
+
+out:
+	spin_unlock_irqrestore(&sport->lock, flags);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t linflex_rxint(int irq, void *dev_id)
+{
+	struct uart_port *sport = dev_id;
+	unsigned int flg;
+	struct tty_port *port = &sport->state->port;
+	unsigned long flags, status;
+	unsigned char rx;
+
+	spin_lock_irqsave(&sport->lock, flags);
+
+	status = readl(sport->membase + UARTSR);
+	while (status & LINFLEXD_UARTSR_RMB) {
+		rx = readb(sport->membase + BDRM);
+		flg = TTY_NORMAL;
+		sport->icount.rx++;
+
+		if (status & (LINFLEXD_UARTSR_BOF | LINFLEXD_UARTSR_SZF |
+			      LINFLEXD_UARTSR_FEF | LINFLEXD_UARTSR_PE)) {
+			if (status & LINFLEXD_UARTSR_SZF)
+				status |= LINFLEXD_UARTSR_SZF;
+			if (status & LINFLEXD_UARTSR_BOF)
+				status |= LINFLEXD_UARTSR_BOF;
+			if (status & LINFLEXD_UARTSR_FEF)
+				status |= LINFLEXD_UARTSR_FEF;
+			if (status & LINFLEXD_UARTSR_PE)
+				status |=  LINFLEXD_UARTSR_PE;
+		}
+
+		writel(status | LINFLEXD_UARTSR_RMB | LINFLEXD_UARTSR_DRFRFE,
+		       sport->membase + UARTSR);
+		status = readl(sport->membase + UARTSR);
+
+		if (uart_handle_sysrq_char(sport, (unsigned char)rx))
+			continue;
+
+#ifdef SUPPORT_SYSRQ
+			sport->sysrq = 0;
+#endif
+		tty_insert_flip_char(port, rx, flg);
+	}
+
+	spin_unlock_irqrestore(&sport->lock, flags);
+
+	tty_flip_buffer_push(port);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t linflex_int(int irq, void *dev_id)
+{
+	struct uart_port *sport = dev_id;
+	unsigned long status;
+
+	status = readl(sport->membase + UARTSR);
+
+	if (status & LINFLEXD_UARTSR_DRFRFE)
+		linflex_rxint(irq, dev_id);
+	if (status & LINFLEXD_UARTSR_DTFTFF)
+		linflex_txint(irq, dev_id);
+
+	return IRQ_HANDLED;
+}
+
+/* return TIOCSER_TEMT when transmitter is not busy */
+static unsigned int linflex_tx_empty(struct uart_port *port)
+{
+	unsigned long status;
+
+	status = readl(port->membase + UARTSR) & LINFLEXD_UARTSR_DTFTFF;
+
+	return status ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int linflex_get_mctrl(struct uart_port *port)
+{
+	return 0;
+}
+
+static void linflex_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+}
+
+static void linflex_break_ctl(struct uart_port *port, int break_state)
+{
+}
+
+static void linflex_setup_watermark(struct uart_port *sport)
+{
+	unsigned long cr, ier, cr1;
+
+	/* Disable transmission/reception */
+	ier = readl(sport->membase + LINIER);
+	ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE);
+	writel(ier, sport->membase + LINIER);
+
+	cr = readl(sport->membase + UARTCR);
+	cr &= ~(LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN);
+	writel(cr, sport->membase + UARTCR);
+
+	/* Enter initialization mode by setting INIT bit */
+
+	/* set the Linflex in master mode and activate by-pass filter */
+	cr1 = LINFLEXD_LINCR1_BF | LINFLEXD_LINCR1_MME
+	      | LINFLEXD_LINCR1_INIT;
+	writel(cr1, sport->membase + LINCR1);
+
+	/* wait for init mode entry */
+	while ((readl(sport->membase + LINSR)
+		& LINFLEXD_LINSR_LINS_MASK)
+		!= LINFLEXD_LINSR_LINS_INITMODE)
+		;
+
+	/*
+	 *	UART = 0x1;		- Linflex working in UART mode
+	 *	TXEN = 0x1;		- Enable transmission of data now
+	 *	RXEn = 0x1;		- Receiver enabled
+	 *	WL0 = 0x1;		- 8 bit data
+	 *	PCE = 0x0;		- No parity
+	 */
+
+	/* set UART bit to allow writing other bits */
+	writel(LINFLEXD_UARTCR_UART, sport->membase + UARTCR);
+
+	cr = (LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN |
+	      LINFLEXD_UARTCR_WL0 | LINFLEXD_UARTCR_UART);
+
+	writel(cr, sport->membase + UARTCR);
+
+	cr1 &= ~(LINFLEXD_LINCR1_INIT);
+
+	writel(cr1, sport->membase + LINCR1);
+
+	ier = readl(sport->membase + LINIER);
+	ier |= LINFLEXD_LINIER_DRIE;
+	ier |= LINFLEXD_LINIER_DTIE;
+
+	writel(ier, sport->membase + LINIER);
+}
+
+static int linflex_startup(struct uart_port *port)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	linflex_setup_watermark(port);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	ret = devm_request_irq(port->dev, port->irq, linflex_int, 0,
+			       DRIVER_NAME, port);
+
+	return ret;
+}
+
+static void linflex_shutdown(struct uart_port *port)
+{
+	unsigned long ier;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	/* disable interrupts */
+	ier = readl(port->membase + LINIER);
+	ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE);
+	writel(ier, port->membase + LINIER);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	devm_free_irq(port->dev, port->irq, port);
+}
+
+static void
+linflex_set_termios(struct uart_port *port, struct ktermios *termios,
+		    struct ktermios *old)
+{
+	unsigned long flags;
+	unsigned long cr, old_cr, cr1;
+	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
+
+	cr = readl(port->membase + UARTCR);
+	old_cr = cr;
+
+	/* Enter initialization mode by setting INIT bit */
+	cr1 = readl(port->membase + LINCR1);
+	cr1 |= LINFLEXD_LINCR1_INIT;
+	writel(cr1, port->membase + LINCR1);
+
+	/* wait for init mode entry */
+	while ((readl(port->membase + LINSR)
+		& LINFLEXD_LINSR_LINS_MASK)
+		!= LINFLEXD_LINSR_LINS_INITMODE)
+		;
+
+	/*
+	 * only support CS8 and CS7, and for CS7 must enable PE.
+	 * supported mode:
+	 *	- (7,e/o,1)
+	 *	- (8,n,1)
+	 *	- (8,e/o,1)
+	 */
+	/* enter the UART into configuration mode */
+
+	while ((termios->c_cflag & CSIZE) != CS8 &&
+	       (termios->c_cflag & CSIZE) != CS7) {
+		termios->c_cflag &= ~CSIZE;
+		termios->c_cflag |= old_csize;
+		old_csize = CS8;
+	}
+
+	if ((termios->c_cflag & CSIZE) == CS7) {
+		/* Word length: WL1WL0:00 */
+		cr = old_cr & ~LINFLEXD_UARTCR_WL1 & ~LINFLEXD_UARTCR_WL0;
+	}
+
+	if ((termios->c_cflag & CSIZE) == CS8) {
+		/* Word length: WL1WL0:01 */
+		cr = (old_cr | LINFLEXD_UARTCR_WL0) & ~LINFLEXD_UARTCR_WL1;
+	}
+
+	if (termios->c_cflag & CMSPAR) {
+		if ((termios->c_cflag & CSIZE) != CS8) {
+			termios->c_cflag &= ~CSIZE;
+			termios->c_cflag |= CS8;
+		}
+		/* has a space/sticky bit */
+		cr |= LINFLEXD_UARTCR_WL0;
+	}
+
+	if (termios->c_cflag & CSTOPB)
+		termios->c_cflag &= ~CSTOPB;
+
+	/* parity must be enabled when CS7 to match 8-bits format */
+	if ((termios->c_cflag & CSIZE) == CS7)
+		termios->c_cflag |= PARENB;
+
+	if ((termios->c_cflag & PARENB)) {
+		cr |= LINFLEXD_UARTCR_PCE;
+		if (termios->c_cflag & PARODD)
+			cr = (cr | LINFLEXD_UARTCR_PC0) &
+			     (~LINFLEXD_UARTCR_PC1);
+		else
+			cr = cr & (~LINFLEXD_UARTCR_PC1 &
+				   ~LINFLEXD_UARTCR_PC0);
+	} else {
+		cr &= ~LINFLEXD_UARTCR_PCE;
+	}
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	port->read_status_mask = 0;
+
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |=	(LINFLEXD_UARTSR_FEF |
+						 LINFLEXD_UARTSR_PE0 |
+						 LINFLEXD_UARTSR_PE1 |
+						 LINFLEXD_UARTSR_PE2 |
+						 LINFLEXD_UARTSR_PE3);
+	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
+		port->read_status_mask |= LINFLEXD_UARTSR_FEF;
+
+	/* characters to ignore */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= LINFLEXD_UARTSR_PE;
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= LINFLEXD_UARTSR_PE;
+		/*
+		 * if we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= LINFLEXD_UARTSR_BOF;
+	}
+
+	writel(cr, port->membase + UARTCR);
+
+	cr1 &= ~(LINFLEXD_LINCR1_INIT);
+
+	writel(cr1, port->membase + LINCR1);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *linflex_type(struct uart_port *port)
+{
+	return "FSL_LINFLEX";
+}
+
+static void linflex_release_port(struct uart_port *port)
+{
+	/* nothing to do */
+}
+
+static int linflex_request_port(struct uart_port *port)
+{
+	return 0;
+}
+
+/* configure/auto-configure the port */
+static void linflex_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE)
+		port->type = PORT_LINFLEXUART;
+}
+
+static const struct uart_ops linflex_pops = {
+	.tx_empty	= linflex_tx_empty,
+	.set_mctrl	= linflex_set_mctrl,
+	.get_mctrl	= linflex_get_mctrl,
+	.stop_tx	= linflex_stop_tx,
+	.start_tx	= linflex_start_tx,
+	.stop_rx	= linflex_stop_rx,
+	.break_ctl	= linflex_break_ctl,
+	.startup	= linflex_startup,
+	.shutdown	= linflex_shutdown,
+	.set_termios	= linflex_set_termios,
+	.type		= linflex_type,
+	.request_port	= linflex_request_port,
+	.release_port	= linflex_release_port,
+	.config_port	= linflex_config_port,
+};
+
+static struct uart_port *linflex_ports[UART_NR];
+
+#ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
+static void linflex_console_putchar(struct uart_port *port, int ch)
+{
+	unsigned long cr;
+
+	cr = readl(port->membase + UARTCR);
+
+	writeb(ch, port->membase + BDRL);
+
+	if (!(cr & LINFLEXD_UARTCR_TFBM))
+		while ((readl(port->membase + UARTSR) &
+					LINFLEXD_UARTSR_DTFTFF)
+				!= LINFLEXD_UARTSR_DTFTFF)
+			;
+	else
+		while (readl(port->membase + UARTSR) &
+					LINFLEXD_UARTSR_DTFTFF)
+			;
+
+	if (!(cr & LINFLEXD_UARTCR_TFBM)) {
+		writel((readl(port->membase + UARTSR) |
+					LINFLEXD_UARTSR_DTFTFF),
+					port->membase + UARTSR);
+	}
+}
+
+static void linflex_earlycon_putchar(struct uart_port *port, int ch)
+{
+	unsigned long flags;
+	char *ret;
+
+	if (!linflex_earlycon_same_instance) {
+		linflex_console_putchar(port, ch);
+		return;
+	}
+
+	spin_lock_irqsave(&init_lock, flags);
+	if (!during_init)
+		goto outside_init;
+
+	if (earlycon_buf.len >= 1 << CONFIG_LOG_BUF_SHIFT)
+		goto init_release;
+
+	if (!earlycon_buf.cap) {
+		earlycon_buf.content = kmalloc(EARLYCON_BUFFER_INITIAL_CAP,
+					       GFP_ATOMIC);
+		earlycon_buf.cap = earlycon_buf.content ?
+				   EARLYCON_BUFFER_INITIAL_CAP : 0;
+	} else if (earlycon_buf.len == earlycon_buf.cap) {
+		ret = krealloc(earlycon_buf.content, earlycon_buf.cap << 1,
+			       GFP_ATOMIC);
+		if (ret) {
+			earlycon_buf.content = ret;
+			earlycon_buf.cap <<= 1;
+		}
+	}
+
+	if (earlycon_buf.len < earlycon_buf.cap)
+		earlycon_buf.content[earlycon_buf.len++] = ch;
+
+	goto init_release;
+
+outside_init:
+	linflex_console_putchar(port, ch);
+init_release:
+	spin_unlock_irqrestore(&init_lock, flags);
+}
+
+static void linflex_string_write(struct uart_port *sport, const char *s,
+				 unsigned int count)
+{
+	unsigned long cr, ier = 0;
+
+	ier = readl(sport->membase + LINIER);
+	linflex_stop_tx(sport);
+
+	cr = readl(sport->membase + UARTCR);
+	cr |= (LINFLEXD_UARTCR_TXEN);
+	writel(cr, sport->membase + UARTCR);
+
+	uart_console_write(sport, s, count, linflex_console_putchar);
+
+	writel(ier, sport->membase + LINIER);
+}
+
+static void
+linflex_console_write(struct console *co, const char *s, unsigned int count)
+{
+	struct uart_port *sport = linflex_ports[co->index];
+	unsigned long flags;
+	int locked = 1;
+
+	if (sport->sysrq)
+		locked = 0;
+	else if (oops_in_progress)
+		locked = spin_trylock_irqsave(&sport->lock, flags);
+	else
+		spin_lock_irqsave(&sport->lock, flags);
+
+	linflex_string_write(sport, s, count);
+
+	if (locked)
+		spin_unlock_irqrestore(&sport->lock, flags);
+}
+
+/*
+ * if the port was already initialised (eg, by a boot loader),
+ * try to determine the current setup.
+ */
+static void __init
+linflex_console_get_options(struct uart_port *sport, int *parity, int *bits)
+{
+	unsigned long cr;
+
+	cr = readl(sport->membase + UARTCR);
+	cr &= LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN;
+
+	if (!cr)
+		return;
+
+	/* ok, the port was enabled */
+
+	*parity = 'n';
+	if (cr & LINFLEXD_UARTCR_PCE) {
+		if (cr & LINFLEXD_UARTCR_PC0)
+			*parity = 'o';
+		else
+			*parity = 'e';
+	}
+
+	if ((cr & LINFLEXD_UARTCR_WL0) && ((cr & LINFLEXD_UARTCR_WL1) == 0)) {
+		if (cr & LINFLEXD_UARTCR_PCE)
+			*bits = 9;
+		else
+			*bits = 8;
+	}
+}
+
+static int __init linflex_console_setup(struct console *co, char *options)
+{
+	struct uart_port *sport;
+	int baud = 115200;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+	int ret;
+	int i;
+	unsigned long flags;
+	/*
+	 * check whether an invalid uart number has been specified, and
+	 * if so, search for the first available port that does have
+	 * console support.
+	 */
+	if (co->index == -1 || co->index >= ARRAY_SIZE(linflex_ports))
+		co->index = 0;
+
+	sport = linflex_ports[co->index];
+	if (!sport)
+		return -ENODEV;
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else
+		linflex_console_get_options(sport, &parity, &bits);
+
+	if (earlycon_port && sport->mapbase == earlycon_port->mapbase) {
+		linflex_earlycon_same_instance = true;
+
+		spin_lock_irqsave(&init_lock, flags);
+		during_init = true;
+		spin_unlock_irqrestore(&init_lock, flags);
+
+		/* Workaround for character loss or output of many invalid
+		 * characters, when INIT mode is entered shortly after a
+		 * character has just been printed.
+		 */
+		udelay(PREINIT_DELAY);
+	}
+
+	linflex_setup_watermark(sport);
+
+	ret = uart_set_options(sport, co, baud, parity, bits, flow);
+
+	if (!linflex_earlycon_same_instance)
+		goto done;
+
+	spin_lock_irqsave(&init_lock, flags);
+
+	/* Emptying buffer */
+	if (earlycon_buf.len) {
+		for (i = 0; i < earlycon_buf.len; i++)
+			linflex_console_putchar(earlycon_port,
+				earlycon_buf.content[i]);
+
+		kfree(earlycon_buf.content);
+		earlycon_buf.len = 0;
+	}
+
+	during_init = false;
+	spin_unlock_irqrestore(&init_lock, flags);
+
+done:
+	return ret;
+}
+
+static struct uart_driver linflex_reg;
+static struct console linflex_console = {
+	.name		= DEV_NAME,
+	.write		= linflex_console_write,
+	.device		= uart_console_device,
+	.setup		= linflex_console_setup,
+	.flags		= CON_PRINTBUFFER,
+	.index		= -1,
+	.data		= &linflex_reg,
+};
+
+static void linflex_earlycon_write(struct console *con, const char *s,
+				   unsigned int n)
+{
+	struct earlycon_device *dev = con->data;
+
+	uart_console_write(&dev->port, s, n, linflex_earlycon_putchar);
+}
+
+static int __init linflex_early_console_setup(struct earlycon_device *device,
+					      const char *options)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	device->con->write = linflex_earlycon_write;
+	earlycon_port = &device->port;
+
+	return 0;
+}
+
+OF_EARLYCON_DECLARE(linflex, "fsl,s32-linflexuart",
+		    linflex_early_console_setup);
+
+#define LINFLEX_CONSOLE	(&linflex_console)
+#else
+#define LINFLEX_CONSOLE	NULL
+#endif
+
+static struct uart_driver linflex_reg = {
+	.owner		= THIS_MODULE,
+	.driver_name	= DRIVER_NAME,
+	.dev_name	= DEV_NAME,
+	.nr		= ARRAY_SIZE(linflex_ports),
+	.cons		= LINFLEX_CONSOLE,
+};
+
+static int linflex_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct uart_port *sport;
+	struct resource *res;
+	int ret;
+
+	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
+	if (!sport)
+		return -ENOMEM;
+
+	ret = of_alias_get_id(np, "serial");
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
+		return ret;
+	}
+	if (ret >= UART_NR) {
+		dev_err(&pdev->dev, "driver limited to %d serial ports\n",
+			UART_NR);
+		return -ENOMEM;
+	}
+
+	sport->line = ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	sport->mapbase = res->start;
+	sport->membase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sport->membase))
+		return PTR_ERR(sport->membase);
+
+	sport->dev = &pdev->dev;
+	sport->type = PORT_LINFLEXUART;
+	sport->iotype = UPIO_MEM;
+	sport->irq = platform_get_irq(pdev, 0);
+	sport->ops = &linflex_pops;
+	sport->flags = UPF_BOOT_AUTOCONF;
+
+	linflex_ports[sport->line] = sport;
+
+	platform_set_drvdata(pdev, sport);
+
+	ret = uart_add_one_port(&linflex_reg, sport);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int linflex_remove(struct platform_device *pdev)
+{
+	struct uart_port *sport = platform_get_drvdata(pdev);
+
+	uart_remove_one_port(&linflex_reg, sport);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int linflex_suspend(struct device *dev)
+{
+	struct uart_port *sport = dev_get_drvdata(dev);
+
+	uart_suspend_port(&linflex_reg, sport);
+
+	return 0;
+}
+
+static int linflex_resume(struct device *dev)
+{
+	struct uart_port *sport = dev_get_drvdata(dev);
+
+	uart_resume_port(&linflex_reg, sport);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(linflex_pm_ops, linflex_suspend, linflex_resume);
+
+static struct platform_driver linflex_driver = {
+	.probe		= linflex_probe,
+	.remove		= linflex_remove,
+	.driver		= {
+		.name	= DRIVER_NAME,
+		.owner	= THIS_MODULE,
+		.of_match_table	= linflex_dt_ids,
+		.pm	= &linflex_pm_ops,
+	},
+};
+
+static int __init linflex_serial_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&linflex_reg);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&linflex_driver);
+	if (ret)
+		uart_unregister_driver(&linflex_reg);
+
+#ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
+	spin_lock_init(&init_lock);
+#endif
+
+	return ret;
+}
+
+static void __exit linflex_serial_exit(void)
+{
+	platform_driver_unregister(&linflex_driver);
+	uart_unregister_driver(&linflex_reg);
+}
+
+module_init(linflex_serial_init);
+module_exit(linflex_serial_exit);
+
+MODULE_DESCRIPTION("Freescale linflex serial port driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index 5642c05e0da0..25a3dead4473 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -293,4 +293,7 @@
 /* SiFive UART */
 #define PORT_SIFIVE_V0	120
 
+/* Freescale Linflex UART */
+#define PORT_LINFLEXUART	121
+
 #endif /* _UAPILINUX_SERIAL_CORE_H */
-- 
2.22.0


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