drivers/serial/ns16550.c - platform/external/u-boot - Gitiles

 /*
  * COM1 NS16550 support
  * originally from linux source (arch/powerpc/boot/ns16550.c)
  * modified to use CONFIG_SYS_ISA_MEM and new defines
  */

 #include <clock_legacy.h>
 #include <common.h>
 #include <clk.h>
 #include <dm.h>
 #include <errno.h>
 #include <log.h>
 #include <ns16550.h>
 #include <reset.h>
 #include <serial.h>
 #include <watchdog.h>
 #include <asm/global_data.h>
 #include <linux/err.h>
 #include <linux/types.h>
 #include <asm/io.h>

 DECLARE_GLOBAL_DATA_PTR;

 #define UART_LCRVAL UART_LCR_8N1		/* 8 data, 1 stop, no parity */
 #define UART_MCRVAL (UART_MCR_DTR | \
 		     UART_MCR_RTS)		/* RTS/DTR */

 #if !CONFIG_IS_ENABLED(DM_SERIAL)
 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
 #define serial_out(x, y)	outb(x, (ulong)y)
 #define serial_in(y)		inb((ulong)y)
 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
 #define serial_out(x, y)	out_be32(y, x)
 #define serial_in(y)		in_be32(y)
 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
 #define serial_out(x, y)	out_le32(y, x)
 #define serial_in(y)		in_le32(y)
 #else
 #define serial_out(x, y)	writeb(x, y)
 #define serial_in(y)		readb(y)
 #endif
 #endif /* !CONFIG_DM_SERIAL */

 #if defined(CONFIG_ARCH_KEYSTONE)
 #define UART_REG_VAL_PWREMU_MGMT_UART_DISABLE   0
 #define UART_REG_VAL_PWREMU_MGMT_UART_ENABLE ((1 << 14) | (1 << 13) | (1 << 0))
 #undef UART_MCRVAL
 #ifdef CONFIG_SERIAL_HW_FLOW_CONTROL
 #define UART_MCRVAL             (UART_MCR_RTS | UART_MCR_AFE)
 #else
 #define UART_MCRVAL             (UART_MCR_RTS)
 #endif
 #endif

 #ifndef CONFIG_SYS_NS16550_IER
 #define CONFIG_SYS_NS16550_IER  0x00
 #endif /* CONFIG_SYS_NS16550_IER */

 static inline void serial_out_shift(void *addr, int shift, int value)
 {
 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
 	outb(value, (ulong)addr);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_LITTLE_ENDIAN)
 	out_le32(addr, value);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
 	out_be32(addr, value);
 #elif defined(CONFIG_SYS_NS16550_MEM32)
 	writel(value, addr);
 #elif defined(CONFIG_SYS_BIG_ENDIAN)
 	writeb(value, addr + (1 << shift) - 1);
 #else
 	writeb(value, addr);
 #endif
 }

 static inline int serial_in_shift(void *addr, int shift)
 {
 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
 	return inb((ulong)addr);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_LITTLE_ENDIAN)
 	return in_le32(addr);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
 	return in_be32(addr);
 #elif defined(CONFIG_SYS_NS16550_MEM32)
 	return readl(addr);
 #elif defined(CONFIG_SYS_BIG_ENDIAN)
 	return readb(addr + (1 << shift) - 1);
 #else
 	return readb(addr);
 #endif
 }

 #if CONFIG_IS_ENABLED(DM_SERIAL)

 #ifndef CONFIG_SYS_NS16550_CLK
 #define CONFIG_SYS_NS16550_CLK  0
 #endif

 /*
  * Use this #ifdef for now since many platforms don't define in(), out(),
  * out_le32(), etc. but we don't have #defines to indicate this.
  *
  * TODO(sjg@chromium.org): Add CONFIG options to indicate what I/O is available
  * on a platform
  */
 #ifdef CONFIG_NS16550_DYNAMIC
 static void serial_out_dynamic(struct ns16550_plat *plat, u8 *addr,
 			       int value)
 {
 	if (plat->flags & NS16550_FLAG_IO) {
 		outb(value, addr);
 	} else if (plat->reg_width == 4) {
 		if (plat->flags & NS16550_FLAG_ENDIAN) {
 			if (plat->flags & NS16550_FLAG_BE)
 				out_be32(addr, value);
 			else
 				out_le32(addr, value);
 		} else {
 			writel(value, addr);
 		}
 	} else if (plat->flags & NS16550_FLAG_BE) {
 		writeb(value, addr + (1 << plat->reg_shift) - 1);
 	} else {
 		writeb(value, addr);
 	}
 }

 static int serial_in_dynamic(struct ns16550_plat *plat, u8 *addr)
 {
 	if (plat->flags & NS16550_FLAG_IO) {
 		return inb(addr);
 	} else if (plat->reg_width == 4) {
 		if (plat->flags & NS16550_FLAG_ENDIAN) {
 			if (plat->flags & NS16550_FLAG_BE)
 				return in_be32(addr);
 			else
 				return in_le32(addr);
 		} else {
 			return readl(addr);
 		}
 	} else if (plat->flags & NS16550_FLAG_BE) {
 		return readb(addr + (1 << plat->reg_shift) - 1);
 	} else {
 		return readb(addr);
 	}
 }
 #else
 static inline void serial_out_dynamic(struct ns16550_plat *plat, u8 *addr,
 				      int value)
 {
 }

 static inline int serial_in_dynamic(struct ns16550_plat *plat, u8 *addr)
 {
 	return 0;
 }

 #endif /* CONFIG_NS16550_DYNAMIC */

 static void ns16550_writeb(struct ns16550 *port, int offset, int value)
 {
 	struct ns16550_plat *plat = port->plat;
 	unsigned char *addr;

 	offset *= 1 << plat->reg_shift;
 	addr = (unsigned char *)plat->base + offset + plat->reg_offset;

 	if (IS_ENABLED(CONFIG_NS16550_DYNAMIC))
 		serial_out_dynamic(plat, addr, value);
 	else
 		serial_out_shift(addr, plat->reg_shift, value);
 }

 static int ns16550_readb(struct ns16550 *port, int offset)
 {
 	struct ns16550_plat *plat = port->plat;
 	unsigned char *addr;

 	offset *= 1 << plat->reg_shift;
 	addr = (unsigned char *)plat->base + offset + plat->reg_offset;

 	if (IS_ENABLED(CONFIG_NS16550_DYNAMIC))
 		return serial_in_dynamic(plat, addr);
 	else
 		return serial_in_shift(addr, plat->reg_shift);
 }

 static u32 ns16550_getfcr(struct ns16550 *port)
 {
 	struct ns16550_plat *plat = port->plat;

 	return plat->fcr;
 }

 /* We can clean these up once everything is moved to driver model */
 #define serial_out(value, addr)	\
 	ns16550_writeb(com_port, \
 		(unsigned char *)addr - (unsigned char *)com_port, value)
 #define serial_in(addr) \
 	ns16550_readb(com_port, \
 		(unsigned char *)addr - (unsigned char *)com_port)
 #else
 static u32 ns16550_getfcr(struct ns16550 *port)
 {
 	return UART_FCR_DEFVAL;
 }
 #endif

 int ns16550_calc_divisor(struct ns16550 *port, int clock, int baudrate)
 {
 	const unsigned int mode_x_div = 16;

 	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
 }

 static void ns16550_setbrg(struct ns16550 *com_port, int baud_divisor)
 {
 	/* to keep serial format, read lcr before writing BKSE */
 	int lcr_val = serial_in(&com_port->lcr) & ~UART_LCR_BKSE;

 	serial_out(UART_LCR_BKSE | lcr_val, &com_port->lcr);
 	serial_out(baud_divisor & 0xff, &com_port->dll);
 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
 	serial_out(lcr_val, &com_port->lcr);
 }

 void ns16550_init(struct ns16550 *com_port, int baud_divisor)
 {
 #if (defined(CONFIG_SPL_BUILD) && \
 		(defined(CONFIG_OMAP34XX) || defined(CONFIG_OMAP44XX)))
 	/*
 	 * On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
 	 * before SPL starts only THRE bit is set. We have to empty the
 	 * transmitter before initialization starts.
 	 */
 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
 	     == UART_LSR_THRE) {
 		if (baud_divisor != -1)
 			ns16550_setbrg(com_port, baud_divisor);
 		else {
 			// Re-use old baud rate divisor to flush transmit reg.
 			const int dll = serial_in(&com_port->dll);
 			const int dlm = serial_in(&com_port->dlm);
 			const int divisor = dll | (dlm << 8);
 			ns16550_setbrg(com_port, divisor);
 		}
 		serial_out(0, &com_port->mdr1);
 	}
 #endif

 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
 		;

 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
 #if defined(CONFIG_ARCH_OMAP2PLUS) || defined(CONFIG_OMAP_SERIAL)
 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
 #endif

 	serial_out(UART_MCRVAL, &com_port->mcr);
 	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
 	/* initialize serial config to 8N1 before writing baudrate */
 	serial_out(UART_LCRVAL, &com_port->lcr);
 	if (baud_divisor != -1)
 		ns16550_setbrg(com_port, baud_divisor);
 #if defined(CONFIG_ARCH_OMAP2PLUS) || defined(CONFIG_SOC_DA8XX) || \
 	defined(CONFIG_OMAP_SERIAL)
 	/* /16 is proper to hit 115200 with 48MHz */
 	serial_out(0, &com_port->mdr1);
 #endif
 #if defined(CONFIG_ARCH_KEYSTONE)
 	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
 #endif
 }

 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
 void ns16550_reinit(struct ns16550 *com_port, int baud_divisor)
 {
 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
 	ns16550_setbrg(com_port, 0);
 	serial_out(UART_MCRVAL, &com_port->mcr);
 	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
 	ns16550_setbrg(com_port, baud_divisor);
 }
 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */

 void ns16550_putc(struct ns16550 *com_port, char c)
 {
 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
 		;
 	serial_out(c, &com_port->thr);

 	/*
 	 * Call watchdog_reset() upon newline. This is done here in putc
 	 * since the environment code uses a single puts() to print the complete
 	 * environment upon "printenv". So we can't put this watchdog call
 	 * in puts().
 	 */
 	if (c == '\n')
 		WATCHDOG_RESET();
 }

 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
 char ns16550_getc(struct ns16550 *com_port)
 {
 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
 		extern void usbtty_poll(void);
 		usbtty_poll();
 #endif
 		WATCHDOG_RESET();
 	}
 	return serial_in(&com_port->rbr);
 }

 int ns16550_tstc(struct ns16550 *com_port)
 {
 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
 }

 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */

 #ifdef CONFIG_DEBUG_UART_NS16550

 #include <debug_uart.h>

 static inline void _debug_uart_init(void)
 {
 	struct ns16550 *com_port = (struct ns16550 *)CONFIG_DEBUG_UART_BASE;
 	int baud_divisor;

 	/*
 	 * We copy the code from above because it is already horribly messy.
 	 * Trying to refactor to nicely remove the duplication doesn't seem
 	 * feasible. The better fix is to move all users of this driver to
 	 * driver model.
 	 */
 	baud_divisor = ns16550_calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
 					    CONFIG_BAUDRATE);
 	serial_dout(&com_port->ier, CONFIG_SYS_NS16550_IER);
 	serial_dout(&com_port->mcr, UART_MCRVAL);
 	serial_dout(&com_port->fcr, UART_FCR_DEFVAL);

 	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
 	serial_dout(&com_port->dll, baud_divisor & 0xff);
 	serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
 	serial_dout(&com_port->lcr, UART_LCRVAL);
 }

 static inline int NS16550_read_baud_divisor(struct ns16550 *com_port)
 {
 	int ret;

 	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
 	ret = serial_din(&com_port->dll) & 0xff;
 	ret |= (serial_din(&com_port->dlm) & 0xff) << 8;
 	serial_dout(&com_port->lcr, UART_LCRVAL);

 	return ret;
 }

 static inline void _debug_uart_putc(int ch)
 {
 	struct ns16550 *com_port = (struct ns16550 *)CONFIG_DEBUG_UART_BASE;

 	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE)) {
 #ifdef CONFIG_DEBUG_UART_NS16550_CHECK_ENABLED
 		if (!NS16550_read_baud_divisor(com_port))
 			return;
 #endif
 	}
 	serial_dout(&com_port->thr, ch);
 }

 DEBUG_UART_FUNCS

 #endif

 #if CONFIG_IS_ENABLED(DM_SERIAL)
 static int ns16550_serial_putc(struct udevice *dev, const char ch)
 {
 	struct ns16550 *const com_port = dev_get_priv(dev);

 	if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
 		return -EAGAIN;
 	serial_out(ch, &com_port->thr);

 	/*
 	 * Call watchdog_reset() upon newline. This is done here in putc
 	 * since the environment code uses a single puts() to print the complete
 	 * environment upon "printenv". So we can't put this watchdog call
 	 * in puts().
 	 */
 	if (ch == '\n')
 		WATCHDOG_RESET();

 	return 0;
 }

 static int ns16550_serial_pending(struct udevice *dev, bool input)
 {
 	struct ns16550 *const com_port = dev_get_priv(dev);

 	if (input)
 		return (serial_in(&com_port->lsr) & UART_LSR_DR) ? 1 : 0;
 	else
 		return (serial_in(&com_port->lsr) & UART_LSR_THRE) ? 0 : 1;
 }

 static int ns16550_serial_getc(struct udevice *dev)
 {
 	struct ns16550 *const com_port = dev_get_priv(dev);

 	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
 		return -EAGAIN;

 	return serial_in(&com_port->rbr);
 }

 static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
 {
 	struct ns16550 *const com_port = dev_get_priv(dev);
 	struct ns16550_plat *plat = com_port->plat;
 	int clock_divisor;

 	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);

 	ns16550_setbrg(com_port, clock_divisor);

 	return 0;
 }

 static int ns16550_serial_setconfig(struct udevice *dev, uint serial_config)
 {
 	struct ns16550 *const com_port = dev_get_priv(dev);
 	int lcr_val = UART_LCR_WLS_8;
 	uint parity = SERIAL_GET_PARITY(serial_config);
 	uint bits = SERIAL_GET_BITS(serial_config);
 	uint stop = SERIAL_GET_STOP(serial_config);

 	/*
 	 * only parity config is implemented, check if other serial settings
 	 * are the default one.
 	 */
 	if (bits != SERIAL_8_BITS || stop != SERIAL_ONE_STOP)
 		return -ENOTSUPP; /* not supported in driver*/

 	switch (parity) {
 	case SERIAL_PAR_NONE:
 		/* no bits to add */
 		break;
 	case SERIAL_PAR_ODD:
 		lcr_val |= UART_LCR_PEN;
 		break;
 	case SERIAL_PAR_EVEN:
 		lcr_val |= UART_LCR_PEN | UART_LCR_EPS;
 		break;
 	default:
 		return -ENOTSUPP; /* not supported in driver*/
 	}

 	serial_out(lcr_val, &com_port->lcr);
 	return 0;
 }

 static int ns16550_serial_getinfo(struct udevice *dev,
 				  struct serial_device_info *info)
 {
 	struct ns16550 *const com_port = dev_get_priv(dev);
 	struct ns16550_plat *plat = com_port->plat;

 	info->type = SERIAL_CHIP_16550_COMPATIBLE;
 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
 	info->addr_space = SERIAL_ADDRESS_SPACE_IO;
 #else
 	info->addr_space = SERIAL_ADDRESS_SPACE_MEMORY;
 #endif
 	info->addr = plat->base;
 	info->reg_width = plat->reg_width;
 	info->reg_shift = plat->reg_shift;
 	info->reg_offset = plat->reg_offset;
 	info->clock = plat->clock;

 	return 0;
 }

 static int ns16550_serial_assign_base(struct ns16550_plat *plat, fdt_addr_t base)
 {
 	if (base == FDT_ADDR_T_NONE)
 		return -EINVAL;

 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
 	plat->base = base;
 #else
 	plat->base = (unsigned long)map_physmem(base, 0, MAP_NOCACHE);
 #endif

 	return 0;
 }

 int ns16550_serial_probe(struct udevice *dev)
 {
 	struct ns16550_plat *plat = dev_get_plat(dev);
 	struct ns16550 *const com_port = dev_get_priv(dev);
 	struct reset_ctl_bulk reset_bulk;
 	fdt_addr_t addr;
 	int ret;

 	/*
 	 * If we are on PCI bus, either directly attached to a PCI root port,
 	 * or via a PCI bridge, assign plat->base before probing hardware.
 	 */
 	if (device_is_on_pci_bus(dev)) {
 		addr = devfdt_get_addr_pci(dev);
 		ret = ns16550_serial_assign_base(plat, addr);
 		if (ret)
 			return ret;
 	}

 	ret = reset_get_bulk(dev, &reset_bulk);
 	if (!ret)
 		reset_deassert_bulk(&reset_bulk);

 	com_port->plat = dev_get_plat(dev);
 	ns16550_init(com_port, -1);

 	return 0;
 }

 #if CONFIG_IS_ENABLED(OF_CONTROL)
 enum {
 	PORT_NS16550 = 0,
 	PORT_JZ4780,
 };
 #endif

 #if CONFIG_IS_ENABLED(OF_REAL)
 int ns16550_serial_of_to_plat(struct udevice *dev)
 {
 	struct ns16550_plat *plat = dev_get_plat(dev);
 	const u32 port_type = dev_get_driver_data(dev);
 	fdt_addr_t addr;
 	struct clk clk;
 	int err;

 	addr = dev_read_addr(dev);
 	err = ns16550_serial_assign_base(plat, addr);
 	if (err && !device_is_on_pci_bus(dev))
 		return err;

 	plat->reg_offset = dev_read_u32_default(dev, "reg-offset", 0);
 	plat->reg_shift = dev_read_u32_default(dev, "reg-shift", 0);
 	plat->reg_width = dev_read_u32_default(dev, "reg-io-width", 1);

 	err = clk_get_by_index(dev, 0, &clk);
 	if (!err) {
 		err = clk_get_rate(&clk);
 		if (!IS_ERR_VALUE(err))
 			plat->clock = err;
 	} else if (err != -ENOENT && err != -ENODEV && err != -ENOSYS) {
 		debug("ns16550 failed to get clock\n");
 		return err;
 	}

 	if (!plat->clock)
 		plat->clock = dev_read_u32_default(dev, "clock-frequency",
 						   CONFIG_SYS_NS16550_CLK);
 	if (!plat->clock)
 		plat->clock = CONFIG_SYS_NS16550_CLK;
 	if (!plat->clock) {
 		debug("ns16550 clock not defined\n");
 		return -EINVAL;
 	}

 	plat->fcr = UART_FCR_DEFVAL;
 	if (port_type == PORT_JZ4780)
 		plat->fcr |= UART_FCR_UME;

 	return 0;
 }
 #endif

 const struct dm_serial_ops ns16550_serial_ops = {
 	.putc = ns16550_serial_putc,
 	.pending = ns16550_serial_pending,
 	.getc = ns16550_serial_getc,
 	.setbrg = ns16550_serial_setbrg,
 	.setconfig = ns16550_serial_setconfig,
 	.getinfo = ns16550_serial_getinfo,
 };

 #if CONFIG_IS_ENABLED(OF_REAL)
 /*
  * Please consider existing compatible strings before adding a new
  * one to keep this table compact. Or you may add a generic "ns16550"
  * compatible string to your dts.
  */
 static const struct udevice_id ns16550_serial_ids[] = {
 	{ .compatible = "ns16550",		.data = PORT_NS16550 },
 	{ .compatible = "ns16550a",		.data = PORT_NS16550 },
 	{ .compatible = "ingenic,jz4780-uart",	.data = PORT_JZ4780  },
 	{ .compatible = "nvidia,tegra20-uart",	.data = PORT_NS16550 },
 	{ .compatible = "snps,dw-apb-uart",	.data = PORT_NS16550 },
 	{}
 };
 #endif /* OF_REAL */

 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)

 /* TODO(sjg@chromium.org): Integrate this into a macro like CONFIG_IS_ENABLED */
 #if !defined(CONFIG_TPL_BUILD) || defined(CONFIG_TPL_DM_SERIAL)
 U_BOOT_DRIVER(ns16550_serial) = {
 	.name	= "ns16550_serial",
 	.id	= UCLASS_SERIAL,
 #if CONFIG_IS_ENABLED(OF_REAL)
 	.of_match = ns16550_serial_ids,
 	.of_to_plat = ns16550_serial_of_to_plat,
 	.plat_auto	= sizeof(struct ns16550_plat),
 #endif
 	.priv_auto	= sizeof(struct ns16550),
 	.probe = ns16550_serial_probe,
 	.ops	= &ns16550_serial_ops,
 #if !CONFIG_IS_ENABLED(OF_CONTROL)
 	.flags	= DM_FLAG_PRE_RELOC,
 #endif
 };

 DM_DRIVER_ALIAS(ns16550_serial, rockchip_rk3328_uart)
 DM_DRIVER_ALIAS(ns16550_serial, rockchip_rk3368_uart)
 DM_DRIVER_ALIAS(ns16550_serial, ti_da830_uart)
 #endif
 #endif /* SERIAL_PRESENT */

 #endif /* CONFIG_DM_SERIAL */
	/*
	* COM1 NS16550 support
	* originally from linux source (arch/powerpc/boot/ns16550.c)
	* modified to use CONFIG_SYS_ISA_MEM and new defines
	*/

	#include <clock_legacy.h>
	#include <common.h>
	#include <clk.h>
	#include <dm.h>
	#include <errno.h>
	#include <log.h>
	#include <ns16550.h>
	#include <reset.h>
	#include <serial.h>
	#include <watchdog.h>
	#include <asm/global_data.h>
	#include <linux/err.h>
	#include <linux/types.h>
	#include <asm/io.h>

	DECLARE_GLOBAL_DATA_PTR;

	#define UART_LCRVAL UART_LCR_8N1 /* 8 data, 1 stop, no parity */
	#define UART_MCRVAL (UART_MCR_DTR \| \
	UART_MCR_RTS) /* RTS/DTR */

	#if !CONFIG_IS_ENABLED(DM_SERIAL)
	#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
	#define serial_out(x, y) outb(x, (ulong)y)
	#define serial_in(y) inb((ulong)y)
	#elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
	#define serial_out(x, y) out_be32(y, x)
	#define serial_in(y) in_be32(y)
	#elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
	#define serial_out(x, y) out_le32(y, x)
	#define serial_in(y) in_le32(y)
	#else
	#define serial_out(x, y) writeb(x, y)
	#define serial_in(y) readb(y)
	#endif
	#endif /* !CONFIG_DM_SERIAL */

	#if defined(CONFIG_ARCH_KEYSTONE)
	#define UART_REG_VAL_PWREMU_MGMT_UART_DISABLE 0
	#define UART_REG_VAL_PWREMU_MGMT_UART_ENABLE ((1 << 14) \| (1 << 13) \| (1 << 0))
	#undef UART_MCRVAL
	#ifdef CONFIG_SERIAL_HW_FLOW_CONTROL
	#define UART_MCRVAL (UART_MCR_RTS \| UART_MCR_AFE)
	#else
	#define UART_MCRVAL (UART_MCR_RTS)
	#endif
	#endif

	#ifndef CONFIG_SYS_NS16550_IER
	#define CONFIG_SYS_NS16550_IER 0x00
	#endif /* CONFIG_SYS_NS16550_IER */

	static inline void serial_out_shift(void *addr, int shift, int value)
	{
	#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
	outb(value, (ulong)addr);
	#elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_LITTLE_ENDIAN)
	out_le32(addr, value);
	#elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
	out_be32(addr, value);
	#elif defined(CONFIG_SYS_NS16550_MEM32)
	writel(value, addr);
	#elif defined(CONFIG_SYS_BIG_ENDIAN)
	writeb(value, addr + (1 << shift) - 1);
	#else
	writeb(value, addr);
	#endif
	}

	static inline int serial_in_shift(void *addr, int shift)
	{
	#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
	return inb((ulong)addr);
	#elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_LITTLE_ENDIAN)
	return in_le32(addr);
	#elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
	return in_be32(addr);
	#elif defined(CONFIG_SYS_NS16550_MEM32)
	return readl(addr);
	#elif defined(CONFIG_SYS_BIG_ENDIAN)
	return readb(addr + (1 << shift) - 1);
	#else
	return readb(addr);
	#endif
	}

	#if CONFIG_IS_ENABLED(DM_SERIAL)

	#ifndef CONFIG_SYS_NS16550_CLK
	#define CONFIG_SYS_NS16550_CLK 0
	#endif

	/*
	* Use this #ifdef for now since many platforms don't define in(), out(),
	* out_le32(), etc. but we don't have #defines to indicate this.
	*
	* TODO(sjg@chromium.org): Add CONFIG options to indicate what I/O is available
	* on a platform
	*/
	#ifdef CONFIG_NS16550_DYNAMIC
	static void serial_out_dynamic(struct ns16550_plat plat, u8 addr,
	int value)
	{
	if (plat->flags & NS16550_FLAG_IO) {
	outb(value, addr);
	} else if (plat->reg_width == 4) {
	if (plat->flags & NS16550_FLAG_ENDIAN) {
	if (plat->flags & NS16550_FLAG_BE)
	out_be32(addr, value);
	else
	out_le32(addr, value);
	} else {
	writel(value, addr);
	}
	} else if (plat->flags & NS16550_FLAG_BE) {
	writeb(value, addr + (1 << plat->reg_shift) - 1);
	} else {
	writeb(value, addr);
	}
	}

	static int serial_in_dynamic(struct ns16550_plat plat, u8 addr)
	{
	if (plat->flags & NS16550_FLAG_IO) {
	return inb(addr);
	} else if (plat->reg_width == 4) {
	if (plat->flags & NS16550_FLAG_ENDIAN) {
	if (plat->flags & NS16550_FLAG_BE)
	return in_be32(addr);
	else
	return in_le32(addr);
	} else {
	return readl(addr);
	}
	} else if (plat->flags & NS16550_FLAG_BE) {
	return readb(addr + (1 << plat->reg_shift) - 1);
	} else {
	return readb(addr);
	}
	}
	#else
	static inline void serial_out_dynamic(struct ns16550_plat plat, u8 addr,
	int value)
	{
	}

	static inline int serial_in_dynamic(struct ns16550_plat plat, u8 addr)
	{
	return 0;
	}

	#endif /* CONFIG_NS16550_DYNAMIC */

	static void ns16550_writeb(struct ns16550 *port, int offset, int value)
	{
	struct ns16550_plat *plat = port->plat;
	unsigned char *addr;

	offset *= 1 << plat->reg_shift;
	addr = (unsigned char *)plat->base + offset + plat->reg_offset;

	if (IS_ENABLED(CONFIG_NS16550_DYNAMIC))
	serial_out_dynamic(plat, addr, value);
	else
	serial_out_shift(addr, plat->reg_shift, value);
	}

	static int ns16550_readb(struct ns16550 *port, int offset)
	{
	struct ns16550_plat *plat = port->plat;
	unsigned char *addr;

	offset *= 1 << plat->reg_shift;
	addr = (unsigned char *)plat->base + offset + plat->reg_offset;

	if (IS_ENABLED(CONFIG_NS16550_DYNAMIC))
	return serial_in_dynamic(plat, addr);
	else
	return serial_in_shift(addr, plat->reg_shift);
	}

	static u32 ns16550_getfcr(struct ns16550 *port)
	{
	struct ns16550_plat *plat = port->plat;

	return plat->fcr;
	}

	/* We can clean these up once everything is moved to driver model */
	#define serial_out(value, addr) \
	ns16550_writeb(com_port, \
	(unsigned char )addr - (unsigned char )com_port, value)
	#define serial_in(addr) \
	ns16550_readb(com_port, \
	(unsigned char )addr - (unsigned char )com_port)
	#else
	static u32 ns16550_getfcr(struct ns16550 *port)
	{
	return UART_FCR_DEFVAL;
	}
	#endif

	int ns16550_calc_divisor(struct ns16550 *port, int clock, int baudrate)
	{
	const unsigned int mode_x_div = 16;

	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
	}

	static void ns16550_setbrg(struct ns16550 *com_port, int baud_divisor)
	{
	/* to keep serial format, read lcr before writing BKSE */
	int lcr_val = serial_in(&com_port->lcr) & ~UART_LCR_BKSE;

	serial_out(UART_LCR_BKSE \| lcr_val, &com_port->lcr);
	serial_out(baud_divisor & 0xff, &com_port->dll);
	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
	serial_out(lcr_val, &com_port->lcr);
	}

	void ns16550_init(struct ns16550 *com_port, int baud_divisor)
	{
	#if (defined(CONFIG_SPL_BUILD) && \
	(defined(CONFIG_OMAP34XX) \|\| defined(CONFIG_OMAP44XX)))
	/*
	* On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
	* before SPL starts only THRE bit is set. We have to empty the
	* transmitter before initialization starts.
	*/
	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT \| UART_LSR_THRE))
	== UART_LSR_THRE) {
	if (baud_divisor != -1)
	ns16550_setbrg(com_port, baud_divisor);
	else {
	// Re-use old baud rate divisor to flush transmit reg.
	const int dll = serial_in(&com_port->dll);
	const int dlm = serial_in(&com_port->dlm);
	const int divisor = dll \| (dlm << 8);
	ns16550_setbrg(com_port, divisor);
	}
	serial_out(0, &com_port->mdr1);
	}
	#endif

	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
	;

	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
	#if defined(CONFIG_ARCH_OMAP2PLUS) \|\| defined(CONFIG_OMAP_SERIAL)
	serial_out(0x7, &com_port->mdr1); /* mode select reset TL16C750*/
	#endif

	serial_out(UART_MCRVAL, &com_port->mcr);
	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
	/* initialize serial config to 8N1 before writing baudrate */
	serial_out(UART_LCRVAL, &com_port->lcr);
	if (baud_divisor != -1)
	ns16550_setbrg(com_port, baud_divisor);
	#if defined(CONFIG_ARCH_OMAP2PLUS) \|\| defined(CONFIG_SOC_DA8XX) \|\| \
	defined(CONFIG_OMAP_SERIAL)
	/* /16 is proper to hit 115200 with 48MHz */
	serial_out(0, &com_port->mdr1);
	#endif
	#if defined(CONFIG_ARCH_KEYSTONE)
	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
	#endif
	}

	#ifndef CONFIG_NS16550_MIN_FUNCTIONS
	void ns16550_reinit(struct ns16550 *com_port, int baud_divisor)
	{
	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
	ns16550_setbrg(com_port, 0);
	serial_out(UART_MCRVAL, &com_port->mcr);
	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
	ns16550_setbrg(com_port, baud_divisor);
	}
	#endif /* CONFIG_NS16550_MIN_FUNCTIONS */

	void ns16550_putc(struct ns16550 *com_port, char c)
	{
	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
	;
	serial_out(c, &com_port->thr);

	/*
	* Call watchdog_reset() upon newline. This is done here in putc
	* since the environment code uses a single puts() to print the complete
	* environment upon "printenv". So we can't put this watchdog call
	* in puts().
	*/
	if (c == '\n')
	WATCHDOG_RESET();
	}

	#ifndef CONFIG_NS16550_MIN_FUNCTIONS
	char ns16550_getc(struct ns16550 *com_port)
	{
	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
	#if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
	extern void usbtty_poll(void);
	usbtty_poll();
	#endif
	WATCHDOG_RESET();
	}
	return serial_in(&com_port->rbr);
	}

	int ns16550_tstc(struct ns16550 *com_port)
	{
	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
	}

	#endif /* CONFIG_NS16550_MIN_FUNCTIONS */

	#ifdef CONFIG_DEBUG_UART_NS16550

	#include <debug_uart.h>

	static inline void _debug_uart_init(void)
	{
	struct ns16550 com_port = (struct ns16550 )CONFIG_DEBUG_UART_BASE;
	int baud_divisor;

	/*
	* We copy the code from above because it is already horribly messy.
	* Trying to refactor to nicely remove the duplication doesn't seem
	* feasible. The better fix is to move all users of this driver to
	* driver model.
	*/
	baud_divisor = ns16550_calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
	CONFIG_BAUDRATE);
	serial_dout(&com_port->ier, CONFIG_SYS_NS16550_IER);
	serial_dout(&com_port->mcr, UART_MCRVAL);
	serial_dout(&com_port->fcr, UART_FCR_DEFVAL);

	serial_dout(&com_port->lcr, UART_LCR_BKSE \| UART_LCRVAL);
	serial_dout(&com_port->dll, baud_divisor & 0xff);
	serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
	serial_dout(&com_port->lcr, UART_LCRVAL);
	}

	static inline int NS16550_read_baud_divisor(struct ns16550 *com_port)
	{
	int ret;

	serial_dout(&com_port->lcr, UART_LCR_BKSE \| UART_LCRVAL);
	ret = serial_din(&com_port->dll) & 0xff;
	ret \|= (serial_din(&com_port->dlm) & 0xff) << 8;
	serial_dout(&com_port->lcr, UART_LCRVAL);

	return ret;
	}

	static inline void _debug_uart_putc(int ch)
	{
	struct ns16550 com_port = (struct ns16550 )CONFIG_DEBUG_UART_BASE;

	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE)) {
	#ifdef CONFIG_DEBUG_UART_NS16550_CHECK_ENABLED
	if (!NS16550_read_baud_divisor(com_port))
	return;
	#endif
	}
	serial_dout(&com_port->thr, ch);
	}

	DEBUG_UART_FUNCS

	#endif

	#if CONFIG_IS_ENABLED(DM_SERIAL)
	static int ns16550_serial_putc(struct udevice *dev, const char ch)
	{
	struct ns16550 *const com_port = dev_get_priv(dev);

	if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
	return -EAGAIN;
	serial_out(ch, &com_port->thr);

	/*
	* Call watchdog_reset() upon newline. This is done here in putc
	* since the environment code uses a single puts() to print the complete
	* environment upon "printenv". So we can't put this watchdog call
	* in puts().
	*/
	if (ch == '\n')
	WATCHDOG_RESET();

	return 0;
	}

	static int ns16550_serial_pending(struct udevice *dev, bool input)
	{
	struct ns16550 *const com_port = dev_get_priv(dev);

	if (input)
	return (serial_in(&com_port->lsr) & UART_LSR_DR) ? 1 : 0;
	else
	return (serial_in(&com_port->lsr) & UART_LSR_THRE) ? 0 : 1;
	}

	static int ns16550_serial_getc(struct udevice *dev)
	{
	struct ns16550 *const com_port = dev_get_priv(dev);

	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
	return -EAGAIN;

	return serial_in(&com_port->rbr);
	}

	static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
	{
	struct ns16550 *const com_port = dev_get_priv(dev);
	struct ns16550_plat *plat = com_port->plat;
	int clock_divisor;

	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);

	ns16550_setbrg(com_port, clock_divisor);

	return 0;
	}

	static int ns16550_serial_setconfig(struct udevice *dev, uint serial_config)
	{
	struct ns16550 *const com_port = dev_get_priv(dev);
	int lcr_val = UART_LCR_WLS_8;
	uint parity = SERIAL_GET_PARITY(serial_config);
	uint bits = SERIAL_GET_BITS(serial_config);
	uint stop = SERIAL_GET_STOP(serial_config);

	/*
	* only parity config is implemented, check if other serial settings
	* are the default one.
	*/
	if (bits != SERIAL_8_BITS \|\| stop != SERIAL_ONE_STOP)
	return -ENOTSUPP; /* not supported in driver*/

	switch (parity) {
	case SERIAL_PAR_NONE:
	/* no bits to add */
	break;
	case SERIAL_PAR_ODD:
	lcr_val \|= UART_LCR_PEN;
	break;
	case SERIAL_PAR_EVEN:
	lcr_val \|= UART_LCR_PEN \| UART_LCR_EPS;
	break;
	default:
	return -ENOTSUPP; /* not supported in driver*/
	}

	serial_out(lcr_val, &com_port->lcr);
	return 0;
	}

	static int ns16550_serial_getinfo(struct udevice *dev,
	struct serial_device_info *info)
	{
	struct ns16550 *const com_port = dev_get_priv(dev);
	struct ns16550_plat *plat = com_port->plat;

	info->type = SERIAL_CHIP_16550_COMPATIBLE;
	#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
	info->addr_space = SERIAL_ADDRESS_SPACE_IO;
	#else
	info->addr_space = SERIAL_ADDRESS_SPACE_MEMORY;
	#endif
	info->addr = plat->base;
	info->reg_width = plat->reg_width;
	info->reg_shift = plat->reg_shift;
	info->reg_offset = plat->reg_offset;
	info->clock = plat->clock;

	return 0;
	}

	static int ns16550_serial_assign_base(struct ns16550_plat *plat, fdt_addr_t base)
	{
	if (base == FDT_ADDR_T_NONE)
	return -EINVAL;

	#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
	plat->base = base;
	#else
	plat->base = (unsigned long)map_physmem(base, 0, MAP_NOCACHE);
	#endif

	return 0;
	}

	int ns16550_serial_probe(struct udevice *dev)
	{
	struct ns16550_plat *plat = dev_get_plat(dev);
	struct ns16550 *const com_port = dev_get_priv(dev);
	struct reset_ctl_bulk reset_bulk;
	fdt_addr_t addr;
	int ret;

	/*
	* If we are on PCI bus, either directly attached to a PCI root port,
	* or via a PCI bridge, assign plat->base before probing hardware.
	*/
	if (device_is_on_pci_bus(dev)) {
	addr = devfdt_get_addr_pci(dev);
	ret = ns16550_serial_assign_base(plat, addr);
	if (ret)
	return ret;
	}

	ret = reset_get_bulk(dev, &reset_bulk);
	if (!ret)
	reset_deassert_bulk(&reset_bulk);

	com_port->plat = dev_get_plat(dev);
	ns16550_init(com_port, -1);

	return 0;
	}

	#if CONFIG_IS_ENABLED(OF_CONTROL)
	enum {
	PORT_NS16550 = 0,
	PORT_JZ4780,
	};
	#endif

	#if CONFIG_IS_ENABLED(OF_REAL)
	int ns16550_serial_of_to_plat(struct udevice *dev)
	{
	struct ns16550_plat *plat = dev_get_plat(dev);
	const u32 port_type = dev_get_driver_data(dev);
	fdt_addr_t addr;
	struct clk clk;
	int err;

	addr = dev_read_addr(dev);
	err = ns16550_serial_assign_base(plat, addr);
	if (err && !device_is_on_pci_bus(dev))
	return err;

	plat->reg_offset = dev_read_u32_default(dev, "reg-offset", 0);
	plat->reg_shift = dev_read_u32_default(dev, "reg-shift", 0);
	plat->reg_width = dev_read_u32_default(dev, "reg-io-width", 1);

	err = clk_get_by_index(dev, 0, &clk);
	if (!err) {
	err = clk_get_rate(&clk);
	if (!IS_ERR_VALUE(err))
	plat->clock = err;
	} else if (err != -ENOENT && err != -ENODEV && err != -ENOSYS) {
	debug("ns16550 failed to get clock\n");
	return err;
	}

	if (!plat->clock)
	plat->clock = dev_read_u32_default(dev, "clock-frequency",
	CONFIG_SYS_NS16550_CLK);
	if (!plat->clock)
	plat->clock = CONFIG_SYS_NS16550_CLK;
	if (!plat->clock) {
	debug("ns16550 clock not defined\n");
	return -EINVAL;
	}

	plat->fcr = UART_FCR_DEFVAL;
	if (port_type == PORT_JZ4780)
	plat->fcr \|= UART_FCR_UME;

	return 0;
	}
	#endif

	const struct dm_serial_ops ns16550_serial_ops = {
	.putc = ns16550_serial_putc,
	.pending = ns16550_serial_pending,
	.getc = ns16550_serial_getc,
	.setbrg = ns16550_serial_setbrg,
	.setconfig = ns16550_serial_setconfig,
	.getinfo = ns16550_serial_getinfo,
	};

	#if CONFIG_IS_ENABLED(OF_REAL)
	/*
	* Please consider existing compatible strings before adding a new
	* one to keep this table compact. Or you may add a generic "ns16550"
	* compatible string to your dts.
	*/
	static const struct udevice_id ns16550_serial_ids[] = {
	{ .compatible = "ns16550", .data = PORT_NS16550 },
	{ .compatible = "ns16550a", .data = PORT_NS16550 },
	{ .compatible = "ingenic,jz4780-uart", .data = PORT_JZ4780 },
	{ .compatible = "nvidia,tegra20-uart", .data = PORT_NS16550 },
	{ .compatible = "snps,dw-apb-uart", .data = PORT_NS16550 },
	{}
	};
	#endif /* OF_REAL */

	#if CONFIG_IS_ENABLED(SERIAL_PRESENT)

	/* TODO(sjg@chromium.org): Integrate this into a macro like CONFIG_IS_ENABLED */
	#if !defined(CONFIG_TPL_BUILD) \|\| defined(CONFIG_TPL_DM_SERIAL)
	U_BOOT_DRIVER(ns16550_serial) = {
	.name = "ns16550_serial",
	.id = UCLASS_SERIAL,
	#if CONFIG_IS_ENABLED(OF_REAL)
	.of_match = ns16550_serial_ids,
	.of_to_plat = ns16550_serial_of_to_plat,
	.plat_auto = sizeof(struct ns16550_plat),
	#endif
	.priv_auto = sizeof(struct ns16550),
	.probe = ns16550_serial_probe,
	.ops = &ns16550_serial_ops,
	#if !CONFIG_IS_ENABLED(OF_CONTROL)
	.flags = DM_FLAG_PRE_RELOC,
	#endif
	};

	DM_DRIVER_ALIAS(ns16550_serial, rockchip_rk3328_uart)
	DM_DRIVER_ALIAS(ns16550_serial, rockchip_rk3368_uart)
	DM_DRIVER_ALIAS(ns16550_serial, ti_da830_uart)
	#endif
	#endif /* SERIAL_PRESENT */

	#endif /* CONFIG_DM_SERIAL */