xref: /openbmc/linux/drivers/tty/serial/8250/8250.h (revision fd5e9fccbd504c5179ab57ff695c610bca8809d6)

/* SPDX-License-Identifier: GPL-2.0+ */
/*
 *  Driver for 8250/16550-type serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *
 *  Copyright (C) 2001 Russell King.
 */

#include <linux/bits.h>
#include <linux/serial_8250.h>
#include <linux/serial_reg.h>
#include <linux/dmaengine.h>

#include "../serial_mctrl_gpio.h"

struct uart_8250_dma {
	int (*tx_dma)(struct uart_8250_port *p);
	int (*rx_dma)(struct uart_8250_port *p);
	void (*prepare_tx_dma)(struct uart_8250_port *p);
	void (*prepare_rx_dma)(struct uart_8250_port *p);

	/* Filter function */
	dma_filter_fn		fn;
	/* Parameter to the filter function */
	void			*rx_param;
	void			*tx_param;

	struct dma_slave_config	rxconf;
	struct dma_slave_config	txconf;

	struct dma_chan		*rxchan;
	struct dma_chan		*txchan;

	/* Device address base for DMA operations */
	phys_addr_t		rx_dma_addr;
	phys_addr_t		tx_dma_addr;

	/* DMA address of the buffer in memory */
	dma_addr_t		rx_addr;
	dma_addr_t		tx_addr;

	dma_cookie_t		rx_cookie;
	dma_cookie_t		tx_cookie;

	void			*rx_buf;

	size_t			rx_size;
	size_t			tx_size;

	unsigned char		tx_running;
	unsigned char		tx_err;
	unsigned char		rx_running;
};

struct old_serial_port {
	unsigned int uart;
	unsigned int baud_base;
	unsigned int port;
	unsigned int irq;
	upf_t        flags;
	unsigned char io_type;
	unsigned char __iomem *iomem_base;
	unsigned short iomem_reg_shift;
};

struct serial8250_config {
	const char	*name;
	unsigned short	fifo_size;
	unsigned short	tx_loadsz;
	unsigned char	fcr;
	unsigned char	rxtrig_bytes[UART_FCR_R_TRIG_MAX_STATE];
	unsigned int	flags;
};

#define UART_CAP_FIFO	BIT(8)	/* UART has FIFO */
#define UART_CAP_EFR	BIT(9)	/* UART has EFR */
#define UART_CAP_SLEEP	BIT(10)	/* UART has IER sleep */
#define UART_CAP_AFE	BIT(11)	/* MCR-based hw flow control */
#define UART_CAP_UUE	BIT(12)	/* UART needs IER bit 6 set (Xscale) */
#define UART_CAP_RTOIE	BIT(13)	/* UART needs IER bit 4 set (Xscale, Tegra) */
#define UART_CAP_HFIFO	BIT(14)	/* UART has a "hidden" FIFO */
#define UART_CAP_RPM	BIT(15)	/* Runtime PM is active while idle */
#define UART_CAP_IRDA	BIT(16)	/* UART supports IrDA line discipline */
#define UART_CAP_MINI	BIT(17)	/* Mini UART on BCM283X family lacks:
					 * STOP PARITY EPAR SPAR WLEN5 WLEN6
					 */
#define UART_CAP_NOTEMT	BIT(18)	/* UART without interrupt on TEMT available */

#define UART_BUG_QUOT	BIT(0)	/* UART has buggy quot LSB */
#define UART_BUG_TXEN	BIT(1)	/* UART has buggy TX IIR status */
#define UART_BUG_NOMSR	BIT(2)	/* UART has buggy MSR status bits (Au1x00) */
#define UART_BUG_THRE	BIT(3)	/* UART has buggy THRE reassertion */
#define UART_BUG_TXRACE	BIT(5)	/* UART Tx fails to set remote DR */


#ifdef CONFIG_SERIAL_8250_SHARE_IRQ
#define SERIAL8250_SHARE_IRQS 1
#else
#define SERIAL8250_SHARE_IRQS 0
#endif

#define SERIAL8250_PORT_FLAGS(_base, _irq, _flags)		\
	{							\
		.iobase		= _base,			\
		.irq		= _irq,				\
		.uartclk	= 1843200,			\
		.iotype		= UPIO_PORT,			\
		.flags		= UPF_BOOT_AUTOCONF | (_flags),	\
	}

#define SERIAL8250_PORT(_base, _irq) SERIAL8250_PORT_FLAGS(_base, _irq, 0)


static inline int serial_in(struct uart_8250_port *up, int offset)
{
	return up->port.serial_in(&up->port, offset);
}

static inline void serial_out(struct uart_8250_port *up, int offset, int value)
{
	up->port.serial_out(&up->port, offset, value);
}

/**
 *	serial_lsr_in - Read LSR register and preserve flags across reads
 *	@up:	uart 8250 port
 *
 *	Read LSR register and handle saving non-preserved flags across reads.
 *	The flags that are not preserved across reads are stored into
 *	up->lsr_saved_flags.
 *
 *	Returns LSR value or'ed with the preserved flags (if any).
 */
static inline u16 serial_lsr_in(struct uart_8250_port *up)
{
	u16 lsr = up->lsr_saved_flags;

	lsr |= serial_in(up, UART_LSR);
	up->lsr_saved_flags = lsr & up->lsr_save_mask;

	return lsr;
}

/*
 * For the 16C950
 */
static void serial_icr_write(struct uart_8250_port *up, int offset, int value)
{
	serial_out(up, UART_SCR, offset);
	serial_out(up, UART_ICR, value);
}

static unsigned int __maybe_unused serial_icr_read(struct uart_8250_port *up,
						   int offset)
{
	unsigned int value;

	serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD);
	serial_out(up, UART_SCR, offset);
	value = serial_in(up, UART_ICR);
	serial_icr_write(up, UART_ACR, up->acr);

	return value;
}

void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p);

static inline u32 serial_dl_read(struct uart_8250_port *up)
{
	return up->dl_read(up);
}

static inline void serial_dl_write(struct uart_8250_port *up, u32 value)
{
	up->dl_write(up, value);
}

static inline bool serial8250_set_THRI(struct uart_8250_port *up)
{
	/* Port locked to synchronize UART_IER access against the console. */
	lockdep_assert_held_once(&up->port.lock);

	if (up->ier & UART_IER_THRI)
		return false;
	up->ier |= UART_IER_THRI;
	serial_out(up, UART_IER, up->ier);
	return true;
}

static inline bool serial8250_clear_THRI(struct uart_8250_port *up)
{
	/* Port locked to synchronize UART_IER access against the console. */
	lockdep_assert_held_once(&up->port.lock);

	if (!(up->ier & UART_IER_THRI))
		return false;
	up->ier &= ~UART_IER_THRI;
	serial_out(up, UART_IER, up->ier);
	return true;
}

struct uart_8250_port *serial8250_get_port(int line);

void serial8250_rpm_get(struct uart_8250_port *p);
void serial8250_rpm_put(struct uart_8250_port *p);

void serial8250_rpm_get_tx(struct uart_8250_port *p);
void serial8250_rpm_put_tx(struct uart_8250_port *p);

int serial8250_em485_config(struct uart_port *port, struct ktermios *termios,
			    struct serial_rs485 *rs485);
void serial8250_em485_start_tx(struct uart_8250_port *p);
void serial8250_em485_stop_tx(struct uart_8250_port *p);
void serial8250_em485_destroy(struct uart_8250_port *p);
extern struct serial_rs485 serial8250_em485_supported;

/* MCR <-> TIOCM conversion */
static inline int serial8250_TIOCM_to_MCR(int tiocm)
{
	int mcr = 0;

	if (tiocm & TIOCM_RTS)
		mcr |= UART_MCR_RTS;
	if (tiocm & TIOCM_DTR)
		mcr |= UART_MCR_DTR;
	if (tiocm & TIOCM_OUT1)
		mcr |= UART_MCR_OUT1;
	if (tiocm & TIOCM_OUT2)
		mcr |= UART_MCR_OUT2;
	if (tiocm & TIOCM_LOOP)
		mcr |= UART_MCR_LOOP;

	return mcr;
}

static inline int serial8250_MCR_to_TIOCM(int mcr)
{
	int tiocm = 0;

	if (mcr & UART_MCR_RTS)
		tiocm |= TIOCM_RTS;
	if (mcr & UART_MCR_DTR)
		tiocm |= TIOCM_DTR;
	if (mcr & UART_MCR_OUT1)
		tiocm |= TIOCM_OUT1;
	if (mcr & UART_MCR_OUT2)
		tiocm |= TIOCM_OUT2;
	if (mcr & UART_MCR_LOOP)
		tiocm |= TIOCM_LOOP;

	return tiocm;
}

/* MSR <-> TIOCM conversion */
static inline int serial8250_MSR_to_TIOCM(int msr)
{
	int tiocm = 0;

	if (msr & UART_MSR_DCD)
		tiocm |= TIOCM_CAR;
	if (msr & UART_MSR_RI)
		tiocm |= TIOCM_RNG;
	if (msr & UART_MSR_DSR)
		tiocm |= TIOCM_DSR;
	if (msr & UART_MSR_CTS)
		tiocm |= TIOCM_CTS;

	return tiocm;
}

static inline void serial8250_out_MCR(struct uart_8250_port *up, int value)
{
	serial_out(up, UART_MCR, value);

	if (up->gpios)
		mctrl_gpio_set(up->gpios, serial8250_MCR_to_TIOCM(value));
}

static inline int serial8250_in_MCR(struct uart_8250_port *up)
{
	int mctrl;

	mctrl = serial_in(up, UART_MCR);

	if (up->gpios) {
		unsigned int mctrl_gpio = 0;

		mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio);
		mctrl |= serial8250_TIOCM_to_MCR(mctrl_gpio);
	}

	return mctrl;
}

bool alpha_jensen(void);
void alpha_jensen_set_mctrl(struct uart_port *port, unsigned int mctrl);

#ifdef CONFIG_SERIAL_8250_PNP
int serial8250_pnp_init(void);
void serial8250_pnp_exit(void);
#else
static inline int serial8250_pnp_init(void) { return 0; }
static inline void serial8250_pnp_exit(void) { }
#endif

#ifdef CONFIG_SERIAL_8250_FINTEK
int fintek_8250_probe(struct uart_8250_port *uart);
#else
static inline int fintek_8250_probe(struct uart_8250_port *uart) { return 0; }
#endif

#ifdef CONFIG_ARCH_OMAP1
#include <linux/soc/ti/omap1-soc.h>
static inline int is_omap1_8250(struct uart_8250_port *pt)
{
	int res;

	switch (pt->port.mapbase) {
	case OMAP1_UART1_BASE:
	case OMAP1_UART2_BASE:
	case OMAP1_UART3_BASE:
		res = 1;
		break;
	default:
		res = 0;
		break;
	}

	return res;
}

static inline int is_omap1510_8250(struct uart_8250_port *pt)
{
	if (!cpu_is_omap1510())
		return 0;

	return is_omap1_8250(pt);
}
#else
static inline int is_omap1_8250(struct uart_8250_port *pt)
{
	return 0;
}
static inline int is_omap1510_8250(struct uart_8250_port *pt)
{
	return 0;
}
#endif

#ifdef CONFIG_SERIAL_8250_DMA
extern int serial8250_tx_dma(struct uart_8250_port *);
extern void serial8250_tx_dma_flush(struct uart_8250_port *);
extern int serial8250_rx_dma(struct uart_8250_port *);
extern void serial8250_rx_dma_flush(struct uart_8250_port *);
extern int serial8250_request_dma(struct uart_8250_port *);
extern void serial8250_release_dma(struct uart_8250_port *);

static inline void serial8250_do_prepare_tx_dma(struct uart_8250_port *p)
{
	struct uart_8250_dma *dma = p->dma;

	if (dma->prepare_tx_dma)
		dma->prepare_tx_dma(p);
}

static inline void serial8250_do_prepare_rx_dma(struct uart_8250_port *p)
{
	struct uart_8250_dma *dma = p->dma;

	if (dma->prepare_rx_dma)
		dma->prepare_rx_dma(p);
}

static inline bool serial8250_tx_dma_running(struct uart_8250_port *p)
{
	struct uart_8250_dma *dma = p->dma;

	return dma && dma->tx_running;
}
#else
static inline int serial8250_tx_dma(struct uart_8250_port *p)
{
	return -1;
}
static inline void serial8250_tx_dma_flush(struct uart_8250_port *p) { }
static inline int serial8250_rx_dma(struct uart_8250_port *p)
{
	return -1;
}
static inline void serial8250_rx_dma_flush(struct uart_8250_port *p) { }
static inline int serial8250_request_dma(struct uart_8250_port *p)
{
	return -1;
}
static inline void serial8250_release_dma(struct uart_8250_port *p) { }

static inline bool serial8250_tx_dma_running(struct uart_8250_port *p)
{
	return false;
}
#endif

static inline int ns16550a_goto_highspeed(struct uart_8250_port *up)
{
	unsigned char status;

	status = serial_in(up, 0x04); /* EXCR2 */
#define PRESL(x) ((x) & 0x30)
	if (PRESL(status) == 0x10) {
		/* already in high speed mode */
		return 0;
	} else {
		status &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */
		status |= 0x10;  /* 1.625 divisor for baud_base --> 921600 */
		serial_out(up, 0x04, status);
	}
	return 1;
}

static inline int serial_index(struct uart_port *port)
{
	return port->minor - 64;
}