// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for the PSC of the Freescale MPC52xx PSCs configured as UARTs.
 *
 * FIXME According to the usermanual the status bits in the status register
 * are only updated when the peripherals access the FIFO and not when the
 * CPU access them. So since we use this bits to know when we stop writing
 * and reading, they may not be updated in-time and a race condition may
 * exists. But I haven't be able to prove this and I don't care. But if
 * any problem arises, it might worth checking. The TX/RX FIFO Stats
 * registers should be used in addition.
 * Update: Actually, they seem updated ... At least the bits we use.
 *
 *
 * Maintainer : Sylvain Munaut <tnt@246tNt.com>
 *
 * Some of the code has been inspired/copied from the 2.4 code written
 * by Dale Farnsworth <dfarnsworth@mvista.com>.
 *
 * Copyright (C) 2008 Freescale Semiconductor Inc.
 *                    John Rigby <jrigby@gmail.com>
 * Added support for MPC5121
 * Copyright (C) 2006 Secret Lab Technologies Ltd.
 *                    Grant Likely <grant.likely@secretlab.ca>
 * Copyright (C) 2004-2006 Sylvain Munaut <tnt@246tNt.com>
 * Copyright (C) 2003 MontaVista, Software, Inc.
 */

#undef DEBUG

#include <linux/device.h>
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/clk.h>

#include <asm/mpc52xx.h>
#include <asm/mpc52xx_psc.h>

#include <linux/serial_core.h>


/* We've been assigned a range on the "Low-density serial ports" major */
#define SERIAL_PSC_MAJOR        204
#define SERIAL_PSC_MINOR        148


#define ISR_PASS_LIMIT 256      /* Max number of iteration in the interrupt */


static struct uart_port mpc52xx_uart_ports[MPC52xx_PSC_MAXNUM];
        /* Rem: - We use the read_status_mask as a shadow of
         *        psc->mpc52xx_psc_imr
         *      - It's important that is array is all zero on start as we
         *        use it to know if it's initialized or not ! If it's not sure
         *        it's cleared, then a memset(...,0,...) should be added to
         *        the console_init
         */

/* lookup table for matching device nodes to index numbers */
static struct device_node *mpc52xx_uart_nodes[MPC52xx_PSC_MAXNUM];

static void mpc52xx_uart_of_enumerate(void);


#define PSC(port) ((struct mpc52xx_psc __iomem *)((port)->membase))


/* Forward declaration of the interruption handling routine */
static irqreturn_t mpc52xx_uart_int(int irq, void *dev_id);
static irqreturn_t mpc5xxx_uart_process_int(struct uart_port *port);

/* ======================================================================== */
/* PSC fifo operations for isolating differences between 52xx and 512x      */
/* ======================================================================== */

struct psc_ops {
        void            (*fifo_init)(struct uart_port *port);
        unsigned int    (*raw_rx_rdy)(struct uart_port *port);
        unsigned int    (*raw_tx_rdy)(struct uart_port *port);
        unsigned int    (*rx_rdy)(struct uart_port *port);
        unsigned int    (*tx_rdy)(struct uart_port *port);
        unsigned int    (*tx_empty)(struct uart_port *port);
        void            (*stop_rx)(struct uart_port *port);
        void            (*start_tx)(struct uart_port *port);
        void            (*stop_tx)(struct uart_port *port);
        void            (*rx_clr_irq)(struct uart_port *port);
        void            (*tx_clr_irq)(struct uart_port *port);
        void            (*write_char)(struct uart_port *port, unsigned char c);
        unsigned char   (*read_char)(struct uart_port *port);
        void            (*cw_disable_ints)(struct uart_port *port);
        void            (*cw_restore_ints)(struct uart_port *port);
        unsigned int    (*set_baudrate)(struct uart_port *port,
                                        struct ktermios *new,
                                        const struct ktermios *old);
        int             (*clock_alloc)(struct uart_port *port);
        void            (*clock_relse)(struct uart_port *port);
        int             (*clock)(struct uart_port *port, int enable);
        int             (*fifoc_init)(void);
        void            (*fifoc_uninit)(void);
        void            (*get_irq)(struct uart_port *, struct device_node *);
        irqreturn_t     (*handle_irq)(struct uart_port *port);
        u16             (*get_status)(struct uart_port *port);
        u8              (*get_ipcr)(struct uart_port *port);
        void            (*command)(struct uart_port *port, u8 cmd);
        void            (*set_mode)(struct uart_port *port, u8 mr1, u8 mr2);
        void            (*set_rts)(struct uart_port *port, int state);
        void            (*enable_ms)(struct uart_port *port);
        void            (*set_sicr)(struct uart_port *port, u32 val);
        void            (*set_imr)(struct uart_port *port, u16 val);
        u8              (*get_mr1)(struct uart_port *port);
};

/* setting the prescaler and divisor reg is common for all chips */
static inline void mpc52xx_set_divisor(struct mpc52xx_psc __iomem *psc,
                                       u16 prescaler, unsigned int divisor)
{
        /* select prescaler */
        out_be16(&psc->mpc52xx_psc_clock_select, prescaler);
        out_8(&psc->ctur, divisor >> 8);
        out_8(&psc->ctlr, divisor & 0xff);
}

static u16 mpc52xx_psc_get_status(struct uart_port *port)
{
        return in_be16(&PSC(port)->mpc52xx_psc_status);
}

static u8 mpc52xx_psc_get_ipcr(struct uart_port *port)
{
        return in_8(&PSC(port)->mpc52xx_psc_ipcr);
}

static void mpc52xx_psc_command(struct uart_port *port, u8 cmd)
{
        out_8(&PSC(port)->command, cmd);
}

static void mpc52xx_psc_set_mode(struct uart_port *port, u8 mr1, u8 mr2)
{
        out_8(&PSC(port)->command, MPC52xx_PSC_SEL_MODE_REG_1);
        out_8(&PSC(port)->mode, mr1);
        out_8(&PSC(port)->mode, mr2);
}

static void mpc52xx_psc_set_rts(struct uart_port *port, int state)
{
        if (state)
                out_8(&PSC(port)->op1, MPC52xx_PSC_OP_RTS);
        else
                out_8(&PSC(port)->op0, MPC52xx_PSC_OP_RTS);
}

static void mpc52xx_psc_enable_ms(struct uart_port *port)
{
        struct mpc52xx_psc __iomem *psc = PSC(port);

        /* clear D_*-bits by reading them */
        in_8(&psc->mpc52xx_psc_ipcr);
        /* enable CTS and DCD as IPC interrupts */
        out_8(&psc->mpc52xx_psc_acr, MPC52xx_PSC_IEC_CTS | MPC52xx_PSC_IEC_DCD);

        port->read_status_mask |= MPC52xx_PSC_IMR_IPC;
        out_be16(&psc->mpc52xx_psc_imr, port->read_status_mask);
}

static void mpc52xx_psc_set_sicr(struct uart_port *port, u32 val)
{
        out_be32(&PSC(port)->sicr, val);
}

static void mpc52xx_psc_set_imr(struct uart_port *port, u16 val)
{
        out_be16(&PSC(port)->mpc52xx_psc_imr, val);
}

static u8 mpc52xx_psc_get_mr1(struct uart_port *port)
{
        out_8(&PSC(port)->command, MPC52xx_PSC_SEL_MODE_REG_1);
        return in_8(&PSC(port)->mode);
}

#ifdef CONFIG_PPC_MPC52xx
#define FIFO_52xx(port) ((struct mpc52xx_psc_fifo __iomem *)(PSC(port)+1))
static void mpc52xx_psc_fifo_init(struct uart_port *port)
{
        struct mpc52xx_psc __iomem *psc = PSC(port);
        struct mpc52xx_psc_fifo __iomem *fifo = FIFO_52xx(port);

        out_8(&fifo->rfcntl, 0x00);
        out_be16(&fifo->rfalarm, 0x1ff);
        out_8(&fifo->tfcntl, 0x07);
        out_be16(&fifo->tfalarm, 0x80);

        port->read_status_mask |= MPC52xx_PSC_IMR_RXRDY | MPC52xx_PSC_IMR_TXRDY;
        out_be16(&psc->mpc52xx_psc_imr, port->read_status_mask);
}

static unsigned int mpc52xx_psc_raw_rx_rdy(struct uart_port *port)
{
        return in_be16(&PSC(port)->mpc52xx_psc_status)
            & MPC52xx_PSC_SR_RXRDY;
}

static unsigned int mpc52xx_psc_raw_tx_rdy(struct uart_port *port)
{
        return in_be16(&PSC(port)->mpc52xx_psc_status)
            & MPC52xx_PSC_SR_TXRDY;
}


static unsigned int mpc52xx_psc_rx_rdy(struct uart_port *port)
{
        return in_be16(&PSC(port)->mpc52xx_psc_isr)
            & port->read_status_mask
            & MPC52xx_PSC_IMR_RXRDY;
}

static unsigned int mpc52xx_psc_tx_rdy(struct uart_port *port)
{
        return in_be16(&PSC(port)->mpc52xx_psc_isr)
            & port->read_status_mask
            & MPC52xx_PSC_IMR_TXRDY;
}

static unsigned int mpc52xx_psc_tx_empty(struct uart_port *port)
{
        u16 sts = in_be16(&PSC(port)->mpc52xx_psc_status);

        return (sts & MPC52xx_PSC_SR_TXEMP) ? TIOCSER_TEMT : 0;
}

static void mpc52xx_psc_start_tx(struct uart_port *port)
{
        port->read_status_mask |= MPC52xx_PSC_IMR_TXRDY;
        out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
}

static void mpc52xx_psc_stop_tx(struct uart_port *port)
{
        port->read_status_mask &= ~MPC52xx_PSC_IMR_TXRDY;
        out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
}

static void mpc52xx_psc_stop_rx(struct uart_port *port)
{
        port->read_status_mask &= ~MPC52xx_PSC_IMR_RXRDY;
        out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
}

static void mpc52xx_psc_rx_clr_irq(struct uart_port *port)
{
}

static void mpc52xx_psc_tx_clr_irq(struct uart_port *port)
{
}

static void mpc52xx_psc_write_char(struct uart_port *port, unsigned char c)
{
        out_8(&PSC(port)->mpc52xx_psc_buffer_8, c);
}

static unsigned char mpc52xx_psc_read_char(struct uart_port *port)
{
        return in_8(&PSC(port)->mpc52xx_psc_buffer_8);
}

static void mpc52xx_psc_cw_disable_ints(struct uart_port *port)
{
        out_be16(&PSC(port)->mpc52xx_psc_imr, 0);
}

static void mpc52xx_psc_cw_restore_ints(struct uart_port *port)
{
        out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
}

static unsigned int mpc5200_psc_set_baudrate(struct uart_port *port,
                                             struct ktermios *new,
                                             const struct ktermios *old)
{
        unsigned int baud;
        unsigned int divisor;

        /* The 5200 has a fixed /32 prescaler, uartclk contains the ipb freq */
        baud = uart_get_baud_rate(port, new, old,
                                  port->uartclk / (32 * 0xffff) + 1,
                                  port->uartclk / 32);
        divisor = (port->uartclk + 16 * baud) / (32 * baud);

        /* enable the /32 prescaler and set the divisor */
        mpc52xx_set_divisor(PSC(port), 0xdd00, divisor);
        return baud;
}

static unsigned int mpc5200b_psc_set_baudrate(struct uart_port *port,
                                              struct ktermios *new,
                                              const struct ktermios *old)
{
        unsigned int baud;
        unsigned int divisor;
        u16 prescaler;

        /* The 5200B has a selectable /4 or /32 prescaler, uartclk contains the
         * ipb freq */
        baud = uart_get_baud_rate(port, new, old,
                                  port->uartclk / (32 * 0xffff) + 1,
                                  port->uartclk / 4);
        divisor = (port->uartclk + 2 * baud) / (4 * baud);

        /* select the proper prescaler and set the divisor
         * prefer high prescaler for more tolerance on low baudrates */
        if (divisor > 0xffff || baud <= 115200) {
                divisor = (divisor + 4) / 8;
                prescaler = 0xdd00; /* /32 */
        } else
                prescaler = 0xff00; /* /4 */
        mpc52xx_set_divisor(PSC(port), prescaler, divisor);
        return baud;
}

static void mpc52xx_psc_get_irq(struct uart_port *port, struct device_node *np)
{
        port->irqflags = 0;
        port->irq = irq_of_parse_and_map(np, 0);
}

/* 52xx specific interrupt handler. The caller holds the port lock */
static irqreturn_t mpc52xx_psc_handle_irq(struct uart_port *port)
{
        return mpc5xxx_uart_process_int(port);
}

static const struct psc_ops mpc52xx_psc_ops = {
        .fifo_init = mpc52xx_psc_fifo_init,
        .raw_rx_rdy = mpc52xx_psc_raw_rx_rdy,
        .raw_tx_rdy = mpc52xx_psc_raw_tx_rdy,
        .rx_rdy = mpc52xx_psc_rx_rdy,
        .tx_rdy = mpc52xx_psc_tx_rdy,
        .tx_empty = mpc52xx_psc_tx_empty,
        .stop_rx = mpc52xx_psc_stop_rx,
        .start_tx = mpc52xx_psc_start_tx,
        .stop_tx = mpc52xx_psc_stop_tx,
        .rx_clr_irq = mpc52xx_psc_rx_clr_irq,
        .tx_clr_irq = mpc52xx_psc_tx_clr_irq,
        .write_char = mpc52xx_psc_write_char,
        .read_char = mpc52xx_psc_read_char,
        .cw_disable_ints = mpc52xx_psc_cw_disable_ints,
        .cw_restore_ints = mpc52xx_psc_cw_restore_ints,
        .set_baudrate = mpc5200_psc_set_baudrate,
        .get_irq = mpc52xx_psc_get_irq,
        .handle_irq = mpc52xx_psc_handle_irq,
        .get_status = mpc52xx_psc_get_status,
        .get_ipcr = mpc52xx_psc_get_ipcr,
        .command = mpc52xx_psc_command,
        .set_mode = mpc52xx_psc_set_mode,
        .set_rts = mpc52xx_psc_set_rts,
        .enable_ms = mpc52xx_psc_enable_ms,
        .set_sicr = mpc52xx_psc_set_sicr,
        .set_imr = mpc52xx_psc_set_imr,
        .get_mr1 = mpc52xx_psc_get_mr1,
};

static const struct psc_ops mpc5200b_psc_ops = {
        .fifo_init = mpc52xx_psc_fifo_init,
        .raw_rx_rdy = mpc52xx_psc_raw_rx_rdy,
        .raw_tx_rdy = mpc52xx_psc_raw_tx_rdy,
        .rx_rdy = mpc52xx_psc_rx_rdy,
        .tx_rdy = mpc52xx_psc_tx_rdy,
        .tx_empty = mpc52xx_psc_tx_empty,
        .stop_rx = mpc52xx_psc_stop_rx,
        .start_tx = mpc52xx_psc_start_tx,
        .stop_tx = mpc52xx_psc_stop_tx,
        .rx_clr_irq = mpc52xx_psc_rx_clr_irq,
        .tx_clr_irq = mpc52xx_psc_tx_clr_irq,
        .write_char = mpc52xx_psc_write_char,
        .read_char = mpc52xx_psc_read_char,
        .cw_disable_ints = mpc52xx_psc_cw_disable_ints,
        .cw_restore_ints = mpc52xx_psc_cw_restore_ints,
        .set_baudrate = mpc5200b_psc_set_baudrate,
        .get_irq = mpc52xx_psc_get_irq,
        .handle_irq = mpc52xx_psc_handle_irq,
        .get_status = mpc52xx_psc_get_status,
        .get_ipcr = mpc52xx_psc_get_ipcr,
        .command = mpc52xx_psc_command,
        .set_mode = mpc52xx_psc_set_mode,
        .set_rts = mpc52xx_psc_set_rts,
        .enable_ms = mpc52xx_psc_enable_ms,
        .set_sicr = mpc52xx_psc_set_sicr,
        .set_imr = mpc52xx_psc_set_imr,
        .get_mr1 = mpc52xx_psc_get_mr1,
};

#endif /* CONFIG_PPC_MPC52xx */

#ifdef CONFIG_PPC_MPC512x
#define FIFO_512x(port) ((struct mpc512x_psc_fifo __iomem *)(PSC(port)+1))

/* PSC FIFO Controller for mpc512x */
struct psc_fifoc {
        u32 fifoc_cmd;
        u32 fifoc_int;
        u32 fifoc_dma;
        u32 fifoc_axe;
        u32 fifoc_debug;
};

static struct psc_fifoc __iomem *psc_fifoc;
static unsigned int psc_fifoc_irq;
static struct clk *psc_fifoc_clk;

static void mpc512x_psc_fifo_init(struct uart_port *port)
{
        /* /32 prescaler */
        out_be16(&PSC(port)->mpc52xx_psc_clock_select, 0xdd00);

        out_be32(&FIFO_512x(port)->txcmd, MPC512x_PSC_FIFO_RESET_SLICE);
        out_be32(&FIFO_512x(port)->txcmd, MPC512x_PSC_FIFO_ENABLE_SLICE);
        out_be32(&FIFO_512x(port)->txalarm, 1);
        out_be32(&FIFO_512x(port)->tximr, 0);

        out_be32(&FIFO_512x(port)->rxcmd, MPC512x_PSC_FIFO_RESET_SLICE);
        out_be32(&FIFO_512x(port)->rxcmd, MPC512x_PSC_FIFO_ENABLE_SLICE);
        out_be32(&FIFO_512x(port)->rxalarm, 1);
        out_be32(&FIFO_512x(port)->rximr, 0);

        out_be32(&FIFO_512x(port)->tximr, MPC512x_PSC_FIFO_ALARM);
        out_be32(&FIFO_512x(port)->rximr, MPC512x_PSC_FIFO_ALARM);
}

static unsigned int mpc512x_psc_raw_rx_rdy(struct uart_port *port)
{
        return !(in_be32(&FIFO_512x(port)->rxsr) & MPC512x_PSC_FIFO_EMPTY);
}

static unsigned int mpc512x_psc_raw_tx_rdy(struct uart_port *port)
{
        return !(in_be32(&FIFO_512x(port)->txsr) & MPC512x_PSC_FIFO_FULL);
}

static unsigned int mpc512x_psc_rx_rdy(struct uart_port *port)
{
        return in_be32(&FIFO_512x(port)->rxsr)
            & in_be32(&FIFO_512x(port)->rximr)
            & MPC512x_PSC_FIFO_ALARM;
}

static unsigned int mpc512x_psc_tx_rdy(struct uart_port *port)
{
        return in_be32(&FIFO_512x(port)->txsr)
            & in_be32(&FIFO_512x(port)->tximr)
            & MPC512x_PSC_FIFO_ALARM;
}

static unsigned int mpc512x_psc_tx_empty(struct uart_port *port)
{
        return in_be32(&FIFO_512x(port)->txsr)
            & MPC512x_PSC_FIFO_EMPTY;
}

static void mpc512x_psc_stop_rx(struct uart_port *port)
{
        unsigned long rx_fifo_imr;

        rx_fifo_imr = in_be32(&FIFO_512x(port)->rximr);
        rx_fifo_imr &= ~MPC512x_PSC_FIFO_ALARM;
        out_be32(&FIFO_512x(port)->rximr, rx_fifo_imr);
}

static void mpc512x_psc_start_tx(struct uart_port *port)
{
        unsigned long tx_fifo_imr;

        tx_fifo_imr = in_be32(&FIFO_512x(port)->tximr);
        tx_fifo_imr |= MPC512x_PSC_FIFO_ALARM;
        out_be32(&FIFO_512x(port)->tximr, tx_fifo_imr);
}

static void mpc512x_psc_stop_tx(struct uart_port *port)
{
        unsigned long tx_fifo_imr;

        tx_fifo_imr = in_be32(&FIFO_512x(port)->tximr);
        tx_fifo_imr &= ~MPC512x_PSC_FIFO_ALARM;
        out_be32(&FIFO_512x(port)->tximr, tx_fifo_imr);
}

static void mpc512x_psc_rx_clr_irq(struct uart_port *port)
{
        out_be32(&FIFO_512x(port)->rxisr, in_be32(&FIFO_512x(port)->rxisr));
}

static void mpc512x_psc_tx_clr_irq(struct uart_port *port)
{
        out_be32(&FIFO_512x(port)->txisr, in_be32(&FIFO_512x(port)->txisr));
}

static void mpc512x_psc_write_char(struct uart_port *port, unsigned char c)
{
        out_8(&FIFO_512x(port)->txdata_8, c);
}

static unsigned char mpc512x_psc_read_char(struct uart_port *port)
{
        return in_8(&FIFO_512x(port)->rxdata_8);
}

static void mpc512x_psc_cw_disable_ints(struct uart_port *port)
{
        port->read_status_mask =
                in_be32(&FIFO_512x(port)->tximr) << 16 |
                in_be32(&FIFO_512x(port)->rximr);
        out_be32(&FIFO_512x(port)->tximr, 0);
        out_be32(&FIFO_512x(port)->rximr, 0);
}

static void mpc512x_psc_cw_restore_ints(struct uart_port *port)
{
        out_be32(&FIFO_512x(port)->tximr,
                (port->read_status_mask >> 16) & 0x7f);
        out_be32(&FIFO_512x(port)->rximr, port->read_status_mask & 0x7f);
}

static unsigned int mpc512x_psc_set_baudrate(struct uart_port *port,
                                             struct ktermios *new,
                                             const struct ktermios *old)
{
        unsigned int baud;
        unsigned int divisor;

        /*
         * The "MPC5121e Microcontroller Reference Manual, Rev. 3" says on
         * pg. 30-10 that the chip supports a /32 and a /10 prescaler.
         * Furthermore, it states that "After reset, the prescaler by 10
         * for the UART mode is selected", but the reset register value is
         * 0x0000 which means a /32 prescaler. This is wrong.
         *
         * In reality using /32 prescaler doesn't work, as it is not supported!
         * Use /16 or /10 prescaler, see "MPC5121e Hardware Design Guide",
         * Chapter 4.1 PSC in UART Mode.
         * Calculate with a /16 prescaler here.
         */

        /* uartclk contains the ips freq */
        baud = uart_get_baud_rate(port, new, old,
                                  port->uartclk / (16 * 0xffff) + 1,
                                  port->uartclk / 16);
        divisor = (port->uartclk + 8 * baud) / (16 * baud);

        /* enable the /16 prescaler and set the divisor */
        mpc52xx_set_divisor(PSC(port), 0xdd00, divisor);
        return baud;
}

/* Init PSC FIFO Controller */
static int __init mpc512x_psc_fifoc_init(void)
{
        int err;
        struct device_node *np;
        struct clk *clk;

        /* default error code, potentially overwritten by clock calls */
        err = -ENODEV;

        np = of_find_compatible_node(NULL, NULL,
                                     "fsl,mpc5121-psc-fifo");
        if (!np) {
                pr_err("%s: Can't find FIFOC node\n", __func__);
                goto out_err;
        }

        clk = of_clk_get(np, 0);
        if (IS_ERR(clk)) {
                /* backwards compat with device trees that lack clock specs */
                clk = clk_get_sys(np->name, "ipg");
        }
        if (IS_ERR(clk)) {
                pr_err("%s: Can't lookup FIFO clock\n", __func__);
                err = PTR_ERR(clk);
                goto out_ofnode_put;
        }
        if (clk_prepare_enable(clk)) {
                pr_err("%s: Can't enable FIFO clock\n", __func__);
                clk_put(clk);
                goto out_ofnode_put;
        }
        psc_fifoc_clk = clk;

        psc_fifoc = of_iomap(np, 0);
        if (!psc_fifoc) {
                pr_err("%s: Can't map FIFOC\n", __func__);
                goto out_clk_disable;
        }

        psc_fifoc_irq = irq_of_parse_and_map(np, 0);
        if (psc_fifoc_irq == 0) {
                pr_err("%s: Can't get FIFOC irq\n", __func__);
                goto out_unmap;
        }

        of_node_put(np);
        return 0;

out_unmap:
        iounmap(psc_fifoc);
out_clk_disable:
        clk_disable_unprepare(psc_fifoc_clk);
        clk_put(psc_fifoc_clk);
out_ofnode_put:
        of_node_put(np);
out_err:
        return err;
}

static void __exit mpc512x_psc_fifoc_uninit(void)
{
        iounmap(psc_fifoc);

        /* disable the clock, errors are not fatal */
        if (psc_fifoc_clk) {
                clk_disable_unprepare(psc_fifoc_clk);
                clk_put(psc_fifoc_clk);
                psc_fifoc_clk = NULL;
        }
}

/* 512x specific interrupt handler. The caller holds the port lock */
static irqreturn_t mpc512x_psc_handle_irq(struct uart_port *port)
{
        unsigned long fifoc_int;
        int psc_num;

        /* Read pending PSC FIFOC interrupts */
        fifoc_int = in_be32(&psc_fifoc->fifoc_int);

        /* Check if it is an interrupt for this port */
        psc_num = (port->mapbase & 0xf00) >> 8;
        if (test_bit(psc_num, &fifoc_int) ||
            test_bit(psc_num + 16, &fifoc_int))
                return mpc5xxx_uart_process_int(port);

        return IRQ_NONE;
}

static struct clk *psc_mclk_clk[MPC52xx_PSC_MAXNUM];
static struct clk *psc_ipg_clk[MPC52xx_PSC_MAXNUM];

/* called from within the .request_port() callback (allocation) */
static int mpc512x_psc_alloc_clock(struct uart_port *port)
{
        int psc_num;
        struct clk *clk;
        int err;

        psc_num = (port->mapbase & 0xf00) >> 8;

        clk = devm_clk_get(port->dev, "mclk");
        if (IS_ERR(clk)) {
                dev_err(port->dev, "Failed to get MCLK!\n");
                err = PTR_ERR(clk);
                goto out_err;
        }
        err = clk_prepare_enable(clk);
        if (err) {
                dev_err(port->dev, "Failed to enable MCLK!\n");
                goto out_err;
        }
        psc_mclk_clk[psc_num] = clk;

        clk = devm_clk_get(port->dev, "ipg");
        if (IS_ERR(clk)) {
                dev_err(port->dev, "Failed to get IPG clock!\n");
                err = PTR_ERR(clk);
                goto out_err;
        }
        err = clk_prepare_enable(clk);
        if (err) {
                dev_err(port->dev, "Failed to enable IPG clock!\n");
                goto out_err;
        }
        psc_ipg_clk[psc_num] = clk;

        return 0;

out_err:
        if (psc_mclk_clk[psc_num]) {
                clk_disable_unprepare(psc_mclk_clk[psc_num]);
                psc_mclk_clk[psc_num] = NULL;
        }
        if (psc_ipg_clk[psc_num]) {
                clk_disable_unprepare(psc_ipg_clk[psc_num]);
                psc_ipg_clk[psc_num] = NULL;
        }
        return err;
}

/* called from within the .release_port() callback (release) */
static void mpc512x_psc_relse_clock(struct uart_port *port)
{
        int psc_num;
        struct clk *clk;

        psc_num = (port->mapbase & 0xf00) >> 8;
        clk = psc_mclk_clk[psc_num];
        if (clk) {
                clk_disable_unprepare(clk);
                psc_mclk_clk[psc_num] = NULL;
        }
        if (psc_ipg_clk[psc_num]) {
                clk_disable_unprepare(psc_ipg_clk[psc_num]);
                psc_ipg_clk[psc_num] = NULL;
        }
}

/* implementation of the .clock() callback (enable/disable) */
static int mpc512x_psc_endis_clock(struct uart_port *port, int enable)
{
        int psc_num;
        struct clk *psc_clk;
        int ret;

        if (uart_console(port))
                return 0;

        psc_num = (port->mapbase & 0xf00) >> 8;
        psc_clk = psc_mclk_clk[psc_num];
        if (!psc_clk) {
                dev_err(port->dev, "Failed to get PSC clock entry!\n");
                return -ENODEV;
        }

        dev_dbg(port->dev, "mclk %sable\n", enable ? "en" : "dis");
        if (enable) {
                ret = clk_enable(psc_clk);
                if (ret)
                        dev_err(port->dev, "Failed to enable MCLK!\n");
                return ret;
        } else {
                clk_disable(psc_clk);
                return 0;
        }
}

static void mpc512x_psc_get_irq(struct uart_port *port, struct device_node *np)
{
        port->irqflags = IRQF_SHARED;
        port->irq = psc_fifoc_irq;
}

#define PSC_5125(port) ((struct mpc5125_psc __iomem *)((port)->membase))
#define FIFO_5125(port) ((struct mpc512x_psc_fifo __iomem *)(PSC_5125(port)+1))

static void mpc5125_psc_fifo_init(struct uart_port *port)
{
        /* /32 prescaler */
        out_8(&PSC_5125(port)->mpc52xx_psc_clock_select, 0xdd);

        out_be32(&FIFO_5125(port)->txcmd, MPC512x_PSC_FIFO_RESET_SLICE);
        out_be32(&FIFO_5125(port)->txcmd, MPC512x_PSC_FIFO_ENABLE_SLICE);
        out_be32(&FIFO_5125(port)->txalarm, 1);
        out_be32(&FIFO_5125(port)->tximr, 0);

        out_be32(&FIFO_5125(port)->rxcmd, MPC512x_PSC_FIFO_RESET_SLICE);
        out_be32(&FIFO_5125(port)->rxcmd, MPC512x_PSC_FIFO_ENABLE_SLICE);
        out_be32(&FIFO_5125(port)->rxalarm, 1);
        out_be32(&FIFO_5125(port)->rximr, 0);

        out_be32(&FIFO_5125(port)->tximr, MPC512x_PSC_FIFO_ALARM);
        out_be32(&FIFO_5125(port)->rximr, MPC512x_PSC_FIFO_ALARM);
}

static unsigned int mpc5125_psc_raw_rx_rdy(struct uart_port *port)
{
        return !(in_be32(&FIFO_5125(port)->rxsr) & MPC512x_PSC_FIFO_EMPTY);
}

static unsigned int mpc5125_psc_raw_tx_rdy(struct uart_port *port)
{
        return !(in_be32(&FIFO_5125(port)->txsr) & MPC512x_PSC_FIFO_FULL);
}

static unsigned int mpc5125_psc_rx_rdy(struct uart_port *port)
{
        return in_be32(&FIFO_5125(port)->rxsr) &
               in_be32(&FIFO_5125(port)->rximr) & MPC512x_PSC_FIFO_ALARM;
}

static unsigned int mpc5125_psc_tx_rdy(struct uart_port *port)
{
        return in_be32(&FIFO_5125(port)->txsr) &
               in_be32(&FIFO_5125(port)->tximr) & MPC512x_PSC_FIFO_ALARM;
}

static unsigned int mpc5125_psc_tx_empty(struct uart_port *port)
{
        return in_be32(&FIFO_5125(port)->txsr) & MPC512x_PSC_FIFO_EMPTY;
}

static void mpc5125_psc_stop_rx(struct uart_port *port)
{
        unsigned long rx_fifo_imr;

        rx_fifo_imr = in_be32(&FIFO_5125(port)->rximr);
        rx_fifo_imr &= ~MPC512x_PSC_FIFO_ALARM;
        out_be32(&FIFO_5125(port)->rximr, rx_fifo_imr);
}

static void mpc5125_psc_start_tx(struct uart_port *port)
{
        unsigned long tx_fifo_imr;

        tx_fifo_imr = in_be32(&FIFO_5125(port)->tximr);
        tx_fifo_imr |= MPC512x_PSC_FIFO_ALARM;
        out_be32(&FIFO_5125(port)->tximr, tx_fifo_imr);
}

static void mpc5125_psc_stop_tx(struct uart_port *port)
{
        unsigned long tx_fifo_imr;

        tx_fifo_imr = in_be32(&FIFO_5125(port)->tximr);
        tx_fifo_imr &= ~MPC512x_PSC_FIFO_ALARM;
        out_be32(&FIFO_5125(port)->tximr, tx_fifo_imr);
}

static void mpc5125_psc_rx_clr_irq(struct uart_port *port)
{
        out_be32(&FIFO_5125(port)->rxisr, in_be32(&FIFO_5125(port)->rxisr));
}

static void mpc5125_psc_tx_clr_irq(struct uart_port *port)
{
        out_be32(&FIFO_5125(port)->txisr, in_be32(&FIFO_5125(port)->txisr));
}

static void mpc5125_psc_write_char(struct uart_port *port, unsigned char c)
{
        out_8(&FIFO_5125(port)->txdata_8, c);
}

static unsigned char mpc5125_psc_read_char(struct uart_port *port)
{
        return in_8(&FIFO_5125(port)->rxdata_8);
}

static void mpc5125_psc_cw_disable_ints(struct uart_port *port)
{
        port->read_status_mask =
                in_be32(&FIFO_5125(port)->tximr) << 16 |
                in_be32(&FIFO_5125(port)->rximr);
        out_be32(&FIFO_5125(port)->tximr, 0);
        out_be32(&FIFO_5125(port)->rximr, 0);
}

static void mpc5125_psc_cw_restore_ints(struct uart_port *port)
{
        out_be32(&FIFO_5125(port)->tximr,
                (port->read_status_mask >> 16) & 0x7f);
        out_be32(&FIFO_5125(port)->rximr, port->read_status_mask & 0x7f);
}

static inline void mpc5125_set_divisor(struct mpc5125_psc __iomem *psc,
                u8 prescaler, unsigned int divisor)
{
        /* select prescaler */
        out_8(&psc->mpc52xx_psc_clock_select, prescaler);
        out_8(&psc->ctur, divisor >> 8);
        out_8(&psc->ctlr, divisor & 0xff);
}

static unsigned int mpc5125_psc_set_baudrate(struct uart_port *port,
                                             struct ktermios *new,
                                             const struct ktermios *old)
{
        unsigned int baud;
        unsigned int divisor;

        /*
         * Calculate with a /16 prescaler here.
         */

        /* uartclk contains the ips freq */
        baud = uart_get_baud_rate(port, new, old,
                                  port->uartclk / (16 * 0xffff) + 1,
                                  port->uartclk / 16);
        divisor = (port->uartclk + 8 * baud) / (16 * baud);

        /* enable the /16 prescaler and set the divisor */
        mpc5125_set_divisor(PSC_5125(port), 0xdd, divisor);
        return baud;
}

/*
 * MPC5125 have compatible PSC FIFO Controller.
 * Special init not needed.
 */
static u16 mpc5125_psc_get_status(struct uart_port *port)
{
        return in_be16(&PSC_5125(port)->mpc52xx_psc_status);
}

static u8 mpc5125_psc_get_ipcr(struct uart_port *port)
{
        return in_8(&PSC_5125(port)->mpc52xx_psc_ipcr);
}

static void mpc5125_psc_command(struct uart_port *port, u8 cmd)
{
        out_8(&PSC_5125(port)->command, cmd);
}

static void mpc5125_psc_set_mode(struct uart_port *port, u8 mr1, u8 mr2)
{
        out_8(&PSC_5125(port)->mr1, mr1);
        out_8(&PSC_5125(port)->mr2, mr2);
}

static void mpc5125_psc_set_rts(struct uart_port *port, int state)
{
        if (state & TIOCM_RTS)
                out_8(&PSC_5125(port)->op1, MPC52xx_PSC_OP_RTS);
        else
                out_8(&PSC_5125(port)->op0, MPC52xx_PSC_OP_RTS);
}

static void mpc5125_psc_enable_ms(struct uart_port *port)
{
        struct mpc5125_psc __iomem *psc = PSC_5125(port);

        /* clear D_*-bits by reading them */
        in_8(&psc->mpc52xx_psc_ipcr);
        /* enable CTS and DCD as IPC interrupts */
        out_8(&psc->mpc52xx_psc_acr, MPC52xx_PSC_IEC_CTS | MPC52xx_PSC_IEC_DCD);

        port->read_status_mask |= MPC52xx_PSC_IMR_IPC;
        out_be16(&psc->mpc52xx_psc_imr, port->read_status_mask);
}

static void mpc5125_psc_set_sicr(struct uart_port *port, u32 val)
{
        out_be32(&PSC_5125(port)->sicr, val);
}

static void mpc5125_psc_set_imr(struct uart_port *port, u16 val)
{
        out_be16(&PSC_5125(port)->mpc52xx_psc_imr, val);
}

static u8 mpc5125_psc_get_mr1(struct uart_port *port)
{
        return in_8(&PSC_5125(port)->mr1);
}

static const struct psc_ops mpc5125_psc_ops = {
        .fifo_init = mpc5125_psc_fifo_init,
        .raw_rx_rdy = mpc5125_psc_raw_rx_rdy,
        .raw_tx_rdy = mpc5125_psc_raw_tx_rdy,
        .rx_rdy = mpc5125_psc_rx_rdy,
        .tx_rdy = mpc5125_psc_tx_rdy,
        .tx_empty = mpc5125_psc_tx_empty,
        .stop_rx = mpc5125_psc_stop_rx,
        .start_tx = mpc5125_psc_start_tx,
        .stop_tx = mpc5125_psc_stop_tx,
        .rx_clr_irq = mpc5125_psc_rx_clr_irq,
        .tx_clr_irq = mpc5125_psc_tx_clr_irq,
        .write_char = mpc5125_psc_write_char,
        .read_char = mpc5125_psc_read_char,
        .cw_disable_ints = mpc5125_psc_cw_disable_ints,
        .cw_restore_ints = mpc5125_psc_cw_restore_ints,
        .set_baudrate = mpc5125_psc_set_baudrate,
        .clock_alloc = mpc512x_psc_alloc_clock,
        .clock_relse = mpc512x_psc_relse_clock,
        .clock = mpc512x_psc_endis_clock,
        .fifoc_init = mpc512x_psc_fifoc_init,
        .fifoc_uninit = mpc512x_psc_fifoc_uninit,
        .get_irq = mpc512x_psc_get_irq,
        .handle_irq = mpc512x_psc_handle_irq,
        .get_status = mpc5125_psc_get_status,
        .get_ipcr = mpc5125_psc_get_ipcr,
        .command = mpc5125_psc_command,
        .set_mode = mpc5125_psc_set_mode,
        .set_rts = mpc5125_psc_set_rts,
        .enable_ms = mpc5125_psc_enable_ms,
        .set_sicr = mpc5125_psc_set_sicr,
        .set_imr = mpc5125_psc_set_imr,
        .get_mr1 = mpc5125_psc_get_mr1,
};

static const struct psc_ops mpc512x_psc_ops = {
        .fifo_init = mpc512x_psc_fifo_init,
        .raw_rx_rdy = mpc512x_psc_raw_rx_rdy,
        .raw_tx_rdy = mpc512x_psc_raw_tx_rdy,
        .rx_rdy = mpc512x_psc_rx_rdy,
        .tx_rdy = mpc512x_psc_tx_rdy,
        .tx_empty = mpc512x_psc_tx_empty,
        .stop_rx = mpc512x_psc_stop_rx,
        .start_tx = mpc512x_psc_start_tx,
        .stop_tx = mpc512x_psc_stop_tx,
        .rx_clr_irq = mpc512x_psc_rx_clr_irq,
        .tx_clr_irq = mpc512x_psc_tx_clr_irq,
        .write_char = mpc512x_psc_write_char,
        .read_char = mpc512x_psc_read_char,
        .cw_disable_ints = mpc512x_psc_cw_disable_ints,
        .cw_restore_ints = mpc512x_psc_cw_restore_ints,
        .set_baudrate = mpc512x_psc_set_baudrate,
        .clock_alloc = mpc512x_psc_alloc_clock,
        .clock_relse = mpc512x_psc_relse_clock,
        .clock = mpc512x_psc_endis_clock,
        .fifoc_init = mpc512x_psc_fifoc_init,
        .fifoc_uninit = mpc512x_psc_fifoc_uninit,
        .get_irq = mpc512x_psc_get_irq,
        .handle_irq = mpc512x_psc_handle_irq,
        .get_status = mpc52xx_psc_get_status,
        .get_ipcr = mpc52xx_psc_get_ipcr,
        .command = mpc52xx_psc_command,
        .set_mode = mpc52xx_psc_set_mode,
        .set_rts = mpc52xx_psc_set_rts,
        .enable_ms = mpc52xx_psc_enable_ms,
        .set_sicr = mpc52xx_psc_set_sicr,
        .set_imr = mpc52xx_psc_set_imr,
        .get_mr1 = mpc52xx_psc_get_mr1,
};
#endif /* CONFIG_PPC_MPC512x */


static const struct psc_ops *psc_ops;

/* ======================================================================== */
/* UART operations                                                          */
/* ======================================================================== */

static unsigned int
mpc52xx_uart_tx_empty(struct uart_port *port)
{
        return psc_ops->tx_empty(port) ? TIOCSER_TEMT : 0;
}

static void
mpc52xx_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        psc_ops->set_rts(port, mctrl & TIOCM_RTS);
}

static unsigned int
mpc52xx_uart_get_mctrl(struct uart_port *port)
{
        unsigned int ret = TIOCM_DSR;
        u8 status = psc_ops->get_ipcr(port);

        if (!(status & MPC52xx_PSC_CTS))
                ret |= TIOCM_CTS;
        if (!(status & MPC52xx_PSC_DCD))
                ret |= TIOCM_CAR;

        return ret;
}

static void
mpc52xx_uart_stop_tx(struct uart_port *port)
{
        /* port->lock taken by caller */
        psc_ops->stop_tx(port);
}

static void
mpc52xx_uart_start_tx(struct uart_port *port)
{
        /* port->lock taken by caller */
        psc_ops->start_tx(port);
}

static void
mpc52xx_uart_stop_rx(struct uart_port *port)
{
        /* port->lock taken by caller */
        psc_ops->stop_rx(port);
}

static void
mpc52xx_uart_enable_ms(struct uart_port *port)
{
        psc_ops->enable_ms(port);
}

static void
mpc52xx_uart_break_ctl(struct uart_port *port, int ctl)
{
        unsigned long flags;
        uart_port_lock_irqsave(port, &flags);

        if (ctl == -1)
                psc_ops->command(port, MPC52xx_PSC_START_BRK);
        else
                psc_ops->command(port, MPC52xx_PSC_STOP_BRK);

        uart_port_unlock_irqrestore(port, flags);
}

static int
mpc52xx_uart_startup(struct uart_port *port)
{
        int ret;

        if (psc_ops->clock) {
                ret = psc_ops->clock(port, 1);
                if (ret)
                        return ret;
        }

        /* Request IRQ */
        ret = request_irq(port->irq, mpc52xx_uart_int,
                          port->irqflags, "mpc52xx_psc_uart", port);
        if (ret)
                return ret;

        /* Reset/activate the port, clear and enable interrupts */
        psc_ops->command(port, MPC52xx_PSC_RST_RX);
        psc_ops->command(port, MPC52xx_PSC_RST_TX);

        /*
         * According to Freescale's support the RST_TX command can produce a
         * spike on the TX pin. So they recommend to delay "for one character".
         * One millisecond should be enough for everyone.
         */
        msleep(1);

        psc_ops->set_sicr(port, 0);     /* UART mode DCD ignored */

        psc_ops->fifo_init(port);

        psc_ops->command(port, MPC52xx_PSC_TX_ENABLE);
        psc_ops->command(port, MPC52xx_PSC_RX_ENABLE);

        return 0;
}

static void
mpc52xx_uart_shutdown(struct uart_port *port)
{
        /* Shut down the port.  Leave TX active if on a console port */
        psc_ops->command(port, MPC52xx_PSC_RST_RX);
        if (!uart_console(port))
                psc_ops->command(port, MPC52xx_PSC_RST_TX);

        port->read_status_mask = 0;
        psc_ops->set_imr(port, port->read_status_mask);

        if (psc_ops->clock)
                psc_ops->clock(port, 0);

        /* Disable interrupt */
        psc_ops->cw_disable_ints(port);

        /* Release interrupt */
        free_irq(port->irq, port);
}

static void
mpc52xx_uart_set_termios(struct uart_port *port, struct ktermios *new,
                         const struct ktermios *old)
{
        unsigned long flags;
        unsigned char mr1, mr2;
        unsigned int j;
        unsigned int baud;

        /* Prepare what we're gonna write */
        mr1 = 0;

        switch (new->c_cflag & CSIZE) {
        case CS5:       mr1 |= MPC52xx_PSC_MODE_5_BITS;
                break;
        case CS6:       mr1 |= MPC52xx_PSC_MODE_6_BITS;
                break;
        case CS7:       mr1 |= MPC52xx_PSC_MODE_7_BITS;
                break;
        case CS8:
        default:        mr1 |= MPC52xx_PSC_MODE_8_BITS;
        }

        if (new->c_cflag & PARENB) {
                if (new->c_cflag & CMSPAR)
                        mr1 |= MPC52xx_PSC_MODE_PARFORCE;

                /* With CMSPAR, PARODD also means high parity (same as termios) */
                mr1 |= (new->c_cflag & PARODD) ?
                        MPC52xx_PSC_MODE_PARODD : MPC52xx_PSC_MODE_PAREVEN;
        } else {
                mr1 |= MPC52xx_PSC_MODE_PARNONE;
        }

        mr2 = 0;

        if (new->c_cflag & CSTOPB)
                mr2 |= MPC52xx_PSC_MODE_TWO_STOP;
        else
                mr2 |= ((new->c_cflag & CSIZE) == CS5) ?
                        MPC52xx_PSC_MODE_ONE_STOP_5_BITS :
                        MPC52xx_PSC_MODE_ONE_STOP;

        if (new->c_cflag & CRTSCTS) {
                mr1 |= MPC52xx_PSC_MODE_RXRTS;
                mr2 |= MPC52xx_PSC_MODE_TXCTS;
        }

        /* Get the lock */
        uart_port_lock_irqsave(port, &flags);

        /* Do our best to flush TX & RX, so we don't lose anything */
        /* But we don't wait indefinitely ! */
        j = 5000000;    /* Maximum wait */
        /* FIXME Can't receive chars since set_termios might be called at early
         * boot for the console, all stuff is not yet ready to receive at that
         * time and that just makes the kernel oops */
        /* while (j-- && mpc52xx_uart_int_rx_chars(port)); */
        while (!mpc52xx_uart_tx_empty(port) && --j)
                udelay(1);

        if (!j)
                printk(KERN_ERR "mpc52xx_uart.c: "
                        "Unable to flush RX & TX fifos in-time in set_termios."
                        "Some chars may have been lost.\n");

        /* Reset the TX & RX */
        psc_ops->command(port, MPC52xx_PSC_RST_RX);
        psc_ops->command(port, MPC52xx_PSC_RST_TX);

        /* Send new mode settings */
        psc_ops->set_mode(port, mr1, mr2);
        baud = psc_ops->set_baudrate(port, new, old);

        /* Update the per-port timeout */
        uart_update_timeout(port, new->c_cflag, baud);

        if (UART_ENABLE_MS(port, new->c_cflag))
                mpc52xx_uart_enable_ms(port);

        /* Reenable TX & RX */
        psc_ops->command(port, MPC52xx_PSC_TX_ENABLE);
        psc_ops->command(port, MPC52xx_PSC_RX_ENABLE);

        /* We're all set, release the lock */
        uart_port_unlock_irqrestore(port, flags);
}

static const char *
mpc52xx_uart_type(struct uart_port *port)
{
        /*
         * We keep using PORT_MPC52xx for historic reasons although it applies
         * for MPC512x, too, but print "MPC5xxx" to not irritate users
         */
        return port->type == PORT_MPC52xx ? "MPC5xxx PSC" : NULL;
}

static void
mpc52xx_uart_release_port(struct uart_port *port)
{
        if (psc_ops->clock_relse)
                psc_ops->clock_relse(port);

        /* remapped by us ? */
        if (port->flags & UPF_IOREMAP) {
                iounmap(port->membase);
                port->membase = NULL;
        }

        release_mem_region(port->mapbase, sizeof(struct mpc52xx_psc));
}

static int
mpc52xx_uart_request_port(struct uart_port *port)
{
        int err;

        if (port->flags & UPF_IOREMAP) /* Need to remap ? */
                port->membase = ioremap(port->mapbase,
                                        sizeof(struct mpc52xx_psc));

        if (!port->membase)
                return -EINVAL;

        err = request_mem_region(port->mapbase, sizeof(struct mpc52xx_psc),
                        "mpc52xx_psc_uart") != NULL ? 0 : -EBUSY;

        if (err)
                goto out_membase;

        if (psc_ops->clock_alloc) {
                err = psc_ops->clock_alloc(port);
                if (err)
                        goto out_mapregion;
        }

        return 0;

out_mapregion:
        release_mem_region(port->mapbase, sizeof(struct mpc52xx_psc));
out_membase:
        if (port->flags & UPF_IOREMAP) {
                iounmap(port->membase);
                port->membase = NULL;
        }
        return err;
}

static void
mpc52xx_uart_config_port(struct uart_port *port, int flags)
{
        if ((flags & UART_CONFIG_TYPE)
                && (mpc52xx_uart_request_port(port) == 0))
                port->type = PORT_MPC52xx;
}

static int
mpc52xx_uart_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        if (ser->type != PORT_UNKNOWN && ser->type != PORT_MPC52xx)
                return -EINVAL;

        if ((ser->irq != port->irq) ||
            (ser->io_type != UPIO_MEM) ||
            (ser->baud_base != port->uartclk)  ||
            (ser->iomem_base != (void *)port->mapbase) ||
            (ser->hub6 != 0))
                return -EINVAL;

        return 0;
}


static const struct uart_ops mpc52xx_uart_ops = {
        .tx_empty       = mpc52xx_uart_tx_empty,
        .set_mctrl      = mpc52xx_uart_set_mctrl,
        .get_mctrl      = mpc52xx_uart_get_mctrl,
        .stop_tx        = mpc52xx_uart_stop_tx,
        .start_tx       = mpc52xx_uart_start_tx,
        .stop_rx        = mpc52xx_uart_stop_rx,
        .enable_ms      = mpc52xx_uart_enable_ms,
        .break_ctl      = mpc52xx_uart_break_ctl,
        .startup        = mpc52xx_uart_startup,
        .shutdown       = mpc52xx_uart_shutdown,
        .set_termios    = mpc52xx_uart_set_termios,
        .type           = mpc52xx_uart_type,
        .release_port   = mpc52xx_uart_release_port,
        .request_port   = mpc52xx_uart_request_port,
        .config_port    = mpc52xx_uart_config_port,
        .verify_port    = mpc52xx_uart_verify_port
};


/* ======================================================================== */
/* Interrupt handling                                                       */
/* ======================================================================== */

static inline bool
mpc52xx_uart_int_rx_chars(struct uart_port *port)
{
        struct tty_port *tport = &port->state->port;
        unsigned char ch, flag;
        unsigned short status;

        /* While we can read, do so ! */
        while (psc_ops->raw_rx_rdy(port)) {
                /* Get the char */
                ch = psc_ops->read_char(port);

                /* Handle sysreq char */
                if (uart_handle_sysrq_char(port, ch))
                        continue;

                /* Store it */

                flag = TTY_NORMAL;
                port->icount.rx++;

                status = psc_ops->get_status(port);

                if (status & (MPC52xx_PSC_SR_PE |
                              MPC52xx_PSC_SR_FE |
                              MPC52xx_PSC_SR_RB)) {

                        if (status & MPC52xx_PSC_SR_RB) {
                                flag = TTY_BREAK;
                                uart_handle_break(port);
                                port->icount.brk++;
                        } else if (status & MPC52xx_PSC_SR_PE) {
                                flag = TTY_PARITY;
                                port->icount.parity++;
                        }
                        else if (status & MPC52xx_PSC_SR_FE) {
                                flag = TTY_FRAME;
                                port->icount.frame++;
                        }

                        /* Clear error condition */
                        psc_ops->command(port, MPC52xx_PSC_RST_ERR_STAT);

                }
                tty_insert_flip_char(tport, ch, flag);
                if (status & MPC52xx_PSC_SR_OE) {
                        /*
                         * Overrun is special, since it's
                         * reported immediately, and doesn't
                         * affect the current character
                         */
                        tty_insert_flip_char(tport, 0, TTY_OVERRUN);
                        port->icount.overrun++;
                }
        }

        tty_flip_buffer_push(tport);

        return psc_ops->raw_rx_rdy(port);
}

static inline bool
mpc52xx_uart_int_tx_chars(struct uart_port *port)
{
        u8 ch;

        return uart_port_tx(port, ch,
                psc_ops->raw_tx_rdy(port),
                psc_ops->write_char(port, ch));
}

static irqreturn_t
mpc5xxx_uart_process_int(struct uart_port *port)
{
        unsigned long pass = ISR_PASS_LIMIT;
        bool keepgoing;
        u8 status;

        /* While we have stuff to do, we continue */
        do {
                /* If we don't find anything to do, we stop */
                keepgoing = false;

                psc_ops->rx_clr_irq(port);
                if (psc_ops->rx_rdy(port))
                        keepgoing |= mpc52xx_uart_int_rx_chars(port);

                psc_ops->tx_clr_irq(port);
                if (psc_ops->tx_rdy(port))
                        keepgoing |= mpc52xx_uart_int_tx_chars(port);

                status = psc_ops->get_ipcr(port);
                if (status & MPC52xx_PSC_D_DCD)
                        uart_handle_dcd_change(port, !(status & MPC52xx_PSC_DCD));

                if (status & MPC52xx_PSC_D_CTS)
                        uart_handle_cts_change(port, !(status & MPC52xx_PSC_CTS));

                /* Limit number of iteration */
                if (!(--pass))
                        keepgoing = false;

        } while (keepgoing);

        return IRQ_HANDLED;
}

static irqreturn_t
mpc52xx_uart_int(int irq, void *dev_id)
{
        struct uart_port *port = dev_id;
        irqreturn_t ret;

        uart_port_lock(port);

        ret = psc_ops->handle_irq(port);

        uart_port_unlock(port);

        return ret;
}

/* ======================================================================== */
/* Console ( if applicable )                                                */
/* ======================================================================== */

#ifdef CONFIG_SERIAL_MPC52xx_CONSOLE

static void __init
mpc52xx_console_get_options(struct uart_port *port,
                            int *baud, int *parity, int *bits, int *flow)
{
        unsigned char mr1;

        pr_debug("mpc52xx_console_get_options(port=%p)\n", port);

        /* Read the mode registers */
        mr1 = psc_ops->get_mr1(port);

        /* CT{U,L}R are write-only ! */
        *baud = CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD;

        /* Parse them */
        switch (mr1 & MPC52xx_PSC_MODE_BITS_MASK) {
        case MPC52xx_PSC_MODE_5_BITS:
                *bits = 5;
                break;
        case MPC52xx_PSC_MODE_6_BITS:
                *bits = 6;
                break;
        case MPC52xx_PSC_MODE_7_BITS:
                *bits = 7;
                break;
        case MPC52xx_PSC_MODE_8_BITS:
        default:
                *bits = 8;
        }

        if (mr1 & MPC52xx_PSC_MODE_PARNONE)
                *parity = 'n';
        else
                *parity = mr1 & MPC52xx_PSC_MODE_PARODD ? 'o' : 'e';
}

static void
mpc52xx_console_write(struct console *co, const char *s, unsigned int count)
{
        struct uart_port *port = &mpc52xx_uart_ports[co->index];
        unsigned int i, j;

        /* Disable interrupts */
        psc_ops->cw_disable_ints(port);

        /* Wait the TX buffer to be empty */
        j = 5000000;    /* Maximum wait */
        while (!mpc52xx_uart_tx_empty(port) && --j)
                udelay(1);

        /* Write all the chars */
        for (i = 0; i < count; i++, s++) {
                /* Line return handling */
                if (*s == '\n')
                        psc_ops->write_char(port, '\r');

                /* Send the char */
                psc_ops->write_char(port, *s);

                /* Wait the TX buffer to be empty */
                j = 20000;      /* Maximum wait */
                while (!mpc52xx_uart_tx_empty(port) && --j)
                        udelay(1);
        }

        /* Restore interrupt state */
        psc_ops->cw_restore_ints(port);
}


static int __init
mpc52xx_console_setup(struct console *co, char *options)
{
        struct uart_port *port = &mpc52xx_uart_ports[co->index];
        struct device_node *np = mpc52xx_uart_nodes[co->index];
        unsigned int uartclk;
        struct resource res;
        int ret;

        int baud = CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        pr_debug("mpc52xx_console_setup co=%p, co->index=%i, options=%s\n",
                 co, co->index, options);

        if ((co->index < 0) || (co->index >= MPC52xx_PSC_MAXNUM)) {
                pr_debug("PSC%x out of range\n", co->index);
                return -EINVAL;
        }

        if (!np) {
                pr_debug("PSC%x not found in device tree\n", co->index);
                return -EINVAL;
        }

        pr_debug("Console on ttyPSC%x is %pOF\n",
                 co->index, mpc52xx_uart_nodes[co->index]);

        /* Fetch register locations */
        ret = of_address_to_resource(np, 0, &res);
        if (ret) {
                pr_debug("Could not get resources for PSC%x\n", co->index);
                return ret;
        }

        uartclk = mpc5xxx_fwnode_get_bus_frequency(of_fwnode_handle(np));
        if (uartclk == 0) {
                pr_debug("Could not find uart clock frequency!\n");
                return -EINVAL;
        }

        /* Basic port init. Needed since we use some uart_??? func before
         * real init for early access */
        spin_lock_init(&port->lock);
        port->uartclk = uartclk;
        port->ops       = &mpc52xx_uart_ops;
        port->mapbase = res.start;
        port->membase = ioremap(res.start, sizeof(struct mpc52xx_psc));
        port->irq = irq_of_parse_and_map(np, 0);

        if (port->membase == NULL)
                return -EINVAL;

        pr_debug("mpc52xx-psc uart at %p, mapped to %p, irq=%x, freq=%i\n",
                 (void *)port->mapbase, port->membase,
                 port->irq, port->uartclk);

        /* Setup the port parameters according to options */
        if (options)
                uart_parse_options(options, &baud, &parity, &bits, &flow);
        else
                mpc52xx_console_get_options(port, &baud, &parity, &bits, &flow);

        pr_debug("Setting console parameters: %i %i%c1 flow=%c\n",
                 baud, bits, parity, flow);

        return uart_set_options(port, co, baud, parity, bits, flow);
}


static struct uart_driver mpc52xx_uart_driver;

static struct console mpc52xx_console = {
        .name   = "ttyPSC",
        .write  = mpc52xx_console_write,
        .device = uart_console_device,
        .setup  = mpc52xx_console_setup,
        .flags  = CON_PRINTBUFFER,
        .index  = -1,   /* Specified on the cmdline (e.g. console=ttyPSC0) */
        .data   = &mpc52xx_uart_driver,
};


static int __init
mpc52xx_console_init(void)
{
        mpc52xx_uart_of_enumerate();
        register_console(&mpc52xx_console);
        return 0;
}

console_initcall(mpc52xx_console_init);

#define MPC52xx_PSC_CONSOLE &mpc52xx_console
#else
#define MPC52xx_PSC_CONSOLE NULL
#endif


/* ======================================================================== */
/* UART Driver                                                              */
/* ======================================================================== */

static struct uart_driver mpc52xx_uart_driver = {
        .driver_name    = "mpc52xx_psc_uart",
        .dev_name       = "ttyPSC",
        .major          = SERIAL_PSC_MAJOR,
        .minor          = SERIAL_PSC_MINOR,
        .nr             = MPC52xx_PSC_MAXNUM,
        .cons           = MPC52xx_PSC_CONSOLE,
};

/* ======================================================================== */
/* OF Platform Driver                                                       */
/* ======================================================================== */

static const struct of_device_id mpc52xx_uart_of_match[] = {
#ifdef CONFIG_PPC_MPC52xx
        { .compatible = "fsl,mpc5200b-psc-uart", .data = &mpc5200b_psc_ops, },
        { .compatible = "fsl,mpc5200-psc-uart", .data = &mpc52xx_psc_ops, },
        /* binding used by old lite5200 device trees: */
        { .compatible = "mpc5200-psc-uart", .data = &mpc52xx_psc_ops, },
        /* binding used by efika: */
        { .compatible = "mpc5200-serial", .data = &mpc52xx_psc_ops, },
#endif
#ifdef CONFIG_PPC_MPC512x
        { .compatible = "fsl,mpc5121-psc-uart", .data = &mpc512x_psc_ops, },
        { .compatible = "fsl,mpc5125-psc-uart", .data = &mpc5125_psc_ops, },
#endif
        {},
};

static int mpc52xx_uart_of_probe(struct platform_device *op)
{
        int idx = -1;
        unsigned int uartclk;
        struct uart_port *port = NULL;
        struct resource res;
        int ret;

        /* Check validity & presence */
        for (idx = 0; idx < MPC52xx_PSC_MAXNUM; idx++)
                if (mpc52xx_uart_nodes[idx] == op->dev.of_node)
                        break;
        if (idx >= MPC52xx_PSC_MAXNUM)
                return -EINVAL;
        pr_debug("Found %pOF assigned to ttyPSC%x\n",
                 mpc52xx_uart_nodes[idx], idx);

        /* set the uart clock to the input clock of the psc, the different
         * prescalers are taken into account in the set_baudrate() methods
         * of the respective chip */
        uartclk = mpc5xxx_get_bus_frequency(&op->dev);
        if (uartclk == 0) {
                dev_dbg(&op->dev, "Could not find uart clock frequency!\n");
                return -EINVAL;
        }

        /* Init the port structure */
        port = &mpc52xx_uart_ports[idx];

        spin_lock_init(&port->lock);
        port->uartclk = uartclk;
        port->fifosize  = 512;
        port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MPC52xx_CONSOLE);
        port->iotype    = UPIO_MEM;
        port->flags     = UPF_BOOT_AUTOCONF |
                          (uart_console(port) ? 0 : UPF_IOREMAP);
        port->line      = idx;
        port->ops       = &mpc52xx_uart_ops;
        port->dev       = &op->dev;

        /* Search for IRQ and mapbase */
        ret = of_address_to_resource(op->dev.of_node, 0, &res);
        if (ret)
                return ret;

        port->mapbase = res.start;
        if (!port->mapbase) {
                dev_dbg(&op->dev, "Could not allocate resources for PSC\n");
                return -EINVAL;
        }

        psc_ops->get_irq(port, op->dev.of_node);
        if (port->irq == 0) {
                dev_dbg(&op->dev, "Could not get irq\n");
                return -EINVAL;
        }

        dev_dbg(&op->dev, "mpc52xx-psc uart at %p, irq=%x, freq=%i\n",
                (void *)port->mapbase, port->irq, port->uartclk);

        /* Add the port to the uart sub-system */
        ret = uart_add_one_port(&mpc52xx_uart_driver, port);
        if (ret)
                return ret;

        platform_set_drvdata(op, (void *)port);
        return 0;
}

static void mpc52xx_uart_of_remove(struct platform_device *op)
{
        struct uart_port *port = platform_get_drvdata(op);

        if (port)
                uart_remove_one_port(&mpc52xx_uart_driver, port);
}

#ifdef CONFIG_PM
static int
mpc52xx_uart_of_suspend(struct platform_device *op, pm_message_t state)
{
        struct uart_port *port = platform_get_drvdata(op);

        if (port)
                uart_suspend_port(&mpc52xx_uart_driver, port);

        return 0;
}

static int
mpc52xx_uart_of_resume(struct platform_device *op)
{
        struct uart_port *port = platform_get_drvdata(op);

        if (port)
                uart_resume_port(&mpc52xx_uart_driver, port);

        return 0;
}
#endif

static void
mpc52xx_uart_of_assign(struct device_node *np)
{
        int i;

        /* Find the first free PSC number */
        for (i = 0; i < MPC52xx_PSC_MAXNUM; i++) {
                if (mpc52xx_uart_nodes[i] == NULL) {
                        of_node_get(np);
                        mpc52xx_uart_nodes[i] = np;
                        return;
                }
        }
}

static void
mpc52xx_uart_of_enumerate(void)
{
        static int enum_done;
        struct device_node *np;
        const struct  of_device_id *match;
        int i;

        if (enum_done)
                return;

        /* Assign index to each PSC in device tree */
        for_each_matching_node(np, mpc52xx_uart_of_match) {
                match = of_match_node(mpc52xx_uart_of_match, np);
                psc_ops = match->data;
                mpc52xx_uart_of_assign(np);
        }

        enum_done = 1;

        for (i = 0; i < MPC52xx_PSC_MAXNUM; i++) {
                if (mpc52xx_uart_nodes[i])
                        pr_debug("%pOF assigned to ttyPSC%x\n",
                                 mpc52xx_uart_nodes[i], i);
        }
}

MODULE_DEVICE_TABLE(of, mpc52xx_uart_of_match);

static struct platform_driver mpc52xx_uart_of_driver = {
        .probe          = mpc52xx_uart_of_probe,
        .remove         = mpc52xx_uart_of_remove,
#ifdef CONFIG_PM
        .suspend        = mpc52xx_uart_of_suspend,
        .resume         = mpc52xx_uart_of_resume,
#endif
        .driver = {
                .name = "mpc52xx-psc-uart",
                .of_match_table = mpc52xx_uart_of_match,
        },
};


/* ======================================================================== */
/* Module                                                                   */
/* ======================================================================== */

static int __init
mpc52xx_uart_init(void)
{
        int ret;

        printk(KERN_INFO "Serial: MPC52xx PSC UART driver\n");

        ret = uart_register_driver(&mpc52xx_uart_driver);
        if (ret) {
                printk(KERN_ERR "%s: uart_register_driver failed (%i)\n",
                       __FILE__, ret);
                return ret;
        }

        mpc52xx_uart_of_enumerate();

        /*
         * Map the PSC FIFO Controller and init if on MPC512x.
         */
        if (psc_ops && psc_ops->fifoc_init) {
                ret = psc_ops->fifoc_init();
                if (ret)
                        goto err_init;
        }

        ret = platform_driver_register(&mpc52xx_uart_of_driver);
        if (ret) {
                printk(KERN_ERR "%s: platform_driver_register failed (%i)\n",
                       __FILE__, ret);
                goto err_reg;
        }

        return 0;
err_reg:
        if (psc_ops && psc_ops->fifoc_uninit)
                psc_ops->fifoc_uninit();
err_init:
        uart_unregister_driver(&mpc52xx_uart_driver);
        return ret;
}

static void __exit
mpc52xx_uart_exit(void)
{
        if (psc_ops->fifoc_uninit)
                psc_ops->fifoc_uninit();

        platform_driver_unregister(&mpc52xx_uart_of_driver);
        uart_unregister_driver(&mpc52xx_uart_driver);
}


module_init(mpc52xx_uart_init);
module_exit(mpc52xx_uart_exit);

MODULE_AUTHOR("Sylvain Munaut <tnt@246tNt.com>");
MODULE_DESCRIPTION("Freescale MPC52xx PSC UART");
MODULE_LICENSE("GPL");