cpm-serial.c

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/*
 * CPM serial console support.
 *
 * Copyright 2007 Freescale Semiconductor, Inc.
 * Author: Scott Wood <[email protected]>
 *
 * It is assumed that the firmware (or the platform file) has already set
 * up the port.
 */

#include "types.h"
#include "io.h"
#include "ops.h"
#include "page.h"

struct cpm_scc {
    u32 gsmrl;
    u32 gsmrh;
    u16 psmr;
    u8 res1[2];
    u16 todr;
    u16 dsr;
    u16 scce;
    u8 res2[2];
    u16 sccm;
    u8 res3;
    u8 sccs;
    u8 res4[8];
};

struct cpm_smc {
    u8 res1[2];
    u16 smcmr;
    u8 res2[2];
    u8 smce;
    u8 res3[3];
    u8 smcm;
    u8 res4[5];
};

struct cpm_param {
    u16 rbase;
    u16 tbase;
    u8 rfcr;
    u8 tfcr;
    u16 mrblr;
    u32 rstate;
    u8 res1[4];
    u16 rbptr;
    u8 res2[6];
    u32 tstate;
    u8 res3[4];
    u16 tbptr;
    u8 res4[6];
    u16 maxidl;
    u16 idlc;
    u16 brkln;
    u16 brkec;
    u16 brkcr;
    u16 rmask;
    u8 res5[4];
};

struct cpm_bd {
    u16 sc;   /* Status and Control */
    u16 len;  /* Data length in buffer */
    u8 *addr; /* Buffer address in host memory */
};

static void *cpcr;
static struct cpm_param *param;
static struct cpm_smc *smc;
static struct cpm_scc *scc;
static struct cpm_bd *tbdf, *rbdf;
static u32 cpm_cmd;
static void *cbd_addr;
static u32 cbd_offset;

static void (*do_cmd)(int op);
static void (*enable_port)(void);
static void (*disable_port)(void);

#define CPM_CMD_STOP_TX     4
#define CPM_CMD_RESTART_TX  6
#define CPM_CMD_INIT_RX_TX  0

static void cpm1_cmd(int op)
{
    while (in_be16(cpcr) & 1)
        ;

    out_be16(cpcr, (op << 8) | cpm_cmd | 1);

    while (in_be16(cpcr) & 1)
        ;
}

static void cpm2_cmd(int op)
{
    while (in_be32(cpcr) & 0x10000)
        ;

    out_be32(cpcr, op | cpm_cmd | 0x10000);

    while (in_be32(cpcr) & 0x10000)
        ;
}

static void smc_disable_port(void)
{
    do_cmd(CPM_CMD_STOP_TX);
    out_be16(&smc->smcmr, in_be16(&smc->smcmr) & ~3);
}

static void scc_disable_port(void)
{
    do_cmd(CPM_CMD_STOP_TX);
    out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) & ~0x30);
}

static void smc_enable_port(void)
{
    out_be16(&smc->smcmr, in_be16(&smc->smcmr) | 3);
    do_cmd(CPM_CMD_RESTART_TX);
}

static void scc_enable_port(void)
{
    out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) | 0x30);
    do_cmd(CPM_CMD_RESTART_TX);
}

static int cpm_serial_open(void)
{
    disable_port();

    out_8(&param->rfcr, 0x10);
    out_8(&param->tfcr, 0x10);
    out_be16(&param->mrblr, 1);
    out_be16(&param->maxidl, 0);
    out_be16(&param->brkec, 0);
    out_be16(&param->brkln, 0);
    out_be16(&param->brkcr, 0);

    rbdf = cbd_addr;
    rbdf->addr = (u8 *)rbdf - 1;
    rbdf->sc = 0xa000;
    rbdf->len = 1;

    tbdf = rbdf + 1;
    tbdf->addr = (u8 *)rbdf - 2;
    tbdf->sc = 0x2000;
    tbdf->len = 1;

    sync();
    out_be16(&param->rbase, cbd_offset);
    out_be16(&param->tbase, cbd_offset + sizeof(struct cpm_bd));

    do_cmd(CPM_CMD_INIT_RX_TX);

    enable_port();
    return 0;
}

static void cpm_serial_putc(unsigned char c)
{
    while (tbdf->sc & 0x8000)
        barrier();

    sync();

    tbdf->addr[0] = c;
    eieio();
    tbdf->sc |= 0x8000;
}

static unsigned char cpm_serial_tstc(void)
{
    barrier();
    return !(rbdf->sc & 0x8000);
}

static unsigned char cpm_serial_getc(void)
{
    unsigned char c;

    while (!cpm_serial_tstc())
        ;

    sync();
    c = rbdf->addr[0];
    eieio();
    rbdf->sc |= 0x8000;

    return c;
}

int cpm_console_init(void *devp, struct serial_console_data *scdp)
{
    void *vreg[2];
    u32 reg[2];
    int is_smc = 0, is_cpm2 = 0;
    void *parent, *muram;
    void *muram_addr;
    unsigned long muram_offset, muram_size;

    if (dt_is_compatible(devp, "fsl,cpm1-smc-uart")) {
        is_smc = 1;
    } else if (dt_is_compatible(devp, "fsl,cpm2-scc-uart")) {
        is_cpm2 = 1;
    } else if (dt_is_compatible(devp, "fsl,cpm2-smc-uart")) {
        is_cpm2 = 1;
        is_smc = 1;
    }

    if (is_smc) {
        enable_port = smc_enable_port;
        disable_port = smc_disable_port;
    } else {
        enable_port = scc_enable_port;
        disable_port = scc_disable_port;
    }

    if (is_cpm2)
        do_cmd = cpm2_cmd;
    else
        do_cmd = cpm1_cmd;

    if (getprop(devp, "fsl,cpm-command", &cpm_cmd, 4) < 4)
        return -1;

    if (dt_get_virtual_reg(devp, vreg, 2) < 2)
        return -1;

    if (is_smc)
        smc = vreg[0];
    else
        scc = vreg[0];

    param = vreg[1];

    parent = get_parent(devp);
    if (!parent)
        return -1;

    if (dt_get_virtual_reg(parent, &cpcr, 1) < 1)
        return -1;

    muram = finddevice("/soc/cpm/muram/data");
    if (!muram)
        return -1;

    /* For bootwrapper-compatible device trees, we assume that the first
     * entry has at least 128 bytes, and that #address-cells/#data-cells
     * is one for both parent and child.
     */

    if (dt_get_virtual_reg(muram, &muram_addr, 1) < 1)
        return -1;

    if (getprop(muram, "reg", reg, 8) < 8)
        return -1;

    muram_offset = reg[0];
    muram_size = reg[1];

    /* Store the buffer descriptors at the end of the first muram chunk.
     * For SMC ports on CPM2-based platforms, relocate the parameter RAM
     * just before the buffer descriptors.
     */

    cbd_offset = muram_offset + muram_size - 2 * sizeof(struct cpm_bd);

    if (is_cpm2 && is_smc) {
        u16 *smc_base = (u16 *)param;
        u16 pram_offset;

        pram_offset = cbd_offset - 64;
        pram_offset = _ALIGN_DOWN(pram_offset, 64);

        disable_port();
        out_be16(smc_base, pram_offset);
        param = muram_addr - muram_offset + pram_offset;
    }

    cbd_addr = muram_addr - muram_offset + cbd_offset;

    scdp->open = cpm_serial_open;
    scdp->putc = cpm_serial_putc;
    scdp->getc = cpm_serial_getc;
    scdp->tstc = cpm_serial_tstc;

    return 0;
}