eth_at91.c

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#include "cfg/cfg_eth.h"

#define LOG_LEVEL  ETH_LOG_LEVEL
#define LOG_FORMAT ETH_LOG_FORMAT

#include <cfg/log.h>

#include <cfg/debug.h>
#include <cfg/log.h>
#include <cfg/macros.h>
#include <cfg/compiler.h>

#include <io/at91sam7.h>
#include <io/arm.h>

#include <cpu/power.h>
#include <cpu/types.h>
#include <cpu/irq.h>

#include <drv/timer.h>
#include <drv/eth.h>

#include <mware/event.h>

#include <string.h>

#include "eth_at91.h"

#define EMAC_RX_INTS    (BV(EMAC_RCOMP) | BV(EMAC_ROVR) | BV(EMAC_RXUBR))
#define EMAC_TX_INTS    (BV(EMAC_TCOMP) | BV(EMAC_TXUBR) | BV(EMAC_RLEX))

/* Silent Doxygen bug... */
#ifndef __doxygen__
/*
 * NOTE: this buffer should be declared as 'volatile' because it is read by the
 * hardware. However, this is accessed only via memcpy() that should guarantee
 * coherency when copying from/to buffers.
 */
static uint8_t tx_buf[EMAC_TX_BUFFERS * EMAC_TX_BUFSIZ] ALIGNED(8);
static volatile BufDescriptor tx_buf_tab[EMAC_TX_DESCRIPTORS] ALIGNED(8);

/*
 * NOTE: this buffer should be declared as 'volatile' because it is wrote by
 * the hardware. However, this is accessed only via memcpy() that should
 * guarantee coherency when copying from/to buffers.
 */
static uint8_t rx_buf[EMAC_RX_BUFFERS * EMAC_RX_BUFSIZ] ALIGNED(8);
static volatile BufDescriptor rx_buf_tab[EMAC_RX_DESCRIPTORS] ALIGNED(8);
#endif

static int tx_buf_idx;
static int tx_buf_offset;
static int rx_buf_idx;

static Event recv_wait, send_wait;

static DECLARE_ISR(emac_irqHandler)
{
    /* Read interrupt status and disable interrupts. */
    uint32_t isr = EMAC_ISR;

    /* Receiver interrupt */
    if ((isr & EMAC_RX_INTS))
    {
        if (isr & BV(EMAC_RCOMP))
            event_do(&recv_wait);
        EMAC_RSR = EMAC_RX_INTS;
    }
    /* Transmitter interrupt */
    if (isr & EMAC_TX_INTS)
    {
        if (isr & BV(EMAC_TCOMP))
            event_do(&send_wait);
        EMAC_TSR = EMAC_TX_INTS;
    }
    AIC_EOICR = 0;
}

/*
 * \brief Read contents of PHY register.
 *
 * \param reg PHY register number.
 *
 * \return Contents of the specified register.
 */
static uint16_t phy_hw_read(reg8_t reg)
{
    // PHY read command.
    EMAC_MAN = EMAC_SOF | EMAC_RW_READ | (NIC_PHY_ADDR << EMAC_PHYA_SHIFT)
            | ((reg  << EMAC_REGA_SHIFT) & EMAC_REGA) | EMAC_CODE;

    // Wait until PHY logic completed.
    while (!(EMAC_NSR & BV(EMAC_IDLE)))
        cpu_relax();

    // Get data from PHY maintenance register.
    return (uint16_t)(EMAC_MAN & EMAC_DATA);
}

/*
 * \brief Write value to PHY register.
 *
 * \param reg PHY register number.
 * \param val Value to write.
 */
static void phy_hw_write(reg8_t reg, uint16_t val)
{
    // PHY write command.
    EMAC_MAN = EMAC_SOF | EMAC_RW_WRITE | (NIC_PHY_ADDR << EMAC_PHYA_SHIFT)
            | ((reg  << EMAC_REGA_SHIFT) & EMAC_REGA) | EMAC_CODE | val;

    // Wait until PHY logic completed.
    while (!(EMAC_NSR & BV(EMAC_IDLE)))
        cpu_relax();
}

static int emac_reset(void)
{
    uint16_t phy_cr;

    // Enable devices
    PMC_PCER = BV(PIOA_ID);
    PMC_PCER = BV(PIOB_ID);
    PMC_PCER = BV(EMAC_ID);

    // Disable RMII and TESTMODE by disabling pull-ups.
    PIOB_PUDR = BV(PHY_COL_RMII_BIT) | BV(PHY_RXDV_TESTMODE_BIT);

    // Disable PHY power down.
    PIOB_PER  = BV(PHY_PWRDN_BIT);
    PIOB_OER  = BV(PHY_PWRDN_BIT);
    PIOB_CODR = BV(PHY_PWRDN_BIT);

    // Toggle external hardware reset pin.
    RSTC_MR = RSTC_KEY | (1 << RSTC_ERSTL_SHIFT) | BV(RSTC_URSTEN);
    RSTC_CR = RSTC_KEY | BV(RSTC_EXTRST);

    while ((RSTC_SR & BV(RSTC_NRSTL)) == 0)
        cpu_relax();

    // Configure MII port.
    PIOB_ASR = PHY_MII_PINS;
    PIOB_BSR = 0;
    PIOB_PDR = PHY_MII_PINS;

    // Enable receive and transmit clocks.
    EMAC_USRIO = BV(EMAC_CLKEN);

    // Enable management port.
    EMAC_NCR |= BV(EMAC_MPE);
    EMAC_NCFGR |= EMAC_CLK_HCLK_32;

    // Set local MAC address.
    EMAC_SA1L = (mac_addr[3] << 24) | (mac_addr[2] << 16) |
                (mac_addr[1] << 8) | mac_addr[0];
    EMAC_SA1H = (mac_addr[5] << 8) | mac_addr[4];

    // Wait for PHY ready
    timer_delay(255);

    // Clear MII isolate.
    phy_hw_read(NIC_PHY_BMCR);
    phy_cr = phy_hw_read(NIC_PHY_BMCR);

    phy_cr &= ~NIC_PHY_BMCR_ISOLATE;
    phy_hw_write(NIC_PHY_BMCR, phy_cr);

    phy_cr = phy_hw_read(NIC_PHY_BMCR);

    LOG_INFO("%s: PHY ID %#04x %#04x\n",
        __func__,
        phy_hw_read(NIC_PHY_ID1), phy_hw_read(NIC_PHY_ID2));

    // Wait for auto negotiation completed.
    phy_hw_read(NIC_PHY_BMSR);
    for (;;)
    {
        if (phy_hw_read(NIC_PHY_BMSR) & NIC_PHY_BMSR_ANCOMPL)
            break;
        cpu_relax();
    }

    // Disable management port.
    EMAC_NCR &= ~BV(EMAC_MPE);

    return 0;
}

static int emac_start(void)
{
    uint32_t addr;
    int i;

    for (i = 0; i < EMAC_RX_DESCRIPTORS; i++)
    {
        addr = (uint32_t)(rx_buf + (i * EMAC_RX_BUFSIZ));
        rx_buf_tab[i].addr = addr & BUF_ADDRMASK;
    }
    rx_buf_tab[EMAC_RX_DESCRIPTORS - 1].addr |= RXBUF_WRAP;

    for (i = 0; i < EMAC_TX_DESCRIPTORS; i++)
    {
        addr = (uint32_t)(tx_buf + (i * EMAC_TX_BUFSIZ));
        tx_buf_tab[i].addr = addr & BUF_ADDRMASK;
        tx_buf_tab[i].stat = TXS_USED;
    }
    tx_buf_tab[EMAC_TX_DESCRIPTORS - 1].stat = TXS_USED | TXS_WRAP;

    /* Tell the EMAC where to find the descriptors. */
    EMAC_RBQP = (uint32_t)rx_buf_tab;
    EMAC_TBQP = (uint32_t)tx_buf_tab;

    /* Clear receiver status. */
    EMAC_RSR = BV(EMAC_OVR) | BV(EMAC_REC) | BV(EMAC_BNA);

    /* Copy all frames and discard FCS. */
    EMAC_NCFGR |= BV(EMAC_CAF) | BV(EMAC_DRFCS);

    /* Enable receiver, transmitter and statistics. */
    EMAC_NCR |= BV(EMAC_TE) | BV(EMAC_RE) | BV(EMAC_WESTAT);

    return 0;
}

ssize_t eth_putFrame(const uint8_t *buf, size_t len)
{
    size_t wr_len;

    if (UNLIKELY(!len))
        return -1;
    ASSERT(len <= sizeof(tx_buf));

        /* Check if the transmit buffer is available */
    while (!(tx_buf_tab[tx_buf_idx].stat & TXS_USED))
        event_wait(&send_wait);

        /* Copy the data into the buffer and prepare descriptor */
        wr_len = MIN(len, (size_t)EMAC_TX_BUFSIZ - tx_buf_offset);
        memcpy((uint8_t *)tx_buf_tab[tx_buf_idx].addr + tx_buf_offset,
                buf, wr_len);
    tx_buf_offset += wr_len;

    return wr_len;
}

void eth_sendFrame(void)
{
        tx_buf_tab[tx_buf_idx].stat = (tx_buf_offset & TXS_LENGTH_FRAME) |
            TXS_LAST_BUFF |
            ((tx_buf_idx == EMAC_TX_DESCRIPTORS - 1) ?  TXS_WRAP : 0);
    EMAC_NCR |= BV(EMAC_TSTART);

    tx_buf_offset = 0;
    if (++tx_buf_idx >= EMAC_TX_DESCRIPTORS)
        tx_buf_idx = 0;
}

ssize_t eth_send(const uint8_t *buf, size_t len)
 {
    if (UNLIKELY(!len))
        return -1;

    len = eth_putFrame(buf, len);
    eth_sendFrame();

    return len;
}

static void eth_buf_realign(int idx)
{
    /* Empty buffer found. Realign. */
    do {
        rx_buf_tab[rx_buf_idx].addr &= ~RXBUF_OWNERSHIP;
        if (++rx_buf_idx >= EMAC_RX_BUFFERS)
            rx_buf_idx = 0;
    } while (idx != rx_buf_idx);
}

static size_t __eth_getFrameLen(void)
{
    int idx, n = EMAC_RX_BUFFERS;

skip:
    /* Skip empty buffers */
    while ((n > 0) && !(rx_buf_tab[rx_buf_idx].addr & RXBUF_OWNERSHIP))
    {
        if (++rx_buf_idx >= EMAC_RX_BUFFERS)
            rx_buf_idx = 0;
        n--;
    }
    if (UNLIKELY(!n))
    {
        LOG_INFO("no frame found\n");
        return 0;
    }
    /* Search the start of frame and cleanup fragments */
    while ((n > 0) && (rx_buf_tab[rx_buf_idx].addr & RXBUF_OWNERSHIP) &&
            !(rx_buf_tab[rx_buf_idx].stat & RXS_SOF))
    {
        rx_buf_tab[rx_buf_idx].addr &= ~RXBUF_OWNERSHIP;
        if (++rx_buf_idx >= EMAC_RX_BUFFERS)
            rx_buf_idx = 0;
        n--;
    }
    if (UNLIKELY(!n))
    {
        LOG_INFO("no SOF found\n");
        return 0;
    }
    /* Search end of frame to evaluate the total frame size */
    idx = rx_buf_idx;
restart:
    while (n > 0)
    {
        if (UNLIKELY(!(rx_buf_tab[idx].addr & RXBUF_OWNERSHIP)))
        {
            /* Empty buffer found. Realign. */
            eth_buf_realign(idx);
            goto skip;
        }
        if (rx_buf_tab[idx].stat & RXS_EOF)
            return rx_buf_tab[idx].stat & RXS_LENGTH_FRAME;
        if (UNLIKELY((idx != rx_buf_idx) &&
                (rx_buf_tab[idx].stat & RXS_SOF)))
        {
            /* Another start of frame found. Realign. */
            eth_buf_realign(idx);
            goto restart;
        }
        if (++idx >= EMAC_RX_BUFFERS)
            idx = 0;
        n--;
    }
    LOG_INFO("no EOF found\n");
    return 0;
}

size_t eth_getFrameLen(void)
{
    size_t len;

    /* Check if there is at least one available frame in the buffer */
    while (1)
    {
        len = __eth_getFrameLen();
        if (LIKELY(len))
            break;
        /* Wait for RX interrupt */
        event_wait(&recv_wait);
    }
    return len;
}

ssize_t eth_getFrame(uint8_t *buf, size_t len)
{
    uint8_t *addr;
    size_t rd_len = 0;

    if (UNLIKELY(!len))
        return -1;
    ASSERT(len <= sizeof(rx_buf));

    /* Copy data from the RX buffer */
    addr = (uint8_t *)(rx_buf_tab[rx_buf_idx].addr & BUF_ADDRMASK);
    if (addr + len > &rx_buf[countof(rx_buf)])
    {
        size_t count = &rx_buf[countof(rx_buf)] - addr;

        memcpy(buf, addr, count);
        memcpy(buf + count, rx_buf, len - count);
    }
    else
    {
        memcpy(buf, addr, len);
    }
    /* Update descriptors */
    while (rd_len < len)
    {
        if (len - rd_len >= EMAC_RX_BUFSIZ)
            rd_len += EMAC_RX_BUFSIZ;
        else
            rd_len += len - rd_len;
        if (UNLIKELY(!(rx_buf_tab[rx_buf_idx].addr & RXBUF_OWNERSHIP)))
        {
            LOG_INFO("bad frame found\n");
            return 0;
        }
        rx_buf_tab[rx_buf_idx].addr &= ~RXBUF_OWNERSHIP;
        if (++rx_buf_idx >= EMAC_RX_DESCRIPTORS)
            rx_buf_idx = 0;
    }

    return rd_len;
}

ssize_t eth_recv(uint8_t *buf, size_t len)
{
    if (UNLIKELY(!len))
        return -1;
    len = MIN(len, eth_getFrameLen());
    return len ? eth_getFrame(buf, len) : 0;
}

int eth_init()
{
    cpu_flags_t flags;

    emac_reset();
    emac_start();

    event_initGeneric(&recv_wait);
    event_initGeneric(&send_wait);

    // Register interrupt vector
    IRQ_SAVE_DISABLE(flags);

    /* Disable all emac interrupts */
    EMAC_IDR = 0xFFFFFFFF;

    /* Set the vector. */
    AIC_SVR(EMAC_ID) = emac_irqHandler;
    /* Initialize to edge triggered with defined priority. */
    AIC_SMR(EMAC_ID) = AIC_SRCTYPE_INT_EDGE_TRIGGERED;
    /* Clear pending interrupt */
    AIC_ICCR = BV(EMAC_ID);
    /* Enable the system IRQ */
    AIC_IECR = BV(EMAC_ID);

    /* Enable interrupts */
    EMAC_IER = EMAC_RX_INTS | EMAC_TX_INTS;

    IRQ_RESTORE(flags);

    return 0;
}