static void tegra_start_pio_tx(struct tegra_uart_port *t, unsigned int bytes)
{
if (bytes > TEGRA_UART_FIFO_SIZE)
bytes = TEGRA_UART_FIFO_SIZE;
t->fcr_shadow &= ~UART_FCR_T_TRIG_11;
t->fcr_shadow |= TEGRA_UART_TX_TRIG_8B;
uart_writeb(t, t->fcr_shadow, UART_FCR);
t->tx_in_progress = TEGRA_TX_PIO;
t->tx_bytes = bytes;
t->ier_shadow |= UART_IER_THRI;
uart_writeb(t, t->ier_shadow, UART_IER);
}
static void tegra_stop_rx(struct uart_port *u)
{
struct tegra_uart_port *t;
unsigned char ier;
t = container_of(u, struct tegra_uart_port, uport);
if (t->rts_active)
set_rts(t, false);
if (t->rx_in_progress) {
wait_sym_time(t, 1); /* wait a character interval */
ier = t->ier_shadow;
ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
UART_IER_EORD);
t->ier_shadow = ier;
uart_writeb(t, ier, UART_IER);
t->rx_in_progress = 0;
if (t->use_rx_dma && t->rx_dma)
tegra_dma_dequeue_req(t->rx_dma, &t->rx_dma_req);
else
do_handle_rx_pio(t);
tty_flip_buffer_push(u->state->port.tty);
}
return;
}
static void tegra_start_rx(struct uart_port *u)
{
struct tegra_uart_port *t;
unsigned char ier;
t = container_of(u, struct tegra_uart_port, uport);
if (t->rts_active)
set_rts(t, true);
if (!t->rx_in_progress) {
wait_sym_time(t, 1); /* wait a character interval */
/* Clear the received Bytes from FIFO */
tegra_fifo_reset(t, UART_FCR_CLEAR_RCVR);
uart_readb(t, UART_LSR);
ier = 0;
ier |= (UART_IER_RLSI | UART_IER_RTOIE);
if (t->use_rx_dma)
ier |= UART_IER_EORD;
else
ier |= UART_IER_RDI;
t->ier_shadow |= ier;
uart_writeb(t, t->ier_shadow, UART_IER);
t->rx_in_progress = 1;
if (t->use_rx_dma && t->rx_dma)
tegra_dma_enqueue_req(t->rx_dma, &t->rx_dma_req);
tty_flip_buffer_push(u->state->port.tty);
}
return;
}
static void tegra_set_baudrate(struct tegra_uart_port *t, unsigned int baud)
{
unsigned long rate;
unsigned int divisor;
unsigned char lcr;
unsigned int baud_actual;
unsigned int baud_delta;
unsigned long best_rate;
if (t->baud == baud)
return;
rate = baud * 16;
best_rate = find_best_clock_source(t, rate);
clk_set_rate(t->clk, best_rate);
rate = clk_get_rate(t->clk);
divisor = rate;
do_div(divisor, 16);
divisor += baud/2;
do_div(divisor, baud);
/* The allowable baudrate error from desired baudrate is 5% */
baud_actual = divisor ? rate / (16 * divisor) : 0;
baud_delta = abs(baud_actual - baud);
if (WARN_ON(baud_delta * 20 > baud)) {
dev_err(t->uport.dev, "requested baud %u, actual %u\n",
baud, baud_actual);
}
lcr = t->lcr_shadow;
lcr |= UART_LCR_DLAB;
uart_writeb(t, lcr, UART_LCR);
uart_writel(t, divisor & 0xFF, UART_TX);
uart_writel(t, ((divisor >> 8) & 0xFF), UART_IER);
lcr &= ~UART_LCR_DLAB;
uart_writeb(t, lcr, UART_LCR);
uart_readb(t, UART_SCR); /* Dummy read to ensure the write is posted */
t->baud = baud;
wait_sym_time(t, 2); /* wait two character intervals at new rate */
dev_dbg(t->uport.dev, "Baud %u clock freq %lu and divisor of %u\n",
baud, rate, divisor);
}
/* Flush desired FIFO. */
static void tegra_fifo_reset(struct tegra_uart_port *t, u8 fcr_bits)
{
unsigned char fcr = t->fcr_shadow;
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
uart_writeb(t, fcr, UART_FCR);
uart_readb(t, UART_SCR); /* Dummy read to ensure the write is posted */
wait_sym_time(t, 1); /* Wait for the flush to propagate. */
}
/* Flush desired FIFO. */
static void tegra_fifo_reset(struct tegra_uart_port *t, u8 fcr_bits)
{
unsigned char fcr = t->fcr_shadow;
#ifdef CONFIG_ARCH_TEGRA_2x_SOC
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
uart_writeb(t, fcr, UART_FCR);
#else
/*Hw issue: Resetting tx fifo with non-fifo
mode to avoid any extra character to be sent*/
fcr &= ~UART_FCR_ENABLE_FIFO;
uart_writeb(t, fcr, UART_FCR);
udelay(60);
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
uart_writeb(t, fcr, UART_FCR);
fcr |= UART_FCR_ENABLE_FIFO;
uart_writeb(t, fcr, UART_FCR);
#endif
uart_readb(t, UART_SCR); /* Dummy read to ensure the write is posted */
wait_sym_time(t, 1); /* Wait for the flush to propagate. */
}
static void tegra_uart_hw_deinit(struct tegra_uart_port *t)
{
unsigned long flags;
unsigned long char_time = DIV_ROUND_UP(10000000, t->baud);
unsigned long fifo_empty_time = t->uport.fifosize * char_time;
unsigned long wait_time;
unsigned char lsr;
unsigned char msr;
unsigned char mcr;
/* Disable interrupts */
uart_writeb(t, 0, UART_IER);
lsr = uart_readb(t, UART_LSR);
if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
msr = uart_readb(t, UART_MSR);
mcr = uart_readb(t, UART_MCR);
if ((mcr & UART_MCR_CTS_EN) && (msr & UART_MSR_CTS))
dev_err(t->uport.dev, "%s: Tx fifo not empty and "
"slave disabled CTS, Waiting for slave to"
" be ready\n", __func__);
/* Wait for Tx fifo to be empty */
while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
wait_time = min(fifo_empty_time, 100lu);
udelay(wait_time);
fifo_empty_time -= wait_time;
if (!fifo_empty_time) {
msr = uart_readb(t, UART_MSR);
mcr = uart_readb(t, UART_MCR);
if ((mcr & UART_MCR_CTS_EN) &&
(msr & UART_MSR_CTS))
dev_err(t->uport.dev, "%s: Slave is "
"still not ready!\n", __func__);
break;
}
lsr = uart_readb(t, UART_LSR);
}
}
spin_lock_irqsave(&t->uport.lock, flags);
/* Reset the Rx and Tx FIFOs */
tegra_fifo_reset(t, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
t->baud = 0;
t->uart_state = TEGRA_UART_CLOSED;
spin_unlock_irqrestore(&t->uport.lock, flags);
clk_disable_unprepare(t->clk);
pm_runtime_put_sync((&t->uport)->dev);
}
static void fill_tx_fifo(struct tegra_uart_port *t, int max_bytes)
{
int i;
struct circ_buf *xmit = &t->uport.state->xmit;
for (i = 0; i < max_bytes; i++) {
BUG_ON(uart_circ_empty(xmit));
uart_writeb(t, xmit->buf[xmit->tail], UART_TX);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
t->uport.icount.tx++;
}
}
static void tegra_break_ctl(struct uart_port *u, int break_ctl)
{
struct tegra_uart_port *t;
unsigned char lcr;
t = container_of(u, struct tegra_uart_port, uport);
lcr = t->lcr_shadow;
if (break_ctl)
lcr |= UART_LCR_SBC;
else
lcr &= ~UART_LCR_SBC;
uart_writeb(t, lcr, UART_LCR);
t->lcr_shadow = lcr;
}
static void set_dtr(struct tegra_uart_port *t, bool active)
{
unsigned char mcr;
mcr = t->mcr_shadow;
if (active)
mcr |= UART_MCR_DTR;
else
mcr &= ~UART_MCR_DTR;
if (mcr != t->mcr_shadow) {
uart_writeb(t, mcr, UART_MCR);
t->mcr_shadow = mcr;
}
return;
}
static void tegra_start_dma_tx(struct tegra_uart_port *t, unsigned long bytes)
{
struct circ_buf *xmit;
xmit = &t->uport.state->xmit;
dma_sync_single_for_device(t->uport.dev, t->xmit_dma_addr,
UART_XMIT_SIZE, DMA_TO_DEVICE);
t->fcr_shadow &= ~UART_FCR_T_TRIG_11;
t->fcr_shadow |= TEGRA_UART_TX_TRIG_4B;
uart_writeb(t, t->fcr_shadow, UART_FCR);
t->tx_bytes = bytes & ~(sizeof(u32)-1);
t->tx_dma_req.source_addr = t->xmit_dma_addr + xmit->tail;
t->tx_dma_req.size = t->tx_bytes;
t->tx_in_progress = TEGRA_TX_DMA;
tegra_dma_enqueue_req(t->tx_dma, &t->tx_dma_req);
}
static void fill_tx_fifo(struct tegra_uart_port *t, int max_bytes)
{
int i;
struct circ_buf *xmit = &t->uport.state->xmit;
#ifndef CONFIG_ARCH_TEGRA_2x_SOC
unsigned long lsr;
#endif
for (i = 0; i < max_bytes; i++) {
BUG_ON(uart_circ_empty(xmit));
#ifndef CONFIG_ARCH_TEGRA_2x_SOC
lsr = uart_readl(t, UART_LSR);
if ((lsr & UART_LSR_TXFIFO_FULL))
break;
#endif
uart_writeb(t, xmit->buf[xmit->tail], UART_TX);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
t->uport.icount.tx++;
}
}
static void tegra_uart_hw_deinit(struct tegra_uart_port *t)
{
unsigned long flags;
/* Disable interrupts */
uart_writeb(t, 0, UART_IER);
while ((uart_readb(t, UART_LSR) & UART_LSR_TEMT) != UART_LSR_TEMT);
udelay(200);
spin_lock_irqsave(&t->uport.lock, flags);
/* Reset the Rx and Tx FIFOs */
tegra_fifo_reset(t, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
clk_disable(t->clk);
t->baud = 0;
t->uart_state = TEGRA_UART_CLOSED;
spin_unlock_irqrestore(&t->uport.lock, flags);
}
static int tegra_uart_hw_init(struct tegra_uart_port *t)
{
unsigned char ier;
unsigned char sir;
dev_vdbg(t->uport.dev, "+tegra_uart_hw_init\n");
t->fcr_shadow = 0;
t->mcr_shadow = 0;
t->lcr_shadow = 0;
t->ier_shadow = 0;
t->baud = 0;
pm_runtime_get_sync((&t->uport)->dev);
clk_prepare_enable(t->clk);
/* Reset the UART controller to clear all previous status.*/
tegra_periph_reset_assert(t->clk);
udelay(100);
tegra_periph_reset_deassert(t->clk);
udelay(100);
t->rx_in_progress = 0;
/*
* Set the trigger level
*
* For PIO mode:
*
* For receive, this will interrupt the CPU after that many number of
* bytes are received, for the remaining bytes the receive timeout
* interrupt is received.
*
* Rx high watermark is set to 4.
*
* For transmit, if the trasnmit interrupt is enabled, this will
* interrupt the CPU when the number of entries in the FIFO reaches the
* low watermark.
*
* Tx low watermark is set to 8.
*
* For DMA mode:
*
* Set the Tx trigger to 4. This should match the DMA burst size that
* programmed in the DMA registers.
*/
t->fcr_shadow = UART_FCR_ENABLE_FIFO;
t->fcr_shadow |= UART_FCR_R_TRIG_01;
t->fcr_shadow |= TEGRA_UART_TX_TRIG_8B;
uart_writeb(t, t->fcr_shadow, UART_FCR);
if (t->use_rx_dma) {
/*
* Initialize the UART for a simple default configuration
* so that the receive DMA buffer may be enqueued */
t->lcr_shadow = 3; /* no parity, stop, 8 data bits */
tegra_set_baudrate(t, 115200);
t->fcr_shadow |= UART_FCR_DMA_SELECT;
uart_writeb(t, t->fcr_shadow, UART_FCR);
if (tegra_start_dma_rx(t)) {
dev_err(t->uport.dev, "Rx DMA enqueue failed\n");
tegra_uart_free_rx_dma(t);
t->fcr_shadow &= ~UART_FCR_DMA_SELECT;
uart_writeb(t, t->fcr_shadow, UART_FCR);
}
} else {
uart_writeb(t, t->fcr_shadow, UART_FCR);
}
t->rx_in_progress = 1;
/*
* Enable IE_RXS for the receive status interrupts like line errros.
* Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd.
*
* If using DMA mode, enable EORD instead of receive interrupt which
* will interrupt after the UART is done with the receive instead of
* the interrupt when the FIFO "threshold" is reached.
*
* EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when
* the DATA is sitting in the FIFO and couldn't be transferred to the
* DMA as the DMA size alignment(4 bytes) is not met. EORD will be
* triggered when there is a pause of the incomming data stream for 4
* characters long.
*
* For pauses in the data which is not aligned to 4 bytes, we get
* both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first
* then the EORD.
*
* Don't get confused, believe in the magic of nvidia hw...:-)
*/
ier = 0;
ier |= UART_IER_RLSI | UART_IER_RTOIE;
if (t->use_rx_dma)
ier |= UART_IER_EORD;
else
ier |= UART_IER_RDI;
t->ier_shadow = ier;
uart_writeb(t, ier, UART_IER);
/*
* Tegra UART controller also support SIR PHY
* Enabled IRDA will transmit each zero bit as a short IR pulse.
*/
if (t->is_irda) {
dev_vdbg(t->uport.dev, "SIR enabled\n");
sir = TEGRA_UART_SIR_ENABLED;
uart_writeb(t, sir, TEGRA_UART_IRDA_CSR);
}
t->uart_state = TEGRA_UART_OPENED;
dev_vdbg(t->uport.dev, "-tegra_uart_hw_init\n");
return 0;
}
static irqreturn_t tegra_uart_isr(int irq, void *data)
{
struct tegra_uart_port *t = data;
struct uart_port *u = &t->uport;
unsigned char iir;
unsigned char ier;
bool is_rx_int = false;
unsigned long flags;
spin_lock_irqsave(&u->lock, flags);
t = container_of(u, struct tegra_uart_port, uport);
while (1) {
iir = uart_readb(t, UART_IIR);
if (iir & UART_IIR_NO_INT) {
if (likely(t->use_rx_dma) && is_rx_int) {
do_handle_rx_dma(t);
if (t->rx_in_progress) {
ier = t->ier_shadow;
ier |= (UART_IER_RLSI | UART_IER_RTOIE |
UART_IER_EORD);
t->ier_shadow = ier;
uart_writeb(t, ier, UART_IER);
}
}
spin_unlock_irqrestore(&u->lock, flags);
return IRQ_HANDLED;
}
dev_dbg(u->dev, "tegra_uart_isr iir = 0x%x (%d)\n", iir,
(iir >> 1) & 0x7);
switch ((iir >> 1) & 0x7) {
case 0: /* Modem signal change interrupt */
do_handle_modem_signal(u);
break;
case 1: /* Transmit interrupt only triggered when using PIO */
t->ier_shadow &= ~UART_IER_THRI;
uart_writeb(t, t->ier_shadow, UART_IER);
do_handle_tx_pio(t);
break;
case 4: /* End of data */
case 6: /* Rx timeout */
case 2: /* Receive */
if (likely(t->use_rx_dma)) {
if (!is_rx_int) {
is_rx_int = true;
/* Disable interrups */
ier = t->ier_shadow;
ier |= UART_IER_RDI;
uart_writeb(t, ier, UART_IER);
ier &= ~(UART_IER_RDI | UART_IER_RLSI |
UART_IER_RTOIE | UART_IER_EORD);
t->ier_shadow = ier;
uart_writeb(t, ier, UART_IER);
}
} else {
do_handle_rx_pio(t);
spin_unlock_irqrestore(&u->lock, flags);
tty_flip_buffer_push(u->state->port.tty);
spin_lock_irqsave(&u->lock, flags);
}
break;
case 3: /* Receive error */
/* FIXME how to handle this? Why do we get here */
do_decode_rx_error(t, uart_readb(t, UART_LSR));
break;
case 5: /* break nothing to handle */
case 7: /* break nothing to handle */
break;
}
}
}
static void tegra_set_termios(struct uart_port *u, struct ktermios *termios,
struct ktermios *oldtermios)
{
struct tegra_uart_port *t;
unsigned int baud;
unsigned long flags;
unsigned int lcr;
unsigned int c_cflag = termios->c_cflag;
unsigned char mcr;
t = container_of(u, struct tegra_uart_port, uport);
dev_vdbg(t->uport.dev, "+tegra_set_termios\n");
spin_lock_irqsave(&u->lock, flags);
/* Changing configuration, it is safe to stop any rx now */
if (t->rts_active)
set_rts(t, false);
/* Clear all interrupts as configuration is going to be change */
uart_writeb(t, t->ier_shadow | UART_IER_RDI, UART_IER);
uart_readb(t, UART_IER);
uart_writeb(t, 0, UART_IER);
uart_readb(t, UART_IER);
/* Parity */
lcr = t->lcr_shadow;
lcr &= ~UART_LCR_PARITY;
if (PARENB == (c_cflag & PARENB)) {
if (CMSPAR == (c_cflag & CMSPAR)) {
/* FIXME What is space parity? */
/* data |= SPACE_PARITY; */
} else if (c_cflag & PARODD) {
lcr |= UART_LCR_PARITY;
lcr &= ~UART_LCR_EPAR;
lcr &= ~UART_LCR_SPAR;
} else {
lcr |= UART_LCR_PARITY;
lcr |= UART_LCR_EPAR;
lcr &= ~UART_LCR_SPAR;
}
}
lcr &= ~UART_LCR_WLEN8;
switch (c_cflag & CSIZE) {
case CS5:
lcr |= UART_LCR_WLEN5;
break;
case CS6:
lcr |= UART_LCR_WLEN6;
break;
case CS7:
lcr |= UART_LCR_WLEN7;
break;
default:
lcr |= UART_LCR_WLEN8;
break;
}
/* Stop bits */
if (termios->c_cflag & CSTOPB)
lcr |= UART_LCR_STOP;
else
lcr &= ~UART_LCR_STOP;
uart_writeb(t, lcr, UART_LCR);
t->lcr_shadow = lcr;
/* Baud rate. */
baud = uart_get_baud_rate(u, termios, oldtermios, 200, 4000000);
spin_unlock_irqrestore(&u->lock, flags);
tegra_set_baudrate(t, baud);
spin_lock_irqsave(&u->lock, flags);
/* Flow control */
if (termios->c_cflag & CRTSCTS) {
mcr = t->mcr_shadow;
mcr |= UART_MCR_CTS_EN;
mcr &= ~UART_MCR_RTS_EN;
t->mcr_shadow = mcr;
uart_writeb(t, mcr, UART_MCR);
t->use_cts_control = true;
/* if top layer has asked to set rts active then do so here */
if (t->rts_active)
set_rts(t, true);
} else {
mcr = t->mcr_shadow;
mcr &= ~UART_MCR_CTS_EN;
mcr &= ~UART_MCR_RTS_EN;
t->mcr_shadow = mcr;
uart_writeb(t, mcr, UART_MCR);
t->use_cts_control = false;
}
/* update the port timeout based on new settings */
uart_update_timeout(u, termios->c_cflag, baud);
/* Make sure all write has completed */
uart_readb(t, UART_IER);
/* Reenable interrupt */
uart_writeb(t, t->ier_shadow, UART_IER);
uart_readb(t, UART_IER);
spin_unlock_irqrestore(&u->lock, flags);
dev_vdbg(t->uport.dev, "-tegra_set_termios\n");
return;
}