static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
{
unsigned long fcr = tup->fcr_shadow;
int ret;
if (tup->cdata->allow_txfifo_reset_fifo_mode) {
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
tegra_uart_write(tup, fcr, UART_FCR);
} else {
fcr &= ~UART_FCR_ENABLE_FIFO;
tegra_uart_write(tup, fcr, UART_FCR);
udelay(60);
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
tegra_uart_write(tup, fcr, UART_FCR);
fcr |= UART_FCR_ENABLE_FIFO;
tegra_uart_write(tup, fcr, UART_FCR);
if (tup->cdata->fifo_mode_enable_status) {
ret = tegra_uart_is_fifo_mode_enabled(tup);
if (ret < 0)
dev_err(tup->uport.dev, "FIFO mode not enabled\n");
}
}
/* Dummy read to ensure the write is posted */
tegra_uart_read(tup, UART_SCR);
/* Wait for the flush to propagate. */
tegra_uart_wait_sym_time(tup, 2);
}
static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
{
unsigned long fcr = tup->fcr_shadow;
if (tup->cdata->allow_txfifo_reset_fifo_mode) {
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
tegra_uart_write(tup, fcr, UART_FCR);
} else {
fcr &= ~UART_FCR_ENABLE_FIFO;
tegra_uart_write(tup, fcr, UART_FCR);
udelay(60);
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
tegra_uart_write(tup, fcr, UART_FCR);
fcr |= UART_FCR_ENABLE_FIFO;
tegra_uart_write(tup, fcr, UART_FCR);
}
/* Dummy read to ensure the write is posted */
tegra_uart_read(tup, UART_SCR);
/*
* For all tegra devices (up to t210), there is a hardware issue that
* requires software to wait for 32 UART clock periods for the flush
* to propagate, otherwise data could be lost.
*/
tegra_uart_wait_cycle_time(tup, 32);
}
static void tegra_uart_enable_ms(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
if (tup->enable_modem_interrupt) {
tup->ier_shadow |= UART_IER_MSI;
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
}
}
static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
{
unsigned long rate;
unsigned int divisor;
unsigned long lcr;
int ret;
if (tup->current_baud == baud)
return 0;
if (tup->cdata->support_clk_src_div) {
rate = baud * 16;
ret = clk_set_rate(tup->uart_clk, rate);
if (ret < 0) {
dev_err(tup->uport.dev,
"clk_set_rate() failed for rate %lu\n", rate);
return ret;
}
divisor = 1;
} else {
rate = clk_get_rate(tup->uart_clk);
divisor = DIV_ROUND_CLOSEST(rate, baud * 16);
}
lcr = tup->lcr_shadow;
lcr |= UART_LCR_DLAB;
tegra_uart_write(tup, lcr, UART_LCR);
tegra_uart_write(tup, divisor & 0xFF, UART_TX);
tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER);
lcr &= ~UART_LCR_DLAB;
tegra_uart_write(tup, lcr, UART_LCR);
/* Dummy read to ensure the write is posted */
tegra_uart_read(tup, UART_SCR);
tup->current_baud = baud;
/* wait two character intervals at new rate */
tegra_uart_wait_sym_time(tup, 2);
return 0;
}
static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup,
unsigned int bytes)
{
if (bytes > TEGRA_UART_MIN_DMA)
bytes = TEGRA_UART_MIN_DMA;
tup->tx_in_progress = TEGRA_UART_TX_PIO;
tup->tx_bytes = bytes;
tup->ier_shadow |= UART_IER_THRI;
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
}
static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
unsigned long lcr;
lcr = tup->lcr_shadow;
if (break_ctl)
lcr |= UART_LCR_SBC;
else
lcr &= ~UART_LCR_SBC;
tegra_uart_write(tup, lcr, UART_LCR);
tup->lcr_shadow = lcr;
}
static void set_dtr(struct tegra_uart_port *tup, bool active)
{
unsigned long mcr;
mcr = tup->mcr_shadow;
if (active)
mcr |= UART_MCR_DTR;
else
mcr &= ~UART_MCR_DTR;
if (mcr != tup->mcr_shadow) {
tegra_uart_write(tup, mcr, UART_MCR);
tup->mcr_shadow = mcr;
}
}
static void set_rts(struct tegra_uart_port *tup, bool active)
{
unsigned long mcr;
mcr = tup->mcr_shadow;
if (active)
mcr |= TEGRA_UART_MCR_RTS_EN;
else
mcr &= ~TEGRA_UART_MCR_RTS_EN;
if (mcr != tup->mcr_shadow) {
tegra_uart_write(tup, mcr, UART_MCR);
tup->mcr_shadow = mcr;
}
}
static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
{
unsigned long fcr = tup->fcr_shadow;
if (tup->cdata->allow_txfifo_reset_fifo_mode) {
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
tegra_uart_write(tup, fcr, UART_FCR);
} else {
fcr &= ~UART_FCR_ENABLE_FIFO;
tegra_uart_write(tup, fcr, UART_FCR);
udelay(60);
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
tegra_uart_write(tup, fcr, UART_FCR);
fcr |= UART_FCR_ENABLE_FIFO;
tegra_uart_write(tup, fcr, UART_FCR);
}
/* Dummy read to ensure the write is posted */
tegra_uart_read(tup, UART_SCR);
/* Wait for the flush to propagate. */
tegra_uart_wait_sym_time(tup, 1);
}
static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
{
unsigned long flags;
unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud);
unsigned long fifo_empty_time = tup->uport.fifosize * char_time;
unsigned long wait_time;
unsigned long lsr;
unsigned long msr;
unsigned long mcr;
/* Disable interrupts */
tegra_uart_write(tup, 0, UART_IER);
lsr = tegra_uart_read(tup, UART_LSR);
if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
msr = tegra_uart_read(tup, UART_MSR);
mcr = tegra_uart_read(tup, UART_MCR);
if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS))
dev_err(tup->uport.dev,
"Tx Fifo not empty, CTS disabled, waiting\n");
/* 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 = tegra_uart_read(tup, UART_MSR);
mcr = tegra_uart_read(tup, UART_MCR);
if ((mcr & TEGRA_UART_MCR_CTS_EN) &&
(msr & UART_MSR_CTS))
dev_err(tup->uport.dev,
"Slave not ready\n");
break;
}
lsr = tegra_uart_read(tup, UART_LSR);
}
}
spin_lock_irqsave(&tup->uport.lock, flags);
/* Reset the Rx and Tx FIFOs */
tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
tup->current_baud = 0;
spin_unlock_irqrestore(&tup->uport.lock, flags);
clk_disable_unprepare(tup->uart_clk);
}
static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes)
{
struct circ_buf *xmit = &tup->uport.state->xmit;
int i;
for (i = 0; i < max_bytes; i++) {
BUG_ON(uart_circ_empty(xmit));
if (tup->cdata->tx_fifo_full_status) {
unsigned long lsr = tegra_uart_read(tup, UART_LSR);
if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL))
break;
}
tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
tup->uport.icount.tx++;
}
}
static void tegra_uart_stop_rx(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
struct tty_struct *tty;
struct tty_port *port = &u->state->port;
struct dma_tx_state state;
unsigned long ier;
int count;
if (tup->rts_active)
set_rts(tup, false);
if (!tup->rx_in_progress)
return;
tty = tty_port_tty_get(&tup->uport.state->port);
tegra_uart_wait_sym_time(tup, 1); /* wait a character interval */
ier = tup->ier_shadow;
ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
TEGRA_UART_IER_EORD);
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
tup->rx_in_progress = 0;
if (tup->rx_dma_chan && !tup->use_rx_pio) {
dmaengine_terminate_all(tup->rx_dma_chan);
dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
async_tx_ack(tup->rx_dma_desc);
count = tup->rx_bytes_requested - state.residue;
if (count)
tegra_uart_copy_rx_to_tty(tup, port, count);
tegra_uart_handle_rx_pio(tup, port);
} else {
tegra_uart_handle_rx_pio(tup, port);
}
if (tty) {
tty_flip_buffer_push(port);
tty_kref_put(tty);
}
return;
}
static void tegra_uart_stop_rx(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
struct dma_tx_state state;
unsigned long ier;
if (tup->rts_active)
set_rts(tup, false);
if (!tup->rx_in_progress)
return;
tegra_uart_wait_sym_time(tup, 1); /* wait a character interval */
ier = tup->ier_shadow;
ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
TEGRA_UART_IER_EORD);
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
tup->rx_in_progress = 0;
dmaengine_terminate_all(tup->rx_dma_chan);
dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
tegra_uart_rx_buffer_push(tup, state.residue);
}
static int tegra_uart_hw_init(struct tegra_uart_port *tup)
{
int ret;
tup->fcr_shadow = 0;
tup->mcr_shadow = 0;
tup->lcr_shadow = 0;
tup->ier_shadow = 0;
tup->current_baud = 0;
clk_prepare_enable(tup->uart_clk);
/* Reset the UART controller to clear all previous status.*/
reset_control_assert(tup->rst);
udelay(10);
reset_control_deassert(tup->rst);
tup->rx_in_progress = 0;
tup->tx_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 16 bytes.
*
* For DMA mode:
*
* Set the Tx trigger to 16. This should match the DMA burst size that
* programmed in the DMA registers.
*/
tup->fcr_shadow = UART_FCR_ENABLE_FIFO;
tup->fcr_shadow |= UART_FCR_R_TRIG_01;
tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B;
tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
/* Dummy read to ensure the write is posted */
tegra_uart_read(tup, UART_SCR);
/*
* For all tegra devices (up to t210), there is a hardware issue that
* requires software to wait for 3 UART clock periods after enabling
* the TX fifo, otherwise data could be lost.
*/
tegra_uart_wait_cycle_time(tup, 3);
/*
* Initialize the UART with default configuration
* (115200, N, 8, 1) so that the receive DMA buffer may be
* enqueued
*/
tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR;
tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD);
tup->fcr_shadow |= UART_FCR_DMA_SELECT;
tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
ret = tegra_uart_start_rx_dma(tup);
if (ret < 0) {
dev_err(tup->uport.dev, "Not able to start Rx DMA\n");
return ret;
}
tup->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.
*/
tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | TEGRA_UART_IER_EORD;
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
return 0;
}
static irqreturn_t tegra_uart_isr(int irq, void *data)
{
struct tegra_uart_port *tup = data;
struct uart_port *u = &tup->uport;
unsigned long iir;
unsigned long ier;
bool is_rx_int = false;
unsigned long flags;
spin_lock_irqsave(&u->lock, flags);
while (1) {
iir = tegra_uart_read(tup, UART_IIR);
if (iir & UART_IIR_NO_INT) {
if (is_rx_int) {
tegra_uart_handle_rx_dma(tup);
if (tup->rx_in_progress) {
ier = tup->ier_shadow;
ier |= (UART_IER_RLSI | UART_IER_RTOIE |
TEGRA_UART_IER_EORD);
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
}
}
spin_unlock_irqrestore(&u->lock, flags);
return IRQ_HANDLED;
}
switch ((iir >> 1) & 0x7) {
case 0: /* Modem signal change interrupt */
tegra_uart_handle_modem_signal_change(u);
break;
case 1: /* Transmit interrupt only triggered when using PIO */
tup->ier_shadow &= ~UART_IER_THRI;
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
tegra_uart_handle_tx_pio(tup);
break;
case 4: /* End of data */
case 6: /* Rx timeout */
case 2: /* Receive */
if (!is_rx_int) {
is_rx_int = true;
/* Disable Rx interrupts */
ier = tup->ier_shadow;
ier |= UART_IER_RDI;
tegra_uart_write(tup, ier, UART_IER);
ier &= ~(UART_IER_RDI | UART_IER_RLSI |
UART_IER_RTOIE | TEGRA_UART_IER_EORD);
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
}
break;
case 3: /* Receive error */
tegra_uart_decode_rx_error(tup,
tegra_uart_read(tup, UART_LSR));
break;
case 5: /* break nothing to handle */
case 7: /* break nothing to handle */
break;
}
}
}
static void tegra_uart_set_termios(struct uart_port *u,
struct ktermios *termios, struct ktermios *oldtermios)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
unsigned int baud;
unsigned long flags;
unsigned int lcr;
int symb_bit = 1;
struct clk *parent_clk = clk_get_parent(tup->uart_clk);
unsigned long parent_clk_rate = clk_get_rate(parent_clk);
int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF;
max_divider *= 16;
spin_lock_irqsave(&u->lock, flags);
/* Changing configuration, it is safe to stop any rx now */
if (tup->rts_active)
set_rts(tup, false);
/* Clear all interrupts as configuration is going to be change */
tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER);
tegra_uart_read(tup, UART_IER);
tegra_uart_write(tup, 0, UART_IER);
tegra_uart_read(tup, UART_IER);
/* Parity */
lcr = tup->lcr_shadow;
lcr &= ~UART_LCR_PARITY;
/* CMSPAR isn't supported by this driver */
termios->c_cflag &= ~CMSPAR;
if ((termios->c_cflag & PARENB) == PARENB) {
symb_bit++;
if (termios->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 (termios->c_cflag & CSIZE) {
case CS5:
lcr |= UART_LCR_WLEN5;
symb_bit += 5;
break;
case CS6:
lcr |= UART_LCR_WLEN6;
symb_bit += 6;
break;
case CS7:
lcr |= UART_LCR_WLEN7;
symb_bit += 7;
break;
default:
lcr |= UART_LCR_WLEN8;
symb_bit += 8;
break;
}
/* Stop bits */
if (termios->c_cflag & CSTOPB) {
lcr |= UART_LCR_STOP;
symb_bit += 2;
} else {
lcr &= ~UART_LCR_STOP;
symb_bit++;
}
tegra_uart_write(tup, lcr, UART_LCR);
tup->lcr_shadow = lcr;
tup->symb_bit = symb_bit;
/* Baud rate. */
baud = uart_get_baud_rate(u, termios, oldtermios,
parent_clk_rate/max_divider,
parent_clk_rate/16);
spin_unlock_irqrestore(&u->lock, flags);
tegra_set_baudrate(tup, baud);
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);
spin_lock_irqsave(&u->lock, flags);
/* Flow control */
if (termios->c_cflag & CRTSCTS) {
tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN;
tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
/* if top layer has asked to set rts active then do so here */
if (tup->rts_active)
set_rts(tup, true);
} else {
tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN;
tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
}
/* update the port timeout based on new settings */
uart_update_timeout(u, termios->c_cflag, baud);
/* Make sure all write has completed */
tegra_uart_read(tup, UART_IER);
/* Reenable interrupt */
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
tegra_uart_read(tup, UART_IER);
spin_unlock_irqrestore(&u->lock, flags);
}
