4 * High-speed serial driver for NVIDIA Tegra SoCs
6 * Copyright (c) 2012-2013, NVIDIA CORPORATION. All rights reserved.
8 * Author: Laxman Dewangan <ldewangan@nvidia.com>
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms and conditions of the GNU General Public License,
12 * version 2, as published by the Free Software Foundation.
14 * This program is distributed in the hope it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19 * You should have received a copy of the GNU General Public License
20 * along with this program. If not, see <http://www.gnu.org/licenses/>.
23 #include <linux/clk.h>
24 #include <linux/debugfs.h>
25 #include <linux/delay.h>
26 #include <linux/dmaengine.h>
27 #include <linux/dma-mapping.h>
28 #include <linux/dmapool.h>
29 #include <linux/err.h>
31 #include <linux/irq.h>
32 #include <linux/module.h>
34 #include <linux/of_device.h>
35 #include <linux/pagemap.h>
36 #include <linux/platform_device.h>
37 #include <linux/serial.h>
38 #include <linux/serial_8250.h>
39 #include <linux/serial_core.h>
40 #include <linux/serial_reg.h>
41 #include <linux/slab.h>
42 #include <linux/string.h>
43 #include <linux/termios.h>
44 #include <linux/tty.h>
45 #include <linux/tty_flip.h>
47 #include <linux/clk/tegra.h>
49 #define TEGRA_UART_TYPE "TEGRA_UART"
50 #define TX_EMPTY_STATUS (UART_LSR_TEMT | UART_LSR_THRE)
51 #define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3)
53 #define TEGRA_UART_RX_DMA_BUFFER_SIZE 4096
54 #define TEGRA_UART_LSR_TXFIFO_FULL 0x100
55 #define TEGRA_UART_IER_EORD 0x20
56 #define TEGRA_UART_MCR_RTS_EN 0x40
57 #define TEGRA_UART_MCR_CTS_EN 0x20
58 #define TEGRA_UART_LSR_ANY (UART_LSR_OE | UART_LSR_BI | \
59 UART_LSR_PE | UART_LSR_FE)
60 #define TEGRA_UART_IRDA_CSR 0x08
61 #define TEGRA_UART_SIR_ENABLED 0x80
63 #define TEGRA_UART_TX_PIO 1
64 #define TEGRA_UART_TX_DMA 2
65 #define TEGRA_UART_MIN_DMA 16
66 #define TEGRA_UART_FIFO_SIZE 32
69 * Tx fifo trigger level setting in tegra uart is in
70 * reverse way then conventional uart.
72 #define TEGRA_UART_TX_TRIG_16B 0x00
73 #define TEGRA_UART_TX_TRIG_8B 0x10
74 #define TEGRA_UART_TX_TRIG_4B 0x20
75 #define TEGRA_UART_TX_TRIG_1B 0x30
77 #define TEGRA_UART_MAXIMUM 5
79 /* Default UART setting when started: 115200 no parity, stop, 8 data bits */
80 #define TEGRA_UART_DEFAULT_BAUD 115200
81 #define TEGRA_UART_DEFAULT_LSR UART_LCR_WLEN8
83 /* Tx transfer mode */
84 #define TEGRA_TX_PIO 1
85 #define TEGRA_TX_DMA 2
88 * tegra_uart_chip_data: SOC specific data.
90 * @tx_fifo_full_status: Status flag available for checking tx fifo full.
91 * @allow_txfifo_reset_fifo_mode: allow_tx fifo reset with fifo mode or not.
92 * Tegra30 does not allow this.
93 * @support_clk_src_div: Clock source support the clock divider.
95 struct tegra_uart_chip_data {
96 bool tx_fifo_full_status;
97 bool allow_txfifo_reset_fifo_mode;
98 bool support_clk_src_div;
101 struct tegra_uart_port {
102 struct uart_port uport;
103 const struct tegra_uart_chip_data *cdata;
105 struct clk *uart_clk;
106 unsigned int current_baud;
108 /* Register shadow */
109 unsigned long fcr_shadow;
110 unsigned long mcr_shadow;
111 unsigned long lcr_shadow;
112 unsigned long ier_shadow;
116 unsigned int tx_bytes;
118 bool enable_modem_interrupt;
125 struct dma_chan *rx_dma_chan;
126 struct dma_chan *tx_dma_chan;
127 dma_addr_t rx_dma_buf_phys;
128 dma_addr_t tx_dma_buf_phys;
129 unsigned char *rx_dma_buf_virt;
130 unsigned char *tx_dma_buf_virt;
131 struct dma_async_tx_descriptor *tx_dma_desc;
132 struct dma_async_tx_descriptor *rx_dma_desc;
133 dma_cookie_t tx_cookie;
134 dma_cookie_t rx_cookie;
135 int tx_bytes_requested;
136 int rx_bytes_requested;
139 static void tegra_uart_start_next_tx(struct tegra_uart_port *tup);
140 static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup);
142 static inline unsigned long tegra_uart_read(struct tegra_uart_port *tup,
145 return readl(tup->uport.membase + (reg << tup->uport.regshift));
148 static inline void tegra_uart_write(struct tegra_uart_port *tup, unsigned val,
151 writel(val, tup->uport.membase + (reg << tup->uport.regshift));
154 static inline struct tegra_uart_port *to_tegra_uport(struct uart_port *u)
156 return container_of(u, struct tegra_uart_port, uport);
159 static unsigned int tegra_uart_get_mctrl(struct uart_port *u)
161 struct tegra_uart_port *tup = to_tegra_uport(u);
164 * RI - Ring detector is active
165 * CD/DCD/CAR - Carrier detect is always active. For some reason
166 * linux has different names for carrier detect.
167 * DSR - Data Set ready is active as the hardware doesn't support it.
168 * Don't know if the linux support this yet?
169 * CTS - Clear to send. Always set to active, as the hardware handles
172 if (tup->enable_modem_interrupt)
173 return TIOCM_RI | TIOCM_CD | TIOCM_DSR | TIOCM_CTS;
177 static void set_rts(struct tegra_uart_port *tup, bool active)
181 mcr = tup->mcr_shadow;
183 mcr |= TEGRA_UART_MCR_RTS_EN;
185 mcr &= ~TEGRA_UART_MCR_RTS_EN;
186 if (mcr != tup->mcr_shadow) {
187 tegra_uart_write(tup, mcr, UART_MCR);
188 tup->mcr_shadow = mcr;
193 static void set_dtr(struct tegra_uart_port *tup, bool active)
197 mcr = tup->mcr_shadow;
201 mcr &= ~UART_MCR_DTR;
202 if (mcr != tup->mcr_shadow) {
203 tegra_uart_write(tup, mcr, UART_MCR);
204 tup->mcr_shadow = mcr;
209 static void tegra_uart_set_mctrl(struct uart_port *u, unsigned int mctrl)
211 struct tegra_uart_port *tup = to_tegra_uport(u);
215 mcr = tup->mcr_shadow;
216 tup->rts_active = !!(mctrl & TIOCM_RTS);
217 set_rts(tup, tup->rts_active);
219 dtr_enable = !!(mctrl & TIOCM_DTR);
220 set_dtr(tup, dtr_enable);
224 static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl)
226 struct tegra_uart_port *tup = to_tegra_uport(u);
229 lcr = tup->lcr_shadow;
233 lcr &= ~UART_LCR_SBC;
234 tegra_uart_write(tup, lcr, UART_LCR);
235 tup->lcr_shadow = lcr;
238 /* Wait for a symbol-time. */
239 static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup,
242 if (tup->current_baud)
243 udelay(DIV_ROUND_UP(syms * tup->symb_bit * 1000000,
247 static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
249 unsigned long fcr = tup->fcr_shadow;
251 if (tup->cdata->allow_txfifo_reset_fifo_mode) {
252 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
253 tegra_uart_write(tup, fcr, UART_FCR);
255 fcr &= ~UART_FCR_ENABLE_FIFO;
256 tegra_uart_write(tup, fcr, UART_FCR);
258 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
259 tegra_uart_write(tup, fcr, UART_FCR);
260 fcr |= UART_FCR_ENABLE_FIFO;
261 tegra_uart_write(tup, fcr, UART_FCR);
264 /* Dummy read to ensure the write is posted */
265 tegra_uart_read(tup, UART_SCR);
267 /* Wait for the flush to propagate. */
268 tegra_uart_wait_sym_time(tup, 1);
271 static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
274 unsigned int divisor;
278 if (tup->current_baud == baud)
281 if (tup->cdata->support_clk_src_div) {
283 ret = clk_set_rate(tup->uart_clk, rate);
285 dev_err(tup->uport.dev,
286 "clk_set_rate() failed for rate %lu\n", rate);
291 rate = clk_get_rate(tup->uart_clk);
292 divisor = DIV_ROUND_CLOSEST(rate, baud * 16);
295 lcr = tup->lcr_shadow;
296 lcr |= UART_LCR_DLAB;
297 tegra_uart_write(tup, lcr, UART_LCR);
299 tegra_uart_write(tup, divisor & 0xFF, UART_TX);
300 tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER);
302 lcr &= ~UART_LCR_DLAB;
303 tegra_uart_write(tup, lcr, UART_LCR);
305 /* Dummy read to ensure the write is posted */
306 tegra_uart_read(tup, UART_SCR);
308 tup->current_baud = baud;
310 /* wait two character intervals at new rate */
311 tegra_uart_wait_sym_time(tup, 2);
315 static char tegra_uart_decode_rx_error(struct tegra_uart_port *tup,
318 char flag = TTY_NORMAL;
320 if (unlikely(lsr & TEGRA_UART_LSR_ANY)) {
321 if (lsr & UART_LSR_OE) {
324 tup->uport.icount.overrun++;
325 dev_err(tup->uport.dev, "Got overrun errors\n");
326 } else if (lsr & UART_LSR_PE) {
329 tup->uport.icount.parity++;
330 dev_err(tup->uport.dev, "Got Parity errors\n");
331 } else if (lsr & UART_LSR_FE) {
333 tup->uport.icount.frame++;
334 dev_err(tup->uport.dev, "Got frame errors\n");
335 } else if (lsr & UART_LSR_BI) {
336 dev_err(tup->uport.dev, "Got Break\n");
337 tup->uport.icount.brk++;
338 /* If FIFO read error without any data, reset Rx FIFO */
339 if (!(lsr & UART_LSR_DR) && (lsr & UART_LSR_FIFOE))
340 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_RCVR);
346 static int tegra_uart_request_port(struct uart_port *u)
351 static void tegra_uart_release_port(struct uart_port *u)
353 /* Nothing to do here */
356 static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes)
358 struct circ_buf *xmit = &tup->uport.state->xmit;
361 for (i = 0; i < max_bytes; i++) {
362 BUG_ON(uart_circ_empty(xmit));
363 if (tup->cdata->tx_fifo_full_status) {
364 unsigned long lsr = tegra_uart_read(tup, UART_LSR);
365 if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL))
368 tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX);
369 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
370 tup->uport.icount.tx++;
374 static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup,
377 if (bytes > TEGRA_UART_MIN_DMA)
378 bytes = TEGRA_UART_MIN_DMA;
380 tup->tx_in_progress = TEGRA_UART_TX_PIO;
381 tup->tx_bytes = bytes;
382 tup->ier_shadow |= UART_IER_THRI;
383 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
386 static void tegra_uart_tx_dma_complete(void *args)
388 struct tegra_uart_port *tup = args;
389 struct circ_buf *xmit = &tup->uport.state->xmit;
390 struct dma_tx_state state;
394 dmaengine_tx_status(tup->tx_dma_chan, tup->rx_cookie, &state);
395 count = tup->tx_bytes_requested - state.residue;
396 async_tx_ack(tup->tx_dma_desc);
397 spin_lock_irqsave(&tup->uport.lock, flags);
398 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
399 tup->tx_in_progress = 0;
400 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
401 uart_write_wakeup(&tup->uport);
402 tegra_uart_start_next_tx(tup);
403 spin_unlock_irqrestore(&tup->uport.lock, flags);
406 static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup,
409 struct circ_buf *xmit = &tup->uport.state->xmit;
410 dma_addr_t tx_phys_addr;
412 dma_sync_single_for_device(tup->uport.dev, tup->tx_dma_buf_phys,
413 UART_XMIT_SIZE, DMA_TO_DEVICE);
415 tup->tx_bytes = count & ~(0xF);
416 tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail;
417 tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan,
418 tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV,
420 if (!tup->tx_dma_desc) {
421 dev_err(tup->uport.dev, "Not able to get desc for Tx\n");
425 tup->tx_dma_desc->callback = tegra_uart_tx_dma_complete;
426 tup->tx_dma_desc->callback_param = tup;
427 tup->tx_in_progress = TEGRA_UART_TX_DMA;
428 tup->tx_bytes_requested = tup->tx_bytes;
429 tup->tx_cookie = dmaengine_submit(tup->tx_dma_desc);
430 dma_async_issue_pending(tup->tx_dma_chan);
434 static void tegra_uart_start_next_tx(struct tegra_uart_port *tup)
438 struct circ_buf *xmit = &tup->uport.state->xmit;
440 tail = (unsigned long)&xmit->buf[xmit->tail];
441 count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
445 if (count < TEGRA_UART_MIN_DMA)
446 tegra_uart_start_pio_tx(tup, count);
447 else if (BYTES_TO_ALIGN(tail) > 0)
448 tegra_uart_start_pio_tx(tup, BYTES_TO_ALIGN(tail));
450 tegra_uart_start_tx_dma(tup, count);
453 /* Called by serial core driver with u->lock taken. */
454 static void tegra_uart_start_tx(struct uart_port *u)
456 struct tegra_uart_port *tup = to_tegra_uport(u);
457 struct circ_buf *xmit = &u->state->xmit;
459 if (!uart_circ_empty(xmit) && !tup->tx_in_progress)
460 tegra_uart_start_next_tx(tup);
463 static unsigned int tegra_uart_tx_empty(struct uart_port *u)
465 struct tegra_uart_port *tup = to_tegra_uport(u);
466 unsigned int ret = 0;
469 spin_lock_irqsave(&u->lock, flags);
470 if (!tup->tx_in_progress) {
471 unsigned long lsr = tegra_uart_read(tup, UART_LSR);
472 if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS)
475 spin_unlock_irqrestore(&u->lock, flags);
479 static void tegra_uart_stop_tx(struct uart_port *u)
481 struct tegra_uart_port *tup = to_tegra_uport(u);
482 struct circ_buf *xmit = &tup->uport.state->xmit;
483 struct dma_tx_state state;
486 dmaengine_terminate_all(tup->tx_dma_chan);
487 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
488 count = tup->tx_bytes_requested - state.residue;
489 async_tx_ack(tup->tx_dma_desc);
490 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
491 tup->tx_in_progress = 0;
495 static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup)
497 struct circ_buf *xmit = &tup->uport.state->xmit;
499 tegra_uart_fill_tx_fifo(tup, tup->tx_bytes);
500 tup->tx_in_progress = 0;
501 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
502 uart_write_wakeup(&tup->uport);
503 tegra_uart_start_next_tx(tup);
507 static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup,
508 struct tty_port *tty)
511 char flag = TTY_NORMAL;
512 unsigned long lsr = 0;
515 lsr = tegra_uart_read(tup, UART_LSR);
516 if (!(lsr & UART_LSR_DR))
519 flag = tegra_uart_decode_rx_error(tup, lsr);
520 ch = (unsigned char) tegra_uart_read(tup, UART_RX);
521 tup->uport.icount.rx++;
523 if (!uart_handle_sysrq_char(&tup->uport, ch) && tty)
524 tty_insert_flip_char(tty, ch, flag);
530 static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup,
531 struct tty_port *tty, int count)
535 tup->uport.icount.rx += count;
537 dev_err(tup->uport.dev, "No tty port\n");
540 dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys,
541 TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
542 copied = tty_insert_flip_string(tty,
543 ((unsigned char *)(tup->rx_dma_buf_virt)), count);
544 if (copied != count) {
546 dev_err(tup->uport.dev, "RxData copy to tty layer failed\n");
548 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
549 TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
552 static void tegra_uart_rx_dma_complete(void *args)
554 struct tegra_uart_port *tup = args;
555 struct uart_port *u = &tup->uport;
556 int count = tup->rx_bytes_requested;
557 struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port);
558 struct tty_port *port = &u->state->port;
561 async_tx_ack(tup->rx_dma_desc);
562 spin_lock_irqsave(&u->lock, flags);
564 /* Deactivate flow control to stop sender */
568 /* If we are here, DMA is stopped */
570 tegra_uart_copy_rx_to_tty(tup, port, count);
572 tegra_uart_handle_rx_pio(tup, port);
574 tty_flip_buffer_push(port);
577 tegra_uart_start_rx_dma(tup);
579 /* Activate flow control to start transfer */
583 spin_unlock_irqrestore(&u->lock, flags);
586 static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
588 struct dma_tx_state state;
589 struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port);
590 struct tty_port *port = &tup->uport.state->port;
593 /* Deactivate flow control to stop sender */
597 dmaengine_terminate_all(tup->rx_dma_chan);
598 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
599 count = tup->rx_bytes_requested - state.residue;
601 /* If we are here, DMA is stopped */
603 tegra_uart_copy_rx_to_tty(tup, port, count);
605 tegra_uart_handle_rx_pio(tup, port);
607 tty_flip_buffer_push(port);
610 tegra_uart_start_rx_dma(tup);
616 static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup)
618 unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE;
620 tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan,
621 tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM,
623 if (!tup->rx_dma_desc) {
624 dev_err(tup->uport.dev, "Not able to get desc for Rx\n");
628 tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete;
629 tup->rx_dma_desc->callback_param = tup;
630 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
631 count, DMA_TO_DEVICE);
632 tup->rx_bytes_requested = count;
633 tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc);
634 dma_async_issue_pending(tup->rx_dma_chan);
638 static void tegra_uart_handle_modem_signal_change(struct uart_port *u)
640 struct tegra_uart_port *tup = to_tegra_uport(u);
643 msr = tegra_uart_read(tup, UART_MSR);
644 if (!(msr & UART_MSR_ANY_DELTA))
647 if (msr & UART_MSR_TERI)
648 tup->uport.icount.rng++;
649 if (msr & UART_MSR_DDSR)
650 tup->uport.icount.dsr++;
651 /* We may only get DDCD when HW init and reset */
652 if (msr & UART_MSR_DDCD)
653 uart_handle_dcd_change(&tup->uport, msr & UART_MSR_DCD);
654 /* Will start/stop_tx accordingly */
655 if (msr & UART_MSR_DCTS)
656 uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS);
660 static irqreturn_t tegra_uart_isr(int irq, void *data)
662 struct tegra_uart_port *tup = data;
663 struct uart_port *u = &tup->uport;
666 bool is_rx_int = false;
669 spin_lock_irqsave(&u->lock, flags);
671 iir = tegra_uart_read(tup, UART_IIR);
672 if (iir & UART_IIR_NO_INT) {
674 tegra_uart_handle_rx_dma(tup);
675 if (tup->rx_in_progress) {
676 ier = tup->ier_shadow;
677 ier |= (UART_IER_RLSI | UART_IER_RTOIE |
678 TEGRA_UART_IER_EORD);
679 tup->ier_shadow = ier;
680 tegra_uart_write(tup, ier, UART_IER);
683 spin_unlock_irqrestore(&u->lock, flags);
687 switch ((iir >> 1) & 0x7) {
688 case 0: /* Modem signal change interrupt */
689 tegra_uart_handle_modem_signal_change(u);
692 case 1: /* Transmit interrupt only triggered when using PIO */
693 tup->ier_shadow &= ~UART_IER_THRI;
694 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
695 tegra_uart_handle_tx_pio(tup);
698 case 4: /* End of data */
699 case 6: /* Rx timeout */
700 case 2: /* Receive */
703 /* Disable Rx interrupts */
704 ier = tup->ier_shadow;
706 tegra_uart_write(tup, ier, UART_IER);
707 ier &= ~(UART_IER_RDI | UART_IER_RLSI |
708 UART_IER_RTOIE | TEGRA_UART_IER_EORD);
709 tup->ier_shadow = ier;
710 tegra_uart_write(tup, ier, UART_IER);
714 case 3: /* Receive error */
715 tegra_uart_decode_rx_error(tup,
716 tegra_uart_read(tup, UART_LSR));
719 case 5: /* break nothing to handle */
720 case 7: /* break nothing to handle */
726 static void tegra_uart_stop_rx(struct uart_port *u)
728 struct tegra_uart_port *tup = to_tegra_uport(u);
729 struct tty_struct *tty;
730 struct tty_port *port = &u->state->port;
731 struct dma_tx_state state;
738 if (!tup->rx_in_progress)
741 tty = tty_port_tty_get(&tup->uport.state->port);
743 tegra_uart_wait_sym_time(tup, 1); /* wait a character interval */
745 ier = tup->ier_shadow;
746 ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
747 TEGRA_UART_IER_EORD);
748 tup->ier_shadow = ier;
749 tegra_uart_write(tup, ier, UART_IER);
750 tup->rx_in_progress = 0;
751 if (tup->rx_dma_chan) {
752 dmaengine_terminate_all(tup->rx_dma_chan);
753 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
754 async_tx_ack(tup->rx_dma_desc);
755 count = tup->rx_bytes_requested - state.residue;
756 tegra_uart_copy_rx_to_tty(tup, port, count);
757 tegra_uart_handle_rx_pio(tup, port);
759 tegra_uart_handle_rx_pio(tup, port);
762 tty_flip_buffer_push(port);
768 static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
771 unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud);
772 unsigned long fifo_empty_time = tup->uport.fifosize * char_time;
773 unsigned long wait_time;
778 /* Disable interrupts */
779 tegra_uart_write(tup, 0, UART_IER);
781 lsr = tegra_uart_read(tup, UART_LSR);
782 if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
783 msr = tegra_uart_read(tup, UART_MSR);
784 mcr = tegra_uart_read(tup, UART_MCR);
785 if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS))
786 dev_err(tup->uport.dev,
787 "Tx Fifo not empty, CTS disabled, waiting\n");
789 /* Wait for Tx fifo to be empty */
790 while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
791 wait_time = min(fifo_empty_time, 100lu);
793 fifo_empty_time -= wait_time;
794 if (!fifo_empty_time) {
795 msr = tegra_uart_read(tup, UART_MSR);
796 mcr = tegra_uart_read(tup, UART_MCR);
797 if ((mcr & TEGRA_UART_MCR_CTS_EN) &&
798 (msr & UART_MSR_CTS))
799 dev_err(tup->uport.dev,
800 "Slave not ready\n");
803 lsr = tegra_uart_read(tup, UART_LSR);
807 spin_lock_irqsave(&tup->uport.lock, flags);
808 /* Reset the Rx and Tx FIFOs */
809 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
810 tup->current_baud = 0;
811 spin_unlock_irqrestore(&tup->uport.lock, flags);
813 clk_disable_unprepare(tup->uart_clk);
816 static int tegra_uart_hw_init(struct tegra_uart_port *tup)
824 tup->current_baud = 0;
826 clk_prepare_enable(tup->uart_clk);
828 /* Reset the UART controller to clear all previous status.*/
829 tegra_periph_reset_assert(tup->uart_clk);
831 tegra_periph_reset_deassert(tup->uart_clk);
833 tup->rx_in_progress = 0;
834 tup->tx_in_progress = 0;
837 * Set the trigger level
841 * For receive, this will interrupt the CPU after that many number of
842 * bytes are received, for the remaining bytes the receive timeout
843 * interrupt is received. Rx high watermark is set to 4.
845 * For transmit, if the trasnmit interrupt is enabled, this will
846 * interrupt the CPU when the number of entries in the FIFO reaches the
847 * low watermark. Tx low watermark is set to 16 bytes.
851 * Set the Tx trigger to 16. This should match the DMA burst size that
852 * programmed in the DMA registers.
854 tup->fcr_shadow = UART_FCR_ENABLE_FIFO;
855 tup->fcr_shadow |= UART_FCR_R_TRIG_01;
856 tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B;
857 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
860 * Initialize the UART with default configuration
861 * (115200, N, 8, 1) so that the receive DMA buffer may be
864 tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR;
865 tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD);
866 tup->fcr_shadow |= UART_FCR_DMA_SELECT;
867 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
869 ret = tegra_uart_start_rx_dma(tup);
871 dev_err(tup->uport.dev, "Not able to start Rx DMA\n");
874 tup->rx_in_progress = 1;
877 * Enable IE_RXS for the receive status interrupts like line errros.
878 * Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd.
880 * If using DMA mode, enable EORD instead of receive interrupt which
881 * will interrupt after the UART is done with the receive instead of
882 * the interrupt when the FIFO "threshold" is reached.
884 * EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when
885 * the DATA is sitting in the FIFO and couldn't be transferred to the
886 * DMA as the DMA size alignment(4 bytes) is not met. EORD will be
887 * triggered when there is a pause of the incomming data stream for 4
890 * For pauses in the data which is not aligned to 4 bytes, we get
891 * both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first
894 tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | TEGRA_UART_IER_EORD;
895 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
899 static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
902 struct dma_chan *dma_chan;
903 unsigned char *dma_buf;
906 struct dma_slave_config dma_sconfig;
910 dma_cap_set(DMA_SLAVE, mask);
911 dma_chan = dma_request_channel(mask, NULL, NULL);
913 dev_err(tup->uport.dev,
914 "Dma channel is not available, will try later\n");
915 return -EPROBE_DEFER;
919 dma_buf = dma_alloc_coherent(tup->uport.dev,
920 TEGRA_UART_RX_DMA_BUFFER_SIZE,
921 &dma_phys, GFP_KERNEL);
923 dev_err(tup->uport.dev,
924 "Not able to allocate the dma buffer\n");
925 dma_release_channel(dma_chan);
929 dma_phys = dma_map_single(tup->uport.dev,
930 tup->uport.state->xmit.buf, UART_XMIT_SIZE,
932 dma_buf = tup->uport.state->xmit.buf;
935 dma_sconfig.slave_id = tup->dma_req_sel;
937 dma_sconfig.src_addr = tup->uport.mapbase;
938 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
939 dma_sconfig.src_maxburst = 4;
941 dma_sconfig.dst_addr = tup->uport.mapbase;
942 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
943 dma_sconfig.dst_maxburst = 16;
946 ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
948 dev_err(tup->uport.dev,
949 "Dma slave config failed, err = %d\n", ret);
954 tup->rx_dma_chan = dma_chan;
955 tup->rx_dma_buf_virt = dma_buf;
956 tup->rx_dma_buf_phys = dma_phys;
958 tup->tx_dma_chan = dma_chan;
959 tup->tx_dma_buf_virt = dma_buf;
960 tup->tx_dma_buf_phys = dma_phys;
965 dma_release_channel(dma_chan);
969 static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
972 struct dma_chan *dma_chan;
975 dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,
976 tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);
977 dma_chan = tup->rx_dma_chan;
978 tup->rx_dma_chan = NULL;
979 tup->rx_dma_buf_phys = 0;
980 tup->rx_dma_buf_virt = NULL;
982 dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,
983 UART_XMIT_SIZE, DMA_TO_DEVICE);
984 dma_chan = tup->tx_dma_chan;
985 tup->tx_dma_chan = NULL;
986 tup->tx_dma_buf_phys = 0;
987 tup->tx_dma_buf_virt = NULL;
989 dma_release_channel(dma_chan);
992 static int tegra_uart_startup(struct uart_port *u)
994 struct tegra_uart_port *tup = to_tegra_uport(u);
997 ret = tegra_uart_dma_channel_allocate(tup, false);
999 dev_err(u->dev, "Tx Dma allocation failed, err = %d\n", ret);
1003 ret = tegra_uart_dma_channel_allocate(tup, true);
1005 dev_err(u->dev, "Rx Dma allocation failed, err = %d\n", ret);
1009 ret = tegra_uart_hw_init(tup);
1011 dev_err(u->dev, "Uart HW init failed, err = %d\n", ret);
1015 ret = request_irq(u->irq, tegra_uart_isr, IRQF_DISABLED,
1016 dev_name(u->dev), tup);
1018 dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq);
1024 tegra_uart_dma_channel_free(tup, true);
1026 tegra_uart_dma_channel_free(tup, false);
1030 static void tegra_uart_shutdown(struct uart_port *u)
1032 struct tegra_uart_port *tup = to_tegra_uport(u);
1034 tegra_uart_hw_deinit(tup);
1036 tup->rx_in_progress = 0;
1037 tup->tx_in_progress = 0;
1039 tegra_uart_dma_channel_free(tup, true);
1040 tegra_uart_dma_channel_free(tup, false);
1041 free_irq(u->irq, tup);
1044 static void tegra_uart_enable_ms(struct uart_port *u)
1046 struct tegra_uart_port *tup = to_tegra_uport(u);
1048 if (tup->enable_modem_interrupt) {
1049 tup->ier_shadow |= UART_IER_MSI;
1050 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
1054 static void tegra_uart_set_termios(struct uart_port *u,
1055 struct ktermios *termios, struct ktermios *oldtermios)
1057 struct tegra_uart_port *tup = to_tegra_uport(u);
1059 unsigned long flags;
1062 struct clk *parent_clk = clk_get_parent(tup->uart_clk);
1063 unsigned long parent_clk_rate = clk_get_rate(parent_clk);
1064 int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF;
1067 spin_lock_irqsave(&u->lock, flags);
1069 /* Changing configuration, it is safe to stop any rx now */
1070 if (tup->rts_active)
1071 set_rts(tup, false);
1073 /* Clear all interrupts as configuration is going to be change */
1074 tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER);
1075 tegra_uart_read(tup, UART_IER);
1076 tegra_uart_write(tup, 0, UART_IER);
1077 tegra_uart_read(tup, UART_IER);
1080 lcr = tup->lcr_shadow;
1081 lcr &= ~UART_LCR_PARITY;
1083 /* CMSPAR isn't supported by this driver */
1084 termios->c_cflag &= ~CMSPAR;
1086 if ((termios->c_cflag & PARENB) == PARENB) {
1088 if (termios->c_cflag & PARODD) {
1089 lcr |= UART_LCR_PARITY;
1090 lcr &= ~UART_LCR_EPAR;
1091 lcr &= ~UART_LCR_SPAR;
1093 lcr |= UART_LCR_PARITY;
1094 lcr |= UART_LCR_EPAR;
1095 lcr &= ~UART_LCR_SPAR;
1099 lcr &= ~UART_LCR_WLEN8;
1100 switch (termios->c_cflag & CSIZE) {
1102 lcr |= UART_LCR_WLEN5;
1106 lcr |= UART_LCR_WLEN6;
1110 lcr |= UART_LCR_WLEN7;
1114 lcr |= UART_LCR_WLEN8;
1120 if (termios->c_cflag & CSTOPB) {
1121 lcr |= UART_LCR_STOP;
1124 lcr &= ~UART_LCR_STOP;
1128 tegra_uart_write(tup, lcr, UART_LCR);
1129 tup->lcr_shadow = lcr;
1130 tup->symb_bit = symb_bit;
1133 baud = uart_get_baud_rate(u, termios, oldtermios,
1134 parent_clk_rate/max_divider,
1135 parent_clk_rate/16);
1136 spin_unlock_irqrestore(&u->lock, flags);
1137 tegra_set_baudrate(tup, baud);
1138 if (tty_termios_baud_rate(termios))
1139 tty_termios_encode_baud_rate(termios, baud, baud);
1140 spin_lock_irqsave(&u->lock, flags);
1143 if (termios->c_cflag & CRTSCTS) {
1144 tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN;
1145 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
1146 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
1147 /* if top layer has asked to set rts active then do so here */
1148 if (tup->rts_active)
1151 tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN;
1152 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
1153 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
1156 /* update the port timeout based on new settings */
1157 uart_update_timeout(u, termios->c_cflag, baud);
1159 /* Make sure all write has completed */
1160 tegra_uart_read(tup, UART_IER);
1162 /* Reenable interrupt */
1163 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
1164 tegra_uart_read(tup, UART_IER);
1166 spin_unlock_irqrestore(&u->lock, flags);
1171 * Flush any TX data submitted for DMA and PIO. Called when the
1172 * TX circular buffer is reset.
1174 static void tegra_uart_flush_buffer(struct uart_port *u)
1176 struct tegra_uart_port *tup = to_tegra_uport(u);
1179 if (tup->tx_dma_chan)
1180 dmaengine_terminate_all(tup->tx_dma_chan);
1184 static const char *tegra_uart_type(struct uart_port *u)
1186 return TEGRA_UART_TYPE;
1189 static struct uart_ops tegra_uart_ops = {
1190 .tx_empty = tegra_uart_tx_empty,
1191 .set_mctrl = tegra_uart_set_mctrl,
1192 .get_mctrl = tegra_uart_get_mctrl,
1193 .stop_tx = tegra_uart_stop_tx,
1194 .start_tx = tegra_uart_start_tx,
1195 .stop_rx = tegra_uart_stop_rx,
1196 .flush_buffer = tegra_uart_flush_buffer,
1197 .enable_ms = tegra_uart_enable_ms,
1198 .break_ctl = tegra_uart_break_ctl,
1199 .startup = tegra_uart_startup,
1200 .shutdown = tegra_uart_shutdown,
1201 .set_termios = tegra_uart_set_termios,
1202 .type = tegra_uart_type,
1203 .request_port = tegra_uart_request_port,
1204 .release_port = tegra_uart_release_port,
1207 static struct uart_driver tegra_uart_driver = {
1208 .owner = THIS_MODULE,
1209 .driver_name = "tegra_hsuart",
1210 .dev_name = "ttyTHS",
1212 .nr = TEGRA_UART_MAXIMUM,
1215 static int tegra_uart_parse_dt(struct platform_device *pdev,
1216 struct tegra_uart_port *tup)
1218 struct device_node *np = pdev->dev.of_node;
1222 if (of_property_read_u32_array(np, "nvidia,dma-request-selector",
1224 tup->dma_req_sel = of_dma[1];
1226 dev_err(&pdev->dev, "missing dma requestor in device tree\n");
1230 port = of_alias_get_id(np, "serial");
1232 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port);
1235 tup->uport.line = port;
1237 tup->enable_modem_interrupt = of_property_read_bool(np,
1238 "nvidia,enable-modem-interrupt");
1242 struct tegra_uart_chip_data tegra20_uart_chip_data = {
1243 .tx_fifo_full_status = false,
1244 .allow_txfifo_reset_fifo_mode = true,
1245 .support_clk_src_div = false,
1248 struct tegra_uart_chip_data tegra30_uart_chip_data = {
1249 .tx_fifo_full_status = true,
1250 .allow_txfifo_reset_fifo_mode = false,
1251 .support_clk_src_div = true,
1254 static struct of_device_id tegra_uart_of_match[] = {
1256 .compatible = "nvidia,tegra30-hsuart",
1257 .data = &tegra30_uart_chip_data,
1259 .compatible = "nvidia,tegra20-hsuart",
1260 .data = &tegra20_uart_chip_data,
1264 MODULE_DEVICE_TABLE(of, tegra_uart_of_match);
1266 static int tegra_uart_probe(struct platform_device *pdev)
1268 struct tegra_uart_port *tup;
1269 struct uart_port *u;
1270 struct resource *resource;
1272 const struct tegra_uart_chip_data *cdata;
1273 const struct of_device_id *match;
1275 match = of_match_device(tegra_uart_of_match, &pdev->dev);
1277 dev_err(&pdev->dev, "Error: No device match found\n");
1280 cdata = match->data;
1282 tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL);
1284 dev_err(&pdev->dev, "Failed to allocate memory for tup\n");
1288 ret = tegra_uart_parse_dt(pdev, tup);
1293 u->dev = &pdev->dev;
1294 u->ops = &tegra_uart_ops;
1295 u->type = PORT_TEGRA;
1299 platform_set_drvdata(pdev, tup);
1300 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1302 dev_err(&pdev->dev, "No IO memory resource\n");
1306 u->mapbase = resource->start;
1307 u->membase = devm_ioremap_resource(&pdev->dev, resource);
1308 if (IS_ERR(u->membase))
1309 return PTR_ERR(u->membase);
1311 tup->uart_clk = devm_clk_get(&pdev->dev, NULL);
1312 if (IS_ERR(tup->uart_clk)) {
1313 dev_err(&pdev->dev, "Couldn't get the clock\n");
1314 return PTR_ERR(tup->uart_clk);
1317 u->iotype = UPIO_MEM32;
1318 u->irq = platform_get_irq(pdev, 0);
1320 ret = uart_add_one_port(&tegra_uart_driver, u);
1322 dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret);
1328 static int tegra_uart_remove(struct platform_device *pdev)
1330 struct tegra_uart_port *tup = platform_get_drvdata(pdev);
1331 struct uart_port *u = &tup->uport;
1333 uart_remove_one_port(&tegra_uart_driver, u);
1337 #ifdef CONFIG_PM_SLEEP
1338 static int tegra_uart_suspend(struct device *dev)
1340 struct tegra_uart_port *tup = dev_get_drvdata(dev);
1341 struct uart_port *u = &tup->uport;
1343 return uart_suspend_port(&tegra_uart_driver, u);
1346 static int tegra_uart_resume(struct device *dev)
1348 struct tegra_uart_port *tup = dev_get_drvdata(dev);
1349 struct uart_port *u = &tup->uport;
1351 return uart_resume_port(&tegra_uart_driver, u);
1355 static const struct dev_pm_ops tegra_uart_pm_ops = {
1356 SET_SYSTEM_SLEEP_PM_OPS(tegra_uart_suspend, tegra_uart_resume)
1359 static struct platform_driver tegra_uart_platform_driver = {
1360 .probe = tegra_uart_probe,
1361 .remove = tegra_uart_remove,
1363 .name = "serial-tegra",
1364 .of_match_table = tegra_uart_of_match,
1365 .pm = &tegra_uart_pm_ops,
1369 static int __init tegra_uart_init(void)
1373 ret = uart_register_driver(&tegra_uart_driver);
1375 pr_err("Could not register %s driver\n",
1376 tegra_uart_driver.driver_name);
1380 ret = platform_driver_register(&tegra_uart_platform_driver);
1382 pr_err("Uart platfrom driver register failed, e = %d\n", ret);
1383 uart_unregister_driver(&tegra_uart_driver);
1389 static void __exit tegra_uart_exit(void)
1391 pr_info("Unloading tegra uart driver\n");
1392 platform_driver_unregister(&tegra_uart_platform_driver);
1393 uart_unregister_driver(&tegra_uart_driver);
1396 module_init(tegra_uart_init);
1397 module_exit(tegra_uart_exit);
1399 MODULE_ALIAS("platform:serial-tegra");
1400 MODULE_DESCRIPTION("High speed UART driver for tegra chipset");
1401 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1402 MODULE_LICENSE("GPL v2");