1 // SPDX-License-Identifier: GPL-2.0
5 * High-speed serial driver for NVIDIA Tegra SoCs
7 * Copyright (c) 2012-2013, NVIDIA CORPORATION. All rights reserved.
9 * Author: Laxman Dewangan <ldewangan@nvidia.com>
12 #include <linux/clk.h>
13 #include <linux/debugfs.h>
14 #include <linux/delay.h>
15 #include <linux/dmaengine.h>
16 #include <linux/dma-mapping.h>
17 #include <linux/dmapool.h>
18 #include <linux/err.h>
20 #include <linux/irq.h>
21 #include <linux/module.h>
23 #include <linux/of_device.h>
24 #include <linux/pagemap.h>
25 #include <linux/platform_device.h>
26 #include <linux/reset.h>
27 #include <linux/serial.h>
28 #include <linux/serial_8250.h>
29 #include <linux/serial_core.h>
30 #include <linux/serial_reg.h>
31 #include <linux/slab.h>
32 #include <linux/string.h>
33 #include <linux/termios.h>
34 #include <linux/tty.h>
35 #include <linux/tty_flip.h>
37 #define TEGRA_UART_TYPE "TEGRA_UART"
38 #define TX_EMPTY_STATUS (UART_LSR_TEMT | UART_LSR_THRE)
39 #define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3)
41 #define TEGRA_UART_RX_DMA_BUFFER_SIZE 4096
42 #define TEGRA_UART_LSR_TXFIFO_FULL 0x100
43 #define TEGRA_UART_IER_EORD 0x20
44 #define TEGRA_UART_MCR_RTS_EN 0x40
45 #define TEGRA_UART_MCR_CTS_EN 0x20
46 #define TEGRA_UART_LSR_ANY (UART_LSR_OE | UART_LSR_BI | \
47 UART_LSR_PE | UART_LSR_FE)
48 #define TEGRA_UART_IRDA_CSR 0x08
49 #define TEGRA_UART_SIR_ENABLED 0x80
51 #define TEGRA_UART_TX_PIO 1
52 #define TEGRA_UART_TX_DMA 2
53 #define TEGRA_UART_MIN_DMA 16
54 #define TEGRA_UART_FIFO_SIZE 32
57 * Tx fifo trigger level setting in tegra uart is in
58 * reverse way then conventional uart.
60 #define TEGRA_UART_TX_TRIG_16B 0x00
61 #define TEGRA_UART_TX_TRIG_8B 0x10
62 #define TEGRA_UART_TX_TRIG_4B 0x20
63 #define TEGRA_UART_TX_TRIG_1B 0x30
65 #define TEGRA_UART_MAXIMUM 5
67 /* Default UART setting when started: 115200 no parity, stop, 8 data bits */
68 #define TEGRA_UART_DEFAULT_BAUD 115200
69 #define TEGRA_UART_DEFAULT_LSR UART_LCR_WLEN8
71 /* Tx transfer mode */
72 #define TEGRA_TX_PIO 1
73 #define TEGRA_TX_DMA 2
76 * tegra_uart_chip_data: SOC specific data.
78 * @tx_fifo_full_status: Status flag available for checking tx fifo full.
79 * @allow_txfifo_reset_fifo_mode: allow_tx fifo reset with fifo mode or not.
80 * Tegra30 does not allow this.
81 * @support_clk_src_div: Clock source support the clock divider.
83 struct tegra_uart_chip_data {
84 bool tx_fifo_full_status;
85 bool allow_txfifo_reset_fifo_mode;
86 bool support_clk_src_div;
89 struct tegra_uart_port {
90 struct uart_port uport;
91 const struct tegra_uart_chip_data *cdata;
94 struct reset_control *rst;
95 unsigned int current_baud;
98 unsigned long fcr_shadow;
99 unsigned long mcr_shadow;
100 unsigned long lcr_shadow;
101 unsigned long ier_shadow;
105 unsigned int tx_bytes;
107 bool enable_modem_interrupt;
113 struct dma_chan *rx_dma_chan;
114 struct dma_chan *tx_dma_chan;
115 dma_addr_t rx_dma_buf_phys;
116 dma_addr_t tx_dma_buf_phys;
117 unsigned char *rx_dma_buf_virt;
118 unsigned char *tx_dma_buf_virt;
119 struct dma_async_tx_descriptor *tx_dma_desc;
120 struct dma_async_tx_descriptor *rx_dma_desc;
121 dma_cookie_t tx_cookie;
122 dma_cookie_t rx_cookie;
123 unsigned int tx_bytes_requested;
124 unsigned int rx_bytes_requested;
127 static void tegra_uart_start_next_tx(struct tegra_uart_port *tup);
128 static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup);
130 static inline unsigned long tegra_uart_read(struct tegra_uart_port *tup,
133 return readl(tup->uport.membase + (reg << tup->uport.regshift));
136 static inline void tegra_uart_write(struct tegra_uart_port *tup, unsigned val,
139 writel(val, tup->uport.membase + (reg << tup->uport.regshift));
142 static inline struct tegra_uart_port *to_tegra_uport(struct uart_port *u)
144 return container_of(u, struct tegra_uart_port, uport);
147 static unsigned int tegra_uart_get_mctrl(struct uart_port *u)
149 struct tegra_uart_port *tup = to_tegra_uport(u);
152 * RI - Ring detector is active
153 * CD/DCD/CAR - Carrier detect is always active. For some reason
154 * linux has different names for carrier detect.
155 * DSR - Data Set ready is active as the hardware doesn't support it.
156 * Don't know if the linux support this yet?
157 * CTS - Clear to send. Always set to active, as the hardware handles
160 if (tup->enable_modem_interrupt)
161 return TIOCM_RI | TIOCM_CD | TIOCM_DSR | TIOCM_CTS;
165 static void set_rts(struct tegra_uart_port *tup, bool active)
169 mcr = tup->mcr_shadow;
171 mcr |= TEGRA_UART_MCR_RTS_EN;
173 mcr &= ~TEGRA_UART_MCR_RTS_EN;
174 if (mcr != tup->mcr_shadow) {
175 tegra_uart_write(tup, mcr, UART_MCR);
176 tup->mcr_shadow = mcr;
180 static void set_dtr(struct tegra_uart_port *tup, bool active)
184 mcr = tup->mcr_shadow;
188 mcr &= ~UART_MCR_DTR;
189 if (mcr != tup->mcr_shadow) {
190 tegra_uart_write(tup, mcr, UART_MCR);
191 tup->mcr_shadow = mcr;
195 static void tegra_uart_set_mctrl(struct uart_port *u, unsigned int mctrl)
197 struct tegra_uart_port *tup = to_tegra_uport(u);
200 tup->rts_active = !!(mctrl & TIOCM_RTS);
201 set_rts(tup, tup->rts_active);
203 dtr_enable = !!(mctrl & TIOCM_DTR);
204 set_dtr(tup, dtr_enable);
207 static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl)
209 struct tegra_uart_port *tup = to_tegra_uport(u);
212 lcr = tup->lcr_shadow;
216 lcr &= ~UART_LCR_SBC;
217 tegra_uart_write(tup, lcr, UART_LCR);
218 tup->lcr_shadow = lcr;
222 * tegra_uart_wait_cycle_time: Wait for N UART clock periods
224 * @tup: Tegra serial port data structure.
225 * @cycles: Number of clock periods to wait.
227 * Tegra UARTs are clocked at 16X the baud/bit rate and hence the UART
228 * clock speed is 16X the current baud rate.
230 static void tegra_uart_wait_cycle_time(struct tegra_uart_port *tup,
233 if (tup->current_baud)
234 udelay(DIV_ROUND_UP(cycles * 1000000, tup->current_baud * 16));
237 /* Wait for a symbol-time. */
238 static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup,
241 if (tup->current_baud)
242 udelay(DIV_ROUND_UP(syms * tup->symb_bit * 1000000,
246 static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
248 unsigned long fcr = tup->fcr_shadow;
250 if (tup->cdata->allow_txfifo_reset_fifo_mode) {
251 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
252 tegra_uart_write(tup, fcr, UART_FCR);
254 fcr &= ~UART_FCR_ENABLE_FIFO;
255 tegra_uart_write(tup, fcr, UART_FCR);
257 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
258 tegra_uart_write(tup, fcr, UART_FCR);
259 fcr |= UART_FCR_ENABLE_FIFO;
260 tegra_uart_write(tup, fcr, UART_FCR);
263 /* Dummy read to ensure the write is posted */
264 tegra_uart_read(tup, UART_SCR);
267 * For all tegra devices (up to t210), there is a hardware issue that
268 * requires software to wait for 32 UART clock periods for the flush
269 * to propagate, otherwise data could be lost.
271 tegra_uart_wait_cycle_time(tup, 32);
274 static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
277 unsigned int divisor;
281 if (tup->current_baud == baud)
284 if (tup->cdata->support_clk_src_div) {
286 ret = clk_set_rate(tup->uart_clk, rate);
288 dev_err(tup->uport.dev,
289 "clk_set_rate() failed for rate %lu\n", rate);
294 rate = clk_get_rate(tup->uart_clk);
295 divisor = DIV_ROUND_CLOSEST(rate, baud * 16);
298 lcr = tup->lcr_shadow;
299 lcr |= UART_LCR_DLAB;
300 tegra_uart_write(tup, lcr, UART_LCR);
302 tegra_uart_write(tup, divisor & 0xFF, UART_TX);
303 tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER);
305 lcr &= ~UART_LCR_DLAB;
306 tegra_uart_write(tup, lcr, UART_LCR);
308 /* Dummy read to ensure the write is posted */
309 tegra_uart_read(tup, UART_SCR);
311 tup->current_baud = baud;
313 /* wait two character intervals at new rate */
314 tegra_uart_wait_sym_time(tup, 2);
318 static char tegra_uart_decode_rx_error(struct tegra_uart_port *tup,
321 char flag = TTY_NORMAL;
323 if (unlikely(lsr & TEGRA_UART_LSR_ANY)) {
324 if (lsr & UART_LSR_OE) {
327 tup->uport.icount.overrun++;
328 dev_err(tup->uport.dev, "Got overrun errors\n");
329 } else if (lsr & UART_LSR_PE) {
332 tup->uport.icount.parity++;
333 dev_err(tup->uport.dev, "Got Parity errors\n");
334 } else if (lsr & UART_LSR_FE) {
336 tup->uport.icount.frame++;
337 dev_err(tup->uport.dev, "Got frame errors\n");
338 } else if (lsr & UART_LSR_BI) {
339 dev_err(tup->uport.dev, "Got Break\n");
340 tup->uport.icount.brk++;
341 /* If FIFO read error without any data, reset Rx FIFO */
342 if (!(lsr & UART_LSR_DR) && (lsr & UART_LSR_FIFOE))
343 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_RCVR);
349 static int tegra_uart_request_port(struct uart_port *u)
354 static void tegra_uart_release_port(struct uart_port *u)
356 /* Nothing to do here */
359 static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes)
361 struct circ_buf *xmit = &tup->uport.state->xmit;
364 for (i = 0; i < max_bytes; i++) {
365 BUG_ON(uart_circ_empty(xmit));
366 if (tup->cdata->tx_fifo_full_status) {
367 unsigned long lsr = tegra_uart_read(tup, UART_LSR);
368 if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL))
371 tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX);
372 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
373 tup->uport.icount.tx++;
377 static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup,
380 if (bytes > TEGRA_UART_MIN_DMA)
381 bytes = TEGRA_UART_MIN_DMA;
383 tup->tx_in_progress = TEGRA_UART_TX_PIO;
384 tup->tx_bytes = bytes;
385 tup->ier_shadow |= UART_IER_THRI;
386 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
389 static void tegra_uart_tx_dma_complete(void *args)
391 struct tegra_uart_port *tup = args;
392 struct circ_buf *xmit = &tup->uport.state->xmit;
393 struct dma_tx_state state;
397 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
398 count = tup->tx_bytes_requested - state.residue;
399 async_tx_ack(tup->tx_dma_desc);
400 spin_lock_irqsave(&tup->uport.lock, flags);
401 uart_xmit_advance(&tup->uport, count);
402 tup->tx_in_progress = 0;
403 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
404 uart_write_wakeup(&tup->uport);
405 tegra_uart_start_next_tx(tup);
406 spin_unlock_irqrestore(&tup->uport.lock, flags);
409 static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup,
412 struct circ_buf *xmit = &tup->uport.state->xmit;
413 dma_addr_t tx_phys_addr;
415 dma_sync_single_for_device(tup->uport.dev, tup->tx_dma_buf_phys,
416 UART_XMIT_SIZE, DMA_TO_DEVICE);
418 tup->tx_bytes = count & ~(0xF);
419 tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail;
420 tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan,
421 tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV,
423 if (!tup->tx_dma_desc) {
424 dev_err(tup->uport.dev, "Not able to get desc for Tx\n");
428 tup->tx_dma_desc->callback = tegra_uart_tx_dma_complete;
429 tup->tx_dma_desc->callback_param = tup;
430 tup->tx_in_progress = TEGRA_UART_TX_DMA;
431 tup->tx_bytes_requested = tup->tx_bytes;
432 tup->tx_cookie = dmaengine_submit(tup->tx_dma_desc);
433 dma_async_issue_pending(tup->tx_dma_chan);
437 static void tegra_uart_start_next_tx(struct tegra_uart_port *tup)
441 struct circ_buf *xmit = &tup->uport.state->xmit;
443 tail = (unsigned long)&xmit->buf[xmit->tail];
444 count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
448 if (count < TEGRA_UART_MIN_DMA)
449 tegra_uart_start_pio_tx(tup, count);
450 else if (BYTES_TO_ALIGN(tail) > 0)
451 tegra_uart_start_pio_tx(tup, BYTES_TO_ALIGN(tail));
453 tegra_uart_start_tx_dma(tup, count);
456 /* Called by serial core driver with u->lock taken. */
457 static void tegra_uart_start_tx(struct uart_port *u)
459 struct tegra_uart_port *tup = to_tegra_uport(u);
460 struct circ_buf *xmit = &u->state->xmit;
462 if (!uart_circ_empty(xmit) && !tup->tx_in_progress)
463 tegra_uart_start_next_tx(tup);
466 static unsigned int tegra_uart_tx_empty(struct uart_port *u)
468 struct tegra_uart_port *tup = to_tegra_uport(u);
469 unsigned int ret = 0;
472 spin_lock_irqsave(&u->lock, flags);
473 if (!tup->tx_in_progress) {
474 unsigned long lsr = tegra_uart_read(tup, UART_LSR);
475 if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS)
478 spin_unlock_irqrestore(&u->lock, flags);
482 static void tegra_uart_stop_tx(struct uart_port *u)
484 struct tegra_uart_port *tup = to_tegra_uport(u);
485 struct dma_tx_state state;
488 if (tup->tx_in_progress != TEGRA_UART_TX_DMA)
491 dmaengine_terminate_all(tup->tx_dma_chan);
492 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
493 count = tup->tx_bytes_requested - state.residue;
494 async_tx_ack(tup->tx_dma_desc);
495 uart_xmit_advance(&tup->uport, count);
496 tup->tx_in_progress = 0;
499 static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup)
501 struct circ_buf *xmit = &tup->uport.state->xmit;
503 tegra_uart_fill_tx_fifo(tup, tup->tx_bytes);
504 tup->tx_in_progress = 0;
505 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
506 uart_write_wakeup(&tup->uport);
507 tegra_uart_start_next_tx(tup);
510 static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup,
511 struct tty_port *tty)
514 char flag = TTY_NORMAL;
515 unsigned long lsr = 0;
518 lsr = tegra_uart_read(tup, UART_LSR);
519 if (!(lsr & UART_LSR_DR))
522 flag = tegra_uart_decode_rx_error(tup, lsr);
523 ch = (unsigned char) tegra_uart_read(tup, UART_RX);
524 tup->uport.icount.rx++;
526 if (!uart_handle_sysrq_char(&tup->uport, ch) && tty)
527 tty_insert_flip_char(tty, ch, flag);
531 static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup,
532 struct tty_port *tty,
537 /* If count is zero, then there is no data to be copied */
541 tup->uport.icount.rx += count;
543 dev_err(tup->uport.dev, "No tty port\n");
546 dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys,
547 TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
548 copied = tty_insert_flip_string(tty,
549 ((unsigned char *)(tup->rx_dma_buf_virt)), count);
550 if (copied != count) {
552 dev_err(tup->uport.dev, "RxData copy to tty layer failed\n");
554 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
555 TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
558 static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup,
559 unsigned int residue)
561 struct tty_port *port = &tup->uport.state->port;
562 struct tty_struct *tty = tty_port_tty_get(port);
565 async_tx_ack(tup->rx_dma_desc);
566 count = tup->rx_bytes_requested - residue;
568 /* If we are here, DMA is stopped */
569 tegra_uart_copy_rx_to_tty(tup, port, count);
571 tegra_uart_handle_rx_pio(tup, port);
573 tty_flip_buffer_push(port);
578 static void tegra_uart_rx_dma_complete(void *args)
580 struct tegra_uart_port *tup = args;
581 struct uart_port *u = &tup->uport;
583 struct dma_tx_state state;
584 enum dma_status status;
586 spin_lock_irqsave(&u->lock, flags);
588 status = dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
590 if (status == DMA_IN_PROGRESS) {
591 dev_dbg(tup->uport.dev, "RX DMA is in progress\n");
595 /* Deactivate flow control to stop sender */
599 tegra_uart_rx_buffer_push(tup, 0);
600 tegra_uart_start_rx_dma(tup);
602 /* Activate flow control to start transfer */
607 spin_unlock_irqrestore(&u->lock, flags);
610 static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
612 struct dma_tx_state state;
614 /* Deactivate flow control to stop sender */
618 dmaengine_terminate_all(tup->rx_dma_chan);
619 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
620 tegra_uart_rx_buffer_push(tup, state.residue);
621 tegra_uart_start_rx_dma(tup);
627 static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup)
629 unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE;
631 tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan,
632 tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM,
634 if (!tup->rx_dma_desc) {
635 dev_err(tup->uport.dev, "Not able to get desc for Rx\n");
639 tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete;
640 tup->rx_dma_desc->callback_param = tup;
641 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
642 count, DMA_TO_DEVICE);
643 tup->rx_bytes_requested = count;
644 tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc);
645 dma_async_issue_pending(tup->rx_dma_chan);
649 static void tegra_uart_handle_modem_signal_change(struct uart_port *u)
651 struct tegra_uart_port *tup = to_tegra_uport(u);
654 msr = tegra_uart_read(tup, UART_MSR);
655 if (!(msr & UART_MSR_ANY_DELTA))
658 if (msr & UART_MSR_TERI)
659 tup->uport.icount.rng++;
660 if (msr & UART_MSR_DDSR)
661 tup->uport.icount.dsr++;
662 /* We may only get DDCD when HW init and reset */
663 if (msr & UART_MSR_DDCD)
664 uart_handle_dcd_change(&tup->uport, msr & UART_MSR_DCD);
665 /* Will start/stop_tx accordingly */
666 if (msr & UART_MSR_DCTS)
667 uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS);
670 static irqreturn_t tegra_uart_isr(int irq, void *data)
672 struct tegra_uart_port *tup = data;
673 struct uart_port *u = &tup->uport;
676 bool is_rx_int = false;
679 spin_lock_irqsave(&u->lock, flags);
681 iir = tegra_uart_read(tup, UART_IIR);
682 if (iir & UART_IIR_NO_INT) {
684 tegra_uart_handle_rx_dma(tup);
685 if (tup->rx_in_progress) {
686 ier = tup->ier_shadow;
687 ier |= (UART_IER_RLSI | UART_IER_RTOIE |
688 TEGRA_UART_IER_EORD);
689 tup->ier_shadow = ier;
690 tegra_uart_write(tup, ier, UART_IER);
693 spin_unlock_irqrestore(&u->lock, flags);
697 switch ((iir >> 1) & 0x7) {
698 case 0: /* Modem signal change interrupt */
699 tegra_uart_handle_modem_signal_change(u);
702 case 1: /* Transmit interrupt only triggered when using PIO */
703 tup->ier_shadow &= ~UART_IER_THRI;
704 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
705 tegra_uart_handle_tx_pio(tup);
708 case 4: /* End of data */
709 case 6: /* Rx timeout */
710 case 2: /* Receive */
713 /* Disable Rx interrupts */
714 ier = tup->ier_shadow;
716 tegra_uart_write(tup, ier, UART_IER);
717 ier &= ~(UART_IER_RDI | UART_IER_RLSI |
718 UART_IER_RTOIE | TEGRA_UART_IER_EORD);
719 tup->ier_shadow = ier;
720 tegra_uart_write(tup, ier, UART_IER);
724 case 3: /* Receive error */
725 tegra_uart_decode_rx_error(tup,
726 tegra_uart_read(tup, UART_LSR));
729 case 5: /* break nothing to handle */
730 case 7: /* break nothing to handle */
736 static void tegra_uart_stop_rx(struct uart_port *u)
738 struct tegra_uart_port *tup = to_tegra_uport(u);
739 struct dma_tx_state state;
745 if (!tup->rx_in_progress)
748 tegra_uart_wait_sym_time(tup, 1); /* wait a character interval */
750 ier = tup->ier_shadow;
751 ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
752 TEGRA_UART_IER_EORD);
753 tup->ier_shadow = ier;
754 tegra_uart_write(tup, ier, UART_IER);
755 tup->rx_in_progress = 0;
756 dmaengine_terminate_all(tup->rx_dma_chan);
757 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
758 tegra_uart_rx_buffer_push(tup, state.residue);
761 static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
764 unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud);
765 unsigned long fifo_empty_time = tup->uport.fifosize * char_time;
766 unsigned long wait_time;
771 /* Disable interrupts */
772 tegra_uart_write(tup, 0, UART_IER);
774 lsr = tegra_uart_read(tup, UART_LSR);
775 if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
776 msr = tegra_uart_read(tup, UART_MSR);
777 mcr = tegra_uart_read(tup, UART_MCR);
778 if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS))
779 dev_err(tup->uport.dev,
780 "Tx Fifo not empty, CTS disabled, waiting\n");
782 /* Wait for Tx fifo to be empty */
783 while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
784 wait_time = min(fifo_empty_time, 100lu);
786 fifo_empty_time -= wait_time;
787 if (!fifo_empty_time) {
788 msr = tegra_uart_read(tup, UART_MSR);
789 mcr = tegra_uart_read(tup, UART_MCR);
790 if ((mcr & TEGRA_UART_MCR_CTS_EN) &&
791 (msr & UART_MSR_CTS))
792 dev_err(tup->uport.dev,
793 "Slave not ready\n");
796 lsr = tegra_uart_read(tup, UART_LSR);
800 spin_lock_irqsave(&tup->uport.lock, flags);
801 /* Reset the Rx and Tx FIFOs */
802 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
803 tup->current_baud = 0;
804 spin_unlock_irqrestore(&tup->uport.lock, flags);
806 clk_disable_unprepare(tup->uart_clk);
809 static int tegra_uart_hw_init(struct tegra_uart_port *tup)
817 tup->current_baud = 0;
819 clk_prepare_enable(tup->uart_clk);
821 /* Reset the UART controller to clear all previous status.*/
822 reset_control_assert(tup->rst);
824 reset_control_deassert(tup->rst);
826 tup->rx_in_progress = 0;
827 tup->tx_in_progress = 0;
830 * Set the trigger level
834 * For receive, this will interrupt the CPU after that many number of
835 * bytes are received, for the remaining bytes the receive timeout
836 * interrupt is received. Rx high watermark is set to 4.
838 * For transmit, if the trasnmit interrupt is enabled, this will
839 * interrupt the CPU when the number of entries in the FIFO reaches the
840 * low watermark. Tx low watermark is set to 16 bytes.
844 * Set the Tx trigger to 16. This should match the DMA burst size that
845 * programmed in the DMA registers.
847 tup->fcr_shadow = UART_FCR_ENABLE_FIFO;
848 tup->fcr_shadow |= UART_FCR_R_TRIG_01;
849 tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B;
850 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
852 /* Dummy read to ensure the write is posted */
853 tegra_uart_read(tup, UART_SCR);
856 * For all tegra devices (up to t210), there is a hardware issue that
857 * requires software to wait for 3 UART clock periods after enabling
858 * the TX fifo, otherwise data could be lost.
860 tegra_uart_wait_cycle_time(tup, 3);
863 * Initialize the UART with default configuration
864 * (115200, N, 8, 1) so that the receive DMA buffer may be
867 tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR;
868 tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD);
869 tup->fcr_shadow |= UART_FCR_DMA_SELECT;
870 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
872 ret = tegra_uart_start_rx_dma(tup);
874 dev_err(tup->uport.dev, "Not able to start Rx DMA\n");
877 tup->rx_in_progress = 1;
880 * Enable IE_RXS for the receive status interrupts like line errros.
881 * Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd.
883 * If using DMA mode, enable EORD instead of receive interrupt which
884 * will interrupt after the UART is done with the receive instead of
885 * the interrupt when the FIFO "threshold" is reached.
887 * EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when
888 * the DATA is sitting in the FIFO and couldn't be transferred to the
889 * DMA as the DMA size alignment(4 bytes) is not met. EORD will be
890 * triggered when there is a pause of the incomming data stream for 4
893 * For pauses in the data which is not aligned to 4 bytes, we get
894 * both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first
897 tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | TEGRA_UART_IER_EORD;
898 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
902 static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
906 dmaengine_terminate_all(tup->rx_dma_chan);
907 dma_release_channel(tup->rx_dma_chan);
908 dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,
909 tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);
910 tup->rx_dma_chan = NULL;
911 tup->rx_dma_buf_phys = 0;
912 tup->rx_dma_buf_virt = NULL;
914 dmaengine_terminate_all(tup->tx_dma_chan);
915 dma_release_channel(tup->tx_dma_chan);
916 dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,
917 UART_XMIT_SIZE, DMA_TO_DEVICE);
918 tup->tx_dma_chan = NULL;
919 tup->tx_dma_buf_phys = 0;
920 tup->tx_dma_buf_virt = NULL;
924 static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
927 struct dma_chan *dma_chan;
928 unsigned char *dma_buf;
931 struct dma_slave_config dma_sconfig;
933 dma_chan = dma_request_slave_channel_reason(tup->uport.dev,
934 dma_to_memory ? "rx" : "tx");
935 if (IS_ERR(dma_chan)) {
936 ret = PTR_ERR(dma_chan);
937 dev_err(tup->uport.dev,
938 "DMA channel alloc failed: %d\n", ret);
943 dma_buf = dma_alloc_coherent(tup->uport.dev,
944 TEGRA_UART_RX_DMA_BUFFER_SIZE,
945 &dma_phys, GFP_KERNEL);
947 dev_err(tup->uport.dev,
948 "Not able to allocate the dma buffer\n");
949 dma_release_channel(dma_chan);
952 dma_sconfig.src_addr = tup->uport.mapbase;
953 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
954 dma_sconfig.src_maxburst = 4;
955 tup->rx_dma_chan = dma_chan;
956 tup->rx_dma_buf_virt = dma_buf;
957 tup->rx_dma_buf_phys = dma_phys;
959 dma_phys = dma_map_single(tup->uport.dev,
960 tup->uport.state->xmit.buf, UART_XMIT_SIZE,
962 if (dma_mapping_error(tup->uport.dev, dma_phys)) {
963 dev_err(tup->uport.dev, "dma_map_single tx failed\n");
964 dma_release_channel(dma_chan);
967 dma_buf = tup->uport.state->xmit.buf;
968 dma_sconfig.dst_addr = tup->uport.mapbase;
969 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
970 dma_sconfig.dst_maxburst = 16;
971 tup->tx_dma_chan = dma_chan;
972 tup->tx_dma_buf_virt = dma_buf;
973 tup->tx_dma_buf_phys = dma_phys;
976 ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
978 dev_err(tup->uport.dev,
979 "Dma slave config failed, err = %d\n", ret);
980 tegra_uart_dma_channel_free(tup, dma_to_memory);
987 static int tegra_uart_startup(struct uart_port *u)
989 struct tegra_uart_port *tup = to_tegra_uport(u);
992 ret = tegra_uart_dma_channel_allocate(tup, false);
994 dev_err(u->dev, "Tx Dma allocation failed, err = %d\n", ret);
998 ret = tegra_uart_dma_channel_allocate(tup, true);
1000 dev_err(u->dev, "Rx Dma allocation failed, err = %d\n", ret);
1004 ret = tegra_uart_hw_init(tup);
1006 dev_err(u->dev, "Uart HW init failed, err = %d\n", ret);
1010 ret = request_irq(u->irq, tegra_uart_isr, 0,
1011 dev_name(u->dev), tup);
1013 dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq);
1019 tegra_uart_dma_channel_free(tup, true);
1021 tegra_uart_dma_channel_free(tup, false);
1026 * Flush any TX data submitted for DMA and PIO. Called when the
1027 * TX circular buffer is reset.
1029 static void tegra_uart_flush_buffer(struct uart_port *u)
1031 struct tegra_uart_port *tup = to_tegra_uport(u);
1034 if (tup->tx_dma_chan)
1035 dmaengine_terminate_all(tup->tx_dma_chan);
1038 static void tegra_uart_shutdown(struct uart_port *u)
1040 struct tegra_uart_port *tup = to_tegra_uport(u);
1042 tegra_uart_hw_deinit(tup);
1044 tup->rx_in_progress = 0;
1045 tup->tx_in_progress = 0;
1047 tegra_uart_dma_channel_free(tup, true);
1048 tegra_uart_dma_channel_free(tup, false);
1049 free_irq(u->irq, tup);
1052 static void tegra_uart_enable_ms(struct uart_port *u)
1054 struct tegra_uart_port *tup = to_tegra_uport(u);
1056 if (tup->enable_modem_interrupt) {
1057 tup->ier_shadow |= UART_IER_MSI;
1058 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
1062 static void tegra_uart_set_termios(struct uart_port *u,
1063 struct ktermios *termios, struct ktermios *oldtermios)
1065 struct tegra_uart_port *tup = to_tegra_uport(u);
1067 unsigned long flags;
1070 struct clk *parent_clk = clk_get_parent(tup->uart_clk);
1071 unsigned long parent_clk_rate = clk_get_rate(parent_clk);
1072 int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF;
1075 spin_lock_irqsave(&u->lock, flags);
1077 /* Changing configuration, it is safe to stop any rx now */
1078 if (tup->rts_active)
1079 set_rts(tup, false);
1081 /* Clear all interrupts as configuration is going to be change */
1082 tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER);
1083 tegra_uart_read(tup, UART_IER);
1084 tegra_uart_write(tup, 0, UART_IER);
1085 tegra_uart_read(tup, UART_IER);
1088 lcr = tup->lcr_shadow;
1089 lcr &= ~UART_LCR_PARITY;
1091 /* CMSPAR isn't supported by this driver */
1092 termios->c_cflag &= ~CMSPAR;
1094 if ((termios->c_cflag & PARENB) == PARENB) {
1096 if (termios->c_cflag & PARODD) {
1097 lcr |= UART_LCR_PARITY;
1098 lcr &= ~UART_LCR_EPAR;
1099 lcr &= ~UART_LCR_SPAR;
1101 lcr |= UART_LCR_PARITY;
1102 lcr |= UART_LCR_EPAR;
1103 lcr &= ~UART_LCR_SPAR;
1107 lcr &= ~UART_LCR_WLEN8;
1108 switch (termios->c_cflag & CSIZE) {
1110 lcr |= UART_LCR_WLEN5;
1114 lcr |= UART_LCR_WLEN6;
1118 lcr |= UART_LCR_WLEN7;
1122 lcr |= UART_LCR_WLEN8;
1128 if (termios->c_cflag & CSTOPB) {
1129 lcr |= UART_LCR_STOP;
1132 lcr &= ~UART_LCR_STOP;
1136 tegra_uart_write(tup, lcr, UART_LCR);
1137 tup->lcr_shadow = lcr;
1138 tup->symb_bit = symb_bit;
1141 baud = uart_get_baud_rate(u, termios, oldtermios,
1142 parent_clk_rate/max_divider,
1143 parent_clk_rate/16);
1144 spin_unlock_irqrestore(&u->lock, flags);
1145 tegra_set_baudrate(tup, baud);
1146 if (tty_termios_baud_rate(termios))
1147 tty_termios_encode_baud_rate(termios, baud, baud);
1148 spin_lock_irqsave(&u->lock, flags);
1151 if (termios->c_cflag & CRTSCTS) {
1152 tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN;
1153 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
1154 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
1155 /* if top layer has asked to set rts active then do so here */
1156 if (tup->rts_active)
1159 tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN;
1160 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
1161 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
1164 /* update the port timeout based on new settings */
1165 uart_update_timeout(u, termios->c_cflag, baud);
1167 /* Make sure all write has completed */
1168 tegra_uart_read(tup, UART_IER);
1170 /* Reenable interrupt */
1171 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
1172 tegra_uart_read(tup, UART_IER);
1174 spin_unlock_irqrestore(&u->lock, flags);
1177 static const char *tegra_uart_type(struct uart_port *u)
1179 return TEGRA_UART_TYPE;
1182 static const struct uart_ops tegra_uart_ops = {
1183 .tx_empty = tegra_uart_tx_empty,
1184 .set_mctrl = tegra_uart_set_mctrl,
1185 .get_mctrl = tegra_uart_get_mctrl,
1186 .stop_tx = tegra_uart_stop_tx,
1187 .start_tx = tegra_uart_start_tx,
1188 .stop_rx = tegra_uart_stop_rx,
1189 .flush_buffer = tegra_uart_flush_buffer,
1190 .enable_ms = tegra_uart_enable_ms,
1191 .break_ctl = tegra_uart_break_ctl,
1192 .startup = tegra_uart_startup,
1193 .shutdown = tegra_uart_shutdown,
1194 .set_termios = tegra_uart_set_termios,
1195 .type = tegra_uart_type,
1196 .request_port = tegra_uart_request_port,
1197 .release_port = tegra_uart_release_port,
1200 static struct uart_driver tegra_uart_driver = {
1201 .owner = THIS_MODULE,
1202 .driver_name = "tegra_hsuart",
1203 .dev_name = "ttyTHS",
1205 .nr = TEGRA_UART_MAXIMUM,
1208 static int tegra_uart_parse_dt(struct platform_device *pdev,
1209 struct tegra_uart_port *tup)
1211 struct device_node *np = pdev->dev.of_node;
1214 port = of_alias_get_id(np, "serial");
1216 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port);
1219 tup->uport.line = port;
1221 tup->enable_modem_interrupt = of_property_read_bool(np,
1222 "nvidia,enable-modem-interrupt");
1226 static struct tegra_uart_chip_data tegra20_uart_chip_data = {
1227 .tx_fifo_full_status = false,
1228 .allow_txfifo_reset_fifo_mode = true,
1229 .support_clk_src_div = false,
1232 static struct tegra_uart_chip_data tegra30_uart_chip_data = {
1233 .tx_fifo_full_status = true,
1234 .allow_txfifo_reset_fifo_mode = false,
1235 .support_clk_src_div = true,
1238 static const struct of_device_id tegra_uart_of_match[] = {
1240 .compatible = "nvidia,tegra30-hsuart",
1241 .data = &tegra30_uart_chip_data,
1243 .compatible = "nvidia,tegra20-hsuart",
1244 .data = &tegra20_uart_chip_data,
1248 MODULE_DEVICE_TABLE(of, tegra_uart_of_match);
1250 static int tegra_uart_probe(struct platform_device *pdev)
1252 struct tegra_uart_port *tup;
1253 struct uart_port *u;
1254 struct resource *resource;
1256 const struct tegra_uart_chip_data *cdata;
1257 const struct of_device_id *match;
1259 match = of_match_device(tegra_uart_of_match, &pdev->dev);
1261 dev_err(&pdev->dev, "Error: No device match found\n");
1264 cdata = match->data;
1266 tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL);
1268 dev_err(&pdev->dev, "Failed to allocate memory for tup\n");
1272 ret = tegra_uart_parse_dt(pdev, tup);
1277 u->dev = &pdev->dev;
1278 u->ops = &tegra_uart_ops;
1279 u->type = PORT_TEGRA;
1283 platform_set_drvdata(pdev, tup);
1284 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1286 dev_err(&pdev->dev, "No IO memory resource\n");
1290 u->mapbase = resource->start;
1291 u->membase = devm_ioremap_resource(&pdev->dev, resource);
1292 if (IS_ERR(u->membase))
1293 return PTR_ERR(u->membase);
1295 tup->uart_clk = devm_clk_get(&pdev->dev, NULL);
1296 if (IS_ERR(tup->uart_clk)) {
1297 dev_err(&pdev->dev, "Couldn't get the clock\n");
1298 return PTR_ERR(tup->uart_clk);
1301 tup->rst = devm_reset_control_get_exclusive(&pdev->dev, "serial");
1302 if (IS_ERR(tup->rst)) {
1303 dev_err(&pdev->dev, "Couldn't get the reset\n");
1304 return PTR_ERR(tup->rst);
1307 u->iotype = UPIO_MEM32;
1308 ret = platform_get_irq(pdev, 0);
1310 dev_err(&pdev->dev, "Couldn't get IRQ\n");
1315 ret = uart_add_one_port(&tegra_uart_driver, u);
1317 dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret);
1323 static int tegra_uart_remove(struct platform_device *pdev)
1325 struct tegra_uart_port *tup = platform_get_drvdata(pdev);
1326 struct uart_port *u = &tup->uport;
1328 uart_remove_one_port(&tegra_uart_driver, u);
1332 #ifdef CONFIG_PM_SLEEP
1333 static int tegra_uart_suspend(struct device *dev)
1335 struct tegra_uart_port *tup = dev_get_drvdata(dev);
1336 struct uart_port *u = &tup->uport;
1338 return uart_suspend_port(&tegra_uart_driver, u);
1341 static int tegra_uart_resume(struct device *dev)
1343 struct tegra_uart_port *tup = dev_get_drvdata(dev);
1344 struct uart_port *u = &tup->uport;
1346 return uart_resume_port(&tegra_uart_driver, u);
1350 static const struct dev_pm_ops tegra_uart_pm_ops = {
1351 SET_SYSTEM_SLEEP_PM_OPS(tegra_uart_suspend, tegra_uart_resume)
1354 static struct platform_driver tegra_uart_platform_driver = {
1355 .probe = tegra_uart_probe,
1356 .remove = tegra_uart_remove,
1358 .name = "serial-tegra",
1359 .of_match_table = tegra_uart_of_match,
1360 .pm = &tegra_uart_pm_ops,
1364 static int __init tegra_uart_init(void)
1368 ret = uart_register_driver(&tegra_uart_driver);
1370 pr_err("Could not register %s driver\n",
1371 tegra_uart_driver.driver_name);
1375 ret = platform_driver_register(&tegra_uart_platform_driver);
1377 pr_err("Uart platform driver register failed, e = %d\n", ret);
1378 uart_unregister_driver(&tegra_uart_driver);
1384 static void __exit tegra_uart_exit(void)
1386 pr_info("Unloading tegra uart driver\n");
1387 platform_driver_unregister(&tegra_uart_platform_driver);
1388 uart_unregister_driver(&tegra_uart_driver);
1391 module_init(tegra_uart_init);
1392 module_exit(tegra_uart_exit);
1394 MODULE_ALIAS("platform:serial-tegra");
1395 MODULE_DESCRIPTION("High speed UART driver for tegra chipset");
1396 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1397 MODULE_LICENSE("GPL v2");