2 * Driver for AMBA serial ports
4 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
6 * Copyright 1999 ARM Limited
7 * Copyright (C) 2000 Deep Blue Solutions Ltd.
8 * Copyright (C) 2010 ST-Ericsson SA
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 * This is a generic driver for ARM AMBA-type serial ports. They
25 * have a lot of 16550-like features, but are not register compatible.
26 * Note that although they do have CTS, DCD and DSR inputs, they do
27 * not have an RI input, nor do they have DTR or RTS outputs. If
28 * required, these have to be supplied via some other means (eg, GPIO)
29 * and hooked into this driver.
32 #if defined(CONFIG_SERIAL_AMBA_PL011_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
36 #include <linux/module.h>
37 #include <linux/ioport.h>
38 #include <linux/init.h>
39 #include <linux/console.h>
40 #include <linux/sysrq.h>
41 #include <linux/device.h>
42 #include <linux/tty.h>
43 #include <linux/tty_flip.h>
44 #include <linux/serial_core.h>
45 #include <linux/serial.h>
46 #include <linux/amba/bus.h>
47 #include <linux/amba/serial.h>
48 #include <linux/clk.h>
49 #include <linux/slab.h>
50 #include <linux/dmaengine.h>
51 #include <linux/dma-mapping.h>
52 #include <linux/scatterlist.h>
53 #include <linux/delay.h>
54 #include <linux/types.h>
57 #include <asm/sizes.h>
61 #define SERIAL_AMBA_MAJOR 204
62 #define SERIAL_AMBA_MINOR 64
63 #define SERIAL_AMBA_NR UART_NR
65 #define AMBA_ISR_PASS_LIMIT 256
67 #define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE)
68 #define UART_DUMMY_DR_RX (1 << 16)
71 #define UART_WA_SAVE_NR 14
73 static void pl011_lockup_wa(unsigned long data);
74 static const u32 uart_wa_reg[UART_WA_SAVE_NR] = {
91 static u32 uart_wa_regdata[UART_WA_SAVE_NR];
92 static DECLARE_TASKLET(pl011_lockup_tlet, pl011_lockup_wa, 0);
94 /* There is by now at least one vendor with differing details, so handle it */
97 unsigned int fifosize;
101 bool interrupt_may_hang; /* vendor-specific */
105 static struct vendor_data vendor_arm = {
106 .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
108 .lcrh_tx = UART011_LCRH,
109 .lcrh_rx = UART011_LCRH,
110 .oversampling = false,
111 .dma_threshold = false,
114 static struct vendor_data vendor_st = {
115 .ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF,
117 .lcrh_tx = ST_UART011_LCRH_TX,
118 .lcrh_rx = ST_UART011_LCRH_RX,
119 .oversampling = true,
120 .interrupt_may_hang = true,
121 .dma_threshold = true,
124 static struct uart_amba_port *amba_ports[UART_NR];
126 /* Deals with DMA transactions */
129 struct scatterlist sg;
133 struct pl011_dmarx_data {
134 struct dma_chan *chan;
135 struct completion complete;
137 struct pl011_sgbuf sgbuf_a;
138 struct pl011_sgbuf sgbuf_b;
143 struct pl011_dmatx_data {
144 struct dma_chan *chan;
145 struct scatterlist sg;
151 * We wrap our port structure around the generic uart_port.
153 struct uart_amba_port {
154 struct uart_port port;
156 const struct vendor_data *vendor;
157 unsigned int dmacr; /* dma control reg */
158 unsigned int im; /* interrupt mask */
159 unsigned int old_status;
160 unsigned int fifosize; /* vendor-specific */
161 unsigned int lcrh_tx; /* vendor-specific */
162 unsigned int lcrh_rx; /* vendor-specific */
165 bool interrupt_may_hang; /* vendor-specific */
166 #ifdef CONFIG_DMA_ENGINE
170 struct pl011_dmarx_data dmarx;
171 struct pl011_dmatx_data dmatx;
176 * Reads up to 256 characters from the FIFO or until it's empty and
177 * inserts them into the TTY layer. Returns the number of characters
178 * read from the FIFO.
180 static int pl011_fifo_to_tty(struct uart_amba_port *uap)
183 unsigned int flag, max_count = 256;
186 while (max_count--) {
187 status = readw(uap->port.membase + UART01x_FR);
188 if (status & UART01x_FR_RXFE)
191 /* Take chars from the FIFO and update status */
192 ch = readw(uap->port.membase + UART01x_DR) |
195 uap->port.icount.rx++;
198 if (unlikely(ch & UART_DR_ERROR)) {
199 if (ch & UART011_DR_BE) {
200 ch &= ~(UART011_DR_FE | UART011_DR_PE);
201 uap->port.icount.brk++;
202 if (uart_handle_break(&uap->port))
204 } else if (ch & UART011_DR_PE)
205 uap->port.icount.parity++;
206 else if (ch & UART011_DR_FE)
207 uap->port.icount.frame++;
208 if (ch & UART011_DR_OE)
209 uap->port.icount.overrun++;
211 ch &= uap->port.read_status_mask;
213 if (ch & UART011_DR_BE)
215 else if (ch & UART011_DR_PE)
217 else if (ch & UART011_DR_FE)
221 if (uart_handle_sysrq_char(&uap->port, ch & 255))
224 uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
232 * All the DMA operation mode stuff goes inside this ifdef.
233 * This assumes that you have a generic DMA device interface,
234 * no custom DMA interfaces are supported.
236 #ifdef CONFIG_DMA_ENGINE
238 #define PL011_DMA_BUFFER_SIZE PAGE_SIZE
240 static int pl011_sgbuf_init(struct dma_chan *chan, struct pl011_sgbuf *sg,
241 enum dma_data_direction dir)
243 sg->buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL);
247 sg_init_one(&sg->sg, sg->buf, PL011_DMA_BUFFER_SIZE);
249 if (dma_map_sg(chan->device->dev, &sg->sg, 1, dir) != 1) {
256 static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg,
257 enum dma_data_direction dir)
260 dma_unmap_sg(chan->device->dev, &sg->sg, 1, dir);
265 static void pl011_dma_probe_initcall(struct uart_amba_port *uap)
267 /* DMA is the sole user of the platform data right now */
268 struct amba_pl011_data *plat = uap->port.dev->platform_data;
269 struct dma_slave_config tx_conf = {
270 .dst_addr = uap->port.mapbase + UART01x_DR,
271 .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
272 .direction = DMA_MEM_TO_DEV,
273 .dst_maxburst = uap->fifosize >> 1,
276 struct dma_chan *chan;
279 /* We need platform data */
280 if (!plat || !plat->dma_filter) {
281 dev_info(uap->port.dev, "no DMA platform data\n");
285 /* Try to acquire a generic DMA engine slave TX channel */
287 dma_cap_set(DMA_SLAVE, mask);
289 chan = dma_request_channel(mask, plat->dma_filter, plat->dma_tx_param);
291 dev_err(uap->port.dev, "no TX DMA channel!\n");
295 dmaengine_slave_config(chan, &tx_conf);
296 uap->dmatx.chan = chan;
298 dev_info(uap->port.dev, "DMA channel TX %s\n",
299 dma_chan_name(uap->dmatx.chan));
301 /* Optionally make use of an RX channel as well */
302 if (plat->dma_rx_param) {
303 struct dma_slave_config rx_conf = {
304 .src_addr = uap->port.mapbase + UART01x_DR,
305 .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
306 .direction = DMA_DEV_TO_MEM,
307 .src_maxburst = uap->fifosize >> 1,
311 chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param);
313 dev_err(uap->port.dev, "no RX DMA channel!\n");
317 dmaengine_slave_config(chan, &rx_conf);
318 uap->dmarx.chan = chan;
320 dev_info(uap->port.dev, "DMA channel RX %s\n",
321 dma_chan_name(uap->dmarx.chan));
327 * Stack up the UARTs and let the above initcall be done at device
328 * initcall time, because the serial driver is called as an arch
329 * initcall, and at this time the DMA subsystem is not yet registered.
330 * At this point the driver will switch over to using DMA where desired.
333 struct list_head node;
334 struct uart_amba_port *uap;
337 static LIST_HEAD(pl011_dma_uarts);
339 static int __init pl011_dma_initcall(void)
341 struct list_head *node, *tmp;
343 list_for_each_safe(node, tmp, &pl011_dma_uarts) {
344 struct dma_uap *dmau = list_entry(node, struct dma_uap, node);
345 pl011_dma_probe_initcall(dmau->uap);
352 device_initcall(pl011_dma_initcall);
354 static void pl011_dma_probe(struct uart_amba_port *uap)
356 struct dma_uap *dmau = kzalloc(sizeof(struct dma_uap), GFP_KERNEL);
359 list_add_tail(&dmau->node, &pl011_dma_uarts);
363 static void pl011_dma_probe(struct uart_amba_port *uap)
365 pl011_dma_probe_initcall(uap);
369 static void pl011_dma_remove(struct uart_amba_port *uap)
371 /* TODO: remove the initcall if it has not yet executed */
373 dma_release_channel(uap->dmatx.chan);
375 dma_release_channel(uap->dmarx.chan);
378 /* Forward declare this for the refill routine */
379 static int pl011_dma_tx_refill(struct uart_amba_port *uap);
382 * The current DMA TX buffer has been sent.
383 * Try to queue up another DMA buffer.
385 static void pl011_dma_tx_callback(void *data)
387 struct uart_amba_port *uap = data;
388 struct pl011_dmatx_data *dmatx = &uap->dmatx;
392 spin_lock_irqsave(&uap->port.lock, flags);
393 if (uap->dmatx.queued)
394 dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1,
398 uap->dmacr = dmacr & ~UART011_TXDMAE;
399 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
402 * If TX DMA was disabled, it means that we've stopped the DMA for
403 * some reason (eg, XOFF received, or we want to send an X-char.)
405 * Note: we need to be careful here of a potential race between DMA
406 * and the rest of the driver - if the driver disables TX DMA while
407 * a TX buffer completing, we must update the tx queued status to
408 * get further refills (hence we check dmacr).
410 if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) ||
411 uart_circ_empty(&uap->port.state->xmit)) {
412 uap->dmatx.queued = false;
413 spin_unlock_irqrestore(&uap->port.lock, flags);
417 if (pl011_dma_tx_refill(uap) <= 0) {
419 * We didn't queue a DMA buffer for some reason, but we
420 * have data pending to be sent. Re-enable the TX IRQ.
422 uap->im |= UART011_TXIM;
423 writew(uap->im, uap->port.membase + UART011_IMSC);
425 spin_unlock_irqrestore(&uap->port.lock, flags);
429 * Try to refill the TX DMA buffer.
430 * Locking: called with port lock held and IRQs disabled.
432 * 1 if we queued up a TX DMA buffer.
433 * 0 if we didn't want to handle this by DMA
436 static int pl011_dma_tx_refill(struct uart_amba_port *uap)
438 struct pl011_dmatx_data *dmatx = &uap->dmatx;
439 struct dma_chan *chan = dmatx->chan;
440 struct dma_device *dma_dev = chan->device;
441 struct dma_async_tx_descriptor *desc;
442 struct circ_buf *xmit = &uap->port.state->xmit;
446 * Try to avoid the overhead involved in using DMA if the
447 * transaction fits in the first half of the FIFO, by using
448 * the standard interrupt handling. This ensures that we
449 * issue a uart_write_wakeup() at the appropriate time.
451 count = uart_circ_chars_pending(xmit);
452 if (count < (uap->fifosize >> 1)) {
453 uap->dmatx.queued = false;
458 * Bodge: don't send the last character by DMA, as this
459 * will prevent XON from notifying us to restart DMA.
463 /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */
464 if (count > PL011_DMA_BUFFER_SIZE)
465 count = PL011_DMA_BUFFER_SIZE;
467 if (xmit->tail < xmit->head)
468 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count);
470 size_t first = UART_XMIT_SIZE - xmit->tail;
471 size_t second = xmit->head;
473 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first);
475 memcpy(&dmatx->buf[first], &xmit->buf[0], second);
478 dmatx->sg.length = count;
480 if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) {
481 uap->dmatx.queued = false;
482 dev_dbg(uap->port.dev, "unable to map TX DMA\n");
486 desc = dmaengine_prep_slave_sg(chan, &dmatx->sg, 1, DMA_MEM_TO_DEV,
487 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
489 dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE);
490 uap->dmatx.queued = false;
492 * If DMA cannot be used right now, we complete this
493 * transaction via IRQ and let the TTY layer retry.
495 dev_dbg(uap->port.dev, "TX DMA busy\n");
499 /* Some data to go along to the callback */
500 desc->callback = pl011_dma_tx_callback;
501 desc->callback_param = uap;
503 /* All errors should happen at prepare time */
504 dmaengine_submit(desc);
506 /* Fire the DMA transaction */
507 dma_dev->device_issue_pending(chan);
509 uap->dmacr |= UART011_TXDMAE;
510 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
511 uap->dmatx.queued = true;
514 * Now we know that DMA will fire, so advance the ring buffer
515 * with the stuff we just dispatched.
517 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
518 uap->port.icount.tx += count;
520 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
521 uart_write_wakeup(&uap->port);
527 * We received a transmit interrupt without a pending X-char but with
528 * pending characters.
529 * Locking: called with port lock held and IRQs disabled.
531 * false if we want to use PIO to transmit
532 * true if we queued a DMA buffer
534 static bool pl011_dma_tx_irq(struct uart_amba_port *uap)
536 if (!uap->using_tx_dma)
540 * If we already have a TX buffer queued, but received a
541 * TX interrupt, it will be because we've just sent an X-char.
542 * Ensure the TX DMA is enabled and the TX IRQ is disabled.
544 if (uap->dmatx.queued) {
545 uap->dmacr |= UART011_TXDMAE;
546 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
547 uap->im &= ~UART011_TXIM;
548 writew(uap->im, uap->port.membase + UART011_IMSC);
553 * We don't have a TX buffer queued, so try to queue one.
554 * If we successfully queued a buffer, mask the TX IRQ.
556 if (pl011_dma_tx_refill(uap) > 0) {
557 uap->im &= ~UART011_TXIM;
558 writew(uap->im, uap->port.membase + UART011_IMSC);
565 * Stop the DMA transmit (eg, due to received XOFF).
566 * Locking: called with port lock held and IRQs disabled.
568 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
570 if (uap->dmatx.queued) {
571 uap->dmacr &= ~UART011_TXDMAE;
572 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
577 * Try to start a DMA transmit, or in the case of an XON/OFF
578 * character queued for send, try to get that character out ASAP.
579 * Locking: called with port lock held and IRQs disabled.
581 * false if we want the TX IRQ to be enabled
582 * true if we have a buffer queued
584 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
588 if (!uap->using_tx_dma)
591 if (!uap->port.x_char) {
592 /* no X-char, try to push chars out in DMA mode */
595 if (!uap->dmatx.queued) {
596 if (pl011_dma_tx_refill(uap) > 0) {
597 uap->im &= ~UART011_TXIM;
600 uap->im |= UART011_TXIM;
603 writew(uap->im, uap->port.membase + UART011_IMSC);
604 } else if (!(uap->dmacr & UART011_TXDMAE)) {
605 uap->dmacr |= UART011_TXDMAE;
607 uap->port.membase + UART011_DMACR);
613 * We have an X-char to send. Disable DMA to prevent it loading
614 * the TX fifo, and then see if we can stuff it into the FIFO.
617 uap->dmacr &= ~UART011_TXDMAE;
618 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
620 if (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) {
622 * No space in the FIFO, so enable the transmit interrupt
623 * so we know when there is space. Note that once we've
624 * loaded the character, we should just re-enable DMA.
629 writew(uap->port.x_char, uap->port.membase + UART01x_DR);
630 uap->port.icount.tx++;
631 uap->port.x_char = 0;
633 /* Success - restore the DMA state */
635 writew(dmacr, uap->port.membase + UART011_DMACR);
641 * Flush the transmit buffer.
642 * Locking: called with port lock held and IRQs disabled.
644 static void pl011_dma_flush_buffer(struct uart_port *port)
646 struct uart_amba_port *uap = (struct uart_amba_port *)port;
648 if (!uap->using_tx_dma)
651 /* Avoid deadlock with the DMA engine callback */
652 spin_unlock(&uap->port.lock);
653 dmaengine_terminate_all(uap->dmatx.chan);
654 spin_lock(&uap->port.lock);
655 if (uap->dmatx.queued) {
656 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
658 uap->dmatx.queued = false;
659 uap->dmacr &= ~UART011_TXDMAE;
660 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
664 static void pl011_dma_rx_callback(void *data);
666 static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
668 struct dma_chan *rxchan = uap->dmarx.chan;
669 struct pl011_dmarx_data *dmarx = &uap->dmarx;
670 struct dma_async_tx_descriptor *desc;
671 struct pl011_sgbuf *sgbuf;
676 /* Start the RX DMA job */
677 sgbuf = uap->dmarx.use_buf_b ?
678 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
679 desc = dmaengine_prep_slave_sg(rxchan, &sgbuf->sg, 1,
681 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
683 * If the DMA engine is busy and cannot prepare a
684 * channel, no big deal, the driver will fall back
685 * to interrupt mode as a result of this error code.
688 uap->dmarx.running = false;
689 dmaengine_terminate_all(rxchan);
693 /* Some data to go along to the callback */
694 desc->callback = pl011_dma_rx_callback;
695 desc->callback_param = uap;
696 dmarx->cookie = dmaengine_submit(desc);
697 dma_async_issue_pending(rxchan);
699 uap->dmacr |= UART011_RXDMAE;
700 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
701 uap->dmarx.running = true;
703 uap->im &= ~UART011_RXIM;
704 writew(uap->im, uap->port.membase + UART011_IMSC);
710 * This is called when either the DMA job is complete, or
711 * the FIFO timeout interrupt occurred. This must be called
712 * with the port spinlock uap->port.lock held.
714 static void pl011_dma_rx_chars(struct uart_amba_port *uap,
715 u32 pending, bool use_buf_b,
718 struct tty_struct *tty = uap->port.state->port.tty;
719 struct pl011_sgbuf *sgbuf = use_buf_b ?
720 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
721 struct device *dev = uap->dmarx.chan->device->dev;
723 u32 fifotaken = 0; /* only used for vdbg() */
725 /* Pick everything from the DMA first */
728 dma_sync_sg_for_cpu(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE);
731 * First take all chars in the DMA pipe, then look in the FIFO.
732 * Note that tty_insert_flip_buf() tries to take as many chars
735 dma_count = tty_insert_flip_string(uap->port.state->port.tty,
736 sgbuf->buf, pending);
738 /* Return buffer to device */
739 dma_sync_sg_for_device(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE);
741 uap->port.icount.rx += dma_count;
742 if (dma_count < pending)
743 dev_warn(uap->port.dev,
744 "couldn't insert all characters (TTY is full?)\n");
748 * Only continue with trying to read the FIFO if all DMA chars have
751 if (dma_count == pending && readfifo) {
752 /* Clear any error flags */
753 writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS,
754 uap->port.membase + UART011_ICR);
757 * If we read all the DMA'd characters, and we had an
758 * incomplete buffer, that could be due to an rx error, or
759 * maybe we just timed out. Read any pending chars and check
762 * Error conditions will only occur in the FIFO, these will
763 * trigger an immediate interrupt and stop the DMA job, so we
764 * will always find the error in the FIFO, never in the DMA
767 fifotaken = pl011_fifo_to_tty(uap);
770 spin_unlock(&uap->port.lock);
771 dev_vdbg(uap->port.dev,
772 "Took %d chars from DMA buffer and %d chars from the FIFO\n",
773 dma_count, fifotaken);
774 tty_flip_buffer_push(tty);
775 spin_lock(&uap->port.lock);
778 static void pl011_dma_rx_irq(struct uart_amba_port *uap)
780 struct pl011_dmarx_data *dmarx = &uap->dmarx;
781 struct dma_chan *rxchan = dmarx->chan;
782 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
783 &dmarx->sgbuf_b : &dmarx->sgbuf_a;
785 struct dma_tx_state state;
786 enum dma_status dmastat;
789 * Pause the transfer so we can trust the current counter,
790 * do this before we pause the PL011 block, else we may
793 if (dmaengine_pause(rxchan))
794 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
795 dmastat = rxchan->device->device_tx_status(rxchan,
796 dmarx->cookie, &state);
797 if (dmastat != DMA_PAUSED)
798 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
800 /* Disable RX DMA - incoming data will wait in the FIFO */
801 uap->dmacr &= ~UART011_RXDMAE;
802 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
803 uap->dmarx.running = false;
805 pending = sgbuf->sg.length - state.residue;
806 BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
807 /* Then we terminate the transfer - we now know our residue */
808 dmaengine_terminate_all(rxchan);
811 * This will take the chars we have so far and insert
812 * into the framework.
814 pl011_dma_rx_chars(uap, pending, dmarx->use_buf_b, true);
816 /* Switch buffer & re-trigger DMA job */
817 dmarx->use_buf_b = !dmarx->use_buf_b;
818 if (pl011_dma_rx_trigger_dma(uap)) {
819 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
820 "fall back to interrupt mode\n");
821 uap->im |= UART011_RXIM;
822 writew(uap->im, uap->port.membase + UART011_IMSC);
826 static void pl011_dma_rx_callback(void *data)
828 struct uart_amba_port *uap = data;
829 struct pl011_dmarx_data *dmarx = &uap->dmarx;
830 bool lastbuf = dmarx->use_buf_b;
834 * This completion interrupt occurs typically when the
835 * RX buffer is totally stuffed but no timeout has yet
836 * occurred. When that happens, we just want the RX
837 * routine to flush out the secondary DMA buffer while
838 * we immediately trigger the next DMA job.
840 spin_lock_irq(&uap->port.lock);
841 uap->dmarx.running = false;
842 dmarx->use_buf_b = !lastbuf;
843 ret = pl011_dma_rx_trigger_dma(uap);
845 pl011_dma_rx_chars(uap, PL011_DMA_BUFFER_SIZE, lastbuf, false);
846 spin_unlock_irq(&uap->port.lock);
848 * Do this check after we picked the DMA chars so we don't
849 * get some IRQ immediately from RX.
852 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
853 "fall back to interrupt mode\n");
854 uap->im |= UART011_RXIM;
855 writew(uap->im, uap->port.membase + UART011_IMSC);
860 * Stop accepting received characters, when we're shutting down or
861 * suspending this port.
862 * Locking: called with port lock held and IRQs disabled.
864 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
866 /* FIXME. Just disable the DMA enable */
867 uap->dmacr &= ~UART011_RXDMAE;
868 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
871 static void pl011_dma_startup(struct uart_amba_port *uap)
875 if (!uap->dmatx.chan)
878 uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL);
879 if (!uap->dmatx.buf) {
880 dev_err(uap->port.dev, "no memory for DMA TX buffer\n");
881 uap->port.fifosize = uap->fifosize;
885 sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE);
887 /* The DMA buffer is now the FIFO the TTY subsystem can use */
888 uap->port.fifosize = PL011_DMA_BUFFER_SIZE;
889 uap->using_tx_dma = true;
891 if (!uap->dmarx.chan)
894 /* Allocate and map DMA RX buffers */
895 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
898 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
903 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_b,
906 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
908 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
913 uap->using_rx_dma = true;
916 /* Turn on DMA error (RX/TX will be enabled on demand) */
917 uap->dmacr |= UART011_DMAONERR;
918 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
921 * ST Micro variants has some specific dma burst threshold
922 * compensation. Set this to 16 bytes, so burst will only
923 * be issued above/below 16 bytes.
925 if (uap->vendor->dma_threshold)
926 writew(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16,
927 uap->port.membase + ST_UART011_DMAWM);
929 if (uap->using_rx_dma) {
930 if (pl011_dma_rx_trigger_dma(uap))
931 dev_dbg(uap->port.dev, "could not trigger initial "
932 "RX DMA job, fall back to interrupt mode\n");
936 static void pl011_dma_shutdown(struct uart_amba_port *uap)
938 if (!(uap->using_tx_dma || uap->using_rx_dma))
941 /* Disable RX and TX DMA */
942 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
945 spin_lock_irq(&uap->port.lock);
946 uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE);
947 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
948 spin_unlock_irq(&uap->port.lock);
950 if (uap->using_tx_dma) {
951 /* In theory, this should already be done by pl011_dma_flush_buffer */
952 dmaengine_terminate_all(uap->dmatx.chan);
953 if (uap->dmatx.queued) {
954 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
956 uap->dmatx.queued = false;
959 kfree(uap->dmatx.buf);
960 uap->using_tx_dma = false;
963 if (uap->using_rx_dma) {
964 dmaengine_terminate_all(uap->dmarx.chan);
965 /* Clean up the RX DMA */
966 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, DMA_FROM_DEVICE);
967 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_b, DMA_FROM_DEVICE);
968 uap->using_rx_dma = false;
972 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
974 return uap->using_rx_dma;
977 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
979 return uap->using_rx_dma && uap->dmarx.running;
984 /* Blank functions if the DMA engine is not available */
985 static inline void pl011_dma_probe(struct uart_amba_port *uap)
989 static inline void pl011_dma_remove(struct uart_amba_port *uap)
993 static inline void pl011_dma_startup(struct uart_amba_port *uap)
997 static inline void pl011_dma_shutdown(struct uart_amba_port *uap)
1001 static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap)
1006 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
1010 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
1015 static inline void pl011_dma_rx_irq(struct uart_amba_port *uap)
1019 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
1023 static inline int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
1028 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
1033 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
1038 #define pl011_dma_flush_buffer NULL
1044 * This workaround aims to break the deadlock situation
1045 * when after long transfer over uart in hardware flow
1046 * control, uart interrupt registers cannot be cleared.
1047 * Hence uart transfer gets blocked.
1049 * It is seen that during such deadlock condition ICR
1050 * don't get cleared even on multiple write. This leads
1051 * pass_counter to decrease and finally reach zero. This
1052 * can be taken as trigger point to run this UART_BT_WA.
1055 static void pl011_lockup_wa(unsigned long data)
1057 struct uart_amba_port *uap = amba_ports[0];
1058 void __iomem *base = uap->port.membase;
1059 struct circ_buf *xmit = &uap->port.state->xmit;
1060 struct tty_struct *tty = uap->port.state->port.tty;
1061 int buf_empty_retries = 200;
1064 /* Stop HCI layer from submitting data for tx */
1065 tty->hw_stopped = 1;
1066 while (!uart_circ_empty(xmit)) {
1067 if (buf_empty_retries-- == 0)
1072 /* Backup registers */
1073 for (loop = 0; loop < UART_WA_SAVE_NR; loop++)
1074 uart_wa_regdata[loop] = readl(base + uart_wa_reg[loop]);
1076 /* Disable UART so that FIFO data is flushed out */
1077 writew(0x00, uap->port.membase + UART011_CR);
1079 /* Soft reset UART module */
1080 if (uap->port.dev->platform_data) {
1081 struct amba_pl011_data *plat;
1083 plat = uap->port.dev->platform_data;
1088 /* Restore registers */
1089 for (loop = 0; loop < UART_WA_SAVE_NR; loop++)
1090 writew(uart_wa_regdata[loop] ,
1091 uap->port.membase + uart_wa_reg[loop]);
1093 /* Initialise the old status of the modem signals */
1094 uap->old_status = readw(uap->port.membase + UART01x_FR) &
1095 UART01x_FR_MODEM_ANY;
1097 if (readl(base + UART011_MIS) & 0x2)
1098 printk(KERN_EMERG "UART_BT_WA: ***FAILED***\n");
1101 tty->hw_stopped = 0;
1104 static void pl011_stop_tx(struct uart_port *port)
1106 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1108 uap->im &= ~UART011_TXIM;
1109 writew(uap->im, uap->port.membase + UART011_IMSC);
1110 pl011_dma_tx_stop(uap);
1113 static void pl011_start_tx(struct uart_port *port)
1115 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1117 if (!pl011_dma_tx_start(uap)) {
1118 uap->im |= UART011_TXIM;
1119 writew(uap->im, uap->port.membase + UART011_IMSC);
1123 static void pl011_stop_rx(struct uart_port *port)
1125 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1127 uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM|
1128 UART011_PEIM|UART011_BEIM|UART011_OEIM);
1129 writew(uap->im, uap->port.membase + UART011_IMSC);
1131 pl011_dma_rx_stop(uap);
1134 static void pl011_enable_ms(struct uart_port *port)
1136 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1138 uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM;
1139 writew(uap->im, uap->port.membase + UART011_IMSC);
1142 static void pl011_rx_chars(struct uart_amba_port *uap)
1144 struct tty_struct *tty = uap->port.state->port.tty;
1146 pl011_fifo_to_tty(uap);
1148 spin_unlock(&uap->port.lock);
1149 tty_flip_buffer_push(tty);
1151 * If we were temporarily out of DMA mode for a while,
1152 * attempt to switch back to DMA mode again.
1154 if (pl011_dma_rx_available(uap)) {
1155 if (pl011_dma_rx_trigger_dma(uap)) {
1156 dev_dbg(uap->port.dev, "could not trigger RX DMA job "
1157 "fall back to interrupt mode again\n");
1158 uap->im |= UART011_RXIM;
1160 uap->im &= ~UART011_RXIM;
1161 writew(uap->im, uap->port.membase + UART011_IMSC);
1163 spin_lock(&uap->port.lock);
1166 static void pl011_tx_chars(struct uart_amba_port *uap)
1168 struct circ_buf *xmit = &uap->port.state->xmit;
1171 if (uap->port.x_char) {
1172 writew(uap->port.x_char, uap->port.membase + UART01x_DR);
1173 uap->port.icount.tx++;
1174 uap->port.x_char = 0;
1177 if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
1178 pl011_stop_tx(&uap->port);
1182 /* If we are using DMA mode, try to send some characters. */
1183 if (pl011_dma_tx_irq(uap))
1186 count = uap->fifosize >> 1;
1188 writew(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
1189 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
1190 uap->port.icount.tx++;
1191 if (uart_circ_empty(xmit))
1193 } while (--count > 0);
1195 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1196 uart_write_wakeup(&uap->port);
1198 if (uart_circ_empty(xmit))
1199 pl011_stop_tx(&uap->port);
1202 static void pl011_modem_status(struct uart_amba_port *uap)
1204 unsigned int status, delta;
1206 status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
1208 delta = status ^ uap->old_status;
1209 uap->old_status = status;
1214 if (delta & UART01x_FR_DCD)
1215 uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
1217 if (delta & UART01x_FR_DSR)
1218 uap->port.icount.dsr++;
1220 if (delta & UART01x_FR_CTS)
1221 uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
1223 wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
1226 static irqreturn_t pl011_int(int irq, void *dev_id)
1228 struct uart_amba_port *uap = dev_id;
1229 unsigned long flags;
1230 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
1233 spin_lock_irqsave(&uap->port.lock, flags);
1235 status = readw(uap->port.membase + UART011_MIS);
1238 writew(status & ~(UART011_TXIS|UART011_RTIS|
1240 uap->port.membase + UART011_ICR);
1242 if (status & (UART011_RTIS|UART011_RXIS)) {
1243 if (pl011_dma_rx_running(uap))
1244 pl011_dma_rx_irq(uap);
1246 pl011_rx_chars(uap);
1248 if (status & (UART011_DSRMIS|UART011_DCDMIS|
1249 UART011_CTSMIS|UART011_RIMIS))
1250 pl011_modem_status(uap);
1251 if (status & UART011_TXIS)
1252 pl011_tx_chars(uap);
1254 if (pass_counter-- == 0) {
1255 if (uap->interrupt_may_hang)
1256 tasklet_schedule(&pl011_lockup_tlet);
1260 status = readw(uap->port.membase + UART011_MIS);
1261 } while (status != 0);
1265 spin_unlock_irqrestore(&uap->port.lock, flags);
1267 return IRQ_RETVAL(handled);
1270 static unsigned int pl01x_tx_empty(struct uart_port *port)
1272 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1273 unsigned int status = readw(uap->port.membase + UART01x_FR);
1274 return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT;
1277 static unsigned int pl01x_get_mctrl(struct uart_port *port)
1279 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1280 unsigned int result = 0;
1281 unsigned int status = readw(uap->port.membase + UART01x_FR);
1283 #define TIOCMBIT(uartbit, tiocmbit) \
1284 if (status & uartbit) \
1287 TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR);
1288 TIOCMBIT(UART01x_FR_DSR, TIOCM_DSR);
1289 TIOCMBIT(UART01x_FR_CTS, TIOCM_CTS);
1290 TIOCMBIT(UART011_FR_RI, TIOCM_RNG);
1295 static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl)
1297 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1300 cr = readw(uap->port.membase + UART011_CR);
1302 #define TIOCMBIT(tiocmbit, uartbit) \
1303 if (mctrl & tiocmbit) \
1308 TIOCMBIT(TIOCM_RTS, UART011_CR_RTS);
1309 TIOCMBIT(TIOCM_DTR, UART011_CR_DTR);
1310 TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1);
1311 TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2);
1312 TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE);
1315 /* We need to disable auto-RTS if we want to turn RTS off */
1316 TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN);
1320 writew(cr, uap->port.membase + UART011_CR);
1323 static void pl011_break_ctl(struct uart_port *port, int break_state)
1325 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1326 unsigned long flags;
1329 spin_lock_irqsave(&uap->port.lock, flags);
1330 lcr_h = readw(uap->port.membase + uap->lcrh_tx);
1331 if (break_state == -1)
1332 lcr_h |= UART01x_LCRH_BRK;
1334 lcr_h &= ~UART01x_LCRH_BRK;
1335 writew(lcr_h, uap->port.membase + uap->lcrh_tx);
1336 spin_unlock_irqrestore(&uap->port.lock, flags);
1339 #ifdef CONFIG_CONSOLE_POLL
1340 static int pl010_get_poll_char(struct uart_port *port)
1342 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1343 unsigned int status;
1345 status = readw(uap->port.membase + UART01x_FR);
1346 if (status & UART01x_FR_RXFE)
1347 return NO_POLL_CHAR;
1349 return readw(uap->port.membase + UART01x_DR);
1352 static void pl010_put_poll_char(struct uart_port *port,
1355 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1357 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
1360 writew(ch, uap->port.membase + UART01x_DR);
1363 #endif /* CONFIG_CONSOLE_POLL */
1365 static int pl011_startup(struct uart_port *port)
1367 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1371 retval = clk_prepare(uap->clk);
1376 * Try to enable the clock producer.
1378 retval = clk_enable(uap->clk);
1382 uap->port.uartclk = clk_get_rate(uap->clk);
1387 retval = request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap);
1391 writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS);
1394 * Provoke TX FIFO interrupt into asserting.
1396 cr = UART01x_CR_UARTEN | UART011_CR_TXE | UART011_CR_LBE;
1397 writew(cr, uap->port.membase + UART011_CR);
1398 writew(0, uap->port.membase + UART011_FBRD);
1399 writew(1, uap->port.membase + UART011_IBRD);
1400 writew(0, uap->port.membase + uap->lcrh_rx);
1401 if (uap->lcrh_tx != uap->lcrh_rx) {
1404 * Wait 10 PCLKs before writing LCRH_TX register,
1405 * to get this delay write read only register 10 times
1407 for (i = 0; i < 10; ++i)
1408 writew(0xff, uap->port.membase + UART011_MIS);
1409 writew(0, uap->port.membase + uap->lcrh_tx);
1411 writew(0, uap->port.membase + UART01x_DR);
1412 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
1415 cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
1416 writew(cr, uap->port.membase + UART011_CR);
1418 /* Clear pending error interrupts */
1419 writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS,
1420 uap->port.membase + UART011_ICR);
1423 * initialise the old status of the modem signals
1425 uap->old_status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
1428 pl011_dma_startup(uap);
1431 * Finally, enable interrupts, only timeouts when using DMA
1432 * if initial RX DMA job failed, start in interrupt mode
1435 spin_lock_irq(&uap->port.lock);
1436 uap->im = UART011_RTIM;
1437 if (!pl011_dma_rx_running(uap))
1438 uap->im |= UART011_RXIM;
1439 writew(uap->im, uap->port.membase + UART011_IMSC);
1440 spin_unlock_irq(&uap->port.lock);
1442 if (uap->port.dev->platform_data) {
1443 struct amba_pl011_data *plat;
1445 plat = uap->port.dev->platform_data;
1453 clk_disable(uap->clk);
1455 clk_unprepare(uap->clk);
1460 static void pl011_shutdown_channel(struct uart_amba_port *uap,
1465 val = readw(uap->port.membase + lcrh);
1466 val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN);
1467 writew(val, uap->port.membase + lcrh);
1470 static void pl011_shutdown(struct uart_port *port)
1472 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1475 * disable all interrupts
1477 spin_lock_irq(&uap->port.lock);
1479 writew(uap->im, uap->port.membase + UART011_IMSC);
1480 writew(0xffff, uap->port.membase + UART011_ICR);
1481 spin_unlock_irq(&uap->port.lock);
1483 pl011_dma_shutdown(uap);
1486 * Free the interrupt
1488 free_irq(uap->port.irq, uap);
1493 uap->autorts = false;
1494 writew(UART01x_CR_UARTEN | UART011_CR_TXE, uap->port.membase + UART011_CR);
1497 * disable break condition and fifos
1499 pl011_shutdown_channel(uap, uap->lcrh_rx);
1500 if (uap->lcrh_rx != uap->lcrh_tx)
1501 pl011_shutdown_channel(uap, uap->lcrh_tx);
1504 * Shut down the clock producer
1506 clk_disable(uap->clk);
1507 clk_unprepare(uap->clk);
1509 if (uap->port.dev->platform_data) {
1510 struct amba_pl011_data *plat;
1512 plat = uap->port.dev->platform_data;
1520 pl011_set_termios(struct uart_port *port, struct ktermios *termios,
1521 struct ktermios *old)
1523 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1524 unsigned int lcr_h, old_cr;
1525 unsigned long flags;
1526 unsigned int baud, quot, clkdiv;
1528 if (uap->vendor->oversampling)
1534 * Ask the core to calculate the divisor for us.
1536 baud = uart_get_baud_rate(port, termios, old, 0,
1537 port->uartclk / clkdiv);
1539 if (baud > port->uartclk/16)
1540 quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud);
1542 quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud);
1544 switch (termios->c_cflag & CSIZE) {
1546 lcr_h = UART01x_LCRH_WLEN_5;
1549 lcr_h = UART01x_LCRH_WLEN_6;
1552 lcr_h = UART01x_LCRH_WLEN_7;
1555 lcr_h = UART01x_LCRH_WLEN_8;
1558 if (termios->c_cflag & CSTOPB)
1559 lcr_h |= UART01x_LCRH_STP2;
1560 if (termios->c_cflag & PARENB) {
1561 lcr_h |= UART01x_LCRH_PEN;
1562 if (!(termios->c_cflag & PARODD))
1563 lcr_h |= UART01x_LCRH_EPS;
1565 if (uap->fifosize > 1)
1566 lcr_h |= UART01x_LCRH_FEN;
1568 spin_lock_irqsave(&port->lock, flags);
1571 * Update the per-port timeout.
1573 uart_update_timeout(port, termios->c_cflag, baud);
1575 port->read_status_mask = UART011_DR_OE | 255;
1576 if (termios->c_iflag & INPCK)
1577 port->read_status_mask |= UART011_DR_FE | UART011_DR_PE;
1578 if (termios->c_iflag & (BRKINT | PARMRK))
1579 port->read_status_mask |= UART011_DR_BE;
1582 * Characters to ignore
1584 port->ignore_status_mask = 0;
1585 if (termios->c_iflag & IGNPAR)
1586 port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE;
1587 if (termios->c_iflag & IGNBRK) {
1588 port->ignore_status_mask |= UART011_DR_BE;
1590 * If we're ignoring parity and break indicators,
1591 * ignore overruns too (for real raw support).
1593 if (termios->c_iflag & IGNPAR)
1594 port->ignore_status_mask |= UART011_DR_OE;
1598 * Ignore all characters if CREAD is not set.
1600 if ((termios->c_cflag & CREAD) == 0)
1601 port->ignore_status_mask |= UART_DUMMY_DR_RX;
1603 if (UART_ENABLE_MS(port, termios->c_cflag))
1604 pl011_enable_ms(port);
1606 /* first, disable everything */
1607 old_cr = readw(port->membase + UART011_CR);
1608 writew(0, port->membase + UART011_CR);
1610 if (termios->c_cflag & CRTSCTS) {
1611 if (old_cr & UART011_CR_RTS)
1612 old_cr |= UART011_CR_RTSEN;
1614 old_cr |= UART011_CR_CTSEN;
1615 uap->autorts = true;
1617 old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN);
1618 uap->autorts = false;
1621 if (uap->vendor->oversampling) {
1622 if (baud > port->uartclk / 16)
1623 old_cr |= ST_UART011_CR_OVSFACT;
1625 old_cr &= ~ST_UART011_CR_OVSFACT;
1629 writew(quot & 0x3f, port->membase + UART011_FBRD);
1630 writew(quot >> 6, port->membase + UART011_IBRD);
1633 * ----------v----------v----------v----------v-----
1634 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
1635 * ----------^----------^----------^----------^-----
1637 writew(lcr_h, port->membase + uap->lcrh_rx);
1638 if (uap->lcrh_rx != uap->lcrh_tx) {
1641 * Wait 10 PCLKs before writing LCRH_TX register,
1642 * to get this delay write read only register 10 times
1644 for (i = 0; i < 10; ++i)
1645 writew(0xff, uap->port.membase + UART011_MIS);
1646 writew(lcr_h, port->membase + uap->lcrh_tx);
1648 writew(old_cr, port->membase + UART011_CR);
1650 spin_unlock_irqrestore(&port->lock, flags);
1653 static const char *pl011_type(struct uart_port *port)
1655 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1656 return uap->port.type == PORT_AMBA ? uap->type : NULL;
1660 * Release the memory region(s) being used by 'port'
1662 static void pl010_release_port(struct uart_port *port)
1664 release_mem_region(port->mapbase, SZ_4K);
1668 * Request the memory region(s) being used by 'port'
1670 static int pl010_request_port(struct uart_port *port)
1672 return request_mem_region(port->mapbase, SZ_4K, "uart-pl011")
1673 != NULL ? 0 : -EBUSY;
1677 * Configure/autoconfigure the port.
1679 static void pl010_config_port(struct uart_port *port, int flags)
1681 if (flags & UART_CONFIG_TYPE) {
1682 port->type = PORT_AMBA;
1683 pl010_request_port(port);
1688 * verify the new serial_struct (for TIOCSSERIAL).
1690 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
1693 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
1695 if (ser->irq < 0 || ser->irq >= nr_irqs)
1697 if (ser->baud_base < 9600)
1702 static struct uart_ops amba_pl011_pops = {
1703 .tx_empty = pl01x_tx_empty,
1704 .set_mctrl = pl011_set_mctrl,
1705 .get_mctrl = pl01x_get_mctrl,
1706 .stop_tx = pl011_stop_tx,
1707 .start_tx = pl011_start_tx,
1708 .stop_rx = pl011_stop_rx,
1709 .enable_ms = pl011_enable_ms,
1710 .break_ctl = pl011_break_ctl,
1711 .startup = pl011_startup,
1712 .shutdown = pl011_shutdown,
1713 .flush_buffer = pl011_dma_flush_buffer,
1714 .set_termios = pl011_set_termios,
1716 .release_port = pl010_release_port,
1717 .request_port = pl010_request_port,
1718 .config_port = pl010_config_port,
1719 .verify_port = pl010_verify_port,
1720 #ifdef CONFIG_CONSOLE_POLL
1721 .poll_get_char = pl010_get_poll_char,
1722 .poll_put_char = pl010_put_poll_char,
1726 static struct uart_amba_port *amba_ports[UART_NR];
1728 #ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE
1730 static void pl011_console_putchar(struct uart_port *port, int ch)
1732 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1734 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
1736 writew(ch, uap->port.membase + UART01x_DR);
1740 pl011_console_write(struct console *co, const char *s, unsigned int count)
1742 struct uart_amba_port *uap = amba_ports[co->index];
1743 unsigned int status, old_cr, new_cr;
1745 clk_enable(uap->clk);
1748 * First save the CR then disable the interrupts
1750 old_cr = readw(uap->port.membase + UART011_CR);
1751 new_cr = old_cr & ~UART011_CR_CTSEN;
1752 new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
1753 writew(new_cr, uap->port.membase + UART011_CR);
1755 uart_console_write(&uap->port, s, count, pl011_console_putchar);
1758 * Finally, wait for transmitter to become empty
1759 * and restore the TCR
1762 status = readw(uap->port.membase + UART01x_FR);
1763 } while (status & UART01x_FR_BUSY);
1764 writew(old_cr, uap->port.membase + UART011_CR);
1766 clk_disable(uap->clk);
1770 pl011_console_get_options(struct uart_amba_port *uap, int *baud,
1771 int *parity, int *bits)
1773 if (readw(uap->port.membase + UART011_CR) & UART01x_CR_UARTEN) {
1774 unsigned int lcr_h, ibrd, fbrd;
1776 lcr_h = readw(uap->port.membase + uap->lcrh_tx);
1779 if (lcr_h & UART01x_LCRH_PEN) {
1780 if (lcr_h & UART01x_LCRH_EPS)
1786 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
1791 ibrd = readw(uap->port.membase + UART011_IBRD);
1792 fbrd = readw(uap->port.membase + UART011_FBRD);
1794 *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd);
1796 if (uap->vendor->oversampling) {
1797 if (readw(uap->port.membase + UART011_CR)
1798 & ST_UART011_CR_OVSFACT)
1804 static int __init pl011_console_setup(struct console *co, char *options)
1806 struct uart_amba_port *uap;
1814 * Check whether an invalid uart number has been specified, and
1815 * if so, search for the first available port that does have
1818 if (co->index >= UART_NR)
1820 uap = amba_ports[co->index];
1824 ret = clk_prepare(uap->clk);
1828 if (uap->port.dev->platform_data) {
1829 struct amba_pl011_data *plat;
1831 plat = uap->port.dev->platform_data;
1836 uap->port.uartclk = clk_get_rate(uap->clk);
1839 uart_parse_options(options, &baud, &parity, &bits, &flow);
1841 pl011_console_get_options(uap, &baud, &parity, &bits);
1843 return uart_set_options(&uap->port, co, baud, parity, bits, flow);
1846 static struct uart_driver amba_reg;
1847 static struct console amba_console = {
1849 .write = pl011_console_write,
1850 .device = uart_console_device,
1851 .setup = pl011_console_setup,
1852 .flags = CON_PRINTBUFFER,
1857 #define AMBA_CONSOLE (&amba_console)
1859 #define AMBA_CONSOLE NULL
1862 static struct uart_driver amba_reg = {
1863 .owner = THIS_MODULE,
1864 .driver_name = "ttyAMA",
1865 .dev_name = "ttyAMA",
1866 .major = SERIAL_AMBA_MAJOR,
1867 .minor = SERIAL_AMBA_MINOR,
1869 .cons = AMBA_CONSOLE,
1872 static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
1874 struct uart_amba_port *uap;
1875 struct vendor_data *vendor = id->data;
1879 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
1880 if (amba_ports[i] == NULL)
1883 if (i == ARRAY_SIZE(amba_ports)) {
1888 uap = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
1894 base = ioremap(dev->res.start, resource_size(&dev->res));
1900 uap->clk = clk_get(&dev->dev, NULL);
1901 if (IS_ERR(uap->clk)) {
1902 ret = PTR_ERR(uap->clk);
1906 uap->vendor = vendor;
1907 uap->lcrh_rx = vendor->lcrh_rx;
1908 uap->lcrh_tx = vendor->lcrh_tx;
1909 uap->fifosize = vendor->fifosize;
1910 uap->interrupt_may_hang = vendor->interrupt_may_hang;
1911 uap->port.dev = &dev->dev;
1912 uap->port.mapbase = dev->res.start;
1913 uap->port.membase = base;
1914 uap->port.iotype = UPIO_MEM;
1915 uap->port.irq = dev->irq[0];
1916 uap->port.fifosize = uap->fifosize;
1917 uap->port.ops = &amba_pl011_pops;
1918 uap->port.flags = UPF_BOOT_AUTOCONF;
1920 pl011_dma_probe(uap);
1922 snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
1924 amba_ports[i] = uap;
1926 amba_set_drvdata(dev, uap);
1927 ret = uart_add_one_port(&amba_reg, &uap->port);
1929 amba_set_drvdata(dev, NULL);
1930 amba_ports[i] = NULL;
1931 pl011_dma_remove(uap);
1942 static int pl011_remove(struct amba_device *dev)
1944 struct uart_amba_port *uap = amba_get_drvdata(dev);
1947 amba_set_drvdata(dev, NULL);
1949 uart_remove_one_port(&amba_reg, &uap->port);
1951 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
1952 if (amba_ports[i] == uap)
1953 amba_ports[i] = NULL;
1955 pl011_dma_remove(uap);
1956 iounmap(uap->port.membase);
1963 static int pl011_suspend(struct amba_device *dev, pm_message_t state)
1965 struct uart_amba_port *uap = amba_get_drvdata(dev);
1970 return uart_suspend_port(&amba_reg, &uap->port);
1973 static int pl011_resume(struct amba_device *dev)
1975 struct uart_amba_port *uap = amba_get_drvdata(dev);
1980 return uart_resume_port(&amba_reg, &uap->port);
1984 static struct amba_id pl011_ids[] = {
1988 .data = &vendor_arm,
1998 MODULE_DEVICE_TABLE(amba, pl011_ids);
2000 static struct amba_driver pl011_driver = {
2002 .name = "uart-pl011",
2004 .id_table = pl011_ids,
2005 .probe = pl011_probe,
2006 .remove = pl011_remove,
2008 .suspend = pl011_suspend,
2009 .resume = pl011_resume,
2013 static int __init pl011_init(void)
2016 printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");
2018 ret = uart_register_driver(&amba_reg);
2020 ret = amba_driver_register(&pl011_driver);
2022 uart_unregister_driver(&amba_reg);
2027 static void __exit pl011_exit(void)
2029 amba_driver_unregister(&pl011_driver);
2030 uart_unregister_driver(&amba_reg);
2034 * While this can be a module, if builtin it's most likely the console
2035 * So let's leave module_exit but move module_init to an earlier place
2037 arch_initcall(pl011_init);
2038 module_exit(pl011_exit);
2040 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
2041 MODULE_DESCRIPTION("ARM AMBA serial port driver");
2042 MODULE_LICENSE("GPL");