2 * Synopsys DesignWare 8250 driver.
4 * Copyright 2011 Picochip, Jamie Iles.
5 * Copyright 2013 Intel Corporation
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * The Synopsys DesignWare 8250 has an extra feature whereby it detects if the
13 * LCR is written whilst busy. If it is, then a busy detect interrupt is
14 * raised, the LCR needs to be rewritten and the uart status register read.
16 #include <linux/device.h>
18 #include <linux/module.h>
19 #include <linux/serial_8250.h>
20 #include <linux/serial_reg.h>
22 #include <linux/of_irq.h>
23 #include <linux/of_platform.h>
24 #include <linux/platform_device.h>
25 #include <linux/slab.h>
26 #include <linux/acpi.h>
27 #include <linux/clk.h>
28 #include <linux/reset.h>
29 #include <linux/pm_runtime.h>
31 #include <asm/byteorder.h>
35 /* Offsets for the DesignWare specific registers */
36 #define DW_UART_USR 0x1f /* UART Status Register */
37 #define DW_UART_CPR 0xf4 /* Component Parameter Register */
38 #define DW_UART_UCV 0xf8 /* UART Component Version */
40 /* Component Parameter Register bits */
41 #define DW_UART_CPR_ABP_DATA_WIDTH (3 << 0)
42 #define DW_UART_CPR_AFCE_MODE (1 << 4)
43 #define DW_UART_CPR_THRE_MODE (1 << 5)
44 #define DW_UART_CPR_SIR_MODE (1 << 6)
45 #define DW_UART_CPR_SIR_LP_MODE (1 << 7)
46 #define DW_UART_CPR_ADDITIONAL_FEATURES (1 << 8)
47 #define DW_UART_CPR_FIFO_ACCESS (1 << 9)
48 #define DW_UART_CPR_FIFO_STAT (1 << 10)
49 #define DW_UART_CPR_SHADOW (1 << 11)
50 #define DW_UART_CPR_ENCODED_PARMS (1 << 12)
51 #define DW_UART_CPR_DMA_EXTRA (1 << 13)
52 #define DW_UART_CPR_FIFO_MODE (0xff << 16)
53 /* Helper for fifo size calculation */
54 #define DW_UART_CPR_FIFO_SIZE(a) (((a >> 16) & 0xff) * 16)
56 /* DesignWare specific register fields */
57 #define DW_UART_MCR_SIRE BIT(6)
66 struct reset_control *rst;
67 struct uart_8250_dma dma;
69 unsigned int skip_autocfg:1;
70 unsigned int uart_16550_compatible:1;
73 static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
75 struct dw8250_data *d = p->private_data;
77 /* Override any modem control signals if needed */
78 if (offset == UART_MSR) {
79 value |= d->msr_mask_on;
80 value &= ~d->msr_mask_off;
86 static void dw8250_force_idle(struct uart_port *p)
88 struct uart_8250_port *up = up_to_u8250p(p);
90 serial8250_clear_and_reinit_fifos(up);
91 (void)p->serial_in(p, UART_RX);
94 static void dw8250_check_lcr(struct uart_port *p, int value)
96 void __iomem *offset = p->membase + (UART_LCR << p->regshift);
99 /* Make sure LCR write wasn't ignored */
101 unsigned int lcr = p->serial_in(p, UART_LCR);
103 if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
106 dw8250_force_idle(p);
109 if (p->type == PORT_OCTEON)
110 __raw_writeq(value & 0xff, offset);
113 if (p->iotype == UPIO_MEM32)
114 writel(value, offset);
115 else if (p->iotype == UPIO_MEM32BE)
116 iowrite32be(value, offset);
118 writeb(value, offset);
121 * FIXME: this deadlocks if port->lock is already held
122 * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
126 static void dw8250_serial_out(struct uart_port *p, int offset, int value)
128 struct dw8250_data *d = p->private_data;
130 writeb(value, p->membase + (offset << p->regshift));
132 if (offset == UART_LCR && !d->uart_16550_compatible)
133 dw8250_check_lcr(p, value);
136 static unsigned int dw8250_serial_in(struct uart_port *p, int offset)
138 unsigned int value = readb(p->membase + (offset << p->regshift));
140 return dw8250_modify_msr(p, offset, value);
144 static unsigned int dw8250_serial_inq(struct uart_port *p, int offset)
148 value = (u8)__raw_readq(p->membase + (offset << p->regshift));
150 return dw8250_modify_msr(p, offset, value);
153 static void dw8250_serial_outq(struct uart_port *p, int offset, int value)
155 struct dw8250_data *d = p->private_data;
158 __raw_writeq(value, p->membase + (offset << p->regshift));
159 /* Read back to ensure register write ordering. */
160 __raw_readq(p->membase + (UART_LCR << p->regshift));
162 if (offset == UART_LCR && !d->uart_16550_compatible)
163 dw8250_check_lcr(p, value);
165 #endif /* CONFIG_64BIT */
167 static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
169 struct dw8250_data *d = p->private_data;
171 writel(value, p->membase + (offset << p->regshift));
173 if (offset == UART_LCR && !d->uart_16550_compatible)
174 dw8250_check_lcr(p, value);
177 static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
179 unsigned int value = readl(p->membase + (offset << p->regshift));
181 return dw8250_modify_msr(p, offset, value);
184 static void dw8250_serial_out32be(struct uart_port *p, int offset, int value)
186 struct dw8250_data *d = p->private_data;
188 iowrite32be(value, p->membase + (offset << p->regshift));
190 if (offset == UART_LCR && !d->uart_16550_compatible)
191 dw8250_check_lcr(p, value);
194 static unsigned int dw8250_serial_in32be(struct uart_port *p, int offset)
196 unsigned int value = ioread32be(p->membase + (offset << p->regshift));
198 return dw8250_modify_msr(p, offset, value);
202 static int dw8250_handle_irq(struct uart_port *p)
204 struct uart_8250_port *up = up_to_u8250p(p);
205 struct dw8250_data *d = p->private_data;
206 unsigned int iir = p->serial_in(p, UART_IIR);
211 * There are ways to get Designware-based UARTs into a state where
212 * they are asserting UART_IIR_RX_TIMEOUT but there is no actual
213 * data available. If we see such a case then we'll do a bogus
214 * read. If we don't do this then the "RX TIMEOUT" interrupt will
217 * This problem has only been observed so far when not in DMA mode
218 * so we limit the workaround only to non-DMA mode.
220 if (!up->dma && ((iir & 0x3f) == UART_IIR_RX_TIMEOUT)) {
221 spin_lock_irqsave(&p->lock, flags);
222 status = p->serial_in(p, UART_LSR);
224 if (!(status & (UART_LSR_DR | UART_LSR_BI)))
225 (void) p->serial_in(p, UART_RX);
227 spin_unlock_irqrestore(&p->lock, flags);
230 if (serial8250_handle_irq(p, iir))
233 if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
235 (void)p->serial_in(p, d->usr_reg);
244 dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
247 pm_runtime_get_sync(port->dev);
249 serial8250_do_pm(port, state, old);
252 pm_runtime_put_sync_suspend(port->dev);
255 static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
256 struct ktermios *old)
258 unsigned int baud = tty_termios_baud_rate(termios);
259 struct dw8250_data *d = p->private_data;
263 if (IS_ERR(d->clk) || !old)
266 clk_disable_unprepare(d->clk);
267 rate = clk_round_rate(d->clk, baud * 16);
268 ret = clk_set_rate(d->clk, rate);
269 clk_prepare_enable(d->clk);
275 p->status &= ~UPSTAT_AUTOCTS;
276 if (termios->c_cflag & CRTSCTS)
277 p->status |= UPSTAT_AUTOCTS;
279 serial8250_do_set_termios(p, termios, old);
282 static void dw8250_set_ldisc(struct uart_port *p, struct ktermios *termios)
284 struct uart_8250_port *up = up_to_u8250p(p);
285 unsigned int mcr = p->serial_in(p, UART_MCR);
287 if (up->capabilities & UART_CAP_IRDA) {
288 if (termios->c_line == N_IRDA)
289 mcr |= DW_UART_MCR_SIRE;
291 mcr &= ~DW_UART_MCR_SIRE;
293 p->serial_out(p, UART_MCR, mcr);
295 serial8250_do_set_ldisc(p, termios);
299 * dw8250_fallback_dma_filter will prevent the UART from getting just any free
300 * channel on platforms that have DMA engines, but don't have any channels
301 * assigned to the UART.
303 * REVISIT: This is a work around for limitation in the DMA Engine API. Once the
304 * core problem is fixed, this function is no longer needed.
306 static bool dw8250_fallback_dma_filter(struct dma_chan *chan, void *param)
311 static bool dw8250_idma_filter(struct dma_chan *chan, void *param)
313 return param == chan->device->dev->parent;
316 static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data)
318 if (p->dev->of_node) {
319 struct device_node *np = p->dev->of_node;
322 /* get index of serial line, if found in DT aliases */
323 id = of_alias_get_id(np, "serial");
327 if (of_device_is_compatible(np, "cavium,octeon-3860-uart")) {
328 p->serial_in = dw8250_serial_inq;
329 p->serial_out = dw8250_serial_outq;
330 p->flags = UPF_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE;
331 p->type = PORT_OCTEON;
332 data->usr_reg = 0x27;
333 data->skip_autocfg = true;
336 if (of_device_is_big_endian(p->dev->of_node)) {
337 p->iotype = UPIO_MEM32BE;
338 p->serial_in = dw8250_serial_in32be;
339 p->serial_out = dw8250_serial_out32be;
341 } else if (has_acpi_companion(p->dev)) {
342 const struct acpi_device_id *id;
344 id = acpi_match_device(p->dev->driver->acpi_match_table,
346 if (id && !strcmp(id->id, "APMC0D08")) {
347 p->iotype = UPIO_MEM32;
349 p->serial_in = dw8250_serial_in32;
350 data->uart_16550_compatible = true;
354 /* Platforms with iDMA */
355 if (platform_get_resource_byname(to_platform_device(p->dev),
356 IORESOURCE_MEM, "lpss_priv")) {
357 data->dma.rx_param = p->dev->parent;
358 data->dma.tx_param = p->dev->parent;
359 data->dma.fn = dw8250_idma_filter;
363 static void dw8250_setup_port(struct uart_port *p)
365 struct uart_8250_port *up = up_to_u8250p(p);
369 * If the Component Version Register returns zero, we know that
370 * ADDITIONAL_FEATURES are not enabled. No need to go any further.
372 if (p->iotype == UPIO_MEM32BE)
373 reg = ioread32be(p->membase + DW_UART_UCV);
375 reg = readl(p->membase + DW_UART_UCV);
379 dev_dbg(p->dev, "Designware UART version %c.%c%c\n",
380 (reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);
382 if (p->iotype == UPIO_MEM32BE)
383 reg = ioread32be(p->membase + DW_UART_CPR);
385 reg = readl(p->membase + DW_UART_CPR);
389 /* Select the type based on fifo */
390 if (reg & DW_UART_CPR_FIFO_MODE) {
391 p->type = PORT_16550A;
392 p->flags |= UPF_FIXED_TYPE;
393 p->fifosize = DW_UART_CPR_FIFO_SIZE(reg);
394 up->capabilities = UART_CAP_FIFO;
397 if (reg & DW_UART_CPR_AFCE_MODE)
398 up->capabilities |= UART_CAP_AFE;
400 if (reg & DW_UART_CPR_SIR_MODE)
401 up->capabilities |= UART_CAP_IRDA;
404 static int dw8250_probe(struct platform_device *pdev)
406 struct uart_8250_port uart = {};
407 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
408 int irq = platform_get_irq(pdev, 0);
409 struct uart_port *p = &uart.port;
410 struct device *dev = &pdev->dev;
411 struct dw8250_data *data;
416 dev_err(dev, "no registers defined\n");
421 if (irq != -EPROBE_DEFER)
422 dev_err(dev, "cannot get irq\n");
426 spin_lock_init(&p->lock);
427 p->mapbase = regs->start;
429 p->handle_irq = dw8250_handle_irq;
430 p->pm = dw8250_do_pm;
432 p->flags = UPF_SHARE_IRQ | UPF_FIXED_PORT;
434 p->iotype = UPIO_MEM;
435 p->serial_in = dw8250_serial_in;
436 p->serial_out = dw8250_serial_out;
437 p->set_ldisc = dw8250_set_ldisc;
438 p->set_termios = dw8250_set_termios;
440 p->membase = devm_ioremap(dev, regs->start, resource_size(regs));
444 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
448 data->dma.fn = dw8250_fallback_dma_filter;
449 data->usr_reg = DW_UART_USR;
450 p->private_data = data;
452 data->uart_16550_compatible = device_property_read_bool(dev,
453 "snps,uart-16550-compatible");
455 err = device_property_read_u32(dev, "reg-shift", &val);
459 err = device_property_read_u32(dev, "reg-io-width", &val);
460 if (!err && val == 4) {
461 p->iotype = UPIO_MEM32;
462 p->serial_in = dw8250_serial_in32;
463 p->serial_out = dw8250_serial_out32;
466 if (device_property_read_bool(dev, "dcd-override")) {
467 /* Always report DCD as active */
468 data->msr_mask_on |= UART_MSR_DCD;
469 data->msr_mask_off |= UART_MSR_DDCD;
472 if (device_property_read_bool(dev, "dsr-override")) {
473 /* Always report DSR as active */
474 data->msr_mask_on |= UART_MSR_DSR;
475 data->msr_mask_off |= UART_MSR_DDSR;
478 if (device_property_read_bool(dev, "cts-override")) {
479 /* Always report CTS as active */
480 data->msr_mask_on |= UART_MSR_CTS;
481 data->msr_mask_off |= UART_MSR_DCTS;
484 if (device_property_read_bool(dev, "ri-override")) {
485 /* Always report Ring indicator as inactive */
486 data->msr_mask_off |= UART_MSR_RI;
487 data->msr_mask_off |= UART_MSR_TERI;
490 /* Always ask for fixed clock rate from a property. */
491 device_property_read_u32(dev, "clock-frequency", &p->uartclk);
493 /* If there is separate baudclk, get the rate from it. */
494 data->clk = devm_clk_get(dev, "baudclk");
495 if (IS_ERR(data->clk) && PTR_ERR(data->clk) != -EPROBE_DEFER)
496 data->clk = devm_clk_get(dev, NULL);
497 if (IS_ERR(data->clk) && PTR_ERR(data->clk) == -EPROBE_DEFER)
498 return -EPROBE_DEFER;
499 if (!IS_ERR_OR_NULL(data->clk)) {
500 err = clk_prepare_enable(data->clk);
502 dev_warn(dev, "could not enable optional baudclk: %d\n",
505 p->uartclk = clk_get_rate(data->clk);
508 /* If no clock rate is defined, fail. */
510 dev_err(dev, "clock rate not defined\n");
514 data->pclk = devm_clk_get(dev, "apb_pclk");
515 if (IS_ERR(data->pclk) && PTR_ERR(data->pclk) == -EPROBE_DEFER) {
519 if (!IS_ERR(data->pclk)) {
520 err = clk_prepare_enable(data->pclk);
522 dev_err(dev, "could not enable apb_pclk\n");
527 data->rst = devm_reset_control_get_optional(dev, NULL);
528 if (IS_ERR(data->rst) && PTR_ERR(data->rst) == -EPROBE_DEFER) {
532 if (!IS_ERR(data->rst))
533 reset_control_deassert(data->rst);
535 dw8250_quirks(p, data);
537 /* If the Busy Functionality is not implemented, don't handle it */
538 if (data->uart_16550_compatible)
539 p->handle_irq = NULL;
541 if (!data->skip_autocfg)
542 dw8250_setup_port(p);
544 /* If we have a valid fifosize, try hooking up DMA */
546 data->dma.rxconf.src_maxburst = p->fifosize / 4;
547 data->dma.txconf.dst_maxburst = p->fifosize / 4;
548 uart.dma = &data->dma;
551 data->line = serial8250_register_8250_port(&uart);
552 if (data->line < 0) {
557 platform_set_drvdata(pdev, data);
559 pm_runtime_set_active(dev);
560 pm_runtime_enable(dev);
565 if (!IS_ERR(data->rst))
566 reset_control_assert(data->rst);
569 if (!IS_ERR(data->pclk))
570 clk_disable_unprepare(data->pclk);
573 if (!IS_ERR(data->clk))
574 clk_disable_unprepare(data->clk);
579 static int dw8250_remove(struct platform_device *pdev)
581 struct dw8250_data *data = platform_get_drvdata(pdev);
583 pm_runtime_get_sync(&pdev->dev);
585 serial8250_unregister_port(data->line);
587 if (!IS_ERR(data->rst))
588 reset_control_assert(data->rst);
590 if (!IS_ERR(data->pclk))
591 clk_disable_unprepare(data->pclk);
593 if (!IS_ERR(data->clk))
594 clk_disable_unprepare(data->clk);
596 pm_runtime_disable(&pdev->dev);
597 pm_runtime_put_noidle(&pdev->dev);
602 #ifdef CONFIG_PM_SLEEP
603 static int dw8250_suspend(struct device *dev)
605 struct dw8250_data *data = dev_get_drvdata(dev);
607 serial8250_suspend_port(data->line);
612 static int dw8250_resume(struct device *dev)
614 struct dw8250_data *data = dev_get_drvdata(dev);
616 serial8250_resume_port(data->line);
620 #endif /* CONFIG_PM_SLEEP */
623 static int dw8250_runtime_suspend(struct device *dev)
625 struct dw8250_data *data = dev_get_drvdata(dev);
627 if (!IS_ERR(data->clk))
628 clk_disable_unprepare(data->clk);
630 if (!IS_ERR(data->pclk))
631 clk_disable_unprepare(data->pclk);
636 static int dw8250_runtime_resume(struct device *dev)
638 struct dw8250_data *data = dev_get_drvdata(dev);
640 if (!IS_ERR(data->pclk))
641 clk_prepare_enable(data->pclk);
643 if (!IS_ERR(data->clk))
644 clk_prepare_enable(data->clk);
650 static const struct dev_pm_ops dw8250_pm_ops = {
651 SET_SYSTEM_SLEEP_PM_OPS(dw8250_suspend, dw8250_resume)
652 SET_RUNTIME_PM_OPS(dw8250_runtime_suspend, dw8250_runtime_resume, NULL)
655 static const struct of_device_id dw8250_of_match[] = {
656 { .compatible = "snps,dw-apb-uart" },
657 { .compatible = "cavium,octeon-3860-uart" },
660 MODULE_DEVICE_TABLE(of, dw8250_of_match);
662 static const struct acpi_device_id dw8250_acpi_match[] = {
675 MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match);
677 static struct platform_driver dw8250_platform_driver = {
679 .name = "dw-apb-uart",
680 .pm = &dw8250_pm_ops,
681 .of_match_table = dw8250_of_match,
682 .acpi_match_table = ACPI_PTR(dw8250_acpi_match),
684 .probe = dw8250_probe,
685 .remove = dw8250_remove,
688 module_platform_driver(dw8250_platform_driver);
690 MODULE_AUTHOR("Jamie Iles");
691 MODULE_LICENSE("GPL");
692 MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver");
693 MODULE_ALIAS("platform:dw-apb-uart");