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)
64 struct reset_control *rst;
65 struct uart_8250_dma dma;
67 unsigned int skip_autocfg:1;
68 unsigned int uart_16550_compatible:1;
71 #define BYT_PRV_CLK 0x800
72 #define BYT_PRV_CLK_EN (1 << 0)
73 #define BYT_PRV_CLK_M_VAL_SHIFT 1
74 #define BYT_PRV_CLK_N_VAL_SHIFT 16
75 #define BYT_PRV_CLK_UPDATE (1 << 31)
77 static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
79 struct dw8250_data *d = p->private_data;
81 /* Override any modem control signals if needed */
82 if (offset == UART_MSR) {
83 value |= d->msr_mask_on;
84 value &= ~d->msr_mask_off;
90 static void dw8250_force_idle(struct uart_port *p)
92 struct uart_8250_port *up = up_to_u8250p(p);
94 serial8250_clear_and_reinit_fifos(up);
95 (void)p->serial_in(p, UART_RX);
98 static void dw8250_serial_out(struct uart_port *p, int offset, int value)
100 writeb(value, p->membase + (offset << p->regshift));
102 /* Make sure LCR write wasn't ignored */
103 if (offset == UART_LCR) {
106 unsigned int lcr = p->serial_in(p, UART_LCR);
107 if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
109 dw8250_force_idle(p);
110 writeb(value, p->membase + (UART_LCR << p->regshift));
113 * FIXME: this deadlocks if port->lock is already held
114 * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
119 static unsigned int dw8250_serial_in(struct uart_port *p, int offset)
121 unsigned int value = readb(p->membase + (offset << p->regshift));
123 return dw8250_modify_msr(p, offset, value);
127 static unsigned int dw8250_serial_inq(struct uart_port *p, int offset)
131 value = (u8)__raw_readq(p->membase + (offset << p->regshift));
133 return dw8250_modify_msr(p, offset, value);
136 static void dw8250_serial_outq(struct uart_port *p, int offset, int value)
139 __raw_writeq(value, p->membase + (offset << p->regshift));
140 /* Read back to ensure register write ordering. */
141 __raw_readq(p->membase + (UART_LCR << p->regshift));
143 /* Make sure LCR write wasn't ignored */
144 if (offset == UART_LCR) {
147 unsigned int lcr = p->serial_in(p, UART_LCR);
148 if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
150 dw8250_force_idle(p);
151 __raw_writeq(value & 0xff,
152 p->membase + (UART_LCR << p->regshift));
155 * FIXME: this deadlocks if port->lock is already held
156 * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
160 #endif /* CONFIG_64BIT */
162 static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
164 writel(value, p->membase + (offset << p->regshift));
166 /* Make sure LCR write wasn't ignored */
167 if (offset == UART_LCR) {
170 unsigned int lcr = p->serial_in(p, UART_LCR);
171 if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
173 dw8250_force_idle(p);
174 writel(value, p->membase + (UART_LCR << p->regshift));
177 * FIXME: this deadlocks if port->lock is already held
178 * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
183 static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
185 unsigned int value = readl(p->membase + (offset << p->regshift));
187 return dw8250_modify_msr(p, offset, value);
190 static int dw8250_handle_irq(struct uart_port *p)
192 struct dw8250_data *d = p->private_data;
193 unsigned int iir = p->serial_in(p, UART_IIR);
195 if (serial8250_handle_irq(p, iir)) {
197 } else if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
199 (void)p->serial_in(p, d->usr_reg);
208 dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
211 pm_runtime_get_sync(port->dev);
213 serial8250_do_pm(port, state, old);
216 pm_runtime_put_sync_suspend(port->dev);
219 static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
220 struct ktermios *old)
222 unsigned int baud = tty_termios_baud_rate(termios);
223 struct dw8250_data *d = p->private_data;
227 if (IS_ERR(d->clk) || !old)
230 /* Not requesting clock rates below 1.8432Mhz */
234 clk_disable_unprepare(d->clk);
235 rate = clk_round_rate(d->clk, baud * 16);
236 ret = clk_set_rate(d->clk, rate);
237 clk_prepare_enable(d->clk);
242 p->status &= ~UPSTAT_AUTOCTS;
243 if (termios->c_cflag & CRTSCTS)
244 p->status |= UPSTAT_AUTOCTS;
247 serial8250_do_set_termios(p, termios, old);
251 * dw8250_fallback_dma_filter will prevent the UART from getting just any free
252 * channel on platforms that have DMA engines, but don't have any channels
253 * assigned to the UART.
255 * REVISIT: This is a work around for limitation in the DMA Engine API. Once the
256 * core problem is fixed, this function is no longer needed.
258 static bool dw8250_fallback_dma_filter(struct dma_chan *chan, void *param)
263 static void dw8250_setup_port(struct uart_8250_port *up)
265 struct uart_port *p = &up->port;
266 u32 reg = readl(p->membase + DW_UART_UCV);
269 * If the Component Version Register returns zero, we know that
270 * ADDITIONAL_FEATURES are not enabled. No need to go any further.
275 dev_dbg_ratelimited(p->dev, "Designware UART version %c.%c%c\n",
276 (reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);
278 reg = readl(p->membase + DW_UART_CPR);
282 /* Select the type based on fifo */
283 if (reg & DW_UART_CPR_FIFO_MODE) {
284 p->type = PORT_16550A;
285 p->flags |= UPF_FIXED_TYPE;
286 p->fifosize = DW_UART_CPR_FIFO_SIZE(reg);
287 up->tx_loadsz = p->fifosize;
288 up->capabilities = UART_CAP_FIFO;
291 if (reg & DW_UART_CPR_AFCE_MODE)
292 up->capabilities |= UART_CAP_AFE;
295 static bool dw8250_idma_filter(struct dma_chan *chan, void *param)
297 struct device *dev = param;
299 if (dev != chan->device->dev->parent)
305 static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data)
307 if (p->dev->of_node) {
308 struct device_node *np = p->dev->of_node;
311 /* get index of serial line, if found in DT aliases */
312 id = of_alias_get_id(np, "serial");
316 if (of_device_is_compatible(np, "cavium,octeon-3860-uart")) {
317 p->serial_in = dw8250_serial_inq;
318 p->serial_out = dw8250_serial_outq;
319 p->flags = UPF_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE;
320 p->type = PORT_OCTEON;
321 data->usr_reg = 0x27;
322 data->skip_autocfg = true;
325 } else if (has_acpi_companion(p->dev)) {
326 p->iotype = UPIO_MEM32;
328 p->serial_in = dw8250_serial_in32;
329 p->set_termios = dw8250_set_termios;
330 /* So far none of there implement the Busy Functionality */
331 data->uart_16550_compatible = true;
334 /* Platforms with iDMA */
335 if (platform_get_resource_byname(to_platform_device(p->dev),
336 IORESOURCE_MEM, "lpss_priv")) {
337 p->set_termios = dw8250_set_termios;
338 data->dma.rx_param = p->dev->parent;
339 data->dma.tx_param = p->dev->parent;
340 data->dma.fn = dw8250_idma_filter;
344 static int dw8250_probe(struct platform_device *pdev)
346 struct uart_8250_port uart = {};
347 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
348 int irq = platform_get_irq(pdev, 0);
349 struct uart_port *p = &uart.port;
350 struct dw8250_data *data;
355 dev_err(&pdev->dev, "no registers defined\n");
360 if (irq != -EPROBE_DEFER)
361 dev_err(&pdev->dev, "cannot get irq\n");
365 spin_lock_init(&p->lock);
366 p->mapbase = regs->start;
368 p->handle_irq = dw8250_handle_irq;
369 p->pm = dw8250_do_pm;
371 p->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
373 p->iotype = UPIO_MEM;
374 p->serial_in = dw8250_serial_in;
375 p->serial_out = dw8250_serial_out;
377 p->membase = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
381 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
385 data->dma.fn = dw8250_fallback_dma_filter;
386 data->usr_reg = DW_UART_USR;
387 p->private_data = data;
389 data->uart_16550_compatible = device_property_read_bool(p->dev,
390 "snps,uart-16550-compatible");
392 err = device_property_read_u32(p->dev, "reg-shift", &val);
396 err = device_property_read_u32(p->dev, "reg-io-width", &val);
397 if (!err && val == 4) {
398 p->iotype = UPIO_MEM32;
399 p->serial_in = dw8250_serial_in32;
400 p->serial_out = dw8250_serial_out32;
403 if (device_property_read_bool(p->dev, "dcd-override")) {
404 /* Always report DCD as active */
405 data->msr_mask_on |= UART_MSR_DCD;
406 data->msr_mask_off |= UART_MSR_DDCD;
409 if (device_property_read_bool(p->dev, "dsr-override")) {
410 /* Always report DSR as active */
411 data->msr_mask_on |= UART_MSR_DSR;
412 data->msr_mask_off |= UART_MSR_DDSR;
415 if (device_property_read_bool(p->dev, "cts-override")) {
416 /* Always report CTS as active */
417 data->msr_mask_on |= UART_MSR_CTS;
418 data->msr_mask_off |= UART_MSR_DCTS;
421 if (device_property_read_bool(p->dev, "ri-override")) {
422 /* Always report Ring indicator as inactive */
423 data->msr_mask_off |= UART_MSR_RI;
424 data->msr_mask_off |= UART_MSR_TERI;
427 /* Always ask for fixed clock rate from a property. */
428 device_property_read_u32(p->dev, "clock-frequency", &p->uartclk);
430 /* If there is separate baudclk, get the rate from it. */
431 data->clk = devm_clk_get(&pdev->dev, "baudclk");
432 if (IS_ERR(data->clk) && PTR_ERR(data->clk) != -EPROBE_DEFER)
433 data->clk = devm_clk_get(&pdev->dev, NULL);
434 if (IS_ERR(data->clk) && PTR_ERR(data->clk) == -EPROBE_DEFER)
435 return -EPROBE_DEFER;
436 if (!IS_ERR_OR_NULL(data->clk)) {
437 err = clk_prepare_enable(data->clk);
439 dev_warn(&pdev->dev, "could not enable optional baudclk: %d\n",
442 p->uartclk = clk_get_rate(data->clk);
445 /* If no clock rate is defined, fail. */
447 dev_err(&pdev->dev, "clock rate not defined\n");
451 data->pclk = devm_clk_get(&pdev->dev, "apb_pclk");
452 if (IS_ERR(data->clk) && PTR_ERR(data->clk) == -EPROBE_DEFER) {
456 if (!IS_ERR(data->pclk)) {
457 err = clk_prepare_enable(data->pclk);
459 dev_err(&pdev->dev, "could not enable apb_pclk\n");
464 data->rst = devm_reset_control_get_optional(&pdev->dev, NULL);
465 if (IS_ERR(data->rst) && PTR_ERR(data->rst) == -EPROBE_DEFER) {
469 if (!IS_ERR(data->rst))
470 reset_control_deassert(data->rst);
472 dw8250_quirks(p, data);
474 /* If the Busy Functionality is not implemented, don't handle it */
475 if (data->uart_16550_compatible) {
476 p->serial_out = NULL;
477 p->handle_irq = NULL;
480 if (!data->skip_autocfg)
481 dw8250_setup_port(&uart);
483 /* If we have a valid fifosize, try hooking up DMA */
485 data->dma.rxconf.src_maxburst = p->fifosize / 4;
486 data->dma.txconf.dst_maxburst = p->fifosize / 4;
487 uart.dma = &data->dma;
490 data->line = serial8250_register_8250_port(&uart);
491 if (data->line < 0) {
496 platform_set_drvdata(pdev, data);
498 pm_runtime_set_active(&pdev->dev);
499 pm_runtime_enable(&pdev->dev);
504 if (!IS_ERR(data->rst))
505 reset_control_assert(data->rst);
508 if (!IS_ERR(data->pclk))
509 clk_disable_unprepare(data->pclk);
512 if (!IS_ERR(data->clk))
513 clk_disable_unprepare(data->clk);
518 static int dw8250_remove(struct platform_device *pdev)
520 struct dw8250_data *data = platform_get_drvdata(pdev);
522 pm_runtime_get_sync(&pdev->dev);
524 serial8250_unregister_port(data->line);
526 if (!IS_ERR(data->rst))
527 reset_control_assert(data->rst);
529 if (!IS_ERR(data->pclk))
530 clk_disable_unprepare(data->pclk);
532 if (!IS_ERR(data->clk))
533 clk_disable_unprepare(data->clk);
535 pm_runtime_disable(&pdev->dev);
536 pm_runtime_put_noidle(&pdev->dev);
541 #ifdef CONFIG_PM_SLEEP
542 static int dw8250_suspend(struct device *dev)
544 struct dw8250_data *data = dev_get_drvdata(dev);
546 serial8250_suspend_port(data->line);
551 static int dw8250_resume(struct device *dev)
553 struct dw8250_data *data = dev_get_drvdata(dev);
555 serial8250_resume_port(data->line);
559 #endif /* CONFIG_PM_SLEEP */
562 static int dw8250_runtime_suspend(struct device *dev)
564 struct dw8250_data *data = dev_get_drvdata(dev);
566 if (!IS_ERR(data->clk))
567 clk_disable_unprepare(data->clk);
569 if (!IS_ERR(data->pclk))
570 clk_disable_unprepare(data->pclk);
575 static int dw8250_runtime_resume(struct device *dev)
577 struct dw8250_data *data = dev_get_drvdata(dev);
579 if (!IS_ERR(data->pclk))
580 clk_prepare_enable(data->pclk);
582 if (!IS_ERR(data->clk))
583 clk_prepare_enable(data->clk);
589 static const struct dev_pm_ops dw8250_pm_ops = {
590 SET_SYSTEM_SLEEP_PM_OPS(dw8250_suspend, dw8250_resume)
591 SET_RUNTIME_PM_OPS(dw8250_runtime_suspend, dw8250_runtime_resume, NULL)
594 static const struct of_device_id dw8250_of_match[] = {
595 { .compatible = "snps,dw-apb-uart" },
596 { .compatible = "cavium,octeon-3860-uart" },
599 MODULE_DEVICE_TABLE(of, dw8250_of_match);
601 static const struct acpi_device_id dw8250_acpi_match[] = {
612 MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match);
614 static struct platform_driver dw8250_platform_driver = {
616 .name = "dw-apb-uart",
617 .pm = &dw8250_pm_ops,
618 .of_match_table = dw8250_of_match,
619 .acpi_match_table = ACPI_PTR(dw8250_acpi_match),
621 .probe = dw8250_probe,
622 .remove = dw8250_remove,
625 module_platform_driver(dw8250_platform_driver);
627 MODULE_AUTHOR("Jamie Iles");
628 MODULE_LICENSE("GPL");
629 MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver");
630 MODULE_ALIAS("platform:dw-apb-uart");