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>
17 #include <linux/init.h>
19 #include <linux/module.h>
20 #include <linux/serial_8250.h>
21 #include <linux/serial_core.h>
22 #include <linux/serial_reg.h>
24 #include <linux/of_irq.h>
25 #include <linux/of_platform.h>
26 #include <linux/platform_device.h>
27 #include <linux/slab.h>
28 #include <linux/acpi.h>
29 #include <linux/clk.h>
30 #include <linux/pm_runtime.h>
32 #include <asm/byteorder.h>
36 /* Offsets for the DesignWare specific registers */
37 #define DW_UART_USR 0x1f /* UART Status Register */
38 #define DW_UART_CPR 0xf4 /* Component Parameter Register */
39 #define DW_UART_UCV 0xf8 /* UART Component Version */
41 /* Component Parameter Register bits */
42 #define DW_UART_CPR_ABP_DATA_WIDTH (3 << 0)
43 #define DW_UART_CPR_AFCE_MODE (1 << 4)
44 #define DW_UART_CPR_THRE_MODE (1 << 5)
45 #define DW_UART_CPR_SIR_MODE (1 << 6)
46 #define DW_UART_CPR_SIR_LP_MODE (1 << 7)
47 #define DW_UART_CPR_ADDITIONAL_FEATURES (1 << 8)
48 #define DW_UART_CPR_FIFO_ACCESS (1 << 9)
49 #define DW_UART_CPR_FIFO_STAT (1 << 10)
50 #define DW_UART_CPR_SHADOW (1 << 11)
51 #define DW_UART_CPR_ENCODED_PARMS (1 << 12)
52 #define DW_UART_CPR_DMA_EXTRA (1 << 13)
53 #define DW_UART_CPR_FIFO_MODE (0xff << 16)
54 /* Helper for fifo size calculation */
55 #define DW_UART_CPR_FIFO_SIZE(a) (((a >> 16) & 0xff) * 16)
66 static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
68 struct dw8250_data *d = p->private_data;
70 /* If reading MSR, report CTS asserted when auto-CTS/RTS enabled */
71 if (offset == UART_MSR && d->last_mcr & UART_MCR_AFE) {
72 value |= UART_MSR_CTS;
73 value &= ~UART_MSR_DCTS;
79 static void dw8250_serial_out(struct uart_port *p, int offset, int value)
81 struct dw8250_data *d = p->private_data;
83 if (offset == UART_LCR)
86 if (offset == UART_MCR)
89 writeb(value, p->membase + (offset << p->regshift));
92 static unsigned int dw8250_serial_in(struct uart_port *p, int offset)
94 unsigned int value = readb(p->membase + (offset << p->regshift));
96 return dw8250_modify_msr(p, offset, value);
99 /* Read Back (rb) version to ensure register access ording. */
100 static void dw8250_serial_out_rb(struct uart_port *p, int offset, int value)
102 dw8250_serial_out(p, offset, value);
103 dw8250_serial_in(p, UART_LCR);
106 static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
108 struct dw8250_data *d = p->private_data;
110 if (offset == UART_LCR)
113 if (offset == UART_MCR)
116 writel(value, p->membase + (offset << p->regshift));
119 static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
121 unsigned int value = readl(p->membase + (offset << p->regshift));
123 return dw8250_modify_msr(p, offset, value);
126 static int dw8250_handle_irq(struct uart_port *p)
128 struct dw8250_data *d = p->private_data;
129 unsigned int iir = p->serial_in(p, UART_IIR);
131 if (serial8250_handle_irq(p, iir)) {
133 } else if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
134 /* Clear the USR and write the LCR again. */
135 (void)p->serial_in(p, d->usr_reg);
136 p->serial_out(p, UART_LCR, d->last_lcr);
145 dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
148 pm_runtime_get_sync(port->dev);
150 serial8250_do_pm(port, state, old);
153 pm_runtime_put_sync_suspend(port->dev);
156 static void dw8250_setup_port(struct uart_8250_port *up)
158 struct uart_port *p = &up->port;
159 u32 reg = readl(p->membase + DW_UART_UCV);
162 * If the Component Version Register returns zero, we know that
163 * ADDITIONAL_FEATURES are not enabled. No need to go any further.
168 dev_dbg_ratelimited(p->dev, "Designware UART version %c.%c%c\n",
169 (reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);
171 reg = readl(p->membase + DW_UART_CPR);
175 /* Select the type based on fifo */
176 if (reg & DW_UART_CPR_FIFO_MODE) {
177 p->type = PORT_16550A;
178 p->flags |= UPF_FIXED_TYPE;
179 p->fifosize = DW_UART_CPR_FIFO_SIZE(reg);
180 up->tx_loadsz = p->fifosize;
181 up->capabilities = UART_CAP_FIFO;
184 if (reg & DW_UART_CPR_AFCE_MODE)
185 up->capabilities |= UART_CAP_AFE;
188 static int dw8250_probe_of(struct uart_port *p,
189 struct dw8250_data *data)
191 struct device_node *np = p->dev->of_node;
195 if (of_device_is_compatible(np, "cavium,octeon-3860-uart")) {
198 * Low order bits of these 64-bit registers, when
199 * accessed as a byte, are 7 bytes further down in the
200 * address space in big endian mode.
204 p->serial_out = dw8250_serial_out_rb;
205 p->flags = ASYNC_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE;
206 p->type = PORT_OCTEON;
207 data->usr_reg = 0x27;
209 } else if (!of_property_read_u32(np, "reg-io-width", &val)) {
214 p->iotype = UPIO_MEM32;
215 p->serial_in = dw8250_serial_in32;
216 p->serial_out = dw8250_serial_out32;
219 dev_err(p->dev, "unsupported reg-io-width (%u)\n", val);
224 dw8250_setup_port(container_of(p, struct uart_8250_port, port));
226 if (!of_property_read_u32(np, "reg-shift", &val))
229 /* clock got configured through clk api, all done */
233 /* try to find out clock frequency from DT as fallback */
234 if (of_property_read_u32(np, "clock-frequency", &val)) {
235 dev_err(p->dev, "clk or clock-frequency not defined\n");
244 static int dw8250_probe_acpi(struct uart_8250_port *up)
246 const struct acpi_device_id *id;
247 struct uart_port *p = &up->port;
249 dw8250_setup_port(up);
251 id = acpi_match_device(p->dev->driver->acpi_match_table, p->dev);
255 p->iotype = UPIO_MEM32;
256 p->serial_in = dw8250_serial_in32;
257 p->serial_out = dw8250_serial_out32;
261 p->uartclk = (unsigned int)id->driver_data;
263 up->dma = devm_kzalloc(p->dev, sizeof(*up->dma), GFP_KERNEL);
267 up->dma->rxconf.src_maxburst = p->fifosize / 4;
268 up->dma->txconf.dst_maxburst = p->fifosize / 4;
273 static inline int dw8250_probe_acpi(struct uart_8250_port *up)
277 #endif /* CONFIG_ACPI */
279 static int dw8250_probe(struct platform_device *pdev)
281 struct uart_8250_port uart = {};
282 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
283 struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
284 struct dw8250_data *data;
288 dev_err(&pdev->dev, "no registers/irq defined\n");
292 spin_lock_init(&uart.port.lock);
293 uart.port.mapbase = regs->start;
294 uart.port.irq = irq->start;
295 uart.port.handle_irq = dw8250_handle_irq;
296 uart.port.pm = dw8250_do_pm;
297 uart.port.type = PORT_8250;
298 uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
299 uart.port.dev = &pdev->dev;
301 uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
302 resource_size(regs));
303 if (!uart.port.membase)
306 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
310 data->usr_reg = DW_UART_USR;
311 data->clk = devm_clk_get(&pdev->dev, NULL);
312 if (!IS_ERR(data->clk)) {
313 clk_prepare_enable(data->clk);
314 uart.port.uartclk = clk_get_rate(data->clk);
317 uart.port.iotype = UPIO_MEM;
318 uart.port.serial_in = dw8250_serial_in;
319 uart.port.serial_out = dw8250_serial_out;
320 uart.port.private_data = data;
322 if (pdev->dev.of_node) {
323 err = dw8250_probe_of(&uart.port, data);
326 } else if (ACPI_HANDLE(&pdev->dev)) {
327 err = dw8250_probe_acpi(&uart);
334 data->line = serial8250_register_8250_port(&uart);
338 platform_set_drvdata(pdev, data);
340 pm_runtime_set_active(&pdev->dev);
341 pm_runtime_enable(&pdev->dev);
346 static int dw8250_remove(struct platform_device *pdev)
348 struct dw8250_data *data = platform_get_drvdata(pdev);
350 pm_runtime_get_sync(&pdev->dev);
352 serial8250_unregister_port(data->line);
354 if (!IS_ERR(data->clk))
355 clk_disable_unprepare(data->clk);
357 pm_runtime_disable(&pdev->dev);
358 pm_runtime_put_noidle(&pdev->dev);
364 static int dw8250_suspend(struct device *dev)
366 struct dw8250_data *data = dev_get_drvdata(dev);
368 serial8250_suspend_port(data->line);
373 static int dw8250_resume(struct device *dev)
375 struct dw8250_data *data = dev_get_drvdata(dev);
377 serial8250_resume_port(data->line);
381 #endif /* CONFIG_PM */
383 #ifdef CONFIG_PM_RUNTIME
384 static int dw8250_runtime_suspend(struct device *dev)
386 struct dw8250_data *data = dev_get_drvdata(dev);
388 if (!IS_ERR(data->clk))
389 clk_disable_unprepare(data->clk);
394 static int dw8250_runtime_resume(struct device *dev)
396 struct dw8250_data *data = dev_get_drvdata(dev);
398 if (!IS_ERR(data->clk))
399 clk_prepare_enable(data->clk);
405 static const struct dev_pm_ops dw8250_pm_ops = {
406 SET_SYSTEM_SLEEP_PM_OPS(dw8250_suspend, dw8250_resume)
407 SET_RUNTIME_PM_OPS(dw8250_runtime_suspend, dw8250_runtime_resume, NULL)
410 static const struct of_device_id dw8250_of_match[] = {
411 { .compatible = "snps,dw-apb-uart" },
412 { .compatible = "cavium,octeon-3860-uart" },
415 MODULE_DEVICE_TABLE(of, dw8250_of_match);
417 static const struct acpi_device_id dw8250_acpi_match[] = {
423 MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match);
425 static struct platform_driver dw8250_platform_driver = {
427 .name = "dw-apb-uart",
428 .owner = THIS_MODULE,
429 .pm = &dw8250_pm_ops,
430 .of_match_table = dw8250_of_match,
431 .acpi_match_table = ACPI_PTR(dw8250_acpi_match),
433 .probe = dw8250_probe,
434 .remove = dw8250_remove,
437 module_platform_driver(dw8250_platform_driver);
439 MODULE_AUTHOR("Jamie Iles");
440 MODULE_LICENSE("GPL");
441 MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver");