1 // SPDX-License-Identifier: GPL-2.0
3 * 8250_lpss.c - Driver for UART on Intel Braswell and various other Intel SoCs
5 * Copyright (C) 2016 Intel Corporation
6 * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
9 #include <linux/bitops.h>
10 #include <linux/module.h>
11 #include <linux/pci.h>
12 #include <linux/rational.h>
14 #include <linux/dmaengine.h>
15 #include <linux/dma/dw.h>
17 #include "8250_dwlib.h"
19 #define PCI_DEVICE_ID_INTEL_QRK_UARTx 0x0936
21 #define PCI_DEVICE_ID_INTEL_BYT_UART1 0x0f0a
22 #define PCI_DEVICE_ID_INTEL_BYT_UART2 0x0f0c
24 #define PCI_DEVICE_ID_INTEL_BSW_UART1 0x228a
25 #define PCI_DEVICE_ID_INTEL_BSW_UART2 0x228c
27 #define PCI_DEVICE_ID_INTEL_EHL_UART0 0x4b96
28 #define PCI_DEVICE_ID_INTEL_EHL_UART1 0x4b97
29 #define PCI_DEVICE_ID_INTEL_EHL_UART2 0x4b98
30 #define PCI_DEVICE_ID_INTEL_EHL_UART3 0x4b99
31 #define PCI_DEVICE_ID_INTEL_EHL_UART4 0x4b9a
32 #define PCI_DEVICE_ID_INTEL_EHL_UART5 0x4b9b
34 #define PCI_DEVICE_ID_INTEL_BDW_UART1 0x9ce3
35 #define PCI_DEVICE_ID_INTEL_BDW_UART2 0x9ce4
37 /* Intel LPSS specific registers */
39 #define BYT_PRV_CLK 0x800
40 #define BYT_PRV_CLK_EN BIT(0)
41 #define BYT_PRV_CLK_M_VAL_SHIFT 1
42 #define BYT_PRV_CLK_N_VAL_SHIFT 16
43 #define BYT_PRV_CLK_UPDATE BIT(31)
45 #define BYT_TX_OVF_INT 0x820
46 #define BYT_TX_OVF_INT_MASK BIT(1)
50 struct lpss8250_board {
52 unsigned int base_baud;
53 int (*setup)(struct lpss8250 *, struct uart_port *p);
54 void (*exit)(struct lpss8250 *);
58 struct dw8250_port_data data;
59 struct lpss8250_board *board;
62 struct dw_dma_chip dma_chip;
63 struct dw_dma_slave dma_param;
67 static inline struct lpss8250 *to_lpss8250(struct dw8250_port_data *data)
69 return container_of(data, struct lpss8250, data);
72 static void byt_set_termios(struct uart_port *p, struct ktermios *termios,
73 const struct ktermios *old)
75 unsigned int baud = tty_termios_baud_rate(termios);
76 struct lpss8250 *lpss = to_lpss8250(p->private_data);
77 unsigned long fref = lpss->board->freq, fuart = baud * 16;
78 unsigned long w = BIT(15) - 1;
82 /* Gracefully handle the B0 case: fall back to B9600 */
83 fuart = fuart ? fuart : 9600 * 16;
85 /* Get Fuart closer to Fref */
86 fuart *= rounddown_pow_of_two(fref / fuart);
89 * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
90 * dividers must be adjusted.
92 * uartclk = (m / n) * 100 MHz, where m <= n
94 rational_best_approximation(fuart, fref, w, w, &m, &n);
98 reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT);
99 writel(reg, p->membase + BYT_PRV_CLK);
100 reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE;
101 writel(reg, p->membase + BYT_PRV_CLK);
103 dw8250_do_set_termios(p, termios, old);
106 static unsigned int byt_get_mctrl(struct uart_port *port)
108 unsigned int ret = serial8250_do_get_mctrl(port);
110 /* Force DCD and DSR signals to permanently be reported as active */
111 ret |= TIOCM_CAR | TIOCM_DSR;
116 static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
118 struct dw_dma_slave *param = &lpss->dma_param;
119 struct pci_dev *pdev = to_pci_dev(port->dev);
120 struct pci_dev *dma_dev;
122 switch (pdev->device) {
123 case PCI_DEVICE_ID_INTEL_BYT_UART1:
124 case PCI_DEVICE_ID_INTEL_BSW_UART1:
125 case PCI_DEVICE_ID_INTEL_BDW_UART1:
129 case PCI_DEVICE_ID_INTEL_BYT_UART2:
130 case PCI_DEVICE_ID_INTEL_BSW_UART2:
131 case PCI_DEVICE_ID_INTEL_BDW_UART2:
139 dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));
141 param->dma_dev = &dma_dev->dev;
145 lpss->dma_maxburst = 16;
147 port->set_termios = byt_set_termios;
148 port->get_mctrl = byt_get_mctrl;
150 /* Disable TX counter interrupts */
151 writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT);
156 static void byt_serial_exit(struct lpss8250 *lpss)
158 struct dw_dma_slave *param = &lpss->dma_param;
160 /* Paired with pci_get_slot() in the byt_serial_setup() above */
161 put_device(param->dma_dev);
164 static int ehl_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
166 struct uart_8250_dma *dma = &lpss->data.dma;
167 struct uart_8250_port *up = up_to_u8250p(port);
170 * This simply makes the checks in the 8250_port to try the DMA
171 * channel request which in turn uses the magic of ACPI tables
172 * parsing (see drivers/dma/acpi-dma.c for the details) and
173 * matching with the registered General Purpose DMA controllers.
177 lpss->dma_maxburst = 16;
179 port->set_termios = dw8250_do_set_termios;
184 static void ehl_serial_exit(struct lpss8250 *lpss)
186 struct uart_8250_port *up = serial8250_get_port(lpss->data.line);
191 #ifdef CONFIG_SERIAL_8250_DMA
192 static const struct dw_dma_platform_data qrk_serial_dma_pdata = {
194 .chan_allocation_order = CHAN_ALLOCATION_ASCENDING,
195 .chan_priority = CHAN_PRIORITY_ASCENDING,
202 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
204 struct uart_8250_dma *dma = &lpss->data.dma;
205 struct dw_dma_chip *chip = &lpss->dma_chip;
206 struct dw_dma_slave *param = &lpss->dma_param;
207 struct pci_dev *pdev = to_pci_dev(port->dev);
210 chip->pdata = &qrk_serial_dma_pdata;
211 chip->dev = &pdev->dev;
212 chip->id = pdev->devfn;
213 chip->irq = pci_irq_vector(pdev, 0);
214 chip->regs = pci_ioremap_bar(pdev, 1);
218 /* Falling back to PIO mode if DMA probing fails */
219 ret = dw_dma_probe(chip);
223 pci_try_set_mwi(pdev);
225 /* Special DMA address for UART */
226 dma->rx_dma_addr = 0xfffff000;
227 dma->tx_dma_addr = 0xfffff000;
229 param->dma_dev = &pdev->dev;
232 param->hs_polarity = true;
234 lpss->dma_maxburst = 8;
237 static void qrk_serial_exit_dma(struct lpss8250 *lpss)
239 struct dw_dma_chip *chip = &lpss->dma_chip;
240 struct dw_dma_slave *param = &lpss->dma_param;
247 pci_iounmap(to_pci_dev(chip->dev), chip->regs);
249 #else /* CONFIG_SERIAL_8250_DMA */
250 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}
251 static void qrk_serial_exit_dma(struct lpss8250 *lpss) {}
252 #endif /* !CONFIG_SERIAL_8250_DMA */
254 static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
256 qrk_serial_setup_dma(lpss, port);
260 static void qrk_serial_exit(struct lpss8250 *lpss)
262 qrk_serial_exit_dma(lpss);
265 static bool lpss8250_dma_filter(struct dma_chan *chan, void *param)
267 struct dw_dma_slave *dws = param;
269 if (dws->dma_dev != chan->device->dev)
276 static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port)
278 struct uart_8250_dma *dma = &lpss->data.dma;
279 struct dw_dma_slave *rx_param, *tx_param;
280 struct device *dev = port->port.dev;
282 if (!lpss->dma_param.dma_dev) {
285 goto out_configuration_only;
290 rx_param = devm_kmemdup(dev, &lpss->dma_param, sizeof(*rx_param), GFP_KERNEL);
294 tx_param = devm_kmemdup(dev, &lpss->dma_param, sizeof(*tx_param), GFP_KERNEL);
298 dma->fn = lpss8250_dma_filter;
299 dma->rx_param = rx_param;
300 dma->tx_param = tx_param;
304 out_configuration_only:
305 dma->rxconf.src_maxburst = lpss->dma_maxburst;
306 dma->txconf.dst_maxburst = lpss->dma_maxburst;
311 static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
313 struct uart_8250_port uart;
314 struct lpss8250 *lpss;
317 ret = pcim_enable_device(pdev);
321 pci_set_master(pdev);
323 lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL);
327 ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
331 lpss->board = (struct lpss8250_board *)id->driver_data;
333 memset(&uart, 0, sizeof(struct uart_8250_port));
335 uart.port.dev = &pdev->dev;
336 uart.port.irq = pci_irq_vector(pdev, 0);
337 uart.port.private_data = &lpss->data;
338 uart.port.type = PORT_16550A;
339 uart.port.iotype = UPIO_MEM32;
340 uart.port.regshift = 2;
341 uart.port.uartclk = lpss->board->base_baud * 16;
342 uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
343 uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
344 uart.port.mapbase = pci_resource_start(pdev, 0);
345 uart.port.membase = pcim_iomap(pdev, 0, 0);
346 if (!uart.port.membase)
349 ret = lpss->board->setup(lpss, &uart.port);
353 dw8250_setup_port(&uart.port);
355 ret = lpss8250_dma_setup(lpss, &uart);
359 ret = serial8250_register_8250_port(&uart);
363 lpss->data.line = ret;
365 pci_set_drvdata(pdev, lpss);
369 lpss->board->exit(lpss);
370 pci_free_irq_vectors(pdev);
374 static void lpss8250_remove(struct pci_dev *pdev)
376 struct lpss8250 *lpss = pci_get_drvdata(pdev);
378 serial8250_unregister_port(lpss->data.line);
380 lpss->board->exit(lpss);
381 pci_free_irq_vectors(pdev);
384 static const struct lpss8250_board byt_board = {
386 .base_baud = 2764800,
387 .setup = byt_serial_setup,
388 .exit = byt_serial_exit,
391 static const struct lpss8250_board ehl_board = {
393 .base_baud = 12500000,
394 .setup = ehl_serial_setup,
395 .exit = ehl_serial_exit,
398 static const struct lpss8250_board qrk_board = {
400 .base_baud = 2764800,
401 .setup = qrk_serial_setup,
402 .exit = qrk_serial_exit,
405 static const struct pci_device_id pci_ids[] = {
406 { PCI_DEVICE_DATA(INTEL, QRK_UARTx, &qrk_board) },
407 { PCI_DEVICE_DATA(INTEL, EHL_UART0, &ehl_board) },
408 { PCI_DEVICE_DATA(INTEL, EHL_UART1, &ehl_board) },
409 { PCI_DEVICE_DATA(INTEL, EHL_UART2, &ehl_board) },
410 { PCI_DEVICE_DATA(INTEL, EHL_UART3, &ehl_board) },
411 { PCI_DEVICE_DATA(INTEL, EHL_UART4, &ehl_board) },
412 { PCI_DEVICE_DATA(INTEL, EHL_UART5, &ehl_board) },
413 { PCI_DEVICE_DATA(INTEL, BYT_UART1, &byt_board) },
414 { PCI_DEVICE_DATA(INTEL, BYT_UART2, &byt_board) },
415 { PCI_DEVICE_DATA(INTEL, BSW_UART1, &byt_board) },
416 { PCI_DEVICE_DATA(INTEL, BSW_UART2, &byt_board) },
417 { PCI_DEVICE_DATA(INTEL, BDW_UART1, &byt_board) },
418 { PCI_DEVICE_DATA(INTEL, BDW_UART2, &byt_board) },
421 MODULE_DEVICE_TABLE(pci, pci_ids);
423 static struct pci_driver lpss8250_pci_driver = {
426 .probe = lpss8250_probe,
427 .remove = lpss8250_remove,
430 module_pci_driver(lpss8250_pci_driver);
432 MODULE_AUTHOR("Intel Corporation");
433 MODULE_LICENSE("GPL v2");
434 MODULE_DESCRIPTION("Intel LPSS UART driver");