2 * 8250_lpss.c - Driver for UART on Intel Braswell and various other Intel SoCs
4 * Copyright (C) 2016 Intel Corporation
5 * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/bitops.h>
13 #include <linux/module.h>
14 #include <linux/pci.h>
15 #include <linux/rational.h>
17 #include <linux/dmaengine.h>
18 #include <linux/dma/dw.h>
22 #define PCI_DEVICE_ID_INTEL_QRK_UARTx 0x0936
24 #define PCI_DEVICE_ID_INTEL_BYT_UART1 0x0f0a
25 #define PCI_DEVICE_ID_INTEL_BYT_UART2 0x0f0c
27 #define PCI_DEVICE_ID_INTEL_BSW_UART1 0x228a
28 #define PCI_DEVICE_ID_INTEL_BSW_UART2 0x228c
30 #define PCI_DEVICE_ID_INTEL_BDW_UART1 0x9ce3
31 #define PCI_DEVICE_ID_INTEL_BDW_UART2 0x9ce4
33 /* Intel LPSS specific registers */
35 #define BYT_PRV_CLK 0x800
36 #define BYT_PRV_CLK_EN BIT(0)
37 #define BYT_PRV_CLK_M_VAL_SHIFT 1
38 #define BYT_PRV_CLK_N_VAL_SHIFT 16
39 #define BYT_PRV_CLK_UPDATE BIT(31)
41 #define BYT_TX_OVF_INT 0x820
42 #define BYT_TX_OVF_INT_MASK BIT(1)
46 struct lpss8250_board {
48 unsigned int base_baud;
49 int (*setup)(struct lpss8250 *, struct uart_port *p);
50 void (*exit)(struct lpss8250 *);
55 struct lpss8250_board *board;
58 struct uart_8250_dma dma;
59 struct dw_dma_chip dma_chip;
60 struct dw_dma_slave dma_param;
64 static void byt_set_termios(struct uart_port *p, struct ktermios *termios,
67 unsigned int baud = tty_termios_baud_rate(termios);
68 struct lpss8250 *lpss = p->private_data;
69 unsigned long fref = lpss->board->freq, fuart = baud * 16;
70 unsigned long w = BIT(15) - 1;
74 /* Gracefully handle the B0 case: fall back to B9600 */
75 fuart = fuart ? fuart : 9600 * 16;
77 /* Get Fuart closer to Fref */
78 fuart *= rounddown_pow_of_two(fref / fuart);
81 * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
82 * dividers must be adjusted.
84 * uartclk = (m / n) * 100 MHz, where m <= n
86 rational_best_approximation(fuart, fref, w, w, &m, &n);
90 reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT);
91 writel(reg, p->membase + BYT_PRV_CLK);
92 reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE;
93 writel(reg, p->membase + BYT_PRV_CLK);
95 p->status &= ~UPSTAT_AUTOCTS;
96 if (termios->c_cflag & CRTSCTS)
97 p->status |= UPSTAT_AUTOCTS;
99 serial8250_do_set_termios(p, termios, old);
102 static unsigned int byt_get_mctrl(struct uart_port *port)
104 unsigned int ret = serial8250_do_get_mctrl(port);
106 /* Force DCD and DSR signals to permanently be reported as active */
107 ret |= TIOCM_CAR | TIOCM_DSR;
112 static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
114 struct dw_dma_slave *param = &lpss->dma_param;
115 struct uart_8250_port *up = up_to_u8250p(port);
116 struct pci_dev *pdev = to_pci_dev(port->dev);
117 unsigned int dma_devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0);
118 struct pci_dev *dma_dev = pci_get_slot(pdev->bus, dma_devfn);
120 switch (pdev->device) {
121 case PCI_DEVICE_ID_INTEL_BYT_UART1:
122 case PCI_DEVICE_ID_INTEL_BSW_UART1:
123 case PCI_DEVICE_ID_INTEL_BDW_UART1:
127 case PCI_DEVICE_ID_INTEL_BYT_UART2:
128 case PCI_DEVICE_ID_INTEL_BSW_UART2:
129 case PCI_DEVICE_ID_INTEL_BDW_UART2:
137 param->dma_dev = &dma_dev->dev;
141 /* TODO: Detect FIFO size automaticaly for DesignWare 8250 */
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 #ifdef CONFIG_SERIAL_8250_DMA
157 static const struct dw_dma_platform_data qrk_serial_dma_pdata = {
160 .chan_allocation_order = CHAN_ALLOCATION_ASCENDING,
161 .chan_priority = CHAN_PRIORITY_ASCENDING,
168 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
170 struct uart_8250_dma *dma = &lpss->dma;
171 struct dw_dma_chip *chip = &lpss->dma_chip;
172 struct dw_dma_slave *param = &lpss->dma_param;
173 struct pci_dev *pdev = to_pci_dev(port->dev);
176 chip->dev = &pdev->dev;
177 chip->irq = pci_irq_vector(pdev, 0);
178 chip->regs = pci_ioremap_bar(pdev, 1);
179 chip->pdata = &qrk_serial_dma_pdata;
181 /* Falling back to PIO mode if DMA probing fails */
182 ret = dw_dma_probe(chip);
186 pci_try_set_mwi(pdev);
188 /* Special DMA address for UART */
189 dma->rx_dma_addr = 0xfffff000;
190 dma->tx_dma_addr = 0xfffff000;
192 param->dma_dev = &pdev->dev;
195 param->hs_polarity = true;
197 lpss->dma_maxburst = 8;
200 static void qrk_serial_exit_dma(struct lpss8250 *lpss)
202 struct dw_dma_slave *param = &lpss->dma_param;
206 dw_dma_remove(&lpss->dma_chip);
208 #else /* CONFIG_SERIAL_8250_DMA */
209 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}
210 static void qrk_serial_exit_dma(struct lpss8250 *lpss) {}
211 #endif /* !CONFIG_SERIAL_8250_DMA */
213 static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
215 struct pci_dev *pdev = to_pci_dev(port->dev);
218 pci_set_master(pdev);
220 ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
224 port->irq = pci_irq_vector(pdev, 0);
226 qrk_serial_setup_dma(lpss, port);
230 static void qrk_serial_exit(struct lpss8250 *lpss)
232 qrk_serial_exit_dma(lpss);
235 static bool lpss8250_dma_filter(struct dma_chan *chan, void *param)
237 struct dw_dma_slave *dws = param;
239 if (dws->dma_dev != chan->device->dev)
246 static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port)
248 struct uart_8250_dma *dma = &lpss->dma;
249 struct dw_dma_slave *rx_param, *tx_param;
250 struct device *dev = port->port.dev;
252 if (!lpss->dma_param.dma_dev)
255 rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
259 tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
263 *rx_param = lpss->dma_param;
264 dma->rxconf.src_maxburst = lpss->dma_maxburst;
266 *tx_param = lpss->dma_param;
267 dma->txconf.dst_maxburst = lpss->dma_maxburst;
269 dma->fn = lpss8250_dma_filter;
270 dma->rx_param = rx_param;
271 dma->tx_param = tx_param;
277 static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
279 struct uart_8250_port uart;
280 struct lpss8250 *lpss;
283 ret = pcim_enable_device(pdev);
287 lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL);
291 lpss->board = (struct lpss8250_board *)id->driver_data;
293 memset(&uart, 0, sizeof(struct uart_8250_port));
295 uart.port.dev = &pdev->dev;
296 uart.port.irq = pdev->irq;
297 uart.port.private_data = lpss;
298 uart.port.type = PORT_16550A;
299 uart.port.iotype = UPIO_MEM;
300 uart.port.regshift = 2;
301 uart.port.uartclk = lpss->board->base_baud * 16;
302 uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
303 uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
304 uart.port.mapbase = pci_resource_start(pdev, 0);
305 uart.port.membase = pcim_iomap(pdev, 0, 0);
306 if (!uart.port.membase)
309 ret = lpss->board->setup(lpss, &uart.port);
313 ret = lpss8250_dma_setup(lpss, &uart);
317 ret = serial8250_register_8250_port(&uart);
323 pci_set_drvdata(pdev, lpss);
327 if (lpss->board->exit)
328 lpss->board->exit(lpss);
332 static void lpss8250_remove(struct pci_dev *pdev)
334 struct lpss8250 *lpss = pci_get_drvdata(pdev);
336 serial8250_unregister_port(lpss->line);
338 if (lpss->board->exit)
339 lpss->board->exit(lpss);
342 static const struct lpss8250_board byt_board = {
344 .base_baud = 2764800,
345 .setup = byt_serial_setup,
348 static const struct lpss8250_board qrk_board = {
350 .base_baud = 2764800,
351 .setup = qrk_serial_setup,
352 .exit = qrk_serial_exit,
355 #define LPSS_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
357 static const struct pci_device_id pci_ids[] = {
358 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_QRK_UARTx, qrk_board),
359 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART1, byt_board),
360 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART2, byt_board),
361 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART1, byt_board),
362 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART2, byt_board),
363 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART1, byt_board),
364 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART2, byt_board),
367 MODULE_DEVICE_TABLE(pci, pci_ids);
369 static struct pci_driver lpss8250_pci_driver = {
372 .probe = lpss8250_probe,
373 .remove = lpss8250_remove,
376 module_pci_driver(lpss8250_pci_driver);
378 MODULE_AUTHOR("Intel Corporation");
379 MODULE_LICENSE("GPL v2");
380 MODULE_DESCRIPTION("Intel LPSS UART driver");