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>
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_BDW_UART1 0x9ce3
28 #define PCI_DEVICE_ID_INTEL_BDW_UART2 0x9ce4
30 /* Intel LPSS specific registers */
32 #define BYT_PRV_CLK 0x800
33 #define BYT_PRV_CLK_EN BIT(0)
34 #define BYT_PRV_CLK_M_VAL_SHIFT 1
35 #define BYT_PRV_CLK_N_VAL_SHIFT 16
36 #define BYT_PRV_CLK_UPDATE BIT(31)
38 #define BYT_TX_OVF_INT 0x820
39 #define BYT_TX_OVF_INT_MASK BIT(1)
43 struct lpss8250_board {
45 unsigned int base_baud;
46 int (*setup)(struct lpss8250 *, struct uart_port *p);
47 void (*exit)(struct lpss8250 *);
52 struct lpss8250_board *board;
55 struct uart_8250_dma dma;
56 struct dw_dma_chip dma_chip;
57 struct dw_dma_slave dma_param;
61 static void byt_set_termios(struct uart_port *p, struct ktermios *termios,
64 unsigned int baud = tty_termios_baud_rate(termios);
65 struct lpss8250 *lpss = p->private_data;
66 unsigned long fref = lpss->board->freq, fuart = baud * 16;
67 unsigned long w = BIT(15) - 1;
71 /* Gracefully handle the B0 case: fall back to B9600 */
72 fuart = fuart ? fuart : 9600 * 16;
74 /* Get Fuart closer to Fref */
75 fuart *= rounddown_pow_of_two(fref / fuart);
78 * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
79 * dividers must be adjusted.
81 * uartclk = (m / n) * 100 MHz, where m <= n
83 rational_best_approximation(fuart, fref, w, w, &m, &n);
87 reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT);
88 writel(reg, p->membase + BYT_PRV_CLK);
89 reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE;
90 writel(reg, p->membase + BYT_PRV_CLK);
92 p->status &= ~UPSTAT_AUTOCTS;
93 if (termios->c_cflag & CRTSCTS)
94 p->status |= UPSTAT_AUTOCTS;
96 serial8250_do_set_termios(p, termios, old);
99 static unsigned int byt_get_mctrl(struct uart_port *port)
101 unsigned int ret = serial8250_do_get_mctrl(port);
103 /* Force DCD and DSR signals to permanently be reported as active */
104 ret |= TIOCM_CAR | TIOCM_DSR;
109 static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
111 struct dw_dma_slave *param = &lpss->dma_param;
112 struct uart_8250_port *up = up_to_u8250p(port);
113 struct pci_dev *pdev = to_pci_dev(port->dev);
114 unsigned int dma_devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0);
115 struct pci_dev *dma_dev = pci_get_slot(pdev->bus, dma_devfn);
117 switch (pdev->device) {
118 case PCI_DEVICE_ID_INTEL_BYT_UART1:
119 case PCI_DEVICE_ID_INTEL_BSW_UART1:
120 case PCI_DEVICE_ID_INTEL_BDW_UART1:
124 case PCI_DEVICE_ID_INTEL_BYT_UART2:
125 case PCI_DEVICE_ID_INTEL_BSW_UART2:
126 case PCI_DEVICE_ID_INTEL_BDW_UART2:
134 param->dma_dev = &dma_dev->dev;
138 /* TODO: Detect FIFO size automaticaly for DesignWare 8250 */
142 lpss->dma_maxburst = 16;
144 port->set_termios = byt_set_termios;
145 port->get_mctrl = byt_get_mctrl;
147 /* Disable TX counter interrupts */
148 writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT);
153 #ifdef CONFIG_SERIAL_8250_DMA
154 static const struct dw_dma_platform_data qrk_serial_dma_pdata = {
157 .chan_allocation_order = CHAN_ALLOCATION_ASCENDING,
158 .chan_priority = CHAN_PRIORITY_ASCENDING,
165 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
167 struct uart_8250_dma *dma = &lpss->dma;
168 struct dw_dma_chip *chip = &lpss->dma_chip;
169 struct dw_dma_slave *param = &lpss->dma_param;
170 struct pci_dev *pdev = to_pci_dev(port->dev);
173 chip->dev = &pdev->dev;
174 chip->irq = pci_irq_vector(pdev, 0);
175 chip->regs = pci_ioremap_bar(pdev, 1);
176 chip->pdata = &qrk_serial_dma_pdata;
178 /* Falling back to PIO mode if DMA probing fails */
179 ret = dw_dma_probe(chip);
183 pci_try_set_mwi(pdev);
185 /* Special DMA address for UART */
186 dma->rx_dma_addr = 0xfffff000;
187 dma->tx_dma_addr = 0xfffff000;
189 param->dma_dev = &pdev->dev;
192 param->hs_polarity = true;
194 lpss->dma_maxburst = 8;
197 static void qrk_serial_exit_dma(struct lpss8250 *lpss)
199 struct dw_dma_slave *param = &lpss->dma_param;
203 dw_dma_remove(&lpss->dma_chip);
205 #else /* CONFIG_SERIAL_8250_DMA */
206 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}
207 static void qrk_serial_exit_dma(struct lpss8250 *lpss) {}
208 #endif /* !CONFIG_SERIAL_8250_DMA */
210 static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
212 struct pci_dev *pdev = to_pci_dev(port->dev);
215 pci_set_master(pdev);
217 ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
221 port->irq = pci_irq_vector(pdev, 0);
223 qrk_serial_setup_dma(lpss, port);
227 static void qrk_serial_exit(struct lpss8250 *lpss)
229 qrk_serial_exit_dma(lpss);
232 static bool lpss8250_dma_filter(struct dma_chan *chan, void *param)
234 struct dw_dma_slave *dws = param;
236 if (dws->dma_dev != chan->device->dev)
243 static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port)
245 struct uart_8250_dma *dma = &lpss->dma;
246 struct dw_dma_slave *rx_param, *tx_param;
247 struct device *dev = port->port.dev;
249 if (!lpss->dma_param.dma_dev)
252 rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
256 tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
260 *rx_param = lpss->dma_param;
261 dma->rxconf.src_maxburst = lpss->dma_maxburst;
263 *tx_param = lpss->dma_param;
264 dma->txconf.dst_maxburst = lpss->dma_maxburst;
266 dma->fn = lpss8250_dma_filter;
267 dma->rx_param = rx_param;
268 dma->tx_param = tx_param;
274 static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
276 struct uart_8250_port uart;
277 struct lpss8250 *lpss;
280 ret = pcim_enable_device(pdev);
284 lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL);
288 lpss->board = (struct lpss8250_board *)id->driver_data;
290 memset(&uart, 0, sizeof(struct uart_8250_port));
292 uart.port.dev = &pdev->dev;
293 uart.port.irq = pdev->irq;
294 uart.port.private_data = lpss;
295 uart.port.type = PORT_16550A;
296 uart.port.iotype = UPIO_MEM;
297 uart.port.regshift = 2;
298 uart.port.uartclk = lpss->board->base_baud * 16;
299 uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
300 uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
301 uart.port.mapbase = pci_resource_start(pdev, 0);
302 uart.port.membase = pcim_iomap(pdev, 0, 0);
303 if (!uart.port.membase)
306 ret = lpss->board->setup(lpss, &uart.port);
310 ret = lpss8250_dma_setup(lpss, &uart);
314 ret = serial8250_register_8250_port(&uart);
320 pci_set_drvdata(pdev, lpss);
324 if (lpss->board->exit)
325 lpss->board->exit(lpss);
329 static void lpss8250_remove(struct pci_dev *pdev)
331 struct lpss8250 *lpss = pci_get_drvdata(pdev);
333 serial8250_unregister_port(lpss->line);
335 if (lpss->board->exit)
336 lpss->board->exit(lpss);
339 static const struct lpss8250_board byt_board = {
341 .base_baud = 2764800,
342 .setup = byt_serial_setup,
345 static const struct lpss8250_board qrk_board = {
347 .base_baud = 2764800,
348 .setup = qrk_serial_setup,
349 .exit = qrk_serial_exit,
352 #define LPSS_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
354 static const struct pci_device_id pci_ids[] = {
355 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_QRK_UARTx, qrk_board),
356 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART1, byt_board),
357 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART2, byt_board),
358 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART1, byt_board),
359 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART2, byt_board),
360 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART1, byt_board),
361 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART2, byt_board),
364 MODULE_DEVICE_TABLE(pci, pci_ids);
366 static struct pci_driver lpss8250_pci_driver = {
369 .probe = lpss8250_probe,
370 .remove = lpss8250_remove,
373 module_pci_driver(lpss8250_pci_driver);
375 MODULE_AUTHOR("Intel Corporation");
376 MODULE_LICENSE("GPL v2");
377 MODULE_DESCRIPTION("Intel LPSS UART driver");