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/platform_data/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);
54 struct lpss8250_board *board;
57 struct uart_8250_dma dma;
58 struct dw_dma_slave dma_param;
62 static void byt_set_termios(struct uart_port *p, struct ktermios *termios,
65 unsigned int baud = tty_termios_baud_rate(termios);
66 struct lpss8250 *lpss = p->private_data;
67 unsigned long fref = lpss->board->freq, fuart = baud * 16;
68 unsigned long w = BIT(15) - 1;
72 /* Gracefully handle the B0 case: fall back to B9600 */
73 fuart = fuart ? fuart : 9600 * 16;
75 /* Get Fuart closer to Fref */
76 fuart *= rounddown_pow_of_two(fref / fuart);
79 * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
80 * dividers must be adjusted.
82 * uartclk = (m / n) * 100 MHz, where m <= n
84 rational_best_approximation(fuart, fref, w, w, &m, &n);
88 reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT);
89 writel(reg, p->membase + BYT_PRV_CLK);
90 reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE;
91 writel(reg, p->membase + BYT_PRV_CLK);
93 p->status &= ~UPSTAT_AUTOCTS;
94 if (termios->c_cflag & CRTSCTS)
95 p->status |= UPSTAT_AUTOCTS;
97 serial8250_do_set_termios(p, termios, old);
100 static unsigned int byt_get_mctrl(struct uart_port *port)
102 unsigned int ret = serial8250_do_get_mctrl(port);
104 /* Force DCD and DSR signals to permanently be reported as active */
105 ret |= TIOCM_CAR | TIOCM_DSR;
110 static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
112 struct dw_dma_slave *param = &lpss->dma_param;
113 struct uart_8250_port *up = up_to_u8250p(port);
114 struct pci_dev *pdev = to_pci_dev(port->dev);
115 unsigned int dma_devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0);
116 struct pci_dev *dma_dev = pci_get_slot(pdev->bus, dma_devfn);
118 switch (pdev->device) {
119 case PCI_DEVICE_ID_INTEL_BYT_UART1:
120 case PCI_DEVICE_ID_INTEL_BSW_UART1:
121 case PCI_DEVICE_ID_INTEL_BDW_UART1:
125 case PCI_DEVICE_ID_INTEL_BYT_UART2:
126 case PCI_DEVICE_ID_INTEL_BSW_UART2:
127 case PCI_DEVICE_ID_INTEL_BDW_UART2:
135 param->dma_dev = &dma_dev->dev;
139 /* TODO: Detect FIFO size automaticaly for DesignWare 8250 */
143 lpss->dma_maxburst = 16;
145 port->set_termios = byt_set_termios;
146 port->get_mctrl = byt_get_mctrl;
148 /* Disable TX counter interrupts */
149 writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT);
154 static bool lpss8250_dma_filter(struct dma_chan *chan, void *param)
156 struct dw_dma_slave *dws = param;
158 if (dws->dma_dev != chan->device->dev)
165 static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port)
167 struct uart_8250_dma *dma = &lpss->dma;
168 struct dw_dma_slave *rx_param, *tx_param;
169 struct device *dev = port->port.dev;
171 if (!lpss->dma_param.dma_dev)
174 rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
178 tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
182 *rx_param = lpss->dma_param;
183 dma->rxconf.src_maxburst = lpss->dma_maxburst;
185 *tx_param = lpss->dma_param;
186 dma->txconf.dst_maxburst = lpss->dma_maxburst;
188 dma->fn = lpss8250_dma_filter;
189 dma->rx_param = rx_param;
190 dma->tx_param = tx_param;
196 static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
198 struct uart_8250_port uart;
199 struct lpss8250 *lpss;
202 ret = pcim_enable_device(pdev);
206 pci_set_master(pdev);
208 lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL);
212 lpss->board = (struct lpss8250_board *)id->driver_data;
214 memset(&uart, 0, sizeof(struct uart_8250_port));
216 uart.port.dev = &pdev->dev;
217 uart.port.irq = pdev->irq;
218 uart.port.private_data = lpss;
219 uart.port.type = PORT_16550A;
220 uart.port.iotype = UPIO_MEM;
221 uart.port.regshift = 2;
222 uart.port.uartclk = lpss->board->base_baud * 16;
223 uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
224 uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
225 uart.port.mapbase = pci_resource_start(pdev, 0);
226 uart.port.membase = pcim_iomap(pdev, 0, 0);
227 if (!uart.port.membase)
230 ret = lpss->board->setup(lpss, &uart.port);
234 ret = lpss8250_dma_setup(lpss, &uart);
238 ret = serial8250_register_8250_port(&uart);
244 pci_set_drvdata(pdev, lpss);
248 static void lpss8250_remove(struct pci_dev *pdev)
250 struct lpss8250 *lpss = pci_get_drvdata(pdev);
252 serial8250_unregister_port(lpss->line);
255 static const struct lpss8250_board byt_board = {
257 .base_baud = 2764800,
258 .setup = byt_serial_setup,
261 static const struct lpss8250_board qrk_board = {
263 .base_baud = 2764800,
266 #define LPSS_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
268 static const struct pci_device_id pci_ids[] = {
269 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_QRK_UARTx, qrk_board),
270 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART1, byt_board),
271 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART2, byt_board),
272 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART1, byt_board),
273 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART2, byt_board),
274 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART1, byt_board),
275 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART2, byt_board),
278 MODULE_DEVICE_TABLE(pci, pci_ids);
280 static struct pci_driver lpss8250_pci_driver = {
283 .probe = lpss8250_probe,
284 .remove = lpss8250_remove,
287 module_pci_driver(lpss8250_pci_driver);
289 MODULE_AUTHOR("Intel Corporation");
290 MODULE_LICENSE("GPL v2");
291 MODULE_DESCRIPTION("Intel LPSS UART driver");