1 /*
2 * 8250_mid.c - Driver for UART on Intel Penwell and various other Intel SOCs
3 *
4 * Copyright (C) 2015 Intel Corporation
5 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
6 *
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.
10 */
11
12 #include <linux/rational.h>
13 #include <linux/module.h>
14 #include <linux/pci.h>
15
16 #include <linux/dma/hsu.h>
17 #include <linux/8250_pci.h>
18
19 #include "8250.h"
20
21 #define PCI_DEVICE_ID_INTEL_PNW_UART1 0x081b
22 #define PCI_DEVICE_ID_INTEL_PNW_UART2 0x081c
23 #define PCI_DEVICE_ID_INTEL_PNW_UART3 0x081d
24 #define PCI_DEVICE_ID_INTEL_TNG_UART 0x1191
25 #define PCI_DEVICE_ID_INTEL_DNV_UART 0x19d8
26
27 /* Intel MID Specific registers */
28 #define INTEL_MID_UART_DNV_FISR 0x08
29 #define INTEL_MID_UART_PS 0x30
30 #define INTEL_MID_UART_MUL 0x34
31 #define INTEL_MID_UART_DIV 0x38
32
33 struct mid8250;
34
35 struct mid8250_board {
36 unsigned int flags;
37 unsigned long freq;
38 unsigned int base_baud;
39 int (*setup)(struct mid8250 *, struct uart_port *p);
40 void (*exit)(struct mid8250 *);
41 };
42
43 struct mid8250 {
44 int line;
45 int dma_index;
46 struct pci_dev *dma_dev;
47 struct uart_8250_dma dma;
48 struct mid8250_board *board;
49 struct hsu_dma_chip dma_chip;
50 };
51
52 /*****************************************************************************/
53
pnw_setup(struct mid8250 * mid,struct uart_port * p)54 static int pnw_setup(struct mid8250 *mid, struct uart_port *p)
55 {
56 struct pci_dev *pdev = to_pci_dev(p->dev);
57
58 switch (pdev->device) {
59 case PCI_DEVICE_ID_INTEL_PNW_UART1:
60 mid->dma_index = 0;
61 break;
62 case PCI_DEVICE_ID_INTEL_PNW_UART2:
63 mid->dma_index = 1;
64 break;
65 case PCI_DEVICE_ID_INTEL_PNW_UART3:
66 mid->dma_index = 2;
67 break;
68 default:
69 return -EINVAL;
70 }
71
72 mid->dma_dev = pci_get_slot(pdev->bus,
73 PCI_DEVFN(PCI_SLOT(pdev->devfn), 3));
74 return 0;
75 }
76
tng_setup(struct mid8250 * mid,struct uart_port * p)77 static int tng_setup(struct mid8250 *mid, struct uart_port *p)
78 {
79 struct pci_dev *pdev = to_pci_dev(p->dev);
80 int index = PCI_FUNC(pdev->devfn);
81
82 /* Currently no support for HSU port0 */
83 if (index-- == 0)
84 return -ENODEV;
85
86 mid->dma_index = index;
87 mid->dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(5, 0));
88 return 0;
89 }
90
dnv_handle_irq(struct uart_port * p)91 static int dnv_handle_irq(struct uart_port *p)
92 {
93 struct mid8250 *mid = p->private_data;
94 unsigned int fisr = serial_port_in(p, INTEL_MID_UART_DNV_FISR);
95 int ret = IRQ_NONE;
96
97 if (fisr & BIT(2))
98 ret |= hsu_dma_irq(&mid->dma_chip, 1);
99 if (fisr & BIT(1))
100 ret |= hsu_dma_irq(&mid->dma_chip, 0);
101 if (fisr & BIT(0))
102 ret |= serial8250_handle_irq(p, serial_port_in(p, UART_IIR));
103 return ret;
104 }
105
106 #define DNV_DMA_CHAN_OFFSET 0x80
107
dnv_setup(struct mid8250 * mid,struct uart_port * p)108 static int dnv_setup(struct mid8250 *mid, struct uart_port *p)
109 {
110 struct hsu_dma_chip *chip = &mid->dma_chip;
111 struct pci_dev *pdev = to_pci_dev(p->dev);
112 unsigned int bar = FL_GET_BASE(mid->board->flags);
113 int ret;
114
115 chip->dev = &pdev->dev;
116 chip->irq = pdev->irq;
117 chip->regs = p->membase;
118 chip->length = pci_resource_len(pdev, bar);
119 chip->offset = DNV_DMA_CHAN_OFFSET;
120
121 /* Falling back to PIO mode if DMA probing fails */
122 ret = hsu_dma_probe(chip);
123 if (ret)
124 return 0;
125
126 mid->dma_dev = pdev;
127
128 p->handle_irq = dnv_handle_irq;
129 return 0;
130 }
131
dnv_exit(struct mid8250 * mid)132 static void dnv_exit(struct mid8250 *mid)
133 {
134 if (!mid->dma_dev)
135 return;
136 hsu_dma_remove(&mid->dma_chip);
137 }
138
139 /*****************************************************************************/
140
mid8250_set_termios(struct uart_port * p,struct ktermios * termios,struct ktermios * old)141 static void mid8250_set_termios(struct uart_port *p,
142 struct ktermios *termios,
143 struct ktermios *old)
144 {
145 unsigned int baud = tty_termios_baud_rate(termios);
146 struct mid8250 *mid = p->private_data;
147 unsigned short ps = 16;
148 unsigned long fuart = baud * ps;
149 unsigned long w = BIT(24) - 1;
150 unsigned long mul, div;
151
152 if (mid->board->freq < fuart) {
153 /* Find prescaler value that satisfies Fuart < Fref */
154 if (mid->board->freq > baud)
155 ps = mid->board->freq / baud; /* baud rate too high */
156 else
157 ps = 1; /* PLL case */
158 fuart = baud * ps;
159 } else {
160 /* Get Fuart closer to Fref */
161 fuart *= rounddown_pow_of_two(mid->board->freq / fuart);
162 }
163
164 rational_best_approximation(fuart, mid->board->freq, w, w, &mul, &div);
165 p->uartclk = fuart * 16 / ps; /* core uses ps = 16 always */
166
167 writel(ps, p->membase + INTEL_MID_UART_PS); /* set PS */
168 writel(mul, p->membase + INTEL_MID_UART_MUL); /* set MUL */
169 writel(div, p->membase + INTEL_MID_UART_DIV);
170
171 serial8250_do_set_termios(p, termios, old);
172 }
173
mid8250_dma_filter(struct dma_chan * chan,void * param)174 static bool mid8250_dma_filter(struct dma_chan *chan, void *param)
175 {
176 struct hsu_dma_slave *s = param;
177
178 if (s->dma_dev != chan->device->dev || s->chan_id != chan->chan_id)
179 return false;
180
181 chan->private = s;
182 return true;
183 }
184
mid8250_dma_setup(struct mid8250 * mid,struct uart_8250_port * port)185 static int mid8250_dma_setup(struct mid8250 *mid, struct uart_8250_port *port)
186 {
187 struct uart_8250_dma *dma = &mid->dma;
188 struct device *dev = port->port.dev;
189 struct hsu_dma_slave *rx_param;
190 struct hsu_dma_slave *tx_param;
191
192 if (!mid->dma_dev)
193 return 0;
194
195 rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
196 if (!rx_param)
197 return -ENOMEM;
198
199 tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
200 if (!tx_param)
201 return -ENOMEM;
202
203 rx_param->chan_id = mid->dma_index * 2 + 1;
204 tx_param->chan_id = mid->dma_index * 2;
205
206 dma->rxconf.src_maxburst = 64;
207 dma->txconf.dst_maxburst = 64;
208
209 rx_param->dma_dev = &mid->dma_dev->dev;
210 tx_param->dma_dev = &mid->dma_dev->dev;
211
212 dma->fn = mid8250_dma_filter;
213 dma->rx_param = rx_param;
214 dma->tx_param = tx_param;
215
216 port->dma = dma;
217 return 0;
218 }
219
mid8250_probe(struct pci_dev * pdev,const struct pci_device_id * id)220 static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
221 {
222 struct uart_8250_port uart;
223 struct mid8250 *mid;
224 unsigned int bar;
225 int ret;
226
227 ret = pcim_enable_device(pdev);
228 if (ret)
229 return ret;
230
231 pci_set_master(pdev);
232
233 mid = devm_kzalloc(&pdev->dev, sizeof(*mid), GFP_KERNEL);
234 if (!mid)
235 return -ENOMEM;
236
237 mid->board = (struct mid8250_board *)id->driver_data;
238 bar = FL_GET_BASE(mid->board->flags);
239
240 memset(&uart, 0, sizeof(struct uart_8250_port));
241
242 uart.port.dev = &pdev->dev;
243 uart.port.irq = pdev->irq;
244 uart.port.private_data = mid;
245 uart.port.type = PORT_16750;
246 uart.port.iotype = UPIO_MEM;
247 uart.port.uartclk = mid->board->base_baud * 16;
248 uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
249 uart.port.set_termios = mid8250_set_termios;
250
251 uart.port.mapbase = pci_resource_start(pdev, bar);
252 uart.port.membase = pcim_iomap(pdev, bar, 0);
253 if (!uart.port.membase)
254 return -ENOMEM;
255
256 if (mid->board->setup) {
257 ret = mid->board->setup(mid, &uart.port);
258 if (ret)
259 return ret;
260 }
261
262 ret = mid8250_dma_setup(mid, &uart);
263 if (ret)
264 goto err;
265
266 ret = serial8250_register_8250_port(&uart);
267 if (ret < 0)
268 goto err;
269
270 mid->line = ret;
271
272 pci_set_drvdata(pdev, mid);
273 return 0;
274 err:
275 if (mid->board->exit)
276 mid->board->exit(mid);
277 return ret;
278 }
279
mid8250_remove(struct pci_dev * pdev)280 static void mid8250_remove(struct pci_dev *pdev)
281 {
282 struct mid8250 *mid = pci_get_drvdata(pdev);
283
284 if (mid->board->exit)
285 mid->board->exit(mid);
286
287 serial8250_unregister_port(mid->line);
288 }
289
290 static const struct mid8250_board pnw_board = {
291 .flags = FL_BASE0,
292 .freq = 50000000,
293 .base_baud = 115200,
294 .setup = pnw_setup,
295 };
296
297 static const struct mid8250_board tng_board = {
298 .flags = FL_BASE0,
299 .freq = 38400000,
300 .base_baud = 1843200,
301 .setup = tng_setup,
302 };
303
304 static const struct mid8250_board dnv_board = {
305 .flags = FL_BASE1,
306 .freq = 133333333,
307 .base_baud = 115200,
308 .setup = dnv_setup,
309 .exit = dnv_exit,
310 };
311
312 #define MID_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
313
314 static const struct pci_device_id pci_ids[] = {
315 MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART1, pnw_board),
316 MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART2, pnw_board),
317 MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART3, pnw_board),
318 MID_DEVICE(PCI_DEVICE_ID_INTEL_TNG_UART, tng_board),
319 MID_DEVICE(PCI_DEVICE_ID_INTEL_DNV_UART, dnv_board),
320 { },
321 };
322 MODULE_DEVICE_TABLE(pci, pci_ids);
323
324 static struct pci_driver mid8250_pci_driver = {
325 .name = "8250_mid",
326 .id_table = pci_ids,
327 .probe = mid8250_probe,
328 .remove = mid8250_remove,
329 };
330
331 module_pci_driver(mid8250_pci_driver);
332
333 MODULE_AUTHOR("Intel Corporation");
334 MODULE_LICENSE("GPL v2");
335 MODULE_DESCRIPTION("Intel MID UART driver");
336