xref: /openbmc/linux/samples/vfio-mdev/mtty.c (revision 2c6467d2)
1 /*
2  * Mediated virtual PCI serial host device driver
3  *
4  * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
5  *     Author: Neo Jia <cjia@nvidia.com>
6  *             Kirti Wankhede <kwankhede@nvidia.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  *
12  * Sample driver that creates mdev device that simulates serial port over PCI
13  * card.
14  *
15  */
16 
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/device.h>
20 #include <linux/kernel.h>
21 #include <linux/fs.h>
22 #include <linux/poll.h>
23 #include <linux/slab.h>
24 #include <linux/cdev.h>
25 #include <linux/sched.h>
26 #include <linux/wait.h>
27 #include <linux/uuid.h>
28 #include <linux/vfio.h>
29 #include <linux/iommu.h>
30 #include <linux/sysfs.h>
31 #include <linux/ctype.h>
32 #include <linux/file.h>
33 #include <linux/mdev.h>
34 #include <linux/pci.h>
35 #include <linux/serial.h>
36 #include <uapi/linux/serial_reg.h>
37 #include <linux/eventfd.h>
38 /*
39  * #defines
40  */
41 
42 #define VERSION_STRING  "0.1"
43 #define DRIVER_AUTHOR   "NVIDIA Corporation"
44 
45 #define MTTY_CLASS_NAME "mtty"
46 
47 #define MTTY_NAME       "mtty"
48 
49 #define MTTY_STRING_LEN		16
50 
51 #define MTTY_CONFIG_SPACE_SIZE  0xff
52 #define MTTY_IO_BAR_SIZE        0x8
53 #define MTTY_MMIO_BAR_SIZE      0x100000
54 
55 #define STORE_LE16(addr, val)   (*(u16 *)addr = val)
56 #define STORE_LE32(addr, val)   (*(u32 *)addr = val)
57 
58 #define MAX_FIFO_SIZE   16
59 
60 #define CIRCULAR_BUF_INC_IDX(idx)    (idx = (idx + 1) & (MAX_FIFO_SIZE - 1))
61 
62 #define MTTY_VFIO_PCI_OFFSET_SHIFT   40
63 
64 #define MTTY_VFIO_PCI_OFFSET_TO_INDEX(off)   (off >> MTTY_VFIO_PCI_OFFSET_SHIFT)
65 #define MTTY_VFIO_PCI_INDEX_TO_OFFSET(index) \
66 				((u64)(index) << MTTY_VFIO_PCI_OFFSET_SHIFT)
67 #define MTTY_VFIO_PCI_OFFSET_MASK    \
68 				(((u64)(1) << MTTY_VFIO_PCI_OFFSET_SHIFT) - 1)
69 #define MAX_MTTYS	24
70 
71 /*
72  * Global Structures
73  */
74 
75 struct mtty_dev {
76 	dev_t		vd_devt;
77 	struct class	*vd_class;
78 	struct cdev	vd_cdev;
79 	struct idr	vd_idr;
80 	struct device	dev;
81 } mtty_dev;
82 
83 struct mdev_region_info {
84 	u64 start;
85 	u64 phys_start;
86 	u32 size;
87 	u64 vfio_offset;
88 };
89 
90 #if defined(DEBUG_REGS)
91 const char *wr_reg[] = {
92 	"TX",
93 	"IER",
94 	"FCR",
95 	"LCR",
96 	"MCR",
97 	"LSR",
98 	"MSR",
99 	"SCR"
100 };
101 
102 const char *rd_reg[] = {
103 	"RX",
104 	"IER",
105 	"IIR",
106 	"LCR",
107 	"MCR",
108 	"LSR",
109 	"MSR",
110 	"SCR"
111 };
112 #endif
113 
114 /* loop back buffer */
115 struct rxtx {
116 	u8 fifo[MAX_FIFO_SIZE];
117 	u8 head, tail;
118 	u8 count;
119 };
120 
121 struct serial_port {
122 	u8 uart_reg[8];         /* 8 registers */
123 	struct rxtx rxtx;       /* loop back buffer */
124 	bool dlab;
125 	bool overrun;
126 	u16 divisor;
127 	u8 fcr;                 /* FIFO control register */
128 	u8 max_fifo_size;
129 	u8 intr_trigger_level;  /* interrupt trigger level */
130 };
131 
132 /* State of each mdev device */
133 struct mdev_state {
134 	int irq_fd;
135 	struct eventfd_ctx *intx_evtfd;
136 	struct eventfd_ctx *msi_evtfd;
137 	int irq_index;
138 	u8 *vconfig;
139 	struct mutex ops_lock;
140 	struct mdev_device *mdev;
141 	struct mdev_region_info region_info[VFIO_PCI_NUM_REGIONS];
142 	u32 bar_mask[VFIO_PCI_NUM_REGIONS];
143 	struct list_head next;
144 	struct serial_port s[2];
145 	struct mutex rxtx_lock;
146 	struct vfio_device_info dev_info;
147 	int nr_ports;
148 };
149 
150 struct mutex mdev_list_lock;
151 struct list_head mdev_devices_list;
152 
153 static const struct file_operations vd_fops = {
154 	.owner          = THIS_MODULE,
155 };
156 
157 /* function prototypes */
158 
159 static int mtty_trigger_interrupt(uuid_le uuid);
160 
161 /* Helper functions */
162 static struct mdev_state *find_mdev_state_by_uuid(uuid_le uuid)
163 {
164 	struct mdev_state *mds;
165 
166 	list_for_each_entry(mds, &mdev_devices_list, next) {
167 		if (uuid_le_cmp(mdev_uuid(mds->mdev), uuid) == 0)
168 			return mds;
169 	}
170 
171 	return NULL;
172 }
173 
174 void dump_buffer(u8 *buf, uint32_t count)
175 {
176 #if defined(DEBUG)
177 	int i;
178 
179 	pr_info("Buffer:\n");
180 	for (i = 0; i < count; i++) {
181 		pr_info("%2x ", *(buf + i));
182 		if ((i + 1) % 16 == 0)
183 			pr_info("\n");
184 	}
185 #endif
186 }
187 
188 static void mtty_create_config_space(struct mdev_state *mdev_state)
189 {
190 	/* PCI dev ID */
191 	STORE_LE32((u32 *) &mdev_state->vconfig[0x0], 0x32534348);
192 
193 	/* Control: I/O+, Mem-, BusMaster- */
194 	STORE_LE16((u16 *) &mdev_state->vconfig[0x4], 0x0001);
195 
196 	/* Status: capabilities list absent */
197 	STORE_LE16((u16 *) &mdev_state->vconfig[0x6], 0x0200);
198 
199 	/* Rev ID */
200 	mdev_state->vconfig[0x8] =  0x10;
201 
202 	/* programming interface class : 16550-compatible serial controller */
203 	mdev_state->vconfig[0x9] =  0x02;
204 
205 	/* Sub class : 00 */
206 	mdev_state->vconfig[0xa] =  0x00;
207 
208 	/* Base class : Simple Communication controllers */
209 	mdev_state->vconfig[0xb] =  0x07;
210 
211 	/* base address registers */
212 	/* BAR0: IO space */
213 	STORE_LE32((u32 *) &mdev_state->vconfig[0x10], 0x000001);
214 	mdev_state->bar_mask[0] = ~(MTTY_IO_BAR_SIZE) + 1;
215 
216 	if (mdev_state->nr_ports == 2) {
217 		/* BAR1: IO space */
218 		STORE_LE32((u32 *) &mdev_state->vconfig[0x14], 0x000001);
219 		mdev_state->bar_mask[1] = ~(MTTY_IO_BAR_SIZE) + 1;
220 	}
221 
222 	/* Subsystem ID */
223 	STORE_LE32((u32 *) &mdev_state->vconfig[0x2c], 0x32534348);
224 
225 	mdev_state->vconfig[0x34] =  0x00;   /* Cap Ptr */
226 	mdev_state->vconfig[0x3d] =  0x01;   /* interrupt pin (INTA#) */
227 
228 	/* Vendor specific data */
229 	mdev_state->vconfig[0x40] =  0x23;
230 	mdev_state->vconfig[0x43] =  0x80;
231 	mdev_state->vconfig[0x44] =  0x23;
232 	mdev_state->vconfig[0x48] =  0x23;
233 	mdev_state->vconfig[0x4c] =  0x23;
234 
235 	mdev_state->vconfig[0x60] =  0x50;
236 	mdev_state->vconfig[0x61] =  0x43;
237 	mdev_state->vconfig[0x62] =  0x49;
238 	mdev_state->vconfig[0x63] =  0x20;
239 	mdev_state->vconfig[0x64] =  0x53;
240 	mdev_state->vconfig[0x65] =  0x65;
241 	mdev_state->vconfig[0x66] =  0x72;
242 	mdev_state->vconfig[0x67] =  0x69;
243 	mdev_state->vconfig[0x68] =  0x61;
244 	mdev_state->vconfig[0x69] =  0x6c;
245 	mdev_state->vconfig[0x6a] =  0x2f;
246 	mdev_state->vconfig[0x6b] =  0x55;
247 	mdev_state->vconfig[0x6c] =  0x41;
248 	mdev_state->vconfig[0x6d] =  0x52;
249 	mdev_state->vconfig[0x6e] =  0x54;
250 }
251 
252 static void handle_pci_cfg_write(struct mdev_state *mdev_state, u16 offset,
253 				 u8 *buf, u32 count)
254 {
255 	u32 cfg_addr, bar_mask, bar_index = 0;
256 
257 	switch (offset) {
258 	case 0x04: /* device control */
259 	case 0x06: /* device status */
260 		/* do nothing */
261 		break;
262 	case 0x3c:  /* interrupt line */
263 		mdev_state->vconfig[0x3c] = buf[0];
264 		break;
265 	case 0x3d:
266 		/*
267 		 * Interrupt Pin is hardwired to INTA.
268 		 * This field is write protected by hardware
269 		 */
270 		break;
271 	case 0x10:  /* BAR0 */
272 	case 0x14:  /* BAR1 */
273 		if (offset == 0x10)
274 			bar_index = 0;
275 		else if (offset == 0x14)
276 			bar_index = 1;
277 
278 		if ((mdev_state->nr_ports == 1) && (bar_index == 1)) {
279 			STORE_LE32(&mdev_state->vconfig[offset], 0);
280 			break;
281 		}
282 
283 		cfg_addr = *(u32 *)buf;
284 		pr_info("BAR%d addr 0x%x\n", bar_index, cfg_addr);
285 
286 		if (cfg_addr == 0xffffffff) {
287 			bar_mask = mdev_state->bar_mask[bar_index];
288 			cfg_addr = (cfg_addr & bar_mask);
289 		}
290 
291 		cfg_addr |= (mdev_state->vconfig[offset] & 0x3ul);
292 		STORE_LE32(&mdev_state->vconfig[offset], cfg_addr);
293 		break;
294 	case 0x18:  /* BAR2 */
295 	case 0x1c:  /* BAR3 */
296 	case 0x20:  /* BAR4 */
297 		STORE_LE32(&mdev_state->vconfig[offset], 0);
298 		break;
299 	default:
300 		pr_info("PCI config write @0x%x of %d bytes not handled\n",
301 			offset, count);
302 		break;
303 	}
304 }
305 
306 static void handle_bar_write(unsigned int index, struct mdev_state *mdev_state,
307 				u16 offset, u8 *buf, u32 count)
308 {
309 	u8 data = *buf;
310 
311 	/* Handle data written by guest */
312 	switch (offset) {
313 	case UART_TX:
314 		/* if DLAB set, data is LSB of divisor */
315 		if (mdev_state->s[index].dlab) {
316 			mdev_state->s[index].divisor |= data;
317 			break;
318 		}
319 
320 		mutex_lock(&mdev_state->rxtx_lock);
321 
322 		/* save in TX buffer */
323 		if (mdev_state->s[index].rxtx.count <
324 				mdev_state->s[index].max_fifo_size) {
325 			mdev_state->s[index].rxtx.fifo[
326 					mdev_state->s[index].rxtx.head] = data;
327 			mdev_state->s[index].rxtx.count++;
328 			CIRCULAR_BUF_INC_IDX(mdev_state->s[index].rxtx.head);
329 			mdev_state->s[index].overrun = false;
330 
331 			/*
332 			 * Trigger interrupt if receive data interrupt is
333 			 * enabled and fifo reached trigger level
334 			 */
335 			if ((mdev_state->s[index].uart_reg[UART_IER] &
336 						UART_IER_RDI) &&
337 			   (mdev_state->s[index].rxtx.count ==
338 				    mdev_state->s[index].intr_trigger_level)) {
339 				/* trigger interrupt */
340 #if defined(DEBUG_INTR)
341 				pr_err("Serial port %d: Fifo level trigger\n",
342 					index);
343 #endif
344 				mtty_trigger_interrupt(
345 						mdev_uuid(mdev_state->mdev));
346 			}
347 		} else {
348 #if defined(DEBUG_INTR)
349 			pr_err("Serial port %d: Buffer Overflow\n", index);
350 #endif
351 			mdev_state->s[index].overrun = true;
352 
353 			/*
354 			 * Trigger interrupt if receiver line status interrupt
355 			 * is enabled
356 			 */
357 			if (mdev_state->s[index].uart_reg[UART_IER] &
358 								UART_IER_RLSI)
359 				mtty_trigger_interrupt(
360 						mdev_uuid(mdev_state->mdev));
361 		}
362 		mutex_unlock(&mdev_state->rxtx_lock);
363 		break;
364 
365 	case UART_IER:
366 		/* if DLAB set, data is MSB of divisor */
367 		if (mdev_state->s[index].dlab)
368 			mdev_state->s[index].divisor |= (u16)data << 8;
369 		else {
370 			mdev_state->s[index].uart_reg[offset] = data;
371 			mutex_lock(&mdev_state->rxtx_lock);
372 			if ((data & UART_IER_THRI) &&
373 			    (mdev_state->s[index].rxtx.head ==
374 					mdev_state->s[index].rxtx.tail)) {
375 #if defined(DEBUG_INTR)
376 				pr_err("Serial port %d: IER_THRI write\n",
377 					index);
378 #endif
379 				mtty_trigger_interrupt(
380 						mdev_uuid(mdev_state->mdev));
381 			}
382 
383 			mutex_unlock(&mdev_state->rxtx_lock);
384 		}
385 
386 		break;
387 
388 	case UART_FCR:
389 		mdev_state->s[index].fcr = data;
390 
391 		mutex_lock(&mdev_state->rxtx_lock);
392 		if (data & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT)) {
393 			/* clear loop back FIFO */
394 			mdev_state->s[index].rxtx.count = 0;
395 			mdev_state->s[index].rxtx.head = 0;
396 			mdev_state->s[index].rxtx.tail = 0;
397 		}
398 		mutex_unlock(&mdev_state->rxtx_lock);
399 
400 		switch (data & UART_FCR_TRIGGER_MASK) {
401 		case UART_FCR_TRIGGER_1:
402 			mdev_state->s[index].intr_trigger_level = 1;
403 			break;
404 
405 		case UART_FCR_TRIGGER_4:
406 			mdev_state->s[index].intr_trigger_level = 4;
407 			break;
408 
409 		case UART_FCR_TRIGGER_8:
410 			mdev_state->s[index].intr_trigger_level = 8;
411 			break;
412 
413 		case UART_FCR_TRIGGER_14:
414 			mdev_state->s[index].intr_trigger_level = 14;
415 			break;
416 		}
417 
418 		/*
419 		 * Set trigger level to 1 otherwise or  implement timer with
420 		 * timeout of 4 characters and on expiring that timer set
421 		 * Recevice data timeout in IIR register
422 		 */
423 		mdev_state->s[index].intr_trigger_level = 1;
424 		if (data & UART_FCR_ENABLE_FIFO)
425 			mdev_state->s[index].max_fifo_size = MAX_FIFO_SIZE;
426 		else {
427 			mdev_state->s[index].max_fifo_size = 1;
428 			mdev_state->s[index].intr_trigger_level = 1;
429 		}
430 
431 		break;
432 
433 	case UART_LCR:
434 		if (data & UART_LCR_DLAB) {
435 			mdev_state->s[index].dlab = true;
436 			mdev_state->s[index].divisor = 0;
437 		} else
438 			mdev_state->s[index].dlab = false;
439 
440 		mdev_state->s[index].uart_reg[offset] = data;
441 		break;
442 
443 	case UART_MCR:
444 		mdev_state->s[index].uart_reg[offset] = data;
445 
446 		if ((mdev_state->s[index].uart_reg[UART_IER] & UART_IER_MSI) &&
447 				(data & UART_MCR_OUT2)) {
448 #if defined(DEBUG_INTR)
449 			pr_err("Serial port %d: MCR_OUT2 write\n", index);
450 #endif
451 			mtty_trigger_interrupt(mdev_uuid(mdev_state->mdev));
452 		}
453 
454 		if ((mdev_state->s[index].uart_reg[UART_IER] & UART_IER_MSI) &&
455 				(data & (UART_MCR_RTS | UART_MCR_DTR))) {
456 #if defined(DEBUG_INTR)
457 			pr_err("Serial port %d: MCR RTS/DTR write\n", index);
458 #endif
459 			mtty_trigger_interrupt(mdev_uuid(mdev_state->mdev));
460 		}
461 		break;
462 
463 	case UART_LSR:
464 	case UART_MSR:
465 		/* do nothing */
466 		break;
467 
468 	case UART_SCR:
469 		mdev_state->s[index].uart_reg[offset] = data;
470 		break;
471 
472 	default:
473 		break;
474 	}
475 }
476 
477 static void handle_bar_read(unsigned int index, struct mdev_state *mdev_state,
478 			    u16 offset, u8 *buf, u32 count)
479 {
480 	/* Handle read requests by guest */
481 	switch (offset) {
482 	case UART_RX:
483 		/* if DLAB set, data is LSB of divisor */
484 		if (mdev_state->s[index].dlab) {
485 			*buf  = (u8)mdev_state->s[index].divisor;
486 			break;
487 		}
488 
489 		mutex_lock(&mdev_state->rxtx_lock);
490 		/* return data in tx buffer */
491 		if (mdev_state->s[index].rxtx.head !=
492 				 mdev_state->s[index].rxtx.tail) {
493 			*buf = mdev_state->s[index].rxtx.fifo[
494 						mdev_state->s[index].rxtx.tail];
495 			mdev_state->s[index].rxtx.count--;
496 			CIRCULAR_BUF_INC_IDX(mdev_state->s[index].rxtx.tail);
497 		}
498 
499 		if (mdev_state->s[index].rxtx.head ==
500 				mdev_state->s[index].rxtx.tail) {
501 		/*
502 		 *  Trigger interrupt if tx buffer empty interrupt is
503 		 *  enabled and fifo is empty
504 		 */
505 #if defined(DEBUG_INTR)
506 			pr_err("Serial port %d: Buffer Empty\n", index);
507 #endif
508 			if (mdev_state->s[index].uart_reg[UART_IER] &
509 							 UART_IER_THRI)
510 				mtty_trigger_interrupt(
511 					mdev_uuid(mdev_state->mdev));
512 		}
513 		mutex_unlock(&mdev_state->rxtx_lock);
514 
515 		break;
516 
517 	case UART_IER:
518 		if (mdev_state->s[index].dlab) {
519 			*buf = (u8)(mdev_state->s[index].divisor >> 8);
520 			break;
521 		}
522 		*buf = mdev_state->s[index].uart_reg[offset] & 0x0f;
523 		break;
524 
525 	case UART_IIR:
526 	{
527 		u8 ier = mdev_state->s[index].uart_reg[UART_IER];
528 		*buf = 0;
529 
530 		mutex_lock(&mdev_state->rxtx_lock);
531 		/* Interrupt priority 1: Parity, overrun, framing or break */
532 		if ((ier & UART_IER_RLSI) && mdev_state->s[index].overrun)
533 			*buf |= UART_IIR_RLSI;
534 
535 		/* Interrupt priority 2: Fifo trigger level reached */
536 		if ((ier & UART_IER_RDI) &&
537 		    (mdev_state->s[index].rxtx.count >=
538 		      mdev_state->s[index].intr_trigger_level))
539 			*buf |= UART_IIR_RDI;
540 
541 		/* Interrupt priotiry 3: transmitter holding register empty */
542 		if ((ier & UART_IER_THRI) &&
543 		    (mdev_state->s[index].rxtx.head ==
544 				mdev_state->s[index].rxtx.tail))
545 			*buf |= UART_IIR_THRI;
546 
547 		/* Interrupt priotiry 4: Modem status: CTS, DSR, RI or DCD  */
548 		if ((ier & UART_IER_MSI) &&
549 		    (mdev_state->s[index].uart_reg[UART_MCR] &
550 				 (UART_MCR_RTS | UART_MCR_DTR)))
551 			*buf |= UART_IIR_MSI;
552 
553 		/* bit0: 0=> interrupt pending, 1=> no interrupt is pending */
554 		if (*buf == 0)
555 			*buf = UART_IIR_NO_INT;
556 
557 		/* set bit 6 & 7 to be 16550 compatible */
558 		*buf |= 0xC0;
559 		mutex_unlock(&mdev_state->rxtx_lock);
560 	}
561 	break;
562 
563 	case UART_LCR:
564 	case UART_MCR:
565 		*buf = mdev_state->s[index].uart_reg[offset];
566 		break;
567 
568 	case UART_LSR:
569 	{
570 		u8 lsr = 0;
571 
572 		mutex_lock(&mdev_state->rxtx_lock);
573 		/* atleast one char in FIFO */
574 		if (mdev_state->s[index].rxtx.head !=
575 				 mdev_state->s[index].rxtx.tail)
576 			lsr |= UART_LSR_DR;
577 
578 		/* if FIFO overrun */
579 		if (mdev_state->s[index].overrun)
580 			lsr |= UART_LSR_OE;
581 
582 		/* transmit FIFO empty and tramsitter empty */
583 		if (mdev_state->s[index].rxtx.head ==
584 				 mdev_state->s[index].rxtx.tail)
585 			lsr |= UART_LSR_TEMT | UART_LSR_THRE;
586 
587 		mutex_unlock(&mdev_state->rxtx_lock);
588 		*buf = lsr;
589 		break;
590 	}
591 	case UART_MSR:
592 		*buf = UART_MSR_DSR | UART_MSR_DDSR | UART_MSR_DCD;
593 
594 		mutex_lock(&mdev_state->rxtx_lock);
595 		/* if AFE is 1 and FIFO have space, set CTS bit */
596 		if (mdev_state->s[index].uart_reg[UART_MCR] &
597 						 UART_MCR_AFE) {
598 			if (mdev_state->s[index].rxtx.count <
599 					mdev_state->s[index].max_fifo_size)
600 				*buf |= UART_MSR_CTS | UART_MSR_DCTS;
601 		} else
602 			*buf |= UART_MSR_CTS | UART_MSR_DCTS;
603 		mutex_unlock(&mdev_state->rxtx_lock);
604 
605 		break;
606 
607 	case UART_SCR:
608 		*buf = mdev_state->s[index].uart_reg[offset];
609 		break;
610 
611 	default:
612 		break;
613 	}
614 }
615 
616 static void mdev_read_base(struct mdev_state *mdev_state)
617 {
618 	int index, pos;
619 	u32 start_lo, start_hi;
620 	u32 mem_type;
621 
622 	pos = PCI_BASE_ADDRESS_0;
623 
624 	for (index = 0; index <= VFIO_PCI_BAR5_REGION_INDEX; index++) {
625 
626 		if (!mdev_state->region_info[index].size)
627 			continue;
628 
629 		start_lo = (*(u32 *)(mdev_state->vconfig + pos)) &
630 			PCI_BASE_ADDRESS_MEM_MASK;
631 		mem_type = (*(u32 *)(mdev_state->vconfig + pos)) &
632 			PCI_BASE_ADDRESS_MEM_TYPE_MASK;
633 
634 		switch (mem_type) {
635 		case PCI_BASE_ADDRESS_MEM_TYPE_64:
636 			start_hi = (*(u32 *)(mdev_state->vconfig + pos + 4));
637 			pos += 4;
638 			break;
639 		case PCI_BASE_ADDRESS_MEM_TYPE_32:
640 		case PCI_BASE_ADDRESS_MEM_TYPE_1M:
641 			/* 1M mem BAR treated as 32-bit BAR */
642 		default:
643 			/* mem unknown type treated as 32-bit BAR */
644 			start_hi = 0;
645 			break;
646 		}
647 		pos += 4;
648 		mdev_state->region_info[index].start = ((u64)start_hi << 32) |
649 							start_lo;
650 	}
651 }
652 
653 static ssize_t mdev_access(struct mdev_device *mdev, u8 *buf, size_t count,
654 			   loff_t pos, bool is_write)
655 {
656 	struct mdev_state *mdev_state;
657 	unsigned int index;
658 	loff_t offset;
659 	int ret = 0;
660 
661 	if (!mdev || !buf)
662 		return -EINVAL;
663 
664 	mdev_state = mdev_get_drvdata(mdev);
665 	if (!mdev_state) {
666 		pr_err("%s mdev_state not found\n", __func__);
667 		return -EINVAL;
668 	}
669 
670 	mutex_lock(&mdev_state->ops_lock);
671 
672 	index = MTTY_VFIO_PCI_OFFSET_TO_INDEX(pos);
673 	offset = pos & MTTY_VFIO_PCI_OFFSET_MASK;
674 	switch (index) {
675 	case VFIO_PCI_CONFIG_REGION_INDEX:
676 
677 #if defined(DEBUG)
678 		pr_info("%s: PCI config space %s at offset 0x%llx\n",
679 			 __func__, is_write ? "write" : "read", offset);
680 #endif
681 		if (is_write) {
682 			dump_buffer(buf, count);
683 			handle_pci_cfg_write(mdev_state, offset, buf, count);
684 		} else {
685 			memcpy(buf, (mdev_state->vconfig + offset), count);
686 			dump_buffer(buf, count);
687 		}
688 
689 		break;
690 
691 	case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
692 		if (!mdev_state->region_info[index].start)
693 			mdev_read_base(mdev_state);
694 
695 		if (is_write) {
696 			dump_buffer(buf, count);
697 
698 #if defined(DEBUG_REGS)
699 			pr_info("%s: BAR%d  WR @0x%llx %s val:0x%02x dlab:%d\n",
700 				__func__, index, offset, wr_reg[offset],
701 				*buf, mdev_state->s[index].dlab);
702 #endif
703 			handle_bar_write(index, mdev_state, offset, buf, count);
704 		} else {
705 			handle_bar_read(index, mdev_state, offset, buf, count);
706 			dump_buffer(buf, count);
707 
708 #if defined(DEBUG_REGS)
709 			pr_info("%s: BAR%d  RD @0x%llx %s val:0x%02x dlab:%d\n",
710 				__func__, index, offset, rd_reg[offset],
711 				*buf, mdev_state->s[index].dlab);
712 #endif
713 		}
714 		break;
715 
716 	default:
717 		ret = -1;
718 		goto accessfailed;
719 	}
720 
721 	ret = count;
722 
723 
724 accessfailed:
725 	mutex_unlock(&mdev_state->ops_lock);
726 
727 	return ret;
728 }
729 
730 int mtty_create(struct kobject *kobj, struct mdev_device *mdev)
731 {
732 	struct mdev_state *mdev_state;
733 	char name[MTTY_STRING_LEN];
734 	int nr_ports = 0, i;
735 
736 	if (!mdev)
737 		return -EINVAL;
738 
739 	for (i = 0; i < 2; i++) {
740 		snprintf(name, MTTY_STRING_LEN, "%s-%d",
741 			dev_driver_string(mdev_parent_dev(mdev)), i + 1);
742 		if (!strcmp(kobj->name, name)) {
743 			nr_ports = i + 1;
744 			break;
745 		}
746 	}
747 
748 	if (!nr_ports)
749 		return -EINVAL;
750 
751 	mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL);
752 	if (mdev_state == NULL)
753 		return -ENOMEM;
754 
755 	mdev_state->nr_ports = nr_ports;
756 	mdev_state->irq_index = -1;
757 	mdev_state->s[0].max_fifo_size = MAX_FIFO_SIZE;
758 	mdev_state->s[1].max_fifo_size = MAX_FIFO_SIZE;
759 	mutex_init(&mdev_state->rxtx_lock);
760 	mdev_state->vconfig = kzalloc(MTTY_CONFIG_SPACE_SIZE, GFP_KERNEL);
761 
762 	if (mdev_state->vconfig == NULL) {
763 		kfree(mdev_state);
764 		return -ENOMEM;
765 	}
766 
767 	mutex_init(&mdev_state->ops_lock);
768 	mdev_state->mdev = mdev;
769 	mdev_set_drvdata(mdev, mdev_state);
770 
771 	mtty_create_config_space(mdev_state);
772 
773 	mutex_lock(&mdev_list_lock);
774 	list_add(&mdev_state->next, &mdev_devices_list);
775 	mutex_unlock(&mdev_list_lock);
776 
777 	return 0;
778 }
779 
780 int mtty_remove(struct mdev_device *mdev)
781 {
782 	struct mdev_state *mds, *tmp_mds;
783 	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
784 	int ret = -EINVAL;
785 
786 	mutex_lock(&mdev_list_lock);
787 	list_for_each_entry_safe(mds, tmp_mds, &mdev_devices_list, next) {
788 		if (mdev_state == mds) {
789 			list_del(&mdev_state->next);
790 			mdev_set_drvdata(mdev, NULL);
791 			kfree(mdev_state->vconfig);
792 			kfree(mdev_state);
793 			ret = 0;
794 			break;
795 		}
796 	}
797 	mutex_unlock(&mdev_list_lock);
798 
799 	return ret;
800 }
801 
802 int mtty_reset(struct mdev_device *mdev)
803 {
804 	struct mdev_state *mdev_state;
805 
806 	if (!mdev)
807 		return -EINVAL;
808 
809 	mdev_state = mdev_get_drvdata(mdev);
810 	if (!mdev_state)
811 		return -EINVAL;
812 
813 	pr_info("%s: called\n", __func__);
814 
815 	return 0;
816 }
817 
818 ssize_t mtty_read(struct mdev_device *mdev, char __user *buf, size_t count,
819 		  loff_t *ppos)
820 {
821 	unsigned int done = 0;
822 	int ret;
823 
824 	while (count) {
825 		size_t filled;
826 
827 		if (count >= 4 && !(*ppos % 4)) {
828 			u32 val;
829 
830 			ret =  mdev_access(mdev, (u8 *)&val, sizeof(val),
831 					   *ppos, false);
832 			if (ret <= 0)
833 				goto read_err;
834 
835 			if (copy_to_user(buf, &val, sizeof(val)))
836 				goto read_err;
837 
838 			filled = 4;
839 		} else if (count >= 2 && !(*ppos % 2)) {
840 			u16 val;
841 
842 			ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
843 					  *ppos, false);
844 			if (ret <= 0)
845 				goto read_err;
846 
847 			if (copy_to_user(buf, &val, sizeof(val)))
848 				goto read_err;
849 
850 			filled = 2;
851 		} else {
852 			u8 val;
853 
854 			ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
855 					  *ppos, false);
856 			if (ret <= 0)
857 				goto read_err;
858 
859 			if (copy_to_user(buf, &val, sizeof(val)))
860 				goto read_err;
861 
862 			filled = 1;
863 		}
864 
865 		count -= filled;
866 		done += filled;
867 		*ppos += filled;
868 		buf += filled;
869 	}
870 
871 	return done;
872 
873 read_err:
874 	return -EFAULT;
875 }
876 
877 ssize_t mtty_write(struct mdev_device *mdev, const char __user *buf,
878 		   size_t count, loff_t *ppos)
879 {
880 	unsigned int done = 0;
881 	int ret;
882 
883 	while (count) {
884 		size_t filled;
885 
886 		if (count >= 4 && !(*ppos % 4)) {
887 			u32 val;
888 
889 			if (copy_from_user(&val, buf, sizeof(val)))
890 				goto write_err;
891 
892 			ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
893 					  *ppos, true);
894 			if (ret <= 0)
895 				goto write_err;
896 
897 			filled = 4;
898 		} else if (count >= 2 && !(*ppos % 2)) {
899 			u16 val;
900 
901 			if (copy_from_user(&val, buf, sizeof(val)))
902 				goto write_err;
903 
904 			ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
905 					  *ppos, true);
906 			if (ret <= 0)
907 				goto write_err;
908 
909 			filled = 2;
910 		} else {
911 			u8 val;
912 
913 			if (copy_from_user(&val, buf, sizeof(val)))
914 				goto write_err;
915 
916 			ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
917 					  *ppos, true);
918 			if (ret <= 0)
919 				goto write_err;
920 
921 			filled = 1;
922 		}
923 		count -= filled;
924 		done += filled;
925 		*ppos += filled;
926 		buf += filled;
927 	}
928 
929 	return done;
930 write_err:
931 	return -EFAULT;
932 }
933 
934 static int mtty_set_irqs(struct mdev_device *mdev, uint32_t flags,
935 			 unsigned int index, unsigned int start,
936 			 unsigned int count, void *data)
937 {
938 	int ret = 0;
939 	struct mdev_state *mdev_state;
940 
941 	if (!mdev)
942 		return -EINVAL;
943 
944 	mdev_state = mdev_get_drvdata(mdev);
945 	if (!mdev_state)
946 		return -EINVAL;
947 
948 	mutex_lock(&mdev_state->ops_lock);
949 	switch (index) {
950 	case VFIO_PCI_INTX_IRQ_INDEX:
951 		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
952 		case VFIO_IRQ_SET_ACTION_MASK:
953 		case VFIO_IRQ_SET_ACTION_UNMASK:
954 			break;
955 		case VFIO_IRQ_SET_ACTION_TRIGGER:
956 		{
957 			if (flags & VFIO_IRQ_SET_DATA_NONE) {
958 				pr_info("%s: disable INTx\n", __func__);
959 				if (mdev_state->intx_evtfd)
960 					eventfd_ctx_put(mdev_state->intx_evtfd);
961 				break;
962 			}
963 
964 			if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
965 				int fd = *(int *)data;
966 
967 				if (fd > 0) {
968 					struct eventfd_ctx *evt;
969 
970 					evt = eventfd_ctx_fdget(fd);
971 					if (IS_ERR(evt)) {
972 						ret = PTR_ERR(evt);
973 						break;
974 					}
975 					mdev_state->intx_evtfd = evt;
976 					mdev_state->irq_fd = fd;
977 					mdev_state->irq_index = index;
978 					break;
979 				}
980 			}
981 			break;
982 		}
983 		}
984 		break;
985 	case VFIO_PCI_MSI_IRQ_INDEX:
986 		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
987 		case VFIO_IRQ_SET_ACTION_MASK:
988 		case VFIO_IRQ_SET_ACTION_UNMASK:
989 			break;
990 		case VFIO_IRQ_SET_ACTION_TRIGGER:
991 			if (flags & VFIO_IRQ_SET_DATA_NONE) {
992 				if (mdev_state->msi_evtfd)
993 					eventfd_ctx_put(mdev_state->msi_evtfd);
994 				pr_info("%s: disable MSI\n", __func__);
995 				mdev_state->irq_index = VFIO_PCI_INTX_IRQ_INDEX;
996 				break;
997 			}
998 			if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
999 				int fd = *(int *)data;
1000 				struct eventfd_ctx *evt;
1001 
1002 				if (fd <= 0)
1003 					break;
1004 
1005 				if (mdev_state->msi_evtfd)
1006 					break;
1007 
1008 				evt = eventfd_ctx_fdget(fd);
1009 				if (IS_ERR(evt)) {
1010 					ret = PTR_ERR(evt);
1011 					break;
1012 				}
1013 				mdev_state->msi_evtfd = evt;
1014 				mdev_state->irq_fd = fd;
1015 				mdev_state->irq_index = index;
1016 			}
1017 			break;
1018 	}
1019 	break;
1020 	case VFIO_PCI_MSIX_IRQ_INDEX:
1021 		pr_info("%s: MSIX_IRQ\n", __func__);
1022 		break;
1023 	case VFIO_PCI_ERR_IRQ_INDEX:
1024 		pr_info("%s: ERR_IRQ\n", __func__);
1025 		break;
1026 	case VFIO_PCI_REQ_IRQ_INDEX:
1027 		pr_info("%s: REQ_IRQ\n", __func__);
1028 		break;
1029 	}
1030 
1031 	mutex_unlock(&mdev_state->ops_lock);
1032 	return ret;
1033 }
1034 
1035 static int mtty_trigger_interrupt(uuid_le uuid)
1036 {
1037 	int ret = -1;
1038 	struct mdev_state *mdev_state;
1039 
1040 	mdev_state = find_mdev_state_by_uuid(uuid);
1041 
1042 	if (!mdev_state) {
1043 		pr_info("%s: mdev not found\n", __func__);
1044 		return -EINVAL;
1045 	}
1046 
1047 	if ((mdev_state->irq_index == VFIO_PCI_MSI_IRQ_INDEX) &&
1048 	    (!mdev_state->msi_evtfd))
1049 		return -EINVAL;
1050 	else if ((mdev_state->irq_index == VFIO_PCI_INTX_IRQ_INDEX) &&
1051 		 (!mdev_state->intx_evtfd)) {
1052 		pr_info("%s: Intr eventfd not found\n", __func__);
1053 		return -EINVAL;
1054 	}
1055 
1056 	if (mdev_state->irq_index == VFIO_PCI_MSI_IRQ_INDEX)
1057 		ret = eventfd_signal(mdev_state->msi_evtfd, 1);
1058 	else
1059 		ret = eventfd_signal(mdev_state->intx_evtfd, 1);
1060 
1061 #if defined(DEBUG_INTR)
1062 	pr_info("Intx triggered\n");
1063 #endif
1064 	if (ret != 1)
1065 		pr_err("%s: eventfd signal failed (%d)\n", __func__, ret);
1066 
1067 	return ret;
1068 }
1069 
1070 int mtty_get_region_info(struct mdev_device *mdev,
1071 			 struct vfio_region_info *region_info,
1072 			 u16 *cap_type_id, void **cap_type)
1073 {
1074 	unsigned int size = 0;
1075 	struct mdev_state *mdev_state;
1076 	u32 bar_index;
1077 
1078 	if (!mdev)
1079 		return -EINVAL;
1080 
1081 	mdev_state = mdev_get_drvdata(mdev);
1082 	if (!mdev_state)
1083 		return -EINVAL;
1084 
1085 	bar_index = region_info->index;
1086 	if (bar_index >= VFIO_PCI_NUM_REGIONS)
1087 		return -EINVAL;
1088 
1089 	mutex_lock(&mdev_state->ops_lock);
1090 
1091 	switch (bar_index) {
1092 	case VFIO_PCI_CONFIG_REGION_INDEX:
1093 		size = MTTY_CONFIG_SPACE_SIZE;
1094 		break;
1095 	case VFIO_PCI_BAR0_REGION_INDEX:
1096 		size = MTTY_IO_BAR_SIZE;
1097 		break;
1098 	case VFIO_PCI_BAR1_REGION_INDEX:
1099 		if (mdev_state->nr_ports == 2)
1100 			size = MTTY_IO_BAR_SIZE;
1101 		break;
1102 	default:
1103 		size = 0;
1104 		break;
1105 	}
1106 
1107 	mdev_state->region_info[bar_index].size = size;
1108 	mdev_state->region_info[bar_index].vfio_offset =
1109 		MTTY_VFIO_PCI_INDEX_TO_OFFSET(bar_index);
1110 
1111 	region_info->size = size;
1112 	region_info->offset = MTTY_VFIO_PCI_INDEX_TO_OFFSET(bar_index);
1113 	region_info->flags = VFIO_REGION_INFO_FLAG_READ |
1114 		VFIO_REGION_INFO_FLAG_WRITE;
1115 	mutex_unlock(&mdev_state->ops_lock);
1116 	return 0;
1117 }
1118 
1119 int mtty_get_irq_info(struct mdev_device *mdev, struct vfio_irq_info *irq_info)
1120 {
1121 	switch (irq_info->index) {
1122 	case VFIO_PCI_INTX_IRQ_INDEX:
1123 	case VFIO_PCI_MSI_IRQ_INDEX:
1124 	case VFIO_PCI_REQ_IRQ_INDEX:
1125 		break;
1126 
1127 	default:
1128 		return -EINVAL;
1129 	}
1130 
1131 	irq_info->flags = VFIO_IRQ_INFO_EVENTFD;
1132 	irq_info->count = 1;
1133 
1134 	if (irq_info->index == VFIO_PCI_INTX_IRQ_INDEX)
1135 		irq_info->flags |= (VFIO_IRQ_INFO_MASKABLE |
1136 				VFIO_IRQ_INFO_AUTOMASKED);
1137 	else
1138 		irq_info->flags |= VFIO_IRQ_INFO_NORESIZE;
1139 
1140 	return 0;
1141 }
1142 
1143 int mtty_get_device_info(struct mdev_device *mdev,
1144 			 struct vfio_device_info *dev_info)
1145 {
1146 	dev_info->flags = VFIO_DEVICE_FLAGS_PCI;
1147 	dev_info->num_regions = VFIO_PCI_NUM_REGIONS;
1148 	dev_info->num_irqs = VFIO_PCI_NUM_IRQS;
1149 
1150 	return 0;
1151 }
1152 
1153 static long mtty_ioctl(struct mdev_device *mdev, unsigned int cmd,
1154 			unsigned long arg)
1155 {
1156 	int ret = 0;
1157 	unsigned long minsz;
1158 	struct mdev_state *mdev_state;
1159 
1160 	if (!mdev)
1161 		return -EINVAL;
1162 
1163 	mdev_state = mdev_get_drvdata(mdev);
1164 	if (!mdev_state)
1165 		return -ENODEV;
1166 
1167 	switch (cmd) {
1168 	case VFIO_DEVICE_GET_INFO:
1169 	{
1170 		struct vfio_device_info info;
1171 
1172 		minsz = offsetofend(struct vfio_device_info, num_irqs);
1173 
1174 		if (copy_from_user(&info, (void __user *)arg, minsz))
1175 			return -EFAULT;
1176 
1177 		if (info.argsz < minsz)
1178 			return -EINVAL;
1179 
1180 		ret = mtty_get_device_info(mdev, &info);
1181 		if (ret)
1182 			return ret;
1183 
1184 		memcpy(&mdev_state->dev_info, &info, sizeof(info));
1185 
1186 		if (copy_to_user((void __user *)arg, &info, minsz))
1187 			return -EFAULT;
1188 
1189 		return 0;
1190 	}
1191 	case VFIO_DEVICE_GET_REGION_INFO:
1192 	{
1193 		struct vfio_region_info info;
1194 		u16 cap_type_id = 0;
1195 		void *cap_type = NULL;
1196 
1197 		minsz = offsetofend(struct vfio_region_info, offset);
1198 
1199 		if (copy_from_user(&info, (void __user *)arg, minsz))
1200 			return -EFAULT;
1201 
1202 		if (info.argsz < minsz)
1203 			return -EINVAL;
1204 
1205 		ret = mtty_get_region_info(mdev, &info, &cap_type_id,
1206 					   &cap_type);
1207 		if (ret)
1208 			return ret;
1209 
1210 		if (copy_to_user((void __user *)arg, &info, minsz))
1211 			return -EFAULT;
1212 
1213 		return 0;
1214 	}
1215 
1216 	case VFIO_DEVICE_GET_IRQ_INFO:
1217 	{
1218 		struct vfio_irq_info info;
1219 
1220 		minsz = offsetofend(struct vfio_irq_info, count);
1221 
1222 		if (copy_from_user(&info, (void __user *)arg, minsz))
1223 			return -EFAULT;
1224 
1225 		if ((info.argsz < minsz) ||
1226 		    (info.index >= mdev_state->dev_info.num_irqs))
1227 			return -EINVAL;
1228 
1229 		ret = mtty_get_irq_info(mdev, &info);
1230 		if (ret)
1231 			return ret;
1232 
1233 		if (copy_to_user((void __user *)arg, &info, minsz))
1234 			return -EFAULT;
1235 
1236 		return 0;
1237 	}
1238 	case VFIO_DEVICE_SET_IRQS:
1239 	{
1240 		struct vfio_irq_set hdr;
1241 		u8 *data = NULL, *ptr = NULL;
1242 		size_t data_size = 0;
1243 
1244 		minsz = offsetofend(struct vfio_irq_set, count);
1245 
1246 		if (copy_from_user(&hdr, (void __user *)arg, minsz))
1247 			return -EFAULT;
1248 
1249 		ret = vfio_set_irqs_validate_and_prepare(&hdr,
1250 						mdev_state->dev_info.num_irqs,
1251 						VFIO_PCI_NUM_IRQS,
1252 						&data_size);
1253 		if (ret)
1254 			return ret;
1255 
1256 		if (data_size) {
1257 			ptr = data = memdup_user((void __user *)(arg + minsz),
1258 						 data_size);
1259 			if (IS_ERR(data))
1260 				return PTR_ERR(data);
1261 		}
1262 
1263 		ret = mtty_set_irqs(mdev, hdr.flags, hdr.index, hdr.start,
1264 				    hdr.count, data);
1265 
1266 		kfree(ptr);
1267 		return ret;
1268 	}
1269 	case VFIO_DEVICE_RESET:
1270 		return mtty_reset(mdev);
1271 	}
1272 	return -ENOTTY;
1273 }
1274 
1275 int mtty_open(struct mdev_device *mdev)
1276 {
1277 	pr_info("%s\n", __func__);
1278 	return 0;
1279 }
1280 
1281 void mtty_close(struct mdev_device *mdev)
1282 {
1283 	pr_info("%s\n", __func__);
1284 }
1285 
1286 static ssize_t
1287 sample_mtty_dev_show(struct device *dev, struct device_attribute *attr,
1288 		     char *buf)
1289 {
1290 	return sprintf(buf, "This is phy device\n");
1291 }
1292 
1293 static DEVICE_ATTR_RO(sample_mtty_dev);
1294 
1295 static struct attribute *mtty_dev_attrs[] = {
1296 	&dev_attr_sample_mtty_dev.attr,
1297 	NULL,
1298 };
1299 
1300 static const struct attribute_group mtty_dev_group = {
1301 	.name  = "mtty_dev",
1302 	.attrs = mtty_dev_attrs,
1303 };
1304 
1305 const struct attribute_group *mtty_dev_groups[] = {
1306 	&mtty_dev_group,
1307 	NULL,
1308 };
1309 
1310 static ssize_t
1311 sample_mdev_dev_show(struct device *dev, struct device_attribute *attr,
1312 		     char *buf)
1313 {
1314 	if (mdev_from_dev(dev))
1315 		return sprintf(buf, "This is MDEV %s\n", dev_name(dev));
1316 
1317 	return sprintf(buf, "\n");
1318 }
1319 
1320 static DEVICE_ATTR_RO(sample_mdev_dev);
1321 
1322 static struct attribute *mdev_dev_attrs[] = {
1323 	&dev_attr_sample_mdev_dev.attr,
1324 	NULL,
1325 };
1326 
1327 static const struct attribute_group mdev_dev_group = {
1328 	.name  = "vendor",
1329 	.attrs = mdev_dev_attrs,
1330 };
1331 
1332 const struct attribute_group *mdev_dev_groups[] = {
1333 	&mdev_dev_group,
1334 	NULL,
1335 };
1336 
1337 static ssize_t
1338 name_show(struct kobject *kobj, struct device *dev, char *buf)
1339 {
1340 	char name[MTTY_STRING_LEN];
1341 	int i;
1342 	const char *name_str[2] = {"Single port serial", "Dual port serial"};
1343 
1344 	for (i = 0; i < 2; i++) {
1345 		snprintf(name, MTTY_STRING_LEN, "%s-%d",
1346 			 dev_driver_string(dev), i + 1);
1347 		if (!strcmp(kobj->name, name))
1348 			return sprintf(buf, "%s\n", name_str[i]);
1349 	}
1350 
1351 	return -EINVAL;
1352 }
1353 
1354 MDEV_TYPE_ATTR_RO(name);
1355 
1356 static ssize_t
1357 available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
1358 {
1359 	char name[MTTY_STRING_LEN];
1360 	int i;
1361 	struct mdev_state *mds;
1362 	int ports = 0, used = 0;
1363 
1364 	for (i = 0; i < 2; i++) {
1365 		snprintf(name, MTTY_STRING_LEN, "%s-%d",
1366 			 dev_driver_string(dev), i + 1);
1367 		if (!strcmp(kobj->name, name)) {
1368 			ports = i + 1;
1369 			break;
1370 		}
1371 	}
1372 
1373 	if (!ports)
1374 		return -EINVAL;
1375 
1376 	list_for_each_entry(mds, &mdev_devices_list, next)
1377 		used += mds->nr_ports;
1378 
1379 	return sprintf(buf, "%d\n", (MAX_MTTYS - used)/ports);
1380 }
1381 
1382 MDEV_TYPE_ATTR_RO(available_instances);
1383 
1384 
1385 static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
1386 			       char *buf)
1387 {
1388 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
1389 }
1390 
1391 MDEV_TYPE_ATTR_RO(device_api);
1392 
1393 static struct attribute *mdev_types_attrs[] = {
1394 	&mdev_type_attr_name.attr,
1395 	&mdev_type_attr_device_api.attr,
1396 	&mdev_type_attr_available_instances.attr,
1397 	NULL,
1398 };
1399 
1400 static struct attribute_group mdev_type_group1 = {
1401 	.name  = "1",
1402 	.attrs = mdev_types_attrs,
1403 };
1404 
1405 static struct attribute_group mdev_type_group2 = {
1406 	.name  = "2",
1407 	.attrs = mdev_types_attrs,
1408 };
1409 
1410 struct attribute_group *mdev_type_groups[] = {
1411 	&mdev_type_group1,
1412 	&mdev_type_group2,
1413 	NULL,
1414 };
1415 
1416 static const struct mdev_parent_ops mdev_fops = {
1417 	.owner                  = THIS_MODULE,
1418 	.dev_attr_groups        = mtty_dev_groups,
1419 	.mdev_attr_groups       = mdev_dev_groups,
1420 	.supported_type_groups  = mdev_type_groups,
1421 	.create                 = mtty_create,
1422 	.remove			= mtty_remove,
1423 	.open                   = mtty_open,
1424 	.release                = mtty_close,
1425 	.read                   = mtty_read,
1426 	.write                  = mtty_write,
1427 	.ioctl		        = mtty_ioctl,
1428 };
1429 
1430 static void mtty_device_release(struct device *dev)
1431 {
1432 	dev_dbg(dev, "mtty: released\n");
1433 }
1434 
1435 static int __init mtty_dev_init(void)
1436 {
1437 	int ret = 0;
1438 
1439 	pr_info("mtty_dev: %s\n", __func__);
1440 
1441 	memset(&mtty_dev, 0, sizeof(mtty_dev));
1442 
1443 	idr_init(&mtty_dev.vd_idr);
1444 
1445 	ret = alloc_chrdev_region(&mtty_dev.vd_devt, 0, MINORMASK, MTTY_NAME);
1446 
1447 	if (ret < 0) {
1448 		pr_err("Error: failed to register mtty_dev, err:%d\n", ret);
1449 		return ret;
1450 	}
1451 
1452 	cdev_init(&mtty_dev.vd_cdev, &vd_fops);
1453 	cdev_add(&mtty_dev.vd_cdev, mtty_dev.vd_devt, MINORMASK);
1454 
1455 	pr_info("major_number:%d\n", MAJOR(mtty_dev.vd_devt));
1456 
1457 	mtty_dev.vd_class = class_create(THIS_MODULE, MTTY_CLASS_NAME);
1458 
1459 	if (IS_ERR(mtty_dev.vd_class)) {
1460 		pr_err("Error: failed to register mtty_dev class\n");
1461 		ret = PTR_ERR(mtty_dev.vd_class);
1462 		goto failed1;
1463 	}
1464 
1465 	mtty_dev.dev.class = mtty_dev.vd_class;
1466 	mtty_dev.dev.release = mtty_device_release;
1467 	dev_set_name(&mtty_dev.dev, "%s", MTTY_NAME);
1468 
1469 	ret = device_register(&mtty_dev.dev);
1470 	if (ret)
1471 		goto failed2;
1472 
1473 	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
1474 	if (ret)
1475 		goto failed3;
1476 
1477 	mutex_init(&mdev_list_lock);
1478 	INIT_LIST_HEAD(&mdev_devices_list);
1479 
1480 	goto all_done;
1481 
1482 failed3:
1483 
1484 	device_unregister(&mtty_dev.dev);
1485 failed2:
1486 	class_destroy(mtty_dev.vd_class);
1487 
1488 failed1:
1489 	cdev_del(&mtty_dev.vd_cdev);
1490 	unregister_chrdev_region(mtty_dev.vd_devt, MINORMASK);
1491 
1492 all_done:
1493 	return ret;
1494 }
1495 
1496 static void __exit mtty_dev_exit(void)
1497 {
1498 	mtty_dev.dev.bus = NULL;
1499 	mdev_unregister_device(&mtty_dev.dev);
1500 
1501 	device_unregister(&mtty_dev.dev);
1502 	idr_destroy(&mtty_dev.vd_idr);
1503 	cdev_del(&mtty_dev.vd_cdev);
1504 	unregister_chrdev_region(mtty_dev.vd_devt, MINORMASK);
1505 	class_destroy(mtty_dev.vd_class);
1506 	mtty_dev.vd_class = NULL;
1507 	pr_info("mtty_dev: Unloaded!\n");
1508 }
1509 
1510 module_init(mtty_dev_init)
1511 module_exit(mtty_dev_exit)
1512 
1513 MODULE_LICENSE("GPL v2");
1514 MODULE_INFO(supported, "Test driver that simulate serial port over PCI");
1515 MODULE_VERSION(VERSION_STRING);
1516 MODULE_AUTHOR(DRIVER_AUTHOR);
1517