gigaset: asyncdata: mark expected switch fall-throughs
[linux/fpc-iii.git] / drivers / platform / goldfish / goldfish_pipe.c
blob2da567540c2daeb7815fd9b559b593f1dc0bf03c
1 /*
2 * Copyright (C) 2012 Intel, Inc.
3 * Copyright (C) 2013 Intel, Inc.
4 * Copyright (C) 2014 Linaro Limited
5 * Copyright (C) 2011-2016 Google, Inc.
7 * This software is licensed under the terms of the GNU General Public
8 * License version 2, as published by the Free Software Foundation, and
9 * may be copied, distributed, and modified under those terms.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
18 /* This source file contains the implementation of a special device driver
19 * that intends to provide a *very* fast communication channel between the
20 * guest system and the QEMU emulator.
22 * Usage from the guest is simply the following (error handling simplified):
24 * int fd = open("/dev/qemu_pipe",O_RDWR);
25 * .... write() or read() through the pipe.
27 * This driver doesn't deal with the exact protocol used during the session.
28 * It is intended to be as simple as something like:
30 * // do this _just_ after opening the fd to connect to a specific
31 * // emulator service.
32 * const char* msg = "<pipename>";
33 * if (write(fd, msg, strlen(msg)+1) < 0) {
34 * ... could not connect to <pipename> service
35 * close(fd);
36 * }
38 * // after this, simply read() and write() to communicate with the
39 * // service. Exact protocol details left as an exercise to the reader.
41 * This driver is very fast because it doesn't copy any data through
42 * intermediate buffers, since the emulator is capable of translating
43 * guest user addresses into host ones.
45 * Note that we must however ensure that each user page involved in the
46 * exchange is properly mapped during a transfer.
50 #include <linux/module.h>
51 #include <linux/mod_devicetable.h>
52 #include <linux/interrupt.h>
53 #include <linux/kernel.h>
54 #include <linux/spinlock.h>
55 #include <linux/miscdevice.h>
56 #include <linux/platform_device.h>
57 #include <linux/poll.h>
58 #include <linux/sched.h>
59 #include <linux/bitops.h>
60 #include <linux/slab.h>
61 #include <linux/io.h>
62 #include <linux/goldfish.h>
63 #include <linux/dma-mapping.h>
64 #include <linux/mm.h>
65 #include <linux/acpi.h>
68 * Update this when something changes in the driver's behavior so the host
69 * can benefit from knowing it
71 enum {
72 PIPE_DRIVER_VERSION = 2,
73 PIPE_CURRENT_DEVICE_VERSION = 2
77 * IMPORTANT: The following constants must match the ones used and defined
78 * in external/qemu/hw/goldfish_pipe.c in the Android source tree.
81 /* List of bitflags returned in status of CMD_POLL command */
82 enum PipePollFlags {
83 PIPE_POLL_IN = 1 << 0,
84 PIPE_POLL_OUT = 1 << 1,
85 PIPE_POLL_HUP = 1 << 2
88 /* Possible status values used to signal errors - see goldfish_pipe_error_convert */
89 enum PipeErrors {
90 PIPE_ERROR_INVAL = -1,
91 PIPE_ERROR_AGAIN = -2,
92 PIPE_ERROR_NOMEM = -3,
93 PIPE_ERROR_IO = -4
96 /* Bit-flags used to signal events from the emulator */
97 enum PipeWakeFlags {
98 PIPE_WAKE_CLOSED = 1 << 0, /* emulator closed pipe */
99 PIPE_WAKE_READ = 1 << 1, /* pipe can now be read from */
100 PIPE_WAKE_WRITE = 1 << 2 /* pipe can now be written to */
103 /* Bit flags for the 'flags' field */
104 enum PipeFlagsBits {
105 BIT_CLOSED_ON_HOST = 0, /* pipe closed by host */
106 BIT_WAKE_ON_WRITE = 1, /* want to be woken on writes */
107 BIT_WAKE_ON_READ = 2, /* want to be woken on reads */
110 enum PipeRegs {
111 PIPE_REG_CMD = 0,
113 PIPE_REG_SIGNAL_BUFFER_HIGH = 4,
114 PIPE_REG_SIGNAL_BUFFER = 8,
115 PIPE_REG_SIGNAL_BUFFER_COUNT = 12,
117 PIPE_REG_OPEN_BUFFER_HIGH = 20,
118 PIPE_REG_OPEN_BUFFER = 24,
120 PIPE_REG_VERSION = 36,
122 PIPE_REG_GET_SIGNALLED = 48,
125 enum PipeCmdCode {
126 PIPE_CMD_OPEN = 1, /* to be used by the pipe device itself */
127 PIPE_CMD_CLOSE,
128 PIPE_CMD_POLL,
129 PIPE_CMD_WRITE,
130 PIPE_CMD_WAKE_ON_WRITE,
131 PIPE_CMD_READ,
132 PIPE_CMD_WAKE_ON_READ,
135 * TODO(zyy): implement a deferred read/write execution to allow
136 * parallel processing of pipe operations on the host.
138 PIPE_CMD_WAKE_ON_DONE_IO,
141 enum {
142 MAX_BUFFERS_PER_COMMAND = 336,
143 MAX_SIGNALLED_PIPES = 64,
144 INITIAL_PIPES_CAPACITY = 64
147 struct goldfish_pipe_dev;
148 struct goldfish_pipe;
149 struct goldfish_pipe_command;
151 /* A per-pipe command structure, shared with the host */
152 struct goldfish_pipe_command {
153 s32 cmd; /* PipeCmdCode, guest -> host */
154 s32 id; /* pipe id, guest -> host */
155 s32 status; /* command execution status, host -> guest */
156 s32 reserved; /* to pad to 64-bit boundary */
157 union {
158 /* Parameters for PIPE_CMD_{READ,WRITE} */
159 struct {
160 /* number of buffers, guest -> host */
161 u32 buffers_count;
162 /* number of consumed bytes, host -> guest */
163 s32 consumed_size;
164 /* buffer pointers, guest -> host */
165 u64 ptrs[MAX_BUFFERS_PER_COMMAND];
166 /* buffer sizes, guest -> host */
167 u32 sizes[MAX_BUFFERS_PER_COMMAND];
168 } rw_params;
172 /* A single signalled pipe information */
173 struct signalled_pipe_buffer {
174 u32 id;
175 u32 flags;
178 /* Parameters for the PIPE_CMD_OPEN command */
179 struct open_command_param {
180 u64 command_buffer_ptr;
181 u32 rw_params_max_count;
184 /* Device-level set of buffers shared with the host */
185 struct goldfish_pipe_dev_buffers {
186 struct open_command_param open_command_params;
187 struct signalled_pipe_buffer signalled_pipe_buffers[
188 MAX_SIGNALLED_PIPES];
191 /* This data type models a given pipe instance */
192 struct goldfish_pipe {
193 /* pipe ID - index into goldfish_pipe_dev::pipes array */
194 u32 id;
195 /* The wake flags pipe is waiting for
196 * Note: not protected with any lock, uses atomic operations
197 * and barriers to make it thread-safe.
199 unsigned long flags;
200 /* wake flags host have signalled,
201 * - protected by goldfish_pipe_dev::lock
203 unsigned long signalled_flags;
205 /* A pointer to command buffer */
206 struct goldfish_pipe_command *command_buffer;
208 /* doubly linked list of signalled pipes, protected by
209 * goldfish_pipe_dev::lock
211 struct goldfish_pipe *prev_signalled;
212 struct goldfish_pipe *next_signalled;
215 * A pipe's own lock. Protects the following:
216 * - *command_buffer - makes sure a command can safely write its
217 * parameters to the host and read the results back.
219 struct mutex lock;
221 /* A wake queue for sleeping until host signals an event */
222 wait_queue_head_t wake_queue;
223 /* Pointer to the parent goldfish_pipe_dev instance */
224 struct goldfish_pipe_dev *dev;
227 /* The global driver data. Holds a reference to the i/o page used to
228 * communicate with the emulator, and a wake queue for blocked tasks
229 * waiting to be awoken.
231 struct goldfish_pipe_dev {
233 * Global device spinlock. Protects the following members:
234 * - pipes, pipes_capacity
235 * - [*pipes, *pipes + pipes_capacity) - array data
236 * - first_signalled_pipe,
237 * goldfish_pipe::prev_signalled,
238 * goldfish_pipe::next_signalled,
239 * goldfish_pipe::signalled_flags - all singnalled-related fields,
240 * in all allocated pipes
241 * - open_command_params - PIPE_CMD_OPEN-related buffers
243 * It looks like a lot of different fields, but the trick is that
244 * the only operation that happens often is the signalled pipes array
245 * manipulation. That's why it's OK for now to keep the rest of the
246 * fields under the same lock. If we notice too much contention because
247 * of PIPE_CMD_OPEN, then we should add a separate lock there.
249 spinlock_t lock;
252 * Array of the pipes of |pipes_capacity| elements,
253 * indexed by goldfish_pipe::id
255 struct goldfish_pipe **pipes;
256 u32 pipes_capacity;
258 /* Pointers to the buffers host uses for interaction with this driver */
259 struct goldfish_pipe_dev_buffers *buffers;
261 /* Head of a doubly linked list of signalled pipes */
262 struct goldfish_pipe *first_signalled_pipe;
264 /* Some device-specific data */
265 int irq;
266 int version;
267 unsigned char __iomem *base;
270 static struct goldfish_pipe_dev pipe_dev[1] = {};
272 static int goldfish_cmd_locked(struct goldfish_pipe *pipe, enum PipeCmdCode cmd)
274 pipe->command_buffer->cmd = cmd;
275 /* failure by default */
276 pipe->command_buffer->status = PIPE_ERROR_INVAL;
277 writel(pipe->id, pipe->dev->base + PIPE_REG_CMD);
278 return pipe->command_buffer->status;
281 static int goldfish_cmd(struct goldfish_pipe *pipe, enum PipeCmdCode cmd)
283 int status;
285 if (mutex_lock_interruptible(&pipe->lock))
286 return PIPE_ERROR_IO;
287 status = goldfish_cmd_locked(pipe, cmd);
288 mutex_unlock(&pipe->lock);
289 return status;
293 * This function converts an error code returned by the emulator through
294 * the PIPE_REG_STATUS i/o register into a valid negative errno value.
296 static int goldfish_pipe_error_convert(int status)
298 switch (status) {
299 case PIPE_ERROR_AGAIN:
300 return -EAGAIN;
301 case PIPE_ERROR_NOMEM:
302 return -ENOMEM;
303 case PIPE_ERROR_IO:
304 return -EIO;
305 default:
306 return -EINVAL;
310 static int pin_user_pages(unsigned long first_page, unsigned long last_page,
311 unsigned int last_page_size, int is_write,
312 struct page *pages[MAX_BUFFERS_PER_COMMAND],
313 unsigned int *iter_last_page_size)
315 int ret;
316 int requested_pages = ((last_page - first_page) >> PAGE_SHIFT) + 1;
318 if (requested_pages > MAX_BUFFERS_PER_COMMAND) {
319 requested_pages = MAX_BUFFERS_PER_COMMAND;
320 *iter_last_page_size = PAGE_SIZE;
321 } else {
322 *iter_last_page_size = last_page_size;
325 ret = get_user_pages_fast(
326 first_page, requested_pages, !is_write, pages);
327 if (ret <= 0)
328 return -EFAULT;
329 if (ret < requested_pages)
330 *iter_last_page_size = PAGE_SIZE;
331 return ret;
335 static void release_user_pages(struct page **pages, int pages_count,
336 int is_write, s32 consumed_size)
338 int i;
340 for (i = 0; i < pages_count; i++) {
341 if (!is_write && consumed_size > 0)
342 set_page_dirty(pages[i]);
343 put_page(pages[i]);
347 /* Populate the call parameters, merging adjacent pages together */
348 static void populate_rw_params(
349 struct page **pages, int pages_count,
350 unsigned long address, unsigned long address_end,
351 unsigned long first_page, unsigned long last_page,
352 unsigned int iter_last_page_size, int is_write,
353 struct goldfish_pipe_command *command)
356 * Process the first page separately - it's the only page that
357 * needs special handling for its start address.
359 unsigned long xaddr = page_to_phys(pages[0]);
360 unsigned long xaddr_prev = xaddr;
361 int buffer_idx = 0;
362 int i = 1;
363 int size_on_page = first_page == last_page
364 ? (int)(address_end - address)
365 : (PAGE_SIZE - (address & ~PAGE_MASK));
366 command->rw_params.ptrs[0] = (u64)(xaddr | (address & ~PAGE_MASK));
367 command->rw_params.sizes[0] = size_on_page;
368 for (; i < pages_count; ++i) {
369 xaddr = page_to_phys(pages[i]);
370 size_on_page = (i == pages_count - 1) ?
371 iter_last_page_size : PAGE_SIZE;
372 if (xaddr == xaddr_prev + PAGE_SIZE) {
373 command->rw_params.sizes[buffer_idx] += size_on_page;
374 } else {
375 ++buffer_idx;
376 command->rw_params.ptrs[buffer_idx] = (u64)xaddr;
377 command->rw_params.sizes[buffer_idx] = size_on_page;
379 xaddr_prev = xaddr;
381 command->rw_params.buffers_count = buffer_idx + 1;
384 static int transfer_max_buffers(struct goldfish_pipe *pipe,
385 unsigned long address, unsigned long address_end, int is_write,
386 unsigned long last_page, unsigned int last_page_size,
387 s32 *consumed_size, int *status)
389 static struct page *pages[MAX_BUFFERS_PER_COMMAND];
390 unsigned long first_page = address & PAGE_MASK;
391 unsigned int iter_last_page_size;
392 int pages_count = pin_user_pages(first_page, last_page,
393 last_page_size, is_write,
394 pages, &iter_last_page_size);
396 if (pages_count < 0)
397 return pages_count;
399 /* Serialize access to the pipe command buffers */
400 if (mutex_lock_interruptible(&pipe->lock))
401 return -ERESTARTSYS;
403 populate_rw_params(pages, pages_count, address, address_end,
404 first_page, last_page, iter_last_page_size, is_write,
405 pipe->command_buffer);
407 /* Transfer the data */
408 *status = goldfish_cmd_locked(pipe,
409 is_write ? PIPE_CMD_WRITE : PIPE_CMD_READ);
411 *consumed_size = pipe->command_buffer->rw_params.consumed_size;
413 release_user_pages(pages, pages_count, is_write, *consumed_size);
415 mutex_unlock(&pipe->lock);
417 return 0;
420 static int wait_for_host_signal(struct goldfish_pipe *pipe, int is_write)
422 u32 wakeBit = is_write ? BIT_WAKE_ON_WRITE : BIT_WAKE_ON_READ;
424 set_bit(wakeBit, &pipe->flags);
426 /* Tell the emulator we're going to wait for a wake event */
427 (void)goldfish_cmd(pipe,
428 is_write ? PIPE_CMD_WAKE_ON_WRITE : PIPE_CMD_WAKE_ON_READ);
430 while (test_bit(wakeBit, &pipe->flags)) {
431 if (wait_event_interruptible(
432 pipe->wake_queue,
433 !test_bit(wakeBit, &pipe->flags)))
434 return -ERESTARTSYS;
436 if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
437 return -EIO;
440 return 0;
443 static ssize_t goldfish_pipe_read_write(struct file *filp,
444 char __user *buffer, size_t bufflen, int is_write)
446 struct goldfish_pipe *pipe = filp->private_data;
447 int count = 0, ret = -EINVAL;
448 unsigned long address, address_end, last_page;
449 unsigned int last_page_size;
451 /* If the emulator already closed the pipe, no need to go further */
452 if (unlikely(test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)))
453 return -EIO;
454 /* Null reads or writes succeeds */
455 if (unlikely(bufflen == 0))
456 return 0;
457 /* Check the buffer range for access */
458 if (unlikely(!access_ok(is_write ? VERIFY_WRITE : VERIFY_READ,
459 buffer, bufflen)))
460 return -EFAULT;
462 address = (unsigned long)buffer;
463 address_end = address + bufflen;
464 last_page = (address_end - 1) & PAGE_MASK;
465 last_page_size = ((address_end - 1) & ~PAGE_MASK) + 1;
467 while (address < address_end) {
468 s32 consumed_size;
469 int status;
471 ret = transfer_max_buffers(pipe, address, address_end, is_write,
472 last_page, last_page_size, &consumed_size,
473 &status);
474 if (ret < 0)
475 break;
477 if (consumed_size > 0) {
478 /* No matter what's the status, we've transferred
479 * something.
481 count += consumed_size;
482 address += consumed_size;
484 if (status > 0)
485 continue;
486 if (status == 0) {
487 /* EOF */
488 ret = 0;
489 break;
491 if (count > 0) {
493 * An error occurred, but we already transferred
494 * something on one of the previous iterations.
495 * Just return what we already copied and log this
496 * err.
498 if (status != PIPE_ERROR_AGAIN)
499 pr_info_ratelimited("goldfish_pipe: backend error %d on %s\n",
500 status, is_write ? "write" : "read");
501 break;
505 * If the error is not PIPE_ERROR_AGAIN, or if we are in
506 * non-blocking mode, just return the error code.
508 if (status != PIPE_ERROR_AGAIN ||
509 (filp->f_flags & O_NONBLOCK) != 0) {
510 ret = goldfish_pipe_error_convert(status);
511 break;
514 status = wait_for_host_signal(pipe, is_write);
515 if (status < 0)
516 return status;
519 if (count > 0)
520 return count;
521 return ret;
524 static ssize_t goldfish_pipe_read(struct file *filp, char __user *buffer,
525 size_t bufflen, loff_t *ppos)
527 return goldfish_pipe_read_write(filp, buffer, bufflen,
528 /* is_write */ 0);
531 static ssize_t goldfish_pipe_write(struct file *filp,
532 const char __user *buffer, size_t bufflen,
533 loff_t *ppos)
535 return goldfish_pipe_read_write(filp,
536 /* cast away the const */(char __user *)buffer, bufflen,
537 /* is_write */ 1);
540 static __poll_t goldfish_pipe_poll(struct file *filp, poll_table *wait)
542 struct goldfish_pipe *pipe = filp->private_data;
543 __poll_t mask = 0;
544 int status;
546 poll_wait(filp, &pipe->wake_queue, wait);
548 status = goldfish_cmd(pipe, PIPE_CMD_POLL);
549 if (status < 0)
550 return -ERESTARTSYS;
552 if (status & PIPE_POLL_IN)
553 mask |= EPOLLIN | EPOLLRDNORM;
554 if (status & PIPE_POLL_OUT)
555 mask |= EPOLLOUT | EPOLLWRNORM;
556 if (status & PIPE_POLL_HUP)
557 mask |= EPOLLHUP;
558 if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
559 mask |= EPOLLERR;
561 return mask;
564 static void signalled_pipes_add_locked(struct goldfish_pipe_dev *dev,
565 u32 id, u32 flags)
567 struct goldfish_pipe *pipe;
569 if (WARN_ON(id >= dev->pipes_capacity))
570 return;
572 pipe = dev->pipes[id];
573 if (!pipe)
574 return;
575 pipe->signalled_flags |= flags;
577 if (pipe->prev_signalled || pipe->next_signalled
578 || dev->first_signalled_pipe == pipe)
579 return; /* already in the list */
580 pipe->next_signalled = dev->first_signalled_pipe;
581 if (dev->first_signalled_pipe)
582 dev->first_signalled_pipe->prev_signalled = pipe;
583 dev->first_signalled_pipe = pipe;
586 static void signalled_pipes_remove_locked(struct goldfish_pipe_dev *dev,
587 struct goldfish_pipe *pipe) {
588 if (pipe->prev_signalled)
589 pipe->prev_signalled->next_signalled = pipe->next_signalled;
590 if (pipe->next_signalled)
591 pipe->next_signalled->prev_signalled = pipe->prev_signalled;
592 if (pipe == dev->first_signalled_pipe)
593 dev->first_signalled_pipe = pipe->next_signalled;
594 pipe->prev_signalled = NULL;
595 pipe->next_signalled = NULL;
598 static struct goldfish_pipe *signalled_pipes_pop_front(
599 struct goldfish_pipe_dev *dev, int *wakes)
601 struct goldfish_pipe *pipe;
602 unsigned long flags;
604 spin_lock_irqsave(&dev->lock, flags);
606 pipe = dev->first_signalled_pipe;
607 if (pipe) {
608 *wakes = pipe->signalled_flags;
609 pipe->signalled_flags = 0;
611 * This is an optimized version of
612 * signalled_pipes_remove_locked()
613 * - We want to make it as fast as possible to
614 * wake the sleeping pipe operations faster.
616 dev->first_signalled_pipe = pipe->next_signalled;
617 if (dev->first_signalled_pipe)
618 dev->first_signalled_pipe->prev_signalled = NULL;
619 pipe->next_signalled = NULL;
622 spin_unlock_irqrestore(&dev->lock, flags);
623 return pipe;
626 static void goldfish_interrupt_task(unsigned long unused)
628 struct goldfish_pipe_dev *dev = pipe_dev;
629 /* Iterate over the signalled pipes and wake them one by one */
630 struct goldfish_pipe *pipe;
631 int wakes;
633 while ((pipe = signalled_pipes_pop_front(dev, &wakes)) != NULL) {
634 if (wakes & PIPE_WAKE_CLOSED) {
635 pipe->flags = 1 << BIT_CLOSED_ON_HOST;
636 } else {
637 if (wakes & PIPE_WAKE_READ)
638 clear_bit(BIT_WAKE_ON_READ, &pipe->flags);
639 if (wakes & PIPE_WAKE_WRITE)
640 clear_bit(BIT_WAKE_ON_WRITE, &pipe->flags);
643 * wake_up_interruptible() implies a write barrier, so don't
644 * explicitly add another one here.
646 wake_up_interruptible(&pipe->wake_queue);
649 static DECLARE_TASKLET(goldfish_interrupt_tasklet, goldfish_interrupt_task, 0);
652 * The general idea of the interrupt handling:
654 * 1. device raises an interrupt if there's at least one signalled pipe
655 * 2. IRQ handler reads the signalled pipes and their count from the device
656 * 3. device writes them into a shared buffer and returns the count
657 * it only resets the IRQ if it has returned all signalled pipes,
658 * otherwise it leaves it raised, so IRQ handler will be called
659 * again for the next chunk
660 * 4. IRQ handler adds all returned pipes to the device's signalled pipes list
661 * 5. IRQ handler launches a tasklet to process the signalled pipes from the
662 * list in a separate context
664 static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id)
666 u32 count;
667 u32 i;
668 unsigned long flags;
669 struct goldfish_pipe_dev *dev = dev_id;
671 if (dev != pipe_dev)
672 return IRQ_NONE;
674 /* Request the signalled pipes from the device */
675 spin_lock_irqsave(&dev->lock, flags);
677 count = readl(dev->base + PIPE_REG_GET_SIGNALLED);
678 if (count == 0) {
679 spin_unlock_irqrestore(&dev->lock, flags);
680 return IRQ_NONE;
682 if (count > MAX_SIGNALLED_PIPES)
683 count = MAX_SIGNALLED_PIPES;
685 for (i = 0; i < count; ++i)
686 signalled_pipes_add_locked(dev,
687 dev->buffers->signalled_pipe_buffers[i].id,
688 dev->buffers->signalled_pipe_buffers[i].flags);
690 spin_unlock_irqrestore(&dev->lock, flags);
692 tasklet_schedule(&goldfish_interrupt_tasklet);
693 return IRQ_HANDLED;
696 static int get_free_pipe_id_locked(struct goldfish_pipe_dev *dev)
698 int id;
700 for (id = 0; id < dev->pipes_capacity; ++id)
701 if (!dev->pipes[id])
702 return id;
705 /* Reallocate the array */
706 u32 new_capacity = 2 * dev->pipes_capacity;
707 struct goldfish_pipe **pipes =
708 kcalloc(new_capacity, sizeof(*pipes), GFP_ATOMIC);
709 if (!pipes)
710 return -ENOMEM;
711 memcpy(pipes, dev->pipes, sizeof(*pipes) * dev->pipes_capacity);
712 kfree(dev->pipes);
713 dev->pipes = pipes;
714 id = dev->pipes_capacity;
715 dev->pipes_capacity = new_capacity;
717 return id;
721 * goldfish_pipe_open - open a channel to the AVD
722 * @inode: inode of device
723 * @file: file struct of opener
725 * Create a new pipe link between the emulator and the use application.
726 * Each new request produces a new pipe.
728 * Note: we use the pipe ID as a mux. All goldfish emulations are 32bit
729 * right now so this is fine. A move to 64bit will need this addressing
731 static int goldfish_pipe_open(struct inode *inode, struct file *file)
733 struct goldfish_pipe_dev *dev = pipe_dev;
734 unsigned long flags;
735 int id;
736 int status;
738 /* Allocate new pipe kernel object */
739 struct goldfish_pipe *pipe = kzalloc(sizeof(*pipe), GFP_KERNEL);
740 if (pipe == NULL)
741 return -ENOMEM;
743 pipe->dev = dev;
744 mutex_init(&pipe->lock);
745 init_waitqueue_head(&pipe->wake_queue);
748 * Command buffer needs to be allocated on its own page to make sure
749 * it is physically contiguous in host's address space.
751 pipe->command_buffer =
752 (struct goldfish_pipe_command *)__get_free_page(GFP_KERNEL);
753 if (!pipe->command_buffer) {
754 status = -ENOMEM;
755 goto err_pipe;
758 spin_lock_irqsave(&dev->lock, flags);
760 id = get_free_pipe_id_locked(dev);
761 if (id < 0) {
762 status = id;
763 goto err_id_locked;
766 dev->pipes[id] = pipe;
767 pipe->id = id;
768 pipe->command_buffer->id = id;
770 /* Now tell the emulator we're opening a new pipe. */
771 dev->buffers->open_command_params.rw_params_max_count =
772 MAX_BUFFERS_PER_COMMAND;
773 dev->buffers->open_command_params.command_buffer_ptr =
774 (u64)(unsigned long)__pa(pipe->command_buffer);
775 status = goldfish_cmd_locked(pipe, PIPE_CMD_OPEN);
776 spin_unlock_irqrestore(&dev->lock, flags);
777 if (status < 0)
778 goto err_cmd;
779 /* All is done, save the pipe into the file's private data field */
780 file->private_data = pipe;
781 return 0;
783 err_cmd:
784 spin_lock_irqsave(&dev->lock, flags);
785 dev->pipes[id] = NULL;
786 err_id_locked:
787 spin_unlock_irqrestore(&dev->lock, flags);
788 free_page((unsigned long)pipe->command_buffer);
789 err_pipe:
790 kfree(pipe);
791 return status;
794 static int goldfish_pipe_release(struct inode *inode, struct file *filp)
796 unsigned long flags;
797 struct goldfish_pipe *pipe = filp->private_data;
798 struct goldfish_pipe_dev *dev = pipe->dev;
800 /* The guest is closing the channel, so tell the emulator right now */
801 (void)goldfish_cmd(pipe, PIPE_CMD_CLOSE);
803 spin_lock_irqsave(&dev->lock, flags);
804 dev->pipes[pipe->id] = NULL;
805 signalled_pipes_remove_locked(dev, pipe);
806 spin_unlock_irqrestore(&dev->lock, flags);
808 filp->private_data = NULL;
809 free_page((unsigned long)pipe->command_buffer);
810 kfree(pipe);
811 return 0;
814 static const struct file_operations goldfish_pipe_fops = {
815 .owner = THIS_MODULE,
816 .read = goldfish_pipe_read,
817 .write = goldfish_pipe_write,
818 .poll = goldfish_pipe_poll,
819 .open = goldfish_pipe_open,
820 .release = goldfish_pipe_release,
823 static struct miscdevice goldfish_pipe_dev = {
824 .minor = MISC_DYNAMIC_MINOR,
825 .name = "goldfish_pipe",
826 .fops = &goldfish_pipe_fops,
829 static int goldfish_pipe_device_init(struct platform_device *pdev)
831 char *page;
832 struct goldfish_pipe_dev *dev = pipe_dev;
833 int err = devm_request_irq(&pdev->dev, dev->irq,
834 goldfish_pipe_interrupt,
835 IRQF_SHARED, "goldfish_pipe", dev);
836 if (err) {
837 dev_err(&pdev->dev, "unable to allocate IRQ for v2\n");
838 return err;
841 err = misc_register(&goldfish_pipe_dev);
842 if (err) {
843 dev_err(&pdev->dev, "unable to register v2 device\n");
844 return err;
847 dev->first_signalled_pipe = NULL;
848 dev->pipes_capacity = INITIAL_PIPES_CAPACITY;
849 dev->pipes = kcalloc(dev->pipes_capacity, sizeof(*dev->pipes),
850 GFP_KERNEL);
851 if (!dev->pipes)
852 return -ENOMEM;
855 * We're going to pass two buffers, open_command_params and
856 * signalled_pipe_buffers, to the host. This means each of those buffers
857 * needs to be contained in a single physical page. The easiest choice
858 * is to just allocate a page and place the buffers in it.
860 if (WARN_ON(sizeof(*dev->buffers) > PAGE_SIZE))
861 return -ENOMEM;
863 page = (char *)__get_free_page(GFP_KERNEL);
864 if (!page) {
865 kfree(dev->pipes);
866 return -ENOMEM;
868 dev->buffers = (struct goldfish_pipe_dev_buffers *)page;
870 /* Send the buffer addresses to the host */
872 u64 paddr = __pa(&dev->buffers->signalled_pipe_buffers);
874 writel((u32)(unsigned long)(paddr >> 32),
875 dev->base + PIPE_REG_SIGNAL_BUFFER_HIGH);
876 writel((u32)(unsigned long)paddr,
877 dev->base + PIPE_REG_SIGNAL_BUFFER);
878 writel((u32)MAX_SIGNALLED_PIPES,
879 dev->base + PIPE_REG_SIGNAL_BUFFER_COUNT);
881 paddr = __pa(&dev->buffers->open_command_params);
882 writel((u32)(unsigned long)(paddr >> 32),
883 dev->base + PIPE_REG_OPEN_BUFFER_HIGH);
884 writel((u32)(unsigned long)paddr,
885 dev->base + PIPE_REG_OPEN_BUFFER);
887 return 0;
890 static void goldfish_pipe_device_deinit(struct platform_device *pdev)
892 struct goldfish_pipe_dev *dev = pipe_dev;
894 misc_deregister(&goldfish_pipe_dev);
895 kfree(dev->pipes);
896 free_page((unsigned long)dev->buffers);
899 static int goldfish_pipe_probe(struct platform_device *pdev)
901 int err;
902 struct resource *r;
903 struct goldfish_pipe_dev *dev = pipe_dev;
905 if (WARN_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE))
906 return -ENOMEM;
908 /* not thread safe, but this should not happen */
909 WARN_ON(dev->base != NULL);
911 spin_lock_init(&dev->lock);
913 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
914 if (r == NULL || resource_size(r) < PAGE_SIZE) {
915 dev_err(&pdev->dev, "can't allocate i/o page\n");
916 return -EINVAL;
918 dev->base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
919 if (dev->base == NULL) {
920 dev_err(&pdev->dev, "ioremap failed\n");
921 return -EINVAL;
924 r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
925 if (r == NULL) {
926 err = -EINVAL;
927 goto error;
929 dev->irq = r->start;
932 * Exchange the versions with the host device
934 * Note: v1 driver used to not report its version, so we write it before
935 * reading device version back: this allows the host implementation to
936 * detect the old driver (if there was no version write before read).
938 writel((u32)PIPE_DRIVER_VERSION, dev->base + PIPE_REG_VERSION);
939 dev->version = readl(dev->base + PIPE_REG_VERSION);
940 if (WARN_ON(dev->version < PIPE_CURRENT_DEVICE_VERSION))
941 return -EINVAL;
943 err = goldfish_pipe_device_init(pdev);
944 if (!err)
945 return 0;
947 error:
948 dev->base = NULL;
949 return err;
952 static int goldfish_pipe_remove(struct platform_device *pdev)
954 struct goldfish_pipe_dev *dev = pipe_dev;
955 goldfish_pipe_device_deinit(pdev);
956 dev->base = NULL;
957 return 0;
960 static const struct acpi_device_id goldfish_pipe_acpi_match[] = {
961 { "GFSH0003", 0 },
962 { },
964 MODULE_DEVICE_TABLE(acpi, goldfish_pipe_acpi_match);
966 static const struct of_device_id goldfish_pipe_of_match[] = {
967 { .compatible = "google,android-pipe", },
970 MODULE_DEVICE_TABLE(of, goldfish_pipe_of_match);
972 static struct platform_driver goldfish_pipe_driver = {
973 .probe = goldfish_pipe_probe,
974 .remove = goldfish_pipe_remove,
975 .driver = {
976 .name = "goldfish_pipe",
977 .of_match_table = goldfish_pipe_of_match,
978 .acpi_match_table = ACPI_PTR(goldfish_pipe_acpi_match),
982 module_platform_driver(goldfish_pipe_driver);
983 MODULE_AUTHOR("David Turner <digit@google.com>");
984 MODULE_LICENSE("GPL");