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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2012 Intel, Inc.4 * Copyright (C) 2013 Intel, Inc.5 * Copyright (C) 2014 Linaro Limited6 * Copyright (C) 2011-2016 Google, Inc.7 *8 * This software is licensed under the terms of the GNU General Public9 * License version 2, as published by the Free Software Foundation, and10 * may be copied, distributed, and modified under those terms.11 *12 * This program is distributed in the hope that it will be useful,13 * but WITHOUT ANY WARRANTY; without even the implied warranty of14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the15 * GNU General Public License for more details.16 *17 */18 19/* This source file contains the implementation of a special device driver20 * that intends to provide a *very* fast communication channel between the21 * guest system and the QEMU emulator.22 *23 * Usage from the guest is simply the following (error handling simplified):24 *25 * int fd = open("/dev/qemu_pipe",O_RDWR);26 * .... write() or read() through the pipe.27 *28 * This driver doesn't deal with the exact protocol used during the session.29 * It is intended to be as simple as something like:30 *31 * // do this _just_ after opening the fd to connect to a specific32 * // emulator service.33 * const char* msg = "<pipename>";34 * if (write(fd, msg, strlen(msg)+1) < 0) {35 * ... could not connect to <pipename> service36 * close(fd);37 * }38 *39 * // after this, simply read() and write() to communicate with the40 * // service. Exact protocol details left as an exercise to the reader.41 *42 * This driver is very fast because it doesn't copy any data through43 * intermediate buffers, since the emulator is capable of translating44 * guest user addresses into host ones.45 *46 * Note that we must however ensure that each user page involved in the47 * exchange is properly mapped during a transfer.48 */49 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/dma-mapping.h>63#include <linux/mm.h>64#include <linux/acpi.h>65#include <linux/bug.h>66#include "goldfish_pipe_qemu.h"67 68/*69 * Update this when something changes in the driver's behavior so the host70 * can benefit from knowing it71 */72enum {73 PIPE_DRIVER_VERSION = 2,74 PIPE_CURRENT_DEVICE_VERSION = 275};76 77enum {78 MAX_BUFFERS_PER_COMMAND = 336,79 MAX_SIGNALLED_PIPES = 64,80 INITIAL_PIPES_CAPACITY = 6481};82 83struct goldfish_pipe_dev;84 85/* A per-pipe command structure, shared with the host */86struct goldfish_pipe_command {87 s32 cmd; /* PipeCmdCode, guest -> host */88 s32 id; /* pipe id, guest -> host */89 s32 status; /* command execution status, host -> guest */90 s32 reserved; /* to pad to 64-bit boundary */91 union {92 /* Parameters for PIPE_CMD_{READ,WRITE} */93 struct {94 /* number of buffers, guest -> host */95 u32 buffers_count;96 /* number of consumed bytes, host -> guest */97 s32 consumed_size;98 /* buffer pointers, guest -> host */99 u64 ptrs[MAX_BUFFERS_PER_COMMAND];100 /* buffer sizes, guest -> host */101 u32 sizes[MAX_BUFFERS_PER_COMMAND];102 } rw_params;103 };104};105 106/* A single signalled pipe information */107struct signalled_pipe_buffer {108 u32 id;109 u32 flags;110};111 112/* Parameters for the PIPE_CMD_OPEN command */113struct open_command_param {114 u64 command_buffer_ptr;115 u32 rw_params_max_count;116};117 118/* Device-level set of buffers shared with the host */119struct goldfish_pipe_dev_buffers {120 struct open_command_param open_command_params;121 struct signalled_pipe_buffer122 signalled_pipe_buffers[MAX_SIGNALLED_PIPES];123};124 125/* This data type models a given pipe instance */126struct goldfish_pipe {127 /* pipe ID - index into goldfish_pipe_dev::pipes array */128 u32 id;129 130 /* The wake flags pipe is waiting for131 * Note: not protected with any lock, uses atomic operations132 * and barriers to make it thread-safe.133 */134 unsigned long flags;135 136 /* wake flags host have signalled,137 * - protected by goldfish_pipe_dev::lock138 */139 unsigned long signalled_flags;140 141 /* A pointer to command buffer */142 struct goldfish_pipe_command *command_buffer;143 144 /* doubly linked list of signalled pipes, protected by145 * goldfish_pipe_dev::lock146 */147 struct goldfish_pipe *prev_signalled;148 struct goldfish_pipe *next_signalled;149 150 /*151 * A pipe's own lock. Protects the following:152 * - *command_buffer - makes sure a command can safely write its153 * parameters to the host and read the results back.154 */155 struct mutex lock;156 157 /* A wake queue for sleeping until host signals an event */158 wait_queue_head_t wake_queue;159 160 /* Pointer to the parent goldfish_pipe_dev instance */161 struct goldfish_pipe_dev *dev;162 163 /* A buffer of pages, too large to fit into a stack frame */164 struct page *pages[MAX_BUFFERS_PER_COMMAND];165};166 167/* The global driver data. Holds a reference to the i/o page used to168 * communicate with the emulator, and a wake queue for blocked tasks169 * waiting to be awoken.170 */171struct goldfish_pipe_dev {172 /* A magic number to check if this is an instance of this struct */173 void *magic;174 175 /*176 * Global device spinlock. Protects the following members:177 * - pipes, pipes_capacity178 * - [*pipes, *pipes + pipes_capacity) - array data179 * - first_signalled_pipe,180 * goldfish_pipe::prev_signalled,181 * goldfish_pipe::next_signalled,182 * goldfish_pipe::signalled_flags - all singnalled-related fields,183 * in all allocated pipes184 * - open_command_params - PIPE_CMD_OPEN-related buffers185 *186 * It looks like a lot of different fields, but the trick is that187 * the only operation that happens often is the signalled pipes array188 * manipulation. That's why it's OK for now to keep the rest of the189 * fields under the same lock. If we notice too much contention because190 * of PIPE_CMD_OPEN, then we should add a separate lock there.191 */192 spinlock_t lock;193 194 /*195 * Array of the pipes of |pipes_capacity| elements,196 * indexed by goldfish_pipe::id197 */198 struct goldfish_pipe **pipes;199 u32 pipes_capacity;200 201 /* Pointers to the buffers host uses for interaction with this driver */202 struct goldfish_pipe_dev_buffers *buffers;203 204 /* Head of a doubly linked list of signalled pipes */205 struct goldfish_pipe *first_signalled_pipe;206 207 /* ptr to platform device's device struct */208 struct device *pdev_dev;209 210 /* Some device-specific data */211 int irq;212 int version;213 unsigned char __iomem *base;214 215 struct miscdevice miscdev;216};217 218static int goldfish_pipe_cmd_locked(struct goldfish_pipe *pipe,219 enum PipeCmdCode cmd)220{221 pipe->command_buffer->cmd = cmd;222 /* failure by default */223 pipe->command_buffer->status = PIPE_ERROR_INVAL;224 writel(pipe->id, pipe->dev->base + PIPE_REG_CMD);225 return pipe->command_buffer->status;226}227 228static int goldfish_pipe_cmd(struct goldfish_pipe *pipe, enum PipeCmdCode cmd)229{230 int status;231 232 if (mutex_lock_interruptible(&pipe->lock))233 return PIPE_ERROR_IO;234 status = goldfish_pipe_cmd_locked(pipe, cmd);235 mutex_unlock(&pipe->lock);236 return status;237}238 239/*240 * This function converts an error code returned by the emulator through241 * the PIPE_REG_STATUS i/o register into a valid negative errno value.242 */243static int goldfish_pipe_error_convert(int status)244{245 switch (status) {246 case PIPE_ERROR_AGAIN:247 return -EAGAIN;248 case PIPE_ERROR_NOMEM:249 return -ENOMEM;250 case PIPE_ERROR_IO:251 return -EIO;252 default:253 return -EINVAL;254 }255}256 257static int goldfish_pin_pages(unsigned long first_page,258 unsigned long last_page,259 unsigned int last_page_size,260 int is_write,261 struct page *pages[MAX_BUFFERS_PER_COMMAND],262 unsigned int *iter_last_page_size)263{264 int ret;265 int requested_pages = ((last_page - first_page) >> PAGE_SHIFT) + 1;266 267 if (requested_pages > MAX_BUFFERS_PER_COMMAND) {268 requested_pages = MAX_BUFFERS_PER_COMMAND;269 *iter_last_page_size = PAGE_SIZE;270 } else {271 *iter_last_page_size = last_page_size;272 }273 274 ret = pin_user_pages_fast(first_page, requested_pages,275 !is_write ? FOLL_WRITE : 0,276 pages);277 if (ret <= 0)278 return -EFAULT;279 if (ret < requested_pages)280 *iter_last_page_size = PAGE_SIZE;281 282 return ret;283}284 285/* Populate the call parameters, merging adjacent pages together */286static void populate_rw_params(struct page **pages,287 int pages_count,288 unsigned long address,289 unsigned long address_end,290 unsigned long first_page,291 unsigned long last_page,292 unsigned int iter_last_page_size,293 int is_write,294 struct goldfish_pipe_command *command)295{296 /*297 * Process the first page separately - it's the only page that298 * needs special handling for its start address.299 */300 unsigned long xaddr = page_to_phys(pages[0]);301 unsigned long xaddr_prev = xaddr;302 int buffer_idx = 0;303 int i = 1;304 int size_on_page = first_page == last_page305 ? (int)(address_end - address)306 : (PAGE_SIZE - (address & ~PAGE_MASK));307 command->rw_params.ptrs[0] = (u64)(xaddr | (address & ~PAGE_MASK));308 command->rw_params.sizes[0] = size_on_page;309 for (; i < pages_count; ++i) {310 xaddr = page_to_phys(pages[i]);311 size_on_page = (i == pages_count - 1) ?312 iter_last_page_size : PAGE_SIZE;313 if (xaddr == xaddr_prev + PAGE_SIZE) {314 command->rw_params.sizes[buffer_idx] += size_on_page;315 } else {316 ++buffer_idx;317 command->rw_params.ptrs[buffer_idx] = (u64)xaddr;318 command->rw_params.sizes[buffer_idx] = size_on_page;319 }320 xaddr_prev = xaddr;321 }322 command->rw_params.buffers_count = buffer_idx + 1;323}324 325static int transfer_max_buffers(struct goldfish_pipe *pipe,326 unsigned long address,327 unsigned long address_end,328 int is_write,329 unsigned long last_page,330 unsigned int last_page_size,331 s32 *consumed_size,332 int *status)333{334 unsigned long first_page = address & PAGE_MASK;335 unsigned int iter_last_page_size;336 int pages_count;337 338 /* Serialize access to the pipe command buffers */339 if (mutex_lock_interruptible(&pipe->lock))340 return -ERESTARTSYS;341 342 pages_count = goldfish_pin_pages(first_page, last_page,343 last_page_size, is_write,344 pipe->pages, &iter_last_page_size);345 if (pages_count < 0) {346 mutex_unlock(&pipe->lock);347 return pages_count;348 }349 350 populate_rw_params(pipe->pages, pages_count, address, address_end,351 first_page, last_page, iter_last_page_size, is_write,352 pipe->command_buffer);353 354 /* Transfer the data */355 *status = goldfish_pipe_cmd_locked(pipe,356 is_write ? PIPE_CMD_WRITE : PIPE_CMD_READ);357 358 *consumed_size = pipe->command_buffer->rw_params.consumed_size;359 360 unpin_user_pages_dirty_lock(pipe->pages, pages_count,361 !is_write && *consumed_size > 0);362 363 mutex_unlock(&pipe->lock);364 return 0;365}366 367static int wait_for_host_signal(struct goldfish_pipe *pipe, int is_write)368{369 u32 wake_bit = is_write ? BIT_WAKE_ON_WRITE : BIT_WAKE_ON_READ;370 371 set_bit(wake_bit, &pipe->flags);372 373 /* Tell the emulator we're going to wait for a wake event */374 goldfish_pipe_cmd(pipe,375 is_write ? PIPE_CMD_WAKE_ON_WRITE : PIPE_CMD_WAKE_ON_READ);376 377 while (test_bit(wake_bit, &pipe->flags)) {378 if (wait_event_interruptible(pipe->wake_queue,379 !test_bit(wake_bit, &pipe->flags)))380 return -ERESTARTSYS;381 382 if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))383 return -EIO;384 }385 386 return 0;387}388 389static ssize_t goldfish_pipe_read_write(struct file *filp,390 char __user *buffer,391 size_t bufflen,392 int is_write)393{394 struct goldfish_pipe *pipe = filp->private_data;395 int count = 0, ret = -EINVAL;396 unsigned long address, address_end, last_page;397 unsigned int last_page_size;398 399 /* If the emulator already closed the pipe, no need to go further */400 if (unlikely(test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)))401 return -EIO;402 /* Null reads or writes succeeds */403 if (unlikely(bufflen == 0))404 return 0;405 /* Check the buffer range for access */406 if (unlikely(!access_ok(buffer, bufflen)))407 return -EFAULT;408 409 address = (unsigned long)buffer;410 address_end = address + bufflen;411 last_page = (address_end - 1) & PAGE_MASK;412 last_page_size = ((address_end - 1) & ~PAGE_MASK) + 1;413 414 while (address < address_end) {415 s32 consumed_size;416 int status;417 418 ret = transfer_max_buffers(pipe, address, address_end, is_write,419 last_page, last_page_size,420 &consumed_size, &status);421 if (ret < 0)422 break;423 424 if (consumed_size > 0) {425 /* No matter what's the status, we've transferred426 * something.427 */428 count += consumed_size;429 address += consumed_size;430 }431 if (status > 0)432 continue;433 if (status == 0) {434 /* EOF */435 ret = 0;436 break;437 }438 if (count > 0) {439 /*440 * An error occurred, but we already transferred441 * something on one of the previous iterations.442 * Just return what we already copied and log this443 * err.444 */445 if (status != PIPE_ERROR_AGAIN)446 dev_err_ratelimited(pipe->dev->pdev_dev,447 "backend error %d on %s\n",448 status, is_write ? "write" : "read");449 break;450 }451 452 /*453 * If the error is not PIPE_ERROR_AGAIN, or if we are in454 * non-blocking mode, just return the error code.455 */456 if (status != PIPE_ERROR_AGAIN ||457 (filp->f_flags & O_NONBLOCK) != 0) {458 ret = goldfish_pipe_error_convert(status);459 break;460 }461 462 status = wait_for_host_signal(pipe, is_write);463 if (status < 0)464 return status;465 }466 467 if (count > 0)468 return count;469 return ret;470}471 472static ssize_t goldfish_pipe_read(struct file *filp, char __user *buffer,473 size_t bufflen, loff_t *ppos)474{475 return goldfish_pipe_read_write(filp, buffer, bufflen,476 /* is_write */ 0);477}478 479static ssize_t goldfish_pipe_write(struct file *filp,480 const char __user *buffer, size_t bufflen,481 loff_t *ppos)482{483 /* cast away the const */484 char __user *no_const_buffer = (char __user *)buffer;485 486 return goldfish_pipe_read_write(filp, no_const_buffer, bufflen,487 /* is_write */ 1);488}489 490static __poll_t goldfish_pipe_poll(struct file *filp, poll_table *wait)491{492 struct goldfish_pipe *pipe = filp->private_data;493 __poll_t mask = 0;494 int status;495 496 poll_wait(filp, &pipe->wake_queue, wait);497 498 status = goldfish_pipe_cmd(pipe, PIPE_CMD_POLL);499 if (status < 0)500 return -ERESTARTSYS;501 502 if (status & PIPE_POLL_IN)503 mask |= EPOLLIN | EPOLLRDNORM;504 if (status & PIPE_POLL_OUT)505 mask |= EPOLLOUT | EPOLLWRNORM;506 if (status & PIPE_POLL_HUP)507 mask |= EPOLLHUP;508 if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))509 mask |= EPOLLERR;510 511 return mask;512}513 514static void signalled_pipes_add_locked(struct goldfish_pipe_dev *dev,515 u32 id, u32 flags)516{517 struct goldfish_pipe *pipe;518 519 if (WARN_ON(id >= dev->pipes_capacity))520 return;521 522 pipe = dev->pipes[id];523 if (!pipe)524 return;525 pipe->signalled_flags |= flags;526 527 if (pipe->prev_signalled || pipe->next_signalled ||528 dev->first_signalled_pipe == pipe)529 return; /* already in the list */530 pipe->next_signalled = dev->first_signalled_pipe;531 if (dev->first_signalled_pipe)532 dev->first_signalled_pipe->prev_signalled = pipe;533 dev->first_signalled_pipe = pipe;534}535 536static void signalled_pipes_remove_locked(struct goldfish_pipe_dev *dev,537 struct goldfish_pipe *pipe)538{539 if (pipe->prev_signalled)540 pipe->prev_signalled->next_signalled = pipe->next_signalled;541 if (pipe->next_signalled)542 pipe->next_signalled->prev_signalled = pipe->prev_signalled;543 if (pipe == dev->first_signalled_pipe)544 dev->first_signalled_pipe = pipe->next_signalled;545 pipe->prev_signalled = NULL;546 pipe->next_signalled = NULL;547}548 549static struct goldfish_pipe *signalled_pipes_pop_front(550 struct goldfish_pipe_dev *dev, int *wakes)551{552 struct goldfish_pipe *pipe;553 unsigned long flags;554 555 spin_lock_irqsave(&dev->lock, flags);556 557 pipe = dev->first_signalled_pipe;558 if (pipe) {559 *wakes = pipe->signalled_flags;560 pipe->signalled_flags = 0;561 /*562 * This is an optimized version of563 * signalled_pipes_remove_locked()564 * - We want to make it as fast as possible to565 * wake the sleeping pipe operations faster.566 */567 dev->first_signalled_pipe = pipe->next_signalled;568 if (dev->first_signalled_pipe)569 dev->first_signalled_pipe->prev_signalled = NULL;570 pipe->next_signalled = NULL;571 }572 573 spin_unlock_irqrestore(&dev->lock, flags);574 return pipe;575}576 577static irqreturn_t goldfish_interrupt_task(int irq, void *dev_addr)578{579 /* Iterate over the signalled pipes and wake them one by one */580 struct goldfish_pipe_dev *dev = dev_addr;581 struct goldfish_pipe *pipe;582 int wakes;583 584 while ((pipe = signalled_pipes_pop_front(dev, &wakes)) != NULL) {585 if (wakes & PIPE_WAKE_CLOSED) {586 pipe->flags = 1 << BIT_CLOSED_ON_HOST;587 } else {588 if (wakes & PIPE_WAKE_READ)589 clear_bit(BIT_WAKE_ON_READ, &pipe->flags);590 if (wakes & PIPE_WAKE_WRITE)591 clear_bit(BIT_WAKE_ON_WRITE, &pipe->flags);592 }593 /*594 * wake_up_interruptible() implies a write barrier, so don't595 * explicitly add another one here.596 */597 wake_up_interruptible(&pipe->wake_queue);598 }599 return IRQ_HANDLED;600}601 602static void goldfish_pipe_device_deinit(struct platform_device *pdev,603 struct goldfish_pipe_dev *dev);604 605/*606 * The general idea of the (threaded) interrupt handling:607 *608 * 1. device raises an interrupt if there's at least one signalled pipe609 * 2. IRQ handler reads the signalled pipes and their count from the device610 * 3. device writes them into a shared buffer and returns the count611 * it only resets the IRQ if it has returned all signalled pipes,612 * otherwise it leaves it raised, so IRQ handler will be called613 * again for the next chunk614 * 4. IRQ handler adds all returned pipes to the device's signalled pipes list615 * 5. IRQ handler defers processing the signalled pipes from the list in a616 * separate context617 */618static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id)619{620 u32 count;621 u32 i;622 unsigned long flags;623 struct goldfish_pipe_dev *dev = dev_id;624 625 if (dev->magic != &goldfish_pipe_device_deinit)626 return IRQ_NONE;627 628 /* Request the signalled pipes from the device */629 spin_lock_irqsave(&dev->lock, flags);630 631 count = readl(dev->base + PIPE_REG_GET_SIGNALLED);632 if (count == 0) {633 spin_unlock_irqrestore(&dev->lock, flags);634 return IRQ_NONE;635 }636 if (count > MAX_SIGNALLED_PIPES)637 count = MAX_SIGNALLED_PIPES;638 639 for (i = 0; i < count; ++i)640 signalled_pipes_add_locked(dev,641 dev->buffers->signalled_pipe_buffers[i].id,642 dev->buffers->signalled_pipe_buffers[i].flags);643 644 spin_unlock_irqrestore(&dev->lock, flags);645 646 return IRQ_WAKE_THREAD;647}648 649static int get_free_pipe_id_locked(struct goldfish_pipe_dev *dev)650{651 int id;652 653 for (id = 0; id < dev->pipes_capacity; ++id)654 if (!dev->pipes[id])655 return id;656 657 {658 /* Reallocate the array.659 * Since get_free_pipe_id_locked runs with interrupts disabled,660 * we don't want to make calls that could lead to sleep.661 */662 u32 new_capacity = 2 * dev->pipes_capacity;663 struct goldfish_pipe **pipes =664 kcalloc(new_capacity, sizeof(*pipes), GFP_ATOMIC);665 if (!pipes)666 return -ENOMEM;667 memcpy(pipes, dev->pipes, sizeof(*pipes) * dev->pipes_capacity);668 kfree(dev->pipes);669 dev->pipes = pipes;670 id = dev->pipes_capacity;671 dev->pipes_capacity = new_capacity;672 }673 return id;674}675 676/* A helper function to get the instance of goldfish_pipe_dev from file */677static struct goldfish_pipe_dev *to_goldfish_pipe_dev(struct file *file)678{679 struct miscdevice *miscdev = file->private_data;680 681 return container_of(miscdev, struct goldfish_pipe_dev, miscdev);682}683 684/**685 * goldfish_pipe_open - open a channel to the AVD686 * @inode: inode of device687 * @file: file struct of opener688 *689 * Create a new pipe link between the emulator and the use application.690 * Each new request produces a new pipe.691 *692 * Note: we use the pipe ID as a mux. All goldfish emulations are 32bit693 * right now so this is fine. A move to 64bit will need this addressing694 */695static int goldfish_pipe_open(struct inode *inode, struct file *file)696{697 struct goldfish_pipe_dev *dev = to_goldfish_pipe_dev(file);698 unsigned long flags;699 int id;700 int status;701 702 /* Allocate new pipe kernel object */703 struct goldfish_pipe *pipe = kzalloc(sizeof(*pipe), GFP_KERNEL);704 705 if (!pipe)706 return -ENOMEM;707 708 pipe->dev = dev;709 mutex_init(&pipe->lock);710 init_waitqueue_head(&pipe->wake_queue);711 712 /*713 * Command buffer needs to be allocated on its own page to make sure714 * it is physically contiguous in host's address space.715 */716 BUILD_BUG_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE);717 pipe->command_buffer =718 (struct goldfish_pipe_command *)__get_free_page(GFP_KERNEL);719 if (!pipe->command_buffer) {720 status = -ENOMEM;721 goto err_pipe;722 }723 724 spin_lock_irqsave(&dev->lock, flags);725 726 id = get_free_pipe_id_locked(dev);727 if (id < 0) {728 status = id;729 goto err_id_locked;730 }731 732 dev->pipes[id] = pipe;733 pipe->id = id;734 pipe->command_buffer->id = id;735 736 /* Now tell the emulator we're opening a new pipe. */737 dev->buffers->open_command_params.rw_params_max_count =738 MAX_BUFFERS_PER_COMMAND;739 dev->buffers->open_command_params.command_buffer_ptr =740 (u64)(unsigned long)__pa(pipe->command_buffer);741 status = goldfish_pipe_cmd_locked(pipe, PIPE_CMD_OPEN);742 spin_unlock_irqrestore(&dev->lock, flags);743 if (status < 0)744 goto err_cmd;745 /* All is done, save the pipe into the file's private data field */746 file->private_data = pipe;747 return 0;748 749err_cmd:750 spin_lock_irqsave(&dev->lock, flags);751 dev->pipes[id] = NULL;752err_id_locked:753 spin_unlock_irqrestore(&dev->lock, flags);754 free_page((unsigned long)pipe->command_buffer);755err_pipe:756 kfree(pipe);757 return status;758}759 760static int goldfish_pipe_release(struct inode *inode, struct file *filp)761{762 unsigned long flags;763 struct goldfish_pipe *pipe = filp->private_data;764 struct goldfish_pipe_dev *dev = pipe->dev;765 766 /* The guest is closing the channel, so tell the emulator right now */767 goldfish_pipe_cmd(pipe, PIPE_CMD_CLOSE);768 769 spin_lock_irqsave(&dev->lock, flags);770 dev->pipes[pipe->id] = NULL;771 signalled_pipes_remove_locked(dev, pipe);772 spin_unlock_irqrestore(&dev->lock, flags);773 774 filp->private_data = NULL;775 free_page((unsigned long)pipe->command_buffer);776 kfree(pipe);777 return 0;778}779 780static const struct file_operations goldfish_pipe_fops = {781 .owner = THIS_MODULE,782 .read = goldfish_pipe_read,783 .write = goldfish_pipe_write,784 .poll = goldfish_pipe_poll,785 .open = goldfish_pipe_open,786 .release = goldfish_pipe_release,787};788 789static void init_miscdevice(struct miscdevice *miscdev)790{791 memset(miscdev, 0, sizeof(*miscdev));792 793 miscdev->minor = MISC_DYNAMIC_MINOR;794 miscdev->name = "goldfish_pipe";795 miscdev->fops = &goldfish_pipe_fops;796}797 798static void write_pa_addr(void *addr, void __iomem *portl, void __iomem *porth)799{800 const unsigned long paddr = __pa(addr);801 802 writel(upper_32_bits(paddr), porth);803 writel(lower_32_bits(paddr), portl);804}805 806static int goldfish_pipe_device_init(struct platform_device *pdev,807 struct goldfish_pipe_dev *dev)808{809 int err;810 811 err = devm_request_threaded_irq(&pdev->dev, dev->irq,812 goldfish_pipe_interrupt,813 goldfish_interrupt_task,814 IRQF_SHARED, "goldfish_pipe", dev);815 if (err) {816 dev_err(&pdev->dev, "unable to allocate IRQ for v2\n");817 return err;818 }819 820 init_miscdevice(&dev->miscdev);821 err = misc_register(&dev->miscdev);822 if (err) {823 dev_err(&pdev->dev, "unable to register v2 device\n");824 return err;825 }826 827 dev->pdev_dev = &pdev->dev;828 dev->first_signalled_pipe = NULL;829 dev->pipes_capacity = INITIAL_PIPES_CAPACITY;830 dev->pipes = kcalloc(dev->pipes_capacity, sizeof(*dev->pipes),831 GFP_KERNEL);832 if (!dev->pipes) {833 misc_deregister(&dev->miscdev);834 return -ENOMEM;835 }836 837 /*838 * We're going to pass two buffers, open_command_params and839 * signalled_pipe_buffers, to the host. This means each of those buffers840 * needs to be contained in a single physical page. The easiest choice841 * is to just allocate a page and place the buffers in it.842 */843 BUILD_BUG_ON(sizeof(struct goldfish_pipe_dev_buffers) > PAGE_SIZE);844 dev->buffers = (struct goldfish_pipe_dev_buffers *)845 __get_free_page(GFP_KERNEL);846 if (!dev->buffers) {847 kfree(dev->pipes);848 misc_deregister(&dev->miscdev);849 return -ENOMEM;850 }851 852 /* Send the buffer addresses to the host */853 write_pa_addr(&dev->buffers->signalled_pipe_buffers,854 dev->base + PIPE_REG_SIGNAL_BUFFER,855 dev->base + PIPE_REG_SIGNAL_BUFFER_HIGH);856 857 writel(MAX_SIGNALLED_PIPES,858 dev->base + PIPE_REG_SIGNAL_BUFFER_COUNT);859 860 write_pa_addr(&dev->buffers->open_command_params,861 dev->base + PIPE_REG_OPEN_BUFFER,862 dev->base + PIPE_REG_OPEN_BUFFER_HIGH);863 864 platform_set_drvdata(pdev, dev);865 return 0;866}867 868static void goldfish_pipe_device_deinit(struct platform_device *pdev,869 struct goldfish_pipe_dev *dev)870{871 misc_deregister(&dev->miscdev);872 kfree(dev->pipes);873 free_page((unsigned long)dev->buffers);874}875 876static int goldfish_pipe_probe(struct platform_device *pdev)877{878 struct resource *r;879 struct goldfish_pipe_dev *dev;880 881 dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);882 if (!dev)883 return -ENOMEM;884 885 dev->magic = &goldfish_pipe_device_deinit;886 spin_lock_init(&dev->lock);887 888 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);889 if (!r || resource_size(r) < PAGE_SIZE) {890 dev_err(&pdev->dev, "can't allocate i/o page\n");891 return -EINVAL;892 }893 dev->base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);894 if (!dev->base) {895 dev_err(&pdev->dev, "ioremap failed\n");896 return -EINVAL;897 }898 899 dev->irq = platform_get_irq(pdev, 0);900 if (dev->irq < 0)901 return dev->irq;902 903 /*904 * Exchange the versions with the host device905 *906 * Note: v1 driver used to not report its version, so we write it before907 * reading device version back: this allows the host implementation to908 * detect the old driver (if there was no version write before read).909 */910 writel(PIPE_DRIVER_VERSION, dev->base + PIPE_REG_VERSION);911 dev->version = readl(dev->base + PIPE_REG_VERSION);912 if (WARN_ON(dev->version < PIPE_CURRENT_DEVICE_VERSION))913 return -EINVAL;914 915 return goldfish_pipe_device_init(pdev, dev);916}917 918static void goldfish_pipe_remove(struct platform_device *pdev)919{920 struct goldfish_pipe_dev *dev = platform_get_drvdata(pdev);921 922 goldfish_pipe_device_deinit(pdev, dev);923}924 925static const struct acpi_device_id goldfish_pipe_acpi_match[] = {926 { "GFSH0003", 0 },927 { },928};929MODULE_DEVICE_TABLE(acpi, goldfish_pipe_acpi_match);930 931static const struct of_device_id goldfish_pipe_of_match[] = {932 { .compatible = "google,android-pipe", },933 {},934};935MODULE_DEVICE_TABLE(of, goldfish_pipe_of_match);936 937static struct platform_driver goldfish_pipe_driver = {938 .probe = goldfish_pipe_probe,939 .remove_new = goldfish_pipe_remove,940 .driver = {941 .name = "goldfish_pipe",942 .of_match_table = goldfish_pipe_of_match,943 .acpi_match_table = ACPI_PTR(goldfish_pipe_acpi_match),944 }945};946 947module_platform_driver(goldfish_pipe_driver);948MODULE_AUTHOR("David Turner <digit@google.com>");949MODULE_DESCRIPTION("Goldfish virtual device for QEMU pipes");950MODULE_LICENSE("GPL v2");951