diff options
Diffstat (limited to 'drivers/platform/goldfish/goldfish_pipe_v2.c')
| -rw-r--r-- | drivers/platform/goldfish/goldfish_pipe_v2.c | 889 |
1 files changed, 889 insertions, 0 deletions
diff --git a/drivers/platform/goldfish/goldfish_pipe_v2.c b/drivers/platform/goldfish/goldfish_pipe_v2.c new file mode 100644 index 000000000000..ad373ed36555 --- /dev/null +++ b/drivers/platform/goldfish/goldfish_pipe_v2.c @@ -0,0 +1,889 @@ +/* + * Copyright (C) 2012 Intel, Inc. + * Copyright (C) 2013 Intel, Inc. + * Copyright (C) 2014 Linaro Limited + * Copyright (C) 2011-2016 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +/* This source file contains the implementation of a special device driver + * that intends to provide a *very* fast communication channel between the + * guest system and the QEMU emulator. + * + * Usage from the guest is simply the following (error handling simplified): + * + * int fd = open("/dev/qemu_pipe",O_RDWR); + * .... write() or read() through the pipe. + * + * This driver doesn't deal with the exact protocol used during the session. + * It is intended to be as simple as something like: + * + * // do this _just_ after opening the fd to connect to a specific + * // emulator service. + * const char* msg = "<pipename>"; + * if (write(fd, msg, strlen(msg)+1) < 0) { + * ... could not connect to <pipename> service + * close(fd); + * } + * + * // after this, simply read() and write() to communicate with the + * // service. Exact protocol details left as an exercise to the reader. + * + * This driver is very fast because it doesn't copy any data through + * intermediate buffers, since the emulator is capable of translating + * guest user addresses into host ones. + * + * Note that we must however ensure that each user page involved in the + * exchange is properly mapped during a transfer. + */ + +#include "goldfish_pipe.h" + + +/* + * Update this when something changes in the driver's behavior so the host + * can benefit from knowing it + */ +enum { + PIPE_DRIVER_VERSION = 2, + PIPE_CURRENT_DEVICE_VERSION = 2 +}; + +/* + * IMPORTANT: The following constants must match the ones used and defined + * in external/qemu/hw/goldfish_pipe.c in the Android source tree. + */ + +/* List of bitflags returned in status of CMD_POLL command */ +enum PipePollFlags { + PIPE_POLL_IN = 1 << 0, + PIPE_POLL_OUT = 1 << 1, + PIPE_POLL_HUP = 1 << 2 +}; + +/* Possible status values used to signal errors - see goldfish_pipe_error_convert */ +enum PipeErrors { + PIPE_ERROR_INVAL = -1, + PIPE_ERROR_AGAIN = -2, + PIPE_ERROR_NOMEM = -3, + PIPE_ERROR_IO = -4 +}; + +/* Bit-flags used to signal events from the emulator */ +enum PipeWakeFlags { + PIPE_WAKE_CLOSED = 1 << 0, /* emulator closed pipe */ + PIPE_WAKE_READ = 1 << 1, /* pipe can now be read from */ + PIPE_WAKE_WRITE = 1 << 2 /* pipe can now be written to */ +}; + +/* Bit flags for the 'flags' field */ +enum PipeFlagsBits { + BIT_CLOSED_ON_HOST = 0, /* pipe closed by host */ + BIT_WAKE_ON_WRITE = 1, /* want to be woken on writes */ + BIT_WAKE_ON_READ = 2, /* want to be woken on reads */ +}; + +enum PipeRegs { + PIPE_REG_CMD = 0, + + PIPE_REG_SIGNAL_BUFFER_HIGH = 4, + PIPE_REG_SIGNAL_BUFFER = 8, + PIPE_REG_SIGNAL_BUFFER_COUNT = 12, + + PIPE_REG_OPEN_BUFFER_HIGH = 20, + PIPE_REG_OPEN_BUFFER = 24, + + PIPE_REG_VERSION = 36, + + PIPE_REG_GET_SIGNALLED = 48, +}; + +enum PipeCmdCode { + PIPE_CMD_OPEN = 1, /* to be used by the pipe device itself */ + PIPE_CMD_CLOSE, + PIPE_CMD_POLL, + PIPE_CMD_WRITE, + PIPE_CMD_WAKE_ON_WRITE, + PIPE_CMD_READ, + PIPE_CMD_WAKE_ON_READ, + + /* + * TODO(zyy): implement a deferred read/write execution to allow parallel + * processing of pipe operations on the host. + */ + PIPE_CMD_WAKE_ON_DONE_IO, +}; + +enum { + MAX_BUFFERS_PER_COMMAND = 336, + MAX_SIGNALLED_PIPES = 64, + INITIAL_PIPES_CAPACITY = 64 +}; + +struct goldfish_pipe_dev; +struct goldfish_pipe; +struct goldfish_pipe_command; + +/* A per-pipe command structure, shared with the host */ +struct goldfish_pipe_command { + s32 cmd; /* PipeCmdCode, guest -> host */ + s32 id; /* pipe id, guest -> host */ + s32 status; /* command execution status, host -> guest */ + s32 reserved; /* to pad to 64-bit boundary */ + union { + /* Parameters for PIPE_CMD_{READ,WRITE} */ + struct { + u32 buffers_count; /* number of buffers, guest -> host */ + s32 consumed_size; /* number of consumed bytes, host -> guest */ + u64 ptrs[MAX_BUFFERS_PER_COMMAND]; /* buffer pointers, guest -> host */ + u32 sizes[MAX_BUFFERS_PER_COMMAND]; /* buffer sizes, guest -> host */ + } rw_params; + }; +}; + +/* A single signalled pipe information */ +struct signalled_pipe_buffer { + u32 id; + u32 flags; +}; + +/* Parameters for the PIPE_CMD_OPEN command */ +struct open_command_param { + u64 command_buffer_ptr; + u32 rw_params_max_count; +}; + +/* Device-level set of buffers shared with the host */ +struct goldfish_pipe_dev_buffers { + struct open_command_param open_command_params; + struct signalled_pipe_buffer signalled_pipe_buffers[MAX_SIGNALLED_PIPES]; +}; + +/* This data type models a given pipe instance */ +struct goldfish_pipe { + u32 id; /* pipe ID - index into goldfish_pipe_dev::pipes array */ + unsigned long flags; /* The wake flags pipe is waiting for + * Note: not protected with any lock, uses atomic operations + * and barriers to make it thread-safe. + */ + unsigned long signalled_flags; /* wake flags host have signalled, + * - protected by goldfish_pipe_dev::lock */ + + struct goldfish_pipe_command *command_buffer; /* A pointer to command buffer */ + + /* doubly linked list of signalled pipes, protected by goldfish_pipe_dev::lock */ + struct goldfish_pipe *prev_signalled; + struct goldfish_pipe *next_signalled; + + /* + * A pipe's own lock. Protects the following: + * - *command_buffer - makes sure a command can safely write its parameters + * to the host and read the results back. + */ + struct mutex lock; + + wait_queue_head_t wake_queue; /* A wake queue for sleeping until host signals an event */ + struct goldfish_pipe_dev *dev; /* Pointer to the parent goldfish_pipe_dev instance */ +}; + +struct goldfish_pipe_dev pipe_dev[1] = {}; + +static int goldfish_cmd_locked(struct goldfish_pipe *pipe, enum PipeCmdCode cmd) +{ + pipe->command_buffer->cmd = cmd; + pipe->command_buffer->status = PIPE_ERROR_INVAL; /* failure by default */ + writel(pipe->id, pipe->dev->base + PIPE_REG_CMD); + return pipe->command_buffer->status; +} + +static int goldfish_cmd(struct goldfish_pipe *pipe, enum PipeCmdCode cmd) +{ + int status; + if (mutex_lock_interruptible(&pipe->lock)) + return PIPE_ERROR_IO; + status = goldfish_cmd_locked(pipe, cmd); + mutex_unlock(&pipe->lock); + return status; +} + +/* + * This function converts an error code returned by the emulator through + * the PIPE_REG_STATUS i/o register into a valid negative errno value. + */ +static int goldfish_pipe_error_convert(int status) +{ + switch (status) { + case PIPE_ERROR_AGAIN: + return -EAGAIN; + case PIPE_ERROR_NOMEM: + return -ENOMEM; + case PIPE_ERROR_IO: + return -EIO; + default: + return -EINVAL; + } +} + +static int pin_user_pages(unsigned long first_page, unsigned long last_page, + unsigned last_page_size, int is_write, + struct page *pages[MAX_BUFFERS_PER_COMMAND], unsigned *iter_last_page_size) +{ + int ret; + int requested_pages = ((last_page - first_page) >> PAGE_SHIFT) + 1; + if (requested_pages > MAX_BUFFERS_PER_COMMAND) { + requested_pages = MAX_BUFFERS_PER_COMMAND; + *iter_last_page_size = PAGE_SIZE; + } else { + *iter_last_page_size = last_page_size; + } + + ret = get_user_pages_fast( + first_page, requested_pages, !is_write, pages); + if (ret <= 0) + return -EFAULT; + if (ret < requested_pages) + *iter_last_page_size = PAGE_SIZE; + return ret; + +} + +static void release_user_pages(struct page **pages, int pages_count, + int is_write, s32 consumed_size) +{ + int i; + for (i = 0; i < pages_count; i++) { + if (!is_write && consumed_size > 0) { + set_page_dirty(pages[i]); + } + put_page(pages[i]); + } +} + +/* Populate the call parameters, merging adjacent pages together */ +static void populate_rw_params( + struct page **pages, int pages_count, + unsigned long address, unsigned long address_end, + unsigned long first_page, unsigned long last_page, + unsigned iter_last_page_size, int is_write, + struct goldfish_pipe_command *command) +{ + /* + * Process the first page separately - it's the only page that + * needs special handling for its start address. + */ + unsigned long xaddr = page_to_phys(pages[0]); + unsigned long xaddr_prev = xaddr; + int buffer_idx = 0; + int i = 1; + int size_on_page = first_page == last_page + ? (int)(address_end - address) + : (PAGE_SIZE - (address & ~PAGE_MASK)); + command->rw_params.ptrs[0] = (u64)(xaddr | (address & ~PAGE_MASK)); + command->rw_params.sizes[0] = size_on_page; + for (; i < pages_count; ++i) { + xaddr = page_to_phys(pages[i]); + size_on_page = (i == pages_count - 1) ? iter_last_page_size : PAGE_SIZE; + if (xaddr == xaddr_prev + PAGE_SIZE) { + command->rw_params.sizes[buffer_idx] += size_on_page; + } else { + ++buffer_idx; + command->rw_params.ptrs[buffer_idx] = (u64)xaddr; + command->rw_params.sizes[buffer_idx] = size_on_page; + } + xaddr_prev = xaddr; + } + command->rw_params.buffers_count = buffer_idx + 1; +} + +static int transfer_max_buffers(struct goldfish_pipe* pipe, + unsigned long address, unsigned long address_end, int is_write, + unsigned long last_page, unsigned int last_page_size, + s32* consumed_size, int* status) +{ + struct page *pages[MAX_BUFFERS_PER_COMMAND]; + unsigned long first_page = address & PAGE_MASK; + unsigned int iter_last_page_size; + int pages_count = pin_user_pages(first_page, last_page, + last_page_size, is_write, + pages, &iter_last_page_size); + if (pages_count < 0) + return pages_count; + + /* Serialize access to the pipe command buffers */ + if (mutex_lock_interruptible(&pipe->lock)) + return -ERESTARTSYS; + + populate_rw_params(pages, pages_count, address, address_end, + first_page, last_page, iter_last_page_size, is_write, + pipe->command_buffer); + + /* Transfer the data */ + *status = goldfish_cmd_locked(pipe, + is_write ? PIPE_CMD_WRITE : PIPE_CMD_READ); + + *consumed_size = pipe->command_buffer->rw_params.consumed_size; + + mutex_unlock(&pipe->lock); + + release_user_pages(pages, pages_count, is_write, *consumed_size); + + return 0; +} + +static int wait_for_host_signal(struct goldfish_pipe *pipe, int is_write) +{ + u32 wakeBit = is_write ? BIT_WAKE_ON_WRITE : BIT_WAKE_ON_READ; + set_bit(wakeBit, &pipe->flags); + + /* Tell the emulator we're going to wait for a wake event */ + (void)goldfish_cmd(pipe, + is_write ? PIPE_CMD_WAKE_ON_WRITE : PIPE_CMD_WAKE_ON_READ); + + while (test_bit(wakeBit, &pipe->flags)) { + if (wait_event_interruptible( + pipe->wake_queue, + !test_bit(wakeBit, &pipe->flags))) + return -ERESTARTSYS; + + if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)) + return -EIO; + } + + return 0; +} + +static ssize_t goldfish_pipe_read_write(struct file *filp, + char __user *buffer, size_t bufflen, int is_write) +{ + struct goldfish_pipe *pipe = filp->private_data; + int count = 0, ret = -EINVAL; + unsigned long address, address_end, last_page; + unsigned int last_page_size; + + /* If the emulator already closed the pipe, no need to go further */ + if (unlikely(test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))) + return -EIO; + /* Null reads or writes succeeds */ + if (unlikely(bufflen == 0)) + return 0; + /* Check the buffer range for access */ + if (unlikely(!access_ok(is_write ? VERIFY_WRITE : VERIFY_READ, + buffer, bufflen))) + return -EFAULT; + + address = (unsigned long)buffer; + address_end = address + bufflen; + last_page = (address_end - 1) & PAGE_MASK; + last_page_size = ((address_end - 1) & ~PAGE_MASK) + 1; + + while (address < address_end) { + s32 consumed_size; + int status; + ret = transfer_max_buffers(pipe, address, address_end, is_write, + last_page, last_page_size, &consumed_size, &status); + if (ret < 0) + break; + + if (consumed_size > 0) { + /* No matter what's the status, we've transfered something */ + count += consumed_size; + address += consumed_size; + } + if (status > 0) + continue; + if (status == 0) { + /* EOF */ + ret = 0; + break; + } + if (count > 0) { + /* + * An error occured, but we already transfered + * something on one of the previous iterations. + * Just return what we already copied and log this + * err. + */ + if (status != PIPE_ERROR_AGAIN) + pr_info_ratelimited("goldfish_pipe: backend error %d on %s\n", + status, is_write ? "write" : "read"); + break; + } + + /* + * If the error is not PIPE_ERROR_AGAIN, or if we are in + * non-blocking mode, just return the error code. + */ + if (status != PIPE_ERROR_AGAIN || (filp->f_flags & O_NONBLOCK) != 0) { + ret = goldfish_pipe_error_convert(status); + break; + } + + status = wait_for_host_signal(pipe, is_write); + if (status < 0) + return status; + } + + if (count > 0) + return count; + return ret; +} + +static ssize_t goldfish_pipe_read(struct file *filp, char __user *buffer, + size_t bufflen, loff_t *ppos) +{ + return goldfish_pipe_read_write(filp, buffer, bufflen, /* is_write */ 0); +} + +static ssize_t goldfish_pipe_write(struct file *filp, + const char __user *buffer, size_t bufflen, + loff_t *ppos) +{ + return goldfish_pipe_read_write(filp, + /* cast away the const */(char __user *)buffer, bufflen, + /* is_write */ 1); +} + +static unsigned int goldfish_pipe_poll(struct file *filp, poll_table *wait) +{ + struct goldfish_pipe *pipe = filp->private_data; + unsigned int mask = 0; + int status; + + poll_wait(filp, &pipe->wake_queue, wait); + + status = goldfish_cmd(pipe, PIPE_CMD_POLL); + if (status < 0) { + return -ERESTARTSYS; + } + + if (status & PIPE_POLL_IN) + mask |= POLLIN | POLLRDNORM; + if (status & PIPE_POLL_OUT) + mask |= POLLOUT | POLLWRNORM; + if (status & PIPE_POLL_HUP) + mask |= POLLHUP; + if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)) + mask |= POLLERR; + + return mask; +} + +static void signalled_pipes_add_locked(struct goldfish_pipe_dev *dev, + u32 id, u32 flags) +{ + struct goldfish_pipe *pipe; + + BUG_ON(id >= dev->pipes_capacity); + + pipe = dev->pipes[id]; + if (!pipe) + return; + pipe->signalled_flags |= flags; + + if (pipe->prev_signalled || pipe->next_signalled + || dev->first_signalled_pipe == pipe) + return; /* already in the list */ + pipe->next_signalled = dev->first_signalled_pipe; + if (dev->first_signalled_pipe) { + dev->first_signalled_pipe->prev_signalled = pipe; + } + dev->first_signalled_pipe = pipe; +} + +static void signalled_pipes_remove_locked(struct goldfish_pipe_dev *dev, + struct goldfish_pipe *pipe) { + if (pipe->prev_signalled) + pipe->prev_signalled->next_signalled = pipe->next_signalled; + if (pipe->next_signalled) + pipe->next_signalled->prev_signalled = pipe->prev_signalled; + if (pipe == dev->first_signalled_pipe) + dev->first_signalled_pipe = pipe->next_signalled; + pipe->prev_signalled = NULL; + pipe->next_signalled = NULL; +} + +static struct goldfish_pipe *signalled_pipes_pop_front(struct goldfish_pipe_dev *dev, + int *wakes) +{ + struct goldfish_pipe *pipe; + unsigned long flags; + spin_lock_irqsave(&dev->lock, flags); + + pipe = dev->first_signalled_pipe; + if (pipe) { + *wakes = pipe->signalled_flags; + pipe->signalled_flags = 0; + /* + * This is an optimized version of signalled_pipes_remove_locked() - + * we want to make it as fast as possible to wake the sleeping pipe + * operations faster + */ + dev->first_signalled_pipe = pipe->next_signalled; + if (dev->first_signalled_pipe) + dev->first_signalled_pipe->prev_signalled = NULL; + pipe->next_signalled = NULL; + } + + spin_unlock_irqrestore(&dev->lock, flags); + return pipe; +} + +static void goldfish_interrupt_task(unsigned long unused) +{ + struct goldfish_pipe_dev *dev = pipe_dev; + /* Iterate over the signalled pipes and wake them one by one */ + struct goldfish_pipe *pipe; + int wakes; + while ((pipe = signalled_pipes_pop_front(dev, &wakes)) != NULL) { + if (wakes & PIPE_WAKE_CLOSED) { + pipe->flags = 1 << BIT_CLOSED_ON_HOST; + } else { + if (wakes & PIPE_WAKE_READ) + clear_bit(BIT_WAKE_ON_READ, &pipe->flags); + if (wakes & PIPE_WAKE_WRITE) + clear_bit(BIT_WAKE_ON_WRITE, &pipe->flags); + } + /* + * wake_up_interruptible() implies a write barrier, so don't explicitly + * add another one here. + */ + wake_up_interruptible(&pipe->wake_queue); + } +} +DECLARE_TASKLET(goldfish_interrupt_tasklet, goldfish_interrupt_task, 0); + +/* + * The general idea of the interrupt handling: + * + * 1. device raises an interrupt if there's at least one signalled pipe + * 2. IRQ handler reads the signalled pipes and their count from the device + * 3. device writes them into a shared buffer and returns the count + * it only resets the IRQ if it has returned all signalled pipes, + * otherwise it leaves it raised, so IRQ handler will be called + * again for the next chunk + * 4. IRQ handler adds all returned pipes to the device's signalled pipes list + * 5. IRQ handler launches a tasklet to process the signalled pipes from the + * list in a separate context + */ +static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id) +{ + u32 count; + u32 i; + unsigned long flags; + struct goldfish_pipe_dev *dev = dev_id; + if (dev != pipe_dev) + return IRQ_NONE; + + /* Request the signalled pipes from the device */ + spin_lock_irqsave(&dev->lock, flags); + + count = readl(dev->base + PIPE_REG_GET_SIGNALLED); + if (count == 0) { + spin_unlock_irqrestore(&dev->lock, flags); + return IRQ_NONE; + } + if (count > MAX_SIGNALLED_PIPES) + count = MAX_SIGNALLED_PIPES; + + for (i = 0; i < count; ++i) + signalled_pipes_add_locked(dev, + dev->buffers->signalled_pipe_buffers[i].id, + dev->buffers->signalled_pipe_buffers[i].flags); + + spin_unlock_irqrestore(&dev->lock, flags); + + tasklet_schedule(&goldfish_interrupt_tasklet); + return IRQ_HANDLED; +} + +static int get_free_pipe_id_locked(struct goldfish_pipe_dev *dev) +{ + int id; + for (id = 0; id < dev->pipes_capacity; ++id) + if (!dev->pipes[id]) + return id; + + { + /* Reallocate the array */ + u32 new_capacity = 2 * dev->pipes_capacity; + struct goldfish_pipe **pipes = + kcalloc(new_capacity, sizeof(*pipes), + GFP_ATOMIC); + if (!pipes) + return -ENOMEM; + memcpy(pipes, dev->pipes, sizeof(*pipes) * dev->pipes_capacity); + kfree(dev->pipes); + dev->pipes = pipes; + id = dev->pipes_capacity; + dev->pipes_capacity = new_capacity; + } + return id; +} + +/** + * goldfish_pipe_open - open a channel to the AVD + * @inode: inode of device + * @file: file struct of opener + * + * Create a new pipe link between the emulator and the use application. + * Each new request produces a new pipe. + * + * Note: we use the pipe ID as a mux. All goldfish emulations are 32bit + * right now so this is fine. A move to 64bit will need this addressing + */ +static int goldfish_pipe_open(struct inode *inode, struct file *file) +{ + struct goldfish_pipe_dev *dev = pipe_dev; + unsigned long flags; + int id; + int status; + + /* Allocate new pipe kernel object */ + struct goldfish_pipe *pipe = kzalloc(sizeof(*pipe), GFP_KERNEL); + if (pipe == NULL) + return -ENOMEM; + + pipe->dev = dev; + mutex_init(&pipe->lock); + init_waitqueue_head(&pipe->wake_queue); + + /* + * Command buffer needs to be allocated on its own page to make sure it is + * physically contiguous in host's address space. + */ + pipe->command_buffer = + (struct goldfish_pipe_command*)__get_free_page(GFP_KERNEL); + if (!pipe->command_buffer) { + status = -ENOMEM; + goto err_pipe; + } + + spin_lock_irqsave(&dev->lock, flags); + + id = get_free_pipe_id_locked(dev); + if (id < 0) { + status = id; + goto err_id_locked; + } + + dev->pipes[id] = pipe; + pipe->id = id; + pipe->command_buffer->id = id; + + /* Now tell the emulator we're opening a new pipe. */ + dev->buffers->open_command_params.rw_params_max_count = + MAX_BUFFERS_PER_COMMAND; + dev->buffers->open_command_params.command_buffer_ptr = + (u64)(unsigned long)__pa(pipe->command_buffer); + status = goldfish_cmd_locked(pipe, PIPE_CMD_OPEN); + spin_unlock_irqrestore(&dev->lock, flags); + if (status < 0) + goto err_cmd; + /* All is done, save the pipe into the file's private data field */ + file->private_data = pipe; + return 0; + +err_cmd: + spin_lock_irqsave(&dev->lock, flags); + dev->pipes[id] = NULL; +err_id_locked: + spin_unlock_irqrestore(&dev->lock, flags); + free_page((unsigned long)pipe->command_buffer); +err_pipe: + kfree(pipe); + return status; +} + +static int goldfish_pipe_release(struct inode *inode, struct file *filp) +{ + unsigned long flags; + struct goldfish_pipe *pipe = filp->private_data; + struct goldfish_pipe_dev *dev = pipe->dev; + + /* The guest is closing the channel, so tell the emulator right now */ + (void)goldfish_cmd(pipe, PIPE_CMD_CLOSE); + + spin_lock_irqsave(&dev->lock, flags); + dev->pipes[pipe->id] = NULL; + signalled_pipes_remove_locked(dev, pipe); + spin_unlock_irqrestore(&dev->lock, flags); + + filp->private_data = NULL; + free_page((unsigned long)pipe->command_buffer); + kfree(pipe); + return 0; +} + +static const struct file_operations goldfish_pipe_fops = { + .owner = THIS_MODULE, + .read = goldfish_pipe_read, + .write = goldfish_pipe_write, + .poll = goldfish_pipe_poll, + .open = goldfish_pipe_open, + .release = goldfish_pipe_release, +}; + +static struct miscdevice goldfish_pipe_dev = { + .minor = MISC_DYNAMIC_MINOR, + .name = "goldfish_pipe", + .fops = &goldfish_pipe_fops, +}; + +static int goldfish_pipe_device_init_v2(struct platform_device *pdev) +{ + char *page; + struct goldfish_pipe_dev *dev = pipe_dev; + int err = devm_request_irq(&pdev->dev, dev->irq, goldfish_pipe_interrupt, + IRQF_SHARED, "goldfish_pipe", dev); + if (err) { + dev_err(&pdev->dev, "unable to allocate IRQ for v2\n"); + return err; + } + + err = misc_register(&goldfish_pipe_dev); + if (err) { + dev_err(&pdev->dev, "unable to register v2 device\n"); + return err; + } + + dev->first_signalled_pipe = NULL; + dev->pipes_capacity = INITIAL_PIPES_CAPACITY; + dev->pipes = kcalloc(dev->pipes_capacity, sizeof(*dev->pipes), GFP_KERNEL); + if (!dev->pipes) + return -ENOMEM; + + /* + * We're going to pass two buffers, open_command_params and + * signalled_pipe_buffers, to the host. This means each of those buffers + * needs to be contained in a single physical page. The easiest choice is + * to just allocate a page and place the buffers in it. + */ + BUG_ON(sizeof(*dev->buffers) > PAGE_SIZE); + page = (char*)__get_free_page(GFP_KERNEL); + if (!page) { + kfree(dev->pipes); + return -ENOMEM; + } + dev->buffers = (struct goldfish_pipe_dev_buffers*)page; + + /* Send the buffer addresses to the host */ + { + u64 paddr = __pa(&dev->buffers->signalled_pipe_buffers); + writel((u32)(unsigned long)(paddr >> 32), dev->base + PIPE_REG_SIGNAL_BUFFER_HIGH); + writel((u32)(unsigned long)paddr, dev->base + PIPE_REG_SIGNAL_BUFFER); + writel((u32)MAX_SIGNALLED_PIPES, dev->base + PIPE_REG_SIGNAL_BUFFER_COUNT); + + paddr = __pa(&dev->buffers->open_command_params); + writel((u32)(unsigned long)(paddr >> 32), dev->base + PIPE_REG_OPEN_BUFFER_HIGH); + writel((u32)(unsigned long)paddr, dev->base + PIPE_REG_OPEN_BUFFER); + } + return 0; +} + +static void goldfish_pipe_device_deinit_v2(struct platform_device *pdev) { + struct goldfish_pipe_dev *dev = pipe_dev; + misc_deregister(&goldfish_pipe_dev); + kfree(dev->pipes); + free_page((unsigned long)dev->buffers); +} + +static int goldfish_pipe_probe(struct platform_device *pdev) +{ + int err; + struct resource *r; + struct goldfish_pipe_dev *dev = pipe_dev; + + BUG_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE); + + /* not thread safe, but this should not happen */ + WARN_ON(dev->base != NULL); + + spin_lock_init(&dev->lock); + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (r == NULL || resource_size(r) < PAGE_SIZE) { + dev_err(&pdev->dev, "can't allocate i/o page\n"); + return -EINVAL; + } + dev->base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE); + if (dev->base == NULL) { + dev_err(&pdev->dev, "ioremap failed\n"); + return -EINVAL; + } + + r = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (r == NULL) { + err = -EINVAL; + goto error; + } + dev->irq = r->start; + + /* + * Exchange the versions with the host device + * + * Note: v1 driver used to not report its version, so we write it before + * reading device version back: this allows the host implementation to + * detect the old driver (if there was no version write before read). + */ + writel((u32)PIPE_DRIVER_VERSION, dev->base + PIPE_REG_VERSION); + dev->version = readl(dev->base + PIPE_REG_VERSION); + if (dev->version < PIPE_CURRENT_DEVICE_VERSION) { + /* initialize the old device version */ + err = goldfish_pipe_device_init_v1(pdev); + } else { + /* Host device supports the new interface */ + err = goldfish_pipe_device_init_v2(pdev); + } + if (!err) + return 0; + +error: + dev->base = NULL; + return err; +} + +static int goldfish_pipe_remove(struct platform_device *pdev) +{ + struct goldfish_pipe_dev *dev = pipe_dev; + if (dev->version < PIPE_CURRENT_DEVICE_VERSION) + goldfish_pipe_device_deinit_v1(pdev); + else + goldfish_pipe_device_deinit_v2(pdev); + dev->base = NULL; + return 0; +} + +static const struct acpi_device_id goldfish_pipe_acpi_match[] = { + { "GFSH0003", 0 }, + { }, +}; +MODULE_DEVICE_TABLE(acpi, goldfish_pipe_acpi_match); + +static const struct of_device_id goldfish_pipe_of_match[] = { + { .compatible = "google,android-pipe", }, + {}, +}; +MODULE_DEVICE_TABLE(of, goldfish_pipe_of_match); + +static struct platform_driver goldfish_pipe_driver = { + .probe = goldfish_pipe_probe, + .remove = goldfish_pipe_remove, + .driver = { + .name = "goldfish_pipe", + .of_match_table = goldfish_pipe_of_match, + .acpi_match_table = ACPI_PTR(goldfish_pipe_acpi_match), + } +}; + +module_platform_driver(goldfish_pipe_driver); +MODULE_AUTHOR("David Turner <digit@google.com>"); +MODULE_LICENSE("GPL"); |