v4.19.13 snapshot.
diff --git a/drivers/platform/goldfish/Kconfig b/drivers/platform/goldfish/Kconfig
new file mode 100644
index 0000000..479031a
--- /dev/null
+++ b/drivers/platform/goldfish/Kconfig
@@ -0,0 +1,19 @@
+menuconfig GOLDFISH
+ bool "Platform support for Goldfish virtual devices"
+ depends on X86_32 || X86_64 || ARM || ARM64 || MIPS
+ depends on HAS_IOMEM
+ ---help---
+ Say Y here to get to see options for the Goldfish virtual platform.
+ This option alone does not add any kernel code.
+
+ Unless you are building for the Android Goldfish emulator say N here.
+
+if GOLDFISH
+
+config GOLDFISH_PIPE
+ tristate "Goldfish virtual device for QEMU pipes"
+ ---help---
+ This is a virtual device to drive the QEMU pipe interface used by
+ the Goldfish Android Virtual Device.
+
+endif # GOLDFISH
diff --git a/drivers/platform/goldfish/Makefile b/drivers/platform/goldfish/Makefile
new file mode 100644
index 0000000..e0c202d
--- /dev/null
+++ b/drivers/platform/goldfish/Makefile
@@ -0,0 +1,4 @@
+#
+# Makefile for Goldfish platform specific drivers
+#
+obj-$(CONFIG_GOLDFISH_PIPE) += goldfish_pipe.o
diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
new file mode 100644
index 0000000..2da5675
--- /dev/null
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -0,0 +1,984 @@
+/*
+ * 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 <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/goldfish.h>
+#include <linux/dma-mapping.h>
+#include <linux/mm.h>
+#include <linux/acpi.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 {
+ /* number of buffers, guest -> host */
+ u32 buffers_count;
+ /* number of consumed bytes, host -> guest */
+ s32 consumed_size;
+ /* buffer pointers, guest -> host */
+ u64 ptrs[MAX_BUFFERS_PER_COMMAND];
+ /* buffer sizes, guest -> host */
+ u32 sizes[MAX_BUFFERS_PER_COMMAND];
+ } 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 {
+ /* pipe ID - index into goldfish_pipe_dev::pipes array */
+ u32 id;
+ /* 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 flags;
+ /* wake flags host have signalled,
+ * - protected by goldfish_pipe_dev::lock
+ */
+ unsigned long signalled_flags;
+
+ /* A pointer to command buffer */
+ struct goldfish_pipe_command *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;
+
+ /* A wake queue for sleeping until host signals an event */
+ wait_queue_head_t wake_queue;
+ /* Pointer to the parent goldfish_pipe_dev instance */
+ struct goldfish_pipe_dev *dev;
+};
+
+/* The global driver data. Holds a reference to the i/o page used to
+ * communicate with the emulator, and a wake queue for blocked tasks
+ * waiting to be awoken.
+ */
+struct goldfish_pipe_dev {
+ /*
+ * Global device spinlock. Protects the following members:
+ * - pipes, pipes_capacity
+ * - [*pipes, *pipes + pipes_capacity) - array data
+ * - first_signalled_pipe,
+ * goldfish_pipe::prev_signalled,
+ * goldfish_pipe::next_signalled,
+ * goldfish_pipe::signalled_flags - all singnalled-related fields,
+ * in all allocated pipes
+ * - open_command_params - PIPE_CMD_OPEN-related buffers
+ *
+ * It looks like a lot of different fields, but the trick is that
+ * the only operation that happens often is the signalled pipes array
+ * manipulation. That's why it's OK for now to keep the rest of the
+ * fields under the same lock. If we notice too much contention because
+ * of PIPE_CMD_OPEN, then we should add a separate lock there.
+ */
+ spinlock_t lock;
+
+ /*
+ * Array of the pipes of |pipes_capacity| elements,
+ * indexed by goldfish_pipe::id
+ */
+ struct goldfish_pipe **pipes;
+ u32 pipes_capacity;
+
+ /* Pointers to the buffers host uses for interaction with this driver */
+ struct goldfish_pipe_dev_buffers *buffers;
+
+ /* Head of a doubly linked list of signalled pipes */
+ struct goldfish_pipe *first_signalled_pipe;
+
+ /* Some device-specific data */
+ int irq;
+ int version;
+ unsigned char __iomem *base;
+};
+
+static struct goldfish_pipe_dev pipe_dev[1] = {};
+
+static int goldfish_cmd_locked(struct goldfish_pipe *pipe, enum PipeCmdCode cmd)
+{
+ pipe->command_buffer->cmd = cmd;
+ /* failure by default */
+ pipe->command_buffer->status = PIPE_ERROR_INVAL;
+ 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 int last_page_size, int is_write,
+ struct page *pages[MAX_BUFFERS_PER_COMMAND],
+ unsigned int *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 int 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)
+{
+ static 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;
+
+ release_user_pages(pages, pages_count, is_write, *consumed_size);
+
+ mutex_unlock(&pipe->lock);
+
+ 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 transferred
+ * something.
+ */
+ count += consumed_size;
+ address += consumed_size;
+ }
+ if (status > 0)
+ continue;
+ if (status == 0) {
+ /* EOF */
+ ret = 0;
+ break;
+ }
+ if (count > 0) {
+ /*
+ * An error occurred, but we already transferred
+ * 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 __poll_t goldfish_pipe_poll(struct file *filp, poll_table *wait)
+{
+ struct goldfish_pipe *pipe = filp->private_data;
+ __poll_t 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 |= EPOLLIN | EPOLLRDNORM;
+ if (status & PIPE_POLL_OUT)
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ if (status & PIPE_POLL_HUP)
+ mask |= EPOLLHUP;
+ if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+ mask |= EPOLLERR;
+
+ return mask;
+}
+
+static void signalled_pipes_add_locked(struct goldfish_pipe_dev *dev,
+ u32 id, u32 flags)
+{
+ struct goldfish_pipe *pipe;
+
+ if (WARN_ON(id >= dev->pipes_capacity))
+ return;
+
+ 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);
+ }
+}
+static 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(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.
+ */
+ if (WARN_ON(sizeof(*dev->buffers) > PAGE_SIZE))
+ return -ENOMEM;
+
+ 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(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;
+
+ if (WARN_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE))
+ return -ENOMEM;
+
+ /* 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 (WARN_ON(dev->version < PIPE_CURRENT_DEVICE_VERSION))
+ return -EINVAL;
+
+ err = goldfish_pipe_device_init(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;
+ goldfish_pipe_device_deinit(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");