blob: 8ca709b45e1f95540f2635a6761a7c9e4cabcfd5 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* 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/dma-mapping.h>
#include <linux/mm.h>
#include <linux/acpi.h>
#include <linux/bug.h>
#include "goldfish_pipe_qemu.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
};
enum {
MAX_BUFFERS_PER_COMMAND = 336,
MAX_SIGNALLED_PIPES = 64,
INITIAL_PIPES_CAPACITY = 64
};
struct goldfish_pipe_dev;
/* 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;
/* A buffer of pages, too large to fit into a stack frame */
struct page *pages[MAX_BUFFERS_PER_COMMAND];
};
/* 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;
/* ptr to platform device's device struct */
struct device *pdev_dev;
/* Some device-specific data */
int irq;
int version;
unsigned char __iomem *base;
/* an irq tasklet to run goldfish_interrupt_task */
struct tasklet_struct irq_tasklet;
struct miscdevice miscdev;
};
static struct goldfish_pipe_dev goldfish_pipe_dev;
static int goldfish_pipe_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_pipe_cmd(struct goldfish_pipe *pipe, enum PipeCmdCode cmd)
{
int status;
if (mutex_lock_interruptible(&pipe->lock))
return PIPE_ERROR_IO;
status = goldfish_pipe_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)
{
unsigned long first_page = address & PAGE_MASK;
unsigned int iter_last_page_size;
int pages_count;
/* Serialize access to the pipe command buffers */
if (mutex_lock_interruptible(&pipe->lock))
return -ERESTARTSYS;
pages_count = pin_user_pages(first_page, last_page,
last_page_size, is_write,
pipe->pages, &iter_last_page_size);
if (pages_count < 0) {
mutex_unlock(&pipe->lock);
return pages_count;
}
populate_rw_params(pipe->pages, pages_count, address, address_end,
first_page, last_page, iter_last_page_size, is_write,
pipe->command_buffer);
/* Transfer the data */
*status = goldfish_pipe_cmd_locked(pipe,
is_write ? PIPE_CMD_WRITE : PIPE_CMD_READ);
*consumed_size = pipe->command_buffer->rw_params.consumed_size;
release_user_pages(pipe->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 wake_bit = is_write ? BIT_WAKE_ON_WRITE : BIT_WAKE_ON_READ;
set_bit(wake_bit, &pipe->flags);
/* Tell the emulator we're going to wait for a wake event */
goldfish_pipe_cmd(pipe,
is_write ? PIPE_CMD_WAKE_ON_WRITE : PIPE_CMD_WAKE_ON_READ);
while (test_bit(wake_bit, &pipe->flags)) {
if (wait_event_interruptible(pipe->wake_queue,
!test_bit(wake_bit, &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)
dev_err_ratelimited(pipe->dev->pdev_dev,
"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)
{
/* cast away the const */
char __user *no_const_buffer = (char __user *)buffer;
return goldfish_pipe_read_write(filp, no_const_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_pipe_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 dev_addr)
{
/* Iterate over the signalled pipes and wake them one by one */
struct goldfish_pipe_dev *dev = (struct goldfish_pipe_dev *)dev_addr;
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);
}
}
/*
* 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 != &goldfish_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(&dev->irq_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.
* Since get_free_pipe_id_locked runs with interrupts disabled,
* we don't want to make calls that could lead to sleep.
*/
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 = &goldfish_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)
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.
*/
BUILD_BUG_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE);
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_pipe_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 */
goldfish_pipe_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 void init_miscdevice(struct miscdevice *miscdev)
{
memset(miscdev, 0, sizeof(*miscdev));
miscdev->minor = MISC_DYNAMIC_MINOR;
miscdev->name = "goldfish_pipe";
miscdev->fops = &goldfish_pipe_fops;
}
static void write_pa_addr(void *addr, void __iomem *portl, void __iomem *porth)
{
const unsigned long paddr = __pa(addr);
writel(upper_32_bits(paddr), porth);
writel(lower_32_bits(paddr), portl);
}
static int goldfish_pipe_device_init(struct platform_device *pdev)
{
struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
int err;
tasklet_init(&dev->irq_tasklet, &goldfish_interrupt_task,
(unsigned long)dev);
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;
}
init_miscdevice(&dev->miscdev);
err = misc_register(&dev->miscdev);
if (err) {
dev_err(&pdev->dev, "unable to register v2 device\n");
return err;
}
dev->pdev_dev = &pdev->dev;
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.
*/
BUILD_BUG_ON(sizeof(struct goldfish_pipe_dev_buffers) > PAGE_SIZE);
dev->buffers = (struct goldfish_pipe_dev_buffers *)
__get_free_page(GFP_KERNEL);
if (!dev->buffers) {
kfree(dev->pipes);
return -ENOMEM;
}
/* Send the buffer addresses to the host */
write_pa_addr(&dev->buffers->signalled_pipe_buffers,
dev->base + PIPE_REG_SIGNAL_BUFFER,
dev->base + PIPE_REG_SIGNAL_BUFFER_HIGH);
writel(MAX_SIGNALLED_PIPES,
dev->base + PIPE_REG_SIGNAL_BUFFER_COUNT);
write_pa_addr(&dev->buffers->open_command_params,
dev->base + PIPE_REG_OPEN_BUFFER,
dev->base + PIPE_REG_OPEN_BUFFER_HIGH);
return 0;
}
static void goldfish_pipe_device_deinit(struct platform_device *pdev)
{
misc_deregister(&goldfish_pipe_dev.miscdev);
tasklet_kill(&goldfish_pipe_dev.irq_tasklet);
kfree(goldfish_pipe_dev.pipes);
free_page((unsigned long)goldfish_pipe_dev.buffers);
}
static int goldfish_pipe_probe(struct platform_device *pdev)
{
int err;
struct resource *r;
struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
/* not thread safe, but this should not happen */
WARN_ON(dev->base);
spin_lock_init(&dev->lock);
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!r || 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) {
dev_err(&pdev->dev, "ioremap failed\n");
return -EINVAL;
}
r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!r) {
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 = &goldfish_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 v2");