Orange Pi5 kernel

// 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 {
<------>/* A magic number to check if this is an instance of this struct */
<------>void *magic;
 
<------>/*
<------> * 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 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 goldfish_pin_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 = pin_user_pages_fast(first_page, requested_pages,
<------><------><------><------>  !is_write ? FOLL_WRITE : 0,
<------><------><------><------>  pages);
<------>if (ret <= 0)
<------><------>return -EFAULT;
<------>if (ret < requested_pages)
<------><------>*iter_last_page_size = PAGE_SIZE;
 
<------>return ret;
}
 
/* 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 = goldfish_pin_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;
 
<------>unpin_user_pages_dirty_lock(pipe->pages, pages_count,
<------><------><------><------>    !is_write && *consumed_size > 0);
 
<------>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(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);
<------>}
}
 
static void goldfish_pipe_device_deinit(struct platform_device *pdev,
<------><------><------><------><------>struct goldfish_pipe_dev *dev);
 
/*
 * 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->magic != &goldfish_pipe_device_deinit)
<------><------>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;
}
 
/* A helper function to get the instance of goldfish_pipe_dev from file */
static struct goldfish_pipe_dev *to_goldfish_pipe_dev(struct file *file)
{
<------>struct miscdevice *miscdev = file->private_data;
 
<------>return container_of(miscdev, struct goldfish_pipe_dev, miscdev);
}
 
/**
 *	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 = to_goldfish_pipe_dev(file);
<------>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)
{
<------>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) {
<------><------>misc_deregister(&dev->miscdev);
<------><------>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);
<------><------>misc_deregister(&dev->miscdev);
<------><------>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);
 
<------>platform_set_drvdata(pdev, dev);
<------>return 0;
}
 
static void goldfish_pipe_device_deinit(struct platform_device *pdev,
<------><------><------><------><------>struct goldfish_pipe_dev *dev)
{
<------>misc_deregister(&dev->miscdev);
<------>tasklet_kill(&dev->irq_tasklet);
<------>kfree(dev->pipes);
<------>free_page((unsigned long)dev->buffers);
}
 
static int goldfish_pipe_probe(struct platform_device *pdev)
{
<------>struct resource *r;
<------>struct goldfish_pipe_dev *dev;
 
<------>dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
<------>if (!dev)
<------><------>return -ENOMEM;
 
<------>dev->magic = &goldfish_pipe_device_deinit;
<------>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)
<------><------>return -EINVAL;
 
<------>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(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;
 
<------>return goldfish_pipe_device_init(pdev, dev);
}
 
static int goldfish_pipe_remove(struct platform_device *pdev)
{
<------>struct goldfish_pipe_dev *dev = platform_get_drvdata(pdev);
 
<------>goldfish_pipe_device_deinit(pdev, dev);
<------>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");