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Diffstat (limited to 'drivers/platform/goldfish/goldfish_pipe.c')
-rw-r--r--drivers/platform/goldfish/goldfish_pipe.c323
1 files changed, 142 insertions, 181 deletions
diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index e7a29e2750c6..fd1452e28352 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -2,6 +2,7 @@
* Copyright (C) 2011 Google, Inc.
* Copyright (C) 2012 Intel, Inc.
* Copyright (C) 2013 Intel, Inc.
+ * Copyright (C) 2014 Linaro Limited
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
@@ -14,49 +15,11 @@
*
*/
-/* 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.
+/* This source file contains the implementation of the legacy version of
+ * a goldfish pipe device driver. See goldfish_pipe_v2.c for the current
+ * version.
*/
-
-#include <linux/module.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 "goldfish_pipe.h"
/*
* IMPORTANT: The following constants must match the ones used and defined
@@ -75,6 +38,7 @@
#define PIPE_REG_PARAMS_ADDR_LOW 0x18 /* read/write: batch data address */
#define PIPE_REG_PARAMS_ADDR_HIGH 0x1c /* read/write: batch data address */
#define PIPE_REG_ACCESS_PARAMS 0x20 /* write: batch access */
+#define PIPE_REG_VERSION 0x24 /* read: device version */
/* list of commands for PIPE_REG_COMMAND */
#define CMD_OPEN 1 /* open new channel */
@@ -90,12 +54,6 @@
#define CMD_WRITE_BUFFER 4 /* send a user buffer to the emulator */
#define CMD_WAKE_ON_WRITE 5 /* tell the emulator to wake us when writing
is possible */
-
-/* The following commands are related to read operations, they must be
- * listed in the same order than the corresponding write ones, since we
- * will use (CMD_READ_BUFFER - CMD_WRITE_BUFFER) as a special offset
- * in goldfish_pipe_read_write() below.
- */
#define CMD_READ_BUFFER 6 /* receive a user buffer from the emulator */
#define CMD_WAKE_ON_READ 7 /* tell the emulator to wake us when reading
* is possible */
@@ -111,28 +69,15 @@
#define PIPE_WAKE_READ (1 << 1) /* pipe can now be read from */
#define PIPE_WAKE_WRITE (1 << 2) /* pipe can now be written to */
-struct access_params {
- unsigned long channel;
- u32 size;
- unsigned long address;
- u32 cmd;
- u32 result;
- /* reserved for future extension */
- u32 flags;
-};
+#define MAX_PAGES_TO_GRAB 32
-/* 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 {
- spinlock_t lock;
- unsigned char __iomem *base;
- struct access_params *aps;
- int irq;
-};
+#define DEBUG 0
-static struct goldfish_pipe_dev pipe_dev[1];
+#if DEBUG
+#define DPRINT(...) { printk(KERN_ERR __VA_ARGS__); }
+#else
+#define DPRINT(...)
+#endif
/* This data type models a given pipe instance */
struct goldfish_pipe {
@@ -142,6 +87,15 @@ struct goldfish_pipe {
wait_queue_head_t wake_queue;
};
+struct access_params {
+ unsigned long channel;
+ u32 size;
+ unsigned long address;
+ u32 cmd;
+ u32 result;
+ /* reserved for future extension */
+ u32 flags;
+};
/* Bit flags for the 'flags' field */
enum {
@@ -232,8 +186,10 @@ static int setup_access_params_addr(struct platform_device *pdev,
if (valid_batchbuffer_addr(dev, aps)) {
dev->aps = aps;
return 0;
- } else
+ } else {
+ devm_kfree(&pdev->dev, aps);
return -1;
+ }
}
/* A value that will not be set by qemu emulator */
@@ -263,19 +219,15 @@ static int access_with_param(struct goldfish_pipe_dev *dev, const int cmd,
return 0;
}
-/* This function is used for both reading from and writing to a given
- * pipe.
- */
static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
size_t bufflen, int is_write)
{
unsigned long irq_flags;
struct goldfish_pipe *pipe = filp->private_data;
struct goldfish_pipe_dev *dev = pipe->dev;
- const int cmd_offset = is_write ? 0
- : (CMD_READ_BUFFER - CMD_WRITE_BUFFER);
unsigned long address, address_end;
- int ret = 0;
+ struct page* pages[MAX_PAGES_TO_GRAB] = {};
+ int count = 0, ret = -EINVAL;
/* If the emulator already closed the pipe, no need to go further */
if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
@@ -298,79 +250,127 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
address_end = address + bufflen;
while (address < address_end) {
- unsigned long page_end = (address & PAGE_MASK) + PAGE_SIZE;
- unsigned long next = page_end < address_end ? page_end
- : address_end;
- unsigned long avail = next - address;
- int status, wakeBit;
-
- /* Ensure that the corresponding page is properly mapped */
- /* FIXME: this isn't safe or sufficient - use get_user_pages */
- if (is_write) {
- char c;
- /* Ensure that the page is mapped and readable */
- if (__get_user(c, (char __user *)address)) {
- if (!ret)
- ret = -EFAULT;
- break;
- }
- } else {
- /* Ensure that the page is mapped and writable */
- if (__put_user(0, (char __user *)address)) {
- if (!ret)
- ret = -EFAULT;
+ unsigned long page_end = (address & PAGE_MASK) + PAGE_SIZE;
+ unsigned long next, avail;
+ int status, wakeBit, page_i, num_contiguous_pages;
+ long first_page, last_page, requested_pages;
+ unsigned long xaddr, xaddr_prev, xaddr_i;
+
+ /*
+ * Attempt to grab multiple physically contiguous pages.
+ */
+ first_page = address & PAGE_MASK;
+ last_page = (address_end - 1) & PAGE_MASK;
+ requested_pages = ((last_page - first_page) >> PAGE_SHIFT) + 1;
+ if (requested_pages > MAX_PAGES_TO_GRAB) {
+ requested_pages = MAX_PAGES_TO_GRAB;
+ }
+ ret = get_user_pages_fast(first_page, requested_pages,
+ !is_write, pages);
+
+ DPRINT("%s: requested pages: %d %d %p\n", __FUNCTION__,
+ ret, requested_pages, first_page);
+ if (ret == 0) {
+ DPRINT("%s: error: (requested pages == 0) (wanted %d)\n",
+ __FUNCTION__, requested_pages);
+ mutex_unlock(&pipe->lock);
+ return ret;
+ }
+ if (ret < 0) {
+ DPRINT("%s: (requested pages < 0) %d \n",
+ __FUNCTION__, requested_pages);
+ mutex_unlock(&pipe->lock);
+ return ret;
+ }
+
+ xaddr = page_to_phys(pages[0]) | (address & ~PAGE_MASK);
+ xaddr_prev = xaddr;
+ num_contiguous_pages = ret == 0 ? 0 : 1;
+ for (page_i = 1; page_i < ret; page_i++) {
+ xaddr_i = page_to_phys(pages[page_i]) | (address & ~PAGE_MASK);
+ if (xaddr_i == xaddr_prev + PAGE_SIZE) {
+ page_end += PAGE_SIZE;
+ xaddr_prev = xaddr_i;
+ num_contiguous_pages++;
+ } else {
+ DPRINT("%s: discontinuous page boundary: %d pages instead\n",
+ __FUNCTION__, page_i);
break;
}
}
+ next = page_end < address_end ? page_end : address_end;
+ avail = next - address;
/* Now, try to transfer the bytes in the current page */
spin_lock_irqsave(&dev->lock, irq_flags);
- if (access_with_param(dev, CMD_WRITE_BUFFER + cmd_offset,
- address, avail, pipe, &status)) {
+ if (access_with_param(dev,
+ is_write ? CMD_WRITE_BUFFER : CMD_READ_BUFFER,
+ xaddr, avail, pipe, &status)) {
gf_write_ptr(pipe, dev->base + PIPE_REG_CHANNEL,
dev->base + PIPE_REG_CHANNEL_HIGH);
writel(avail, dev->base + PIPE_REG_SIZE);
- gf_write_ptr((void *)address,
+ gf_write_ptr((void *)xaddr,
dev->base + PIPE_REG_ADDRESS,
dev->base + PIPE_REG_ADDRESS_HIGH);
- writel(CMD_WRITE_BUFFER + cmd_offset,
- dev->base + PIPE_REG_COMMAND);
+ writel(is_write ? CMD_WRITE_BUFFER : CMD_READ_BUFFER,
+ dev->base + PIPE_REG_COMMAND);
status = readl(dev->base + PIPE_REG_STATUS);
}
spin_unlock_irqrestore(&dev->lock, irq_flags);
+ for (page_i = 0; page_i < ret; page_i++) {
+ if (status > 0 && !is_write &&
+ page_i < num_contiguous_pages) {
+ set_page_dirty(pages[page_i]);
+ }
+ put_page(pages[page_i]);
+ }
+
if (status > 0) { /* Correct transfer */
- ret += status;
+ count += status;
address += status;
continue;
- }
-
- if (status == 0) /* EOF */
+ } else if (status == 0) { /* EOF */
+ ret = 0;
break;
-
- /* An error occured. If we already transfered stuff, just
- * return with its count. We expect the next call to return
- * an error code */
- if (ret > 0)
+ } else if (status < 0 && count > 0) {
+ /*
+ * An error occured and we already transfered
+ * something on one of the previous pages.
+ * Just return what we already copied and log this
+ * err.
+ *
+ * Note: This seems like an incorrect approach but
+ * cannot change it until we check if any user space
+ * ABI relies on this behavior.
+ */
+ if (status != PIPE_ERROR_AGAIN)
+ pr_info_ratelimited("goldfish_pipe: backend returned error %d on %s\n",
+ status, is_write ? "write" : "read");
+ ret = 0;
break;
+ }
- /* If the error is not PIPE_ERROR_AGAIN, or if we are not in
- * non-blocking mode, just return the error code.
- */
+ /*
+ * If the error is not PIPE_ERROR_AGAIN, or if we are not in
+ * non-blocking mode, just return the error code.
+ */
if (status != PIPE_ERROR_AGAIN ||
- (filp->f_flags & O_NONBLOCK) != 0) {
+ (filp->f_flags & O_NONBLOCK) != 0) {
ret = goldfish_pipe_error_convert(status);
break;
}
- /* We will have to wait until more data/space is available.
- * First, mark the pipe as waiting for a specific wake signal.
- */
+ /*
+ * The backend blocked the read/write, wait until the backend
+ * tells us it's ready to process more data.
+ */
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 */
- goldfish_cmd(pipe, CMD_WAKE_ON_WRITE + cmd_offset);
+ goldfish_cmd(pipe,
+ is_write ? CMD_WAKE_ON_WRITE : CMD_WAKE_ON_READ);
/* Unlock the pipe, then wait for the wake signal */
mutex_unlock(&pipe->lock);
@@ -388,12 +388,13 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
/* Try to re-acquire the lock */
if (mutex_lock_interruptible(&pipe->lock))
return -ERESTARTSYS;
-
- /* Try the transfer again */
- continue;
}
mutex_unlock(&pipe->lock);
- return ret;
+
+ if (ret < 0)
+ return ret;
+ else
+ return count;
}
static ssize_t goldfish_pipe_read(struct file *filp, char __user *buffer,
@@ -446,10 +447,11 @@ static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id)
unsigned long irq_flags;
int count = 0;
- /* We're going to read from the emulator a list of (channel,flags)
- * pairs corresponding to the wake events that occured on each
- * blocked pipe (i.e. channel).
- */
+ /*
+ * We're going to read from the emulator a list of (channel,flags)
+ * pairs corresponding to the wake events that occured on each
+ * blocked pipe (i.e. channel).
+ */
spin_lock_irqsave(&dev->lock, irq_flags);
for (;;) {
/* First read the channel, 0 means the end of the list */
@@ -514,6 +516,8 @@ static int goldfish_pipe_open(struct inode *inode, struct file *file)
pipe->dev = dev;
mutex_init(&pipe->lock);
+ DPRINT("%s: call. pipe_dev pipe_dev=0x%lx new_pipe_addr=0x%lx file=0x%lx\n", __FUNCTION__, pipe_dev, pipe, file);
+ // spin lock init, write head of list, i guess
init_waitqueue_head(&pipe->wake_queue);
/*
@@ -536,6 +540,7 @@ static int goldfish_pipe_release(struct inode *inode, struct file *filp)
{
struct goldfish_pipe *pipe = filp->private_data;
+ DPRINT("%s: call. pipe=0x%lx file=0x%lx\n", __FUNCTION__, pipe, filp);
/* The guest is closing the channel, so tell the emulator right now */
goldfish_cmd(pipe, CMD_CLOSE);
kfree(pipe);
@@ -552,77 +557,33 @@ static const struct file_operations goldfish_pipe_fops = {
.release = goldfish_pipe_release,
};
-static struct miscdevice goldfish_pipe_device = {
+static struct miscdevice goldfish_pipe_dev = {
.minor = MISC_DYNAMIC_MINOR,
.name = "goldfish_pipe",
.fops = &goldfish_pipe_fops,
};
-static int goldfish_pipe_probe(struct platform_device *pdev)
+int goldfish_pipe_device_init_v1(struct platform_device *pdev)
{
- int err;
- struct resource *r;
struct goldfish_pipe_dev *dev = pipe_dev;
-
- /* 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;
-
- err = devm_request_irq(&pdev->dev, dev->irq, goldfish_pipe_interrupt,
+ 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\n");
- goto error;
+ dev_err(&pdev->dev, "unable to allocate IRQ for v1\n");
+ return err;
}
- err = misc_register(&goldfish_pipe_device);
+ err = misc_register(&goldfish_pipe_dev);
if (err) {
- dev_err(&pdev->dev, "unable to register device\n");
- goto error;
+ dev_err(&pdev->dev, "unable to register v1 device\n");
+ return err;
}
+
setup_access_params_addr(pdev, dev);
return 0;
-
-error:
- dev->base = NULL;
- return err;
}
-static int goldfish_pipe_remove(struct platform_device *pdev)
+void goldfish_pipe_device_deinit_v1(struct platform_device *pdev)
{
- struct goldfish_pipe_dev *dev = pipe_dev;
- misc_deregister(&goldfish_pipe_device);
- dev->base = NULL;
- return 0;
+ misc_deregister(&goldfish_pipe_dev);
}
-
-static struct platform_driver goldfish_pipe = {
- .probe = goldfish_pipe_probe,
- .remove = goldfish_pipe_remove,
- .driver = {
- .name = "goldfish_pipe"
- }
-};
-
-module_platform_driver(goldfish_pipe);
-MODULE_AUTHOR("David Turner <digit@google.com>");
-MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-25 09:43:42 +0000