staging: add bcm2708 vchiq driver

Signed-off-by: popcornmix <popcornmix@gmail.com>

vchiq: create_pagelist copes with vmalloc memory

Signed-off-by: Daniel Stone <daniels@collabora.com>

vchiq: fix the shim message release

Signed-off-by: Daniel Stone <daniels@collabora.com>

vchiq: export additional symbols

Signed-off-by: Daniel Stone <daniels@collabora.com>

VCHIQ: Make service closure fully synchronous (drv)

This is one half of a two-part patch, the other half of which is to
the vchiq_lib user library. With these patches, calls to
vchiq_close_service and vchiq_remove_service won't return until any
associated callbacks have been delivered to the callback thread.

VCHIQ: Add per-service tracing

The new service option VCHIQ_SERVICE_OPTION_TRACE is a boolean that
toggles tracing for the specified service.

This commit also introduces vchi_service_set_option and the associated
option VCHI_SERVICE_OPTION_TRACE.

vchiq: Make the synchronous-CLOSE logic more tolerant

vchiq: Move logging control into debugfs

vchiq: Take care of a corner case tickled by VCSM

Closing a connection that isn't fully open requires care, since one
side does not know the other side's port number. Code was present to
handle the case where a CLOSE is sent immediately after an OPEN, i.e.
before the OPENACK has been received, but this was incorrectly being
used when an OPEN from a client using port 0 was rejected.

(In the observed failure, the host was attempting to use the VCSM
service, which isn't present in the 'cutdown' firmware. The failure
was intermittent because sometimes the keepalive service would
grab port 0.)

This case can be distinguished because the client's remoteport will
still be VCHIQ_PORT_FREE, and the srvstate will be OPENING. Either
condition is sufficient to differentiate it from the special case
described above.

vchiq: Avoid high load when blocked and unkillable

vchiq: Include SIGSTOP and SIGCONT in list of signals not-masked by vchiq to allow gdb to work

vchiq_arm: Complete support for SYNCHRONOUS mode

vchiq: Remove inline from suspend/resume

vchiq: Allocation does not need to be atomic

vchiq: Fix wrong condition check

The log level is checked from within the log call. Remove the check in the call.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>

BCM270x: Add vchiq device to platform file and Device Tree

Prepare to turn the vchiq module into a driver.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

bcm2708: vchiq: Add Device Tree support

Turn vchiq into a driver and stop hardcoding resources.
Use devm_* functions in probe path to simplify cleanup.
A global variable is used to hold the register address. This is done
to keep this patch as small as possible.
Also make available on ARCH_BCM2835.
Based on work by Lubomir Rintel.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

vchiq: Change logging level for inbound data

vchiq_arm: Two cacheing fixes

1) Make fragment size vary with cache line size
Without this patch, non-cache-line-aligned transfers may corrupt
(or be corrupted by) adjacent data structures.

Both ARM and VC need to be updated to enable this feature. This is
ensured by having the loader apply a new DT parameter -
cache-line-size. The existence of this parameter guarantees that the
kernel is capable, and the parameter will only be modified from the
safe default if the loader is capable.

2) Flush/invalidate vmalloc'd memory, and invalidate after reads

vchiq: fix NULL pointer dereference when closing driver

The following code run as root will cause a null pointer dereference oops:

        int fd = open("/dev/vc-cma", O_RDONLY);
        if (fd < 0)
                err(1, "open failed");
        (void)close(fd);

[ 1704.877721] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 1704.877725] pgd = b899c000
[ 1704.877736] [00000000] *pgd=37fab831, *pte=00000000, *ppte=00000000
[ 1704.877748] Internal error: Oops: 817 [#1] PREEMPT SMP ARM
[ 1704.877765] Modules linked in: evdev i2c_bcm2708 uio_pdrv_genirq uio
[ 1704.877774] CPU: 2 PID: 3656 Comm: stress-ng-fstat Not tainted 3.19.1-12-generic-bcm2709 #12-Ubuntu
[ 1704.877777] Hardware name: BCM2709
[ 1704.877783] task: b8ab9b00 ti: b7e68000 task.ti: b7e68000
[ 1704.877798] PC is at __down_interruptible+0x50/0xec
[ 1704.877806] LR is at down_interruptible+0x5c/0x68
[ 1704.877813] pc : [<80630ee8>]    lr : [<800704b0>]    psr: 60080093
sp : b7e69e50  ip : b7e69e88  fp : b7e69e84
[ 1704.877817] r10: b88123c8  r9 : 00000010  r8 : 00000001
[ 1704.877822] r7 : b8ab9b00  r6 : 7fffffff  r5 : 80a1cc34  r4 : 80a1cc34
[ 1704.877826] r3 : b7e69e50  r2 : 00000000  r1 : 00000000  r0 : 80a1cc34
[ 1704.877833] Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment user
[ 1704.877838] Control: 10c5387d  Table: 3899c06a  DAC: 00000015
[ 1704.877843] Process do-oops (pid: 3656, stack limit = 0xb7e68238)
[ 1704.877848] Stack: (0xb7e69e50 to 0xb7e6a000)
[ 1704.877856] 9e40:                                     80a1cc3c 00000000 00000010 b88123c8
[ 1704.877865] 9e60: b7e69e84 80a1cc34 fff9fee9 ffffffff b7e68000 00000009 b7e69ea4 b7e69e88
[ 1704.877874] 9e80: 800704b0 80630ea4 fff9fee9 60080013 80a1cc28 fff9fee9 b7e69edc b7e69ea8
[ 1704.877884] 9ea0: 8040f558 80070460 fff9fee9 ffffffff 00000000 00000000 00000009 80a1cb7c
[ 1704.877893] 9ec0: 00000000 80a1cb7c 00000000 00000010 b7e69ef4 b7e69ee0 803e1ba4 8040f514
[ 1704.877902] 9ee0: 00000e48 80a1cb7c b7e69f14 b7e69ef8 803e1c9c 803e1b74 b88123c0 b92acb18
[ 1704.877911] 9f00: b8812790 b8d815d8 b7e69f24 b7e69f18 803e2250 803e1bc8 b7e69f5c b7e69f28
[ 1704.877921] 9f20: 80167bac 803e222c 00000000 00000000 b7e69f54 b8ab9ffc 00000000 8098c794
[ 1704.877930] 9f40: b8ab9b00 8000efc4 b7e68000 00000000 b7e69f6c b7e69f60 80167d6c 80167b28
[ 1704.877939] 9f60: b7e69f8c b7e69f70 80047d38 80167d60 b7e68000 b7e68010 8000efc4 b7e69fb0
[ 1704.877949] 9f80: b7e69fac b7e69f90 80012820 80047c84 01155490 011549a8 00000001 00000006
[ 1704.877957] 9fa0: 00000000 b7e69fb0 8000ee5c 80012790 00000000 353d8c0f 7efc4308 00000000
[ 1704.877966] 9fc0: 01155490 011549a8 00000001 00000006 00000000 00000000 76cf3ba0 00000003
[ 1704.877975] 9fe0: 00000000 7efc42e4 0002272f 76e2ed66 60080030 00000003 00000000 00000000
[ 1704.877998] [<80630ee8>] (__down_interruptible) from [<800704b0>] (down_interruptible+0x5c/0x68)
[ 1704.878015] [<800704b0>] (down_interruptible) from [<8040f558>] (vchiu_queue_push+0x50/0xd8)
[ 1704.878032] [<8040f558>] (vchiu_queue_push) from [<803e1ba4>] (send_worker_msg+0x3c/0x54)
[ 1704.878045] [<803e1ba4>] (send_worker_msg) from [<803e1c9c>] (vc_cma_set_reserve+0xe0/0x1c4)
[ 1704.878057] [<803e1c9c>] (vc_cma_set_reserve) from [<803e2250>] (vc_cma_release+0x30/0x38)
[ 1704.878069] [<803e2250>] (vc_cma_release) from [<80167bac>] (__fput+0x90/0x1e0)
[ 1704.878082] [<80167bac>] (__fput) from [<80167d6c>] (____fput+0x18/0x1c)
[ 1704.878094] [<80167d6c>] (____fput) from [<80047d38>] (task_work_run+0xc0/0xf8)
[ 1704.878109] [<80047d38>] (task_work_run) from [<80012820>] (do_work_pending+0x9c/0xc4)
[ 1704.878123] [<80012820>] (do_work_pending) from [<8000ee5c>] (work_pending+0xc/0x20)
[ 1704.878133] Code: e50b1034 e3a01000 e50b2030 e580300c (e5823000)

..the fix is to ensure that we have actually initialized the queue before we attempt
to push any items onto it.  This occurs if we do an open() followed by a close() without
any activity in between.

Signed-off-by: Colin Ian King <colin.king@canonical.com>

vchiq_arm: Sort out the vmalloc case

See: https://github.com/raspberrypi/linux/issues/1055

vchiq: hack: Add include depecated dma include file

[gregkh] added dependancy on CONFIG_BROKEN to make things sane for now.

Cc: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 586 insertions, 0 deletions

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
new file mode 100644
index 000000000000..c29040fdf9a7
--- /dev/null
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
@@ -0,0 +1,586 @@
+/**
+ * Copyright (c) 2010-2012 Broadcom. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The names of the above-listed copyright holders may not be used
+ *    to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2, as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/pagemap.h>
+#include <linux/dma-mapping.h>
+#include <linux/version.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/uaccess.h>
+#include <linux/of.h>
+#include <asm/pgtable.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define dmac_map_area			__glue(_CACHE,_dma_map_area)
+#define dmac_unmap_area 		__glue(_CACHE,_dma_unmap_area)
+
+extern void dmac_map_area(const void *, size_t, int);
+extern void dmac_unmap_area(const void *, size_t, int);
+
+#define TOTAL_SLOTS (VCHIQ_SLOT_ZERO_SLOTS + 2 * 32)
+
+#define VCHIQ_ARM_ADDRESS(x) ((void *)((char *)x + g_virt_to_bus_offset))
+
+#include "vchiq_arm.h"
+#include "vchiq_2835.h"
+#include "vchiq_connected.h"
+#include "vchiq_killable.h"
+
+#define MAX_FRAGMENTS (VCHIQ_NUM_CURRENT_BULKS * 2)
+
+#define BELL0	0x00
+#define BELL2	0x08
+
+typedef struct vchiq_2835_state_struct {
+   int inited;
+   VCHIQ_ARM_STATE_T arm_state;
+} VCHIQ_2835_ARM_STATE_T;
+
+static void __iomem *g_regs;
+static unsigned int g_cache_line_size = sizeof(CACHE_LINE_SIZE);
+static unsigned int g_fragments_size;
+static char *g_fragments_base;
+static char *g_free_fragments;
+static struct semaphore g_free_fragments_sema;
+static unsigned long g_virt_to_bus_offset;
+
+extern int vchiq_arm_log_level;
+
+static DEFINE_SEMAPHORE(g_free_fragments_mutex);
+
+static irqreturn_t
+vchiq_doorbell_irq(int irq, void *dev_id);
+
+static int
+create_pagelist(char __user *buf, size_t count, unsigned short type,
+                struct task_struct *task, PAGELIST_T ** ppagelist);
+
+static void
+free_pagelist(PAGELIST_T *pagelist, int actual);
+
+int vchiq_platform_init(struct platform_device *pdev, VCHIQ_STATE_T *state)
+{
+	struct device *dev = &pdev->dev;
+	struct rpi_firmware *fw = platform_get_drvdata(pdev);
+	VCHIQ_SLOT_ZERO_T *vchiq_slot_zero;
+	struct resource *res;
+	void *slot_mem;
+	dma_addr_t slot_phys;
+	u32 channelbase;
+	int slot_mem_size, frag_mem_size;
+	int err, irq, i;
+
+	g_virt_to_bus_offset = virt_to_dma(dev, (void *)0);
+
+	(void)of_property_read_u32(dev->of_node, "cache-line-size",
+				   &g_cache_line_size);
+	g_fragments_size = 2 * g_cache_line_size;
+
+	/* Allocate space for the channels in coherent memory */
+	slot_mem_size = PAGE_ALIGN(TOTAL_SLOTS * VCHIQ_SLOT_SIZE);
+	frag_mem_size = PAGE_ALIGN(g_fragments_size * MAX_FRAGMENTS);
+
+	slot_mem = dmam_alloc_coherent(dev, slot_mem_size + frag_mem_size,
+				       &slot_phys, GFP_KERNEL);
+	if (!slot_mem) {
+		dev_err(dev, "could not allocate DMA memory\n");
+		return -ENOMEM;
+	}
+
+	WARN_ON(((int)slot_mem & (PAGE_SIZE - 1)) != 0);
+
+	vchiq_slot_zero = vchiq_init_slots(slot_mem, slot_mem_size);
+	if (!vchiq_slot_zero)
+		return -EINVAL;
+
+	vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_OFFSET_IDX] =
+		(int)slot_phys + slot_mem_size;
+	vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_COUNT_IDX] =
+		MAX_FRAGMENTS;
+
+	g_fragments_base = (char *)slot_mem + slot_mem_size;
+	slot_mem_size += frag_mem_size;
+
+	g_free_fragments = g_fragments_base;
+	for (i = 0; i < (MAX_FRAGMENTS - 1); i++) {
+		*(char **)&g_fragments_base[i*g_fragments_size] =
+			&g_fragments_base[(i + 1)*g_fragments_size];
+	}
+	*(char **)&g_fragments_base[i * g_fragments_size] = NULL;
+	sema_init(&g_free_fragments_sema, MAX_FRAGMENTS);
+
+	if (vchiq_init_state(state, vchiq_slot_zero, 0) != VCHIQ_SUCCESS)
+		return -EINVAL;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	g_regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(g_regs))
+		return PTR_ERR(g_regs);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0) {
+		dev_err(dev, "failed to get IRQ\n");
+		return irq;
+	}
+
+	err = devm_request_irq(dev, irq, vchiq_doorbell_irq, IRQF_IRQPOLL,
+			       "VCHIQ doorbell", state);
+	if (err) {
+		dev_err(dev, "failed to register irq=%d\n", irq);
+		return err;
+	}
+
+	/* Send the base address of the slots to VideoCore */
+	channelbase = slot_phys;
+	err = rpi_firmware_property(fw, RPI_FIRMWARE_VCHIQ_INIT,
+				    &channelbase, sizeof(channelbase));
+	if (err || channelbase) {
+		dev_err(dev, "failed to set channelbase\n");
+		return err ? : -ENXIO;
+	}
+
+	vchiq_log_info(vchiq_arm_log_level,
+		"vchiq_init - done (slots %x, phys %pad)",
+		(unsigned int)vchiq_slot_zero, &slot_phys);
+
+	vchiq_call_connected_callbacks();
+
+   return 0;
+}
+
+VCHIQ_STATUS_T
+vchiq_platform_init_state(VCHIQ_STATE_T *state)
+{
+   VCHIQ_STATUS_T status = VCHIQ_SUCCESS;
+   state->platform_state = kzalloc(sizeof(VCHIQ_2835_ARM_STATE_T), GFP_KERNEL);
+   ((VCHIQ_2835_ARM_STATE_T*)state->platform_state)->inited = 1;
+   status = vchiq_arm_init_state(state, &((VCHIQ_2835_ARM_STATE_T*)state->platform_state)->arm_state);
+   if(status != VCHIQ_SUCCESS)
+   {
+      ((VCHIQ_2835_ARM_STATE_T*)state->platform_state)->inited = 0;
+   }
+   return status;
+}
+
+VCHIQ_ARM_STATE_T*
+vchiq_platform_get_arm_state(VCHIQ_STATE_T *state)
+{
+   if(!((VCHIQ_2835_ARM_STATE_T*)state->platform_state)->inited)
+   {
+      BUG();
+   }
+   return &((VCHIQ_2835_ARM_STATE_T*)state->platform_state)->arm_state;
+}
+
+void
+remote_event_signal(REMOTE_EVENT_T *event)
+{
+	wmb();
+
+	event->fired = 1;
+
+	dsb();         /* data barrier operation */
+
+	if (event->armed)
+		writel(0, g_regs + BELL2); /* trigger vc interrupt */
+}
+
+int
+vchiq_copy_from_user(void *dst, const void *src, int size)
+{
+	if ((uint32_t)src < TASK_SIZE) {
+		return copy_from_user(dst, src, size);
+	} else {
+		memcpy(dst, src, size);
+		return 0;
+	}
+}
+
+VCHIQ_STATUS_T
+vchiq_prepare_bulk_data(VCHIQ_BULK_T *bulk, VCHI_MEM_HANDLE_T memhandle,
+	void *offset, int size, int dir)
+{
+	PAGELIST_T *pagelist;
+	int ret;
+
+	WARN_ON(memhandle != VCHI_MEM_HANDLE_INVALID);
+
+	ret = create_pagelist((char __user *)offset, size,
+			(dir == VCHIQ_BULK_RECEIVE)
+			? PAGELIST_READ
+			: PAGELIST_WRITE,
+			current,
+			&pagelist);
+	if (ret != 0)
+		return VCHIQ_ERROR;
+
+	bulk->handle = memhandle;
+	bulk->data = VCHIQ_ARM_ADDRESS(pagelist);
+
+	/* Store the pagelist address in remote_data, which isn't used by the
+	   slave. */
+	bulk->remote_data = pagelist;
+
+	return VCHIQ_SUCCESS;
+}
+
+void
+vchiq_complete_bulk(VCHIQ_BULK_T *bulk)
+{
+	if (bulk && bulk->remote_data && bulk->actual)
+		free_pagelist((PAGELIST_T *)bulk->remote_data, bulk->actual);
+}
+
+void
+vchiq_transfer_bulk(VCHIQ_BULK_T *bulk)
+{
+	/*
+	 * This should only be called on the master (VideoCore) side, but
+	 * provide an implementation to avoid the need for ifdefery.
+	 */
+	BUG();
+}
+
+void
+vchiq_dump_platform_state(void *dump_context)
+{
+	char buf[80];
+	int len;
+	len = snprintf(buf, sizeof(buf),
+		"  Platform: 2835 (VC master)");
+	vchiq_dump(dump_context, buf, len + 1);
+}
+
+VCHIQ_STATUS_T
+vchiq_platform_suspend(VCHIQ_STATE_T *state)
+{
+   return VCHIQ_ERROR;
+}
+
+VCHIQ_STATUS_T
+vchiq_platform_resume(VCHIQ_STATE_T *state)
+{
+   return VCHIQ_SUCCESS;
+}
+
+void
+vchiq_platform_paused(VCHIQ_STATE_T *state)
+{
+}
+
+void
+vchiq_platform_resumed(VCHIQ_STATE_T *state)
+{
+}
+
+int
+vchiq_platform_videocore_wanted(VCHIQ_STATE_T* state)
+{
+   return 1; // autosuspend not supported - videocore always wanted
+}
+
+int
+vchiq_platform_use_suspend_timer(void)
+{
+   return 0;
+}
+void
+vchiq_dump_platform_use_state(VCHIQ_STATE_T *state)
+{
+	vchiq_log_info(vchiq_arm_log_level, "Suspend timer not in use");
+}
+void
+vchiq_platform_handle_timeout(VCHIQ_STATE_T *state)
+{
+	(void)state;
+}
+/*
+ * Local functions
+ */
+
+static irqreturn_t
+vchiq_doorbell_irq(int irq, void *dev_id)
+{
+	VCHIQ_STATE_T *state = dev_id;
+	irqreturn_t ret = IRQ_NONE;
+	unsigned int status;
+
+	/* Read (and clear) the doorbell */
+	status = readl(g_regs + BELL0);
+
+	if (status & 0x4) {  /* Was the doorbell rung? */
+		remote_event_pollall(state);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+/* There is a potential problem with partial cache lines (pages?)
+** at the ends of the block when reading. If the CPU accessed anything in
+** the same line (page?) then it may have pulled old data into the cache,
+** obscuring the new data underneath. We can solve this by transferring the
+** partial cache lines separately, and allowing the ARM to copy into the
+** cached area.
+
+** N.B. This implementation plays slightly fast and loose with the Linux
+** driver programming rules, e.g. its use of dmac_map_area instead of
+** dma_map_single, but it isn't a multi-platform driver and it benefits
+** from increased speed as a result.
+*/
+
+static int
+create_pagelist(char __user *buf, size_t count, unsigned short type,
+	struct task_struct *task, PAGELIST_T ** ppagelist)
+{
+	PAGELIST_T *pagelist;
+	struct page **pages;
+	unsigned long *addrs;
+	unsigned int num_pages, offset, i;
+	char *addr, *base_addr, *next_addr;
+	int run, addridx, actual_pages;
+        unsigned long *need_release;
+
+	offset = (unsigned int)buf & (PAGE_SIZE - 1);
+	num_pages = (count + offset + PAGE_SIZE - 1) / PAGE_SIZE;
+
+	*ppagelist = NULL;
+
+	/* Allocate enough storage to hold the page pointers and the page
+	** list
+	*/
+	pagelist = kmalloc(sizeof(PAGELIST_T) +
+                           (num_pages * sizeof(unsigned long)) +
+                           sizeof(unsigned long) +
+                           (num_pages * sizeof(pages[0])),
+                           GFP_KERNEL);
+
+	vchiq_log_trace(vchiq_arm_log_level,
+		"create_pagelist - %x", (unsigned int)pagelist);
+	if (!pagelist)
+		return -ENOMEM;
+
+	addrs = pagelist->addrs;
+        need_release = (unsigned long *)(addrs + num_pages);
+	pages = (struct page **)(addrs + num_pages + 1);
+
+	if (is_vmalloc_addr(buf)) {
+		int dir = (type == PAGELIST_WRITE) ?
+			DMA_TO_DEVICE : DMA_FROM_DEVICE;
+		unsigned long length = count;
+		unsigned int off = offset;
+
+		for (actual_pages = 0; actual_pages < num_pages;
+		     actual_pages++) {
+			struct page *pg = vmalloc_to_page(buf + (actual_pages *
+								 PAGE_SIZE));
+			size_t bytes = PAGE_SIZE - off;
+
+			if (bytes > length)
+				bytes = length;
+			pages[actual_pages] = pg;
+			dmac_map_area(page_address(pg) + off, bytes, dir);
+			length -= bytes;
+			off = 0;
+		}
+		*need_release = 0; /* do not try and release vmalloc pages */
+	} else {
+		down_read(&task->mm->mmap_sem);
+		actual_pages = get_user_pages(task, task->mm,
+				          (unsigned long)buf & ~(PAGE_SIZE - 1),
+					  num_pages,
+					  (type == PAGELIST_READ) /*Write */ ,
+					  0 /*Force */ ,
+					  pages,
+					  NULL /*vmas */);
+		up_read(&task->mm->mmap_sem);
+
+		if (actual_pages != num_pages) {
+			vchiq_log_info(vchiq_arm_log_level,
+				       "create_pagelist - only %d/%d pages locked",
+				       actual_pages,
+				       num_pages);
+
+			/* This is probably due to the process being killed */
+			while (actual_pages > 0)
+			{
+				actual_pages--;
+				page_cache_release(pages[actual_pages]);
+			}
+			kfree(pagelist);
+			if (actual_pages == 0)
+				actual_pages = -ENOMEM;
+			return actual_pages;
+		}
+		*need_release = 1; /* release user pages */
+	}
+
+	pagelist->length = count;
+	pagelist->type = type;
+	pagelist->offset = offset;
+
+	/* Group the pages into runs of contiguous pages */
+
+	base_addr = VCHIQ_ARM_ADDRESS(page_address(pages[0]));
+	next_addr = base_addr + PAGE_SIZE;
+	addridx = 0;
+	run = 0;
+
+	for (i = 1; i < num_pages; i++) {
+		addr = VCHIQ_ARM_ADDRESS(page_address(pages[i]));
+		if ((addr == next_addr) && (run < (PAGE_SIZE - 1))) {
+			next_addr += PAGE_SIZE;
+			run++;
+		} else {
+			addrs[addridx] = (unsigned long)base_addr + run;
+			addridx++;
+			base_addr = addr;
+			next_addr = addr + PAGE_SIZE;
+			run = 0;
+		}
+	}
+
+	addrs[addridx] = (unsigned long)base_addr + run;
+	addridx++;
+
+	/* Partial cache lines (fragments) require special measures */
+	if ((type == PAGELIST_READ) &&
+		((pagelist->offset & (g_cache_line_size - 1)) ||
+		((pagelist->offset + pagelist->length) &
+		(g_cache_line_size - 1)))) {
+		char *fragments;
+
+		if (down_interruptible(&g_free_fragments_sema) != 0) {
+			kfree(pagelist);
+			return -EINTR;
+		}
+
+		WARN_ON(g_free_fragments == NULL);
+
+		down(&g_free_fragments_mutex);
+		fragments = g_free_fragments;
+		WARN_ON(fragments == NULL);
+		g_free_fragments = *(char **) g_free_fragments;
+		up(&g_free_fragments_mutex);
+		pagelist->type = PAGELIST_READ_WITH_FRAGMENTS +
+			(fragments - g_fragments_base) / g_fragments_size;
+	}
+
+	dmac_flush_range(pagelist, addrs + num_pages);
+
+	*ppagelist = pagelist;
+
+	return 0;
+}
+
+static void
+free_pagelist(PAGELIST_T *pagelist, int actual)
+{
+        unsigned long *need_release;
+	struct page **pages;
+	unsigned int num_pages, i;
+
+	vchiq_log_trace(vchiq_arm_log_level,
+		"free_pagelist - %x, %d", (unsigned int)pagelist, actual);
+
+	num_pages =
+		(pagelist->length + pagelist->offset + PAGE_SIZE - 1) /
+		PAGE_SIZE;
+
+        need_release = (unsigned long *)(pagelist->addrs + num_pages);
+	pages = (struct page **)(pagelist->addrs + num_pages + 1);
+
+	/* Deal with any partial cache lines (fragments) */
+	if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS) {
+		char *fragments = g_fragments_base +
+			(pagelist->type - PAGELIST_READ_WITH_FRAGMENTS) *
+			g_fragments_size;
+		int head_bytes, tail_bytes;
+		head_bytes = (g_cache_line_size - pagelist->offset) &
+			(g_cache_line_size - 1);
+		tail_bytes = (pagelist->offset + actual) &
+			(g_cache_line_size - 1);
+
+		if ((actual >= 0) && (head_bytes != 0)) {
+			if (head_bytes > actual)
+				head_bytes = actual;
+
+			memcpy((char *)page_address(pages[0]) +
+				pagelist->offset,
+				fragments,
+				head_bytes);
+		}
+		if ((actual >= 0) && (head_bytes < actual) &&
+			(tail_bytes != 0)) {
+			memcpy((char *)page_address(pages[num_pages - 1]) +
+				((pagelist->offset + actual) &
+				(PAGE_SIZE - 1) & ~(g_cache_line_size - 1)),
+				fragments + g_cache_line_size,
+				tail_bytes);
+		}
+
+		down(&g_free_fragments_mutex);
+		*(char **)fragments = g_free_fragments;
+		g_free_fragments = fragments;
+		up(&g_free_fragments_mutex);
+		up(&g_free_fragments_sema);
+	}
+
+	if (*need_release) {
+		unsigned int length = pagelist->length;
+		unsigned int offset = pagelist->offset;
+
+		for (i = 0; i < num_pages; i++) {
+			struct page *pg = pages[i];
+
+			if (pagelist->type != PAGELIST_WRITE) {
+				unsigned int bytes = PAGE_SIZE - offset;
+
+				if (bytes > length)
+					bytes = length;
+				dmac_unmap_area(page_address(pg) + offset,
+						bytes, DMA_FROM_DEVICE);
+				length -= bytes;
+				offset = 0;
+				set_page_dirty(pg);
+			}
+			page_cache_release(pg);
+		}
+	}
+
+	kfree(pagelist);
+}