sh/maple: clean maple bus code
This patch cleans up the handling of the maple bus queue to remove
the risk of races when adding packets. It also removes references to the
redundant connect and disconnect functions.
Signed-off-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/drivers/sh/maple/maple.c b/drivers/sh/maple/maple.c
index 617efb1..be97789 100644
--- a/drivers/sh/maple/maple.c
+++ b/drivers/sh/maple/maple.c
@@ -24,13 +24,12 @@
#include <linux/slab.h>
#include <linux/maple.h>
#include <linux/dma-mapping.h>
+#include <linux/delay.h>
#include <asm/cacheflush.h>
#include <asm/dma.h>
#include <asm/io.h>
-#include <asm/mach/dma.h>
-#include <asm/mach/sysasic.h>
-#include <asm/mach/maple.h>
-#include <linux/delay.h>
+#include <mach/dma.h>
+#include <mach/sysasic.h>
MODULE_AUTHOR("Yaegshi Takeshi, Paul Mundt, M.R. Brown, Adrian McMenamin");
MODULE_DESCRIPTION("Maple bus driver for Dreamcast");
@@ -46,14 +45,15 @@
static LIST_HEAD(maple_waitq);
static LIST_HEAD(maple_sentq);
-static DEFINE_MUTEX(maple_list_lock);
+/* mutex to protect queue of waiting packets */
+static DEFINE_MUTEX(maple_wlist_lock);
static struct maple_driver maple_dummy_driver;
static struct device maple_bus;
static int subdevice_map[MAPLE_PORTS];
static unsigned long *maple_sendbuf, *maple_sendptr, *maple_lastptr;
static unsigned long maple_pnp_time;
-static int started, scanning, liststatus, fullscan;
+static int started, scanning, fullscan;
static struct kmem_cache *maple_queue_cache;
struct maple_device_specify {
@@ -129,35 +129,124 @@
kfree(mdev);
}
-/**
+/*
* maple_add_packet - add a single instruction to the queue
- * @mq: instruction to add to waiting queue
+ * @mdev - maple device
+ * @function - function on device being queried
+ * @command - maple command to add
+ * @length - length of command string (in 32 bit words)
+ * @data - remainder of command string
*/
-void maple_add_packet(struct mapleq *mq)
+int maple_add_packet(struct maple_device *mdev, u32 function, u32 command,
+ size_t length, void *data)
{
- mutex_lock(&maple_list_lock);
- list_add(&mq->list, &maple_waitq);
- mutex_unlock(&maple_list_lock);
+ int locking, ret = 0;
+ void *sendbuf = NULL;
+
+ mutex_lock(&maple_wlist_lock);
+ /* bounce if device already locked */
+ locking = mutex_is_locked(&mdev->mq->mutex);
+ if (locking) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ mutex_lock(&mdev->mq->mutex);
+
+ if (length) {
+ sendbuf = kmalloc(length * 4, GFP_KERNEL);
+ if (!sendbuf) {
+ mutex_unlock(&mdev->mq->mutex);
+ ret = -ENOMEM;
+ goto out;
+ }
+ ((__be32 *)sendbuf)[0] = cpu_to_be32(function);
+ }
+
+ mdev->mq->command = command;
+ mdev->mq->length = length;
+ if (length > 1)
+ memcpy(sendbuf + 4, data, (length - 1) * 4);
+ mdev->mq->sendbuf = sendbuf;
+
+ list_add(&mdev->mq->list, &maple_waitq);
+out:
+ mutex_unlock(&maple_wlist_lock);
+ return ret;
}
EXPORT_SYMBOL_GPL(maple_add_packet);
+/*
+ * maple_add_packet_sleeps - add a single instruction to the queue
+ * - waits for lock to be free
+ * @mdev - maple device
+ * @function - function on device being queried
+ * @command - maple command to add
+ * @length - length of command string (in 32 bit words)
+ * @data - remainder of command string
+ */
+int maple_add_packet_sleeps(struct maple_device *mdev, u32 function,
+ u32 command, size_t length, void *data)
+{
+ int locking, ret = 0;
+ void *sendbuf = NULL;
+
+ locking = mutex_lock_interruptible(&mdev->mq->mutex);
+ if (locking) {
+ ret = -EIO;
+ goto out;
+ }
+
+ if (length) {
+ sendbuf = kmalloc(length * 4, GFP_KERNEL);
+ if (!sendbuf) {
+ mutex_unlock(&mdev->mq->mutex);
+ ret = -ENOMEM;
+ goto out;
+ }
+ ((__be32 *)sendbuf)[0] = cpu_to_be32(function);
+ }
+
+ mdev->mq->command = command;
+ mdev->mq->length = length;
+ if (length > 1)
+ memcpy(sendbuf + 4, data, (length - 1) * 4);
+ mdev->mq->sendbuf = sendbuf;
+
+ mutex_lock(&maple_wlist_lock);
+ list_add(&mdev->mq->list, &maple_waitq);
+ mutex_unlock(&maple_wlist_lock);
+out:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(maple_add_packet_sleeps);
+
static struct mapleq *maple_allocq(struct maple_device *mdev)
{
struct mapleq *mq;
mq = kmalloc(sizeof(*mq), GFP_KERNEL);
if (!mq)
- return NULL;
+ goto failed_nomem;
mq->dev = mdev;
mq->recvbufdcsp = kmem_cache_zalloc(maple_queue_cache, GFP_KERNEL);
mq->recvbuf = (void *) P2SEGADDR(mq->recvbufdcsp);
- if (!mq->recvbuf) {
- kfree(mq);
- return NULL;
- }
+ if (!mq->recvbuf)
+ goto failed_p2;
+ /*
+ * most devices do not need the mutex - but
+ * anything that injects block reads or writes
+ * will rely on it
+ */
+ mutex_init(&mq->mutex);
return mq;
+
+failed_p2:
+ kfree(mq);
+failed_nomem:
+ return NULL;
}
static struct maple_device *maple_alloc_dev(int port, int unit)
@@ -178,7 +267,6 @@
}
mdev->dev.bus = &maple_bus_type;
mdev->dev.parent = &maple_bus;
- mdev->function = 0;
return mdev;
}
@@ -216,7 +304,6 @@
*maple_sendptr++ = PHYSADDR(mq->recvbuf);
*maple_sendptr++ =
mq->command | (to << 8) | (from << 16) | (len << 24);
-
while (len-- > 0)
*maple_sendptr++ = *lsendbuf++;
}
@@ -224,22 +311,27 @@
/* build up command queue */
static void maple_send(void)
{
- int i;
- int maple_packets;
+ int i, maple_packets = 0;
struct mapleq *mq, *nmq;
if (!list_empty(&maple_sentq))
return;
- if (list_empty(&maple_waitq) || !maple_dma_done())
+ mutex_lock(&maple_wlist_lock);
+ if (list_empty(&maple_waitq) || !maple_dma_done()) {
+ mutex_unlock(&maple_wlist_lock);
return;
- maple_packets = 0;
- maple_sendptr = maple_lastptr = maple_sendbuf;
+ }
+ mutex_unlock(&maple_wlist_lock);
+ maple_lastptr = maple_sendbuf;
+ maple_sendptr = maple_sendbuf;
+ mutex_lock(&maple_wlist_lock);
list_for_each_entry_safe(mq, nmq, &maple_waitq, list) {
maple_build_block(mq);
list_move(&mq->list, &maple_sentq);
if (maple_packets++ > MAPLE_MAXPACKETS)
break;
}
+ mutex_unlock(&maple_wlist_lock);
if (maple_packets > 0) {
for (i = 0; i < (1 << MAPLE_DMA_PAGES); i++)
dma_cache_sync(0, maple_sendbuf + i * PAGE_SIZE,
@@ -247,7 +339,8 @@
}
}
-static int attach_matching_maple_driver(struct device_driver *driver,
+/* check if there is a driver registered likely to match this device */
+static int check_matching_maple_driver(struct device_driver *driver,
void *devptr)
{
struct maple_driver *maple_drv;
@@ -255,12 +348,8 @@
mdev = devptr;
maple_drv = to_maple_driver(driver);
- if (mdev->devinfo.function & be32_to_cpu(maple_drv->function)) {
- if (maple_drv->connect(mdev) == 0) {
- mdev->driver = maple_drv;
- return 1;
- }
- }
+ if (mdev->devinfo.function & cpu_to_be32(maple_drv->function))
+ return 1;
return 0;
}
@@ -268,11 +357,6 @@
{
if (!mdev)
return;
- if (mdev->driver) {
- if (mdev->driver->disconnect)
- mdev->driver->disconnect(mdev);
- }
- mdev->driver = NULL;
device_unregister(&mdev->dev);
mdev = NULL;
}
@@ -328,8 +412,8 @@
mdev->port, mdev->unit, function);
matched =
- bus_for_each_drv(&maple_bus_type, NULL, mdev,
- attach_matching_maple_driver);
+ bus_for_each_drv(&maple_bus_type, NULL, mdev,
+ check_matching_maple_driver);
if (matched == 0) {
/* Driver does not exist yet */
@@ -373,45 +457,48 @@
static int setup_maple_commands(struct device *device, void *ignored)
{
+ int add;
struct maple_device *maple_dev = to_maple_dev(device);
if ((maple_dev->interval > 0)
&& time_after(jiffies, maple_dev->when)) {
- maple_dev->when = jiffies + maple_dev->interval;
- maple_dev->mq->command = MAPLE_COMMAND_GETCOND;
- maple_dev->mq->sendbuf = &maple_dev->function;
- maple_dev->mq->length = 1;
- maple_add_packet(maple_dev->mq);
- liststatus++;
+ /* bounce if we cannot lock */
+ add = maple_add_packet(maple_dev,
+ be32_to_cpu(maple_dev->devinfo.function),
+ MAPLE_COMMAND_GETCOND, 1, NULL);
+ if (!add)
+ maple_dev->when = jiffies + maple_dev->interval;
} else {
- if (time_after(jiffies, maple_pnp_time)) {
- maple_dev->mq->command = MAPLE_COMMAND_DEVINFO;
- maple_dev->mq->length = 0;
- maple_add_packet(maple_dev->mq);
- liststatus++;
- }
+ if (time_after(jiffies, maple_pnp_time))
+ /* This will also bounce */
+ maple_add_packet(maple_dev, 0,
+ MAPLE_COMMAND_DEVINFO, 0, NULL);
}
-
return 0;
}
/* VBLANK bottom half - implemented via workqueue */
static void maple_vblank_handler(struct work_struct *work)
{
- if (!maple_dma_done())
+ if (!list_empty(&maple_sentq) || !maple_dma_done())
return;
- if (!list_empty(&maple_sentq))
- return;
+
ctrl_outl(0, MAPLE_ENABLE);
- liststatus = 0;
+
bus_for_each_dev(&maple_bus_type, NULL, NULL,
setup_maple_commands);
+
if (time_after(jiffies, maple_pnp_time))
maple_pnp_time = jiffies + MAPLE_PNP_INTERVAL;
- if (liststatus && list_empty(&maple_sentq)) {
- INIT_LIST_HEAD(&maple_sentq);
+
+ mutex_lock(&maple_wlist_lock);
+ if (!list_empty(&maple_waitq) && list_empty(&maple_sentq)) {
+ mutex_unlock(&maple_wlist_lock);
maple_send();
+ } else {
+ mutex_unlock(&maple_wlist_lock);
}
+
maplebus_dma_reset();
}
@@ -422,8 +509,8 @@
struct maple_device *mdev_add;
struct maple_device_specify ds;
+ ds.port = mdev->port;
for (k = 0; k < 5; k++) {
- ds.port = mdev->port;
ds.unit = k + 1;
retval =
bus_for_each_dev(&maple_bus_type, NULL, &ds,
@@ -437,9 +524,9 @@
mdev_add = maple_alloc_dev(mdev->port, k + 1);
if (!mdev_add)
return;
- mdev_add->mq->command = MAPLE_COMMAND_DEVINFO;
- mdev_add->mq->length = 0;
- maple_add_packet(mdev_add->mq);
+ maple_add_packet(mdev_add, 0, MAPLE_COMMAND_DEVINFO,
+ 0, NULL);
+ /* mark that we are checking sub devices */
scanning = 1;
}
submask = submask >> 1;
@@ -505,6 +592,28 @@
}
}
+static void maple_port_rescan(void)
+{
+ int i;
+ struct maple_device *mdev;
+
+ fullscan = 1;
+ for (i = 0; i < MAPLE_PORTS; i++) {
+ if (checked[i] == false) {
+ fullscan = 0;
+ mdev = baseunits[i];
+ /*
+ * test lock in case scan has failed
+ * but device is still locked
+ */
+ if (mutex_is_locked(&mdev->mq->mutex))
+ mutex_unlock(&mdev->mq->mutex);
+ maple_add_packet(mdev, 0, MAPLE_COMMAND_DEVINFO,
+ 0, NULL);
+ }
+ }
+}
+
/* maple dma end bottom half - implemented via workqueue */
static void maple_dma_handler(struct work_struct *work)
{
@@ -512,7 +621,6 @@
struct maple_device *dev;
char *recvbuf;
enum maple_code code;
- int i;
if (!maple_dma_done())
return;
@@ -522,6 +630,10 @@
recvbuf = mq->recvbuf;
code = recvbuf[0];
dev = mq->dev;
+ kfree(mq->sendbuf);
+ mutex_unlock(&mq->mutex);
+ list_del_init(&mq->list);
+
switch (code) {
case MAPLE_RESPONSE_NONE:
maple_response_none(dev, mq);
@@ -558,26 +670,16 @@
break;
}
}
- INIT_LIST_HEAD(&maple_sentq);
+ /* if scanning is 1 then we have subdevices to check */
if (scanning == 1) {
maple_send();
scanning = 2;
} else
scanning = 0;
-
- if (!fullscan) {
- fullscan = 1;
- for (i = 0; i < MAPLE_PORTS; i++) {
- if (checked[i] == false) {
- fullscan = 0;
- dev = baseunits[i];
- dev->mq->command =
- MAPLE_COMMAND_DEVINFO;
- dev->mq->length = 0;
- maple_add_packet(dev->mq);
- }
- }
- }
+ /*check if we have actually tested all ports yet */
+ if (!fullscan)
+ maple_port_rescan();
+ /* mark that we have been through the first scan */
if (started == 0)
started = 1;
}
@@ -631,7 +733,7 @@
if (maple_dev->devinfo.function == 0xFFFFFFFF)
return 0;
else if (maple_dev->devinfo.function &
- be32_to_cpu(maple_drv->function))
+ cpu_to_be32(maple_drv->function))
return 1;
return 0;
}
@@ -713,6 +815,9 @@
if (!maple_queue_cache)
goto cleanup_bothirqs;
+ INIT_LIST_HEAD(&maple_waitq);
+ INIT_LIST_HEAD(&maple_sentq);
+
/* setup maple ports */
for (i = 0; i < MAPLE_PORTS; i++) {
checked[i] = false;
@@ -723,9 +828,7 @@
maple_free_dev(mdev[i]);
goto cleanup_cache;
}
- mdev[i]->mq->command = MAPLE_COMMAND_DEVINFO;
- mdev[i]->mq->length = 0;
- maple_add_packet(mdev[i]->mq);
+ maple_add_packet(mdev[i], 0, MAPLE_COMMAND_DEVINFO, 0, NULL);
subdevice_map[i] = 0;
}