[PATCH v2 21/22] gpu: host1x: Refactor channel allocation code
Dmitry Osipenko
digetx at gmail.com
Tue Jun 13 23:16:00 UTC 2017
From: Mikko Perttunen <mperttunen at nvidia.com>
This is largely a rewrite of the Host1x channel allocation code, bringing
several changes:
- The previous code could deadlock due to an interaction
between the 'reflock' mutex and CDMA timeout handling.
This gets rid of the mutex.
- Support for more than 32 channels, required for Tegra186
- General refactoring, including better encapsulation
of channel ownership handling into channel.c
Signed-off-by: Mikko Perttunen <mperttunen at nvidia.com>
Reviewed-by: Dmitry Osipenko <digetx at gmail.com>
Tested-by: Dmitry Osipenko <digetx at gmail.com>
---
drivers/gpu/drm/tegra/gr2d.c | 4 +-
drivers/gpu/drm/tegra/gr3d.c | 4 +-
drivers/gpu/drm/tegra/vic.c | 4 +-
drivers/gpu/host1x/channel.c | 147 +++++++++++++++++++++++--------------
drivers/gpu/host1x/channel.h | 21 ++++--
drivers/gpu/host1x/debug.c | 47 +++++-------
drivers/gpu/host1x/dev.c | 7 +-
drivers/gpu/host1x/dev.h | 6 +-
drivers/gpu/host1x/hw/channel_hw.c | 4 -
include/linux/host1x.h | 1 -
10 files changed, 135 insertions(+), 110 deletions(-)
diff --git a/drivers/gpu/drm/tegra/gr2d.c b/drivers/gpu/drm/tegra/gr2d.c
index fbe0b8b25b42..6ea070da7718 100644
--- a/drivers/gpu/drm/tegra/gr2d.c
+++ b/drivers/gpu/drm/tegra/gr2d.c
@@ -38,7 +38,7 @@ static int gr2d_init(struct host1x_client *client)
client->syncpts[0] = host1x_syncpt_request(client->dev, flags);
if (!client->syncpts[0]) {
- host1x_channel_free(gr2d->channel);
+ host1x_channel_put(gr2d->channel);
return -ENOMEM;
}
@@ -57,7 +57,7 @@ static int gr2d_exit(struct host1x_client *client)
return err;
host1x_syncpt_free(client->syncpts[0]);
- host1x_channel_free(gr2d->channel);
+ host1x_channel_put(gr2d->channel);
return 0;
}
diff --git a/drivers/gpu/drm/tegra/gr3d.c b/drivers/gpu/drm/tegra/gr3d.c
index 13f0d1b7cd98..cee2ab645cde 100644
--- a/drivers/gpu/drm/tegra/gr3d.c
+++ b/drivers/gpu/drm/tegra/gr3d.c
@@ -48,7 +48,7 @@ static int gr3d_init(struct host1x_client *client)
client->syncpts[0] = host1x_syncpt_request(client->dev, flags);
if (!client->syncpts[0]) {
- host1x_channel_free(gr3d->channel);
+ host1x_channel_put(gr3d->channel);
return -ENOMEM;
}
@@ -67,7 +67,7 @@ static int gr3d_exit(struct host1x_client *client)
return err;
host1x_syncpt_free(client->syncpts[0]);
- host1x_channel_free(gr3d->channel);
+ host1x_channel_put(gr3d->channel);
return 0;
}
diff --git a/drivers/gpu/drm/tegra/vic.c b/drivers/gpu/drm/tegra/vic.c
index cd804e404a11..47cb1aaa58b1 100644
--- a/drivers/gpu/drm/tegra/vic.c
+++ b/drivers/gpu/drm/tegra/vic.c
@@ -182,7 +182,7 @@ static int vic_init(struct host1x_client *client)
free_syncpt:
host1x_syncpt_free(client->syncpts[0]);
free_channel:
- host1x_channel_free(vic->channel);
+ host1x_channel_put(vic->channel);
detach_device:
if (tegra->domain)
iommu_detach_device(tegra->domain, vic->dev);
@@ -203,7 +203,7 @@ static int vic_exit(struct host1x_client *client)
return err;
host1x_syncpt_free(client->syncpts[0]);
- host1x_channel_free(vic->channel);
+ host1x_channel_put(vic->channel);
if (vic->domain) {
iommu_detach_device(vic->domain, vic->dev);
diff --git a/drivers/gpu/host1x/channel.c b/drivers/gpu/host1x/channel.c
index 8f437d924c10..db9b91d1384c 100644
--- a/drivers/gpu/host1x/channel.c
+++ b/drivers/gpu/host1x/channel.c
@@ -24,19 +24,33 @@
#include "job.h"
/* Constructor for the host1x device list */
-int host1x_channel_list_init(struct host1x *host)
+int host1x_channel_list_init(struct host1x_channel_list *chlist,
+ unsigned int num_channels)
{
- INIT_LIST_HEAD(&host->chlist.list);
- mutex_init(&host->chlist_mutex);
-
- if (host->info->nb_channels > BITS_PER_LONG) {
- WARN(1, "host1x hardware has more channels than supported by the driver\n");
- return -ENOSYS;
+ chlist->channels = kcalloc(num_channels, sizeof(struct host1x_channel),
+ GFP_KERNEL);
+ if (!chlist->channels)
+ return -ENOMEM;
+
+ chlist->allocated_channels =
+ kcalloc(BITS_TO_LONGS(num_channels), sizeof(unsigned long),
+ GFP_KERNEL);
+ if (!chlist->allocated_channels) {
+ kfree(chlist->channels);
+ return -ENOMEM;
}
+ bitmap_zero(chlist->allocated_channels, num_channels);
+
return 0;
}
+void host1x_channel_list_free(struct host1x_channel_list *chlist)
+{
+ kfree(chlist->allocated_channels);
+ kfree(chlist->channels);
+}
+
int host1x_job_submit(struct host1x_job *job)
{
struct host1x *host = dev_get_drvdata(job->channel->dev->parent);
@@ -47,86 +61,107 @@ EXPORT_SYMBOL(host1x_job_submit);
struct host1x_channel *host1x_channel_get(struct host1x_channel *channel)
{
- int err = 0;
+ kref_get(&channel->refcount);
- mutex_lock(&channel->reflock);
+ return channel;
+}
+EXPORT_SYMBOL(host1x_channel_get);
- if (channel->refcount == 0)
- err = host1x_cdma_init(&channel->cdma);
+/**
+ * host1x_channel_get_index() - Attempt to get channel reference by index
+ * @host: Host1x device object
+ * @index: Index of channel
+ *
+ * If channel number @index is currently allocated, increase its refcount
+ * and return a pointer to it. Otherwise, return NULL.
+ */
+struct host1x_channel *host1x_channel_get_index(struct host1x *host,
+ unsigned int index)
+{
+ struct host1x_channel *ch = &host->channel_list.channels[index];
- if (!err)
- channel->refcount++;
+ if (!kref_get_unless_zero(&ch->refcount))
+ return NULL;
- mutex_unlock(&channel->reflock);
+ return ch;
+}
+
+static void release_channel(struct kref *kref)
+{
+ struct host1x_channel *channel =
+ container_of(kref, struct host1x_channel, refcount);
+ struct host1x *host = dev_get_drvdata(channel->dev->parent);
+ struct host1x_channel_list *chlist = &host->channel_list;
+
+ host1x_hw_cdma_stop(host, &channel->cdma);
+ host1x_cdma_deinit(&channel->cdma);
- return err ? NULL : channel;
+ clear_bit(channel->id, chlist->allocated_channels);
}
-EXPORT_SYMBOL(host1x_channel_get);
void host1x_channel_put(struct host1x_channel *channel)
{
- mutex_lock(&channel->reflock);
+ kref_put(&channel->refcount, release_channel);
+}
+EXPORT_SYMBOL(host1x_channel_put);
- if (channel->refcount == 1) {
- struct host1x *host = dev_get_drvdata(channel->dev->parent);
+static struct host1x_channel *acquire_unused_channel(struct host1x *host)
+{
+ struct host1x_channel_list *chlist = &host->channel_list;
+ unsigned int max_channels = host->info->nb_channels;
+ unsigned int index;
- host1x_hw_cdma_stop(host, &channel->cdma);
- host1x_cdma_deinit(&channel->cdma);
+ index = find_first_zero_bit(chlist->allocated_channels, max_channels);
+ if (index >= max_channels) {
+ dev_err(host->dev, "failed to find free channel\n");
+ return NULL;
}
- channel->refcount--;
+ chlist->channels[index].id = index;
- mutex_unlock(&channel->reflock);
+ set_bit(index, chlist->allocated_channels);
+
+ return &chlist->channels[index];
}
-EXPORT_SYMBOL(host1x_channel_put);
+/**
+ * host1x_channel_request() - Allocate a channel
+ * @device: Host1x unit this channel will be used to send commands to
+ *
+ * Allocates a new host1x channel for @device. If there are no free channels,
+ * this will sleep until one becomes available. May return NULL if CDMA
+ * initialization fails.
+ */
struct host1x_channel *host1x_channel_request(struct device *dev)
{
struct host1x *host = dev_get_drvdata(dev->parent);
- unsigned int max_channels = host->info->nb_channels;
- struct host1x_channel *channel = NULL;
- unsigned long index;
+ struct host1x_channel_list *chlist = &host->channel_list;
+ struct host1x_channel *channel;
int err;
- mutex_lock(&host->chlist_mutex);
+ channel = acquire_unused_channel(host);
+ if (!channel)
+ return NULL;
- index = find_first_zero_bit(&host->allocated_channels, max_channels);
- if (index >= max_channels)
- goto fail;
+ kref_init(&channel->refcount);
+ mutex_init(&channel->submitlock);
+ channel->dev = dev;
- channel = kzalloc(sizeof(*channel), GFP_KERNEL);
- if (!channel)
+ err = host1x_hw_channel_init(host, channel, channel->id);
+ if (err < 0)
goto fail;
- err = host1x_hw_channel_init(host, channel, index);
+ err = host1x_cdma_init(&channel->cdma);
if (err < 0)
goto fail;
- /* Link device to host1x_channel */
- channel->dev = dev;
-
- /* Add to channel list */
- list_add_tail(&channel->list, &host->chlist.list);
-
- host->allocated_channels |= BIT(index);
-
- mutex_unlock(&host->chlist_mutex);
return channel;
fail:
- dev_err(dev, "failed to init channel\n");
- kfree(channel);
- mutex_unlock(&host->chlist_mutex);
- return NULL;
-}
-EXPORT_SYMBOL(host1x_channel_request);
+ clear_bit(channel->id, chlist->allocated_channels);
-void host1x_channel_free(struct host1x_channel *channel)
-{
- struct host1x *host = dev_get_drvdata(channel->dev->parent);
+ dev_err(dev, "failed to initialize channel\n");
- host->allocated_channels &= ~BIT(channel->id);
- list_del(&channel->list);
- kfree(channel);
+ return NULL;
}
-EXPORT_SYMBOL(host1x_channel_free);
+EXPORT_SYMBOL(host1x_channel_request);
diff --git a/drivers/gpu/host1x/channel.h b/drivers/gpu/host1x/channel.h
index df767cf90d51..7068e42d42df 100644
--- a/drivers/gpu/host1x/channel.h
+++ b/drivers/gpu/host1x/channel.h
@@ -20,17 +20,21 @@
#define __HOST1X_CHANNEL_H
#include <linux/io.h>
+#include <linux/kref.h>
#include "cdma.h"
struct host1x;
+struct host1x_channel;
-struct host1x_channel {
- struct list_head list;
+struct host1x_channel_list {
+ struct host1x_channel *channels;
+ unsigned long *allocated_channels;
+};
- unsigned int refcount;
+struct host1x_channel {
+ struct kref refcount;
unsigned int id;
- struct mutex reflock;
struct mutex submitlock;
void __iomem *regs;
struct device *dev;
@@ -38,9 +42,10 @@ struct host1x_channel {
};
/* channel list operations */
-int host1x_channel_list_init(struct host1x *host);
-
-#define host1x_for_each_channel(host, channel) \
- list_for_each_entry(channel, &host->chlist.list, list)
+int host1x_channel_list_init(struct host1x_channel_list *chlist,
+ unsigned int num_channels);
+void host1x_channel_list_free(struct host1x_channel_list *chlist);
+struct host1x_channel *host1x_channel_get_index(struct host1x *host,
+ unsigned int index);
#endif
diff --git a/drivers/gpu/host1x/debug.c b/drivers/gpu/host1x/debug.c
index d9330fcc62ad..2aae0e63214c 100644
--- a/drivers/gpu/host1x/debug.c
+++ b/drivers/gpu/host1x/debug.c
@@ -43,24 +43,19 @@ void host1x_debug_output(struct output *o, const char *fmt, ...)
o->fn(o->ctx, o->buf, len);
}
-static int show_channels(struct host1x_channel *ch, void *data, bool show_fifo)
+static int show_channel(struct host1x_channel *ch, void *data, bool show_fifo)
{
struct host1x *m = dev_get_drvdata(ch->dev->parent);
struct output *o = data;
- mutex_lock(&ch->reflock);
+ mutex_lock(&ch->cdma.lock);
- if (ch->refcount) {
- mutex_lock(&ch->cdma.lock);
+ if (show_fifo)
+ host1x_hw_show_channel_fifo(m, ch, o);
- if (show_fifo)
- host1x_hw_show_channel_fifo(m, ch, o);
+ host1x_hw_show_channel_cdma(m, ch, o);
- host1x_hw_show_channel_cdma(m, ch, o);
- mutex_unlock(&ch->cdma.lock);
- }
-
- mutex_unlock(&ch->reflock);
+ mutex_unlock(&ch->cdma.lock);
return 0;
}
@@ -94,28 +89,22 @@ static void show_syncpts(struct host1x *m, struct output *o)
host1x_debug_output(o, "\n");
}
-static void show_all(struct host1x *m, struct output *o)
+static void show_all(struct host1x *m, struct output *o, bool show_fifo)
{
- struct host1x_channel *ch;
+ int i;
host1x_hw_show_mlocks(m, o);
show_syncpts(m, o);
host1x_debug_output(o, "---- channels ----\n");
- host1x_for_each_channel(m, ch)
- show_channels(ch, o, true);
-}
-
-static void show_all_no_fifo(struct host1x *host1x, struct output *o)
-{
- struct host1x_channel *ch;
-
- host1x_hw_show_mlocks(host1x, o);
- show_syncpts(host1x, o);
- host1x_debug_output(o, "---- channels ----\n");
+ for (i = 0; i < m->info->nb_channels; ++i) {
+ struct host1x_channel *ch = host1x_channel_get_index(m, i);
- host1x_for_each_channel(host1x, ch)
- show_channels(ch, o, false);
+ if (ch) {
+ show_channel(ch, o, show_fifo);
+ host1x_channel_put(ch);
+ }
+ }
}
static int host1x_debug_show_all(struct seq_file *s, void *unused)
@@ -125,7 +114,7 @@ static int host1x_debug_show_all(struct seq_file *s, void *unused)
.ctx = s
};
- show_all(s->private, &o);
+ show_all(s->private, &o, true);
return 0;
}
@@ -137,7 +126,7 @@ static int host1x_debug_show(struct seq_file *s, void *unused)
.ctx = s
};
- show_all_no_fifo(s->private, &o);
+ show_all(s->private, &o, false);
return 0;
}
@@ -216,7 +205,7 @@ void host1x_debug_dump(struct host1x *host1x)
.fn = write_to_printk
};
- show_all(host1x, &o);
+ show_all(host1x, &o, true);
}
void host1x_debug_dump_syncpts(struct host1x *host1x)
diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index 21da331ce092..18bc9dabb89d 100644
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -203,7 +203,8 @@ static int host1x_probe(struct platform_device *pdev)
host->iova_end = geometry->aperture_end;
}
- err = host1x_channel_list_init(host);
+ err = host1x_channel_list_init(&host->channel_list,
+ host->info->nb_channels);
if (err) {
dev_err(&pdev->dev, "failed to initialize channel list\n");
goto fail_detach_device;
@@ -212,7 +213,7 @@ static int host1x_probe(struct platform_device *pdev)
err = clk_prepare_enable(host->clk);
if (err < 0) {
dev_err(&pdev->dev, "failed to enable clock\n");
- goto fail_detach_device;
+ goto fail_free_channels;
}
err = reset_control_deassert(host->rst);
@@ -249,6 +250,8 @@ static int host1x_probe(struct platform_device *pdev)
reset_control_assert(host->rst);
fail_unprepare_disable:
clk_disable_unprepare(host->clk);
+fail_free_channels:
+ host1x_channel_list_free(&host->channel_list);
fail_detach_device:
if (host->domain) {
put_iova_domain(&host->iova);
diff --git a/drivers/gpu/host1x/dev.h b/drivers/gpu/host1x/dev.h
index c6997651b336..ec2eddec93cb 100644
--- a/drivers/gpu/host1x/dev.h
+++ b/drivers/gpu/host1x/dev.h
@@ -130,10 +130,8 @@ struct host1x {
struct host1x_syncpt *nop_sp;
struct mutex syncpt_mutex;
- struct mutex chlist_mutex;
- struct host1x_channel chlist;
- unsigned long allocated_channels;
- unsigned int num_allocated_channels;
+
+ struct host1x_channel_list channel_list;
struct dentry *debugfs;
diff --git a/drivers/gpu/host1x/hw/channel_hw.c b/drivers/gpu/host1x/hw/channel_hw.c
index 5e8df78b7acd..8447a56c41ca 100644
--- a/drivers/gpu/host1x/hw/channel_hw.c
+++ b/drivers/gpu/host1x/hw/channel_hw.c
@@ -181,10 +181,6 @@ static int channel_submit(struct host1x_job *job)
static int host1x_channel_init(struct host1x_channel *ch, struct host1x *dev,
unsigned int index)
{
- ch->id = index;
- mutex_init(&ch->reflock);
- mutex_init(&ch->submitlock);
-
ch->regs = dev->regs + index * HOST1X_CHANNEL_SIZE;
return 0;
}
diff --git a/include/linux/host1x.h b/include/linux/host1x.h
index 561d6bb6580d..5dd8df2f8810 100644
--- a/include/linux/host1x.h
+++ b/include/linux/host1x.h
@@ -156,7 +156,6 @@ struct host1x_channel;
struct host1x_job;
struct host1x_channel *host1x_channel_request(struct device *dev);
-void host1x_channel_free(struct host1x_channel *channel);
struct host1x_channel *host1x_channel_get(struct host1x_channel *channel);
void host1x_channel_put(struct host1x_channel *channel);
int host1x_job_submit(struct host1x_job *job);
--
2.13.0
More information about the dri-devel
mailing list