* [PATCH] pwm-backlight: add "max-brightness" property
From: Andrew Bresticker @ 2013-08-12 22:04 UTC (permalink / raw)
To: Richard Purdie, Jingoo Han
Cc: Olof Johansson, Rob Herring, Pawel Moll, Mark Rutland,
Stephen Warren, Ian Campbell, Rob Landley, Thierry Reding,
Jean-Christophe Plagniol-Villard, Tomi Valkeinen, devicetree,
linux-doc, linux-kernel, linux-pwm, linux-fbdev,
Andrew Bresticker
Specifying each individual brightness value via the "brightness-levels"
property can be a pain if we want to use a large continuous range of
brightness values. Add the property "max-brightness", which can be
given in place of "brightness-levels", that specifies that all values
between 0 and the given value can be used.
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
---
.../bindings/video/backlight/pwm-backlight.txt | 22 +++++++++---
drivers/video/backlight/pwm_bl.c | 39 +++++++++++++---------
2 files changed, 42 insertions(+), 19 deletions(-)
diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
index 1e4fc72..856dfc9 100644
--- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
+++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
@@ -3,15 +3,21 @@ pwm-backlight bindings
Required properties:
- compatible: "pwm-backlight"
- pwms: OF device-tree PWM specification (see PWM binding[0])
+ - one of "brightness-levels" or "max-brightness", described below
+ - default-brightness-level: the default brightness level (index into the array
+ defined by the "brightness-levels" property or a value between 0 and
+ "max-brightness")
+
+Optional properties:
- brightness-levels: Array of distinct brightness levels. Typically these
are in the range from 0 to 255, but any range starting at 0 will do.
The actual brightness level (PWM duty cycle) will be interpolated
from these values. 0 means a 0% duty cycle (darkest/off), while the
last value in the array represents a 100% duty cycle (brightest).
- - default-brightness-level: the default brightness level (index into the
- array defined by the "brightness-levels" property)
-
-Optional properties:
+ - max-brightness: Instead of specifying a complete set of brightness
+ levels, a single maximum brightness value may be given. This indicates
+ that all integers between 0 and max-brightness are valid brightness
+ values.
- pwm-names: a list of names for the PWM devices specified in the
"pwms" property (see PWM binding[0])
@@ -26,3 +32,11 @@ Example:
brightness-levels = <0 4 8 16 32 64 128 255>;
default-brightness-level = <6>;
};
+or:
+ backlight {
+ compatible = "pwm-backlight";
+ pwms = <&pwm 0 1000000 0>;
+
+ max-brightness = <1024>;
+ default-brightness-level = <700>;
+ };
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 1fea627..92973b1 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -98,7 +98,6 @@ static int pwm_backlight_parse_dt(struct device *dev,
struct platform_pwm_backlight_data *data)
{
struct device_node *node = dev->of_node;
- struct property *prop;
int length;
u32 value;
int ret;
@@ -108,34 +107,44 @@ static int pwm_backlight_parse_dt(struct device *dev,
memset(data, 0, sizeof(*data));
- /* determine the number of brightness levels */
- prop = of_find_property(node, "brightness-levels", &length);
- if (!prop)
- return -EINVAL;
+ if (of_find_property(node, "brightness-levels", &length)) {
+ data->max_brightness = length / sizeof(u32);
- data->max_brightness = length / sizeof(u32);
+ /* read brightness levels from DT property */
+ if (data->max_brightness > 0) {
+ size_t size = sizeof(*data->levels) *
+ data->max_brightness;
- /* read brightness levels from DT property */
- if (data->max_brightness > 0) {
- size_t size = sizeof(*data->levels) * data->max_brightness;
-
- data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
- if (!data->levels)
- return -ENOMEM;
+ data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
+ if (!data->levels)
+ return -ENOMEM;
- ret = of_property_read_u32_array(node, "brightness-levels",
+ ret = of_property_read_u32_array(node,
+ "brightness-levels",
data->levels,
data->max_brightness);
+ if (ret < 0)
+ return ret;
+
+ data->max_brightness--;
+ }
+ } else {
+ ret = of_property_read_u32(node, "max-brightness",
+ &value);
if (ret < 0)
return ret;
+ /* brightness values are 0 to max-brightness */
+ data->max_brightness = value;
+ }
+
+ if (data->max_brightness > 0) {
ret = of_property_read_u32(node, "default-brightness-level",
&value);
if (ret < 0)
return ret;
data->dft_brightness = value;
- data->max_brightness--;
}
/*
--
1.8.3
^ permalink raw reply related
* Re: [PATCH] pwm-backlight: add "max-brightness" property
From: Stephen Warren @ 2013-08-12 22:43 UTC (permalink / raw)
To: Andrew Bresticker
Cc: Richard Purdie, Jingoo Han, Olof Johansson, Rob Herring,
Pawel Moll, Mark Rutland, Ian Campbell, Rob Landley,
Thierry Reding, Jean-Christophe Plagniol-Villard, Tomi Valkeinen,
devicetree, linux-doc, linux-kernel, linux-pwm, linux-fbdev
In-Reply-To: <1376345057-29895-1-git-send-email-abrestic@chromium.org>
On 08/12/2013 04:04 PM, Andrew Bresticker wrote:
> Specifying each individual brightness value via the "brightness-levels"
> property can be a pain if we want to use a large continuous range of
> brightness values. Add the property "max-brightness", which can be
> given in place of "brightness-levels", that specifies that all values
> between 0 and the given value can be used.
What about the non-linear nature of PWM duty cycle <-> (perceived)
brightness level? That's why the values are typically enumerated. I
guess if you use this new property, you'd use a value of say 16;
exposing levels 0..255 to a user is probably more than they want?
^ permalink raw reply
* Re: [PATCH] pwm-backlight: add "max-brightness" property
From: Thierry Reding @ 2013-08-13 7:34 UTC (permalink / raw)
To: Andrew Bresticker
Cc: Richard Purdie, Jingoo Han, Olof Johansson, Rob Herring,
Pawel Moll, Mark Rutland, Stephen Warren, Ian Campbell,
Rob Landley, Jean-Christophe Plagniol-Villard, Tomi Valkeinen,
devicetree, linux-doc, linux-kernel, linux-pwm, linux-fbdev
In-Reply-To: <1376345057-29895-1-git-send-email-abrestic@chromium.org>
[-- Attachment #1: Type: text/plain, Size: 829 bytes --]
On Mon, Aug 12, 2013 at 03:04:17PM -0700, Andrew Bresticker wrote:
> Specifying each individual brightness value via the "brightness-levels"
> property can be a pain if we want to use a large continuous range of
> brightness values. Add the property "max-brightness", which can be
> given in place of "brightness-levels", that specifies that all values
> between 0 and the given value can be used.
This was actually part of my first attempt at a DT binding for this
driver as well. Some discussion ensued and we ended up changing the
binding to what it is now. And I think there was even an attempt already
at adding the same thing you propose (albeit under a different name). So
instead of repeating myself I'll just point you at the earlier thread:
https://groups.google.com/forum/#!topic/linux.kernel/UkXktWt6zI0
Thierry
[-- Attachment #2: Type: application/pgp-signature, Size: 836 bytes --]
^ permalink raw reply
* Re: [RFC 00/22] OMAPDSS: DT support
From: Tony Lindgren @ 2013-08-13 7:54 UTC (permalink / raw)
To: Tomi Valkeinen
Cc: linux-omap, linux-fbdev, devicetree, Archit Taneja,
Laurent Pinchart, Nishanth Menon, Felipe Balbi, Santosh Shilimkar
In-Reply-To: <1376037547-10859-1-git-send-email-tomi.valkeinen@ti.com>
* Tomi Valkeinen <tomi.valkeinen@ti.com> [130809 01:46]:
>
> So as is evident, I have things in my mind that should be improved. Maybe
> the most important question for short term future is:
>
> Can we add DSS DT bindings for OMAP4 as unstable bindings? It would give us
> some proper testing of the related code, and would also allow us to remove
> the related hacks (which don't even work quite right). However, I have no
> idea yet when the unstable DSS bindings would turn stable.
>
> If we shouldn't add the bindings as unstable, when should the bindings be
> added? Wait until CDF is in the mainline, and use that?
I don't think we should add any temporary bindings as it's going to be
a pain to support those in the long run. I suggest you initially just
stick to established bindings for the basic hardware IO address and
interrupts etc, then those should still be valid with the generic panel
bindings later on.
Regards,
Tony
^ permalink raw reply
* [RFC PATCH v6 0/2] Introduce buffer synchronization framework
From: Inki Dae @ 2013-08-13 9:19 UTC (permalink / raw)
To: dri-devel, linux-fbdev, linux-arm-kernel, linux-media,
linaro-kernel
Cc: maarten.lankhorst, sumit.semwal, kyungmin.park, myungjoo.ham,
Inki Dae
Hi all,
This patch set introduces a buffer synchronization framework based
on DMA BUF[1] and based on ww-mutexes[2] for lock mechanism, and
may be final RFC.
The purpose of this framework is to provide not only buffer access
control to CPU and CPU, and CPU and DMA, and DMA and DMA but also
easy-to-use interfaces for device drivers and user application.
In addtion, this patch set suggests a way for enhancing performance.
For generic user mode interface, we have used fcntl and select system
call[3]. As you know, user application sees a buffer object as a dma-buf
file descriptor. So fcntl() call with the file descriptor means to lock
some buffer region being managed by the dma-buf object. And select() call
means to wait for the completion of CPU or DMA access to the dma-buf
without locking. For more detail, you can refer to the dma-buf-sync.txt
in Documentation/
There are some cases we should use this buffer synchronization framework.
One of which is to primarily enhance GPU rendering performance on Tizen
platform in case of 3d app with compositing mode that 3d app draws
something in off-screen buffer, and Web app.
In case of 3d app with compositing mode which is not a full screen mode,
the app calls glFlush to submit 3d commands to GPU driver instead of
glFinish for more performance. The reason we call glFlush is that glFinish
blocks caller's task until the execution of the 2d commands is completed.
Thus, that makes GPU and CPU more idle. As result, 3d rendering performance
with glFinish is quite lower than glFlush. However, the use of glFlush has
one issue that the a buffer shared with GPU could be broken when CPU
accesses the buffer at once after glFlush because CPU cannot be aware of
the completion of GPU access to the buffer. Of course, the app can be aware
of that time using eglWaitGL but this function is valid only in case of the
same process.
In case of Tizen, there are some applications that one process draws
something in its own off-screen buffer (pixmap buffer) using CPU, and other
process gets a off-screen buffer (window buffer) from Xorg using
DRI2GetBuffers, and then composites the pixmap buffer with the window buffer
using GPU, and finally page flip.
Web app based on HTML5 also has the same issue. Web browser and its web app
are different process. The web app draws something in its own pixmap buffer,
and then the web browser gets a window buffer from Xorg, and then composites
the pixmap buffer with the window buffer. And finally, page flip.
Thus, in such cases, a shared buffer could be broken as one process draws
something in pixmap buffer using CPU, when other process composites the
pixmap buffer with window buffer using GPU without any locking mechanism.
That is why we need user land locking interface, fcntl system call.
And last one is a deferred page flip issue. This issue is that a window
buffer rendered can be displayed on screen in about 32ms in worst case:
assume that the gpu rendering is completed within 16ms.
That can be incurred when compositing a pixmap buffer with a window buffer
using GPU and when vsync is just started. At this time, Xorg waits for
a vblank event to get a window buffer so 3d rendering will be delayed
up to about 16ms. As a result, the window buffer would be displayed in
about two vsyncs (about 32ms) and in turn, that would show slow
responsiveness.
For this, we could enhance the responsiveness with locking
mechanism: skipping one vblank wait. I guess in the similar reason,
Android, Chrome OS, and other platforms are using their own locking
mechanisms; Android sync driver, KDS, and DMA fence.
The below shows the deferred page flip issue in worst case,
|------------ <- vsync signal
|<------ DRI2GetBuffers
|
|
|
|------------ <- vsync signal
|<------ Request gpu rendering
time |
|
|<------ Request page flip (deferred)
|------------ <- vsync signal
|<------ Displayed on screen
|
|
|
|------------ <- vsync signal
Thanks,
Inki Dae
References:
[1] http://lwn.net/Articles/470339/
[2] https://patchwork.kernel.org/patch/2625361/
[3] http://linux.die.net/man/2/fcntl
Inki Dae (2):
[RFC PATCH v6] dmabuf-sync: Add a buffer synchronization framework
[RFC PATCH v2] dma-buf: Add user interfaces for dmabuf sync support.
Documentation/dma-buf-sync.txt | 285 +++++++++++++++++
drivers/base/Kconfig | 7 +
drivers/base/Makefile | 1 +
drivers/base/dma-buf.c | 85 +++++
drivers/base/dmabuf-sync.c | 678 ++++++++++++++++++++++++++++++++++++++++
include/linux/dma-buf.h | 16 +
include/linux/dmabuf-sync.h | 191 +++++++++++
7 files changed, 1263 insertions(+), 0 deletions(-)
create mode 100644 Documentation/dma-buf-sync.txt
create mode 100644 drivers/base/dmabuf-sync.c
create mode 100644 include/linux/dmabuf-sync.h
--
1.7.5.4
^ permalink raw reply
* [PATCH 1/2] [RFC PATCH v6] dmabuf-sync: Add a buffer synchronization framework
From: Inki Dae @ 2013-08-13 9:19 UTC (permalink / raw)
To: dri-devel, linux-fbdev, linux-arm-kernel, linux-media,
linaro-kernel
Cc: maarten.lankhorst, sumit.semwal, kyungmin.park, myungjoo.ham,
Inki Dae
In-Reply-To: <1376385576-9039-1-git-send-email-inki.dae@samsung.com>
This patch adds a buffer synchronization framework based on DMA BUF[1]
and and based on ww-mutexes[2] for lock mechanism.
The purpose of this framework is to provide not only buffer access control
to CPU and DMA but also easy-to-use interfaces for device drivers and
user application. This framework can be used for all dma devices using
system memory as dma buffer, especially for most ARM based SoCs.
Changelog v6:
- Fix sync lock to multiple reads.
- Add select system call support.
. Wake up poll_wait when a dmabuf is unlocked.
- Remove unnecessary the use of mutex lock.
- Add private backend ops callbacks.
. This ops has one callback for device drivers to clean up their
sync object resource when the sync object is freed. For this,
device drivers should implement the free callback properly.
- Update document file.
Changelog v5:
- Rmove a dependence on reservation_object: the reservation_object is used
to hook up to ttm and dma-buf for easy sharing of reservations across
devices. However, the dmabuf sync can be used for all dma devices; v4l2
and drm based drivers, so doesn't need the reservation_object anymore.
With regared to this, it adds 'void *sync' to dma_buf structure.
- All patches are rebased on mainline, Linux v3.10.
Changelog v4:
- Add user side interface for buffer synchronization mechanism and update
descriptions related to the user side interface.
Changelog v3:
- remove cache operation relevant codes and update document file.
Changelog v2:
- use atomic_add_unless to avoid potential bug.
- add a macro for checking valid access type.
- code clean.
The mechanism of this framework has the following steps,
1. Register dmabufs to a sync object - A task gets a new sync object and
can add one or more dmabufs that the task wants to access.
This registering should be performed when a device context or an event
context such as a page flip event is created or before CPU accesses a shared
buffer.
dma_buf_sync_get(a sync object, a dmabuf);
2. Lock a sync object - A task tries to lock all dmabufs added in its own
sync object. Basically, the lock mechanism uses ww-mutex[1] to avoid dead
lock issue and for race condition between CPU and CPU, CPU and DMA, and DMA
and DMA. Taking a lock means that others cannot access all locked dmabufs
until the task that locked the corresponding dmabufs, unlocks all the locked
dmabufs.
This locking should be performed before DMA or CPU accesses these dmabufs.
dma_buf_sync_lock(a sync object);
3. Unlock a sync object - The task unlocks all dmabufs added in its own sync
object. The unlock means that the DMA or CPU accesses to the dmabufs have
been completed so that others may access them.
This unlocking should be performed after DMA or CPU has completed accesses
to the dmabufs.
dma_buf_sync_unlock(a sync object);
4. Unregister one or all dmabufs from a sync object - A task unregisters
the given dmabufs from the sync object. This means that the task dosen't
want to lock the dmabufs.
The unregistering should be performed after DMA or CPU has completed
accesses to the dmabufs or when dma_buf_sync_lock() is failed.
dma_buf_sync_put(a sync object, a dmabuf);
dma_buf_sync_put_all(a sync object);
The described steps may be summarized as:
get -> lock -> CPU or DMA access to a buffer/s -> unlock -> put
This framework includes the following two features.
1. read (shared) and write (exclusive) locks - A task is required to declare
the access type when the task tries to register a dmabuf;
READ, WRITE, READ DMA, or WRITE DMA.
The below is example codes,
struct dmabuf_sync *sync;
sync = dmabuf_sync_init(...);
...
dmabuf_sync_get(sync, dmabuf, DMA_BUF_ACCESS_R);
...
And the below can be used as access types:
DMA_BUF_ACCESS_R - CPU will access a buffer for read.
DMA_BUF_ACCESS_W - CPU will access a buffer for read or write.
DMA_BUF_ACCESS_DMA_R - DMA will access a buffer for read
DMA_BUF_ACCESS_DMA_W - DMA will access a buffer for read or
write.
2. Mandatory resource releasing - a task cannot hold a lock indefinitely.
A task may never try to unlock a buffer after taking a lock to the buffer.
In this case, a timer handler to the corresponding sync object is called
in five (default) seconds and then the timed-out buffer is unlocked by work
queue handler to avoid lockups and to enforce resources of the buffer.
The below is how to use interfaces for device driver:
1. Allocate and Initialize a sync object:
static void xxx_dmabuf_sync_free(void *priv)
{
struct xxx_context *ctx = priv;
if (!ctx)
return;
ctx->sync = NULL;
}
...
static struct dmabuf_sync_priv_ops driver_specific_ops = {
.free = xxx_dmabuf_sync_free,
};
...
struct dmabuf_sync *sync;
sync = dmabuf_sync_init("test sync", &driver_specific_ops, ctx);
...
2. Add a dmabuf to the sync object when setting up dma buffer relevant
registers:
dmabuf_sync_get(sync, dmabuf, DMA_BUF_ACCESS_READ);
...
3. Lock all dmabufs of the sync object before DMA or CPU accesses
the dmabufs:
dmabuf_sync_lock(sync);
...
4. Now CPU or DMA can access all dmabufs locked in step 3.
5. Unlock all dmabufs added in a sync object after DMA or CPU access
to these dmabufs is completed:
dmabuf_sync_unlock(sync);
And call the following functions to release all resources,
dmabuf_sync_put_all(sync);
dmabuf_sync_fini(sync);
You can refer to actual example codes:
"drm/exynos: add dmabuf sync support for g2d driver" and
"drm/exynos: add dmabuf sync support for kms framework" from
https://git.kernel.org/cgit/linux/kernel/git/daeinki/
drm-exynos.git/log/?h=dmabuf-sync
And this framework includes fcntl system call[3] as interfaces exported
to user. As you know, user sees a buffer object as a dma-buf file descriptor.
So fcntl() call with the file descriptor means to lock some buffer region being
managed by the dma-buf object.
The below is how to use interfaces for user application:
fcntl system call:
struct flock filelock;
1. Lock a dma buf:
filelock.l_type = F_WRLCK or F_RDLCK;
/* lock entire region to the dma buf. */
filelock.lwhence = SEEK_CUR;
filelock.l_start = 0;
filelock.l_len = 0;
fcntl(dmabuf fd, F_SETLKW or F_SETLK, &filelock);
...
CPU access to the dma buf
2. Unlock a dma buf:
filelock.l_type = F_UNLCK;
fcntl(dmabuf fd, F_SETLKW or F_SETLK, &filelock);
close(dmabuf fd) call would also unlock the dma buf. And for more
detail, please refer to [3]
select system call:
fd_set wdfs or rdfs;
FD_ZERO(&wdfs or &rdfs);
FD_SET(fd, &wdfs or &rdfs);
select(fd + 1, &rdfs, NULL, NULL, NULL);
or
select(fd + 1, NULL, &wdfs, NULL, NULL);
Every time select system call is called, a caller will wait for
the completion of DMA or CPU access to a shared buffer if there
is someone accessing the shared buffer; locked the shared buffer.
However, if no anyone then select system call will be returned
at once.
References:
[1] http://lwn.net/Articles/470339/
[2] https://patchwork.kernel.org/patch/2625361/
[3] http://linux.die.net/man/2/fcntl
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
Documentation/dma-buf-sync.txt | 285 +++++++++++++++++
drivers/base/Kconfig | 7 +
drivers/base/Makefile | 1 +
drivers/base/dma-buf.c | 4 +
drivers/base/dmabuf-sync.c | 678 ++++++++++++++++++++++++++++++++++++++++
include/linux/dma-buf.h | 16 +
include/linux/dmabuf-sync.h | 190 +++++++++++
7 files changed, 1181 insertions(+), 0 deletions(-)
create mode 100644 Documentation/dma-buf-sync.txt
create mode 100644 drivers/base/dmabuf-sync.c
create mode 100644 include/linux/dmabuf-sync.h
diff --git a/Documentation/dma-buf-sync.txt b/Documentation/dma-buf-sync.txt
new file mode 100644
index 0000000..8023d06
--- /dev/null
+++ b/Documentation/dma-buf-sync.txt
@@ -0,0 +1,285 @@
+ DMA Buffer Synchronization Framework
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+ Inki Dae
+ <inki dot dae at samsung dot com>
+ <daeinki at gmail dot com>
+
+This document is a guide for device-driver writers describing the DMA buffer
+synchronization API. This document also describes how to use the API to
+use buffer synchronization mechanism between DMA and DMA, CPU and DMA, and
+CPU and CPU.
+
+The DMA Buffer synchronization API provides buffer synchronization mechanism;
+i.e., buffer access control to CPU and DMA, and easy-to-use interfaces for
+device drivers and user application. And this API can be used for all dma
+devices using system memory as dma buffer, especially for most ARM based SoCs.
+
+
+Motivation
+----------
+
+Buffer synchronization issue between DMA and DMA:
+ Sharing a buffer, a device cannot be aware of when the other device
+ will access the shared buffer: a device may access a buffer containing
+ wrong data if the device accesses the shared buffer while another
+ device is still accessing the shared buffer.
+ Therefore, a user process should have waited for the completion of DMA
+ access by another device before a device tries to access the shared
+ buffer.
+
+Buffer synchronization issue between CPU and DMA:
+ A user process should consider that when having to send a buffer, filled
+ by CPU, to a device driver for the device driver to access the buffer as
+ a input buffer while CPU and DMA are sharing the buffer.
+ This means that the user process needs to understand how the device
+ driver is worked. Hence, the conventional mechanism not only makes
+ user application complicated but also incurs performance overhead.
+
+Buffer synchronization issue between CPU and CPU:
+ In case that two processes share one buffer; shared with DMA also,
+ they may need some mechanism to allow process B to access the shared
+ buffer after the completion of CPU access by process A.
+ Therefore, process B should have waited for the completion of CPU access
+ by process A using the mechanism before trying to access the shared
+ buffer.
+
+What is the best way to solve these buffer synchronization issues?
+ We may need a common object that a device driver and a user process
+ notify the common object of when they try to access a shared buffer.
+ That way we could decide when we have to allow or not to allow for CPU
+ or DMA to access the shared buffer through the common object.
+ If so, what could become the common object? Right, that's a dma-buf[1].
+ Now we have already been using the dma-buf to share one buffer with
+ other drivers.
+
+
+Basic concept
+-------------
+
+The mechanism of this framework has the following steps,
+ 1. Register dmabufs to a sync object - A task gets a new sync object and
+ can add one or more dmabufs that the task wants to access.
+ This registering should be performed when a device context or an event
+ context such as a page flip event is created or before CPU accesses a shared
+ buffer.
+
+ dma_buf_sync_get(a sync object, a dmabuf);
+
+ 2. Lock a sync object - A task tries to lock all dmabufs added in its own
+ sync object. Basically, the lock mechanism uses ww-mutexes[2] to avoid dead
+ lock issue and for race condition between CPU and CPU, CPU and DMA, and DMA
+ and DMA. Taking a lock means that others cannot access all locked dmabufs
+ until the task that locked the corresponding dmabufs, unlocks all the locked
+ dmabufs.
+ This locking should be performed before DMA or CPU accesses these dmabufs.
+
+ dma_buf_sync_lock(a sync object);
+
+ 3. Unlock a sync object - The task unlocks all dmabufs added in its own sync
+ object. The unlock means that the DMA or CPU accesses to the dmabufs have
+ been completed so that others may access them.
+ This unlocking should be performed after DMA or CPU has completed accesses
+ to the dmabufs.
+
+ dma_buf_sync_unlock(a sync object);
+
+ 4. Unregister one or all dmabufs from a sync object - A task unregisters
+ the given dmabufs from the sync object. This means that the task dosen't
+ want to lock the dmabufs.
+ The unregistering should be performed after DMA or CPU has completed
+ accesses to the dmabufs or when dma_buf_sync_lock() is failed.
+
+ dma_buf_sync_put(a sync object, a dmabuf);
+ dma_buf_sync_put_all(a sync object);
+
+ The described steps may be summarized as:
+ get -> lock -> CPU or DMA access to a buffer/s -> unlock -> put
+
+This framework includes the following two features.
+ 1. read (shared) and write (exclusive) locks - A task is required to declare
+ the access type when the task tries to register a dmabuf;
+ READ, WRITE, READ DMA, or WRITE DMA.
+
+ The below is example codes,
+ struct dmabuf_sync *sync;
+
+ sync = dmabuf_sync_init(NULL, "test sync");
+
+ dmabuf_sync_get(sync, dmabuf, DMA_BUF_ACCESS_R);
+ ...
+
+ 2. Mandatory resource releasing - a task cannot hold a lock indefinitely.
+ A task may never try to unlock a buffer after taking a lock to the buffer.
+ In this case, a timer handler to the corresponding sync object is called
+ in five (default) seconds and then the timed-out buffer is unlocked by work
+ queue handler to avoid lockups and to enforce resources of the buffer.
+
+
+Access types
+------------
+
+DMA_BUF_ACCESS_R - CPU will access a buffer for read.
+DMA_BUF_ACCESS_W - CPU will access a buffer for read or write.
+DMA_BUF_ACCESS_DMA_R - DMA will access a buffer for read
+DMA_BUF_ACCESS_DMA_W - DMA will access a buffer for read or write.
+
+
+Generic user interfaces
+-----------------------
+
+And this framework includes fcntl system call[3] as interfaces exported
+to user. As you know, user sees a buffer object as a dma-buf file descriptor.
+So fcntl() call with the file descriptor means to lock some buffer region being
+managed by the dma-buf object.
+
+
+API set
+-------
+
+bool is_dmabuf_sync_supported(void)
+ - Check if dmabuf sync is supported or not.
+
+struct dmabuf_sync *dmabuf_sync_init(const char *name,
+ struct dmabuf_sync_priv_ops *ops,
+ void priv*)
+ - Allocate and initialize a new sync object. The caller can get a new
+ sync object for buffer synchronization. ops is used for device driver
+ to clean up its own sync object. For this, each device driver should
+ implement a free callback. priv is used for device driver to get its
+ device context when free callback is called.
+
+void dmabuf_sync_fini(struct dmabuf_sync *sync)
+ - Release all resources to the sync object.
+
+int dmabuf_sync_get(struct dmabuf_sync *sync, void *sync_buf,
+ unsigned int type)
+ - Get dmabuf sync object. Internally, this function allocates
+ a dmabuf_sync object and adds a given dmabuf to it, and also takes
+ a reference to the dmabuf. The caller can tie up multiple dmabufs
+ into one sync object by calling this function several times.
+
+void dmabuf_sync_put(struct dmabuf_sync *sync, struct dma_buf *dmabuf)
+ - Put dmabuf sync object to a given dmabuf. Internally, this function
+ removes a given dmabuf from a sync object and remove the sync object.
+ At this time, the dmabuf is putted.
+
+void dmabuf_sync_put_all(struct dmabuf_sync *sync)
+ - Put dmabuf sync object to dmabufs. Internally, this function removes
+ all dmabufs from a sync object and remove the sync object.
+ At this time, all dmabufs are putted.
+
+int dmabuf_sync_lock(struct dmabuf_sync *sync)
+ - Lock all dmabufs added in a sync object. The caller should call this
+ function prior to CPU or DMA access to the dmabufs so that others can
+ not access the dmabufs. Internally, this function avoids dead lock
+ issue with ww-mutexes.
+
+int dmabuf_sync_single_lock(struct dma_buf *dmabuf)
+ - Lock a dmabuf. The caller should call this
+ function prior to CPU or DMA access to the dmabuf so that others can
+ not access the dmabuf.
+
+int dmabuf_sync_unlock(struct dmabuf_sync *sync)
+ - Unlock all dmabufs added in a sync object. The caller should call
+ this function after CPU or DMA access to the dmabufs is completed so
+ that others can access the dmabufs.
+
+void dmabuf_sync_single_unlock(struct dma_buf *dmabuf)
+ - Unlock a dmabuf. The caller should call this function after CPU or
+ DMA access to the dmabuf is completed so that others can access
+ the dmabuf.
+
+
+Tutorial for device driver
+--------------------------
+
+1. Allocate and Initialize a sync object:
+ static void xxx_dmabuf_sync_free(void *priv)
+ {
+ struct xxx_context *ctx = priv;
+
+ if (!ctx)
+ return;
+
+ ctx->sync = NULL;
+ }
+ ...
+
+ static struct dmabuf_sync_priv_ops driver_specific_ops = {
+ .free = xxx_dmabuf_sync_free,
+ };
+ ...
+
+ struct dmabuf_sync *sync;
+
+ sync = dmabuf_sync_init("test sync", &driver_specific_ops, ctx);
+ ...
+
+2. Add a dmabuf to the sync object when setting up dma buffer relevant registers:
+ dmabuf_sync_get(sync, dmabuf, DMA_BUF_ACCESS_READ);
+ ...
+
+3. Lock all dmabufs of the sync object before DMA or CPU accesses the dmabufs:
+ dmabuf_sync_lock(sync);
+ ...
+
+4. Now CPU or DMA can access all dmabufs locked in step 3.
+
+5. Unlock all dmabufs added in a sync object after DMA or CPU access to these
+ dmabufs is completed:
+ dmabuf_sync_unlock(sync);
+
+ And call the following functions to release all resources,
+ dmabuf_sync_put_all(sync);
+ dmabuf_sync_fini(sync);
+
+
+Tutorial for user application
+-----------------------------
+fcntl system call:
+
+ struct flock filelock;
+
+1. Lock a dma buf:
+ filelock.l_type = F_WRLCK or F_RDLCK;
+
+ /* lock entire region to the dma buf. */
+ filelock.lwhence = SEEK_CUR;
+ filelock.l_start = 0;
+ filelock.l_len = 0;
+
+ fcntl(dmabuf fd, F_SETLKW or F_SETLK, &filelock);
+ ...
+ CPU access to the dma buf
+
+2. Unlock a dma buf:
+ filelock.l_type = F_UNLCK;
+
+ fcntl(dmabuf fd, F_SETLKW or F_SETLK, &filelock);
+
+ close(dmabuf fd) call would also unlock the dma buf. And for more
+ detail, please refer to [3]
+
+
+select system call:
+
+ fd_set wdfs or rdfs;
+
+ FD_ZERO(&wdfs or &rdfs);
+ FD_SET(fd, &wdfs or &rdfs);
+
+ select(fd + 1, &rdfs, NULL, NULL, NULL);
+ or
+ select(fd + 1, NULL, &wdfs, NULL, NULL);
+
+ Every time select system call is called, a caller will wait for
+ the completion of DMA or CPU access to a shared buffer if there is
+ someone accessing the shared buffer; locked the shared buffer.
+ However, if no anyone then select system call will be returned
+ at once.
+
+References:
+[1] http://lwn.net/Articles/470339/
+[2] https://patchwork.kernel.org/patch/2625361/
+[3] http://linux.die.net/man/2/fcntl
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 5daa259..35e1518 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -200,6 +200,13 @@ config DMA_SHARED_BUFFER
APIs extension; the file's descriptor can then be passed on to other
driver.
+config DMABUF_SYNC
+ bool "DMABUF Synchronization Framework"
+ depends on DMA_SHARED_BUFFER
+ help
+ This option enables dmabuf sync framework for buffer synchronization between
+ DMA and DMA, CPU and DMA, and CPU and CPU.
+
config CMA
bool "Contiguous Memory Allocator"
depends on HAVE_DMA_CONTIGUOUS && HAVE_MEMBLOCK
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 48029aa..e06a5d7 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -11,6 +11,7 @@ obj-y += power/
obj-$(CONFIG_HAS_DMA) += dma-mapping.o
obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf.o reservation.o
+obj-$(CONFIG_DMABUF_SYNC) += dmabuf-sync.o
obj-$(CONFIG_ISA) += isa.o
obj-$(CONFIG_FW_LOADER) += firmware_class.o
obj-$(CONFIG_NUMA) += node.o
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 6687ba7..4aca57a 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -29,6 +29,7 @@
#include <linux/export.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
+#include <linux/dmabuf-sync.h>
static inline int is_dma_buf_file(struct file *);
@@ -56,6 +57,8 @@ static int dma_buf_release(struct inode *inode, struct file *file)
list_del(&dmabuf->list_node);
mutex_unlock(&db_list.lock);
+ dmabuf_sync_reservation_fini(dmabuf);
+
kfree(dmabuf);
return 0;
}
@@ -134,6 +137,7 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
+ dmabuf_sync_reservation_init(dmabuf);
dmabuf->file = file;
mutex_init(&dmabuf->lock);
diff --git a/drivers/base/dmabuf-sync.c b/drivers/base/dmabuf-sync.c
new file mode 100644
index 0000000..fbe711c
--- /dev/null
+++ b/drivers/base/dmabuf-sync.c
@@ -0,0 +1,678 @@
+/*
+ * Copyright (C) 2013 Samsung Electronics Co.Ltd
+ * Authors:
+ * Inki Dae <inki.dae@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+
+#include <linux/dmabuf-sync.h>
+
+#define MAX_SYNC_TIMEOUT 5 /* Second. */
+
+int dmabuf_sync_enabled = 1;
+
+MODULE_PARM_DESC(enabled, "Check if dmabuf sync is supported or not");
+module_param_named(enabled, dmabuf_sync_enabled, int, 0444);
+
+DEFINE_WW_CLASS(dmabuf_sync_ww_class);
+EXPORT_SYMBOL(dmabuf_sync_ww_class);
+
+static void dmabuf_sync_timeout_worker(struct work_struct *work)
+{
+ struct dmabuf_sync *sync = container_of(work, struct dmabuf_sync, work);
+ struct dmabuf_sync_object *sobj;
+
+ mutex_lock(&sync->lock);
+
+ list_for_each_entry(sobj, &sync->syncs, head) {
+ BUG_ON(!sobj->robj);
+
+ mutex_lock(&sobj->robj->lock);
+
+ printk(KERN_WARNING "%s: timeout = 0x%x [type = %d:%d, " \
+ "refcnt = %d, locked = %d]\n",
+ sync->name, (u32)sobj->dmabuf,
+ sobj->robj->accessed_type,
+ sobj->access_type,
+ atomic_read(&sobj->robj->shared_cnt),
+ sobj->robj->locked);
+
+ /* unlock only valid sync object. */
+ if (!sobj->robj->locked) {
+ mutex_unlock(&sobj->robj->lock);
+ continue;
+ }
+
+ if (sobj->robj->polled) {
+ sobj->robj->poll_event = true;
+ sobj->robj->polled = false;
+ wake_up_interruptible(&sobj->robj->poll_wait);
+ }
+
+ if (atomic_add_unless(&sobj->robj->shared_cnt, -1, 1)) {
+ mutex_unlock(&sobj->robj->lock);
+ continue;
+ }
+
+ mutex_unlock(&sobj->robj->lock);
+
+ ww_mutex_unlock(&sobj->robj->sync_lock);
+
+ mutex_lock(&sobj->robj->lock);
+ sobj->robj->locked = false;
+
+ if (sobj->access_type & DMA_BUF_ACCESS_R)
+ printk(KERN_WARNING "%s: r-unlocked = 0x%x\n",
+ sync->name, (u32)sobj->dmabuf);
+ else
+ printk(KERN_WARNING "%s: w-unlocked = 0x%x\n",
+ sync->name, (u32)sobj->dmabuf);
+
+ mutex_unlock(&sobj->robj->lock);
+ }
+
+ sync->status = 0;
+ mutex_unlock(&sync->lock);
+
+ dmabuf_sync_put_all(sync);
+ dmabuf_sync_fini(sync);
+}
+
+static void dmabuf_sync_lock_timeout(unsigned long arg)
+{
+ struct dmabuf_sync *sync = (struct dmabuf_sync *)arg;
+
+ schedule_work(&sync->work);
+}
+
+static int dmabuf_sync_lock_objs(struct dmabuf_sync *sync,
+ struct ww_acquire_ctx *ctx)
+{
+ struct dmabuf_sync_object *contended_sobj = NULL;
+ struct dmabuf_sync_object *res_sobj = NULL;
+ struct dmabuf_sync_object *sobj = NULL;
+ int ret;
+
+ if (ctx)
+ ww_acquire_init(ctx, &dmabuf_sync_ww_class);
+
+retry:
+ list_for_each_entry(sobj, &sync->syncs, head) {
+ if (WARN_ON(!sobj->robj))
+ continue;
+
+ mutex_lock(&sobj->robj->lock);
+
+ /* Don't lock in case of read and read. */
+ if (sobj->robj->accessed_type & DMA_BUF_ACCESS_R &&
+ sobj->access_type & DMA_BUF_ACCESS_R) {
+ atomic_inc(&sobj->robj->shared_cnt);
+ mutex_unlock(&sobj->robj->lock);
+ continue;
+ }
+
+ if (sobj = res_sobj) {
+ res_sobj = NULL;
+ mutex_unlock(&sobj->robj->lock);
+ continue;
+ }
+
+ mutex_unlock(&sobj->robj->lock);
+
+ ret = ww_mutex_lock(&sobj->robj->sync_lock, ctx);
+ if (ret < 0) {
+ contended_sobj = sobj;
+
+ if (ret = -EDEADLK)
+ printk(KERN_WARNING"%s: deadlock = 0x%x\n",
+ sync->name, (u32)sobj->dmabuf);
+ goto err;
+ }
+
+ mutex_lock(&sobj->robj->lock);
+ sobj->robj->locked = true;
+
+ mutex_unlock(&sobj->robj->lock);
+ }
+
+ if (ctx)
+ ww_acquire_done(ctx);
+
+ init_timer(&sync->timer);
+
+ sync->timer.data = (unsigned long)sync;
+ sync->timer.function = dmabuf_sync_lock_timeout;
+ sync->timer.expires = jiffies + (HZ * MAX_SYNC_TIMEOUT);
+
+ add_timer(&sync->timer);
+
+ return 0;
+
+err:
+ list_for_each_entry_continue_reverse(sobj, &sync->syncs, head) {
+ mutex_lock(&sobj->robj->lock);
+
+ /* Don't need to unlock in case of read and read. */
+ if (atomic_add_unless(&sobj->robj->shared_cnt, -1, 1)) {
+ mutex_unlock(&sobj->robj->lock);
+ continue;
+ }
+
+ ww_mutex_unlock(&sobj->robj->sync_lock);
+ sobj->robj->locked = false;
+
+ mutex_unlock(&sobj->robj->lock);
+ }
+
+ if (res_sobj) {
+ mutex_lock(&res_sobj->robj->lock);
+
+ if (!atomic_add_unless(&res_sobj->robj->shared_cnt, -1, 1)) {
+ ww_mutex_unlock(&res_sobj->robj->sync_lock);
+ res_sobj->robj->locked = false;
+ }
+
+ mutex_unlock(&res_sobj->robj->lock);
+ }
+
+ if (ret = -EDEADLK) {
+ ww_mutex_lock_slow(&contended_sobj->robj->sync_lock, ctx);
+ res_sobj = contended_sobj;
+
+ goto retry;
+ }
+
+ if (ctx)
+ ww_acquire_fini(ctx);
+
+ return ret;
+}
+
+static void dmabuf_sync_unlock_objs(struct dmabuf_sync *sync,
+ struct ww_acquire_ctx *ctx)
+{
+ struct dmabuf_sync_object *sobj;
+
+ if (list_empty(&sync->syncs))
+ return;
+
+ mutex_lock(&sync->lock);
+
+ list_for_each_entry(sobj, &sync->syncs, head) {
+ mutex_lock(&sobj->robj->lock);
+
+ if (sobj->robj->polled) {
+ sobj->robj->poll_event = true;
+ sobj->robj->polled = false;
+ wake_up_interruptible(&sobj->robj->poll_wait);
+ }
+
+ if (atomic_add_unless(&sobj->robj->shared_cnt, -1, 1)) {
+ mutex_unlock(&sobj->robj->lock);
+ continue;
+ }
+
+ mutex_unlock(&sobj->robj->lock);
+
+ ww_mutex_unlock(&sobj->robj->sync_lock);
+
+ mutex_lock(&sobj->robj->lock);
+ sobj->robj->locked = false;
+ mutex_unlock(&sobj->robj->lock);
+ }
+
+ mutex_unlock(&sync->lock);
+
+ if (ctx)
+ ww_acquire_fini(ctx);
+
+ del_timer(&sync->timer);
+}
+
+/**
+ * is_dmabuf_sync_supported - Check if dmabuf sync is supported or not.
+ */
+bool is_dmabuf_sync_supported(void)
+{
+ return dmabuf_sync_enabled = 1;
+}
+EXPORT_SYMBOL(is_dmabuf_sync_supported);
+
+/**
+ * dmabuf_sync_init - Allocate and initialize a dmabuf sync.
+ *
+ * @priv: A device private data.
+ * @name: A sync object name.
+ *
+ * This function should be called when a device context or an event
+ * context such as a page flip event is created. And the created
+ * dmabuf_sync object should be set to the context.
+ * The caller can get a new sync object for buffer synchronization
+ * through this function.
+ */
+struct dmabuf_sync *dmabuf_sync_init(const char *name,
+ struct dmabuf_sync_priv_ops *ops,
+ void *priv)
+{
+ struct dmabuf_sync *sync;
+
+ sync = kzalloc(sizeof(*sync), GFP_KERNEL);
+ if (!sync)
+ return ERR_PTR(-ENOMEM);
+
+ strncpy(sync->name, name, ARRAY_SIZE(sync->name) - 1);
+
+ sync->ops = ops;
+ sync->priv = priv;
+ INIT_LIST_HEAD(&sync->syncs);
+ mutex_init(&sync->lock);
+ INIT_WORK(&sync->work, dmabuf_sync_timeout_worker);
+
+ return sync;
+}
+EXPORT_SYMBOL(dmabuf_sync_init);
+
+/**
+ * dmabuf_sync_fini - Release a given dmabuf sync.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_init call to release relevant resources, and after
+ * dmabuf_sync_unlock function is called.
+ */
+void dmabuf_sync_fini(struct dmabuf_sync *sync)
+{
+ if (WARN_ON(!sync))
+ return;
+
+ if (sync->ops && sync->ops->free)
+ sync->ops->free(sync->priv);
+
+ kfree(sync);
+}
+EXPORT_SYMBOL(dmabuf_sync_fini);
+
+/*
+ * dmabuf_sync_get_obj - Add a given object to syncs list.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ * @dmabuf: An object to dma_buf structure.
+ * @type: A access type to a dma buf.
+ * The DMA_BUF_ACCESS_R means that this dmabuf could be accessed by
+ * others for read access. On the other hand, the DMA_BUF_ACCESS_W
+ * means that this dmabuf couldn't be accessed by others but would be
+ * accessed by caller's dma exclusively. And the DMA_BUF_ACCESS_DMA can be
+ * combined.
+ *
+ * This function creates and initializes a new dmabuf sync object and it adds
+ * the dmabuf sync object to syncs list to track and manage all dmabufs.
+ */
+static int dmabuf_sync_get_obj(struct dmabuf_sync *sync, struct dma_buf *dmabuf,
+ unsigned int type)
+{
+ struct dmabuf_sync_object *sobj;
+
+ if (!dmabuf->sync) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
+
+ if (!IS_VALID_DMA_BUF_ACCESS_TYPE(type))
+ return -EINVAL;
+
+ if ((type & DMA_BUF_ACCESS_RW) = DMA_BUF_ACCESS_RW)
+ type &= ~DMA_BUF_ACCESS_R;
+
+ sobj = kzalloc(sizeof(*sobj), GFP_KERNEL);
+ if (!sobj) {
+ WARN_ON(1);
+ return -ENOMEM;
+ }
+
+ get_dma_buf(dmabuf);
+
+ sobj->dmabuf = dmabuf;
+ sobj->robj = dmabuf->sync;
+ sobj->access_type = type;
+
+ mutex_lock(&sync->lock);
+ list_add_tail(&sobj->head, &sync->syncs);
+ mutex_unlock(&sync->lock);
+
+ return 0;
+}
+
+/*
+ * dmabuf_sync_put_obj - Release a given sync object.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_get_obj call to release a given sync object.
+ */
+static void dmabuf_sync_put_obj(struct dmabuf_sync *sync,
+ struct dma_buf *dmabuf)
+{
+ struct dmabuf_sync_object *sobj;
+
+ mutex_lock(&sync->lock);
+
+ list_for_each_entry(sobj, &sync->syncs, head) {
+ if (sobj->dmabuf != dmabuf)
+ continue;
+
+ dma_buf_put(sobj->dmabuf);
+
+ list_del_init(&sobj->head);
+ kfree(sobj);
+ break;
+ }
+
+ if (list_empty(&sync->syncs))
+ sync->status = 0;
+
+ mutex_unlock(&sync->lock);
+}
+
+/*
+ * dmabuf_sync_put_objs - Release all sync objects of dmabuf_sync.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_get_obj call to release all sync objects.
+ */
+static void dmabuf_sync_put_objs(struct dmabuf_sync *sync)
+{
+ struct dmabuf_sync_object *sobj, *next;
+
+ mutex_lock(&sync->lock);
+
+ list_for_each_entry_safe(sobj, next, &sync->syncs, head) {
+ dma_buf_put(sobj->dmabuf);
+
+ list_del_init(&sobj->head);
+ kfree(sobj);
+ }
+
+ mutex_unlock(&sync->lock);
+
+ sync->status = 0;
+}
+
+/**
+ * dmabuf_sync_lock - lock all dmabufs added to syncs list.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * The caller should call this function prior to CPU or DMA access to
+ * the dmabufs so that others can not access the dmabufs.
+ * Internally, this function avoids dead lock issue with ww-mutex.
+ */
+int dmabuf_sync_lock(struct dmabuf_sync *sync)
+{
+ int ret;
+
+ if (!sync) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
+
+ if (list_empty(&sync->syncs))
+ return -EINVAL;
+
+ if (sync->status != DMABUF_SYNC_GOT)
+ return -EINVAL;
+
+ ret = dmabuf_sync_lock_objs(sync, &sync->ctx);
+ if (ret < 0) {
+ WARN_ON(1);
+ return ret;
+ }
+
+ sync->status = DMABUF_SYNC_LOCKED;
+
+ return ret;
+}
+EXPORT_SYMBOL(dmabuf_sync_lock);
+
+/**
+ * dmabuf_sync_unlock - unlock all objects added to syncs list.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * The caller should call this function after CPU or DMA access to
+ * the dmabufs is completed so that others can access the dmabufs.
+ */
+int dmabuf_sync_unlock(struct dmabuf_sync *sync)
+{
+ if (!sync) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
+
+ /* If current dmabuf sync object wasn't reserved then just return. */
+ if (sync->status != DMABUF_SYNC_LOCKED)
+ return -EAGAIN;
+
+ dmabuf_sync_unlock_objs(sync, &sync->ctx);
+
+ return 0;
+}
+EXPORT_SYMBOL(dmabuf_sync_unlock);
+
+/**
+ * dmabuf_sync_single_lock - lock a dma buf.
+ *
+ * @dmabuf: A dma buf object that tries to lock.
+ * @type: A access type to a dma buf.
+ * The DMA_BUF_ACCESS_R means that this dmabuf could be accessed by
+ * others for read access. On the other hand, the DMA_BUF_ACCESS_W
+ * means that this dmabuf couldn't be accessed by others but would be
+ * accessed by caller's dma exclusively. And the DMA_BUF_ACCESS_DMA can
+ * be combined with other.
+ * @wait: Indicate whether caller is blocked or not.
+ * true means that caller will be blocked, and false means that this
+ * function will return -EAGAIN if this caller can't take the lock
+ * right now.
+ *
+ * The caller should call this function prior to CPU or DMA access to the dmabuf
+ * so that others cannot access the dmabuf.
+ */
+int dmabuf_sync_single_lock(struct dma_buf *dmabuf, unsigned int type,
+ bool wait)
+{
+ struct dmabuf_sync_reservation *robj;
+
+ if (!dmabuf->sync) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
+
+ if (!IS_VALID_DMA_BUF_ACCESS_TYPE(type)) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
+ get_dma_buf(dmabuf);
+ robj = dmabuf->sync;
+
+ mutex_lock(&robj->lock);
+
+ /* Don't lock in case of read and read. */
+ if (robj->accessed_type & DMA_BUF_ACCESS_R && type & DMA_BUF_ACCESS_R) {
+ atomic_inc(&robj->shared_cnt);
+ mutex_unlock(&robj->lock);
+ return 0;
+ }
+
+ /*
+ * In case of F_SETLK, just return -EAGAIN if this dmabuf has already
+ * been locked.
+ */
+ if (!wait && robj->locked) {
+ mutex_unlock(&robj->lock);
+ dma_buf_put(dmabuf);
+ return -EAGAIN;
+ }
+
+ mutex_unlock(&robj->lock);
+
+ mutex_lock(&robj->sync_lock.base);
+
+ mutex_lock(&robj->lock);
+ robj->locked = true;
+ mutex_unlock(&robj->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL(dmabuf_sync_single_lock);
+
+/**
+ * dmabuf_sync_single_unlock - unlock a dma buf.
+ *
+ * @dmabuf: A dma buf object that tries to unlock.
+ *
+ * The caller should call this function after CPU or DMA access to
+ * the dmabuf is completed so that others can access the dmabuf.
+ */
+void dmabuf_sync_single_unlock(struct dma_buf *dmabuf)
+{
+ struct dmabuf_sync_reservation *robj;
+
+ if (!dmabuf->sync) {
+ WARN_ON(1);
+ return;
+ }
+
+ robj = dmabuf->sync;
+
+ mutex_lock(&robj->lock);
+
+ if (robj->polled) {
+ robj->poll_event = true;
+ robj->polled = false;
+ wake_up_interruptible(&robj->poll_wait);
+ }
+
+ if (atomic_add_unless(&robj->shared_cnt, -1 , 1)) {
+ mutex_unlock(&robj->lock);
+ dma_buf_put(dmabuf);
+ return;
+ }
+
+ mutex_unlock(&robj->lock);
+
+ mutex_unlock(&robj->sync_lock.base);
+
+ mutex_lock(&robj->lock);
+ robj->locked = false;
+ mutex_unlock(&robj->lock);
+
+ dma_buf_put(dmabuf);
+
+ return;
+}
+EXPORT_SYMBOL(dmabuf_sync_single_unlock);
+
+/**
+ * dmabuf_sync_get - Get dmabuf sync object.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ * @sync_buf: A dmabuf object to be synchronized with others.
+ * @type: A access type to a dma buf.
+ * The DMA_BUF_ACCESS_R means that this dmabuf could be accessed by
+ * others for read access. On the other hand, the DMA_BUF_ACCESS_W
+ * means that this dmabuf couldn't be accessed by others but would be
+ * accessed by caller's dma exclusively. And the DMA_BUF_ACCESS_DMA can
+ * be combined with other.
+ *
+ * This function should be called after dmabuf_sync_init function is called.
+ * The caller can tie up multiple dmabufs into one sync object by calling this
+ * function several times. Internally, this function allocates
+ * a dmabuf_sync_object and adds a given dmabuf to it, and also takes
+ * a reference to a dmabuf.
+ */
+int dmabuf_sync_get(struct dmabuf_sync *sync, void *sync_buf, unsigned int type)
+{
+ int ret;
+
+ if (!sync || !sync_buf) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
+
+ ret = dmabuf_sync_get_obj(sync, sync_buf, type);
+ if (ret < 0) {
+ WARN_ON(1);
+ return ret;
+ }
+
+ sync->status = DMABUF_SYNC_GOT;
+
+ return 0;
+}
+EXPORT_SYMBOL(dmabuf_sync_get);
+
+/**
+ * dmabuf_sync_put - Put dmabuf sync object to a given dmabuf.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ * @dmabuf: An dmabuf object.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_get function is called to release the dmabuf, or
+ * dmabuf_sync_unlock function is called. Internally, this function
+ * removes a given dmabuf from a sync object and remove the sync object.
+ * At this time, the dmabuf is putted.
+ */
+void dmabuf_sync_put(struct dmabuf_sync *sync, struct dma_buf *dmabuf)
+{
+ if (!sync || !dmabuf) {
+ WARN_ON(1);
+ return;
+ }
+
+ if (list_empty(&sync->syncs))
+ return;
+
+ dmabuf_sync_put_obj(sync, dmabuf);
+}
+EXPORT_SYMBOL(dmabuf_sync_put);
+
+/**
+ * dmabuf_sync_put_all - Put dmabuf sync object to dmabufs.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_get function is called to release all sync objects, or
+ * dmabuf_sync_unlock function is called. Internally, this function
+ * removes dmabufs from a sync object and remove the sync object.
+ * At this time, all dmabufs are putted.
+ */
+void dmabuf_sync_put_all(struct dmabuf_sync *sync)
+{
+ if (!sync) {
+ WARN_ON(1);
+ return;
+ }
+
+ if (list_empty(&sync->syncs))
+ return;
+
+ dmabuf_sync_put_objs(sync);
+}
+EXPORT_SYMBOL(dmabuf_sync_put_all);
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index dfac5ed..0109673 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -115,6 +115,7 @@ struct dma_buf_ops {
* @exp_name: name of the exporter; useful for debugging.
* @list_node: node for dma_buf accounting and debugging.
* @priv: exporter specific private data for this buffer object.
+ * @sync: sync object linked to this dma-buf
*/
struct dma_buf {
size_t size;
@@ -128,6 +129,7 @@ struct dma_buf {
const char *exp_name;
struct list_head list_node;
void *priv;
+ void *sync;
};
/**
@@ -148,6 +150,20 @@ struct dma_buf_attachment {
void *priv;
};
+#define DMA_BUF_ACCESS_R 0x1
+#define DMA_BUF_ACCESS_W 0x2
+#define DMA_BUF_ACCESS_DMA 0x4
+#define DMA_BUF_ACCESS_RW (DMA_BUF_ACCESS_R | DMA_BUF_ACCESS_W)
+#define DMA_BUF_ACCESS_DMA_R (DMA_BUF_ACCESS_R | DMA_BUF_ACCESS_DMA)
+#define DMA_BUF_ACCESS_DMA_W (DMA_BUF_ACCESS_W | DMA_BUF_ACCESS_DMA)
+#define DMA_BUF_ACCESS_DMA_RW (DMA_BUF_ACCESS_DMA_R | DMA_BUF_ACCESS_DMA_W)
+#define IS_VALID_DMA_BUF_ACCESS_TYPE(t) (t = DMA_BUF_ACCESS_R || \
+ t = DMA_BUF_ACCESS_W || \
+ t = DMA_BUF_ACCESS_DMA_R || \
+ t = DMA_BUF_ACCESS_DMA_W || \
+ t = DMA_BUF_ACCESS_RW || \
+ t = DMA_BUF_ACCESS_DMA_RW)
+
/**
* get_dma_buf - convenience wrapper for get_file.
* @dmabuf: [in] pointer to dma_buf
diff --git a/include/linux/dmabuf-sync.h b/include/linux/dmabuf-sync.h
new file mode 100644
index 0000000..9a3afc4
--- /dev/null
+++ b/include/linux/dmabuf-sync.h
@@ -0,0 +1,190 @@
+/*
+ * Copyright (C) 2013 Samsung Electronics Co.Ltd
+ * Authors:
+ * Inki Dae <inki.dae@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ */
+
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/dma-buf.h>
+
+enum dmabuf_sync_status {
+ DMABUF_SYNC_GOT = 1,
+ DMABUF_SYNC_LOCKED,
+};
+
+struct dmabuf_sync_reservation {
+ struct ww_mutex sync_lock;
+ struct mutex lock;
+ wait_queue_head_t poll_wait;
+ unsigned int poll_event;
+ unsigned int polled;
+ atomic_t shared_cnt;
+ unsigned int accessed_type;
+ unsigned int locked;
+};
+
+/*
+ * A structure for dmabuf_sync_object.
+ *
+ * @head: A list head to be added to syncs list.
+ * @robj: A reservation_object object.
+ * @dma_buf: A dma_buf object.
+ * @access_type: Indicate how a current task tries to access
+ * a given buffer.
+ */
+struct dmabuf_sync_object {
+ struct list_head head;
+ struct dmabuf_sync_reservation *robj;
+ struct dma_buf *dmabuf;
+ unsigned int access_type;
+};
+
+struct dmabuf_sync_priv_ops {
+ void (*free)(void *priv);
+};
+
+/*
+ * A structure for dmabuf_sync.
+ *
+ * @syncs: A list head to sync object and this is global to system.
+ * @list: A list entry used as committed list node
+ * @lock: A mutex lock to current sync object.
+ * @ctx: A current context for ww mutex.
+ * @work: A work struct to release resources at timeout.
+ * @priv: A private data.
+ * @name: A string to dmabuf sync owner.
+ * @timer: A timer list to avoid lockup and release resources.
+ * @status: Indicate current status (DMABUF_SYNC_GOT or DMABUF_SYNC_LOCKED).
+ */
+struct dmabuf_sync {
+ struct list_head syncs;
+ struct list_head list;
+ struct mutex lock;
+ struct ww_acquire_ctx ctx;
+ struct work_struct work;
+ void *priv;
+ struct dmabuf_sync_priv_ops *ops;
+ char name[64];
+ struct timer_list timer;
+ unsigned int status;
+};
+
+#ifdef CONFIG_DMABUF_SYNC
+
+extern struct ww_class dmabuf_sync_ww_class;
+
+static inline void dmabuf_sync_reservation_init(struct dma_buf *dmabuf)
+{
+ struct dmabuf_sync_reservation *obj;
+
+ obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+ if (!obj)
+ return;
+
+ dmabuf->sync = obj;
+
+ ww_mutex_init(&obj->sync_lock, &dmabuf_sync_ww_class);
+
+ mutex_init(&obj->lock);
+ atomic_set(&obj->shared_cnt, 1);
+
+ init_waitqueue_head(&obj->poll_wait);
+}
+
+static inline void dmabuf_sync_reservation_fini(struct dma_buf *dmabuf)
+{
+ struct dmabuf_sync_reservation *obj;
+
+ if (!dmabuf->sync)
+ return;
+
+ obj = dmabuf->sync;
+
+ ww_mutex_destroy(&obj->sync_lock);
+
+ kfree(obj);
+}
+
+extern bool is_dmabuf_sync_supported(void);
+
+extern struct dmabuf_sync *dmabuf_sync_init(const char *name,
+ struct dmabuf_sync_priv_ops *ops,
+ void *priv);
+
+extern void dmabuf_sync_fini(struct dmabuf_sync *sync);
+
+extern int dmabuf_sync_lock(struct dmabuf_sync *sync);
+
+extern int dmabuf_sync_unlock(struct dmabuf_sync *sync);
+
+int dmabuf_sync_single_lock(struct dma_buf *dmabuf, unsigned int type,
+ bool wait);
+
+void dmabuf_sync_single_unlock(struct dma_buf *dmabuf);
+
+extern int dmabuf_sync_get(struct dmabuf_sync *sync, void *sync_buf,
+ unsigned int type);
+
+extern void dmabuf_sync_put(struct dmabuf_sync *sync, struct dma_buf *dmabuf);
+
+extern void dmabuf_sync_put_all(struct dmabuf_sync *sync);
+
+#else
+
+static inline void dmabuf_sync_reservation_init(struct dma_buf *dmabuf) { }
+
+static inline void dmabuf_sync_reservation_fini(struct dma_buf *dmabuf) { }
+
+static inline bool is_dmabuf_sync_supported(void) { return false; }
+
+static inline struct dmabuf_sync *dmabuf_sync_init(const char *name,
+ struct dmabuf_sync_priv_ops *ops,
+ void *priv)
+{
+ return ERR_PTR(0);
+}
+
+static inline void dmabuf_sync_fini(struct dmabuf_sync *sync) { }
+
+static inline int dmabuf_sync_lock(struct dmabuf_sync *sync)
+{
+ return 0;
+}
+
+static inline int dmabuf_sync_unlock(struct dmabuf_sync *sync)
+{
+ return 0;
+}
+
+static inline int dmabuf_sync_single_lock(struct dma_buf *dmabuf,
+ unsigned int type,
+ bool wait)
+{
+ return 0;
+}
+
+static inline void dmabuf_sync_single_unlock(struct dma_buf *dmabuf)
+{
+ return;
+}
+
+static inline int dmabuf_sync_get(struct dmabuf_sync *sync,
+ void *sync_buf,
+ unsigned int type)
+{
+ return 0;
+}
+
+static inline void dmabuf_sync_put(struct dmabuf_sync *sync,
+ struct dma_buf *dmabuf) { }
+
+static inline void dmabuf_sync_put_all(struct dmabuf_sync *sync) { }
+
+#endif
--
1.7.5.4
^ permalink raw reply related
* [PATCH 2/2] [RFC PATCH v2] dma-buf: Add user interfaces for dmabuf sync support.
From: Inki Dae @ 2013-08-13 9:19 UTC (permalink / raw)
To: dri-devel, linux-fbdev, linux-arm-kernel, linux-media,
linaro-kernel
Cc: maarten.lankhorst, sumit.semwal, kyungmin.park, myungjoo.ham,
Inki Dae
In-Reply-To: <1376385576-9039-1-git-send-email-inki.dae@samsung.com>
This patch adds lock and poll callbacks to dma buf file operations,
and these callbacks will be called by fcntl and select system calls.
fcntl and select system calls can be used to wait for the completion
of DMA or CPU access to a shared dmabuf. The difference of them is
fcntl system call takes a lock after the completion but select system
call doesn't. So in case of fcntl system call, it's useful when a task
wants to access a shared dmabuf without any broken. On the other hand,
it's useful when a task wants to just wait for the completion.
Changelog v2:
- Add select system call support.
. The purpose of this feature is to wait for the completion of DMA or
CPU access to a dmabuf without that caller locks the dmabuf again
after the completion.
That is useful when caller wants to be aware of the completion of
DMA access to the dmabuf, and the caller doesn't use intefaces for
the DMA device driver.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
drivers/base/dma-buf.c | 81 +++++++++++++++++++++++++++++++++++++++++++
include/linux/dmabuf-sync.h | 1 +
2 files changed, 82 insertions(+), 0 deletions(-)
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 4aca57a..f16a396 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -29,6 +29,7 @@
#include <linux/export.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
+#include <linux/poll.h>
#include <linux/dmabuf-sync.h>
static inline int is_dma_buf_file(struct file *);
@@ -80,9 +81,89 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
return dmabuf->ops->mmap(dmabuf, vma);
}
+static unsigned int dma_buf_poll(struct file *filp,
+ struct poll_table_struct *poll)
+{
+ struct dma_buf *dmabuf;
+ struct dmabuf_sync_reservation *robj;
+ int ret = 0;
+
+ if (!is_dma_buf_file(filp))
+ return POLLERR;
+
+ dmabuf = filp->private_data;
+ if (!dmabuf || !dmabuf->sync)
+ return POLLERR;
+
+ robj = dmabuf->sync;
+
+ mutex_lock(&robj->lock);
+
+ robj->polled = true;
+
+ /*
+ * CPU or DMA access to this buffer has been completed, and
+ * the blocked task has been waked up. Return poll event
+ * so that the task can get out of select().
+ */
+ if (robj->poll_event) {
+ robj->poll_event = false;
+ mutex_unlock(&robj->lock);
+ return POLLIN | POLLOUT;
+ }
+
+ /*
+ * There is no anyone accessing this buffer so just return.
+ */
+ if (!robj->locked) {
+ mutex_unlock(&robj->lock);
+ return POLLIN | POLLOUT;
+ }
+
+ poll_wait(filp, &robj->poll_wait, poll);
+
+ mutex_unlock(&robj->lock);
+
+ return ret;
+}
+
+static int dma_buf_lock(struct file *file, int cmd, struct file_lock *fl)
+{
+ struct dma_buf *dmabuf;
+ unsigned int type;
+ bool wait = false;
+
+ if (!is_dma_buf_file(file))
+ return -EINVAL;
+
+ dmabuf = file->private_data;
+
+ if ((fl->fl_type & F_UNLCK) = F_UNLCK) {
+ dmabuf_sync_single_unlock(dmabuf);
+ return 0;
+ }
+
+ /* convert flock type to dmabuf sync type. */
+ if ((fl->fl_type & F_WRLCK) = F_WRLCK)
+ type = DMA_BUF_ACCESS_W;
+ else if ((fl->fl_type & F_RDLCK) = F_RDLCK)
+ type = DMA_BUF_ACCESS_R;
+ else
+ return -EINVAL;
+
+ if (fl->fl_flags & FL_SLEEP)
+ wait = true;
+
+ /* TODO. the locking to certain region should also be considered. */
+
+ return dmabuf_sync_single_lock(dmabuf, type, wait);
+}
+
static const struct file_operations dma_buf_fops = {
.release = dma_buf_release,
.mmap = dma_buf_mmap_internal,
+ .poll = dma_buf_poll,
+ .lock = dma_buf_lock,
};
/*
diff --git a/include/linux/dmabuf-sync.h b/include/linux/dmabuf-sync.h
index 9a3afc4..0316f68 100644
--- a/include/linux/dmabuf-sync.h
+++ b/include/linux/dmabuf-sync.h
@@ -11,6 +11,7 @@
*/
#include <linux/mutex.h>
+#include <linux/ww_mutex.h>
#include <linux/sched.h>
#include <linux/dma-buf.h>
--
1.7.5.4
^ permalink raw reply related
* Re: [PATCH 01/15] drivers: phy: add generic PHY framework
From: Kishon Vijay Abraham I @ 2013-08-13 10:56 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20130731061538.GC13289@radagast>
Hi,
On Wednesday 31 July 2013 11:45 AM, Felipe Balbi wrote:
> Hi,
>
> On Wed, Jul 31, 2013 at 11:14:32AM +0530, Kishon Vijay Abraham I wrote:
>>>>>>> IMHO we need a lookup method for PHYs, just like for clocks,
>>>>>>> regulators, PWMs or even i2c busses because there are complex cases
>>>>>>> when passing just a name using platform data will not work. I would
>>>>>>> second what Stephen said [1] and define a structure doing things in a
>>>>>>> DT-like way.
>>>>>>>
>>>>>>> Example;
>>>>>>>
>>>>>>> [platform code]
>>>>>>>
>>>>>>> static const struct phy_lookup my_phy_lookup[] = {
>>>>>>>
>>>>>>> PHY_LOOKUP("s3c-hsotg.0", "otg", "samsung-usbphy.1", "phy.2"),
>>>>>>
>>>>>> The only problem here is that if *PLATFORM_DEVID_AUTO* is used while
>>>>>> creating the device, the ids in the device name would change and
>>>>>> PHY_LOOKUP wont be useful.
>>>>>
>>>>> I don't think this is a problem. All the existing lookup methods already
>>>>> use ID to identify devices (see regulators, clkdev, PWMs, i2c, ...). You
>>>>> can simply add a requirement that the ID must be assigned manually,
>>>>> without using PLATFORM_DEVID_AUTO to use PHY lookup.
>>>>
>>>> And I'm saying that this idea, of using a specific name and id, is
>>>> frought with fragility and will break in the future in various ways when
>>>> devices get added to systems, making these strings constantly have to be
>>>> kept up to date with different board configurations.
>>>>
>>>> People, NEVER, hardcode something like an id. The fact that this
>>>> happens today with the clock code, doesn't make it right, it makes the
>>>> clock code wrong. Others have already said that this is wrong there as
>>>> well, as systems change and dynamic ids get used more and more.
>>>>
>>>> Let's not repeat the same mistakes of the past just because we refuse to
>>>> learn from them...
>>>>
>>>> So again, the "find a phy by a string" functions should be removed, the
>>>> device id should be automatically created by the phy core just to make
>>>> things unique in sysfs, and no driver code should _ever_ be reliant on
>>>> the number that is being created, and the pointer to the phy structure
>>>> should be used everywhere instead.
>>>>
>>>> With those types of changes, I will consider merging this subsystem, but
>>>> without them, sorry, I will not.
>>>
>>> I'll agree with Greg here, the very fact that we see people trying to
>>> add a requirement of *NOT* using PLATFORM_DEVID_AUTO already points to a
>>> big problem in the framework.
>>>
>>> The fact is that if we don't allow PLATFORM_DEVID_AUTO we will end up
>>> adding similar infrastructure to the driver themselves to make sure we
>>> don't end up with duplicate names in sysfs in case we have multiple
>>> instances of the same IP in the SoC (or several of the same PCIe card).
>>> I really don't want to go back to that.
>>
>> If we are using PLATFORM_DEVID_AUTO, then I dont see any way we can give the
>> correct binding information to the PHY framework. I think we can drop having
>> this non-dt support in PHY framework? I see only one platform (OMAP3) going to
>> be needing this non-dt support and we can use the USB PHY library for it.
>
> you shouldn't drop support for non-DT platform, in any case we lived
> without DT (and still do) for years. Gotta find a better way ;-)
hmm..
how about passing the device names of PHY in platform data of the controller?
It should be deterministic as the PHY framework assigns its own id and we
*don't* want to add any requirement that the ID must be assigned manually
without using PLATFORM_DEVID_AUTO. We can get rid of *phy_init_data* in the v10
patch series.
Thanks
Kishon
>
^ permalink raw reply
* Re: [PATCH 01/15] drivers: phy: add generic PHY framework
From: Tomasz Figa @ 2013-08-13 11:37 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <520A0E1C.5000306@ti.com>
On Tuesday 13 of August 2013 16:14:44 Kishon Vijay Abraham I wrote:
> Hi,
>
> On Wednesday 31 July 2013 11:45 AM, Felipe Balbi wrote:
> > Hi,
> >
> > On Wed, Jul 31, 2013 at 11:14:32AM +0530, Kishon Vijay Abraham I wrote:
> >>>>>>> IMHO we need a lookup method for PHYs, just like for clocks,
> >>>>>>> regulators, PWMs or even i2c busses because there are complex
> >>>>>>> cases
> >>>>>>> when passing just a name using platform data will not work. I
> >>>>>>> would
> >>>>>>> second what Stephen said [1] and define a structure doing things
> >>>>>>> in a
> >>>>>>> DT-like way.
> >>>>>>>
> >>>>>>> Example;
> >>>>>>>
> >>>>>>> [platform code]
> >>>>>>>
> >>>>>>> static const struct phy_lookup my_phy_lookup[] = {
> >>>>>>>
> >>>>>>> PHY_LOOKUP("s3c-hsotg.0", "otg", "samsung-usbphy.1", "phy.2"),
> >>>>>>
> >>>>>> The only problem here is that if *PLATFORM_DEVID_AUTO* is used
> >>>>>> while
> >>>>>> creating the device, the ids in the device name would change and
> >>>>>> PHY_LOOKUP wont be useful.
> >>>>>
> >>>>> I don't think this is a problem. All the existing lookup methods
> >>>>> already
> >>>>> use ID to identify devices (see regulators, clkdev, PWMs, i2c,
> >>>>> ...). You
> >>>>> can simply add a requirement that the ID must be assigned manually,
> >>>>> without using PLATFORM_DEVID_AUTO to use PHY lookup.
> >>>>
> >>>> And I'm saying that this idea, of using a specific name and id, is
> >>>> frought with fragility and will break in the future in various ways
> >>>> when
> >>>> devices get added to systems, making these strings constantly have
> >>>> to be
> >>>> kept up to date with different board configurations.
> >>>>
> >>>> People, NEVER, hardcode something like an id. The fact that this
> >>>> happens today with the clock code, doesn't make it right, it makes
> >>>> the
> >>>> clock code wrong. Others have already said that this is wrong there
> >>>> as
> >>>> well, as systems change and dynamic ids get used more and more.
> >>>>
> >>>> Let's not repeat the same mistakes of the past just because we
> >>>> refuse to
> >>>> learn from them...
> >>>>
> >>>> So again, the "find a phy by a string" functions should be removed,
> >>>> the
> >>>> device id should be automatically created by the phy core just to
> >>>> make
> >>>> things unique in sysfs, and no driver code should _ever_ be reliant
> >>>> on
> >>>> the number that is being created, and the pointer to the phy
> >>>> structure
> >>>> should be used everywhere instead.
> >>>>
> >>>> With those types of changes, I will consider merging this subsystem,
> >>>> but
> >>>> without them, sorry, I will not.
> >>>
> >>> I'll agree with Greg here, the very fact that we see people trying to
> >>> add a requirement of *NOT* using PLATFORM_DEVID_AUTO already points
> >>> to a
> >>> big problem in the framework.
> >>>
> >>> The fact is that if we don't allow PLATFORM_DEVID_AUTO we will end up
> >>> adding similar infrastructure to the driver themselves to make sure
> >>> we
> >>> don't end up with duplicate names in sysfs in case we have multiple
> >>> instances of the same IP in the SoC (or several of the same PCIe
> >>> card).
> >>> I really don't want to go back to that.
> >>
> >> If we are using PLATFORM_DEVID_AUTO, then I dont see any way we can
> >> give the correct binding information to the PHY framework. I think we
> >> can drop having this non-dt support in PHY framework? I see only one
> >> platform (OMAP3) going to be needing this non-dt support and we can
> >> use the USB PHY library for it.>
> > you shouldn't drop support for non-DT platform, in any case we lived
> > without DT (and still do) for years. Gotta find a better way ;-)
>
> hmm..
>
> how about passing the device names of PHY in platform data of the
> controller? It should be deterministic as the PHY framework assigns its
> own id and we *don't* want to add any requirement that the ID must be
> assigned manually without using PLATFORM_DEVID_AUTO. We can get rid of
> *phy_init_data* in the v10 patch series.
What about slightly altering the concept of v9 to pass a pointer to struct
device instead of device name inside phy_init_data?
Best regards,
Tomasz
^ permalink raw reply
* Re: [PATCH 01/15] drivers: phy: add generic PHY framework
From: Kishon Vijay Abraham I @ 2013-08-13 12:17 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <2034985.S0danJZqk4@amdc1227>
On Tuesday 13 August 2013 05:07 PM, Tomasz Figa wrote:
> On Tuesday 13 of August 2013 16:14:44 Kishon Vijay Abraham I wrote:
>> Hi,
>>
>> On Wednesday 31 July 2013 11:45 AM, Felipe Balbi wrote:
>>> Hi,
>>>
>>> On Wed, Jul 31, 2013 at 11:14:32AM +0530, Kishon Vijay Abraham I wrote:
>>>>>>>>> IMHO we need a lookup method for PHYs, just like for clocks,
>>>>>>>>> regulators, PWMs or even i2c busses because there are complex
>>>>>>>>> cases
>>>>>>>>> when passing just a name using platform data will not work. I
>>>>>>>>> would
>>>>>>>>> second what Stephen said [1] and define a structure doing things
>>>>>>>>> in a
>>>>>>>>> DT-like way.
>>>>>>>>>
>>>>>>>>> Example;
>>>>>>>>>
>>>>>>>>> [platform code]
>>>>>>>>>
>>>>>>>>> static const struct phy_lookup my_phy_lookup[] = {
>>>>>>>>>
>>>>>>>>> PHY_LOOKUP("s3c-hsotg.0", "otg", "samsung-usbphy.1", "phy.2"),
>>>>>>>>
>>>>>>>> The only problem here is that if *PLATFORM_DEVID_AUTO* is used
>>>>>>>> while
>>>>>>>> creating the device, the ids in the device name would change and
>>>>>>>> PHY_LOOKUP wont be useful.
>>>>>>>
>>>>>>> I don't think this is a problem. All the existing lookup methods
>>>>>>> already
>>>>>>> use ID to identify devices (see regulators, clkdev, PWMs, i2c,
>>>>>>> ...). You
>>>>>>> can simply add a requirement that the ID must be assigned manually,
>>>>>>> without using PLATFORM_DEVID_AUTO to use PHY lookup.
>>>>>>
>>>>>> And I'm saying that this idea, of using a specific name and id, is
>>>>>> frought with fragility and will break in the future in various ways
>>>>>> when
>>>>>> devices get added to systems, making these strings constantly have
>>>>>> to be
>>>>>> kept up to date with different board configurations.
>>>>>>
>>>>>> People, NEVER, hardcode something like an id. The fact that this
>>>>>> happens today with the clock code, doesn't make it right, it makes
>>>>>> the
>>>>>> clock code wrong. Others have already said that this is wrong there
>>>>>> as
>>>>>> well, as systems change and dynamic ids get used more and more.
>>>>>>
>>>>>> Let's not repeat the same mistakes of the past just because we
>>>>>> refuse to
>>>>>> learn from them...
>>>>>>
>>>>>> So again, the "find a phy by a string" functions should be removed,
>>>>>> the
>>>>>> device id should be automatically created by the phy core just to
>>>>>> make
>>>>>> things unique in sysfs, and no driver code should _ever_ be reliant
>>>>>> on
>>>>>> the number that is being created, and the pointer to the phy
>>>>>> structure
>>>>>> should be used everywhere instead.
>>>>>>
>>>>>> With those types of changes, I will consider merging this subsystem,
>>>>>> but
>>>>>> without them, sorry, I will not.
>>>>>
>>>>> I'll agree with Greg here, the very fact that we see people trying to
>>>>> add a requirement of *NOT* using PLATFORM_DEVID_AUTO already points
>>>>> to a
>>>>> big problem in the framework.
>>>>>
>>>>> The fact is that if we don't allow PLATFORM_DEVID_AUTO we will end up
>>>>> adding similar infrastructure to the driver themselves to make sure
>>>>> we
>>>>> don't end up with duplicate names in sysfs in case we have multiple
>>>>> instances of the same IP in the SoC (or several of the same PCIe
>>>>> card).
>>>>> I really don't want to go back to that.
>>>>
>>>> If we are using PLATFORM_DEVID_AUTO, then I dont see any way we can
>>>> give the correct binding information to the PHY framework. I think we
>>>> can drop having this non-dt support in PHY framework? I see only one
>>>> platform (OMAP3) going to be needing this non-dt support and we can
>>>> use the USB PHY library for it.>
>>> you shouldn't drop support for non-DT platform, in any case we lived
>>> without DT (and still do) for years. Gotta find a better way ;-)
>>
>> hmm..
>>
>> how about passing the device names of PHY in platform data of the
>> controller? It should be deterministic as the PHY framework assigns its
>> own id and we *don't* want to add any requirement that the ID must be
>> assigned manually without using PLATFORM_DEVID_AUTO. We can get rid of
>> *phy_init_data* in the v10 patch series.
>
> What about slightly altering the concept of v9 to pass a pointer to struct
> device instead of device name inside phy_init_data?
The problem is device might be created very late. (For example in omap4, usb2
phy device gets created when ocp2scp bus is probed). And we have to pass the
init data in board file.
Thanks
Kishon
^ permalink raw reply
* [Resend][RFC PATCH v6 0/2] Introduce buffer synchronization framework
From: Inki Dae @ 2013-08-13 12:56 UTC (permalink / raw)
To: dri-devel, linux-fbdev, linux-arm-kernel, linux-media,
linaro-kernel
Cc: maarten.lankhorst, sumit.semwal, kyungmin.park, myungjoo.ham
In-Reply-To: <1376385576-9039-1-git-send-email-inki.dae@samsung.com>
Just adding more detailed descriptions.
Hi all,
This patch set introduces a buffer synchronization framework based
on DMA BUF[1] and based on ww-mutexes[2] for lock mechanism, and
may be final RFC.
The purpose of this framework is to provide not only buffer access
control to CPU and CPU, and CPU and DMA, and DMA and DMA but also
easy-to-use interfaces for device drivers and user application.
In addtion, this patch set suggests a way for enhancing performance.
For generic user mode interface, we have used fcntl and select system
call[3]. As you know, user application sees a buffer object as a dma-buf
file descriptor. So fcntl() call with the file descriptor means to lock
some buffer region being managed by the dma-buf object. And select() call
means to wait for the completion of CPU or DMA access to the dma-buf
without locking. For more detail, you can refer to the dma-buf-sync.txt
in Documentation/
There are some cases we should use this buffer synchronization framework.
One of which is to primarily enhance GPU rendering performance on Tizen
platform in case of 3d app with compositing mode that 3d app draws
something in off-screen buffer, and Web app.
In case of 3d app with compositing mode which is not a full screen mode,
the app calls glFlush to submit 3d commands to GPU driver instead of
glFinish for more performance. The reason we call glFlush is that glFinish
blocks caller's task until the execution of the 2d commands is completed.
Thus, that makes GPU and CPU more idle. As result, 3d rendering performance
with glFinish is quite lower than glFlush. However, the use of glFlush has
one issue that the a buffer shared with GPU could be broken when CPU
accesses the buffer at once after glFlush because CPU cannot be aware of
the completion of GPU access to the buffer. Of course, the app can be aware
of that time using eglWaitGL but this function is valid only in case of the
same process.
The below summarizes how app's window is displayed on Tizen platform:
1. X client requests a window buffer to Xorg.
2. X client draws something in the window buffer using CPU.
3. X client requests SWAP to Xorg.
4. Xorg notifies a damage event to Composite Manager.
5. Composite Manager gets the window buffer (front buffer) through
DRI2GetBuffers.
6. Composite Manager composes the window buffer and its own back buffer
using GPU. At this time, eglSwapBuffers is called: internally, 3d
commands are flushed to gpu driver.
7. Composite Manager requests SWAP to Xorg.
8. Xorg performs drm page flip. At this time, the window buffer is
displayed on screen.
Web app based on HTML5 also has similar procedure. Web browser and its web
app are different processs. Web app draws something in its own buffer,
and then the web browser gets a window buffer from Xorg, and then composes
those two buffers using GPU.
Thus, in such cases, a shared buffer could be broken when one process draws
something in a shared buffer using CPU while Composite manager is composing
two buffers - X client's front buffer and Composite manger's back buffer, or
web app's front buffer and web browser's back buffer - using GPU without
any locking mechanism. That is why we need user land locking interface,
fcntl system call.
And last one is a deferred page flip issue. This issue is that a window
buffer rendered can be displayed on screen in about 32ms in worst case:
assume that the gpu rendering is completed within 16ms.
That can be incurred when compositing a pixmap buffer with a window buffer
using GPU and when vsync is just started. At this time, Xorg waits for
a vblank event to get a window buffer so 3d rendering will be delayed
up to about 16ms. As a result, the window buffer would be displayed in
about two vsyncs (about 32ms) and in turn, that would show slow
responsiveness.
For this, we could enhance the responsiveness with locking
mechanism: skipping one vblank wait. I guess in the similar reason,
Android, Chrome OS, and other platforms are using their own locking
mechanisms; Android sync driver, KDS, and DMA fence.
The below shows the deferred page flip issue in worst case,
|------------ <- vsync signal
|<------ DRI2GetBuffers
|
|
|
|------------ <- vsync signal
|<------ Request gpu rendering
time |
|
|<------ Request page flip (deferred)
|------------ <- vsync signal
|<------ Displayed on screen
|
|
|
|------------ <- vsync signal
Thanks,
Inki Dae
References:
[1] http://lwn.net/Articles/470339/
[2] https://patchwork.kernel.org/patch/2625361/
[3] http://linux.die.net/man/2/fcntl
Inki Dae (2):
[RFC PATCH v6] dmabuf-sync: Add a buffer synchronization framework
[RFC PATCH v2] dma-buf: Add user interfaces for dmabuf sync support.
Documentation/dma-buf-sync.txt | 285 +++++++++++++++++
drivers/base/Kconfig | 7 +
drivers/base/Makefile | 1 +
drivers/base/dma-buf.c | 85 +++++
drivers/base/dmabuf-sync.c | 678 ++++++++++++++++++++++++++++++++++++++++
include/linux/dma-buf.h | 16 +
include/linux/dmabuf-sync.h | 191 +++++++++++
7 files changed, 1263 insertions(+), 0 deletions(-)
create mode 100644 Documentation/dma-buf-sync.txt
create mode 100644 drivers/base/dmabuf-sync.c
create mode 100644 include/linux/dmabuf-sync.h
--
1.7.5.4
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^ permalink raw reply
* Re: [RFC 1/1] drm/pl111: Initial drm/kms driver for pl111
From: Rob Clark @ 2013-08-13 14:58 UTC (permalink / raw)
To: Tom Cooksey
Cc: linux-arm-kernel, linux-fbdev, Pawel Moll, dri-devel,
Daniel Vetter
In-Reply-To: <520a4435.070a0e0a.4fce.ffff9731SMTPIN_ADDED_BROKEN@mx.google.com>
On Tue, Aug 13, 2013 at 10:35 AM, Tom Cooksey <tom.cooksey@arm.com> wrote:
>> > > > So in the above, after X receives the second DRI2SwapBuffers, it
>> > > > doesn't need to get scheduled again for the next frame to be both
>> > > > rendered by the GPU and issued to the display for scanout.
>> > >
>> > > well, this is really only an issue if you are so loaded that you
>> > > don't get a chance to schedule for ~16ms.. which is pretty long
>> > > time.
>>
>> Yes - it really is 16ms (minus interrupt/workqueue latency) isn't it?
>> Hmmm, that does sound very long. Will try out some experiments and see.
>
> We're looking at moving the flip queue into the DDX driver, however
> it's not as straight-forward as I thought. With the current design,
> all rate-limiting happens on the client side. So even if you only have
> double buffering, using KDS you can queue up as many asynchronous
> GPU-render/scan-out pairs as you want. It's up to EGL in the client
> application to figure out there's a lot of frames in-flight and so
> should probably block the application's render thread in
> eglSwapBuffers to let the GPU and/or display catch up a bit.
>
> If we only allow a single outstanding page-flip job in DRM, there'd be
> a race if we returned a buffer to the client which had an outstanding
> page-flip queued up in the DDX: The client could issue a render job to
> the buffer just as the DDX processed the page-flip from the queue,
> making the scan-out block until the GPU rendered the next frame. It
> would also mean the previous frame would have been lost as it never
> got scanned out before the GPU rendered the next-next frame to it.
You wouldn't unconditionally send the swap-done event to the client
when the queue is "full". (Well, for omap and msm, the queue depth is
1, for triple buffer.. I think usually you don't want to do more than
triple buffer.) The client would never get a buffer that wasn't
already done being scanned out, so there shouldn't be a race.
Basically, in DDX, when you get a ScheduleSwap, there are two cases:
1) you are still waiting for previous page-flip event from kernel, in
which case you queue the swap and don't immediately send the event
back to the client. When the previous page flip completes, you
schedule the new one and then send back the event to the client.
2) you are not waiting for a previous page-flip, in which case you
schedule the new page-flip and send the event to the client.
(I hope that is clear.. I suppose maybe a picture here would help, but
sadly I don't have anything handy)
The potential drawback is that the client doesn't necessarily have any
control over double vs triple buffering. In omap ddx I solved this by
adding a special attachment point that the client could request to
tell the DDX that it wanted to triple buffer. But the upside is that
you never need to worry about a modeset when there is more than one
flip pending.
BR,
-R
> So instead, I think we'll have to block (suspend?) a client in
> ScheduleSwap if the next buffer it would obtain with DRI2GetBuffers
> has an outstanding page-flip in the user-space queue. We then wake
> the client up again _after_ we get the page-flip event for the
> previous page flip and have issued the page-flip to the next buffer
> to the DRM. That way the DRM display driver has already registered its
> intention to use the buffer with KDS before the client ever gets hold
> of it.
>
> Note: I say KDS here, but I assume the same issues will apply on any
> implicit buffer-based synchronization. I.e. dma-fence.
>
> It's not really a problem I don't think, but mention it to see if you
> can see a reason why the above wouldn't work before we go and
> implement it - it's a fairly big change to the DDX. Can you see any
> issues with it? PrepareAccess gets interesting...
>
>
>
> Cheers,
>
> Tom
>
>
>
>
>
^ permalink raw reply
* Re: [PATCH 01/15] drivers: phy: add generic PHY framework
From: Sylwester Nawrocki @ 2013-08-13 22:19 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <520A2100.6000709@ti.com>
W dniu 2013-08-13 14:05, Kishon Vijay Abraham I pisze:
> On Tuesday 13 August 2013 05:07 PM, Tomasz Figa wrote:
>> On Tuesday 13 of August 2013 16:14:44 Kishon Vijay Abraham I wrote:
>>> On Wednesday 31 July 2013 11:45 AM, Felipe Balbi wrote:
>>>> On Wed, Jul 31, 2013 at 11:14:32AM +0530, Kishon Vijay Abraham I wrote:
>>>>>>>>>> IMHO we need a lookup method for PHYs, just like for clocks,
>>>>>>>>>> regulators, PWMs or even i2c busses because there are complex
>>>>>>>>>> cases
>>>>>>>>>> when passing just a name using platform data will not work. I
>>>>>>>>>> would
>>>>>>>>>> second what Stephen said [1] and define a structure doing things
>>>>>>>>>> in a
>>>>>>>>>> DT-like way.
>>>>>>>>>>
>>>>>>>>>> Example;
>>>>>>>>>>
>>>>>>>>>> [platform code]
>>>>>>>>>>
>>>>>>>>>> static const struct phy_lookup my_phy_lookup[] = {
>>>>>>>>>>
>>>>>>>>>> PHY_LOOKUP("s3c-hsotg.0", "otg", "samsung-usbphy.1", "phy.2"),
>>>>>>>>>
>>>>>>>>> The only problem here is that if *PLATFORM_DEVID_AUTO* is used
>>>>>>>>> while
>>>>>>>>> creating the device, the ids in the device name would change and
>>>>>>>>> PHY_LOOKUP wont be useful.
>>>>>>>>
>>>>>>>> I don't think this is a problem. All the existing lookup methods
>>>>>>>> already
>>>>>>>> use ID to identify devices (see regulators, clkdev, PWMs, i2c,
>>>>>>>> ...). You
>>>>>>>> can simply add a requirement that the ID must be assigned manually,
>>>>>>>> without using PLATFORM_DEVID_AUTO to use PHY lookup.
>>>>>>>
>>>>>>> And I'm saying that this idea, of using a specific name and id, is
>>>>>>> frought with fragility and will break in the future in various ways
>>>>>>> when
>>>>>>> devices get added to systems, making these strings constantly have
>>>>>>> to be
>>>>>>> kept up to date with different board configurations.
>>>>>>>
>>>>>>> People, NEVER, hardcode something like an id. The fact that this
>>>>>>> happens today with the clock code, doesn't make it right, it makes
>>>>>>> the
>>>>>>> clock code wrong. Others have already said that this is wrong there
>>>>>>> as
>>>>>>> well, as systems change and dynamic ids get used more and more.
>>>>>>>
>>>>>>> Let's not repeat the same mistakes of the past just because we
>>>>>>> refuse to
>>>>>>> learn from them...
>>>>>>>
>>>>>>> So again, the "find a phy by a string" functions should be removed,
>>>>>>> the
>>>>>>> device id should be automatically created by the phy core just to
>>>>>>> make
>>>>>>> things unique in sysfs, and no driver code should _ever_ be reliant
>>>>>>> on
>>>>>>> the number that is being created, and the pointer to the phy
>>>>>>> structure
>>>>>>> should be used everywhere instead.
>>>>>>>
>>>>>>> With those types of changes, I will consider merging this subsystem,
>>>>>>> but
>>>>>>> without them, sorry, I will not.
>>>>>>
>>>>>> I'll agree with Greg here, the very fact that we see people trying to
>>>>>> add a requirement of *NOT* using PLATFORM_DEVID_AUTO already points
>>>>>> to a big problem in the framework.
>>>>>>
>>>>>> The fact is that if we don't allow PLATFORM_DEVID_AUTO we will end up
>>>>>> adding similar infrastructure to the driver themselves to make sure
>>>>>> we
>>>>>> don't end up with duplicate names in sysfs in case we have multiple
>>>>>> instances of the same IP in the SoC (or several of the same PCIe
>>>>>> card).
>>>>>> I really don't want to go back to that.
>>>>>
>>>>> If we are using PLATFORM_DEVID_AUTO, then I dont see any way we can
>>>>> give the correct binding information to the PHY framework. I think we
>>>>> can drop having this non-dt support in PHY framework? I see only one
>>>>> platform (OMAP3) going to be needing this non-dt support and we can
>>>>> use the USB PHY library for it.>
>>>> you shouldn't drop support for non-DT platform, in any case we lived
>>>> without DT (and still do) for years. Gotta find a better way ;-)
>>>
>>> hmm..
>>>
>>> how about passing the device names of PHY in platform data of the
>>> controller? It should be deterministic as the PHY framework assigns its
>>> own id and we *don't* want to add any requirement that the ID must be
>>> assigned manually without using PLATFORM_DEVID_AUTO. We can get rid of
>>> *phy_init_data* in the v10 patch series.
OK, so the PHY device name would have a fixed part, passed as
platform data of the controller and a variable part appended
by the PHY core, depending on the number of registered PHYs ?
Then same PHY names would be passed as the PHY provider driver's
platform data ?
Then if there are 2 instances of the above (same names in platform
data) how would be determined which PHY controller is linked to
which PHY supplier ?
I guess you want each device instance to have different PHY device
names already in platform data ? That might work. We probably will
be focused mostly on DT anyway. It seem without DT we are trying
to find some layer that would allow us to couple relevant devices
and overcome driver core inconvenience that it provides to means
to identify specific devices in advance. :) Your proposal sounds
reasonable, however I might be missing some details or corner cases.
>> What about slightly altering the concept of v9 to pass a pointer to struct
>> device instead of device name inside phy_init_data?
As Felipe said, we don't want to pass pointers in platform_data
to/from random subsystems. We pass data, passing pointers would
be a total mess IMHO.
> The problem is device might be created very late. (For example in omap4, usb2
> phy device gets created when ocp2scp bus is probed). And we have to pass the
> init data in board file.
Regards,
Sylwester
^ permalink raw reply
* Re: [PATCH 01/15] drivers: phy: add generic PHY framework
From: Tomasz Figa @ 2013-08-13 23:04 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <520AB0F0.8010106@gmail.com>
On Wednesday 14 of August 2013 00:19:28 Sylwester Nawrocki wrote:
> W dniu 2013-08-13 14:05, Kishon Vijay Abraham I pisze:
> > On Tuesday 13 August 2013 05:07 PM, Tomasz Figa wrote:
> >> On Tuesday 13 of August 2013 16:14:44 Kishon Vijay Abraham I wrote:
> >>> On Wednesday 31 July 2013 11:45 AM, Felipe Balbi wrote:
> >>>> On Wed, Jul 31, 2013 at 11:14:32AM +0530, Kishon Vijay Abraham I
wrote:
> >>>>>>>>>> IMHO we need a lookup method for PHYs, just like for clocks,
> >>>>>>>>>> regulators, PWMs or even i2c busses because there are complex
> >>>>>>>>>> cases
> >>>>>>>>>> when passing just a name using platform data will not work. I
> >>>>>>>>>> would
> >>>>>>>>>> second what Stephen said [1] and define a structure doing
> >>>>>>>>>> things
> >>>>>>>>>> in a
> >>>>>>>>>> DT-like way.
> >>>>>>>>>>
> >>>>>>>>>> Example;
> >>>>>>>>>>
> >>>>>>>>>> [platform code]
> >>>>>>>>>>
> >>>>>>>>>> static const struct phy_lookup my_phy_lookup[] = {
> >>>>>>>>>>
> >>>>>>>>>> PHY_LOOKUP("s3c-hsotg.0", "otg", "samsung-usbphy.1",
> >>>>>>>>>> "phy.2"),
> >>>>>>>>>
> >>>>>>>>> The only problem here is that if *PLATFORM_DEVID_AUTO* is used
> >>>>>>>>> while
> >>>>>>>>> creating the device, the ids in the device name would change
> >>>>>>>>> and
> >>>>>>>>> PHY_LOOKUP wont be useful.
> >>>>>>>>
> >>>>>>>> I don't think this is a problem. All the existing lookup
> >>>>>>>> methods
> >>>>>>>> already
> >>>>>>>> use ID to identify devices (see regulators, clkdev, PWMs, i2c,
> >>>>>>>> ...). You
> >>>>>>>> can simply add a requirement that the ID must be assigned
> >>>>>>>> manually,
> >>>>>>>> without using PLATFORM_DEVID_AUTO to use PHY lookup.
> >>>>>>>
> >>>>>>> And I'm saying that this idea, of using a specific name and id,
> >>>>>>> is
> >>>>>>> frought with fragility and will break in the future in various
> >>>>>>> ways
> >>>>>>> when
> >>>>>>> devices get added to systems, making these strings constantly
> >>>>>>> have
> >>>>>>> to be
> >>>>>>> kept up to date with different board configurations.
> >>>>>>>
> >>>>>>> People, NEVER, hardcode something like an id. The fact that
> >>>>>>> this
> >>>>>>> happens today with the clock code, doesn't make it right, it
> >>>>>>> makes
> >>>>>>> the
> >>>>>>> clock code wrong. Others have already said that this is wrong
> >>>>>>> there
> >>>>>>> as
> >>>>>>> well, as systems change and dynamic ids get used more and more.
> >>>>>>>
> >>>>>>> Let's not repeat the same mistakes of the past just because we
> >>>>>>> refuse to
> >>>>>>> learn from them...
> >>>>>>>
> >>>>>>> So again, the "find a phy by a string" functions should be
> >>>>>>> removed,
> >>>>>>> the
> >>>>>>> device id should be automatically created by the phy core just
> >>>>>>> to
> >>>>>>> make
> >>>>>>> things unique in sysfs, and no driver code should _ever_ be
> >>>>>>> reliant
> >>>>>>> on
> >>>>>>> the number that is being created, and the pointer to the phy
> >>>>>>> structure
> >>>>>>> should be used everywhere instead.
> >>>>>>>
> >>>>>>> With those types of changes, I will consider merging this
> >>>>>>> subsystem,
> >>>>>>> but
> >>>>>>> without them, sorry, I will not.
> >>>>>>
> >>>>>> I'll agree with Greg here, the very fact that we see people
> >>>>>> trying to
> >>>>>> add a requirement of *NOT* using PLATFORM_DEVID_AUTO already
> >>>>>> points
> >>>>>> to a big problem in the framework.
> >>>>>>
> >>>>>> The fact is that if we don't allow PLATFORM_DEVID_AUTO we will
> >>>>>> end up
> >>>>>> adding similar infrastructure to the driver themselves to make
> >>>>>> sure
> >>>>>> we
> >>>>>> don't end up with duplicate names in sysfs in case we have
> >>>>>> multiple
> >>>>>> instances of the same IP in the SoC (or several of the same PCIe
> >>>>>> card).
> >>>>>> I really don't want to go back to that.
> >>>>>
> >>>>> If we are using PLATFORM_DEVID_AUTO, then I dont see any way we
> >>>>> can
> >>>>> give the correct binding information to the PHY framework. I think
> >>>>> we
> >>>>> can drop having this non-dt support in PHY framework? I see only
> >>>>> one
> >>>>> platform (OMAP3) going to be needing this non-dt support and we
> >>>>> can
> >>>>> use the USB PHY library for it.>
> >>>>
> >>>> you shouldn't drop support for non-DT platform, in any case we
> >>>> lived
> >>>> without DT (and still do) for years. Gotta find a better way ;-)
> >>>
> >>> hmm..
> >>>
> >>> how about passing the device names of PHY in platform data of the
> >>> controller? It should be deterministic as the PHY framework assigns
> >>> its
> >>> own id and we *don't* want to add any requirement that the ID must
> >>> be
> >>> assigned manually without using PLATFORM_DEVID_AUTO. We can get rid
> >>> of
> >>> *phy_init_data* in the v10 patch series.
>
> OK, so the PHY device name would have a fixed part, passed as
> platform data of the controller and a variable part appended
> by the PHY core, depending on the number of registered PHYs ?
>
> Then same PHY names would be passed as the PHY provider driver's
> platform data ?
>
> Then if there are 2 instances of the above (same names in platform
> data) how would be determined which PHY controller is linked to
> which PHY supplier ?
>
> I guess you want each device instance to have different PHY device
> names already in platform data ? That might work. We probably will
> be focused mostly on DT anyway. It seem without DT we are trying
> to find some layer that would allow us to couple relevant devices
> and overcome driver core inconvenience that it provides to means
> to identify specific devices in advance. :) Your proposal sounds
> reasonable, however I might be missing some details or corner cases.
>
> >> What about slightly altering the concept of v9 to pass a pointer to
> >> struct device instead of device name inside phy_init_data?
>
> As Felipe said, we don't want to pass pointers in platform_data
> to/from random subsystems. We pass data, passing pointers would
> be a total mess IMHO.
Well, this is a total mess anyway... I don't really get the point of using
PLATFORM_DEVID_AUTO. The only thing that comes to my mind is that you can
use it if you don't care about the ID and so it can be assigned
automatically.
However my understanding of the device ID is that it was supposed to
provide a way to identify multiple instances of identical devices in a
reliable way, to solve problems like the one we are trying to solve
here...
So maybe let's stop solving an already solved problem and just state that
you need to explicitly assign device ID to use this framework?
Best regards,
Tomasz
^ permalink raw reply
* RE: [PATCH V6 1/4] ARM: dts: Add DP PHY node to exynos5250.dtsi
From: Kukjin Kim @ 2013-08-14 8:21 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <003e01ce7c7a$e519a300$af4ce900$@samsung.com>
Jingoo Han wrote:
>
> Add PHY provider node for the DP PHY.
>
> Signed-off-by: Jingoo Han <jg1.han@samsung.com>
> Reviewed-by: Tomasz Figa <t.figa@samsung.com>
> Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Thanks,
Kukjin
> ---
> arch/arm/boot/dts/exynos5250.dtsi | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/boot/dts/exynos5250.dtsi
> b/arch/arm/boot/dts/exynos5250.dtsi
> index fc9fb3d..c326c06 100644
> --- a/arch/arm/boot/dts/exynos5250.dtsi
> +++ b/arch/arm/boot/dts/exynos5250.dtsi
> @@ -616,6 +616,12 @@
> interrupts = <0 94 0>;
> };
>
> + dp_phy: video-phy@10040720 {
> + compatible = "samsung,exynos5250-dp-video-phy";
> + reg = <0x10040720 4>;
> + #phy-cells = <0>;
> + };
> +
> dp-controller {
> compatible = "samsung,exynos5-dp";
> reg = <0x145b0000 0x1000>;
> @@ -623,11 +629,8 @@
> interrupt-parent = <&combiner>;
> #address-cells = <1>;
> #size-cells = <0>;
> -
> - dptx-phy {
> - reg = <0x10040720>;
> - samsung,enable-mask = <1>;
> - };
> + phys = <&dp_phy>;
> + phy-names = "dp";
> };
>
> fimd {
> --
> 1.7.10.4
^ permalink raw reply
* [PATCH 0/29] simplify use of devm_ioremap_resource
From: Julia Lawall @ 2013-08-14 9:11 UTC (permalink / raw)
To: dri-devel
Cc: alsa-devel, kernel-janitors, linux-fbdev, linux-ide, linux-mtd,
linux-i2c, linux-samsung-soc, linux-scsi, linux-serial,
linux-input, linux-media, linux-pwm, linux-watchdog, rtc-linux,
linux-pm, linux-gpio, linux-tegra, linux-omap, linux-arm-kernel,
linux-usb, linux-kernel, linux-spi
devm_ioremap_resource often uses the result of a call to
platform_get_resource as its last argument. devm_ioremap_resource does
appropriate error handling on this argument, so error handling can be
removed from the call site. To make the connection between the call to
platform_get_resource and the call to devm_ioremap_resource more clear, the
former is also moved down to be adjacent to the latter.
In many cases, this patch changes the specific error value that is
returned on failure of platform_get_resource.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression pdev,res,n,e,e1;
expression ret != 0;
identifier l;
@@
(
res = platform_get_resource(pdev, IORESOURCE_MEM, n);
- if (res = NULL) { ... \(goto l;\|return ret;\) }
e = devm_ioremap_resource(e1, res);
|
- res = platform_get_resource(pdev, IORESOURCE_MEM, n);
... when != res
- if (res = NULL) { ... \(goto l;\|return ret;\) }
... when != res
+ res = platform_get_resource(pdev, IORESOURCE_MEM, n);
e = devm_ioremap_resource(e1, res);
)
// </smpl>
^ permalink raw reply
* [PATCH 2/29] video: mxsfb: simplify use of devm_ioremap_resource
From: Julia Lawall @ 2013-08-14 9:11 UTC (permalink / raw)
To: Jean-Christophe Plagniol-Villard
Cc: kernel-janitors, Tomi Valkeinen, linux-fbdev, linux-kernel
In-Reply-To: <1376471493-22215-1-git-send-email-Julia.Lawall@lip6.fr>
From: Julia Lawall <Julia.Lawall@lip6.fr>
Remove unneeded error handling on the result of a call to
platform_get_resource when the value is passed to devm_ioremap_resource.
Move the call to platform_get_resource adjacent to the call to
devm_ioremap_resource to make the connection between them more clear.
A simplified version of the semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@@
expression pdev,res,n,e,e1;
expression ret != 0;
identifier l;
@@
- res = platform_get_resource(pdev, IORESOURCE_MEM, n);
... when != res
- if (res = NULL) { ... \(goto l;\|return ret;\) }
... when != res
+ res = platform_get_resource(pdev, IORESOURCE_MEM, n);
e = devm_ioremap_resource(e1, res);
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
---
drivers/video/mxsfb.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
index c2d3514..d250ed0 100644
--- a/drivers/video/mxsfb.c
+++ b/drivers/video/mxsfb.c
@@ -855,12 +855,6 @@ static int mxsfb_probe(struct platform_device *pdev)
if (of_id)
pdev->id_entry = of_id->data;
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!res) {
- dev_err(&pdev->dev, "Cannot get memory IO resource\n");
- return -ENODEV;
- }
-
fb_info = framebuffer_alloc(sizeof(struct mxsfb_info), &pdev->dev);
if (!fb_info) {
dev_err(&pdev->dev, "Failed to allocate fbdev\n");
@@ -869,6 +863,7 @@ static int mxsfb_probe(struct platform_device *pdev)
host = to_imxfb_host(fb_info);
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
host->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(host->base)) {
ret = PTR_ERR(host->base);
^ permalink raw reply related
* Re: [PATCH 01/15] drivers: phy: add generic PHY framework
From: Kishon Vijay Abraham I @ 2013-08-14 15:17 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <2128883.KpgODjXPJQ@flatron>
Hi,
On Wednesday 14 August 2013 04:34 AM, Tomasz Figa wrote:
> On Wednesday 14 of August 2013 00:19:28 Sylwester Nawrocki wrote:
>> W dniu 2013-08-13 14:05, Kishon Vijay Abraham I pisze:
>>> On Tuesday 13 August 2013 05:07 PM, Tomasz Figa wrote:
>>>> On Tuesday 13 of August 2013 16:14:44 Kishon Vijay Abraham I wrote:
>>>>> On Wednesday 31 July 2013 11:45 AM, Felipe Balbi wrote:
>>>>>> On Wed, Jul 31, 2013 at 11:14:32AM +0530, Kishon Vijay Abraham I
> wrote:
>>>>>>>>>>>> IMHO we need a lookup method for PHYs, just like for clocks,
>>>>>>>>>>>> regulators, PWMs or even i2c busses because there are complex
>>>>>>>>>>>> cases
>>>>>>>>>>>> when passing just a name using platform data will not work. I
>>>>>>>>>>>> would
>>>>>>>>>>>> second what Stephen said [1] and define a structure doing
>>>>>>>>>>>> things
>>>>>>>>>>>> in a
>>>>>>>>>>>> DT-like way.
>>>>>>>>>>>>
>>>>>>>>>>>> Example;
>>>>>>>>>>>>
>>>>>>>>>>>> [platform code]
>>>>>>>>>>>>
>>>>>>>>>>>> static const struct phy_lookup my_phy_lookup[] = {
>>>>>>>>>>>>
>>>>>>>>>>>> PHY_LOOKUP("s3c-hsotg.0", "otg", "samsung-usbphy.1",
>>>>>>>>>>>> "phy.2"),
>>>>>>>>>>>
>>>>>>>>>>> The only problem here is that if *PLATFORM_DEVID_AUTO* is used
>>>>>>>>>>> while
>>>>>>>>>>> creating the device, the ids in the device name would change
>>>>>>>>>>> and
>>>>>>>>>>> PHY_LOOKUP wont be useful.
>>>>>>>>>>
>>>>>>>>>> I don't think this is a problem. All the existing lookup
>>>>>>>>>> methods
>>>>>>>>>> already
>>>>>>>>>> use ID to identify devices (see regulators, clkdev, PWMs, i2c,
>>>>>>>>>> ...). You
>>>>>>>>>> can simply add a requirement that the ID must be assigned
>>>>>>>>>> manually,
>>>>>>>>>> without using PLATFORM_DEVID_AUTO to use PHY lookup.
>>>>>>>>>
>>>>>>>>> And I'm saying that this idea, of using a specific name and id,
>>>>>>>>> is
>>>>>>>>> frought with fragility and will break in the future in various
>>>>>>>>> ways
>>>>>>>>> when
>>>>>>>>> devices get added to systems, making these strings constantly
>>>>>>>>> have
>>>>>>>>> to be
>>>>>>>>> kept up to date with different board configurations.
>>>>>>>>>
>>>>>>>>> People, NEVER, hardcode something like an id. The fact that
>>>>>>>>> this
>>>>>>>>> happens today with the clock code, doesn't make it right, it
>>>>>>>>> makes
>>>>>>>>> the
>>>>>>>>> clock code wrong. Others have already said that this is wrong
>>>>>>>>> there
>>>>>>>>> as
>>>>>>>>> well, as systems change and dynamic ids get used more and more.
>>>>>>>>>
>>>>>>>>> Let's not repeat the same mistakes of the past just because we
>>>>>>>>> refuse to
>>>>>>>>> learn from them...
>>>>>>>>>
>>>>>>>>> So again, the "find a phy by a string" functions should be
>>>>>>>>> removed,
>>>>>>>>> the
>>>>>>>>> device id should be automatically created by the phy core just
>>>>>>>>> to
>>>>>>>>> make
>>>>>>>>> things unique in sysfs, and no driver code should _ever_ be
>>>>>>>>> reliant
>>>>>>>>> on
>>>>>>>>> the number that is being created, and the pointer to the phy
>>>>>>>>> structure
>>>>>>>>> should be used everywhere instead.
>>>>>>>>>
>>>>>>>>> With those types of changes, I will consider merging this
>>>>>>>>> subsystem,
>>>>>>>>> but
>>>>>>>>> without them, sorry, I will not.
>>>>>>>>
>>>>>>>> I'll agree with Greg here, the very fact that we see people
>>>>>>>> trying to
>>>>>>>> add a requirement of *NOT* using PLATFORM_DEVID_AUTO already
>>>>>>>> points
>>>>>>>> to a big problem in the framework.
>>>>>>>>
>>>>>>>> The fact is that if we don't allow PLATFORM_DEVID_AUTO we will
>>>>>>>> end up
>>>>>>>> adding similar infrastructure to the driver themselves to make
>>>>>>>> sure
>>>>>>>> we
>>>>>>>> don't end up with duplicate names in sysfs in case we have
>>>>>>>> multiple
>>>>>>>> instances of the same IP in the SoC (or several of the same PCIe
>>>>>>>> card).
>>>>>>>> I really don't want to go back to that.
>>>>>>>
>>>>>>> If we are using PLATFORM_DEVID_AUTO, then I dont see any way we
>>>>>>> can
>>>>>>> give the correct binding information to the PHY framework. I think
>>>>>>> we
>>>>>>> can drop having this non-dt support in PHY framework? I see only
>>>>>>> one
>>>>>>> platform (OMAP3) going to be needing this non-dt support and we
>>>>>>> can
>>>>>>> use the USB PHY library for it.>
>>>>>>
>>>>>> you shouldn't drop support for non-DT platform, in any case we
>>>>>> lived
>>>>>> without DT (and still do) for years. Gotta find a better way ;-)
>>>>>
>>>>> hmm..
>>>>>
>>>>> how about passing the device names of PHY in platform data of the
>>>>> controller? It should be deterministic as the PHY framework assigns
>>>>> its
>>>>> own id and we *don't* want to add any requirement that the ID must
>>>>> be
>>>>> assigned manually without using PLATFORM_DEVID_AUTO. We can get rid
>>>>> of
>>>>> *phy_init_data* in the v10 patch series.
>>
>> OK, so the PHY device name would have a fixed part, passed as
>> platform data of the controller and a variable part appended
>> by the PHY core, depending on the number of registered PHYs ?
>>
>> Then same PHY names would be passed as the PHY provider driver's
>> platform data ?
>>
>> Then if there are 2 instances of the above (same names in platform
>> data) how would be determined which PHY controller is linked to
>> which PHY supplier ?
>>
>> I guess you want each device instance to have different PHY device
>> names already in platform data ? That might work. We probably will
>> be focused mostly on DT anyway. It seem without DT we are trying
>> to find some layer that would allow us to couple relevant devices
>> and overcome driver core inconvenience that it provides to means
>> to identify specific devices in advance. :) Your proposal sounds
>> reasonable, however I might be missing some details or corner cases.
>>
>>>> What about slightly altering the concept of v9 to pass a pointer to
>>>> struct device instead of device name inside phy_init_data?
>>
>> As Felipe said, we don't want to pass pointers in platform_data
>> to/from random subsystems. We pass data, passing pointers would
>> be a total mess IMHO.
>
> Well, this is a total mess anyway... I don't really get the point of using
> PLATFORM_DEVID_AUTO. The only thing that comes to my mind is that you can
> use it if you don't care about the ID and so it can be assigned
> automatically.
>
> However my understanding of the device ID is that it was supposed to
> provide a way to identify multiple instances of identical devices in a
> reliable way, to solve problems like the one we are trying to solve
> here...
>
> So maybe let's stop solving an already solved problem and just state that
> you need to explicitly assign device ID to use this framework?
Felipe,
Can we have it the way I had in my v10 patch series till we find a better way?
I think this *non-dt* stuff shouldn't be blocking as most of the users are dt only?
Thanks
Kishon
^ permalink raw reply
* Changing which device has VTs?
From: Andy Lutomirski @ 2013-08-14 18:47 UTC (permalink / raw)
To: linux-fbdev
I have a box with a real graphics card (radeon) and an onboard
graphics card (mgag200). I want to use the radeon and ignore the
mgag200. For reasons of extreme firmware suckage, I have two choices:
1. Leave both devices enabled in BIOS and set the mgag200 device
primary. This causes efifb and later mgag200 to both point at the
mgag200. All of my text consoles end up on the mgag200. This is
unfortunate, especially because if, even if I set xorg to ignore the
mgag200 device, hitting ctrl-alt-f2 causes X to suspend itself and my
text console to show up on a device with no monitor attached.
2. Set the radeon device as primary in BIOS. System doesn't boot.
I'd like to leave mgag200 primary but tell Linux to put all the text
consoles on the radeon device once it shows up. I could compile out
both efifb and mgag200, but that seems like a waste. Is there any way
to do this with a command-line parameter? I tried fbcon=map:1, and I
get no fbcon at all.
--
Andy Lutomirski
AMA Capital Management, LLC
^ permalink raw reply
* Re: Changing which device has VTs?
From: Dave Airlie @ 2013-08-15 5:49 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <CALCETrX5_CAREEPSWkwE6+bY+w+c_qJcYBVM7Nx16_URZ9Gn5A@mail.gmail.com>
(resend, gmail went html again).
On Thu, Aug 15, 2013 at 4:47 AM, Andy Lutomirski <luto@amacapital.net> wrote:
> I have a box with a real graphics card (radeon) and an onboard
> graphics card (mgag200). I want to use the radeon and ignore the
> mgag200. For reasons of extreme firmware suckage, I have two choices:
>
> 1. Leave both devices enabled in BIOS and set the mgag200 device
> primary. This causes efifb and later mgag200 to both point at the
> mgag200. All of my text consoles end up on the mgag200. This is
> unfortunate, especially because if, even if I set xorg to ignore the
> mgag200 device, hitting ctrl-alt-f2 causes X to suspend itself and my
> text console to show up on a device with no monitor attached.
>
> 2. Set the radeon device as primary in BIOS. System doesn't boot.
get vendor to fix BIOS :-)
>
> I'd like to leave mgag200 primary but tell Linux to put all the text
> consoles on the radeon device once it shows up. I could compile out
> both efifb and mgag200, but that seems like a waste. Is there any way
> to do this with a command-line parameter? I tried fbcon=map:1, and I
> get no fbcon at all.
the mapping stuff should work, alternative is to write some code to
call the fbcon
event, FB_EVENT_REMAP_ALL_CONSOLE, which is what the GPU switcher
code uses to remap fbcon between switchable GPU systems.
Dave.
^ permalink raw reply
* Re: Changing which device has VTs?
From: Andy Lutomirski @ 2013-08-15 6:02 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <CALCETrX5_CAREEPSWkwE6+bY+w+c_qJcYBVM7Nx16_URZ9Gn5A@mail.gmail.com>
On Wed, Aug 14, 2013 at 10:49 PM, Dave Airlie <airlied@gmail.com> wrote:
> (resend, gmail went html again).
And gmail broke pgdn, too :(
>
> On Thu, Aug 15, 2013 at 4:47 AM, Andy Lutomirski <luto@amacapital.net> wrote:
>> I have a box with a real graphics card (radeon) and an onboard
>> graphics card (mgag200). I want to use the radeon and ignore the
>> mgag200. For reasons of extreme firmware suckage, I have two choices:
>>
>> 1. Leave both devices enabled in BIOS and set the mgag200 device
>> primary. This causes efifb and later mgag200 to both point at the
>> mgag200. All of my text consoles end up on the mgag200. This is
>> unfortunate, especially because if, even if I set xorg to ignore the
>> mgag200 device, hitting ctrl-alt-f2 causes X to suspend itself and my
>> text console to show up on a device with no monitor attached.
>>
>> 2. Set the radeon device as primary in BIOS. System doesn't boot.
>
> get vendor to fix BIOS :-)
Done :) (I'm now running some mysterious unreleased BIOS -- it's
vastly superior.)
>
>>
>> I'd like to leave mgag200 primary but tell Linux to put all the text
>> consoles on the radeon device once it shows up. I could compile out
>> both efifb and mgag200, but that seems like a waste. Is there any way
>> to do this with a command-line parameter? I tried fbcon=map:1, and I
>> get no fbcon at all.
>
> the mapping stuff should work, alternative is to write some code to
> call the fbcon
> event, FB_EVENT_REMAP_ALL_CONSOLE, which is what the GPU switcher
> code uses to remap fbcon between switchable GPU systems.
Blech. Fortunately, my new BIOS works and I can stop worrying.
(Plymouth is still broken -- separate bug filed.)
--Andy
>
> Dave.
--
Andy Lutomirski
AMA Capital Management, LLC
^ permalink raw reply
* [PATCH v3 0/5] ARM: vf610: Add DCU framebuffer driver for Vybrid VF610 platform
From: Alison Wang @ 2013-08-15 8:01 UTC (permalink / raw)
To: linux-arm-kernel
This series contain DCU framebuffer driver for Freescale Vybrid VF610 platform.
The Display Controller Unit (DCU) module is a system master that
fetches graphics stored in internal or external memory and displays
them on a TFT LCD panel. A wide range of panel sizes is supported
and the timing of the interface signals is highly configurable.
Graphics are read directly from memory and then blended in real-time,
which allows for dynamic content creation with minimal CPU intervention.
The features:
(1) Full RGB888 output to TFT LCD panel.
(2) For the current LCD panel, WQVGA "480x272" is tested.
(3) Blending of each pixel using up to 4 source layers dependent on size of panel.
(4) Each graphic layer can be placed with one pixel resolution in either axis.
(5) Each graphic layer support RGB565 and RGB888 direct colors without alpha channel
and BGRA8888 direct colors with an alpha channel.
(6) Each graphic layer support alpha blending with 8-bit resolution.
Changes in v3:
- Correct DCU_MODE_BLEND_ITER macro definition.
- Remove hardcode panel description in the driver. Use the videomode helpers to get the relevant data from devicetree.
- Correct the wrong indentation.
- Use dev_* for printing messages in drivers.
- Change calc_div_ratio() to fsl_dcu_calc_div(), and rewrite this function.
- Use devm_request_irq() instead of request_irq().
- Drop useless code.
- Increase the layers number to the maximum 6.
- Use dma_alloc_writecombine() instead of dma_alloc_coherent().
- Use runtime PM.
Changes in v2:
- Add a document for DCU framebuffer driver under Documentation/devicetree/bindings/fb/.
----------------------------------------------------------------
Alison Wang (5):
ARM: dts: vf610: Add DCU and TCON nodes
ARM: dts: vf610-twr: Enable DCU and TCON devices
ARM: clk: vf610: Add DCU and TCON clock support
fb: Add DCU framebuffer driver for Vybrid VF610 platform
Documentation: DT: Add DCU framebuffer driver
Documentation/devicetree/bindings/fb/fsl-dcu-fb.txt | 67 +++++
arch/arm/boot/dts/vf610-twr.dts | 32 +++
arch/arm/boot/dts/vf610.dtsi | 19 +-
arch/arm/mach-imx/clk-vf610.c | 5 +
drivers/video/Kconfig | 10 +
drivers/video/Makefile | 1 +
drivers/video/fsl-dcu-fb.c | 1095 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
include/dt-bindings/clock/vf610-clock.h | 3 +-
8 files changed, 1230 insertions(+), 2 deletions(-)
create mode 100644 Documentation/devicetree/bindings/fb/fsl-dcu-fb.txt
create mode 100644 drivers/video/fsl-dcu-fb.c
^ permalink raw reply
* [PATCH v3 1/5] ARM: dts: vf610: Add DCU and TCON nodes
From: Alison Wang @ 2013-08-15 8:01 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <1376553714-25922-1-git-send-email-b18965@freescale.com>
This patch adds DCU and TCON nodes in SoC level DTS for Freescale Vybrid VF610.
It also removes useless pin for DCU0 pinctrl.
Signed-off-by: Alison Wang <b18965@freescale.com>
---
Changes in v3: None
Changes in v2: None
arch/arm/boot/dts/vf610.dtsi | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/vf610.dtsi b/arch/arm/boot/dts/vf610.dtsi
index 67d929c..145e1f4 100644
--- a/arch/arm/boot/dts/vf610.dtsi
+++ b/arch/arm/boot/dts/vf610.dtsi
@@ -140,6 +140,14 @@
clock-names = "pit";
};
+ tcon0: tcon@4003d000 {
+ compatible = "fsl,vf610-tcon";
+ reg = <0x4003d000 0x1000>;
+ clocks = <&clks VF610_CLK_TCON0>;
+ clock-names = "tcon";
+ status = "disabled";
+ };
+
wdog@4003e000 {
compatible = "fsl,vf610-wdt", "fsl,imx21-wdt";
reg = <0x4003e000 0x1000>;
@@ -169,7 +177,6 @@
dcu0 {
pinctrl_dcu0_1: dcu0grp_1 {
fsl,pins = <
- VF610_PAD_PTB8__GPIO_30 0x42
VF610_PAD_PTE0__DCU0_HSYNC 0x42
VF610_PAD_PTE1__DCU0_VSYNC 0x42
VF610_PAD_PTE2__DCU0_PCLK 0x42
@@ -395,6 +402,16 @@
reg = <0x40050000 0x1000>;
};
+ dcu0: dcu@40058000 {
+ compatible = "fsl,vf610-dcu";
+ reg = <0x40058000 0x1200>;
+ interrupts = <0 30 0x04>;
+ clocks = <&clks VF610_CLK_DCU0>;
+ clock-names = "dcu";
+ tcon-controller = <&tcon0>;
+ status = "disabled";
+ };
+
i2c0: i2c@40066000 {
#address-cells = <1>;
#size-cells = <0>;
--
1.8.0
^ permalink raw reply related
* [PATCH v3 2/5] ARM: dts: vf610-twr: Enable DCU and TCON devices
From: Alison Wang @ 2013-08-15 8:01 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <1376553714-25922-1-git-send-email-b18965@freescale.com>
This patch enables DCU and TCON devices for Vybrid VF610 TOWER board.
Signed-off-by: Alison Wang <b18965@freescale.com>
---
Changes in v3: Add panel description in devicetree.
Changes in v2: None
arch/arm/boot/dts/vf610-twr.dts | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/arch/arm/boot/dts/vf610-twr.dts b/arch/arm/boot/dts/vf610-twr.dts
index b3905f5..82c03fe 100644
--- a/arch/arm/boot/dts/vf610-twr.dts
+++ b/arch/arm/boot/dts/vf610-twr.dts
@@ -36,6 +36,34 @@
};
+&dcu0 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_dcu0_1>;
+ display = <&display>;
+ status = "okay";
+
+ display: display@0 {
+ bits-per-pixel = <24>;
+
+ display-timings {
+ native-mode = <&timing0>;
+ timing0: nl4827hc19 {
+ clock-frequency = <10870000>;
+ hactive = <480>;
+ vactive = <272>;
+ hback-porch = <2>;
+ hfront-porch = <2>;
+ vback-porch = <1>;
+ vfront-porch = <1>;
+ hsync-len = <41>;
+ vsync-len = <2>;
+ hsync-active = <1>;
+ vsync-active = <1>;
+ };
+ };
+ };
+};
+
&fec0 {
phy-mode = "rmii";
pinctrl-names = "default";
@@ -50,6 +78,10 @@
status = "okay";
};
+&tcon0 {
+ status = "okay";
+};
+
&uart1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart1_1>;
--
1.8.0
^ permalink raw reply related
* [PATCH v3 3/5] ARM: clk: vf610: Add DCU and TCON clock support
From: Alison Wang @ 2013-08-15 8:01 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <1376553714-25922-1-git-send-email-b18965@freescale.com>
This patch adds DCU and TCON clock support for Vybrid VF610 platform.
Signed-off-by: Alison Wang <b18965@freescale.com>
---
Changes in v3: None
Changes in v2: None
arch/arm/mach-imx/clk-vf610.c | 5 +++++
include/dt-bindings/clock/vf610-clock.h | 3 ++-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mach-imx/clk-vf610.c b/arch/arm/mach-imx/clk-vf610.c
index b169a39..689d3da 100644
--- a/arch/arm/mach-imx/clk-vf610.c
+++ b/arch/arm/mach-imx/clk-vf610.c
@@ -247,6 +247,8 @@ static void __init vf610_clocks_init(struct device_node *ccm_node)
clk[VF610_CLK_DCU1_DIV] = imx_clk_divider("dcu1_div", "dcu1_en", CCM_CSCDR3, 20, 3);
clk[VF610_CLK_DCU1] = imx_clk_gate2("dcu1", "dcu1_div", CCM_CCGR9, CCM_CCGRx_CGn(8));
+ clk[VF610_CLK_TCON0] = imx_clk_gate2("tcon0", "platform_bus", CCM_CCGR1, CCM_CCGRx_CGn(13));
+
clk[VF610_CLK_ESAI_SEL] = imx_clk_mux("esai_sel", CCM_CSCMR1, 20, 2, esai_sels, 4);
clk[VF610_CLK_ESAI_EN] = imx_clk_gate("esai_en", "esai_sel", CCM_CSCDR2, 30);
clk[VF610_CLK_ESAI_DIV] = imx_clk_divider("esai_div", "esai_en", CCM_CSCDR2, 24, 4);
@@ -313,6 +315,9 @@ static void __init vf610_clocks_init(struct device_node *ccm_node)
clk_set_parent(clk[VF610_CLK_SAI2_SEL], clk[VF610_CLK_AUDIO_EXT]);
clk_set_parent(clk[VF610_CLK_SAI3_SEL], clk[VF610_CLK_AUDIO_EXT]);
+ clk_set_parent(clk[VF610_CLK_DCU0_SEL], clk[VF610_CLK_PLL1_PFD2]);
+ clk_set_rate(clk[VF610_CLK_DCU0_DIV], 113200000);
+
/* Add the clocks to provider list */
clk_data.clks = clk;
clk_data.clk_num = ARRAY_SIZE(clk);
diff --git a/include/dt-bindings/clock/vf610-clock.h b/include/dt-bindings/clock/vf610-clock.h
index 4aa2b48..4ccf563 100644
--- a/include/dt-bindings/clock/vf610-clock.h
+++ b/include/dt-bindings/clock/vf610-clock.h
@@ -160,6 +160,7 @@
#define VF610_CLK_GPU2D 147
#define VF610_CLK_ENET0 148
#define VF610_CLK_ENET1 149
-#define VF610_CLK_END 150
+#define VF610_CLK_TCON0 150
+#define VF610_CLK_END 151
#endif /* __DT_BINDINGS_CLOCK_VF610_H */
--
1.8.0
^ permalink raw reply related
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