* 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: [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
* [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
* [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
* 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
* 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 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: [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
* [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: [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
* 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 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
* [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
* [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
* [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
* 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
* 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
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^ permalink raw reply
* 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
* [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: [RFC 0/1] Adding DT support to video/da8xx-fb.c
From: Darren Etheridge @ 2013-08-12 19:11 UTC (permalink / raw)
To: Tomi Valkeinen; +Cc: devicetree, plagnioj, linux-fbdev, afzal
In-Reply-To: <52052D10.7060803@ti.com>
Tomi Valkeinen <tomi.valkeinen@ti.com> wrote on Fri [2013-Aug-09 20:55:28 +0300]:
> Hi,
>
> On 08/08/13 23:15, Darren Etheridge wrote:
> > This is part of a larger series of patches to upgrade the da8xx-fb.c driver
> > to support the Texas Instruments AM335x device. As part of this upgrade
> > we also want to add devicetree support for both the original da8xx and the
> > am335x. Tomi Valkeinen has reviewed the fbdev changes but he suggested
> > that it was prudent to extract the dt pieces and run it through the
> > devicetree mailing list for review.
> >
> > Thanks,
> > Darren
> >
> > Darren Etheridge (1):
> > video: da8xx-fb: adding dt support
> >
> > .../devicetree/bindings/video/fb-da8xx.txt | 37 +++++++++++
> > drivers/video/da8xx-fb.c | 67 +++++++++++++++++++-
> > 2 files changed, 101 insertions(+), 3 deletions(-)
> > create mode 100644 Documentation/devicetree/bindings/video/fb-da8xx.txt
>
> I just realized something. We have both drm and fb drivers for the LCDC
> IP. The hardware is the same, thus, there should only be one set of DT
> bindings, used by both drivers.
>
> I don't know why this didn't occur to me earlier, as it's the same
> situation with OMAP DSS.
>
OK that makes sense. So in this case what I need to do is change the
.compatible to match the gpu/drm/driver/tilcdc driver which has the
existing binding so it would become ti,am33xx-tilcdc instead of
ti,am3352-lcdc. This fbdev driver also supports da8xx class devices
so I would just rename this second .compatible to be ti,da8xx-tilcdc
to be consistent with the other. The fbdev driver doesn't support
some of the options that the tilcdc/drm driver supports, but that
shouldn't be a problem for the fbdev driver.
I will also change the name of the documentation file to be
da8xx-fb.txt to match the driver name.
Darren
^ permalink raw reply
* Re: [V4 1/5] video: mmp: rb swap setting update for mmp display
From: jett zhou @ 2013-08-12 11:25 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <1375077384-7467-1-git-send-email-jtzhou@marvell.com>
Hi Jean
Would you please help to review these 5 patches when you have
time, thanks very much.
Thanks
2013/7/29 Jett.Zhou <jtzhou@marvell.com>:
> From: Guoqing Li <ligq@marvell.com>
>
> We could set rb swap in two modules: DMA controler input part and
> dsi interface output part.
> DMA input part is based on pix_fmt to set rbswap, dsi output interface
> part will set rbswap based on platform dsi_rbswap configuration.
>
> This patch include below change and enhancement:
>
> 1) The input format which support rbswap is based on RGB format,
> eg. RGB565 indicates the source data in memory is that Red is [15~11],
> Green is [10~5], Blue is [4:0], Red is MSB, Blue is LSB, but for the
> display dma input default setting(rbswap = 0), it only support Blue
> is [15~11], Green is [10~5], Red is [4:0], Red is LSB, Blue is MSB,
> so for this format(RGB565), display controller need to set rbswap
> = 1 and it can support the MSB/LSB correctly.
> BGR/YUV format will not set it in mmp display driver.
>
> 2) The dsi output part of rbswap is depend on dsi_rbswap which is
> defined in specific platfrom. For output dsi interface, it has this
> feature to do rbswap again if it needs specifc byte sequence of RGB
> byte for DSI panel.
> eg. If display content is set RGB565 in memory and DMA input part set
> rbswap in driver to support Red as MSB , Blue LSB, but dsi panel only
> support Red as LSB, Blue as MSB, then it can use this feature.
> If there is no this requirement of panel, this dsi output part is not
> needed.
>
> Signed-off-by: Guoqing Li <ligq@marvell.com>
> Signed-off-by: Jett.Zhou <jtzhou@marvell.com>
> Reviewed-by: Daniel Drake <dsd@laptop.org>
> ---
> drivers/video/mmp/hw/mmp_ctrl.c | 19 +++++++++++--------
> drivers/video/mmp/hw/mmp_ctrl.h | 5 +++++
> include/video/mmp_disp.h | 1 +
> 3 files changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/video/mmp/hw/mmp_ctrl.c b/drivers/video/mmp/hw/mmp_ctrl.c
> index 75dca19..a40d95a 100644
> --- a/drivers/video/mmp/hw/mmp_ctrl.c
> +++ b/drivers/video/mmp/hw/mmp_ctrl.c
> @@ -60,8 +60,7 @@ static irqreturn_t ctrl_handle_irq(int irq, void *dev_id)
>
> static u32 fmt_to_reg(struct mmp_overlay *overlay, int pix_fmt)
> {
> - u32 link_config = path_to_path_plat(overlay->path)->link_config;
> - u32 rbswap, uvswap = 0, yuvswap = 0,
> + u32 rbswap = 0, uvswap = 0, yuvswap = 0,
> csc_en = 0, val = 0,
> vid = overlay_is_vid(overlay);
>
> @@ -71,27 +70,23 @@ static u32 fmt_to_reg(struct mmp_overlay *overlay, int pix_fmt)
> case PIXFMT_RGB888PACK:
> case PIXFMT_RGB888UNPACK:
> case PIXFMT_RGBA888:
> - rbswap = !(link_config & 0x1);
> + rbswap = 1;
> break;
> case PIXFMT_VYUY:
> case PIXFMT_YVU422P:
> case PIXFMT_YVU420P:
> - rbswap = link_config & 0x1;
> uvswap = 1;
> break;
> case PIXFMT_YUYV:
> - rbswap = link_config & 0x1;
> yuvswap = 1;
> break;
> default:
> - rbswap = link_config & 0x1;
> break;
> }
>
> switch (pix_fmt) {
> case PIXFMT_RGB565:
> case PIXFMT_BGR565:
> - val = 0;
> break;
> case PIXFMT_RGB1555:
> case PIXFMT_BGR1555:
> @@ -248,7 +243,8 @@ static void path_set_mode(struct mmp_path *path, struct mmp_mode *mode)
> {
> struct lcd_regs *regs = path_regs(path);
> u32 total_x, total_y, vsync_ctrl, tmp, sclk_src, sclk_div,
> - link_config = path_to_path_plat(path)->link_config;
> + link_config = path_to_path_plat(path)->link_config,
> + dsi_rbswap = path_to_path_plat(path)->link_config;
>
> /* FIXME: assert videomode supported */
> memcpy(&path->mode, mode, sizeof(struct mmp_mode));
> @@ -263,6 +259,12 @@ static void path_set_mode(struct mmp_path *path, struct mmp_mode *mode)
> tmp |= CFG_DUMB_ENA(1);
> writel_relaxed(tmp, ctrl_regs(path) + intf_ctrl(path->id));
>
> + /* interface rb_swap setting */
> + tmp = readl_relaxed(ctrl_regs(path) + intf_rbswap_ctrl(path->id)) &
> + (~(CFG_INTFRBSWAP_MASK));
> + tmp |= dsi_rbswap & CFG_INTFRBSWAP_MASK;
> + writel_relaxed(tmp, ctrl_regs(path) + intf_rbswap_ctrl(path->id));
> +
> writel_relaxed((mode->yres << 16) | mode->xres, ®s->screen_active);
> writel_relaxed((mode->left_margin << 16) | mode->right_margin,
> ®s->screen_h_porch);
> @@ -419,6 +421,7 @@ static int path_init(struct mmphw_path_plat *path_plat,
> path_plat->path = path;
> path_plat->path_config = config->path_config;
> path_plat->link_config = config->link_config;
> + path_plat->dsi_rbswap = config->dsi_rbswap;
> path_set_default(path);
>
> kfree(path_info);
> diff --git a/drivers/video/mmp/hw/mmp_ctrl.h b/drivers/video/mmp/hw/mmp_ctrl.h
> index edd2002..53301cf 100644
> --- a/drivers/video/mmp/hw/mmp_ctrl.h
> +++ b/drivers/video/mmp/hw/mmp_ctrl.h
> @@ -163,6 +163,8 @@ struct lcd_regs {
>
> #define LCD_SCLK(path) ((PATH_PN = path->id) ? LCD_CFG_SCLK_DIV :\
> ((PATH_TV = path->id) ? LCD_TCLK_DIV : LCD_PN2_SCLK_DIV))
> +#define intf_rbswap_ctrl(id) ((id) ? (((id) & 1) ? LCD_TVIF_CTRL : \
> + PN2_IOPAD_CONTROL) : LCD_TOP_CTRL)
>
> /* dither configure */
> #ifdef CONFIG_CPU_PXA988
> @@ -615,6 +617,8 @@ struct lcd_regs {
> #define LCD_SPU_DUMB_CTRL 0x01B8
> #define CFG_DUMBMODE(mode) ((mode)<<28)
> #define CFG_DUMBMODE_MASK 0xF0000000
> +#define CFG_INTFRBSWAP(mode) ((mode)<<24)
> +#define CFG_INTFRBSWAP_MASK 0x0F000000
> #define CFG_LCDGPIO_O(data) ((data)<<20)
> #define CFG_LCDGPIO_O_MASK 0x0FF00000
> #define CFG_LCDGPIO_ENA(gpio) ((gpio)<<12)
> @@ -1427,6 +1431,7 @@ struct mmphw_path_plat {
> struct mmp_path *path;
> u32 path_config;
> u32 link_config;
> + u32 dsi_rbswap;
> };
>
> /* mmp ctrl describes mmp controller related info */
> diff --git a/include/video/mmp_disp.h b/include/video/mmp_disp.h
> index b9dd1fb..32094c0 100644
> --- a/include/video/mmp_disp.h
> +++ b/include/video/mmp_disp.h
> @@ -334,6 +334,7 @@ struct mmp_mach_path_config {
> int output_type;
> u32 path_config;
> u32 link_config;
> + u32 dsi_rbswap;
> };
>
> struct mmp_mach_plat_info {
> --
> 1.7.0.4
>
--
----------------------------------
Best Regards
Jett Zhou
^ permalink raw reply
* About buffer sychronization mechanism and cache operation
From: Inki Dae @ 2013-08-12 9:55 UTC (permalink / raw)
To: linux-fbdev
Hello all,
The purpose of this email is to get other opinions and advices to buffer synchronization mechanism, and coupling cache operation feature with the buffer synchronization mechanism. First of all, I am not a native English speaker so I'm not sure that I can convey my intention to you. And I'm not a specialist in Linux than other people so also there might be my missing points.
I had posted the buffer synchronization mechanism called dmabuf sync framework like below,
http://lists.infradead.org/pipermail/linux-arm-kernel/2013-June/177045.html
And I'm sending this email before posting next version with more stable patch set and features. 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.
There are two cases we are using this buffer synchronization framework. One is to primarily enhance GPU rendering performance on Tizen platform in case of 3d app with compositing mode that the 3d app draws something in off-screen buffer.
And other is to couple buffer access control and cache operation between CPU and DMA; the cache operation is done by the dmabuf sync framework in kernel side.
Why do we need buffer access control between CPU and DMA?
---------------------------------------------------------
The below shows simple 3D software layers,
3D Application
-----------------------------------------
Standard OpenGL ES and EGL Interfaces ------- [A]
-----------------------------------------
MALI OpenGL ES and EGL Native modules --------- [B]
-----------------------------------------
Exynos DRM Driver | GPU Driver ---------- [C]
3d application requests 3d rendering through A. And then B fills a 3d command buffer with the requests from A. And then 3D application calls glFlush so that the 3d command buffer can be submitted to C, and rendered by GPU hardware. Internally, glFlush(also glFinish) will call a function of native module[B] glFinish blocks caller's task until all GL execution is complete. On the other hand, glFlush forces execution of GL commands but doesn't block the caller's task until the completion.
In composting mode, in case of using glFinish, the 3d rendering performance is quite lower than using glFlush because glFinish makes CPU blocked until the execution of the 3d commands is completed. However, the use of glFlush has one issue that the shared buffer with GPU could be broken when CPU accesses the shared buffer at once after glFlush because CPU cannot be aware of the completion of GPU access to the shared buffer: actually, Tizen platform internally calls only eglSwapBuffer instead of glFlush and glFinish, and whether flushing or finishing is decided according to compositing mode or not. So in such case, we would need buffer access control between CPU and DMA for more performance.
About cache operation
---------------------
The dmabuf sync framework can include cache operation feature, and the below shows how the cache operation based on dmabuf sync framework is performed,
device driver in kernel or fctrl in user land
dmabuf_sync_lock or dmabuf_sync_single_lock
check before and after buffer access
dma_buf_begin_cpu_access or dma_buf_end_cpu_access
begin_cpu_access or end_cpu_access of exporter
dma_sync_sg_for_device or dma_sync_sg_for_cpu
In case that using dmabuf sync framework, kernel can be aware of when CPU and DMA access to a shared buffer is completed so we can do cache operation in kernel so that way, we can couple buffer access control and cache operation. So with this, we can avoid that user land overuses cache operation.
I guess most Linux based platforms are using cachable mapped buffer for more performance: in case that CPU frequently accesses the shared buffer which is shared with DMA, the use of cachable mapped buffer is more fast than the use of non-cachable. However, this way could make cache operation overused by user land because only user land can be aware of the completion of CPU or DMA access to the shared buffer so user land could request cache operations every time it wants even the cache operation is unnecessary. That is how user land could overuse cache operations.
To Android, Chrome OS, and other forks,
Are there other cases that buffer access control between CPU and DMA is needed? I know Android sync driver and KDS are already being used for Android, Chrome OS, and so on.
How does your platform do cache operation? And How do you think about coupling buffer access control and cache operation between CPU and DMA?.
Lastly, I think we may need Linux generic buffer synchronization mechanism that uses only Linux standard interfaces (dmabuf) including user land interfaces (fcntl and select system calls), and the dmabuf sync framework could meet it.
Thanks,
Inki Dae
^ permalink raw reply
* Re: EDID modes unavailable when no connector/crtc available at boot
From: Dave Airlie @ 2013-08-11 10:06 UTC (permalink / raw)
To: Tony Prisk; +Cc: linux-fbdev@vger.kernel.org, dri-devel
In-Reply-To: <52075C9E.6040901@prisktech.co.nz>
On Sun, Aug 11, 2013 at 7:42 PM, Tony Prisk <linux@prisktech.co.nz> wrote:
> On 11/08/13 20:42, Dave Airlie wrote:
>>
>> On Sun, Aug 11, 2013 at 2:41 PM, Tony Prisk <linux@prisktech.co.nz> wrote:
>>>
>>> I am working on the HDMI driver for the i.MX6 as part of the larger DRM
>>> driver written by Sascha Hauer and need a little advice. I seem to be
>>> missing one important part of the subsystem that I haven't been able to
>>> resolve.
>>>
>> fbcon is limited by boot sizes as at least with dynamic memory
>> management and how fbdev works resizing the allocation is nearly
>> impossible to do race free, since fbdev will hand out mmaps to
>> userspace and that stops you from ever moving anything once the device
>> is open.
>>
>> But this is only for the fbdev emulation, a real kms application
>> should be able to use a larger size no problems.
>>
>> Dave.
>
> It seems to be worse than just a fbcon issue as far as I can tell.
>
> I am making an assumption, but I believe
> '/sys/class/drm/card0-HDMI-A-1/modes' should list all the supported modes of
> the connector (regardless of fbcon).
> Using 'cat /sys/class/drm/card0-HDMI-A-1/modes', it appears the supported
> modes are being limited by fbcon
>
> 1) HDMI Cable connected at bootup (fb @ 1920x1080)
> cat /sys/class/drm/card0-HDMI-A-1/modes
> 1920x1080
> 1280x720
> 1280x720
> 720x576
> 720x480
> 640x480
>
> 2) HDMI Cable NOT connected at bootup (fb @ 1024x768), cable is then
> connected after userspace has started (still in console)
> cat /sys/class/drm/card0-HDMI-A-1/modes
> 720x576
> 720x480
> 640x480
>
>
> Following back through the source:
>
> static struct drm_connector_funcs imx_hdmi_connector_funcs = {
> .fill_modes = drm_helper_probe_single_connector_modes,
> ...
> };
>
> static struct drm_connector_helper_funcs imx_hdmi_connector_helper_funcs = {
> .get_modes = imx_hdmi_connector_get_modes,
> .mode_valid = imx_hdmi_connector_mode_valid,
> ...
> };
>
>
> It appears that only drm_helper_probe_single_connector_modes() calls
> .get_modes() and .mode_valid()
> .fill_modes() is called from drm_fb_helper_probe_connector_modes(), which is
> called from drm_fb_helper_hotplug_event()
> drm_fb_helper_hotplug_event() sets max_width to fb_helper->fb->width, and
> max_height to fb_helper->fb->height.
> fb->width is 1024 if booted without the cable connected, hence the clipping
> of the values.
fill_modes is also called from the drm_crtc.c userspace interface, all
the functions in drm_fb_helper are for fbdev/con use, the fact sysfs
is wrong is only a side effect.
Userspace should get a full list of modes, try using the modetest
application which I think should work.
Dave.
^ permalink raw reply
* Re: EDID modes unavailable when no connector/crtc available at boot
From: Tony Prisk @ 2013-08-11 9:42 UTC (permalink / raw)
To: Dave Airlie; +Cc: linux-fbdev@vger.kernel.org, dri-devel
In-Reply-To: <CAPM=9tzShWxZ-f=641r+-uc21JkY3kTeM2K=tsiB+OotNCnrQA@mail.gmail.com>
On 11/08/13 20:42, Dave Airlie wrote:
> On Sun, Aug 11, 2013 at 2:41 PM, Tony Prisk <linux@prisktech.co.nz> wrote:
>> I am working on the HDMI driver for the i.MX6 as part of the larger DRM
>> driver written by Sascha Hauer and need a little advice. I seem to be
>> missing one important part of the subsystem that I haven't been able to
>> resolve.
>>
> fbcon is limited by boot sizes as at least with dynamic memory
> management and how fbdev works resizing the allocation is nearly
> impossible to do race free, since fbdev will hand out mmaps to
> userspace and that stops you from ever moving anything once the device
> is open.
>
> But this is only for the fbdev emulation, a real kms application
> should be able to use a larger size no problems.
>
> Dave.
It seems to be worse than just a fbcon issue as far as I can tell.
I am making an assumption, but I believe
'/sys/class/drm/card0-HDMI-A-1/modes' should list all the supported
modes of the connector (regardless of fbcon).
Using 'cat /sys/class/drm/card0-HDMI-A-1/modes', it appears the
supported modes are being limited by fbcon
1) HDMI Cable connected at bootup (fb @ 1920x1080)
cat /sys/class/drm/card0-HDMI-A-1/modes
1920x1080
1280x720
1280x720
720x576
720x480
640x480
2) HDMI Cable NOT connected at bootup (fb @ 1024x768), cable is then
connected after userspace has started (still in console)
cat /sys/class/drm/card0-HDMI-A-1/modes
720x576
720x480
640x480
Following back through the source:
static struct drm_connector_funcs imx_hdmi_connector_funcs = {
.fill_modes = drm_helper_probe_single_connector_modes,
...
};
static struct drm_connector_helper_funcs imx_hdmi_connector_helper_funcs = {
.get_modes = imx_hdmi_connector_get_modes,
.mode_valid = imx_hdmi_connector_mode_valid,
...
};
It appears that only drm_helper_probe_single_connector_modes() calls
.get_modes() and .mode_valid()
.fill_modes() is called from drm_fb_helper_probe_connector_modes(),
which is called from drm_fb_helper_hotplug_event()
drm_fb_helper_hotplug_event() sets max_width to fb_helper->fb->width,
and max_height to fb_helper->fb->height.
fb->width is 1024 if booted without the cable connected, hence the
clipping of the values.
Regards
Tony Prisk
^ permalink raw reply
* Re: EDID modes unavailable when no connector/crtc available at boot
From: Dave Airlie @ 2013-08-11 8:42 UTC (permalink / raw)
To: Tony Prisk; +Cc: linux-fbdev@vger.kernel.org, dri-devel
In-Reply-To: <5207160A.6070803@prisktech.co.nz>
On Sun, Aug 11, 2013 at 2:41 PM, Tony Prisk <linux@prisktech.co.nz> wrote:
> I am working on the HDMI driver for the i.MX6 as part of the larger DRM
> driver written by Sascha Hauer and need a little advice. I seem to be
> missing one important part of the subsystem that I haven't been able to
> resolve.
>
fbcon is limited by boot sizes as at least with dynamic memory
management and how fbdev works resizing the allocation is nearly
impossible to do race free, since fbdev will hand out mmaps to
userspace and that stops you from ever moving anything once the device
is open.
But this is only for the fbdev emulation, a real kms application
should be able to use a larger size no problems.
Dave.
^ permalink raw reply
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