[PATCH v4 1/2] libcamera: Extend u32 control type

Cheng-Hao Yang chenghaoyang at chromium.org
Tue Oct 29 11:08:44 CET 2024


Hi Jacopo,

On Mon, Oct 28, 2024 at 6:36 PM Jacopo Mondi
<jacopo.mondi at ideasonboard.com> wrote:
>
> Hi Harvey
>
> On Fri, Oct 25, 2024 at 03:38:50PM +0000, Harvey Yang wrote:
> > From: Yudhistira Erlandinata <yerlandinata at chromium.org>
> >
> > V4L2 Controls support a wide variety of types not yet supported by the
> > ControlValue type system.
> >
> > Extend the libcamera ControlValue types to support an explicit 32 bit
> > unsigned integer type, and map that to the corresponding
> > V4L2_CTRL_TYPE_U32 type within the v4l2_device support class.
> >
> > Signed-off-by: Yudhistira Erlandinata <yerlandinata at chromium.org>
> > Co-developed-by: Harvey Yang <chenghaoyang at chromium.org>
> > Signed-off-by: Harvey Yang <chenghaoyang at chromium.org>
> > ---
> >  include/libcamera/controls.h    |  7 ++++++
> >  src/libcamera/controls.cpp      | 12 ++++++++--
> >  src/libcamera/v4l2_device.cpp   | 14 ++++++++++++
> >  test/controls/control_value.cpp | 40 +++++++++++++++++++++++++++++++++
> >  4 files changed, 71 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h
> > index ca60bbaca..6da8ad2c3 100644
> > --- a/include/libcamera/controls.h
> > +++ b/include/libcamera/controls.h
> > @@ -29,6 +29,7 @@ enum ControlType {
> >       ControlTypeNone,
> >       ControlTypeBool,
> >       ControlTypeByte,
> > +     ControlTypeUnsigned32,
> >       ControlTypeInteger32,
> >       ControlTypeInteger64,
> >       ControlTypeFloat,
> > @@ -62,6 +63,12 @@ struct control_type<uint8_t> {
> >       static constexpr std::size_t size = 0;
> >  };
> >
> > +template<>
> > +struct control_type<uint32_t> {
> > +     static constexpr ControlType value = ControlTypeUnsigned32;
> > +     static constexpr std::size_t size = 0;
> > +};
> > +
> >  template<>
> >  struct control_type<int32_t> {
> >       static constexpr ControlType value = ControlTypeInteger32;
> > diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
> > index 62185d643..8ae295191 100644
> > --- a/src/libcamera/controls.cpp
> > +++ b/src/libcamera/controls.cpp
> > @@ -54,6 +54,7 @@ static constexpr size_t ControlValueSize[] = {
> >       [ControlTypeNone]               = 0,
> >       [ControlTypeBool]               = sizeof(bool),
> >       [ControlTypeByte]               = sizeof(uint8_t),
> > +     [ControlTypeUnsigned32]         = sizeof(uint32_t),
> >       [ControlTypeInteger32]          = sizeof(int32_t),
> >       [ControlTypeInteger64]          = sizeof(int64_t),
> >       [ControlTypeFloat]              = sizeof(float),
> > @@ -74,10 +75,12 @@ static constexpr size_t ControlValueSize[] = {
> >   * The control stores a boolean value
> >   * \var ControlTypeByte
> >   * The control stores a byte value as an unsigned 8-bit integer
> > + * \var ControlTypeUnsigned32
> > + * The control stores an unsigned 32-bit integer value
> >   * \var ControlTypeInteger32
> > - * The control stores a 32-bit integer value
> > + * The control stores a signed 32-bit integer value
> >   * \var ControlTypeInteger64
> > - * The control stores a 64-bit integer value
> > + * The control stores a signed 64-bit integer value
> >   * \var ControlTypeFloat
> >   * The control stores a 32-bit floating point value
> >   * \var ControlTypeString
> > @@ -230,6 +233,11 @@ std::string ControlValue::toString() const
> >                       str += std::to_string(*value);
> >                       break;
> >               }
> > +             case ControlTypeUnsigned32: {
> > +                     const uint32_t *value = reinterpret_cast<const uint32_t *>(data);
> > +                     str += std::to_string(*value);
> > +                     break;
> > +             }
> >               case ControlTypeInteger32: {
> >                       const int32_t *value = reinterpret_cast<const int32_t *>(data);
> >                       str += std::to_string(*value);
> > diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> > index 68add4f2e..f39ec3760 100644
> > --- a/src/libcamera/v4l2_device.cpp
> > +++ b/src/libcamera/v4l2_device.cpp
> > @@ -9,6 +9,7 @@
> >
> >  #include <fcntl.h>
> >  #include <map>
> > +#include <stdint.h>
> >  #include <stdlib.h>
> >  #include <string.h>
> >  #include <sys/ioctl.h>
> > @@ -210,6 +211,10 @@ ControlList V4L2Device::getControls(const std::vector<uint32_t> &ids)
> >                               type = ControlTypeByte;
> >                               break;
> >
> > +                     case V4L2_CTRL_TYPE_U32:
> > +                             type = ControlTypeUnsigned32;
> > +                             break;
> > +
>
> This is not enough.
>
> After the switch we have
>
>                         ControlValue &value = ctrl.second;
>                         value.reserve(type, true, info.elems);
>                         Span<uint8_t> data = value.data();
>
>                         v4l2Ctrl.p_u8 = data.data();
>                         v4l2Ctrl.size = data.size();
>
> However controls of type V4L2_CTRL_TYPE_U32 use the p_u32 union member
> of 'struct v4l2_ext_control'
> https://www.kernel.org/doc/html/v4.9/media/uapi/v4l/vidioc-g-ext-ctrls.html#id1
>
> Same for U16 control types.
>
> Be careful about one thing. v4l2Ctrl.p_u32 is of type __u32* so it
> would feel natural to
>
>                         Span<uint32_t> data = value.data();
>                         v4l2Ctrl.p_u32 = data.data();
>
> as data.data() returns a T*
>
> However v4l2Ctrl.size wants the size in bytes while data.size()
> returns the number of elements, so you should probably use
> data.size_bytes().
>
> Or you can do as we do in setControls and cast the data.data()
> pointer.
>
>                         Span<uint8_t> data = value.data();
>                         v4l2Ctrl.p_u32 = reinterpret_cast<uint32_t *>(data.data());
>                         v4l2Ctrl.size = data.size();
>
> Also, you need to handle U32 and U16 also setControl().

Thanks for the catch!
Please help take a look at my WIP patch:
https://gitlab.freedesktop.org/chenghaoyang/libcamera/-/commit/faec47f605881062e58718371183a0c2d3ffe772
, before I upload another version.
Let me know if you think I should merge the two `switch`es and duplicate
the code in the middle.

>
> If you can test this by reading and writing u16 and u32 controls this
> would make me way more confident this patch is correct.

Hmm, I couldn't find such a use case. Can you suggest how we could
test it?

BR,
Harvey

>
> Thanks
>    j
>
> >                       default:
> >                               LOG(V4L2, Error)
> >                                       << "Unsupported payload control type "
> > @@ -488,6 +493,9 @@ ControlType V4L2Device::v4l2CtrlType(uint32_t ctrlType)
> >       case V4L2_CTRL_TYPE_BOOLEAN:
> >               return ControlTypeBool;
> >
> > +     case V4L2_CTRL_TYPE_U32:
> > +             return ControlTypeUnsigned32;
> > +
> >       case V4L2_CTRL_TYPE_INTEGER:
> >               return ControlTypeInteger32;
> >
> > @@ -536,6 +544,11 @@ std::optional<ControlInfo> V4L2Device::v4l2ControlInfo(const v4l2_query_ext_ctrl
> >                                  static_cast<uint8_t>(ctrl.maximum),
> >                                  static_cast<uint8_t>(ctrl.default_value));
> >
> > +     case V4L2_CTRL_TYPE_U32:
> > +             return ControlInfo(static_cast<uint32_t>(ctrl.minimum),
> > +                                static_cast<uint32_t>(ctrl.maximum),
> > +                                static_cast<uint32_t>(ctrl.default_value));
> > +
> >       case V4L2_CTRL_TYPE_BOOLEAN:
> >               return ControlInfo(static_cast<bool>(ctrl.minimum),
> >                                  static_cast<bool>(ctrl.maximum),
> > @@ -622,6 +635,7 @@ void V4L2Device::listControls()
> >               case V4L2_CTRL_TYPE_BITMASK:
> >               case V4L2_CTRL_TYPE_INTEGER_MENU:
> >               case V4L2_CTRL_TYPE_U8:
> > +             case V4L2_CTRL_TYPE_U32:
> >                       break;
> >               /* \todo Support other control types. */
> >               default:
> > diff --git a/test/controls/control_value.cpp b/test/controls/control_value.cpp
> > index 344107fae..6ca85b739 100644
> > --- a/test/controls/control_value.cpp
> > +++ b/test/controls/control_value.cpp
> > @@ -109,6 +109,46 @@ protected:
> >                       return TestFail;
> >               }
> >
> > +             /*
> > +              * Unsigned Integer32 type.
> > +              */
> > +             value.set(static_cast<uint32_t>(42));
> > +             if (value.isNone() || value.isArray() ||
> > +                 value.type() != ControlTypeUnsigned32) {
> > +                     cerr << "Control type mismatch after setting to uint32_t" << endl;
> > +                     return TestFail;
> > +             }
> > +
> > +             if (value.get<uint32_t>() != 42) {
> > +                     cerr << "Control value mismatch after setting to uint32_t" << endl;
> > +                     return TestFail;
> > +             }
> > +
> > +             if (value.toString() != "42") {
> > +                     cerr << "Control string mismatch after setting to uint32_t" << endl;
> > +                     return TestFail;
> > +             }
> > +
> > +             std::array<uint32_t, 4> uint32s{ 3, 14, 15, 9 };
> > +             value.set(Span<uint32_t>(uint32s));
> > +             if (value.isNone() || !value.isArray() ||
> > +                 value.type() != ControlTypeUnsigned32) {
> > +                     cerr << "Control type mismatch after setting to uint32_t array" << endl;
> > +                     return TestFail;
> > +             }
> > +
> > +             Span<const uint32_t> uint32sResult = value.get<Span<const uint32_t>>();
> > +             if (uint32s.size() != uint32sResult.size() ||
> > +                 !std::equal(uint32s.begin(), uint32s.end(), uint32sResult.begin())) {
> > +                     cerr << "Control value mismatch after setting to uint32_t array" << endl;
> > +                     return TestFail;
> > +             }
> > +
> > +             if (value.toString() != "[ 3, 14, 15, 9 ]") {
> > +                     cerr << "Control string mismatch after setting to uint32_t array" << endl;
> > +                     return TestFail;
> > +             }
> > +
> >               /*
> >                * Integer32 type.
> >                */
> > --
> > 2.47.0.163.g1226f6d8fa-goog
> >


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