Re: [Minios-devel] [UNIKRAFT PATCHv4 1/9] plat/common: Introduce fdt_getprop_u32_by_offset helper

[Jia He <jiakernel2@xxxxxxxxx>]

Hi Sharan

On 2019/4/8 17:20, Sharan Santhanam wrote:
> Hello Jia He,
>
> On 4/8/19 4:59 AM, Jia He wrote:
> > Hi Sharan
> >
> > On 2019/4/4 21:32, Sharan Santhanam wrote:
> > > Hello,
> > >
> > > Please find the review comments inline.
> > >
> > > Thanks & Regards
> > > Sharan
> > >
> > > On 3/27/19 3:34 AM, Jia He wrote:
> > > > From: Jianyong Wu <jianyong.wu@xxxxxxx>
> > > >
> > > > From: Jianyong Wu <jianyong.wu@xxxxxxx>
> > > > This helper will be used very frequently to u32 from properties.
> > > > So we provide this helper here to avoid using fdt_getprop and
> > > > fdt32_to_cpu everywhere.
> > > >
> > > > Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
> > > > Signed-off-by: Jianyong Wu <jianyong.wu@xxxxxxx>
> > > > Signed-off-by: Jia He <justin.he@xxxxxxx>
> > > > ---
> > > >   plat/common/fdt.c         | 59 +++++++++++++++++++++++++++++++++++++++
> > > >   plat/common/include/fdt.h | 59 +++++++++++++++++++++++++++++++++++++++
> > > >   2 files changed, 118 insertions(+)
> > > >   create mode 100644 plat/common/fdt.c
> > > >   create mode 100644 plat/common/include/fdt.h
> > > >
> > > > diff --git a/plat/common/fdt.c b/plat/common/fdt.c
> > > > new file mode 100644
> > > > index 0000000..47f7c74
> > > > --- /dev/null
> > > > +++ b/plat/common/fdt.c
> > > > @@ -0,0 +1,59 @@
> > > > +/* SPDX-License-Identifier: BSD-3-Clause */
> > > > +/*
> > > > + * Authors: Wei Chen <Wei.Chen@xxxxxxx>
> > > > + *          Jianyong Wu <Jianyong.Wu@xxxxxxx>
> > > > + *
> > > > + * Copyright (c) 2018, Arm Ltd. All rights reserved.
> > > > + *
> > > > + * Redistribution and use in source and binary forms, with or without
> > > > + * modification, are permitted provided that the following conditions
> > > > + * are met:
> > > > + *
> > > > + * 1. Redistributions of source code must retain the above copyright
> > > > + *    notice, this list of conditions and the following disclaimer.
> > > > + * 2. Redistributions in binary form must reproduce the above copyright
> > > > + *    notice, this list of conditions and the following disclaimer in the
> > > > + *    documentation and/or other materials provided with the distribution.
> > > > + * 3. Neither the name of the copyright holder nor the names of its
> > > > + *    contributors may be used to endorse or promote products derived from
> > > > + *    this software without specific prior written permission.
> > > > + *
> > > > + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
> > > > "AS IS"
> > > > + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> > > > + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
> > > > PURPOSE
> > > > + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
> > > > + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> > > > + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
> > > > + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
> > > > + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
> > > > + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
> > > > + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 
> > > > THE
> > > > + * POSSIBILITY OF SUCH DAMAGE.
> > > > + *
> > > > + * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
> > > > + */
> > > Why do you prefer to add this to the plat/common instead of adding it to 
> > > the lib/fdt?
> > >  I prefer if we add it the lib/fdt and add this function to exportsyms.uk
> > Ok
> > > > +#include "libfdt_env.h"
> > > > +
> > > > +#include <fdt.h>
> > > > +#include <libfdt.h>
> > > > +
> > > The libfdt_internal.h is internal to the lib/fdt. Why are we including it 
> > > here?
> > > > +#include "libfdt_internal.h"
> > Yes
> > > Prefer to use <> instead of the "" for print.h.
> > > > +#include "uk/print.h"
> > > > +
> > > > +int fdt_getprop_u32_by_offset(const void *fdt, int offset,
> > > > +        const char *name, uint32_t *out)
> > > > +{
> > > > +    const fdt32_t *prop;
> > > > +    int prop_len;
> > > > +
> > > UK_ASSERT(out); or you can report an error?
> > ok
> > > We can call the fdt_get_property_namelen directly as it rest of the functions.
> > ok
> > > > +    prop = fdt_getprop(fdt, offset, name, &prop_len);
> > > > +    if (!prop)
> > > > +        return prop_len;
> > > > +
> > > > +    if (prop_len >= (int)sizeof(fdt32_t)) {
> > > > +        *out = fdt32_to_cpu(prop[0]);
> > > > +        return 0;
> > > > +    }
> > > > +
> > > > +    return -FDT_ERR_NOTFOUND;
> > > > +}
> > > > diff --git a/plat/common/include/fdt.h b/plat/common/include/fdt.h
> > > > new file mode 100644
> > > > index 0000000..8ff88d7
> > > > --- /dev/null
> > > > +++ b/plat/common/include/fdt.h
> > > > @@ -0,0 +1,59 @@
> > > > +/* SPDX-License-Identifier: BSD-3-Clause */
> > > > +/*
> > > > + * Authors: Wei Chen <Wei.Chen@xxxxxxx>
> > > > + *          Jianyong Wu <Jianyong.Wu@xxxxxxx>
> > > > + *
> > > > + * Copyright (c) 2018, Arm Ltd. All rights reserved.
> > > > + *
> > > > + * Redistribution and use in source and binary forms, with or without
> > > > + * modification, are permitted provided that the following conditions
> > > > + * are met:
> > > > + *
> > > > + * 1. Redistributions of source code must retain the above copyright
> > > > + *    notice, this list of conditions and the following disclaimer.
> > > > + * 2. Redistributions in binary form must reproduce the above copyright
> > > > + *    notice, this list of conditions and the following disclaimer in the
> > > > + *    documentation and/or other materials provided with the distribution.
> > > > + * 3. Neither the name of the copyright holder nor the names of its
> > > > + *    contributors may be used to endorse or promote products derived from
> > > > + *    this software without specific prior written permission.
> > > > + *
> > > > + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
> > > > "AS IS"
> > > > + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> > > > + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
> > > > PURPOSE
> > > > + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
> > > > + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> > > > + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
> > > > + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
> > > > + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
> > > > + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
> > > > + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 
> > > > THE
> > > > + * POSSIBILITY OF SUCH DAMAGE.
> > > > + *
> > > > + * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
> > > > + */
> > > There are multiple fdt.h with a similar path. The "fdt.h" from the library 
> > > gets preference because of the order include. We should try and avoid such 
> > > situation.
> > >  1. lib/fdt/include/fdt.h
> > >
> > >  2. plat/common/include/fdt.h
> > Yes, agreed. How about plat/common/include/uk_fdt.h?
> How about
> plat/driver/include/ofw/fdt.h and the implementation needed in plat/driver/ofw/
Sorry, do you mean plat/driver/ofw/fdt.c and plat/driver/include/ofw/fdt.h ?


---
Cheers,
Justin (Jia He)


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