Re: [U-Boot] [PATCH v8 1/4] include: Add log2 and fls64 header fi

[Tom Rini]

On Fri, Oct 23, 2015 at 06:36:27AM +0200, Wolfgang Denk wrote:
> Dear Tom,
> 
> In message <2015102627.GO23893@bill-the-cat> you wrote:
> > 
> > We don't have a hard rule here as we know the kernel will not adopt SPDX
> > tags currently.  For rare sync ups like this probably is, switching to a
> > tag might make sense, for stuff we'll resync every few kernel releases,
> > it's just resync noise possibly so I'll leave that to the people doing
> > the sync.
> 
> In any case the SPDX tag must be added.

Well, it comes down to how much of a PITA that makes re-syncing.  The
tags make life easier but the end goal is the reports.  This reminds me
that I need to go ping some people about the SPDX tooling, there's some
funny things to re-sync and some files to tag.

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Re: [U-Boot] [PATCH v8 1/4] include: Add log2 and fls64 header fi

[Fabio Estevam]

Hi Tom,

On Mon, Oct 19, 2015 at 9:06 PM, Tom Rini  wrote:
> On Fri, Oct 16, 2015 at 05:41:12PM -0300, Fabio Estevam wrote:
>
>> From: Fabio Estevam 
>>
>> Use the log2 and fls64 header files directly from the kernel.
>>
>> Signed-off-by: Fabio Estevam 
>
> Please update based on
> http://www.denx.de/wiki/view/U-Boot/Patches#Attributing_Code_Copyrights_Sign
> to note which kernel hash this comes from.  Similar for the other parts
> as needed.

The need to state the kernel hash or version is clear.

My question is: if we import a file from the kernel should we keep the
license text intact or should it be adapted to the
SPDX-License-Identifier style?
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Re: [U-Boot] [PATCH v8 1/4] include: Add log2 and fls64 header fi

[Tom Rini]

On Thu, Oct 22, 2015 at 07:30:21PM -0200, Fabio Estevam wrote:
> Hi Tom,
> 
> On Mon, Oct 19, 2015 at 9:06 PM, Tom Rini  wrote:
> > On Fri, Oct 16, 2015 at 05:41:12PM -0300, Fabio Estevam wrote:
> >
> >> From: Fabio Estevam 
> >>
> >> Use the log2 and fls64 header files directly from the kernel.
> >>
> >> Signed-off-by: Fabio Estevam 
> >
> > Please update based on
> > http://www.denx.de/wiki/view/U-Boot/Patches#Attributing_Code_Copyrights_Sign
> > to note which kernel hash this comes from.  Similar for the other parts
> > as needed.
> 
> The need to state the kernel hash or version is clear.
> 
> My question is: if we import a file from the kernel should we keep the
> license text intact or should it be adapted to the
> SPDX-License-Identifier style?

We don't have a hard rule here as we know the kernel will not adopt SPDX
tags currently.  For rare sync ups like this probably is, switching to a
tag might make sense, for stuff we'll resync every few kernel releases,
it's just resync noise possibly so I'll leave that to the people doing
the sync.

-- 
Tom


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Re: [U-Boot] [PATCH v8 1/4] include: Add log2 and fls64 header fi

[Wolfgang Denk]

Dear Tom,

In message <2015102627.GO23893@bill-the-cat> you wrote:
> 
> We don't have a hard rule here as we know the kernel will not adopt SPDX
> tags currently.  For rare sync ups like this probably is, switching to a
> tag might make sense, for stuff we'll resync every few kernel releases,
> it's just resync noise possibly so I'll leave that to the people doing
> the sync.

In any case the SPDX tag must be added.

Best regards,

Wolfgang Denk

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Re: [U-Boot] [PATCH v8 1/4] include: Add log2 and fls64 header fi

[Wolfgang Denk]

Dear Fabio,

In message 

Re: [U-Boot] [PATCH v8 1/4] include: Add log2 and fls64 header fi

[Jagan Teki]

On 17 October 2015 at 02:11, Fabio Estevam  wrote:
> From: Fabio Estevam 
>
> Use the log2 and fls64 header files directly from the kernel.
>
> Signed-off-by: Fabio Estevam 
> ---
> Changes since v7:
> - None
>
>  include/asm-generic/bitops/fls64.h |  36 +++
>  include/linux/bitops.h |   9 ++
>  include/linux/log2.h   | 208 
> +
>  3 files changed, 253 insertions(+)
>  create mode 100644 include/asm-generic/bitops/fls64.h
>  create mode 100644 include/linux/log2.h
>
> diff --git a/include/asm-generic/bitops/fls64.h 
> b/include/asm-generic/bitops/fls64.h
> new file mode 100644
> index 000..86d403f
> --- /dev/null
> +++ b/include/asm-generic/bitops/fls64.h
> @@ -0,0 +1,36 @@
> +#ifndef _ASM_GENERIC_BITOPS_FLS64_H_
> +#define _ASM_GENERIC_BITOPS_FLS64_H_
> +
> +#include 
> +
> +/**
> + * fls64 - find last set bit in a 64-bit word
> + * @x: the word to search
> + *
> + * This is defined in a similar way as the libc and compiler builtin
> + * ffsll, but returns the position of the most significant set bit.
> + *
> + * fls64(value) returns 0 if value is 0 or the position of the last
> + * set bit if value is nonzero. The last (most significant) bit is
> + * at position 64.
> + */
> +#if BITS_PER_LONG == 32
> +static inline int fls64(__u64 x)
> +{
> +   __u32 h = x >> 32;
> +   if (h)
> +   return fls(h) + 32;
> +   return fls(x);
> +}
> +#elif BITS_PER_LONG == 64
> +static inline int fls64(__u64 x)
> +{
> +   if (x == 0)
> +   return 0;
> +   return __fls(x) + 1;
> +}
> +#else
> +#error BITS_PER_LONG not 32 or 64
> +#endif
> +
> +#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */
> diff --git a/include/linux/bitops.h b/include/linux/bitops.h
> index 7d30ace..647733f 100644
> --- a/include/linux/bitops.h
> +++ b/include/linux/bitops.h
> @@ -129,6 +129,15 @@ static inline unsigned int generic_hweight8(unsigned int 
> w)
>  # define fls generic_fls
>  #endif
>
> +#include 

Please check this include, we can't assume to use generic one in
common header file there is one more fls64 from powerpc?

> +
> +static inline unsigned fls_long(unsigned long l)
> +{
> +   if (sizeof(l) == 4)
> +   return fls(l);
> +   return fls64(l);
> +}
> +
>  /**
>   * __set_bit - Set a bit in memory
>   * @nr: the bit to set
> diff --git a/include/linux/log2.h b/include/linux/log2.h
> new file mode 100644
> index 000..fd7ff3d
> --- /dev/null
> +++ b/include/linux/log2.h
> @@ -0,0 +1,208 @@
> +/* Integer base 2 logarithm calculation
> + *
> + * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
> + * Written by David Howells (dhowe...@redhat.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.
> + */

Wolfgang Denk/Tom,

This file is copied from Linux, will this license notes will also be
same or any changes?

> +
> +#ifndef _LINUX_LOG2_H
> +#define _LINUX_LOG2_H
> +
> +#include 
> +#include 
> +
> +/*
> + * deal with unrepresentable constant logarithms
> + */
> +extern __attribute__((const, noreturn))
> +int ilog2_NaN(void);
> +
> +/*
> + * non-constant log of base 2 calculators
> + * - the arch may override these in asm/bitops.h if they can be implemented
> + *   more efficiently than using fls() and fls64()
> + * - the arch is not required to handle n==0 if implementing the fallback
> + */
> +#ifndef CONFIG_ARCH_HAS_ILOG2_U32
> +static inline __attribute__((const))
> +int __ilog2_u32(u32 n)
> +{
> +   return fls(n) - 1;
> +}
> +#endif
> +
> +#ifndef CONFIG_ARCH_HAS_ILOG2_U64
> +static inline __attribute__((const))
> +int __ilog2_u64(u64 n)
> +{
> +   return fls64(n) - 1;
> +}
> +#endif
> +
> +/*
> + *  Determine whether some value is a power of two, where zero is
> + * *not* considered a power of two.
> + */
> +
> +static inline __attribute__((const))
> +bool is_power_of_2(unsigned long n)
> +{
> +   return (n != 0 && ((n & (n - 1)) == 0));
> +}
> +
> +/*
> + * round up to nearest power of two
> + */
> +static inline __attribute__((const))
> +unsigned long __roundup_pow_of_two(unsigned long n)
> +{
> +   return 1UL << fls_long(n - 1);
> +}
> +
> +/*
> + * round down to nearest power of two
> + */
> +static inline __attribute__((const))
> +unsigned long __rounddown_pow_of_two(unsigned long n)
> +{
> +   return 1UL << (fls_long(n) - 1);
> +}
> +
> +/**
> + * ilog2 - log of base 2 of 32-bit or a 64-bit unsigned value
> + * @n - parameter
> + *
> + * constant-capable log of base 2 calculation
> + * - this can be used to initialise global variables from constant data, 
> hence
> + *   the massive ternary operator construction
> + *
> + * selects the appropriately-sized optimised version 

Re: [U-Boot] [PATCH v8 1/4] include: Add log2 and fls64 header fi

[Tom Rini]

On Fri, Oct 16, 2015 at 05:41:12PM -0300, Fabio Estevam wrote:

> From: Fabio Estevam 
> 
> Use the log2 and fls64 header files directly from the kernel.
> 
> Signed-off-by: Fabio Estevam 

Please update based on
http://www.denx.de/wiki/view/U-Boot/Patches#Attributing_Code_Copyrights_Sign
to note which kernel hash this comes from.  Similar for the other parts
as needed.

-- 
Tom


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[U-Boot] [PATCH v8 1/4] include: Add log2 and fls64 header fi

[Fabio Estevam]

From: Fabio Estevam 

Use the log2 and fls64 header files directly from the kernel.

Signed-off-by: Fabio Estevam 
---
Changes since v7:
- None

 include/asm-generic/bitops/fls64.h |  36 +++
 include/linux/bitops.h |   9 ++
 include/linux/log2.h   | 208 +
 3 files changed, 253 insertions(+)
 create mode 100644 include/asm-generic/bitops/fls64.h
 create mode 100644 include/linux/log2.h

diff --git a/include/asm-generic/bitops/fls64.h 
b/include/asm-generic/bitops/fls64.h
new file mode 100644
index 000..86d403f
--- /dev/null
+++ b/include/asm-generic/bitops/fls64.h
@@ -0,0 +1,36 @@
+#ifndef _ASM_GENERIC_BITOPS_FLS64_H_
+#define _ASM_GENERIC_BITOPS_FLS64_H_
+
+#include 
+
+/**
+ * fls64 - find last set bit in a 64-bit word
+ * @x: the word to search
+ *
+ * This is defined in a similar way as the libc and compiler builtin
+ * ffsll, but returns the position of the most significant set bit.
+ *
+ * fls64(value) returns 0 if value is 0 or the position of the last
+ * set bit if value is nonzero. The last (most significant) bit is
+ * at position 64.
+ */
+#if BITS_PER_LONG == 32
+static inline int fls64(__u64 x)
+{
+   __u32 h = x >> 32;
+   if (h)
+   return fls(h) + 32;
+   return fls(x);
+}
+#elif BITS_PER_LONG == 64
+static inline int fls64(__u64 x)
+{
+   if (x == 0)
+   return 0;
+   return __fls(x) + 1;
+}
+#else
+#error BITS_PER_LONG not 32 or 64
+#endif
+
+#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 7d30ace..647733f 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -129,6 +129,15 @@ static inline unsigned int generic_hweight8(unsigned int w)
 # define fls generic_fls
 #endif
 
+#include 
+
+static inline unsigned fls_long(unsigned long l)
+{
+   if (sizeof(l) == 4)
+   return fls(l);
+   return fls64(l);
+}
+
 /**
  * __set_bit - Set a bit in memory
  * @nr: the bit to set
diff --git a/include/linux/log2.h b/include/linux/log2.h
new file mode 100644
index 000..fd7ff3d
--- /dev/null
+++ b/include/linux/log2.h
@@ -0,0 +1,208 @@
+/* Integer base 2 logarithm calculation
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowe...@redhat.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.
+ */
+
+#ifndef _LINUX_LOG2_H
+#define _LINUX_LOG2_H
+
+#include 
+#include 
+
+/*
+ * deal with unrepresentable constant logarithms
+ */
+extern __attribute__((const, noreturn))
+int ilog2_NaN(void);
+
+/*
+ * non-constant log of base 2 calculators
+ * - the arch may override these in asm/bitops.h if they can be implemented
+ *   more efficiently than using fls() and fls64()
+ * - the arch is not required to handle n==0 if implementing the fallback
+ */
+#ifndef CONFIG_ARCH_HAS_ILOG2_U32
+static inline __attribute__((const))
+int __ilog2_u32(u32 n)
+{
+   return fls(n) - 1;
+}
+#endif
+
+#ifndef CONFIG_ARCH_HAS_ILOG2_U64
+static inline __attribute__((const))
+int __ilog2_u64(u64 n)
+{
+   return fls64(n) - 1;
+}
+#endif
+
+/*
+ *  Determine whether some value is a power of two, where zero is
+ * *not* considered a power of two.
+ */
+
+static inline __attribute__((const))
+bool is_power_of_2(unsigned long n)
+{
+   return (n != 0 && ((n & (n - 1)) == 0));
+}
+
+/*
+ * round up to nearest power of two
+ */
+static inline __attribute__((const))
+unsigned long __roundup_pow_of_two(unsigned long n)
+{
+   return 1UL << fls_long(n - 1);
+}
+
+/*
+ * round down to nearest power of two
+ */
+static inline __attribute__((const))
+unsigned long __rounddown_pow_of_two(unsigned long n)
+{
+   return 1UL << (fls_long(n) - 1);
+}
+
+/**
+ * ilog2 - log of base 2 of 32-bit or a 64-bit unsigned value
+ * @n - parameter
+ *
+ * constant-capable log of base 2 calculation
+ * - this can be used to initialise global variables from constant data, hence
+ *   the massive ternary operator construction
+ *
+ * selects the appropriately-sized optimised version depending on sizeof(n)
+ */
+#define ilog2(n)   \
+(  \
+   __builtin_constant_p(n) ? ( \
+   (n) < 1 ? ilog2_NaN() : \
+   (n) & (1ULL << 63) ? 63 :   \
+   (n) & (1ULL << 62) ? 62 :   \
+   (n) & (1ULL << 61) ? 61 :   \
+   (n) & (1ULL << 60) ? 60 :   \
+   (n) & (1ULL << 59) ? 59 :   \
+   (n) & (1ULL << 58) ? 58 :   \
+   (n) & (1ULL << 57) ? 57 :   \
+   (n) & (1ULL << 56) ? 56 :   \
+   (n) &