linux-kernel - Re: [PATCH v1 1/1] scripts: dtc: mask flags bit when check i2c addr

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Date:   Fri, 28 Feb 2020 07:49:57 -0600
From:   Rob Herring <robh+dt@...nel.org>
To:     Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
Cc:     Frank Rowand <frowand.list@...il.com>, devicetree@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <bcm-kernel-feedback-list@...adcom.com>
Subject: Re: [PATCH v1 1/1] scripts: dtc: mask flags bit when check i2c addr

On Fri, Feb 28, 2020 at 2:48 AM Rayagonda Kokatanur
<rayagonda.kokatanur@...adcom.com> wrote:
>
> Generally i2c addr should not be greater than 10-bit. The highest 2 bits
> are used for I2C_TEN_BIT_ADDRESS and I2C_OWN_SLAVE_ADDRESS. Need to mask
> these flags if check slave addr valid.
>
> Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
> ---
>  scripts/dtc/Makefile | 2 +-
>  scripts/dtc/checks.c | 5 +++++
>  2 files changed, 6 insertions(+), 1 deletion(-)

dtc changes must be submitted against upstream dtc.


> diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
> index 3acbb410904c..c5e8d6a9e73c 100644
> --- a/scripts/dtc/Makefile
> +++ b/scripts/dtc/Makefile
> @@ -9,7 +9,7 @@ dtc-objs        := dtc.o flattree.o fstree.o data.o livetree.o treesource.o \
>  dtc-objs       += dtc-lexer.lex.o dtc-parser.tab.o
>
>  # Source files need to get at the userspace version of libfdt_env.h to compile
> -HOST_EXTRACFLAGS := -I $(srctree)/$(src)/libfdt
> +HOST_EXTRACFLAGS := -I $(srctree)/$(src)/libfdt -I$(srctree)/tools/include
>
>  ifeq ($(shell pkg-config --exists yaml-0.1 2>/dev/null && echo yes),)
>  ifneq ($(CHECK_DTBS),)
> diff --git a/scripts/dtc/checks.c b/scripts/dtc/checks.c
> index 756f0fa9203f..17c9ed4137b5 100644
> --- a/scripts/dtc/checks.c
> +++ b/scripts/dtc/checks.c
> @@ -3,6 +3,7 @@
>   * (C) Copyright David Gibson <dwg@....ibm.com>, IBM Corporation.  2007.
>   */
>
> +#include <linux/bits.h>

Not a UAPI header not that that would be much better as dtc also builds on Mac.

>  #include "dtc.h"
>  #include "srcpos.h"
>
> @@ -17,6 +18,9 @@
>  #define TRACE(c, fmt, ...)     do { } while (0)
>  #endif
>
> +#define I2C_TEN_BIT_ADDRESS    BIT(31)
> +#define I2C_OWN_SLAVE_ADDRESS  BIT(30)
> +
>  enum checkstatus {
>         UNCHECKED = 0,
>         PREREQ,
> @@ -1048,6 +1052,7 @@ static void check_i2c_bus_reg(struct check *c, struct dt_info *dti, struct node
>
>         for (len = prop->val.len; len > 0; len -= 4) {
>                 reg = fdt32_to_cpu(*(cells++));
> +               reg &= ~(I2C_OWN_SLAVE_ADDRESS | I2C_TEN_BIT_ADDRESS);

I'd just mask the top byte so we don't have to update on the next flag we add.

Rob