linux-kernel - Re: [PATCH 1/2] firmware: Google VPD: import lib

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Date:   Tue, 11 Apr 2017 16:11:07 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Thierry Escande <thierry.escande@...labora.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] firmware: Google VPD: import lib_vpd source files

On Tue, Apr 11, 2017 at 04:10:12PM +0200, Greg Kroah-Hartman wrote:
> On Tue, Apr 11, 2017 at 11:14:30AM +0200, Thierry Escande wrote:
> > From: Wei-Ning Huang <wnhuang@...gle.com>
> > 
> > This patch imports lib_vpd.h and vpd_decode.c from the Chromium Vital
> > Product Data project.
> > 
> > This library is used to parse VPD sections obtained from coreboot table
> > entries describing Chromebook devices product data. Only the sections of
> > type VPD_TYPE_STRING are decoded.
> > 
> > The VPD string sections in the coreboot tables contain the type (1 byte
> > set to 0x01 for strings), the key length, the key ascii array, the value
> > length, and the value ascii array. The key and value arrays are not null
> > terminated.
> > 
> > Signed-off-by: Wei-Ning Huang <wnhuang@...gle.com>
> > Signed-off-by: Thierry Escande <thierry.escande@...labora.com>
> > ---
> >  drivers/firmware/google/vpd_decode.c | 99 ++++++++++++++++++++++++++++++++++++
> >  drivers/firmware/google/vpd_decode.h | 59 +++++++++++++++++++++
> >  2 files changed, 158 insertions(+)
> >  create mode 100644 drivers/firmware/google/vpd_decode.c
> >  create mode 100644 drivers/firmware/google/vpd_decode.h
> > 
> > diff --git a/drivers/firmware/google/vpd_decode.c b/drivers/firmware/google/vpd_decode.c
> > new file mode 100644
> > index 0000000..75e4027
> > --- /dev/null
> > +++ b/drivers/firmware/google/vpd_decode.c
> > @@ -0,0 +1,99 @@
> > +/*
> > + * vpd_decode.c
> > + *
> > + * Google VPD decoding routines.
> > + *
> > + * Copyright 2017 Google Inc.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License v2.0 as published by
> > + * the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +#include <linux/export.h>
> > +
> > +#include "vpd_decode.h"
> > +
> > +static int decode_len(const int32_t max_len, const uint8_t *in,
> > +		      int32_t *length, int32_t *decoded_len)
> > +{
> > +	uint8_t more;
> > +	int i = 0;
> > +
> > +	if (!length || !decoded_len)
> > +		return VPD_FAIL;
> > +
> > +	*length = 0;
> > +	do {
> > +		if (i >= max_len)
> > +			return VPD_FAIL;
> > +
> > +		more = in[i] & 0x80;
> > +		*length <<= 7;
> > +		*length |= in[i] & 0x7f;
> > +		++i;
> > +	} while (more);
> > +
> > +	*decoded_len = i;
> > +
> > +	return VPD_OK;
> > +}
> > +
> > +int decode_vpd_string(const int32_t max_len, const uint8_t *input_buf,
> > +		      int32_t *consumed, vpd_decode_callback callback,
> > +		      void *callback_arg)
> > +{
> > +	int type;
> > +	int res;
> > +	int32_t key_len, value_len;
> > +	int32_t decoded_len;
> > +	const uint8_t *key, *value;
> > +
> > +	/* type */
> > +	if (*consumed >= max_len)
> > +		return VPD_FAIL;
> > +
> > +	type = input_buf[*consumed];
> > +
> > +	switch (type) {
> > +	case VPD_TYPE_INFO:
> > +	case VPD_TYPE_STRING:
> > +		(*consumed)++;
> > +
> > +		/* key */
> > +		res = decode_len(max_len - *consumed, &input_buf[*consumed],
> > +				 &key_len, &decoded_len);
> > +		if (res != VPD_OK || *consumed + decoded_len >= max_len)
> > +			return VPD_FAIL;
> > +
> > +		*consumed += decoded_len;
> > +		key = &input_buf[*consumed];
> > +		*consumed += key_len;
> > +
> > +		/* value */
> > +		res = decode_len(max_len - *consumed, &input_buf[*consumed],
> > +				 &value_len, &decoded_len);
> > +		if (res != VPD_OK || *consumed + decoded_len > max_len)
> > +			return VPD_FAIL;
> > +
> > +		*consumed += decoded_len;
> > +		value = &input_buf[*consumed];
> > +		*consumed += value_len;
> > +
> > +		if (type == VPD_TYPE_STRING)
> > +			return callback(key, key_len, value, value_len,
> > +					callback_arg);
> > +		break;
> > +
> > +	default:
> > +		return VPD_FAIL;
> > +	}
> > +
> > +	return VPD_OK;
> > +}
> > +EXPORT_SYMBOL(decode_vpd_string);
> 
> Normally put the prefix for the driver you are exporting from:
> 	vpd_string_decode()?
> 
> And EXPORT_SYMBOL_GPL() perhaps?

Wait, why is this even exported?  You build this into the module that
needs it...