Messages in this thread | | | From | Cheng-yi Chiang <> | Date | Mon, 7 Oct 2019 16:52:41 +0800 | Subject | Re: [PATCH] firmware: vpd: Add an interface to read VPD value |
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On Mon, Oct 7, 2019 at 4:03 PM Tzung-Bi Shih <tzungbi@google.com> wrote: > > On Mon, Oct 7, 2019 at 3:16 PM Cheng-Yi Chiang <cychiang@chromium.org> wrote: > > > > Add an interface for other driver to query VPD value. > > This will be used for ASoC machine driver to query calibration > > data stored in VPD for smart amplifier speaker resistor > > calibration. > > > > Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org> > > --- > > drivers/firmware/google/vpd.c | 16 ++++++++++++++++ > > include/linux/firmware/google/google_vpd.h | 18 ++++++++++++++++++ > > 2 files changed, 34 insertions(+) > > create mode 100644 include/linux/firmware/google/google_vpd.h > > > > diff --git a/drivers/firmware/google/vpd.c b/drivers/firmware/google/vpd.c > > index db0812263d46..71e9d2da63be 100644 > > --- a/drivers/firmware/google/vpd.c > > +++ b/drivers/firmware/google/vpd.c > > @@ -65,6 +65,22 @@ static ssize_t vpd_attrib_read(struct file *filp, struct kobject *kobp, > > info->bin_attr.size); > > } > > > > +int vpd_attribute_read_value(bool ro, const char *key, > > + char **value, u32 value_len) > > +{ > > + struct vpd_attrib_info *info; > > + struct vpd_section *sec = ro ? &ro_vpd : &rw_vpd; > > + > > + list_for_each_entry(info, &sec->attribs, list) { > > + if (strcmp(info->key, key) == 0) { > > + *value = kstrndup(info->value, value_len, GFP_KERNEL); > > Value is not necessary a NULL-terminated string. > kmalloc(info->bin_attr.size) and memcpy(...) would make the most > sense. > > The value_len parameter makes less sense. It seems the caller knows > the length of the value in advance. > Suggest to change the value_len to report the length of value. I.e. > *value_len = info->bin_attr.size; > > Also please check the return value for memory allocation-like > functions (e.g. kstrndup, kmalloc) so that *value won't be NULL but > the function returned 0.
Thanks for the review. I will them in v2.
> > > + return 0; > > + } > > + } > > + return -EINVAL; > > +} > > +EXPORT_SYMBOL(vpd_attribute_read_value); > > + > > /* > > * vpd_section_check_key_name() > > * > > diff --git a/include/linux/firmware/google/google_vpd.h b/include/linux/firmware/google/google_vpd.h > > new file mode 100644 > > index 000000000000..6f1160f28af8 > > --- /dev/null > > +++ b/include/linux/firmware/google/google_vpd.h > > @@ -0,0 +1,18 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +/* > > + * Google VPD interface. > > + * > > + * Copyright 2019 Google Inc. > > + */ > > + > > +/* Interface for reading VPD value on Chrome platform. */ > > + > > +#ifndef __GOOGLE_VPD_H > > +#define __GOOGLE_VPD_H > > + > > +#include <linux/types.h> > > + > > +int vpd_attribute_read_value(bool ro, const char *key, > > + char **value, u32 value_len); > > + > > +#endif /* __GOOGLE_VPD_H */ > > -- > > 2.23.0.581.g78d2f28ef7-goog > >
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