'\" t
.\"     Title: nand_check_erased_buf
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: April 2019
.\"    Manual: Internal Functions Provided
.\"    Source: Kernel Hackers Manual 4.9.168
.\"  Language: English
.\"
.TH "NAND_CHECK_ERASED_BU" "9" "April 2019" "Kernel Hackers Manual 4\&.9\&." "Internal Functions Provided"
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.SH "NAME"
nand_check_erased_buf \- check if a buffer contains (almost) only 0xff data
.SH "SYNOPSIS"
.HP \w'int\ nand_check_erased_buf('u
.BI "int nand_check_erased_buf(void\ *\ " "buf" ", int\ " "len" ", int\ " "bitflips_threshold" ");"
.SH "ARGUMENTS"
.PP
\fIbuf\fR
.RS 4
buffer to test
.RE
.PP
\fIlen\fR
.RS 4
buffer length
.RE
.PP
\fIbitflips_threshold\fR
.RS 4
maximum number of bitflips
.RE
.SH "DESCRIPTION"
.PP
Check if a buffer contains only 0xff, which means the underlying region has been erased and is ready to be programmed\&. The bitflips_threshold specify the maximum number of bitflips before considering the region is not erased\&.
.SH "NOTE"
.PP
The logic of this function has been extracted from the memweight implementation, except that nand_check_erased_buf function exit before testing the whole buffer if the number of bitflips exceed the bitflips_threshold value\&.
.PP
Returns a positive number of bitflips less than or equal to bitflips_threshold, or \-ERROR_CODE for bitflips in excess of the threshold\&.
.SH "AUTHOR"
.PP
\fBThomas Gleixner\fR <\&tglx@linutronix.de\&>
.RS 4
Author.
.RE
.SH "COPYRIGHT"
.br