[PATCH] nvmem: meson-mx-efuse: fix reading from an offset other than 0

[Srinivas Kandagatla]

Hi Martin,
On 12/11/17 18:34, Martin Blumenstingl wrote:
> meson_mx_efuse_read calculates the address internal to the eFuse based
> on the offset and the word size. This works fine with any given offset.
> However, the offset is also included when writing to the output buffer.
> This means that reading 4 bytes at offset 500 tries to write beyond the
> array allocated by the nvmem core as it wants to write the 4 bytes to
> "buffer address + offset (500)".
> This issue did not show up in the previous tests since no driver uses
> any value from the eFuse yet and reading the eFuse via sysfs simply
> reads the whole eFuse, starting at offset 0.
> 
> Fix this by only including the offset in the internal address
> calculation.
> 
> Fixes: 8caef1fa9176 ("nvmem: add a driver for the Amlogic Meson6/Meson8/Meson8b SoCs")
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl at googlemail.com>
> ---
Thanks for your patience,

I will send this to Greg along with other fixes some time this week!

thanks,
srini



>   drivers/nvmem/meson-mx-efuse.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/nvmem/meson-mx-efuse.c b/drivers/nvmem/meson-mx-efuse.c
> index a346b4923550..41d3a3c1104e 100644
> --- a/drivers/nvmem/meson-mx-efuse.c
> +++ b/drivers/nvmem/meson-mx-efuse.c
> @@ -156,8 +156,8 @@ static int meson_mx_efuse_read(void *context, unsigned int offset,
>   				 MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE,
>   				 MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE);
>   
> -	for (i = offset; i < offset + bytes; i += efuse->config.word_size) {
> -		addr = i / efuse->config.word_size;
> +	for (i = 0; i < bytes; i += efuse->config.word_size) {
> +		addr = (offset + i) / efuse->config.word_size;
>   
>   		err = meson_mx_efuse_read_addr(efuse, addr, &tmp);
>   		if (err)
>