Subject: Re: [PATCH 5/6] wl1251: Parse and use MAC address from supplied NVS data

From: Pavel Machek <[email-masked]>
Date: Sat, 24 Dec 2016 19:14:21 +0100

On Sat 2016-12-24 17:53:00, Pali Rohár wrote:
> This patch implements parsing MAC address from NVS data which are sent to
> wl1251 chip. Calibration NVS data could contain valid MAC address and it
> will be used instead randomly generated.

will be used instead of randomly generated one.

> This patch also move code for requesting NVS data from userspace to driver

"moves"

> initialization code to make sure that NVS data will be there at time when
> permanent MAC address is needed.

"at a time"

> Calibration NVS data for wl1251 are model specific. Every one device with

"device specific"? "Every device".

> wl1251 chip should have been calibrated in factory and needs to provide own
> calibration data.
> 
> Default example wl1251-nvs.bin data found in linux-firmware repository and

"are found"

> contains MAC address 00:00:20:07:03:09. So this MAC address is marked as

"contain"

> invalid as it is not real device specific address, just example one.
> 
> Format of calibration NVS data can be found at:
> http://notaz.gp2x.de/misc/pnd/wl1251/nvs_map.txt
> 
> Signed-off-by: Pali Rohár <[email-masked]>
> ---
>  drivers/net/wireless/ti/wl1251/main.c |   39 ++++++++++++++++++++++++++-------
>  1 file changed, 31 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/wireless/ti/wl1251/main.c b/drivers/net/wireless/ti/wl1251/main.c
> index c3fa0b6..1454ba2 100644
> --- a/drivers/net/wireless/ti/wl1251/main.c
> +++ b/drivers/net/wireless/ti/wl1251/main.c
> @@ -205,13 +205,6 @@ static int wl1251_chip_wakeup(struct wl1251 *wl)
>  			goto out;
>  	}
>  
> -	if (wl->nvs == NULL && !wl->use_eeprom) {
> -		/* No NVS from netlink, try to get it from the filesystem */
> -		ret = wl1251_fetch_nvs(wl);
> -		if (ret < 0)
> -			goto out;
> -	}
> -
>  out:
>  	return ret;
>  }
> @@ -1538,6 +1531,30 @@ static int wl1251_read_eeprom_mac(struct wl1251 *wl)
>  	return 0;
>  }
>  
> +static int wl1251_read_nvs_mac(struct wl1251 *wl)
> +{
> +	u8 mac[ETH_ALEN];
> +	int i;
> +
> +	if (wl->nvs_len < 0x24)
> +		return -ENODATA;
> +
> +	/* length is 2 and data address is 0x546c (mask is 0xfffe) */
> +	if (wl->nvs[0x19] != 2 || wl->nvs[0x1a] != 0x6d || wl->nvs[0x1b] != 0x54)
> +		return -EINVAL;
> +
> +	/* MAC is stored in reverse order */
> +	for (i = 0; i < ETH_ALEN; i++)
> +		mac[i] = wl->nvs[0x1c + ETH_ALEN - i - 1];
> +
> +	/* 00:00:20:07:03:09 is in default example wl1251-nvs.bin, so invalid */

remove "default".

> +	if (ether_addr_equal_unaligned(mac, "\x00\x00\x20\x07\x03\x09"))
> +		return -EINVAL;
> +
> +	memcpy(wl->mac_addr, mac, ETH_ALEN);
> +	return 0;
> +}
> +
>  static int wl1251_register_hw(struct wl1251 *wl)
>  {
>  	int ret;
> @@ -1581,10 +1598,16 @@ int wl1251_init_ieee80211(struct wl1251 *wl)
>  
>  	wl->hw->queues = 4;
>  
> +	if (wl->nvs == NULL && !wl->use_eeprom) {
> +		ret = wl1251_fetch_nvs(wl);
> +		if (ret < 0)
> +			goto out;
> +	}

Is goto out here good idea? IMNSHO it is copy&paste bug, it should
just proceed with generating random address.

>  	if (wl->use_eeprom)
>  		ret = wl1251_read_eeprom_mac(wl);
>  	else
> -		ret = -EINVAL;
> +		ret = wl1251_read_nvs_mac(wl);
>  
>  	if (ret == 0 && !is_valid_ether_addr(wl->mac_addr))
>  		ret = -EINVAL;

Best regards,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html