RE: [PATCH 1/4] rtw88: Add packed attribute to the eFuse structs

[Ping-Ke Shih <pkshih@realtek.com>]

> -----Original Message-----
> From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> Sent: Wednesday, December 28, 2022 9:36 PM
> To: linux-wireless@vger.kernel.org
> Cc: tony0620emma@gmail.com; kvalo@kernel.org; Ping-Ke Shih <pkshih@realtek.com>; tehuang@realtek.com;
> s.hauer@pengutronix.de; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Martin Blumenstingl
> <martin.blumenstingl@googlemail.com>
> Subject: [PATCH 1/4] rtw88: Add packed attribute to the eFuse structs
> 
> The eFuse definitions in the rtw88 are using structs to describe the
> eFuse contents. Add the packed attribute to all structs used for the
> eFuse description so the compiler doesn't add gaps or re-order
> attributes.
> 
> Also change the type of the res2..res3 eFuse fields to u16 to avoid the
> following warning, now that their surrounding struct has the packed
> attribute:
>   note: offset of packed bit-field 'res2' has changed in GCC 4.4
> 
> Fixes: e3037485c68e ("rtw88: new Realtek 802.11ac driver")
> Fixes: ab0a031ecf29 ("rtw88: 8723d: Add read_efuse to recognize efuse info from map")
> Fixes: 769a29ce2af4 ("rtw88: 8821c: add basic functions")
> Fixes: 87caeef032fc ("wifi: rtw88: Add rtw8723du chipset support")
> Fixes: aff5ffd718de ("wifi: rtw88: Add rtw8821cu chipset support")
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> ---
>  drivers/net/wireless/realtek/rtw88/main.h     |  6 +++---
>  drivers/net/wireless/realtek/rtw88/rtw8723d.h |  6 +++---
>  drivers/net/wireless/realtek/rtw88/rtw8821c.h | 20 +++++++++----------
>  drivers/net/wireless/realtek/rtw88/rtw8822b.h | 20 +++++++++----------
>  drivers/net/wireless/realtek/rtw88/rtw8822c.h | 20 +++++++++----------
>  5 files changed, 36 insertions(+), 36 deletions(-)
> 

[...]

> @@ -43,13 +43,13 @@ struct rtw8821ce_efuse {
>  	u8 link_cap[4];
>  	u8 link_control[2];
>  	u8 serial_number[8];
> -	u8 res0:2;			/* 0xf4 */
> -	u8 ltr_en:1;
> -	u8 res1:2;
> -	u8 obff:2;
> -	u8 res2:3;
> -	u8 obff_cap:2;
> -	u8 res3:4;
> +	u16 res0:2;			/* 0xf4 */
> +	u16 ltr_en:1;
> +	u16 res1:2;
> +	u16 obff:2;
> +	u16 res2:3;
> +	u16 obff_cap:2;
> +	u16 res3:4;

These should be __le16. Though bit fields are suitable to efuse layout, 
we don't access these fields for now. It would be well.

[...]