Re: [DONOTAPPLY RFC PATCH v2 3/4] DONOTMERGE: net: mwifiex: fix timeouts with the SD8777 chip

[Brian Norris <briannorris@chromium.org>]

Hi,

On Sun, Oct 26, 2025 at 07:20:40PM +0100, Karel Balej wrote:
> 	[ 2101.211178] mwifiex_sdio mmc2:0001:1: info: MWIFIEX VERSION: mwifiex 1.0 (14.75.33.p119)
... 
> Afterwards, a bisect was
> performed which first indicated the commit 808bbebcc8fc ("mwifiex: add
> Tx status support for EAPOL packets") introduced in the v3.18-v3.19
> cycle.
> 
> Reverting this commit (and the following one, commit 18ca43823f3c
> ("mwifiex: add Tx status support for ACTION frames"), to facilitate a
> clean revert) fixed the timeouts for v3.19, but during the next cycle,
> v3.19-v4.0, another breakage was introduced via commit 84b313b35f81
> ("mwifiex: make tx packet 64 byte DMA aligned").
> 
> Reverting all three commits fixed the timeouts on the current mainline
> kernel also. This patch contains the minimal changes needed to achieve
> that derived from the full revert commits.
...

(Trimmed the commit message down to the breaking commits, and the
version info)

From the looks of it, you're dealing with incompatible changes made in
the Marvell firmware API. It seems that you have a "version 14"
firmware, and the timeline of these mwifiex changes (~2014) is approx
when linux-firmware started seeing v15 and v16 firmware. It *might* be
OK to try add some versioning to these structs and padding changes, and
make a choice based on adapter->fw_release_number or
adapter->fw_cap_info. It might be ugly and error-prone, but possible...

Or if the FW versioning doesn't work out, it's possible we could
specifically flag these quirks for SD8777 somehow.

> Signed-off-by: Karel Balej <balejk@matfyz.cz>
> ---
>  drivers/net/wireless/marvell/mwifiex/fw.h     |  4 +---
>  drivers/net/wireless/marvell/mwifiex/sta_tx.c | 10 ++--------
>  2 files changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h
> index e9e896606912..5c4c3363c7de 100644
> --- a/drivers/net/wireless/marvell/mwifiex/fw.h
> +++ b/drivers/net/wireless/marvell/mwifiex/fw.h
> @@ -690,9 +690,7 @@ struct txpd {
>  	u8 priority;
>  	u8 flags;
>  	u8 pkt_delay_2ms;
> -	u8 reserved1[2];
> -	u8 tx_token_id;
> -	u8 reserved[2];
> +	u8 reserved1;

I'm inferring that 'sizeof(struct txpd)' (also spelled
'sizeof(*local_tx_pd)' below) is relevant, and that this struct probably
should retain the smaller size for FW version 14.

Maybe you need a new 'struct txpd_v14' layout, and embed that inside
'struct txpd'.

>  } __packed;
>  
>  struct rxpd {
> diff --git a/drivers/net/wireless/marvell/mwifiex/sta_tx.c b/drivers/net/wireless/marvell/mwifiex/sta_tx.c
> index 9d0ef04ebe02..857eb22f4c24 100644
> --- a/drivers/net/wireless/marvell/mwifiex/sta_tx.c
> +++ b/drivers/net/wireless/marvell/mwifiex/sta_tx.c
> @@ -41,8 +41,8 @@ void mwifiex_process_sta_txpd(struct mwifiex_private *priv,
>  
>  	pkt_type = mwifiex_is_skb_mgmt_frame(skb) ? PKT_TYPE_MGMT : 0;
>  
> -	pad = ((uintptr_t)skb->data - (sizeof(*local_tx_pd) + hroom)) &
> -	       (MWIFIEX_DMA_ALIGN_SZ - 1);
> +	pad = (4 - (((void *)skb->data - NULL) & 0x3)) % 4;

It's not clear to me whether your v14 FW doesn't like the 64-byte
alignment, or if it didn't like the new txpd header size/layout, or
both. But obviously this line won't fly, with magic numbers and all. It
will need to be expressed in terms of macros (MWIFIEX_DMA_ALIGN_SZ, or a
"V14" version of that; and sizeof(...)).

> +
>  	skb_push(skb, sizeof(*local_tx_pd) + pad);
>  
>  	local_tx_pd = (struct txpd *) skb->data;
> @@ -58,12 +58,6 @@ void mwifiex_process_sta_txpd(struct mwifiex_private *priv,
>  	local_tx_pd->pkt_delay_2ms =
>  				mwifiex_wmm_compute_drv_pkt_delay(priv, skb);
>  
> -	if (tx_info->flags & MWIFIEX_BUF_FLAG_EAPOL_TX_STATUS ||
> -	    tx_info->flags & MWIFIEX_BUF_FLAG_ACTION_TX_STATUS) {
> -		local_tx_pd->tx_token_id = tx_info->ack_frame_id;
> -		local_tx_pd->flags |= MWIFIEX_TXPD_FLAGS_REQ_TX_STATUS;
> -	}

Rather than dropping this block, would it work to also check:

	adapter->fw_api_ver >= MWIFIEX_FW_V15

?

Brian

> -
>  	if (local_tx_pd->priority <
>  	    ARRAY_SIZE(priv->wmm.user_pri_pkt_tx_ctrl))
>  		/*
> -- 
> 2.51.1
>