[PATCH 2/2] wifi: mt76: mt792x: fix mt7925u USB WFSYS reset handling

[Nick]

> From: Sean Wang <sean.wang at mediatek.com>
>
> mt7925u uses different reset/status registers from mt7921u. Reusing the
> mt7921u register set causes the WFSYS reset to fail.
>
> Add a chip-specific descriptor in mt792xu_wfsys_reset() to select the
> correct registers and fix mt7925u failing to initialize after a warm
> reboot.
>
> Fixes: d28e1a48952e ("wifi: mt76: mt792x: introduce mt792x-usb module")
> Cc: stable at vger.kernel.org
> Signed-off-by: Sean Wang <sean.wang at mediatek.com>
> ---
>  drivers/net/wireless/mediatek/mt76/mt792x_regs.h |  4 ++++
>  drivers/net/wireless/mediatek/mt76/mt792x_usb.c  | 13 ++++++++++++-
>  2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_regs.h b/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
> index 7ddde9286861..d2a8b2b0df32 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
> +++ b/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
> @@ -392,6 +392,10 @@
>  #define MT_CBTOP_RGU_WF_SUBSYS_RST     MT_CBTOP_RGU(0x600)
>  #define MT_CBTOP_RGU_WF_SUBSYS_RST_WF_WHOLE_PATH BIT(0)
>
> +#define MT7925_CBTOP_RGU_WF_SUBSYS_RST 0x70028600
> +#define MT7925_WFSYS_INIT_DONE_ADDR    0x184c1604
> +#define MT7925_WFSYS_INIT_DONE         0x00001d1e
> +
>  #define MT_HW_BOUND                    0x70010020
>  #define MT_HW_CHIPID                   0x70010200
>  #define MT_HW_REV                      0x70010204
> diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_usb.c b/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
> index a92e872226cf..47827d1c5ccb 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
> @@ -224,6 +224,15 @@ static const struct mt792xu_wfsys_desc mt7921_wfsys_desc = {
>         .need_status_sel = true,
>  };
>
> +static const struct mt792xu_wfsys_desc mt7925_wfsys_desc = {
> +       .rst_reg = MT7925_CBTOP_RGU_WF_SUBSYS_RST,
> +       .done_reg = MT7925_WFSYS_INIT_DONE_ADDR,
> +       .done_mask = U32_MAX,
> +       .done_val = MT7925_WFSYS_INIT_DONE,
> +       .delay_ms = 20,
> +       .need_status_sel = false,
> +};
> +
>  int mt792xu_dma_init(struct mt792x_dev *dev, bool resume)
>  {
>         int err;
> @@ -254,7 +263,9 @@ EXPORT_SYMBOL_GPL(mt792xu_dma_init);
>
>  int mt792xu_wfsys_reset(struct mt792x_dev *dev)
>  {
> -       const struct mt792xu_wfsys_desc *desc = &mt7921_wfsys_desc;
> +       const struct mt792xu_wfsys_desc *desc = is_mt7925(&dev->mt76) ?
> +                                               &mt7925_wfsys_desc :
> +                                               &mt7921_wfsys_desc;
>         u32 val;
>         int i;
>
> --
> 2.43.0
>

Sean, testing results from: Satadru Pramanik <satadru at gmail.com>

"The updated patches from
https://patchwork.kernel.org/project/linux-wireless/list/?series=1064695
do NOT work. I get the -110 error with them on a warm reboot.
Reverting to the kernel with the older patch restores my adapter
connection on a warm reboot."

You are welcome to stop by the Github issue where this issue is being discussed:

https://github.com/morrownr/USB-WiFi/issues/688#

Nick