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Subject: Re: [PATCH v4 2/3] Bluetooth: mt7921s: Enable SCO over I2S
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <b12d6dce30c1eeb1dfff2b80b64bdedc0803f40b.1640334021.git.sean.wang@kernel.org>
Date:   Thu, 6 Jan 2022 15:03:04 +0100
Cc:     Johan Hedberg <johan.hedberg@gmail.com>,
        =?utf-8?B?Ik1hcmstWVcgQ2hlbiAo6Zmz5o+a5paHKSI=?= 
        <Mark-YW.Chen@mediatek.com>, Soul.Huang@mediatek.com,
        YN.Chen@mediatek.com, Leon.Yen@mediatek.com,
        Eric-SY.Chang@mediatek.com, Deren.Wu@mediatek.com,
        km.lin@mediatek.com, robin.chiu@mediatek.com,
        Eddie.Chen@mediatek.com, ch.yeh@mediatek.com,
        posh.sun@mediatek.com, ted.huang@mediatek.com,
        Eric.Liang@mediatek.com, Stella.Chang@mediatek.com,
        Tom.Chou@mediatek.com, steve.lee@mediatek.com, jsiuda@google.com,
        frankgor@google.com, jemele@google.com, abhishekpandit@google.com,
        michaelfsun@google.com, mcchou@chromium.org, shawnku@google.com,
        linux-bluetooth@vger.kernel.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org
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Message-Id: <6DDA9D10-3001-4A57-B2F4-9712732868AC@holtmann.org>
References: <91dfa736b7629cdb94bd2029f05717eeae77b07d.1640334021.git.sean.wang@kernel.org>
 <b12d6dce30c1eeb1dfff2b80b64bdedc0803f40b.1640334021.git.sean.wang@kernel.org>
To:     Sean Wang <sean.wang@mediatek.com>
Precedence: bulk

Hi Sean,

> The driver has to issue the specific command to enable Bluetooth SCO over
> the I2S/PCM interface on mt7921s, that is supported since the firmware
> with version 20211222191101 was added, and the patch would not cause any
> harm even when the old firmware is applied.
> 
> The SCO profile with the patch was tested by setting up a VOIP application,
> connected to HFP device, checked telephony function can work normally.
> 
> Co-developed-by: Sean Wang <sean.wang@mediatek.com>
> Signed-off-by: Sean Wang <sean.wang@mediatek.com>
> Signed-off-by: Mark Chen <mark-yw.chen@mediatek.com>
> ---
> v2: refine git message and fix typo
> v3:
>    1. free skb after calling  __hci_cmd_sync
>    2. make bt_awake as const struct btmtk_sco
> v4:
>    1. update git message
>    2. drop a few redundant error messages
> ---
> drivers/bluetooth/btmtk.h     | 20 +++++++++++
> drivers/bluetooth/btmtksdio.c | 68 +++++++++++++++++++++++++++++++++++
> 2 files changed, 88 insertions(+)
> 
> diff --git a/drivers/bluetooth/btmtk.h b/drivers/bluetooth/btmtk.h
> index 2be1d2680ad8..fc57ef09d132 100644
> --- a/drivers/bluetooth/btmtk.h
> +++ b/drivers/bluetooth/btmtk.h
> @@ -7,8 +7,12 @@
> 
> #define HCI_WMT_MAX_EVENT_SIZE		64
> 
> +#define BTMTK_WMT_REG_WRITE 0x1
> #define BTMTK_WMT_REG_READ 0x2
> 
> +#define MT7921_PINMUX_0 0x70005050
> +#define MT7921_PINMUX_1 0x70005054
> +
> enum {
> 	BTMTK_WMT_PATCH_DWNLD = 0x1,
> 	BTMTK_WMT_TEST = 0x2,
> @@ -76,6 +80,22 @@ struct btmtk_wakeon {
> 	__le16 wakeup_delay;
> } __packed;
> 
> +struct btmtk_sco {
> +	u8 clock_config;
> +	u8 transmit_format_config;
> +	u8 channel_format_config;
> +	u8 channel_select_config;
> +} __packed;
> +
> +struct reg_write_cmd {
> +	u8 type;
> +	u8 rsv;
> +	u8 num;
> +	__le32 addr;
> +	__le32 data;
> +	__le32 mask;
> +} __packed;
> +
> struct btmtk_hci_wmt_params {
> 	u8 op;
> 	u8 flag;
> diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
> index 89bd70651e9e..f6fb82b317de 100644
> --- a/drivers/bluetooth/btmtksdio.c
> +++ b/drivers/bluetooth/btmtksdio.c
> @@ -830,6 +830,66 @@ static int btsdio_mtk_reg_read(struct hci_dev *hdev, u32 reg, u32 *val)
> 	return err;
> }
> 
> +static int btsdio_mtk_reg_write(struct hci_dev *hdev, u32 reg, u32 val, u32 mask)
> +{
> +	struct btmtk_hci_wmt_params wmt_params;
> +	struct reg_write_cmd reg_write = {
> +		.type = 1,
> +		.num = 1,
> +		.addr = cpu_to_le32(reg),
> +		.data = cpu_to_le32(val),
> +		.mask = cpu_to_le32(mask),
> +	};

Maybe a good idea to make this const as well.

> +	int err, status;
> +
> +	wmt_params.op = BTMTK_WMT_REGISTER;
> +	wmt_params.flag = BTMTK_WMT_REG_WRITE;
> +	wmt_params.dlen = sizeof(reg_write);
> +	wmt_params.data = &reg_write;
> +	wmt_params.status = &status;
> +
> +	err = mtk_hci_wmt_sync(hdev, &wmt_params);
> +	if (err < 0)
> +		bt_dev_err(hdev, "Failed to write reg(%d)", err);

The please “..reg (%d)” as you have for the other error message.

> +
> +	return err;
> +}
> +
> +static int btsdio_mtk_sco_setting(struct hci_dev *hdev)
> +{
> +	const struct btmtk_sco sco_setting = {
> +		.clock_config = 0x49,
> +		.channel_format_config = 0x80,
> +	};
> +	struct sk_buff *skb;
> +	u32 val;
> +	int err;
> +
> +	/* Enable SCO over I2S/PCM for MediaTek chipset */
> +	skb =  __hci_cmd_sync(hdev, 0xfc72, sizeof(sco_setting),
> +			      &sco_setting, HCI_CMD_TIMEOUT);
> +	if (IS_ERR(skb))
> +		return PTR_ERR(skb);
> +
> +	kfree_skb(skb);
> +
> +	err = btsdio_mtk_reg_read(hdev, MT7921_PINMUX_0, &val);
> +	if (err < 0)
> +		return err;
> +
> +	val |= 0x11000000;
> +	err = btsdio_mtk_reg_write(hdev, MT7921_PINMUX_0, val, ~0);
> +	if (err < 0)
> +		return err;
> +
> +	err = btsdio_mtk_reg_read(hdev, MT7921_PINMUX_1, &val);
> +	if (err < 0)
> +		return err;
> +
> +	val |= 0x00000101;
> +	return btsdio_mtk_reg_write(hdev, MT7921_PINMUX_1, val, ~0);
> +}
> +
> static int btmtksdio_setup(struct hci_dev *hdev)
> {
> 	struct btmtksdio_dev *bdev = hci_get_drvdata(hdev);
> @@ -862,6 +922,14 @@ static int btmtksdio_setup(struct hci_dev *hdev)
> 		err = mt79xx_setup(hdev, fwname);
> 		if (err < 0)
> 			return err;
> +
> +		/* Enable SCO over I2S/PCM */
> +		err = btsdio_mtk_sco_setting(hdev);
> +		if (err < 0) {
> +			bt_dev_err(hdev, "Failed to enable SCO setting (%d)", err);
> +			return err;
> +		}
> +

Is this really a failure or could the chip continue to operate? It just means it falls back to SCO over HCI?

> 		break;
> 	case 0x7663:
> 	case 0x7668:

Regards

Marcel