linux-kernel - Re: [PATCH v11 7/7] Bluetooth: hci_qca: Add support for Qualcomm Bluetooth chip wcn3990

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180730205502.GC68975@google.com>
Date:   Mon, 30 Jul 2018 13:55:02 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Balakrishna Godavarthi <bgodavar@...davar-linux.qualcomm.com>
Cc:     marcel@...tmann.org, johan.hedberg@...il.com,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-bluetooth@...r.kernel.org, thierry.escande@...aro.org,
        rtatiya@...eaurora.org, hemantg@...eaurora.org,
        linux-arm-msm@...r.kernel.org,
        Balakrishna Godavarthi <bgodavar@...eaurora.org>
Subject: Re: [PATCH v11 7/7] Bluetooth: hci_qca: Add support for Qualcomm
 Bluetooth chip wcn3990

On Fri, Jul 27, 2018 at 07:43:20PM +0530, Balakrishna Godavarthi wrote:
> From: Balakrishna Godavarthi <bgodavar@...eaurora.org>
> 
> Add support to set voltage/current of various regulators
> to power up/down Bluetooth chip wcn3990.
> 
> Signed-off-by: Balakrishna Godavarthi <bgodavar@...eaurora.org>
> ---
> Changes in v11:
>     * removed support to read regulator currents from dts.	
>     * updated review comments.

Updated regulator voltage ranges?

> +static int qca_wcn3990_init(struct hci_uart *hu, u32 *soc_ver)
> +{
> +	struct hci_dev *hdev = hu->hdev;
> +	int i, ret;
> +
> +	/* wcn3990 is a discrete Bluetooth chip connected to SoC.
> +	 * sometimes we will face communication synchronization issues,
> +	 * like reading version command timeouts. In which HCI_SETUP fails,
> +	 * to overcome these issues, we try to communicate by performing an
> +	 * cold power off and on.
> +	 */
> +	for (i = 0; i <= 3; i++) {
> +		ret = qca_power_setup(hu, true);
> +		if (ret)
> +			goto regs_off;
> +
> +		/* Forcefully enable wcn3990 to enter in to boot mode. */
> +		host_set_baudrate(hu, 2400);
> +		ret = qca_send_power_pulse(hdev, QCA_WCN3990_POWEROFF_PULSE);
> +		if (ret)
> +			goto regs_off;
> +
> +		qca_set_speed(hu, QCA_INIT_SPEED);
> +		ret = qca_send_power_pulse(hdev, QCA_WCN3990_POWERON_PULSE);
> +		if (ret)
> +			goto regs_off;
> +
> +		/* Wait for 100 ms for SoC to boot */
> +		msleep(100);
> +
> +		/* Now the device is in ready state to communicate with host.
> +		 * To sync host with device we need to reopen port.
> +		 * Without this, we will have RTS and CTS synchronization
> +		 * issues.
> +		 */
> +		serdev_device_close(hu->serdev);
> +		ret = serdev_device_open(hu->serdev);
> +		if (ret) {
> +			bt_dev_err(hu->hdev, "failed to open port");
> +			break;
> +		}
> +
> +		hci_uart_set_flow_control(hu, false);
> +		ret = qca_read_soc_version(hdev, soc_ver);
> +
> +		if (!ret)
> +			break;
> +
> +regs_off:
> +		bt_dev_err(hdev, "retrying to establish communication: %d",
> +			   i + 1);
> +		qca_power_shutdown(hdev);
> +	}
> +
> +	return ret;
> +}

I'm still not convinced that the retry loop is needed/desirable, I
commented on the discussion on v10.

> +static const struct qca_vreg_data qca_soc_data = {
> +	.soc_type = QCA_WCN3990,
> +	.vregs = (struct qca_vreg []) {
> +		{ "vddio",   1800000, 1900000,  15000  },
> +		{ "vddxo",   1800000, 1900000,  80000  },
> +		{ "vddrf",   1300000, 1350000,  300000 },
> +		{ "vddch0",  3300000, 3400000,  450000 },
> +	},

In v10 this was:

		{ "vddio",   1800000, 1800000,  15000  },
		{ "vddxo",   1800000, 1800000,  80000  },
		{ "vddrf",   1304000, 1304000,  300000 },
		{ "vddch0",  3000000, 3312000,  450000 },

I don't have concerns about the new voltage ranges, but you should
mention such changes in the changelog, ideally with a brief
description why the change was made.