Re: [PATCH v5 2/5] Bluetooth: hci_qca: Deassert RTS while baudrate change command
From: Johan Hovold <johan@kernel.org>
Date: 2019-01-21 08:56:29
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On Fri, Jan 18, 2019 at 04:31:09PM -0800, Matthias Kaehlcke wrote:
On Fri, Jan 18, 2019 at 10:44:16AM +0100, Johan Hovold wrote:quoted
On Thu, Jan 17, 2019 at 09:21:09AM -0800, Matthias Kaehlcke wrote:quoted
I observed that the qcom_geni_serial driver doesn't raise RTS with flow control disabled. It seems we have to investigate why that's the case. I agree that the driver should be platform agnostic.Sounds like a driver bug, unless the hardware is just "odd". The driver implementation of this looks very non-standard judging from a quick peek. In fact, qcom_geni_serial_get_mctrl() is currently a no-op if hardware flow control is not enabled: if (uart_console(uport) || !uart_cts_enabled(uport)) return; Perhaps dropping the !uart_cts_enabled() test is sufficient.Thanks for taking a look Johan, that was indeed the problem (also in set_mctrl()). I posted a fix: https://lore.kernel.org/patchwork/patch/1033611/
Nice (I did mean set_mctrl() above, as I think you noticed).
quoted hunk ↗ jump to hunk
Balakrishna, the following (applied on top of your patch) works for me with the UART patch above:diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c index 9d5e41f159c78f..60bfdf01f72841 100644 --- a/drivers/bluetooth/hci_qca.c +++ b/drivers/bluetooth/hci_qca.c@@ -1080,7 +1080,7 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type) { unsigned int speed, qca_baudrate; struct qca_serdev *qcadev; - int ret; + int ret = 0; if (speed_type == QCA_INIT_SPEED) { speed = qca_get_speed(hu, QCA_INIT_SPEED);@@ -1097,22 +1097,27 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type) * the old speed. */ qcadev = serdev_device_get_drvdata(hu->serdev); - if (qcadev->btsoc_type == QCA_WCN3990) + if (qcadev->btsoc_type == QCA_WCN3990) { + hci_uart_set_flow_control(hu, true);
Wow, yeah, this parameter inversion is indeed confusing...
serdev_device_set_rts(hu->serdev, false); + }
But looking at hci_uart_set_flow_control() now, it actually also deasserts RTS. So all you need here is the hci_uart_set_flow_control() call. And that makes the inversion make a bit more sense too, even if the naming is a bit unfortunate with respect to serdev_device_set_flow_control() at least.
qca_baudrate = qca_get_baudrate_value(speed);
bt_dev_dbg(hu->hdev, "Set UART speed to %d", speed);
ret = qca_set_baudrate(hu->hdev, qca_baudrate);
if (ret)
- return ret;
+ goto out;
host_set_baudrate(hu, speed);
- if (qcadev->btsoc_type == QCA_WCN3990)
+out:
+ if (qcadev->btsoc_type == QCA_WCN3990) {
+ hci_uart_set_flow_control(hu, false);
serdev_device_set_rts(hu->serdev, true);
+ }And same here. Johan