Re: [PATCH v9 7/7] Bluetooth: hci_qca: Add support for Qualcomm Bluetooth chip wcn3990

From: Balakrishna Godavarthi
Date: Mon Jul 16 2018 - 09:52:04 EST

Hi Matthias,

On 2018-07-07 03:51, Matthias Kaehlcke wrote:
On Thu, Jul 05, 2018 at 10:25:15PM +0530, Balakrishna Godavarthi wrote:
Add support to set voltage/current of various regulators
to power up/down Bluetooth chip wcn3990.

Signed-off-by: Balakrishna Godavarthi <bgodavar@xxxxxxxxxxxxxx>
---
changes in v9:
* moved flow control to vendor and set_baudarte functions.
* removed parent regs.

changes in v8:
* closing qca buffer, if qca_power_setup fails
* chnaged ibs start timer function call location.
* updated review comments.

changes in v7:
* addressed review comments.

changes in v6:
* Hooked up qca_power to qca_serdev.
* renamed all the naming inconsistency functions with qca_*
* leveraged common code of ROME for wcn3990.
* created wrapper functions for re-usable blocks.
* updated function of _*regulator_enable and _*regualtor_disable.
* removed redundant comments and functions.
* addressed review comments.

Changes in v5:
* updated regulator vddpa min_uV to 1304000.
* addressed review comments.

Changes in v4:
* Segregated the changes of btqca from hci_qca
* rebased all changes on top of bluetooth-next.
* addressed review comments.

---
drivers/bluetooth/btqca.h | 3 +
drivers/bluetooth/hci_qca.c | 387 +++++++++++++++++++++++++++++++-----
2 files changed, 345 insertions(+), 45 deletions(-)

diff --git a/drivers/bluetooth/btqca.h b/drivers/bluetooth/btqca.h
index a9c2779f3e07..0c01f375fe83 100644
--- a/drivers/bluetooth/btqca.h
+++ b/drivers/bluetooth/btqca.h
@@ -37,6 +37,9 @@
#define EDL_TAG_ID_HCI (17)
#define EDL_TAG_ID_DEEP_SLEEP (27)

+#define QCA_WCN3990_POWERON_PULSE 0xFC
+#define QCA_WCN3990_POWEROFF_PULSE 0xC0
+
enum qca_bardrate {
QCA_BAUDRATE_115200 = 0,
QCA_BAUDRATE_57600,
diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index 7ebfaa0edf3f..d62c7785a618 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -5,7 +5,7 @@
* protocol extension to H4.
*
* Copyright (C) 2007 Texas Instruments, Inc.
- * Copyright (c) 2010, 2012 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2010, 2012, 2018 The Linux Foundation. All rights reserved.
*
* Acknowledgements:
* This file is based on hci_ll.c, which was...
@@ -31,9 +31,14 @@
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
#include <linux/serdev.h>

#include <net/bluetooth/bluetooth.h>
@@ -124,12 +129,46 @@ enum qca_speed_type {
QCA_OPER_SPEED
};

+/*
+ * Voltage regulator information required for configuring the
+ * QCA Bluetooth chipset
+ */
+struct qca_vreg {
+ const char *name;
+ unsigned int min_uV;
+ unsigned int max_uV;
+ unsigned int load_uA;
+};
+
+struct qca_vreg_data {
+ enum qca_btsoc_type soc_type;
+ struct qca_vreg *vregs;
+ size_t num_vregs;
+};
+
+/*
+ * Platform data for the QCA Bluetooth power driver.
+ */
+struct qca_power {
+ struct device *dev;
+ const struct qca_vreg_data *vreg_data;
+ struct regulator_bulk_data *vreg_bulk;
+ bool vregs_on;
+};
+
struct qca_serdev {
struct hci_uart serdev_hu;
struct gpio_desc *bt_en;
struct clk *susclk;
+ enum qca_btsoc_type btsoc_type;
+ struct qca_power *bt_power;
+ u32 init_speed;
+ u32 oper_speed;
};

+static int qca_power_setup(struct hci_uart *hu, bool on);
+static void qca_power_shutdown(struct hci_uart *hu);
+
static void __serial_clock_on(struct tty_struct *tty)
{
/* TODO: Some chipset requires to enable UART clock on client
@@ -407,6 +446,7 @@ static int qca_open(struct hci_uart *hu)
{
struct qca_serdev *qcadev;
struct qca_data *qca;
+ int ret;

BT_DBG("hu %p qca_open", hu);

@@ -458,19 +498,32 @@ static int qca_open(struct hci_uart *hu)

hu->priv = qca;

- timer_setup(&qca->wake_retrans_timer, hci_ibs_wake_retrans_timeout, 0);
- qca->wake_retrans = IBS_WAKE_RETRANS_TIMEOUT_MS;
-
- timer_setup(&qca->tx_idle_timer, hci_ibs_tx_idle_timeout, 0);
- qca->tx_idle_delay = IBS_TX_IDLE_TIMEOUT_MS;
-
if (hu->serdev) {
serdev_device_open(hu->serdev);

qcadev = serdev_device_get_drvdata(hu->serdev);
- gpiod_set_value_cansleep(qcadev->bt_en, 1);
+ if (qcadev->btsoc_type != QCA_WCN3990) {
+ gpiod_set_value_cansleep(qcadev->bt_en, 1);
+ } else {
+ hu->init_speed = qcadev->init_speed;
+ hu->oper_speed = qcadev->oper_speed;
+ ret = qca_power_setup(hu, true);
+ if (ret) {
+ destroy_workqueue(qca->workqueue);
+ kfree_skb(qca->rx_skb);
+ hu->priv = NULL;
+ kfree(qca);
+ return ret;
+ }
+ }
}

+ timer_setup(&qca->wake_retrans_timer, hci_ibs_wake_retrans_timeout, 0);
+ qca->wake_retrans = IBS_WAKE_RETRANS_TIMEOUT_MS;
+
+ timer_setup(&qca->tx_idle_timer, hci_ibs_tx_idle_timeout, 0);
+ qca->tx_idle_delay = IBS_TX_IDLE_TIMEOUT_MS;
+
BT_DBG("HCI_UART_QCA open, tx_idle_delay=%u, wake_retrans=%u",
qca->tx_idle_delay, qca->wake_retrans);

@@ -554,10 +607,13 @@ static int qca_close(struct hci_uart *hu)
qca->hu = NULL;

if (hu->serdev) {
- serdev_device_close(hu->serdev);
-
qcadev = serdev_device_get_drvdata(hu->serdev);
- gpiod_set_value_cansleep(qcadev->bt_en, 0);
+ if (qcadev->btsoc_type == QCA_WCN3990)
+ qca_power_shutdown(hu);
+ else
+ gpiod_set_value_cansleep(qcadev->bt_en, 0);
+
+ serdev_device_close(hu->serdev);
}

kfree_skb(qca->rx_skb);
@@ -891,6 +947,7 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
struct hci_uart *hu = hci_get_drvdata(hdev);
struct qca_data *qca = hu->priv;
struct sk_buff *skb;
+ struct qca_serdev *qcadev;
u8 cmd[] = { 0x01, 0x48, 0xFC, 0x01, 0x00 };

if (baudrate > QCA_BAUDRATE_3200000)
@@ -904,6 +961,13 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
return -ENOMEM;
}

+ /* Disabling hardware flow control is mandate while

nit: s/mandate/mandatory|required/

+ * sending change baudrate request to wcn3990 SoC.
+ */
+ qcadev = serdev_device_get_drvdata(hu->serdev);
+ if (qcadev->btsoc_type == QCA_WCN3990)
+ hci_uart_set_flow_control(hu, true);
+
/* Assign commands to change baudrate and packet type. */
skb_put_data(skb, cmd, sizeof(cmd));
hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
@@ -919,6 +983,9 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
schedule_timeout(msecs_to_jiffies(BAUDRATE_SETTLE_TIMEOUT_MS));
set_current_state(TASK_RUNNING);

+ if (qcadev->btsoc_type == QCA_WCN3990)
+ hci_uart_set_flow_control(hu, false);
+
return 0;
}

@@ -930,6 +997,36 @@ static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
hci_uart_set_baudrate(hu, speed);
}

+static int qca_send_vendor_cmd(struct hci_dev *hdev, u8 cmd)
+{
+ struct hci_uart *hu = hci_get_drvdata(hdev);
+ struct qca_data *qca = hu->priv;
+ struct sk_buff *skb;
+
+ bt_dev_dbg(hdev, "sending command %02x to SoC", cmd);
+
+ skb = bt_skb_alloc(sizeof(cmd), GFP_KERNEL);
+ if (!skb)
+ return -ENOMEM;
+
+ /* Disabling hardware flow control is mandate while

Same nit as above

+ * sending vendor power on and off pulse to SoC.
+ */

The function is called qca_send_vendor_cmd(), the comment about power
on/off pulses seems misplaced here. Are there other 'vendor commands'
that require a different flow control behavior?

Perhaps the function should have a different name or we need another
wrapper.

+ hci_uart_set_flow_control(hu, true);

Should the changing of the flow control be limited to wcn3990? As of
now the function is only called for wcn3990, however this is not
stated as a requirement and might change in the future.

+ skb_put_u8(skb, cmd);
+ hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
+
+ skb_queue_tail(&qca->txq, skb);
+ hci_uart_tx_wakeup(hu);
+
+ /* Wait for 100 uS for SoC to settle down */
+ usleep_range(100, 200);

Is this needed for any 'vendor command' or directly related with the
power on/off pulses?

+ hci_uart_set_flow_control(hu, false);
+
+ return 0;
+}
+
static unsigned int qca_get_speed(struct hci_uart *hu,
enum qca_speed_type speed_type)
{
@@ -952,10 +1049,19 @@ static unsigned int qca_get_speed(struct hci_uart *hu,

static int qca_check_speeds(struct hci_uart *hu)
{
- /* One or the other speeds should be non zero. */
- if (!qca_get_speed(hu, QCA_INIT_SPEED) &&
- !qca_get_speed(hu, QCA_OPER_SPEED))
+ struct qca_serdev *qcadev;
+
+ qcadev = serdev_device_get_drvdata(hu->serdev);
+ if ((qcadev->btsoc_type == QCA_WCN3990 &&
+ !qca_get_speed(hu, QCA_INIT_SPEED)) ||
+ !qca_get_speed(hu, QCA_OPER_SPEED)) {
+ /* Both INIT and OPER speed should be non zero. */
return -EINVAL;
+ } else if (!qca_get_speed(hu, QCA_INIT_SPEED) &&
+ !qca_get_speed(hu, QCA_OPER_SPEED)) {
+ /* One or the other speeds should be non zero. */
+ return -EINVAL;
+ }

It is questionable if the comments are useful, they are basically
stating the same as the conditions.

if-else statements with a single statement in all branches shouldn't
use curly braces. Personally I don't dislike them in this case with
the multi-line conditions, but in principle they shoulnd't be there.

nit: this would be easier to read with nested if statements:

if (qcadev->btsoc_type == QCA_WCN3990)
if (!qca_get_speed(hu, QCA_INIT_SPEED)) ||
!qca_get_speed(hu, QCA_OPER_SPEED))
return -EINVAL;
else
if (!qca_get_speed(hu, QCA_INIT_SPEED) &&
!qca_get_speed(hu, QCA_OPER_SPEED)) {
return -EINVAL;

return 0;
}
@@ -986,15 +1092,40 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
return 0;
}

+static int qca_wcn3990_init(struct hci_uart *hu)
+{
+ int ret;
+
+ ret = qca_send_vendor_cmd(hu->hdev, QCA_WCN3990_POWERON_PULSE);
+ if (ret)
+ return ret;
+
+ /* Wait for 100 ms for SoC to boot up */
+ msleep(100);
+ serdev_device_close(hu->serdev);
+ ret = serdev_device_open(hu->serdev);
+ if (ret) {
+ bt_dev_err(hu->hdev, "failed to open port");
+ return ret;
+ }
+
+ /* Setup initial baudrate */
+ qca_set_speed(hu, QCA_INIT_SPEED);

The comment is a bit redundant.

+ hci_uart_set_flow_control(hu, false);
+
+ return 0;
+}
+
static int qca_setup(struct hci_uart *hu)
{
struct hci_dev *hdev = hu->hdev;
struct qca_data *qca = hu->priv;
unsigned int speed, qca_baudrate = QCA_BAUDRATE_115200;
+ struct qca_serdev *qcadev;
int ret;
int soc_ver = 0;

- bt_dev_info(hdev, "ROME setup");
+ qcadev = serdev_device_get_drvdata(hu->serdev);

ret = qca_check_speeds(hu);
if (ret)
@@ -1006,6 +1137,21 @@ static int qca_setup(struct hci_uart *hu)
/* Setup initial baudrate */
qca_set_speed(hu, QCA_INIT_SPEED);

+ if (qcadev->btsoc_type == QCA_WCN3990) {
+ bt_dev_dbg(hdev, "setting up wcn3990");

Seems like this should be bt_dev_info() for consistency with Rome.

+ ret = qca_wcn3990_init(hu);
+ if (ret)
+ return ret;
+
+ ret = qca_read_soc_version(hdev, &soc_ver);
+ if (ret < 0 || soc_ver == 0) {
+ bt_dev_err(hdev, "Failed to get version %d", ret);
+ return ret;
+ }
+ } else {
+ bt_dev_info(hdev, "ROME setup");
+ }
+
/* Setup user speed if needed */
speed = qca_get_speed(hu, QCA_OPER_SPEED);
if (speed) {
@@ -1016,16 +1162,18 @@ static int qca_setup(struct hci_uart *hu)
qca_baudrate = qca_get_baudrate_value(speed);
}

- /* Get QCA version information */
- ret = qca_read_soc_version(hdev, &soc_ver);
- if (ret < 0 || soc_ver == 0) {
- bt_dev_err(hdev, "QCA Failed to get version (%d)", ret);
- return ret;
+ if (!soc_ver) {


The following would probably be clearer:

if (qcadev->btsoc_type != QCA_WCN3990) {

+ /* Get QCA version information */
+ ret = qca_read_soc_version(hdev, &soc_ver);
+ if (ret < 0 || soc_ver == 0) {
+ bt_dev_err(hdev, "QCA Failed to get version (%d)", ret);
+ return ret;
+ }
+ bt_dev_info(hdev, "QCA controller version 0x%08x", soc_ver);

Couldn't we hide some of this in qca_read_soc_version()?

qca_read_soc_version() could at least do the logging in the error case
(the 'soc_ver == 0' case could be handled there as well), which would
leave us with:


ret = qca_read_soc_version(hdev, &soc_ver);
if (ret)
return ret;

And the same above.

The controller version can be logged outside of the branch for both
wcn3990 and Rome.

}
- bt_dev_info(hdev, "QCA controller version 0x%08x", soc_ver);

/* Setup patch / NVM configurations */
- ret = qca_uart_setup(hdev, qca_baudrate, QCA_ROME, soc_ver);
+ ret = qca_uart_setup(hdev, qca_baudrate, qcadev->btsoc_type, soc_ver);
if (!ret) {
set_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
qca_debugfs_init(hdev);
@@ -1061,9 +1209,123 @@ static struct hci_uart_proto qca_proto = {
.dequeue = qca_dequeue,
};

+static const struct qca_vreg_data qca_soc_data = {
+ .soc_type = QCA_WCN3990,
+ .vregs = (struct qca_vreg []) {
+ { "vddio", 1800000, 1800000, 0 },
+ { "vddxo", 1800000, 1800000, 1 },
+ { "vddrf", 1304000, 1304000, 1 },
+ { "vddch0", 3000000, 3312000, 1 },
+ },
+ .num_vregs = 4,
+};

I didn't chime in earlier in the discussion with Stephen on the
regulators (https://patchwork.kernel.org/patch/10467911/), however I
agree with him that specifying at load of 1uA doesn't seem to make
much sense. What would happen if the load remained unspecified (or 0)?

[Bala]: On RPMh based designs, calling a regulator_set_load with a non-zero value moves the regulator to NPM (high power mode) which is required for BT communication.
and call with 0uA moves it to low-power-mode (vote from APPS). Basically whenever BT wants these in NPM it calls set-load with 1.

--
Regards
Balakrishna.