Received-SPF: pass (google.com: domain of linux-bluetooth-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Hakan Jansson <hakan.jansson@infineon.com>
CC:     Hakan Jansson <hakan.jansson@infineon.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        <netdev@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        "Luiz Augusto von Dentz" <luiz.dentz@gmail.com>,
        <linux-bluetooth@vger.kernel.org>
Subject: [PATCH 2/2] Bluetooth: hci_bcm: Add support for FW loading in autobaud mode
Date:   Wed, 4 May 2022 11:03:40 +0200
Message-ID: <ef9c70687b300ff96f056339a5680d3470090235.1651647576.git.hakan.jansson@infineon.com>
In-Reply-To: <cover.1651647576.git.hakan.jansson@infineon.com>
References: <cover.1651647576.git.hakan.jansson@infineon.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
To:     unlisted-recipients:; (no To-header on input)
Precedence: bulk

Some devices (e.g. CYW5557x) require autobaud mode to enable FW loading.
Autobaud mode can also be required on some boards where the controller
device is using a non-standard baud rate when first powered on.

Only a limited subset of HCI commands are supported in autobaud mode.

This patch looks for a DT property, "brcm,uses-autobaud-mode", to enable
autobaud mode selection. If the property is present, the device is started
in autobaud mode by keeping RTS asserted while powering on the device. The
patch also prevents the use of unsupported commands for devices started in
autobaud mode.

Signed-off-by: Hakan Jansson <hakan.jansson@infineon.com>
---
 drivers/bluetooth/btbcm.c   | 31 +++++++++++++++++++++++--------
 drivers/bluetooth/btbcm.h   |  8 ++++----
 drivers/bluetooth/hci_bcm.c | 15 ++++++++++++---
 3 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/drivers/bluetooth/btbcm.c b/drivers/bluetooth/btbcm.c
index 92a2b7e81757..0c0958030c0a 100644
--- a/drivers/bluetooth/btbcm.c
+++ b/drivers/bluetooth/btbcm.c
@@ -403,6 +403,13 @@ static int btbcm_read_info(struct hci_dev *hdev)
 	bt_dev_info(hdev, "BCM: chip id %u", skb->data[1]);
 	kfree_skb(skb);
 
+	return 0;
+}
+
+static int btbcm_print_controller_features(struct hci_dev *hdev)
+{
+	struct sk_buff *skb;
+
 	/* Read Controller Features */
 	skb = btbcm_read_controller_features(hdev);
 	if (IS_ERR(skb))
@@ -513,7 +520,7 @@ static const char *btbcm_get_board_name(struct device *dev)
 #endif
 }
 
-int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done)
+int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode)
 {
 	u16 subver, rev, pid, vid;
 	struct sk_buff *skb;
@@ -550,9 +557,16 @@ int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done)
 		if (err)
 			return err;
 	}
-	err = btbcm_print_local_name(hdev);
-	if (err)
-		return err;
+
+	if (!use_autobaud_mode) {
+		err = btbcm_print_controller_features(hdev);
+		if (err)
+			return err;
+
+		err = btbcm_print_local_name(hdev);
+		if (err)
+			return err;
+	}
 
 	bcm_subver_table = (hdev->bus == HCI_USB) ? bcm_usb_subver_table :
 						    bcm_uart_subver_table;
@@ -635,13 +649,13 @@ int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done)
 }
 EXPORT_SYMBOL_GPL(btbcm_initialize);
 
-int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done)
+int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode)
 {
 	int err;
 
 	/* Re-initialize if necessary */
 	if (*fw_load_done) {
-		err = btbcm_initialize(hdev, fw_load_done);
+		err = btbcm_initialize(hdev, fw_load_done, use_autobaud_mode);
 		if (err)
 			return err;
 	}
@@ -657,15 +671,16 @@ EXPORT_SYMBOL_GPL(btbcm_finalize);
 int btbcm_setup_patchram(struct hci_dev *hdev)
 {
 	bool fw_load_done = false;
+	bool use_autobaud_mode = false;
 	int err;
 
 	/* Initialize */
-	err = btbcm_initialize(hdev, &fw_load_done);
+	err = btbcm_initialize(hdev, &fw_load_done, use_autobaud_mode);
 	if (err)
 		return err;
 
 	/* Re-initialize after loading Patch */
-	return btbcm_finalize(hdev, &fw_load_done);
+	return btbcm_finalize(hdev, &fw_load_done, use_autobaud_mode);
 }
 EXPORT_SYMBOL_GPL(btbcm_setup_patchram);
 
diff --git a/drivers/bluetooth/btbcm.h b/drivers/bluetooth/btbcm.h
index 8bf01565fdfc..b4cb24231a20 100644
--- a/drivers/bluetooth/btbcm.h
+++ b/drivers/bluetooth/btbcm.h
@@ -62,8 +62,8 @@ int btbcm_write_pcm_int_params(struct hci_dev *hdev,
 int btbcm_setup_patchram(struct hci_dev *hdev);
 int btbcm_setup_apple(struct hci_dev *hdev);
 
-int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done);
-int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done);
+int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode);
+int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode);
 
 #else
 
@@ -104,12 +104,12 @@ static inline int btbcm_setup_apple(struct hci_dev *hdev)
 	return 0;
 }
 
-static inline int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done)
+static inline int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode)
 {
 	return 0;
 }
 
-static inline int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done)
+static inline int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode)
 {
 	return 0;
 }
diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
index 785f445dd60d..0230cfcc8e3e 100644
--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c
@@ -99,6 +99,7 @@ struct bcm_device_data {
  * @no_early_set_baudrate: don't set_baudrate before setup()
  * @drive_rts_on_open: drive RTS signal on ->open() when platform requires it
  * @pcm_int_params: keep the initial PCM configuration
+ * @use_autobaud_mode: start Bluetooth device in autobaud mode
  */
 struct bcm_device {
 	/* Must be the first member, hci_serdev.c expects this. */
@@ -136,6 +137,7 @@ struct bcm_device {
 #endif
 	bool			no_early_set_baudrate;
 	bool			drive_rts_on_open;
+	bool			use_autobaud_mode;
 	u8			pcm_int_params[5];
 };
 
@@ -472,7 +474,9 @@ static int bcm_open(struct hci_uart *hu)
 
 out:
 	if (bcm->dev) {
-		if (bcm->dev->drive_rts_on_open)
+		if (bcm->dev->use_autobaud_mode)
+			hci_uart_set_flow_control(hu, false);	/* Assert BT_UART_CTS_N */
+		else if (bcm->dev->drive_rts_on_open)
 			hci_uart_set_flow_control(hu, true);
 
 		hu->init_speed = bcm->dev->init_speed;
@@ -564,6 +568,7 @@ static int bcm_setup(struct hci_uart *hu)
 {
 	struct bcm_data *bcm = hu->priv;
 	bool fw_load_done = false;
+	bool use_autobaud_mode = (bcm->dev ? bcm->dev->use_autobaud_mode : 0);
 	unsigned int speed;
 	int err;
 
@@ -572,7 +577,7 @@ static int bcm_setup(struct hci_uart *hu)
 	hu->hdev->set_diag = bcm_set_diag;
 	hu->hdev->set_bdaddr = btbcm_set_bdaddr;
 
-	err = btbcm_initialize(hu->hdev, &fw_load_done);
+	err = btbcm_initialize(hu->hdev, &fw_load_done, use_autobaud_mode);
 	if (err)
 		return err;
 
@@ -616,7 +621,7 @@ static int bcm_setup(struct hci_uart *hu)
 		btbcm_write_pcm_int_params(hu->hdev, &params);
 	}
 
-	err = btbcm_finalize(hu->hdev, &fw_load_done);
+	err = btbcm_finalize(hu->hdev, &fw_load_done, use_autobaud_mode);
 	if (err)
 		return err;
 
@@ -1197,6 +1202,10 @@ static int bcm_acpi_probe(struct bcm_device *dev)
 
 static int bcm_of_probe(struct bcm_device *bdev)
 {
+	bdev->use_autobaud_mode = device_property_read_bool(bdev->dev, "brcm,uses-autobaud-mode");
+	if (bdev->use_autobaud_mode)
+		bdev->no_early_set_baudrate = true;
+
 	device_property_read_u32(bdev->dev, "max-speed", &bdev->oper_speed);
 	device_property_read_u8_array(bdev->dev, "brcm,bt-pcm-int-params",
 				      bdev->pcm_int_params, 5);
-- 
2.25.1