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From:   Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
To:     Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Rob Herring <robh+dt@kernel.org>
Cc:     linux-bluetooth@vger.kernel.org, dianders@chromium.org,
        Abhishek Pandit-Subedi <abhishekpandit@chromium.org>,
        linux-kernel@vger.kernel.org
Subject: [PATCH v3 1/4] Bluetooth: hci_bcm: Disallow set_baudrate for BCM4354
Date:   Mon, 11 Nov 2019 16:19:46 -0800
Message-Id: <20191112001949.136377-2-abhishekpandit@chromium.org>
In-Reply-To: <20191112001949.136377-1-abhishekpandit@chromium.org>
References: <20191112001949.136377-1-abhishekpandit@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Without updating the patchram, the BCM4354 does not support a higher
operating speed. The normal bcm_setup follows the correct order
(init_speed, patchram and then oper_speed) but the serdev driver will
set the operating speed before calling the hu->setup function. Thus,
for the BCM4354, disallow setting the operating speed before patchram.
If set_baudrate is called before setup, it will return -EBUSY.

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
---

Changes in v3: None
Changes in v2: None

 drivers/bluetooth/hci_bcm.c | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
index 0f851c0dde7f..6134bff58748 100644
--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c
@@ -47,6 +47,14 @@
 
 #define BCM_NUM_SUPPLIES 2
 
+/**
+ * struct bcm_device_data - device specific data
+ * @no_early_set_baudrate: Disallow set baudrate before driver setup()
+ */
+struct bcm_device_data {
+	bool	no_early_set_baudrate;
+};
+
 /**
  * struct bcm_device - device driver resources
  * @serdev_hu: HCI UART controller struct
@@ -79,6 +87,7 @@
  * @hu: pointer to HCI UART controller struct,
  *	used to disable flow control during runtime suspend and system sleep
  * @is_suspended: whether flow control is currently disabled
+ * @disallow_set_baudrate: don't allow set_baudrate
  */
 struct bcm_device {
 	/* Must be the first member, hci_serdev.c expects this. */
@@ -112,6 +121,7 @@ struct bcm_device {
 	struct hci_uart		*hu;
 	bool			is_suspended;
 #endif
+	bool			disallow_set_baudrate;
 };
 
 /* generic bcm uart resources */
@@ -141,9 +151,13 @@ static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
 static int bcm_set_baudrate(struct hci_uart *hu, unsigned int speed)
 {
 	struct hci_dev *hdev = hu->hdev;
+	struct bcm_data *bcm = hu->priv;
 	struct sk_buff *skb;
 	struct bcm_update_uart_baud_rate param;
 
+	if (bcm && bcm->dev && bcm->dev->disallow_set_baudrate)
+		return -EBUSY;
+
 	if (speed > 3000000) {
 		struct bcm_write_uart_clock_setting clock;
 
@@ -551,6 +565,12 @@ static int bcm_setup(struct hci_uart *hu)
 		goto finalize;
 	}
 
+	/* If we disallow early set baudrate, we can re-enable it now that
+	 * patchram is done
+	 */
+	if (bcm->dev && bcm->dev->disallow_set_baudrate)
+		bcm->dev->disallow_set_baudrate = false;
+
 	/* Init speed if any */
 	if (hu->init_speed)
 		speed = hu->init_speed;
@@ -1371,6 +1391,15 @@ static struct platform_driver bcm_driver = {
 	},
 };
 
+static void bcm_configure_device_data(struct bcm_device *bdev)
+{
+	const struct bcm_device_data *data = device_get_match_data(bdev->dev);
+
+	if (data) {
+		bdev->disallow_set_baudrate = data->no_early_set_baudrate;
+	}
+}
+
 static int bcm_serdev_probe(struct serdev_device *serdev)
 {
 	struct bcm_device *bcmdev;
@@ -1408,6 +1437,8 @@ static int bcm_serdev_probe(struct serdev_device *serdev)
 	if (err)
 		dev_err(&serdev->dev, "Failed to power down\n");
 
+	bcm_configure_device_data(bcmdev);
+
 	return hci_uart_register_device(&bcmdev->serdev_hu, &bcm_proto);
 }
 
@@ -1419,12 +1450,16 @@ static void bcm_serdev_remove(struct serdev_device *serdev)
 }
 
 #ifdef CONFIG_OF
+struct bcm_device_data bcm4354_device_data = {
+	.no_early_set_baudrate = true,
+};
+
 static const struct of_device_id bcm_bluetooth_of_match[] = {
 	{ .compatible = "brcm,bcm20702a1" },
 	{ .compatible = "brcm,bcm4345c5" },
 	{ .compatible = "brcm,bcm4330-bt" },
 	{ .compatible = "brcm,bcm43438-bt" },
-	{ .compatible = "brcm,bcm43540-bt" },
+	{ .compatible = "brcm,bcm43540-bt", .data = &bcm4354_device_data },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, bcm_bluetooth_of_match);
-- 
2.24.0.rc1.363.gb1bccd3e3d-goog