[PATCH] Bluetooth: hci_ll: Add optional nvmem BD address source

David Lechner
2017-12-12T22:00:05Z

This adds an optional nvmem consumer to get a BD address from an external
source. The BD address is then set in the Bluetooth chip after the
firmware has been loaded.

This has been tested working with a TI CC2560A chip (in a LEGO MINDSTORMS
EV3).

Signed-off-by: David Lechner <david@lechnology.com>
---
drivers/bluetooth/hci_ll.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)

diff --git a/drivers/bluetooth/hci_ll.c b/drivers/bluetooth/hci_ll.c
index c948e8d..ed042ae 100644
--- a/drivers/bluetooth/hci_ll.c
+++ b/drivers/bluetooth/hci_ll.c
@@ -53,6 +53,7 @@
#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <linux/gpio/consumer.h>
+#include <linux/nvmem-consumer.h>

#include "hci_uart.h"

@@ -90,6 +91,7 @@ struct ll_device {
struct serdev_device *serdev;
struct gpio_desc *enable_gpio;
struct clk *ext_clk;
+ bdaddr_t bdaddr;
};

struct ll_struct {
@@ -719,6 +721,18 @@ static int ll_setup(struct hci_uart *hu)
if (err)
return err;

+ /* Set BD address if one was specified at probe */
+ if (!bacmp(&lldev->bdaddr, BDADDR_NONE)) {
+ /* This means that there was an error getting the BD address
+ * during probe, so mark the device as having a bad address.
+ */
+ set_bit(HCI_QUIRK_INVALID_BDADDR, &hu->hdev->quirks);
+ } else if (bacmp(&lldev->bdaddr, BDADDR_ANY)) {
+ err = ll_set_bdaddr(hu->hdev, &lldev->bdaddr);
+ if (err)
+ set_bit(HCI_QUIRK_INVALID_BDADDR, &hu->hdev->quirks);
+ }
+
/* Operational speed if any */
if (hu->oper_speed)
speed = hu->oper_speed;
@@ -749,6 +763,7 @@ static int hci_ti_probe(struct serdev_device *serdev)
{
struct hci_uart *hu;
struct ll_device *lldev;
+ struct nvmem_cell *bdaddr_cell;
u32 max_speed = 3000000;

lldev = devm_kzalloc(&serdev->dev, sizeof(struct ll_device), GFP_KERNEL);
@@ -770,6 +785,52 @@ static int hci_ti_probe(struct serdev_device *serdev)
of_property_read_u32(serdev->dev.of_node, "max-speed", &max_speed);
hci_uart_set_speeds(hu, 115200, max_speed);

+ /* optional BD address from nvram */
+ bdaddr_cell = nvmem_cell_get(&serdev->dev, "bd-address");
+ if (IS_ERR(bdaddr_cell)) {
+ int err = PTR_ERR(bdaddr_cell);
+
+ if (err == -EPROBE_DEFER)
+ return err;
+
+ /* ENOENT means there is no matching nvmem cell and ENOSYS
+ * means that nvmem is not enabled in the kernel configuration.
+ */
+ if (err != -ENOENT && err != -ENOSYS) {
+ /* If there was some other error, give userspace a
+ * chance to fix the problem instead of failing to load
+ * the driver. Using BDADDR_NONE as a flag that is
+ * tested later in the setup function.
+ */
+ dev_warn(&serdev->dev,
+ "Failed to get \"bd-address\" nvmem cell (%d)\n",
+ err);
+ bacpy(&lldev->bdaddr, BDADDR_NONE);
+ }
+ } else {
+ bdaddr_t *bdaddr;
+ int len;
+
+ bdaddr = nvmem_cell_read(bdaddr_cell, &len);
+ nvmem_cell_put(bdaddr_cell);
+ if (IS_ERR(bdaddr)) {
+ dev_err(&serdev->dev, "Failed to read nvmem bd-address\n");
+ return PTR_ERR(bdaddr);
+ }
+ if (len != sizeof(bdaddr_t)) {
+ dev_err(&serdev->dev, "Invalid nvmem bd-address length\n");
+ kfree(bdaddr);
+ return -EINVAL;
+ }
+
+ /* As per the device tree bindings, the value from nvmem is
+ * expected to be MSB first, but in the kernel it is expected
+ * that bdaddr_t is LSB first.
+ */
+ baswap(&lldev->bdaddr, bdaddr);
+ kfree(bdaddr);
+ }
+
return hci_uart_register_device(hu, &llp);
}

--
2.7.4