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authorNico Huber <nico.h@gmx.de>2016-11-18 20:11:43 +0100
committerNico Huber <nico.h@gmx.de>2016-11-21 15:04:35 +0100
commitc868fd16a79556db6005bd784e21a654a22042c3 (patch)
tree3f2fb51700801beb07d303a63b42245d8fd657c2 /src/drivers
parent378d79eb30f1fd990a17b26840741adfce35a8a2 (diff)
downloadcoreboot-c868fd16a79556db6005bd784e21a654a22042c3.tar.xz
drivers/usb: Add option for baudrate of FT232H UART
The maximum supported rate is 12MHz. Only tested with 4MHz though, since I couldn't set anything higher on my Linux receiver. But that works fine with another FT*232H as receiver, whoosh. Change-Id: Ie39aa0170882ff5b4512f0349f6f86d3f0b86421 Signed-off-by: Nico Huber <nico.h@gmx.de> Reviewed-on: https://review.coreboot.org/17477 Tested-by: build bot (Jenkins) Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Diffstat (limited to 'src/drivers')
-rw-r--r--src/drivers/usb/Kconfig12
-rw-r--r--src/drivers/usb/gadget.c31
2 files changed, 41 insertions, 2 deletions
diff --git a/src/drivers/usb/Kconfig b/src/drivers/usb/Kconfig
index c5c1ec7187..935108fd73 100644
--- a/src/drivers/usb/Kconfig
+++ b/src/drivers/usb/Kconfig
@@ -93,10 +93,20 @@ config USBDEBUG_DONGLE_FTDI_FT232H
bool "FTDI FT232H UART"
help
Use this with FT232H usb-to-uart. Configuration is hard-coded
- to use 115200, 8n1, no flow control.
+ to use 8n1, no flow control.
endchoice
+config USBDEBUG_DONGLE_FTDI_FT232H_BAUD
+ int "FTDI FT232H baud rate"
+ default 115200
+ depends on USBDEBUG_DONGLE_FTDI_FT232H
+ help
+ Select baud rate for FT232H in the range 733..12,000,000. Make
+ sure that your receiving side supports the same setting and your
+ connection works with it. Multiples of 115,200 seem to be a good
+ choice, and EHCI debug usually can't saturate more than 576,000.
+
config USBDEBUG_OPTIONAL_HUB_PORT
int
default 2 if USBDEBUG_DONGLE_BEAGLEBONE
diff --git a/src/drivers/usb/gadget.c b/src/drivers/usb/gadget.c
index 2451cf96e8..7a1f073a5c 100644
--- a/src/drivers/usb/gadget.c
+++ b/src/drivers/usb/gadget.c
@@ -226,11 +226,38 @@ small_write:
#define FTDI_SIO_SET_DATA_REQUEST 0x04
#define FTDI_SIO_SET_BITMODE_REQUEST 0x0b
+/* Simplified divisor selection for 12MHz base clock only */
+static void ft232h_baud(u16 *const value, u16 *const index, u32 baud)
+{
+ static const u32 fraction_map[8] = { 0, 3, 2, 4, 1, 5, 6, 7 };
+
+ /* divisor must fit into 14 bits */
+ if (baud < 733)
+ baud = 733;
+
+ /* divisor is given as a fraction of 8 */
+ const u32 div8 = ((12 * 1000 * 1000) * 8) / baud;
+ /* upper 3 bits fractional part, lower 14 bits integer */
+ u32 div = fraction_map[div8 & 7] << 14 | div8 / 8;
+
+ /* special case for 12MHz */
+ if (div == 1)
+ div = 0;
+ /* special case for 8MHz */
+ else if (div == (fraction_map[4] << 14 | 1))
+ div = 1;
+
+ *value = div; /* divisor lower 16 bits */
+ *index = (div >> 8) & 0x0100; /* divisor bit 16 */
+ *index |= 0x0200; /* select 120MHz / 10 */
+}
+
static int probe_for_ftdi(struct ehci_dbg_port *ehci_debug, struct dbgp_pipe *pipe)
{
int ret;
u8 devnum = 0;
u8 uart_if = 1; /* FTDI_INTERFACE_A 1 */
+ u16 baud_value, baud_index;
/* Move the device to 127 if it isn't already there */
ret = dbgp_control_msg(ehci_debug, devnum,
@@ -260,10 +287,12 @@ static int probe_for_ftdi(struct ehci_dbg_port *ehci_debug, struct dbgp_pipe *pi
dprintk(BIOS_INFO, "FTDI SET_BITMODE failed.\n");
return -3;
}
+ ft232h_baud(&baud_value, &baud_index,
+ CONFIG_USBDEBUG_DONGLE_FTDI_FT232H_BAUD);
ret = dbgp_control_msg(ehci_debug, devnum,
USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
FTDI_SIO_SET_BAUDRATE_REQUEST,
- 0xc068, 0x0200 | uart_if, NULL, 0);
+ baud_value, baud_index | uart_if, NULL, 0);
if (ret < 0) {
dprintk(BIOS_INFO, "FTDI SET_BAUDRATE failed.\n");
return -3;