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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>
This commit is contained in:
Nico Huber 2016-11-18 20:11:43 +01:00
parent 378d79eb30
commit c868fd16a7
2 changed files with 41 additions and 2 deletions
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12
src/drivers/usb/Kconfig
View File

@ -93,10 +93,20 @@ config USBDEBUG_DONGLE_FTDI_FT232H
bool "FTDI FT232H UART" bool "FTDI FT232H UART"
help help
Use this with FT232H usb-to-uart. Configuration is hard-coded 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 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 config USBDEBUG_OPTIONAL_HUB_PORT
int int
default 2 if USBDEBUG_DONGLE_BEAGLEBONE default 2 if USBDEBUG_DONGLE_BEAGLEBONE

31
src/drivers/usb/gadget.c
View File

@ -226,11 +226,38 @@ small_write:
#define FTDI_SIO_SET_DATA_REQUEST 0x04 #define FTDI_SIO_SET_DATA_REQUEST 0x04
#define FTDI_SIO_SET_BITMODE_REQUEST 0x0b #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) static int probe_for_ftdi(struct ehci_dbg_port *ehci_debug, struct dbgp_pipe *pipe)
{ {
int ret; int ret;
u8 devnum = 0; u8 devnum = 0;
u8 uart_if = 1; /* FTDI_INTERFACE_A 1 */ u8 uart_if = 1; /* FTDI_INTERFACE_A 1 */
u16 baud_value, baud_index;
/* Move the device to 127 if it isn't already there */ /* Move the device to 127 if it isn't already there */
ret = dbgp_control_msg(ehci_debug, devnum, 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"); dprintk(BIOS_INFO, "FTDI SET_BITMODE failed.\n");
return -3; return -3;
} }
ft232h_baud(&baud_value, &baud_index,
CONFIG_USBDEBUG_DONGLE_FTDI_FT232H_BAUD);
ret = dbgp_control_msg(ehci_debug, devnum, ret = dbgp_control_msg(ehci_debug, devnum,
USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
FTDI_SIO_SET_BAUDRATE_REQUEST, FTDI_SIO_SET_BAUDRATE_REQUEST,
0xc068, 0x0200 | uart_if, NULL, 0); baud_value, baud_index | uart_if, NULL, 0);
if (ret < 0) { if (ret < 0) {
dprintk(BIOS_INFO, "FTDI SET_BAUDRATE failed.\n"); dprintk(BIOS_INFO, "FTDI SET_BAUDRATE failed.\n");
return -3; return -3;