diff options
| author | Nico Huber <nico.h@gmx.de> | 2016-11-18 20:11:43 +0100 |
|---|---|---|
| committer | Nico Huber <nico.h@gmx.de> | 2016-11-21 15:04:35 +0100 |
| commit | c868fd16a79556db6005bd784e21a654a22042c3 (patch) | |
| tree | 3f2fb51700801beb07d303a63b42245d8fd657c2 /src/drivers/usb/gadget.c | |
| parent | 378d79eb30f1fd990a17b26840741adfce35a8a2 (diff) | |
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/usb/gadget.c')
| -rw-r--r-- | src/drivers/usb/gadget.c | 31 |
1 files changed, 30 insertions, 1 deletions
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; |