Serocco PEB/PEF 20532 Linux 2.6.12 driver.

The driver supports both ports on the serocco and each one can be configured in async or HDLC mode. Async mode was tested both with a PC and an ISDN modem. The throughput is as expected. Hardware flow control is supported too but standard Linux way of doing it is used (no specific HW support for flow-control is used). HDLC mode was tested between 2 serocco based boards (for now, further testing with third party devices is planned ASAP). The standard Linux sethdlc utility may be used for tuning the communications parameters.

The platform data needed is rather simple, I had no control over the main kernel:

static struct resource serocco_resource = {
        .start  = SEROCCO_PHYS,
        .end    = (SEROCCO_PHYS + SEROCCO_SIZE),
        .flags  = IORESOURCE_MEM,
};


static struct platform_device serocco_device = {
        .name           = "serocco",
        .id             = 0,
        .num_resources  = 1,
        .resource       = &serocco_resource,
};

• The defines which start with DEBUG activate various debugging information. If you find problems with this driver please recompile the module with at least some of these activated and send me the debugging trace.
• SEROCCO_BUS_MULT defines the factor by which multiply the register address when accessing them.
• SEROCCO_RESET_PIN and SEROCCO_IRQ_PIN define the gpio number for the reset and the irq pin of the serocco.
• UART_CLOCK is the frequency (in Hz) of the crystal connected to the serocco.
• The module parameters serocco_port_a_mode and serocco_port_b_mode define the mode for the 2 ports present on the chip. 0 is off, 1 is async and 2 is sync.
• The structs serocco_pins_port_a and serocco_pins_port_b define the pins used when implementing the RS232 standard interface.

• Sandro Mascetti and Nicola Perrino from At Lab (http://www.atlab.it/) that helped me in debugging the driver. And, of course, At Lab itself that commissioned the driver.
• Rodolfo Giometti that wrote a driver for the HDLC part of the serocco for the Linux 2.4 kernel. You can find it at his site http://www.enneenne.com.