The ns8250 driver uses too many magic numbers

[Jakub Jermář]

The new ns8250 serial driver uses magic numbers when accessing I/O ports, such as in:

pio_write_8(port + 1, 0x1);     /* Interrupt when data received. */
pio_write_8(port + 4, 0xB);

It would be better to do something similar as e.g. we do in the kernel ns16550 driver. We define a structure which describes the registers of the device:

/** NS16550 registers. */
typedef struct {
        ioport8_t rbr;      /**< Receiver Buffer Register. */
        ioport8_t ier;      /**< Interrupt Enable Register. */
        union {
                ioport8_t iir;  /**< Interrupt Ident Register (read). */
                ioport8_t fcr;  /**< FIFO control register (write). */
        } __attribute__ ((packed));
        ioport8_t lcr;      /**< Line Control register. */
        ioport8_t mcr;      /**< Modem Control Register. */
        ioport8_t lsr;      /**< Line Status Register. */
} __attribute__ ((packed)) ns16550_t;

and then comfortably access it like this:

if (pio_read_8(&dev->lsr) & LSR_DATA_READY) {
        uint8_t data = pio_read_8(&dev->rbr);
        ...
}

Of course, the constants should be replaced with symbolic constants as well.

[Jakub Jermář]

Fixed in mainline,1452.